Acta Radiologica

To investigate whether Dy-DTPA-BMA-enhanced MR imaging would permit identification of myocardial cell death, myocardial infarction was induced in 12 domestic pigs.

In 6 pigs with irreversible cell damage, Dy-DTPA-BMA (1.0 mmol/kg b.w.) was administered i.v. 70 min after coronary occlusion. In 6 other pigs, the infarctions were reperfused 80 min after the occlusion, followed by injection of Dy-DTPA-BMA after 30 min of reperfusion. In 4 additional pigs, the hearts were reperfused after 2 min of occlusion. All 16 pigs were sacrificed 10 min after the injection of Dy-DTPA-BMA. The hearts were excised and imaged with MR.

Reversibly injured myocardium could not be distinguished from adjacent nonischaemic myocardium after the administration of Dy-DTPA-BMA. Reperfused, infarcted myocardium demonstrated a high signal intensity in the proton-density- and T2-weighted sequences, despite a 5-fold higher Dy concentration compared with both nonreperfused infarcted and nonischaemic myocardium.

This lack of susceptibility effect in infarcted myocardium, due to a homogeneous distribution of Dy, indicates the usefulness of Dy as a marker of tissue viability.

Myocardial infarctions were induced in 12 pigs to investigate whether a double-contrast method, combining a positive and a negative MR contrast agent, could improve the visualization of reperfused myocardial infarctions.

All 12 pigs were subjected to 80 min of occlusion followed by reperfusion. In the double-contrast group (6 pigs), Gd-DTPA-BMA (0.3 mmol/kg b.w.) and Dy-DTPA-BMA (1.0 mmol/kg b.w.) were administered i.v. after 30 min of reperfusion. In the remaining 6 pigs, a single injection of Gd-DTPA-BMA (0.3 mmol/kg b.w.) was given after 30 min of reperfusion. All pigs were sacrificed 10 min postcontrast injection, corresponding to a reperfusion time of 40 min. The hearts were excised and imaged with MR. The concentrations of Gd and Dy were measured in infarcted and nonischaemic myocardium using ICP-AES.

Contrast media concentrations were more than 4-fold higher in infarcted compared with nonischaemic myocardium. The infarctions were best shown on T1-weighted images, and there were no differences between the double and single contrast groups. In the T2-weighted images, the infarctions were significantly better visualized in the double-contrast group, due to a Dy-induced signal intensity loss in nonischaemic myocardium.

The long-term effect of percutaneous transluminal renal angioplasty (PTRA) was assessed in 50 patients with renovascular hypertension.

Thirty-eight of the patients had atherosclerotic disease and 12 patients fibromuscular dysplasia (FMD). Dilatation with a balloon catheter was performed at 6 to 8 atm for 15 to 30 s.

PTRA was technically successful in 46 (92%) patients. Three of the failures underwent surgical revascularization. There was no mortality connected with PTRA. Minor complications occurred in 6 (12%) patients, and surgical intervention was required in 1. In 4 patients with restenosis, repeated PTRA was performed in 2, and surgery in the other 2 patients. Bilateral disease occurred in 12 patients, and 3 had sequential bilateral PTRA. In 9 patients with atherosclerotic ostial stenosis, PTRA was technically successful in 8 (89%). Thirty-eight patients were re-examined with a mean follow-up of 4 years. At follow-up, 5 (45%) of the patients with FMD were classified as cured, 6 (55%) as improved, and none as failed. In the 27 patients with atherosclerotic disease, 23 (85%) had long-term benefit, 3 (11%) were cured, 20 (74%) were improved, and 4 (15%) were failures. In the 8 patients with ostial atherosclerotic lesions and successful PTRA, there was a 75% long-term benefit. Two patients died during follow-up, both from myocardial infarction.

The results suggest that PTRA is effective in long-term management of renovascular hypertension, not only in patients with fibromuscular stenosis, but also in patients with atherosclerotic disease, even when ostial lesions are present.

The aim of the study was to evaluate percutaneous pancreatography as an alternative method for pancreatic duct visualisation in patients with pancreatic disease.

In 21 patients with pancreatic disease and previously unsuccessful ERCP, puncture of the pancreatic duct was carried out under ultrasonographic guidance with an 0.7-mm Chiba needle, and contrast injection was made under fluoroscopic control in the pancreatic duct.

The procedure was successful in 18 patients (86%). In 10 patients, chronic pancreatitis was found, and in 8 patients, pancreatic carcinoma.

Percutaneous pancreatography is a good alternative method for visualisation of the pancreatic duct in patients with pancreatic disease and previously unsuccessful ERCP.

The aim of the study was to improve the chondromalacia patellae (CMP) diagnosis by MR imaging under defined compression of the retropatellar cartilage, using a specially designed knee compressor. The results were compared with histological findings to obtain an MR classification of CMP.

MR imaging was performed in in vitro studies of 25 knees from cadavers to investigate the effects of compression on the retropatellar articular cartilage. The results were verified by subsequent histological evaluation.

There was a significant difference in cartilage thickness reduction and signal intensity behaviour under compression according to the stage of CMP.

Based on the decrease in cartilage thickness, signal intensity behaviour under compression, and cartilage morphology, the studies permitted an MR classification of CMP into stages I—IV in line with the histological findings. Healthy cartilage was clearly distinguished, a finding which may optimize CMP diagnosis.

The aims of this study were to examine the bone areal density of the head and how it varied in relation to the density of the rest of the skeleton, and with age, and body mass index (BMI). Our intention was to study the feasibility of excluding the head from the rest of the body, a method which might improve the fracture prediction power of bone mineral measurements.

Bone mineral per area (BMA) and bone mineral content (BMC) (g) were determined in 100 consecutive female volunteers, aged 17 to 78 years, with total and partial body measurements.

BMC of the head was found to be 20.2±2.2% of that for the total body. The BMA of the head was 2.38±0.21 times higher than that of the rest of the body. The correlation between the BMA of the head and the rest of the body was significant (r=0.73). The average change in z-score (referred to the same age group in our material) was 0.20 when the head was excluded from total body BMA. The BMA of a) total body, b) total body, head excluded, and c) head decreased with age. The BMA of the head was correlated to BMI in the older age groups (p<0.01). The relative statistical uncertainty for repeated measurement of head BMA was 1.8%.

The change of the bone density of the head with age and BMI, in comparison to that of the rest of the skeleton, suggests that when the head is excluded from total body BMA better predictive value for fracture risk is obtained.

The clinical usefulness of an advanced image-processing system called “dynamic range control processing” was investigated, with which selected parts of the dynamic range of digital chest images could be controlled.

A comparative study of 3 different post-processed formats of storage phosphor (SR) images was performed in 35 patients with abnormalities in the chest. The 3 formats were SR images with standard mode (SR-standard), SR images with strong edge-enhancement (SR-enhanced), and dynamic range controlled SR images (SR-controlled).

For lung abnormalities, there was no difference among the 3 SR image formats. For normal mediastinal structures and lung abnormalities covered by the heart or diaphragm, SR-controlled and SR-enhanced images were significantly superior to SR-standard images, while no difference was found between SR-controlled and SR-enhanced images except for the trachea and bony structures.

Dynamic range control processing appears to be a useful method for displaying SR chest images with an extremely wide dynamic range.

The occurrence of side-effects such as visceral malaise after intrathecal administration of the non-ionic radiography contrast media iomeprol, iopamidol, and iotrolan was assessed in rats by the conditioned taste aversion procedure.

Reduced preference towards a saccharose solution compared with normal water following intraventricular administration of a contrast medium was used as a measure of the aversive response.

At a dose of 100 mg I/kg none of the tested contrast media induced aversion. At 200 and 300 mg I/kg, both iopamidol and iomeprol induced significant aversive responses with respect to control, although the response of the iomeprol group appeared milder than that of the iopamidol group at a dose of 200 mg I/kg. Iotrolan could be tested only at the lowest dose since the high doses caused excessive mortality.

Intrathecally administered iomeprol appeared to be well tolerated in rats at doses higher than those suggested for clinical use.

To evaluate the effect of radiation dose reduction on image quality in computed musculoskeletal radiography and determine optimal exposure range.

In 11 corpses, 1 hand and 1 hip were examined with film-screen radiography, and a series of computed radiographs was obtained using exactly the same technique except for the exposure, which was 100, 50, 25, 12.5, 6.25, and 1.56% of the mAs numbers used for the film-screen images. The computed hip radiographs were processed in 2 different ways, one simulating the film-screen images and one using contrast enhancement. Four radiologists reviewed the images regarding the following parameters: cortical bone, trabecular bone, joint space, and soft tissue, giving each a diagnostic quality rating on a scale from 1 to 5. The median and mean values were found for the pooled results.

For the hands, the computed radiographs were ranked inferior to the film-screen images for all parameters except soft tissue, where the computed radiographs scored higher. The computed images with 50 and 25% exposure were ranked equal to the 100% ones. The quality rating slowly declined with lower exposures. For the hips, the 100 and 50% computed radiographs were generally similar to or slightly better than the film-screen images. The decline was somewhat faster than for the hands. The contrast-enhanced hip images scored less than the nonenhanced images at any given exposure for all parameters except soft tissue, where the contrast-enhanced images scored better at all exposures. The difference between nonenhanced and enhanced images became less at the lower exposures.

Lowering the exposure in computed musculoskeletal radiography below the level of film-screen radiography is feasible, especially in the peripheral skeleton. Contrast enhancement seems to be valuable only in the evaluation of soft-tissue structures.

The aim of the study was to investigate the performance of different types of equipment for bone mineral assessment in Sweden and Norway with standardised phantoms.

Measurements of the bone mineral content of 2 semi-anthropomorphic phantoms, one simulating the human torso and one the lower arm, at 21 hospitals in Norway and Sweden, were undertaken. The phantoms had inserts of hydroxyapatite in different concentrations and were measured together with additions of stearic acid simulating fat. The phantoms were repeatedly measured on 14 dual X-ray absorptiometry, 5 single X-ray absorptiometry, and 3 single photon absorptiometry devices and 1 quantitative CT device.

The measurements showed a large spread in the measured hydroxyapatite concentrations among different devices. The inaccuracy was slightly lower than 10% without fat present when the results were expressed as bone mineral areal mass (BMA, g/cm²). With fat included the inaccuracy was at worst 50%.

The large inaccuracy found in this study gives rise to a large overlap between healthy and osteoporotic cases and makes the diagnosis of osteoporosis difficult in the individual patient.

Our purpose was to evaluate how MR imaging depicts the vascular fibrofatty structure of hemangiomas.

MR images of 16 histologically proven skeletal muscle hemangiomas were reviewed retrospectively in a nonblinded manner. One patient was examined at 0.5 T, 9 at 1.0 T, and 6 at 1.5 T, and the imaging protocols varied.

All lesions were lobulated/tubular. Signal characteristics of fat were seen in 13 lesions as lace-like thin septa within or around the tumor. All 16 studies exhibited a hyperintense signal on T2-weighted spin-echo (SE) (n=15) or T1-weighted fast fat suppressed inversion recovery SE images (n=1). Postcontrast images showed marked signal enhancement in parts of the areas, both of high and low T2-weighted signal. Surgical staging based on MR images was correct in all lesions.

MR images display the characteristic vascular fibrofatty structure of hemangiomas and may allow correct diagnosis.

Presentation of a case of simultaneous lumbar disk herniation and epidural hematoma.

An 85-year-old patient with symptoms of compression of one or more nerve roots was examined with CT of the 3 lower lumbar intervertebral spaces.

CT showed a high-density mass in the left side of the spinal canal, lying on the flaval ligament and extending laterally under the left pedicle of the 3rd lumbar vertebra. The correct diagnosis was not established before surgery. At surgery, a lumbar disk herniation and an epidural hematoma, located in the 3rd lumbar intervertebral space, were found.

Retrospectively, the CT appearance was well in accordance with the findings at operation, but further examination, preferably MR imaging, is suggested in cases of atypical masses in the spinal canal.

The aim of the investigation was to determine whether thin-section high-resolution CT imaging could replace MR imaging and/or myelography in preoperative evaluation of radiculopathy and/or myelopathy.

A total of 120 patients, referred for cervical myelography (n=107) or MR imaging (n=13), were further examined with 1-mm non-contrast CT of the suspected disc space, including at least the next cephalic and caudal interspaces. Thirty-seven patients underwent Cloward's operation, at which 32 were found to have disc herniation.

The sensitivities of CT (n=37), myelography (n=29), and MR imaging (n=8) were 66%, 84%, and 86%, respectively. The corresponding figures for false-positives were 8%, 10%, and 13%. Artefacts caused by wide shoulders in the 1-mm CT images were estimated to have contributed to a false-negative finding in 8 cases. The remaining 3 false-negatives were retrospectively considered evaluation errors. The true-positive CT findings usually presented with a local disc bulge measuring over 80 HU in density. Local ligamentous hypertrophy presented an indistinguishable finding in 3 cases, yielding false-positive CT findings.

Conventional thin-section CT is considered a usable alternative for the evaluation of suspected cervical disc herniations in selected patients. Stocky patients with wide shoulders and a short neck are not suitable candidates, even when new generation equipment is available.

The aim of the investigation was to evaluate poor outcome following spinal cervical surgery.

A total of 146 consecutive patients operated with anterior discectomy and fusion (ADF) with the Cloward technique were investigated. Clinical notes, plain radiography, CT, and fast spin-echo (FSE) images were retrospectively evaluated.

Some 30% of the patients had unsatisfactory clinical results within 12 months after surgery; 13% had initial improvement followed by deterioration of the preoperative symptoms, while 14.4% were not improved or worsened. Disc herniation and bony stenosis above, below, or at the fused level were the most common findings. In 45% of patients, surgery failed to decompress the spinal canal. In only 4 patients was no cause of remaining myelopathy and/or radiculopathy found. FSE demonstrated a large variety of pathological findings in the patients with poor clinical outcome after ADF. Postoperatively, patients with good clinical outcome had a lower incidence of pathological changes.

FSE is considered the primary imaging modality for the cervical spine. However, CT is a useful complement in the axial projection to visualize bone changes.

The aim of this study was to determine the accuracy of length measurements on plain radiographs during leg lengthening and to evaluate a reliable method of measuring the amount of lengthening suitable for clinical praxis.

In an experimental study, a plastic femur was lengthened 40 mm and assessed radiographically in different positions, and the orthoradiographically calculated total length of the femur was compared with the true value. In a clinical study, 96 radiographs encompassing 14 femoral and 2 tibial lengthenings were assessed on a digitized table with a computer program (PROFILE) with regard to the amount of lengthening and the degree of magnification.

The radiographic magnification in the experimental study, depending on position of the femur, was 17% (5–25%), and in the clinical material it averaged 16% (0–36%).

Radiographs obtained with a radiopaque ruler placed at the same level as the lengthened bone allowed reliable measurements of the distraction gap.

To describe CT and MR features of extension to the petrous bone, which is a rare complication of acquired cholesteatoma (AC).

Postcontrast CT was performed in 4 patients, in axial (n=4) and coronal planes (n=2). The section thickness was 1.2 or 2.5 mm. MR was performed in 3 cases, using T1- and T2-weighted images (n=3) and postcontrast T1-weighted images (n=2).

CT demonstrated a well-outlined lesion involving the petrous bone (n=4). Density could be assessed in 3 cases, showing a hypodense unenhanced mass. Lateral (n=1), superior (n=2), and posterior (n=2) semicircular canals were affected in 3 patients. AC extended to the vestibula, cochlea, and internal acoustic meatus (IAM) in 3 patients. Two ACs extended to the level of IAM, whereas 2 extended further, to the petrous apex. In one case the sphenoid sinus was affected. On MR imaging the lesion was hypointense relative to brain on T1-weighted images and hyperintense on T2-weighted images. MR imaging helped to delineate the lesion and to distinguish it from other cystic lesions of the petrous bone.

CT and MR offer accurate preoperative assessment of the extension of cholesteatoma, which helps to choose the surgical approach.

To measure blood flow and velocity in the superior sagittal sinus.

MR velocity mapping was used to examine 14 healthy volunteers, 15 patients with normal pressure hydrocephalus (NPH), 3 patients with high pressure hydrocephalus (HPH), and 11 patients with idiopathic intracranial hypertension (IIH).

Mean blood flow was 443 ml/min in healthy volunteers with a tendency towards reduced blood flow with increasing age. In NPH patients significantly lower superior sagittal sinus blood flow values were found, but this difference was no longer significant when patients and controls were matched for age. In HPH and IIH patients blood flow and velocity were within the normal range. In one patient with thrombosis of the superior sagittal sinus the blood flow was reduced to 40 ml/min.

MR velocity mapping methods may be of value in the assessment of blood flow in the dural sinuses in various pathologies resulting in dural sinus occlusion, such as dural sinus thrombosis, and for following the progress of these patients while undergoing treatment.

To use MR to examine patients with CNS symptoms indicating chronic intoxication.

Thirty-two subjects exposed to industrial solvents for 5 to 28 years and 40 age-matched, healthy controls were examined.

All patients showed decreased signal in the basal ganglia on T2-weighted images. In 11 of the patients the white matter showed diffuse hyperintensity with loss of the grey-white matter discrimination and with distinct periventricular hyperintensities in 5 of the patients. The controls had no pathological changes in the brain.

Although the relatively small number of patients may obscure the significance, findings observed on T2-weighted images were patchy periventricular hyperintensities and hypointensities in the basal ganglia. Fast spin-echo is a good technique with fast acquisition of images with true spin-echo contrast features.

Evaluation of positron emission tomography (PET) using ¹⁸F-2-fluoro-2-deoxy-d-glucose (¹⁸FDG) and l-methyl-¹¹C-methionine in the diagnosis and staging of urinary bladder carcinoma.

Twenty-three patients with biopsy-proven urinary bladder carcinoma were examined with PET after intravenous injection of ¹¹C-methionine; 2 were also examined with ¹⁸FDG. The results from the PET investigations were compared with CT or MR findings and TNM classification before and after treatment.

The urinary excretion of ¹⁸FDG prevented distinction of the primary tumour from the surrounding tracer. With ¹¹C-methionine it was possible to detect 18/23 primary tumours. A trend was seen, suggesting that the higher the uptake values of ¹¹C-methionine in the tumour, the greater the tumour stage.

It is possible to visualize urinary bladder tumours larger than 1 cm in diameter with PET using ¹¹C-methionine, but the value of the method in the staging of the lesions is not superior to conventional methods.

We evaluated the usefulness of dynamic 3-dimensional Fourier transformation (3DFT) fast low angle shot (FLASH) MR imaging using gadopentetate dimeglumine (Gd-DTPA) to assess the extent of pancreatic cancer.

Breath-hold 3DFT-FLASH MR images (20/4; 25° flip angle; 7 partitions; 3–5-mm slice thickness) were obtained before the administration of 0.1 mmol/kg of Gd-DTPA, just after (early phase), and 1 and 2 min (late phases) after in 14 patients with pancreatic cancer. All patients underwent surgical removal or laparotomy. We compared the findings of T1-, T2-, and postcontrast T1-weighted spin-echo (conventional SE) and 3DFT-FLASH imaging with histologic or surgical findings.

Dynamic MR images could delineate the pancreatic tumors more clearly than the conventional SE images, and were useful for diagnosing vessel invasion. The contrast-to-noise ratio between the pancreatic cancer and the surrounding pancreatic parenchyma was significantly higher with the dynamic 3DFT-FLASH image than with the conventional SE images (p<0.01).

Dynamic 3DFT-FLASH MR imaging with Gd-DTPA is useful in delineating and evaluating the extent of pancreatic cancer.

The objective of this study was to identify the factors affecting the visualization of regenerating nodules in cirrhotic liver by MR imaging.

MR images from patients with liver cirrhosis and normal subjects were studied, and signal intensity within the liver was measured and correlated with histologic findings. A reference phantom was also used as a standard.

The signal intensity of the liver on T2-weighted (T2WI) spin-echo (SE) images was significantly increased in patients with liver cirrhosis. Multiple ring-like or reticular high-intensity areas (RHAs) were demonstrated on T2WI SE images in 44 of 125 cirrhotic livers. Histologic examination in 44 cases revealed various degrees of inflammatory changes in fibrous septa surrounding regenerative nodules in all specimens, vascular dilation in fibrous septa in 4 specimens, and no hemosiderin deposition in some specimens. The results of linear discriminant analysis showed that inflammatory changes in fibrous septa were significantly more pronounced in cases with RHAs on MR.

RHAs seen on T2WI SE images may correspond to fibrous septa with inflammation. The signal intensity of fibrous septa surrounding regenerative nodules on T2WI SE images may be increased in liver cirrhosis due to inflammation or vascular dilation, contributing to the visualization of regenerating nodules as relatively low-intensity regions on MR.

To test the clinical usefulness of computed radiography (CR) with a storage phosphor plate in upper gastrointestinal radiographic examinations, a newly devised phantom gastric mucosa was used.

Simulated small elevated and depressed lesions were created on a phantom gastric mucosa made from a styrofoam “plate”. Twenty-four sets of each CR and screen-film radiographs (SR) were obtained using phototimed exposures. Receiver operating characteristic (ROC) study and visual ranking using these images were performed.

There was no significant difference between the ROC curves of CR and SR. By visual ranking, CR was equal to or better than SR in most cases. In no case was SR definitely superior to CR.

CR can be safely applied in upper gastrointestinal roentgenologic examinations.

The aim of our prospective study was to determine the diagnostic accuracy of MR mammography (MRM) in detecting malignant disease.

In 231 consecutive patients scheduled for surgery because of mammographic or palpable lesions suspected of malignancy, the breasts were examined with T1-weighted transversal images using a 3-D fast low angle shot (FLASH) sequence. One pre- and 2 post-contrast images were obtained. Histological examination of the surgical specimens showed carcinoma in 155 breasts, of which 138 were invasive and 17 in situ.

MRM detected 144 of the 155 malignancies and was false-negative in 11 cases. Eight of these MRM-missed tumours were invasive and 3 were in situ cancers. Benign lesions were found at microscopy in 95 breasts, of which MRM correctly diagnosed 69. The cellular composition of the 26 false-positive lesions (myxomatous stromal change, high vascularity, and epithelial or apocrine hyperplasia) might explain the false positivity. The sensitivity and specificity of MRM were 93% and 73%, respectively.

MRM should be interpreted with caution, and supplemented with e.g. mammography and ultrasonography.

Microcirculatory disturbances may be responsible for some of the adverse effects induced by contrast media. The influence of iopromide 370 (Ultravist) on cutaneous microcirculation was therefore investigated in 15 patients in a prospective study. Twenty ml of iopromide and 20 ml 0.9% NaCl were injected as reference in the subclavian artery at the beginning of a diagnostic coronary angiography. Erythrocyte velocity was measured in ipsilateral nailfold capillaries at the beginning of, during, and after the injection continuously up to 6 min after injection.

On average, 30 s after injection of contrast medium, erythrocyte velocity decreased significantly by 51.3% (p<0.0001) and remained reduced up to 120 s. This reaction was observed in 14 out of 15 patients. Three patients showed a temporary cessation of capillary blood flow.

The adverse effects sometimes seen during coronary angiography can be explained if similar contrast medium induced microcirculatory disturbances in the myocardial vasculature.

In 120 patients in a double-blind, randomized, parallel study, iodixanol (Visipaque), a nonionic dimer isotonic with blood, was compared with ioxaglate (Hexabrix), an ionic low-osmolar dimer, in coronary angiography regarding early and late adverse reactions. Haemodynamic and electrophysiologic parameters were also analyzed.

Visipaque resulted in significantly fewer early adverse contrast medium-related reactions (p<0.05). Visipaque also demonstrated significantly fewer effects on electrophysiologic parameters. Both contrast media reduced systolic and diastolic blood pressures at the 1st injection in the left coronary artery. Late adverse reactions were unusual with both contrast media and occurred only as urticaria with a frequency of 1.7%, which is lower than reported in i.v. studies. One serious adverse reaction, a myocardial infarction in a male patient with severe cardiovascular disease, occurred in the Visipaque group. This event was considered to be procedure- and disease-related rather than related to the type of contrast medium used.

We found Visipaque safe for coronary angiography, causing fewer early adverse reactions than Hexabrix and also fewer effects on electrophysiologic parameters. Late adverse reactions seemed to be unusual with intra-arterial administration of contrast media.

This Swedish multicenter trial was performed on patients with known or suspected lesions of the CNS for which an MR examination using a contrast medium was indicated. A total of 8 MR centers participated in the study to establish the safety and efficacy of Omniscan (gadodiamide injection) in clinical routine using a standard dose of 0.1 mmol Gd/kg b.w.

Seven hundred adult patients who had been referred for MR investigation of suspected CNS lesions were included in the study. Since most patients were examined on an outpatient basis, it was decided to use an explicit questionnaire regarding adverse events that developed within 24 h after examination. The efficacy evaluation involved comparisons of detectability, delineation, and number of lesions before and after injection of Omniscan.

No serious or unexpected adverse event was found. There were a total of 70 (10.2%) patients with adverse events, excluding those judged not to be contrast media-related. However, only 15 patients (2.2%) had adverse events that possibly or probably were related to the contrast medium. Usually, the symptoms were headache, dizziness, abnormal taste, and nausea. Two patients complained of itching, but only one developed urticaria. The efficacy was similar to that of other currently used Gd-based MR agents. Lesions were more often seen on T2-weighted images, but the contrast medium improved lesion delineation, contributing to higher certainty in diagnosis, and provided more confidence in excluding suspected abnormality.

Omniscan was found to be a safe and clinically valuable contrast medium for MR imaging of the CNS.

This experimental study was designed to investigate the effect of irradiation in prevention of intimal hyperplasia.

Twenty rabbits were divided into 4 groups, which were irradiated with 2, 5, 10, and 20 Gy, respectively. The intima of both femoral arteries was injured by air-drying, and irradiation was performed on the unilateral side. The contralateral femoral artery served as a control. Angiograms as well as histologic specimens were obtained 1 month later.

Marked intimal hyperplasia was observed in all control sites. There were no significant differences in thickness of intimal hyperplasia between irradiated and control sites in groups irradiated with 2 and 5 Gy. However, in the 10-Gy- and 20-Gy-irradiated groups, intimal hyperplasia of the irradiated site was significantly suppressed. Medial thinning and dilation of the lumen were observed in the 20-Gy-irradiated group.

Radiation may prevent intimal hyperplasia. Further investigation of the optimal dose, timing of irradiation, and long-term patency of irradiated vessels may be needed.

Small pulmonary subpleural nodules are sometimes difficult to localise at thoracotomy. With the advent of minimal invasive surgery, thoracoscopic resection avoiding anterolateral thoracotomy is an attractive procedure. Since this technique does not allow manual palpation, preoperative indication of lesions is mandatory. A simple and cost-effective system for preoperative CT-guided localisation of small subpleural nodules before thoracoscopic resection is described.

The system consists of a 0.2-mm steel wire 30–40 cm in length and a 0.9-mm biopsy needle. The tip of the wire is bent to a hook, and, guided by CT, it is placed in the vicinity of the lesion. The technique was tested in 8 cases.

The procedure was possible to perform in 7 patients. In all instances the wire remained in place when the lung was collapsed during the thoracoscopic procedure. The staple resected part of the lung also contained the lesion when examined extracorporeally.

This simple and inexpensive system was found to be useful for indication of pulmonary lesions at thoracoscopic wedge resections.

A new type of liposomal liver-specific contrast medium (CM) in CT was studied, and the results were compared with those obtained with Mn-DPDP, a paramagnetic hepatobiliary CM, in MR imaging. The contrasts of normal liver tissue to tumorous tissue and the importance of the CM for tumour detection in the 2 modalities were studied in a rabbit tumour model. CT and T1-weighted pre- and postcontrast and T2-weighted MR images precontrast were obtained.

Compared to precontrast images, significantly higher contrasts of normal liver tissue to tumorous tissue were obtained after CM administration in both CT and MR examinations. At radiologic evaluation, significantly more tumours were detected after CM administration in CT and in T1-weighted MR images than in precontrast images in CT and T1-weighted MR. There were no significant differences in tumour detection frequency in MR studies including a T2-weighted pulse sequence, postcontrast CT, or postcontrast T1-weighted MR imaging.

The use of liver-specific CM improves visualization of liver tumours in CT and T1-weighted MR imaging.

To evaluate the diagnostic value of contrast-enhanced US with CO₂ microbubbles (EU) for HCCs. Detectability was compared with DSA, dynamic CT, and Lipiodol CT.

Forty-seven histologically proven HCCs detected with US were evaluated with EU, DSA, and dynamic CT. In 23 patients (35 lesions), Lipiodol CT was also performed. The size of the tumors ranged from 8 to 71 mm (average 28.1 mm); 24 lesions were smaller than 20 mm and 23 lesions were larger than 20 mm.

Overall detection was possible in 40 of 47 lesions (85%) by EU, in 32 of 47 (68%) by DSA, in 33 of 47 (74%) by dynamic CT, and in 27 of 35 (77%) by Lipiodol CT. In tumors smaller than 20 mm, detection was possible in 21 of 24 lesions (88%) by EU, 14 of 24 (58%) by DSA, 14 of 24 (58%) by dynamic CT, and 11 of 17 (65%) by Lipiodol CT.

EU has significant diagnostic value for detection of HCCs, particularly tumors smaller than 20 mm.

Our aim was to describe the radiographic features of lobar agenesis of the liver.

Six patients with lobar agenesis of the liver, 5 right- and one left-sided, are presented. CT was used to confirm diagnosis. Chest radiography, barium meals, and urograms were also analyzed.

In right-sided agenesis, the following were observed: a) hammock or U-shaped deformity of the stomach; b) colonic interposition of the diaphragm (Chilaiditi's syndrome); and c) reversal of the cranial orientation of the colonic hepatic flexure compared to the splenic flexure. The right kidney was higher in position than the left in both right- and left-sided lobar agenesis.

Our radiographic findings can provide a multidisciplinary approach in the identification of this anatomic anomaly.

The aim of this study was to analyze the clinical efficacy of metal stents in the palliation of malignant obstructive jaundice.

Fifty patients with malignant biliary obstruction were palliated by means of drainage with a metallic self-expandable stent (Wallstent). Nineteen patients had pancreatic carcinoma, 22 cholangiocarcinoma, 4 hepatocellular carcinoma, and the remaining 5 metastatic carcinoma from a variety of primary sites. The obstruction was at the level of the liver hilum in 19 cases, in the middle common bile duct in 11, and in the lower common bile duct in 20.

The patients were followed over a period of 1–17 months. A total of 36 patients (72%) died; 14 (28%) survived. The mean observation time for the whole group of 50 patients was 3.3 months. The 30-day mortality rate was 14% (7 patients). Short-term complications occurred in 6 patients (12%). Long-term complications included stent occlusion requiring a 2nd intervention in 2 patients (4%), and cholangitis in 2 patients (4%). Excellent palliation was achieved in most of the patients. No stent migration was observed.

The metallic stent provides good palliative drainage, and the percutaneous insertion of metallic stents is well tolerated by the patients. The procedure is simple and safe to use and can be executed in one stage. The one-stage procedure, compared to the 2-stage procedure, may reduce hospital stays.

The aim of this work was, firstly, to compare different manufacturer-provided MRA sequences in a 1.0 T MR unit, with respect to the visibility of an artificial stenosis in a flow phantom and, secondly, to evaluate the same sequences in healthy volunteers with respect to S/N ratio levels and practical in vivo implementation routines.

The studied sequences were 2D and 3D TOF and sequences with an acquisition time of approximately 10 min. Quantitative signal evaluation was made using single transverse partitions in all phantom experiments. MIP angiograms and MPR reconstructions were made for visual inspection of image quality. In vivo, the images were individually evaluated by visual inspection by experienced neuroradiologists.

In the evaluation of the grade and length of a stenosis, a combination of MIP and MPR was seen to be the optimal and necessary procedure. A shortening of TE played an important and significant role in the visualization of the poststenotic flow in the phantom using TOF MRA. However, the shortest TE values gave poor S/N ratio in vivo. The good results achieved in the phantom studies for 3D phase-contrast were somewhat reversed in the volunteer studies, whereas 3D TOF sequences showed good results in both the phantom and the volunteer studies.

We wanted to compare the metabolite status of brain lesions in different clinical subtypes of multiple sclerosis (MS). Two acute MS lesions with ringlike appearances were also investigated.

Twenty-three clinically stable MS patients, 2 patients with acute relapses, and 15 healthy individuals were examined by MR imaging and localized proton MRS.

No metabolite differences were seen in plaques of different subtypes. Decreased NAA/Cr and NAA/choline ratios as well as increased inositol/Cr ratios were observed in the plaques of the clinically stable or chronic active MS patients as compared with controls. The ring plaques had hyperintense cores with surrounding halos, separated from the cores by rings with low signal intensity in T2-weighted images. The core exhibited a prolonged T2 relaxation time. Proton spectra initially contained lactate.

No differences between the metabolite status of nonacute plaques in different clinical subtypes could be detected. The ring plaques contained lactate signals indicating oedema, inflammation, and macrophage invasion, and may be transition forms between acute oedematous lesions and chronic demyelinated plaques.

The purpose of this study was to examine the potential of ³¹P-MRS (MR spectroscopy) in the pre- and postoperative evaluation of patients referred for endarterectomy.

Nine patients with unilateral, hemodynamically significant stenosis in the region of the common carotid bifurcation were examined pre- and postoperatively with CT, SPECT (regional cerebral blood flow), transcranial Doppler, and duplex sonography, and they also underwent neuropsychologic investigation. Phosphorus-31 MRS of each hemisphere was performed before and 27–148 days after surgery. The relative concentrations of phosphomono- and -diesters, inorganic phosphate, phosphocreatine, and ATP were estimated.

No definite changes in concentrations could be detected for any of the metabolites.

The lack of changes was probably due to well-functioning collaterals and to the partial volume effect, whereby changes in a focal region are hidden when larger volumes are studied.

To assess the efficacy of irradiation combined with particulate embolization for treating type D dural carotid—cavernous fistulas, supplied by the meningeal branches of both external (ECA) and internal carotid arteries.

Nine patients were treated by particulate embolization via the ECA branches, followed by radiation therapy with doses of 30 Gy. One of these patients with recurrent symptoms received an additional 30 Gy one year after initial treatment, making a total dose of 60 Gy.

In all cases, symptoms were improved immediately after the particulate embolizations. In 8 cases, complete resolution of symptoms were obtained in 4–19 months and an average of 8 months after treatment. In one case, chemosis was markedly improved and persisted minimally 41 months later.

Particulate embolization is effective for immediate symptomatic improvement, and complete resolution of symptoms can usually be achieved by subsequent radiation therapy.

To determine the association between successful intraarterial thrombolysis and the following factors: sex, age, symptoms, duration of symptoms, length of occlusion, conduit type, runoff, and catheter localization.

Forty-six patients with acute or subacute occlusions of peripheral native arteries and grafts were treated with continuous intraarterial infusion of streptokinase or urokinase. A univariate chi-square test and logistic regression analysis were used.

Successful lysis was achieved in 27 of 46 patients (59%). The logistic regression analysis revealed a significant association between successful thrombolysis and good runoff (p<0.01). A catheter position above the occlusion resulted in lysis in only one of 11 patients. The variables rest pain and claudication were slightly significant (p=0.07). None of the other variables were significant, but a trend toward a separate effect of duration of occlusion was found.

Good runoff and intrathrombotic infusion are virtual necessities in obtaining a positive immediate outcome in peripheral arterial and graft occlusions. In our study, other factors were less important.

The videoradiographic examination described was designed for habitual snorers and sleep apnea syndrome (SAS) patients and was performed during wakefulness and sleep. During wakefulness the purpose was to reveal any dysfunction in deglutition and speech as well as morphologic abnormalities. The purpose during sleep, which usually was induced by low-dose midazolam intravenously, was to reveal the site and form of obstruction in obstructive sleep apnea patients and the site of snoring in habitual snorers.

The preoperative results of 104 patients are presented. In 57 patients who had apneas, the occurrence and type of apnea could be determined.

A continuous recording over some minutes gave a rough estimate of the degree of SAS and mean duration of apnea. Although much information on SAS can be obtained by this method, it cannot replace polygraphic sleep recording in the investigation of habitual snorers and SAS patients. However, these 2 methods are complementary and can be performed simultaneously as polygraphic videoradiography.

We attempted to determine the usefulness of high-speed MR imaging for evaluating the severity of sleep apnea syndrome (SAS) by comparing findings of pharyngeal obstruction obtained with high-speed MR with those of all-night polysomnography (PSG).

A total of 33 patients with SAS underwent turbo-FLASH MR examination, while awake and after i.v. injection of hydroxyzine hydrochloride. Serial images were examined by cinemode. Pharyngeal findings on MR were divided into single-site obstruction (SO) at the velopharynx, multiple-site obstruction (MO), and no obstruction (NO). PSG findings were analyzed to determine the predominant type of apnea, severity as evaluated by an apnea index (AI), and the lowest SaO₂ value during sleep.

Seventy-five percent of the central apnea group had SO, and 70% of the mixed apneas had MO, while only 15% of the obstructed apneas had MO. The percentage of patients with severe SAS (AI of 20% or higher) was 48% for the SO, and 70% for the MO. The lowest SaO₂ value tended to be low in the mixed apnea in the case of PSG, and tended to be low in the MO at MR examination.

Analysis of pharyngeal dynamics using high-speed MR may provide some useful information for evaluating the severity of SAS.

Long-term follow-up of residual mediastinal masses in treated Hodgkin's disease using MR imaging.

Ten patients, with substantial residual mediastinal masses of low signal intensity (SI) in the T2-weighted image (T2WI), were reinvestigated with MR 19–79 months after completing treatment of Hodgkin's disease. All patients were in complete remission.

During the follow-up period, the masses had decreased in size by 0–95% (median 67%) as compared to their initial post-therapy size. The SI continued to be low in the T2WI and was unaffected by the degree of size reduction.

It is speculated that these mainly fibrotic residual masses undergo slow degradation of the fibrotic part and/or resorption of remaining inflammatory tissue. It is important to understand the natural, long-term MR imaging changes of these residual masses in order more easily to recognize tumour recurrence or other pathologic conditions.

Evaluation of diagnostic accuracy and complication frequency at ultrasonographically guided fine-needle aspiration biopsy of intrathoracic tumors.

A total of 134 ultrasonographically guided percutaneous fine-needle aspiration biopsies were performed on 128 patients with intrathoracic tumors abutting on the pleura. A cytologic diagnosis was obtained in 119 patients (93%).

In 83 patients, cytologic malignancy was found; in 34, benignity; and in 2, cellular atypia. A total of 117 diagnoses were correct and 2 diagnoses were false-positive. A malignancy subtyping based on the cytologic aspirates was made in 80 patients. In 40 (93%) of 43 histologically proven subtypes, the subtyping was correct. The complication frequency in terms of pneumothorax was 3.7%.

Ultrasonographically guided percutaneous fine-needle aspiration biopsy is a safe and reliable method of establishing the cytologic diagnosis of intrathoracic tumors.

Chest radiographs from 3 digital systems − 2 based on luminescent phosphors and one on selenium — and a conventional film-screen system were evaluated and compared.

Computed radiography (CR) has for the past years been dominated by a single manufacturer, but now several systems have been marketed. Using a chest phantom and, as test objects, 2 simulated tumours for the lung and mediastinum, respectively, and one object simulating pulmonary lines, a total of 400 exposures were made, 100 on each system. The test objects were placed randomly with a ratio of presence/absence of each object of about 50. Six radiologists participated, 2 residents and 4 staff members. A receiver operating characteristics (ROC) analysis was performed with construction of curves, and the difference between the curves was estimated with a 2-tailed paired t-test.

The selenium-based system performed significantly better for pulmonary line detection than all the other systems, and better than one storage phosphor system for the lung “tumour” (p<0.05), while one storage phosphor system was slightly better than the other in diagnosing all 3 test objects. The score for the film-screen system was only average.

Investigation of examination technique, image quality, and absorbed dose to the patients in paediatric radiology.

In total, 19 Swedish hospitals participated in the study. Using a questionnaire, the hospitals described their examination technique for the pelvis, urinary tract, colon, scoliosis, and lung. The image quality and patient dose were experimentally studied for the simulated pelvis examination of a 1-year-old child. This examination was carried out with a test object containing a contrast-detail phantom. TL dosimeters were used to determine the absorbed dose on the surface of the phantom, approximately corresponding to the absorbed dose on the surface of the patient.

Examination techniques varied considerably among the hospitals, the most striking difference concerning the film-screen sensitivity. Consequently, there was a variation in the absorbed dose on the surface of the phantom, from 0.09 mGy to 1.7 mGy (mean 0.65 mGy). For a large range of doses, 0.4–1.7 mGy, the image quality was not significantly different.

The unharmonized, and in many places unoptimized, examination techniques led to a great variation in the absorbed dose to the children examined.

To estimate the prevalence of adrenal expansive lesions in patients with bronchial carcinoma, and assess the relationships among adrenal masses, TNM classification, and histology of the bronchial carcinoma, and to reveal other signs of inoperability in these patients.

CT findings of the thorax and upper abdomen in 96 patients with bronchial carcinoma were reviewed. Brain- and upper abdominal metastases, together with TNM classification and histology of the bronchial carcinoma, was recorded. CT was performed with 10-mm slice thickness from the thorax aperture to the renal hilum under i.v. contrast medium injection.

Eight adrenal expansive lesions (1.5–10 cm, mean 4.6 cm) were revealed in 6 of the 96 patients (6.3%). Two of these patients, classified as N0, had metastases in other organs; one had brain metastases and the other liver metastases. The bronchial carcinomas in the remaining 4 patients were classified as N3. Three of the patients had adenocarcinoma, one each of small-cell-, large-cell-, and unclassified bronchial carcinoma. Squamous cell carcinoma was most common in the total patient population, but no patient with adrenal masses showed this histologic type.

The finding of adrenal expansive lesions in bronchial carcinoma has little clinical impact, because these patients usually show other signs of inoperability. Hence, the value of upper abdominal CT as a routine examination is questionable.

To examine the relationship between focal renal cortical retention (FRCR) and contrast-associated nephropathy (CAN).

We investigated the incidence of both phenomena in 105 patients. CAN was defined as an increase in the creatinine level >0.3 mg/dl and >20% on days 1, 3, or 7. We compared predisposing factors for FRCR and CAN. Serum creatinine and blood urea nitrogen (BUN) for renal function were determined on the morning of the day of the angiography. The BUN/creatinine ratio was used as an indicator of the degree of hydration.

FRCR was demonstrated in 17 patients (16%) by delayed CT 24 h after angiography, and CAN was found in 16 patients (15%). No significant relationship between CAN and FRCR was found. We found a correlation between high total volumes of contrast and FRCR. Advanced age, high blood urea nitrogen, high creatinine, and dehydration were risk factors for CAN.

Delayed CT showed a higher incidence of injury to the renal parenchyma than previously detected by conventional radiography.

We attempted to assess objectively the response of Peyronie's disease plaques to local interferon-α2B.

Twenty patients were treated with 5 local injections of 1 million units of IFN-α2B into a single designated plaque. Before treatment, and 4 weeks and 6 months after treatment, the plaques were examined ultrasonographically. Each time, a histogram profile was performed. All patients also underwent soft-tissue radiography in 2 planes using the mammography technique before and 6 months after treatment.

We found that with ultrasonography the plaques could be classified into 3 groups depending on degree of calcification, from nil to complete. Radiography detected calcifications better than ultrasonography but failed to detect plaques without calcification. The degree of calcification was negatively correlated with the response to treatment, since noncalcified plaques responded best, while fully calcified plaques failed to respond.

In Peyronie's disease, ultrasonography is an important tool for non-invasive monitoring treatment response and for preselecting patients for medical treatment.

To describe the changes in the endosonographic appearance of the anal sphincter muscles with age.

Fifty subjects (age range 22–85 years) with no history of anorectal disease or surgery were studied with anal endosonography. The thickness of the internal and external anal sphincter was registered and correlated to age. For the internal sphincter, which is often asymmetric, the maximum and minimum thicknesses were measured at any part of the circumference (except anteriorly for anatomic reasons) and also in the lateral positions.

A significant positive correlation with age was found for all maximum, minimum, and average internal sphincter thicknesses. Moreover, the echogenicity of the internal sphincter changed with age as the sphincter muscle became more echogenic. There was no significant correlation between external sphincter thickness and age.

Knowledge of the normal variation of the internal sphincter thickness with age is important since endosonography may be used to identify patients with hypertrophy of the internal sphincter. Currently, we consider maximal thicknesses above 4 mm to be abnormal in patients under 50 years of age, whereas in patients aged at least 50 years thicknesses of 5 mm or more are considered abnormal.

To characterize the CT findings of dermatofibrosarcoma protuberans.

CT and pathologic specimens of 6 patients with dermatofibrosarcoma protuberans (5 in the trunk and 1 in the leg) were retrospectively reviewed.

CT clearly defined the tumors in the dermis and subcutaneous tissue with a characteristic, if not pathognomonic, protrusion. On postcontrast CT, 3 tumors showed marginal enhancement and central low density, while the others showed homogeneous enhancement. Pathologically, the marginal enhancement on CT corresponded to fibrosarcomatous changes, and the central low density to necrosis. The tumors with homogeneous enhancement had no sarcomatous changes.

CT allows detection and precise anatomic localization of dermatofibrosarcoma protuberans. Marginal enhancement with central low density on CT may suggest a relatively poor prognosis.

Contrast-enhanced MR imaging of the spine after surgery for lumbar disk herniation almost always shows pathologic changes. To investigate to what extent these changes are correlated to patients' actual clinical symptoms, we compared the postoperative MR findings in 19 asymptomatic patients with 42 symptomatic patients (43 levels).

The asymptomatic patients underwent MR examination one year after surgery. Twenty-six of the symptomatic patients underwent MR one year or less after surgery, and in 16 patients (17 levels) MR was performed more than one year after surgery.

Sixteen percent of the asymptomatic and 42% of the symptomatic patients had disk herniation at the level of previous surgery. Most of the herniated disks were found in the symptomatic patients less than one year after surgery. The amount of epidural scar tissue, displacement and thickening of nerve roots, and compression of the dural sac were also studied. Disk herniation as a probable cause of recurrent sciatica was a common finding among symptomatic patients examined one year or less after surgery. In comparing asymptomatic patients and symptomatic patients with more than one year between surgery and MR examination, no significant radiologic differences, including disk herniation, were found.

To evaluate the effects on cost, and number of primary and supplementary neuroradiologic examinations, after introducing MR imaging as the primary modality in the evaluation of the lumbar spine.

Two 5-month periods were compared: period 1 — before MR; and period 2 — after introduction of a 2nd MR device. In period 1, patients were examined with myelography and/or CT after referral from specialists only, whereas in period 2 both specialists and general practitioners could refer patients for MR imaging. The direct cost (neuroradiologic methods and hospitalization) and indirect cost (sick-leave and estimated loss of production caused by the diagnostic procedure) were estimated.

In period 1, investigations were started in 75 patients (62 myelographies and 13 CT examinations); in period 2, in 227 patients (198 MR, 21 CT, and 8 myelographies). The estimated total cost increased from SEK 825 000 to 1 265 000 (53%), the cost per investigated patient decreasing from 11 000 to 5565 (50%), and the cost of preoperative investigation per operated patient decreasing from 8616 to 5563 (35%). The number of supplementary examinations was unchanged.