Acta Radiologica

Purpose: To evaluate the results of radiofrequency ablation (RFA) therapy with regard to long-term survival and rate of complications in patients with liver metastases from colorectal carcinoma.

Material and Methods: A total of 102 patients were included and treated with RFA. In 100 patients, resection was not possible; two patients refused surgery. The patients had a total of 332 colorectal liver metastases. Pre- and post-treatment evaluation was performed with contrast-enhanced computed tomography. Survival from time of diagnosis of liver metastases was calculated by Kaplan-Meier analysis. Complications were recorded as minor or major in accordance with the definitions of the Society for Cardiovascular and Interventional Radiology.

Results: Estimated median survival from time of diagnosis of liver metastases was 52 months (95% CI 34–82). Estimated 1-, 2-, 3-, 4-, and 5-year survival was 96%, 79%, 64%, 52%, and 44%, respectively. Minor complications were recorded following seven RFA treatments (4.0%) and major complications following 12 RFA treatments (6.9%).

Conclusion: RFA is an effective method to treat liver metastases from colorectal carcinoma. Survival is improved and comparable with survival following surgical resection. The rate of complications is low.

Purpose: To estimate the cost-effectiveness of detecting colorectal polyps with computed tomographic colonography (CTC) and subsequent polypectomy with primary colonoscopy (CC), using CC as the alternative strategy.

Material and Methods: A marginal analysis was performed regarding 103 patients who had had CTC prior to same-day CC at two hospitals, H-I (n = 53) and H-II (n = 50). The patients were randomly chosen from surveillance and symptomatic study populations (148 at H-I and 231 at H-II). Populations, organizations, and procedures were compared. Cost data on time consumption, medication, and minor equipment were collected prospectively, while data on salaries and major equipment were collected retrospectively. The effect was the (previously published) sensitivities of CTC and CC for detection of colorectal polyps⩾6 mm (H-I, n = 148) or ⩾5 mm (H-II, n = 231).

Results: Thirteen patients at each center had at least one colorectal polyp⩾6 mm or ⩾5 mm. CTC was the cost-effective alternative at H-I (€187 vs. €211), while CC was the cost-effective alternative at H-II (€239 vs. €192). The cost-effectiveness (costs per finding) mainly depended on the sensitivity of CTC and CC, but the depreciation of equipment and the staff's use of time were highly influential as well.

Conclusion: Detection of colorectal polyps⩾6 mm or ⩾5 mm with CTC, followed by polypectomy by CC, can be performed cost-effectively at some institutions with the appropriate hardware and organization.

Interpreting Trauma Radiographs. Edited by J. McConnell, R. Eyres and J. Nightingale. Oxford: Blackwell Publishing, 2005. ISBN 9781405115346. 286 pages. Price paperback: EUR 58.90.

Purpose: To determine the diagnostic accuracy and the clinical impact of ultrasound (US) and computed tomography (CT) in diagnosing appendicitis, and to evaluate the impact of laboratory tests on the treatment of acute appendicitis.

Material and Methods: All patients who, during 2005, underwent an acute ultrasound or CT investigation due to suspected appendicitis, or were diagnosed and/or surgically treated for appendicitis at Umeå University Hospital, Umeå, were included. The type of radiological investigation, its findings, the choice of treatment, final diagnosis, C-reactive protein (CRP), leukocyte particle count (LPC), body temperature, age, and sex were recorded for each patient. The histological result from surgery was considered the gold standard.

Results: The material included 305 cases with an overall appendicitis prevalence of 58%. Fifty-two percent of the patients were female. The mean age was 29 years, with a total range of 2–94 years. Twenty percent (60/305) underwent a CT investigation, 40% (123/305) underwent an US investigation, 5% (14/305) underwent both a CT and an US investigation, and 35% (108/305) of patients did not undergo any radiological investigation at all. The sensitivities and specificities were 91% and 94% for CT, and 83% and 98% for US, respectively. The positive likelihood ratio was 15.1 and 45.5 for CT and US, and the negative likelihood ratio was 0.09 and 0.18 for CT and US, respectively. It was not possible to visualize the appendix in 31% of patients examined with US. The prevalence of appendicitis in this group was the same as the prevalence among patients where it was possible to see the appendix, i.e., 35%. The mean CRP for all patients with appendicitis was 59 (95% CI 10–491) mg/l, and the mean LPC was 11.1 (95% CI 2.6–28.1) ×10⁻⁹/l. The mean LPC level was significantly higher for the appendicitis patients. Body temperature could not significantly verify or exclude appendicitis. The overall negative appendectomy rate was 9% (16/176), and it was higher in women, i.e., 11% (9/79). The negative appendectomy rate was slightly higher in the group that was examined by CT and/or US, i.e., 12% (8/69) compared to 7% (8/107) in the group not examined radiologically.

Conclusion: Diagnostic accuracy was high for US as well as for CT. US was better for diagnosing positive findings, while CT was better for excluding diagnosis of appendicitis. The diagnostic accuracy of LPC, CRP, and body temperature was low. By combining findings from the radiological examination with the results from the clinical examination and laboratory values, a low negative appendectomy rate can be achieved.

Purpose: To investigate the prevalence of renal artery aneurysms, and to assess the value of multidetector-row computed tomography (MDCT) in diagnosing renal artery aneurysms.

Material and Methods: Altogether, 862 patients underwent arterial-phase contrast-enhanced CT scan of the abdomen in the period November 2003 to October 2005. A search for renal artery aneurysms was performed in our reporting system and revealed six patients with renal artery aneurysm (RAA).

Results: The incidence of RAA was 0.7%. All renal artery aneurysms were solitary, located in the main trunk or the first branch of the renal artery, with sizes from 1.5 cm to 3.4 cm. Five aneurysms were saccular, one fusiform. No underlying thrombosis was seen. Extensive calcification was found in one aneurysm. Three aneurysms were diagnosed using axial images, while three aneurysms were only displayed by volume rendering and maximum-intensity projection images.

Conclusion: This study demonstrates a 0.7% incidence of renal artery aneurysms in a total of 862 patients. MDCT has an important role in detecting and assessing renal artery aneurysms. Some aneurysms can only be displayed by post-processing techniques such as volume rendering and maximum-intensity projection.

Purpose: To retrospectively evaluate results of selective embolization of the accessory left gastric artery prior to repeated hepatic arterial infusion chemotherapy using a port-catheter system.

Material and Methods: Of 22 patients with unresectable advanced liver cancer who underwent percutaneous implantation of a port-catheter system, an accessory left gastric artery was revealed by arteriography in 16 patients before and in six patients after port-catheter implantation. The right gastric artery was embolized to prevent gastric mucosal lesions in all 22 patients. In addition, the accessory left gastric artery was selectively embolized for the same purpose using from one to six microcoils, which were from 3 to 5 mm in diameter. Within 10 days after implantation, arteriography was performed while contrast material was infused via the port.

Results: Selective embolization of the accessory left gastric artery was successful in all 22 patients. No complication related to embolization of this artery occurred in any patient. A gastrointestinal mucosal lesion developed in only one case during hepatic arterial infusion chemotherapy, but was unrelated to the accessory left gastric artery.

Conclusion: Prophylactic embolization of the accessory left gastric artery is useful to avoid development of a gastrointestinal mucosal lesion resulting from hepatic arterial infusion chemotherapy.

Ultrasound of the Urogenital System. Edited by G. M. Baxter and P. S. Sidhu. Stuttgart: Thieme Medical Publishers, 2006. ISBN 1588902374. 276 pages, 450 illustrations. Price hardcover: EUR 109.95.

Purpose: To evaluate the impact of exactness of the segmentation of the left ventricle (LV), using cine magnetic resonance imaging (MRI).

Material and methods: Steady-state free-precession cine MRI was performed on 100 randomly selected subjects. Myocardial borders were outlined on short-axis images using three methods: method 1 was computer assisted, excluding papillary muscles from the left ventricular mass (LVM); method 2 was similar but included papillary muscles; and method 3 was manually traced including papillary muscles. LV end-systolic (ES) and end-diastolic (ED) masses and volumes, ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were calculated from these measurements. The difference between the ES and ED LVM was used to estimate the exactness of the methods.

Results: Method 3 was the most exact, and method 1 was the least exact. The three methods generated differing EF, SV, and CO measurements. With an ES–ED LVM difference exceeding 20 g, the mean SV measurement error was 8.8±3.6 ml.

Conclusion: Manual tracing proved more exact than computer-assisted quantification. Exactness had an impact on EF, SV, and CO measurements, and the ES–ED LVM difference can be used to identify assessments that would benefit from more exact segmentation.

Purpose: To examine how a one-time bolus injection of radiographic contrast media (RCM; iodixanol 320 and iomeprol 350) into the left coronary artery of six pigs affects tissue oxygen tension in the artery's supply area (pO₂ LAD) compared to a 0.9% sodium-chloride (NaCl) bolus.

Material and Methods: Each animal received a total of three boluses: one iodixanol, one iomeprol, and one NaCl (10 ml each). The radiographic contrast media and NaCl boluses were randomly assigned, and pO₂ profiles were recorded.

Results: 26.7±16.4 s after iodixanol injection, pO₂ LAD had declined by 3.5% from 42.2±5.6 mmHg to 40.7±5.9 mmHg (P = 0.0357). After 53±16.7 s, the initial value was restored. The pO₂ LAD was 41.9±7.4 mmHg before iomeprol injection, and, 303.3±58.9 s after injection, pO₂ LAD had declined by 13.1% to 36.4±7.5 mmHg (P = 0.0001). After 577±22 s, the initial value was restored. The bolus application of an isotonic NaCl solution resulted in no effect on pO₂ LAD. Immediately after injection, it increased by 3%. In the supply area of the right coronary artery and the peripheral skeletal muscle, no effect of the RCM or NaCl on tissue oxygen tension was observed. Furthermore, no effect on tissue temperature, heart rate, systolic and diastolic blood pressure, or cardiac output per minute occurred.

Conclusion: The injection of RCM in a coronary artery can result in a significant local contrast-medium-induced microcirculation disorder. The high viscosity of iodixanol led to a very short-term insignificant effect on the microcirculation, while iomeprol induced a slight time-delayed pO₂ decrease, which might be caused by the rigidification of erythrocytes. In comparison to a previous study with iopromide, the influence of iodixanol and iomeprol on myocardial oxygen tension was markedly less pronounced.

Purpose: To evaluate the value of 64-detector-row computed tomography for ruling out high-grade coronary stenoses in patients with a low to moderate pretest probability of significant coronary artery disease.

Material and Methods: The study included 61 patients with a suspicion of coronary artery disease on the basis of atypical angina or ambiguous findings in noninvasive stress testing and a class II indication for invasive coronary angiography (ICA). All patients were examined by 64-detector-row computed tomography angiography (CTA) and ICA. On a coronary segmental level, the presence of significant (⩾50% diameter) stenoses was examined.

Results: In a total of 915 segments, CTA detected 62 significant stenoses. Thirty-four significant stenoses were confirmed by ICA, whereas 28 stenoses could not be confirmed by ICA. Twenty-two of them showed wall irregularities on ICA, and six were angiographically normal. Accordingly, on a coronary segmental basis, 28 false-positive and 0 false-negative findings resulted in a sensitivity of 100%, a specificity of 96.8%, a positive predictive value of 54.8%, and a negative predictive value of 100%. The diagnostic accuracy was 96.9%.

Conclusion: Sixty-four-detector-row computed tomography reliably detects significant coronary stenoses in patients with suspected coronary artery disease and appears to be helpful in the selection of patients who need to undergo ICA. Calcified and non-calcified plaques are detected. Grading of stenoses in areas with calcification is difficult. Frequently, stenosis severity is overestimated by 64-detector-row computed tomography.

The Chest X-Ray: Differential Diagnosis in Conventional Radiology. Second edition. Edited by A. F. Burgener, M. Kormano and T. Pudas. Stuttgart, New York: Thieme Verlag, 2006. ISBN 1-58890-446-6 (TNP New York), ISBN 3-13-107612-7 (GTV Stuttgart). 208 pages, 329 figures, 29 tables pages. Price hardcover: EUR 79.95. USD 99.95

Purpose: To determine the in vivo precision and accuracy of magnetic resonance imaging (MRI) in evaluating the thin (˜mm) femoral neck cortex.

Material and Methods: Hip regions of 30 volunteers were scanned with standard 1.5T MRI twice with repositioning, and the images of the narrow-neck cross-sections were obtained. Two radiologists independently delineated periosteal and endosteal cortical boundaries, and several structural variables were determined. For precision, 95% limits of agreement and coefficients of variation were calculated. Accuracy was determined with phantoms.

Results: In vivo precision of the directly delineated measurements varied from 0.9% (periosteal circumference) to 1.6% (total area), while the precision of the calculated variables remained poorer, from 7.3% (cortical to total area ratio) to 15.1% (torsional rigidity). The root-mean-square error of the cortical thickness measurement was 0.15 mm.

Conclusion: Thin cortical bone at the narrowest location of the femoral neck can be delineated precisely and accurately with a standard clinical 1.5T MRI device. MRI provides a feasible tool for the assessment of mechanically important cortical bone at the femoral neck and may be of clinical utility in assessing hip fragility.

Purpose: To find magnetic resonance (MR) findings predicting cement leakage in patients receiving percutaneous vertebroplasty (PVP) due to osteoporotic compression fractures.

Material and Methods: MR was done in 43 patients (age 52–89 years) before PVP (56 vertebrae), which was done via a bipedicular approach with fluoroscopic monitoring. Shortly after the procedure, a non-contrast-enhanced computed tomography (CT) scan was done at the vertebroplasty sites for evaluation of bone cement leakage. The following MR findings of fractured vertebral bodies were retrospectively reviewed for correlation with leakage risk: severity of bone-marrow edema, presence of a T2-weighted low-signal-intensity line, percentage residual vertebral body height, presence of either a vacuum or cystic change within the vertebral body, and presence of a cortical disruption.

Results: After PVP, cement leakage was detected in 35 vertebrae (62.5%). Leakage was most frequently observed in the anterior external vertebral venous plexus (46%). Cement leakage rate increased when there was a cortical disruption (P = 0.037), especially at the endplates, while it decreased when there was a vacuum or a cystic change within the fractured vertebra (P = 0.019). Other MR findings were not related to the risk of cement leakage.

Conclusion: The risk of cement leakage in PVP increases when MR shows cortical disruption in a fractured vertebral body, especially at the endplates. It decreases when MR shows a vacuum or cystic change within the body.

Purpose: To report the feasibility of using ethylene vinyl alcohol copolymer (EVAC) for embolization of lower-falx meningiomas.

Material and Methods: Three patients were treated. The procedures were done under general anesthesia. A terminal branch of the middle cerebral artery in the proximity of the tumor was catheterized as near as possible or into the pre-falcine arterial anastomotic network around the superior sagittal sinus, and embolization with EVAC was performed with a standard injection technique.

Results: This technique resulted in filling of the tumor-supplying dural arteries including all collaterals from both sides, filling of the dural territory of the tumor circulation, and some obliteration of the tumor's pial supply. On later operation, the tumors could be removed from the inside out with minimal brain retraction.

Conclusion: Effective preoperative embolization of lower-falx meningiomas using EVAC is feasible. This technique has a sound anatomical basis, and it can be used with benefit even in falx meningiomas with predominantly pial vascular supply.

Purpose: To investigate the potential value of magnetic resonance elastography (MRE) in evaluating the consistency of brain tumors.

Material and Methods: Six patients with known solid brain tumor underwent brain MRE studies. Consistency of brain tumors was evaluated at surgery. Correspondence of MRE evaluation with operative result was studied.

Results: The elasticity of tumors in six patients evaluated by MRE agreed with the tumor consistency given by the operative results.

Conclusion: MRE could be used as an imaging technique for noninvasive assessment of the consistency of brain tumor in vivo.

Sinus histiocytosis with massive lymphadenopathy (SHML), or Rosai-Dorfman disease, is a rare histiocytic disorder that typically presents with chronic, self-limiting cervical lymphadenopathy. Although this disease mainly affects histiocytes, there are a few reports of bone marrow infiltration. Diffusion-weighted imaging (DWI) is a promising technology in differentiating between various bone marrow pathologies. We here present conventional magnetic resonance imaging and DWI features of a patient with SHML and bone marrow involvement.

Purpose: To evaluate cerebral hemodynamic disturbance in patients with symptomatic unilateral middle cerebral artery (MCA) high-grade stenosis or occlusion using dynamic susceptibility contrast perfusion magnetic resonance imaging (DSC-pMRI).

Material and Methods: DSC-pMRI was performed in 28 patients with symptomatic unilateral MCA high-grade stenosis or occlusion. Hemodynamic parameters including relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV), relative mean transit time (rMTT), and time to peak (TTP) were calculated and compared between the stenosed or occluded side and contralateral side. Seven of the 28 patients underwent surgery or interventional therapy, and hemodynamic changes between pre- and post-therapy were investigated.

Results: Prolonged rMTT and TTP were found in the stenosed or occluded MCA territories in all 28 patients. Significant differences were found in rCBV (P<0.05), rMTT (P<0.001), and TTP (P<0.001) between the stenosed or occluded side and the contralateral side. However, no significant difference was observed in rCBF (P>0.05). In the seven patients with surgical or interventional therapy, the values of rMTT and TTP significantly decreased after surgery or interventional therapy (P<0.001).

Conclusion: DSC-pMRI may be a useful tool for evaluating and monitoring cerebral hemodynamic disturbance in patients with symptomatic unilateral MCA high-grade stenosis or occlusion.

This short communication presents significantly increased permeability in two patients with acute stroke, indicating an early blood–brain barrier disruption. Neither of the patients had undergone any thrombolytic therapy and hemorrhaged later. Increased permeability was assessed in both patients using a distributed-parameter model of capillary-tissue exchange. Our findings indicate that early physiologic imaging in stroke may identify patients with a high risk of hemorrhagic transformation by revealing pathologic vascular changes and, thus, guide therapeutic options.

Nephropathia epidemica (NE) is a mild form of hemorrhagic fever with renal syndrome (HFRS). Its course varies from asymptomatic to fatal. The etiologic agent, Puumala virus, belongs to the Hantavirus genus of the Bunyaviridae family. Respiratory symptoms, from common cold to respiratory distress, occur in NE. Acute renal failure (ARF) is evident in over 90% of hospital-treated NE patients. In this review article, special attention is paid to radiological lung and renal involvement to investigate the occurrence and type of manifestations during the acute phase of infection and recovery.

Purpose: To retrospectively evaluate the long-term results of transcatheter arterial embolization for high-flow priapism.

Material and Methods: The study comprised six patients with high-flow priapism treated by superselective embolization of the internal pudendal arteries at our institution. The cause of priapism was traumatic in five patients and idiopathic in one. Follow-up was⩾5 years in all cases.

Results: A total of nine embolizations were performed in the six patients. Embolization was performed once in three patients, while repeated embolizations were performed in the remaining three. Eleven arteries were altogether treated. Embolic materials used were gelatin sponge in nine arteries, gelatin sponge and microcoils in one, and microcoils alone in one. Embolization of the internal pudendal arteries on both sides in one single session was performed in one patient. In one patient, complete occlusion of the pseudoaneurysm was not achieved. However, restoration of erectile function and detumescence were noted during follow-up. Complications during the procedure were not registered. At follow-up⩾5 years after successful embolization, all six patients experienced detumescence as well as normal erectile function.

Conclusion: Superselective embolization of the internal pudendal artery is the procedure of choice for treatment of high-flow priapism.

Purpose: To evaluate the appearance, type, frequency, and clinical importance of retroaortic left renal vein (RLRV) in patients examined with multidetector computed tomography (MDCT) angiography.

Material and Methods: A total of 1856 patients who underwent CT with urological symptoms (hematuria, flank and abdominal pain, left gonadal vein varicocele) (n = 889) or with symptoms other than urological ones (n = 967) were prospectively evaluated for the presence of RLRV. CT was performed with 110ml of iodinated contrast material through the antecubital vein at a rate of 3.5 ml/s. Late arterial and early venous phase volumetric data sets were acquired at 30 and 65 s, respectively, from the start of the intravenous injection of contrast medium. In addition to axial images, multiplanar reconstructions (MPR), maximum-intensity projection (MIP), and three-dimensional volume-rendering (3D VR) images were used to assess left renal vein anomalies. Left renal vein anomalies were classified into four types according to their appearance: I) RLRV joining the inferior vena cava (IVC) in the orthotopic position; II) RLRV joining the IVC at level L4–L5; III) circumaortic or collar left renal vein; IV) RLRV joining the left common iliac vein.

Results: RLRV was detected in 68 (3.6%) of the 1856 patients, with 26, 22, 17, and three of types I, II, III, and IV, respectively. Forty-four of the 68 patients with RLRV (65%) were in the group with urological symptoms, while 24 patients (35%) were in the group without urological symptoms. Compression of the RLRV was found in 16 patients in the urological symptoms group, while compression was detected in only three patients in the other group. This difference was statistically significant (P<0.05). The most common urological symptom was hematuria. The frequency of urological symptoms was higher in groups II and IV compared to the other groups.

Conclusion: MDCT angiography with axial, MPR, MIP, and 3D VR images is effective in the detection of vascular renal anomalies such as RLRV. Diagnosing RLRV and differentiating it from other pathologic conditions causing hematuria is important in order to avoid complications during retroperitoneal surgery or interventional procedures.