The Neuroradiology Journal

Prenatal Diffusion-Weighted Imaging (DWI) was recently demonstrated to be feasible in the normal fetal brain. We report our preliminary experience of abnormal prenatal DWI findings in the brains of eight fetuses with suspected lesions on the basis of clinical and ultrasound findings. The diffusion-weighted echo-planar sequence, which had an acquisition time of 14–18 seconds, was performed with the mother holding her breath. Slice thickness varied from 5 to 6 mm, the TR was 4000–5000 ms, the TE was 81 ms, the in plane resolution was 2.5×2.5 mm. Apparent Diffusion Coefficient (ADC) trace maps were calculated on the basis of three axes diffusion-sensitized images. In two cases, hypoxic-ischemic focal lesions showed a DWI signal compatible with the acute or subacute stage. In two cases of recent fetal death, the brain ADC was markedly decreased. In a case of fetus papyraceus, the intracranial ADC value suggested the brain having a solid structure. In a case of intraventricular hemorrhage, the lesion was more conspicuous on DWI than on conventional images. In a case of brain developmental malformations, the ADC showed values compatible with decreased cellular proliferation disorders. In a case of intracranial cystic mass, DWI readily differentiated between an arachnoid and an epidermoid cyst. DWI appears to enhance the prenatal MRI capability of characterizing hypoxic-ischemic lesions. Moreover, prenatal DWI seems to provide valuable information on the timing of fetal death. ADC determination can provide additional data on the nature of brain malformations in cases of abnormal development.

In some instances conventional imaging techniques fail to differentiate meningiomas from isolated dural metastasis. This study aimed to evaluate the role of diffusion and perfusion-weighted MRI in differentiating meningiomas and dural metastasis. In this study, 14 metastasis and 26 meningiomas were involved. The imaging characteristics were analyzed using conventional MRI. Diffusion-weighted MRI was performed and ADC values were calculated from the solid components and the peritumoral edema. Perfusion-weighted MRI was performed and relative cerebral blood volume (rCBV) was calculated. Student's t test was used for the statistical analysis. Dural metastasis and meningiomas could not be differentiated by qualitative assessment of conventional and diffusion-weighted MRI. The mean intratumoral and peritumoral ADC values were not statistically significant (p > 0.05). The rCBV ratios for dural metastasis and meningiomas were 4.13 ± 2.32 and 7.32 ± 4.10 respectively and the difference between two was statistically significant (p = 0.003). Peritumoral rCBV ratios for dural metastasis and meningiomas were not statistically significant (p > 0.05). Conventional MRI findings of dural metastasis and meningiomas may overlap in some lesions. In differentiation of these lesions diffusion-weighted MRI yields no further information additional to conventional sequences. Perfusion-weighted MRI can be useful to distinguish these lesions by demonstrating high intratumoral rCBV ratios for meningiomas and low rCBV ratios for metastasis.

The purpose of this study was to evaluate the zero-filling interpolation processing (ZIP) technique for contrast-enhanced MR angiography (CE-MRA). Phantoms of arteries were made with different lumen diameters. Gadolinium-enhanced three-dimensional MR angiography was performed on a GE 1.5T scanner. The parameters of FSPGR pulse sequence were: flip angle 30°, TR 6ms, TE 1.4ms, bandwidth 31.25 kHz, slice thickness 1.2 mm, matrix 256×256. The sequence parameters were kept constant for the studies, whereas four selections were chosen: 1) with ZIP1024 and ZIP×4 techniques; 2) only with ZIP1024 technique; 3) only with ZIP×4 technique; 4) without ZIP technique. For image quality evaluation, MR maximum intensity projection (MIP) images were created. Signal-to-noise ratio (SNR) was measured on MIP images. Vessel edge was determined using full width at half maximum (FWHM) for lumen diameter calculation and results were compared with the actual lumen diameter. The distinctness of the vessel edge and the artifacts on the phantoms were compared for all sequences. Three experienced radiologists made consensus evaluation. The FWHM results of lumen measurements for all the sequences with ZIP techniques were more accurate than that of the sequence without ZIP technique in all phantoms, no matter what the size of the artery. The vessel edge with ZIP1024 technique was more distinct. However, the highest average SNR was obtained with the sequence without ZIP technique. The segmental stenosis artifacts on small artery of phantoms were only efficiently suppressed with the ZIP×4 technique. ZIP technique is excellent for CE-MRA to obtain high quality MR angiography. It not only can improve the spatial resolution and the distinctness of the vessel edge on CE-MRA, but can also efficiently suppress segmental stenosis artifact on small arteries of phantoms.

Primary Malignant Fibrous Histiocytoma (MFH) of skull is a rare tumour with malignant features similar to MFH located elsewhere. Primary MFH of bone may metastasize to soft tissues or other bones. We report a case of a metachronous MFH involving the skull.

With rising incidences of immunosuppression including HIV infection and various other factors, a resurgence of tuberculosis has been observed. We herewith describe two cases of posterior fossa tuberculomas with presentation mimicking mass lesions. Tuberculomas in the brain are not uncommon in the developing countries. Although they can mimic neoplastic lesions, the early diagnosis of tuberculous lesion with MRI and MR spectroscopy results in prompt institution of antituberculous therapy. Hypointensity in T2-weighted sequence with ring enhancement and the presence of a prominent lipid-lactate peak on MR spectroscopy is highly suggestive of the tuberculous nature of the lesion.

Fluid-attenuated inversion recovery (FLAIR) imaging with contrast enhancement is highly sensitive for detecting subarachnoid space disease. We hypothesized that contrast-enhanced FLAIR imaging with magnetization transfer would offer superior sensitivity to contrast-enhanced T1-weighted MR imaging with magnetization transfer in detecting TB meningitis. Forty-four patients referred for suspected TB meningitis underwent MR imaging studies. The patients had either proven TB meningitis or negative TB meningitis. The MR imaging examinations included both contrast-enhanced FLAIR and T1-weighted MR images with magnetization transfers that were independently reviewed by two neuroradiologists. Each of the sequences was reviewed individually and separately and was assigned a score of positive or negative for TB meningitis. Of the 21 studies of patients with proven TB meningitis, nine were positive based on contrast-enhanced FLAIR images with magnetization transfer, and 13 were positive based on contrast-enhanced T1-weighted MR images with magnetization transfer. Of the 23 studies of patients without TB meningitis, 19 were negative based on contrast-enhanced FLAIR images, and 20 were negative based on contrast-enhanced T1-weighted MR images with magnetization transfer. The sensitivity and specificity for contrast-enhanced FLAIR images for detecting TB meningitis were 43% (nine of 21) and 82% (19 of 23), respectively. The sensitivity and specificity of contrast-enhanced T1-weighted MR images with magnetization transfer for detecting TB meningitis were 62% (13 of 21) and 87% (20 of 23), respectively. Contrast-enhanced FLAIR imaging with magnetization transfer is less sensitive than contrast-enhanced T1-weighted MR sequences with magnetization transfer in detecting TB meningitis.

We present the MRI findings of delayed brain damage in a patient who underwent radiotherapy after resection of an oligo-astrocytoma. The lesions appeared years later within brain tissue that was included in radiation fields. High-field 3 Tesla MR investigation gave us the possibility to appreciate the different aspects of the vasculopathy induced by irradiation. A literature review allowed us to hypothesize the correlations between imaging and pathological findings.

We report two patients with persistent falcine vein associated with atretic parietal cephaloceles. Two children, aged two and eight months, were admitted to our department for MRI examination of the brain because of palpable parietal subscalp lesions. MRI study of the brain and MR-venography revealed a falcine sinus joining the superior sagittal sinus in a vertical position. The straight sinus was absent in its normal position. The parietal subscalp lesions were cyst-like formations under the skin associated with a small calvarial defect. The lesions were assumed to be atretic cephaloceles.

We describe the MR features which appeared after resection of a medulloblastoma in the posterior fossa in a boy who developed postoperative cerebellar mutism. The anatomical and physiopathological factors responsible for this disorder are discussed.

Leukoaraiosis (LA) is the widely accepted definition for the changes in the white matter of the brain frequently detected in the elderly by neuroimaging techniques. LA has a vascular pathogenesis and is a definite contributory factor for stroke, cognitive decline and dementia. Theoretically, though not yet in practice, if these lesions are detected at an early stage treatment can be instituted promptly, thereby preventing a catastrophic event later. Here we concisely review the relevant literature and stress the imaging of LA and its clinical significance.

The purpose of this study was to evaluate the median nerve sonographically and estimate the prevalence of carpal tunnel syndrome (CTS) in computer mouse users. Forty-nine right wrists of 49 employees who had used a computer mouse were included in the study. Thirty-three right wrists of 33 non-mouse user employees were studied as a control group. Both the mouse user and non-mouse user employees underwent sonography and electromyography (EMG). Axial sonograms of the median nerve were obtained proximally, in the middle and distally in the carpal tunnel. At each level, flattening ratio and the cross-sectional area of the median nerve were calculated. We found no significant difference in any parameters between mouse users and control group (p>0.05). However, when we compared mouse users according to the presence of pain, there was a significant increase in the cross-sectional area of the median nerve proximally in the mouse users having pain (p<0.05). Of all mouse users, eight (16.3%) were diagnosed as sensory CTS, four (8.2%) as motor CTS by EMG. We also found that four (50%) CTS patients had a proximal cross-sectional area of median nerve exceeding 10 mm² and five (62.5%) had a distal flattening ratio over three. Prolonged use of a mouse may pose an occupational risk for employees. Sonography can serve as an initial step in symptomatic patients for diagnosis of CTS.

Prolactin-secreting pituitary adenomas are the most common type of functional pituitary tumor. Bromocriptine therapy is an effective alternative to surgery in this group of patients. We report a case of prolactinoma where the patient was put on bromocriptine therapy and after 15 months of follow-up the tumor almost regressed giving an empty sella appearance.

The last effect of any thrombosis is recanalization. The aim of this study was to investigate the possibility of thrombosed cerebral venous vessels recanalization and the determination of optimal control methods after thrombolytic therapy. A group of 106 patients with adiagnosis of cerebral venous thrombosis after MRI, MR-angiography, ultrasound duplex scanning and CT-angiography underwent dynamic control examinations after thrombolytic therapy. MR-angiography and ultrasound duplex scanning appeared to be satisfactory and effective control methods to disclose thrombosed cerebral venous vessel recanalization. In our study venous vessels were recanalized in 15 cases (14%). The majority of cases of recanalization were revealed in the acute period of thrombosis.

The incidence of primary intracranial mixed germ-cell tumor varies geographically. Preoperative diagnosis is of great importance in treatment planning. We describe the clinical and MRI findings of a case of mixed germ-cell tumors in the suprasellar region with emphasis on the imaging characteristics suggesting the histological diagnosis.

Magnetic resonance brain scan in a 54-year-old man with ingravescent headache disclosed an expansive intraventricular non infiltrating process, hypointense in T1 and hyperintense in T2, without signal intensification after the injection of a paramagnetic contrast agent. The lesion was studied with diffusion and perfusion sequences. The Apparent Diffusion Coefficient and the Signal/Time Relative Intensity curves after perfusion study were analyzed. Diffusion images confirmed the solid nature of the lesion, while perfusion images displayed the vascular proliferation within the lesion. Diffusion and perfusion sequences were helpful in suggesting the neuroradiological diagnosis of subependymoma, subsequently confirmed by pathologic testing following the neurosurgical tumour resection.

Transradial angiography is a useful tool for diagnostic and interventional neuroangiographic procedures. It is routinely used for coronary angiography but there are few reports on the technique in neuroradiolocgical literature. Between April 2004 and February 2005 we enrolled 67 patients for transradial selective cerebral catheterization. We performed 56 diagnostic procedures, four interventional and seven failed accesses. Sheaths were used in all cases ranging in size from 4F to 6F. Standard shape angled Berenstein and Simmons (I, II) 4F catheters were used for three- and four-vessel diagnostic arteriography and 40° 5F and 6F guide catheters for interventional procedures (two external carotid, one vertebral embolization and one left cervical ICA stenting). Periprocedural complications included failure to access the radial/brachial artery (five patients), and transient radial artery spasm with pain (two patients). There were no major complications and/or deficits related to cannulation of the radial artery. Compared with transfemoral and transbrachial approaches, transradial access is a less invasive and safer technique for neuroangiography. Anticoagulant or antiplatelet therapy need not be discontinued for this method. All major vessels can be accessed for diagnostic studies and interventions in the vertebral system and in selected conditions of carotid anatomy are facilitated.

The association of persistent trigeminal artery (PTA) with intracranial vertebral artery fenestration is very rare. The commonest associations of PTA are with intracranial aneurysms, arteriovenous malformations, absence of internal carotid artery and vertebral arteries. We describe a case of persistent trigeminal artery associated with intracranial vertebral artery fenestration in a patient with right-sided type 1 carotid-cavernous fistula. To our knowledge, this is the first report of such an association.