Neuroradiology 0028-3940

Demaerel, P.

doi: 10.1007/s00234-002-0783-1pmid: 12185541

Several genes have been found to influence the different cells involved in the processes of foliation and fissuration in the mouse and rat cerebellum. In the light of these new concepts and on the basis of the imaging findings in 42 patients, a classification is proposed for abnormalities of foliation and fissuration. On the basis of recent genetic and experimental evidence on mechanisms which control the origin of the cerebellum, it is suggested that abnormalities of foliation and fissuration form a single group, with a spectrum of severity. Some patients have only abnormal fissuration of the anterior lobe (type 1a) and others additional dysplasia of the anterior and part of the posterior lobe (type 1b). Extension of abnormalities into the hemispheres is often seen in the latter group. A second group has vermian and hemisphere abnormalities (type 2). In addition to the malformation of the anterior lobe of the vermis, three different hemispheric lesions can be seen in this group: cortical dysgenesis, hypertrophy of the cerebellar cortex, and malorientation of the folia. The mild abnormalities (type 1a) can be considered an incidental observation without clinical relevance. The moderate and severe cerebellar anomalies (type 1b and 2) are always associated with cerebellar symptoms and/or signs.

Hayashi, N.; Tsutsumi, Y.; Barkovich, A.

doi: 10.1007/s00234-002-0793-zpmid: 12185542

Although the diagnosis of polymicrogyria currently depends largely on non-invasive imaging, no large imaging-based studies of polymicrogyria have been reported. Previous anatomic studies of polymicrogyria have been based on autopsy studies and most of the cases in those series were associated with porencephaly or schizencephaly. This retrospective MRI analysis of a group of patients with polymicrogyria, without associated porencephaly or schizencephaly, was conducted to elucidate gross morphological findings of polymicrogyria in a clinical population. Seventy-one patients with polymicrogyria diagnosed by MRI were reviewed by two radiologists. The location of polymicrogyria, the associated white matter anomalies and other associated central nervous system anomalies were assessed. The polymicrogyria was unilateral in 30 (42%) patients, bilateral in 41 (58%) patients. The lobes involved in polymicrogyria were frontal 69%, parietal 63%, temporal 38%, and occipital 7%. The cortex in the Sylvian fissures was involved in 80%. The striate cortex, cingulate gyrus, hippocampus and the gyrus rectus were often spared. Diminished volume of white matter was noted in 48%, perivascular space dilatation in 27% and large cortical veins in 51%. Polymicrogyria develops in specific topological regions, the majority being centered around the Sylvian fissures, and a minority in the inferior and medial aspects of the cerebral hemispheres or the occipital lobes. Diminished volume of the white matter and dilated perivascular spaces deeply embedded close to the dysplastic cortex and abnormal cortical venous enlargement superficial to the dysplastic cortex may be useful adjuncts in making the diagnosis.

Yang, D.; Korogi, Y.; Sugahara, T.; Kitajima, M.; Shigematsu, Y.; Liang, L.; Ushio, Y.; Takahashi, M.

doi: 10.1007/s00234-002-0816-9pmid: 12185543

Developments in MRI have made it possible to use diffusion-weighted MRI, perfusion MRI and proton MR spectroscopy (MRS) to study lesions in the brain. We evaluated whether these techniques provide useful, complementary information for grading gliomas, in comparison with conventional MRI. We studied 17 patients with histologically verified gliomas, adding multivoxel proton MRS, echoplanar diffusion and perfusion MRI the a routine MRI examination. The maximum relative cerebral blood volume (CBV), minimum apparent diffusion coefficient (ADC) and metabolic peak area ratios in proton MRS were calculated in solid parts of tumours on the same slice from each imaging data set. The mean minimum ADC of the 13 high-grade gliomas (0.92±0.27×10–3 mm2/s) was lower than that of the four low-grade gliomas (1.28±0.15×10–3 mm2/s) (P<0.05). Means of maximum choline (Cho)/N-acetylaspartate (NAA), Cho/creatine (Cr), Cho/Cr in normal brain (Cr-n) and minimum NAA/Cr ratios were 5.90±2.62, 4.73±2.22, 2.66±0.68 and 0.40±0.06, respectively, in the high-grade gliomas, and 1.65±1.37, 1.84±1.20, 1.61±1.29 and 1.65±1.61, respectively, in the low-grade gliomas. Significant differences were found on spectroscopy between the high- and low-grade gliomas (P<0.05). Mean maximum relative CBV in the high-grade gliomas (6.10±3.98) was higher than in the low-grade gliomas (1.74±0.57) (P<0.05). Echoplanar diffusion, perfusion MRI and multivoxel proton MRS can offer diagnostic information, not available with conventional MRI, in the assessment of glioma grade.

Deblaere, K.; Backes, W.; Hofman, P.; Vandemaele, P.; Boon, P.; Vonck, K.; Boon, P.; Troost, J.; Vermeulen, J.; Wilmink, J.; Achten, E.; Aldenkamp, A.

doi: 10.1007/s00234-002-0800-4pmid:

Sundgren, P.; Reinstrup, P.; Romner, B.; Holtås, S.; Maly, P.

doi: 10.1007/s00234-002-0777-zpmid: 12185545

The aim of our retrospective study was to determine the extent to which diffusion- and perfusion- weighted MRI combined with conventional MRI could be helpful in the evaluation of intensive care unit (ICU) patients who have unknown or unclear cerebral pathology underlying a serious clinical condition. Twenty-one ICU patients with disparity between the findings on brain CT scan and their clinical status were studied. All patients underwent conventional MR and diffusion-weighted imaging and 14 also had MR perfusion studies. Abnormalities were present on diffusion-weighted imaging of 17 of the 21 patients and on perfusion-weighted studies of 7 of 14 patients. The MRI results changed the preliminary/working diagnosis in six patients. In eight other patients, MRI revealed additional pathology that had not been suspected clinically, and/or characterized more closely findings that had already been detected by CT or suspected clinically. MRI showed abnormalities in four of the five patients who had normal CT. MRI findings suggested a negative clinical outcome in all nine patients who subsequently died. MRI findings also suggested positive long-term outcome in five of nine patients who improved significantly as based on Glasgow and extended Glasgow outcome scales. In the three unconscious patients who had normal diffusion- and perfusion-weighted imaging the clinical outcome was good. This study suggests that MRI in seriously ill ICU patients with unclear cerebral pathology can provide information that changes, characterizes, or supports diagnoses and/or prognoses and therefore facilitates further management.

Lövblad, Karl-Olof; Schneider, Jacques; Bassetti, Claudio; El-Koussy, Marwan; Guzman, Raphael; Heid, Oliver; Remonda, Luca; Schroth, Gerhard

doi: 10.1007/s00234-002-0751-9pmid: 12185546

Our aim was to assess the value of a new fast contrast-enhanced MR venography (CE-MRV) sequence in the investigation of normal and diseased cerebral veins. Conventional time-of-flight (TOF) MRV is time consuming, with imaging for a single sequence taking many minutes. MRI was performed with a clinical 1.5-T scanner; conventional TOF MRV followed by CE-MRV was performed using a modified 3D first-pass MR angiography sequence. Ten control subjects without cerebral pathology were studied as well as ten patients with cerebral venous thrombosis for a total of 20 studies with both sequences. CE-MRV was able to provide a set of complete MRV images in a significantly shorter time than conventional MRV sequencing could. The field of view also provided greater coverage of the vessels of the head and neck. CE-MRV also provided more extensive small vein detail and provided a better demonstration of intraluminal defects, despite a slightly lower resolution. Both methods were equally suited for the demonstration of venous thrombosis and demonstrated all cases equally well; however, CE-MRV provided more detailed information by showing partially obstructed sinuses and by showing better the presence of cortical collateral venous drainage.

Longo, M.; Blandino, A.; Ascenti, G.; Ricciardi, G.; Granata, F.; Vinci, S.

doi: 10.1007/s00234-002-0781-3pmid: 12185547

We report quantification of vasospasm following subarachnoid haemorrhage (SAH) and the effect of a new antivasospastic free radical scavenger (AVS) in rats, using an angiographic technique developed in our laboratory. We acquired single-exposure angiograms with mammographic equipment, using a 0.1 mm diameter focal spot and single-emulsion mammographic films. Contrast medium was injected through a PE50 catheter in the common carotid artery, after the external carotid artery had been ligated to divert flow towards the internal carotid artery territory. Measurements of the M1 and A1 segments and of the middle third of the basilar artery were made by projecting the angiograms directly as slides and using the endovascular catheter as an internal reference. We tested the technique on 40 male albino Sprague-Dawley rats divided into four groups: sham-operated+saline, SAH+saline, sham-operated+AVS and SAH+AVS. We were able to measure the diameter of the principal intracranial arteries in all the animals. With our technique, which is cost-effective when compared to many of those reported recently, we could detect intracranial vasospasm in all untreated rats with SAH, and confirm antivasospastic effects of AVS.

Urbach, H.; Hartmann, A.; Pohl, C.; Omran, H.; Wilhelm, K.; Flacke, S.; Schild, H.; Klockgether, T.

doi: 10.1007/s00234-002-0762-6pmid: 12185548

Little is known about whether recanalization of carotid territory occlusions by local intra-arterial thrombolysis (LIT) depends on the type of the occluding thromboembolus. We retrospectively analysed the records of 62 patients with thromboembolic occlusions of the intracranial internal carotid artery (ICA) bifurcation or the middle cerebral artery who were undergoing LIT with urokinase within 6 h of symptom onset. We determined the influence of thromboembolus type (according to the TOAST criteria), thromboembolus location, leptomeningeal collaterals, time interval from onset of symptoms to onset of thrombolysis, and patient's age on recanalization. The thromboembolus type was atherosclerotic in six patients, cardioembolic in 29, of other determined etiology in four, and of undetermined etiology in 23 patients. Thirty-three (53%) thromboembolic occlusions were recanalized. The thromboembolus location but not the TOAST stroke type nor other parameters affected recanalization. In the TOAST group of patients with cardioembolic occlusions recanalization occurred significantly less frequently when transoesophageal echocardiography showed cardiac thrombus. The present study underlines the thromboembolus location as being the most important parameter affecting recanalization. The fact that thromboembolic occlusions originating from cardiac thrombi had a lower likelihood of being resolved by thrombolysis indicates the thromboembolus type as another parameter affecting recanalization.

Arat, Anil; Islak, Civan; Saatci, Isil; Kocer, Naci; Cekirge, Saruhan

doi: 10.1007/s00234-002-0747-5pmid: 12185549

Posterior cerebral artery aneurysms are amenable to deconstructive surgical treatment because of the rich collateral supply of the distal posterior cerebral artery. This report retrospectively analyses the outcome of endovascular parent artery occlusion for large or fusiform distal posterior cerebral artery aneurysms. Medical records and cerebral angiograms from two endovascular centres were analysed retrospectively. Eight patients with large or fusiform distal posterior cerebral artery (PCA) aneurysms were treated by endovascular occlusion of the segment of the PCA at the site of the aneurysm. Three of those were treated urgently after acute subarachnoid haemorrhage, the remainder had elective treatment. The clinical and angiographic outcomes in seven patients were assessed at 6 to 12 months. A single case of occipital infarction resulting in permanent homonymous hemianopia was the only permanent complication. Of the remaining patients, six made excellent recoveries and one was lost to follow-up. No recurrence or re-bleeding was noted. Endovascular parent artery occlusion may be an alternative to surgical parent artery occlusion in distal PCA aneurysms which are not convenient for selective endovascular treatment or surgical clipping.

Nakahara, Toshinori; Sakamoto, Shigeyuki; Hamasaki, Osamu; Sakoda, Katsuaki

doi: 10.1007/s00234-002-0794-ypmid: 12185550

We report on two patients with intracranial atherosclerosis of the carotid artery or vertebral artery treated with stent-assisted angioplasty. Both patients have severe intracranial atherosclerosis (>70%) with refractory symptoms despite optimal medical treatment. In both patients, a coronary balloon-expandable stent was successfully placed using a protective balloon technique without procedural complications. The patients were asymptomatic and neurologically intact at a mean clinical follow-up of 13 months. Follow-up angiograms did not show restenosis 3 or 4 months after procedure, respectively. Stent-assisted angioplasty for intracranial atherosclerosis in the elective patient has proven effective, with an acceptable low rate of morbidity and mortality.