Nilgün Yünten

Cerebral cortical and deep venous thrombosis without sinus thrombosis: clinical MRI correlates

Background –  Cortical and/or deep vein thrombosis (CDVT) without dural sinus involvement is uncommon and presents diagnostic difficulty for many reasons. Our aim is to determine the relationship between magnetic resonance imaging (MRI) findings and clinical findings in patients with CDVT.

Diffusion-weighted MR imaging of viral encephalitis

IntroductionThe aim of this study was to evaluate the role of diffusion-weighted imaging (DWI) in the diagnosis of viral encephalitis and its relationship with the stage of the illness.MethodsWe performed conventional magnetic resonance imaging (MRI) including T1-W, T2-W and fluid attenuated inversion recovery (FLAIR) sequences and DWI in 18 patients with viral encephalitis diagnosed on the basis of laboratory, clinical and radiologic findings. Based on the qualitative and quantitative comparison of the conventional MRI and DWI, the patients were divided into three groups. Apparent diffusion coefficient (ADC) values of the involved and contralateral normal brain tissues were computed and compared for each group. The degree of correlation between the time (TI) from the onset of neurologic symptoms to the MR examination and ADC values was determined.ResultsIn group I (n=11) DWI was superior to conventional MRI in detecting the encephalitic involved sites and in depicting the borders of the encephalitic lesions. In group II (n=4) DWI was similar to conventional MRI. In group III (n=3) conventional MRI was superior to DWI. Mean ADC values of affected versus contralateral normal brain tissues were 0.458±0.161×10−3 versus 0.86±0.08×10−3 in group I, 0.670±0.142×10−3 versus 0.93±0.07×10−3 in group II, and 1.413±0.211×10−3 versus 1.05±0.06×10−3 in group III. Patients in group I had significantly lower ADC values than those in group II, while patients in group III had the highest ADC values (P<0.05). The ADC values were significantly lower in the affected sites than in the unaffected sites of patients in groups I and II, but were significantly higher in the affected sites than in the unaffected sites of patients in group III (P<0.05). There was an excellent correlation between ADC values and duration of the disease (r=0.874, P=0.01).ConclusionDWI is superior to other conventional diagnostic MR sequences in the detection of early viral encephalitic lesions and depiction of the lesion borders and, in combination with other sequences, DWI may contribute to the determination of the disease phase.

Spectrum of the Posterior Inferior Cerebellar Artery Territory Infarcts

Background and Purpose: The clinical, etiological and stroke mechanisms are defined well before but the detailed clinical and etiologic mechanisms regarding to all clinical spectrum of posterior inferior cerebellar artery (PICA) infarcts were not systematically studied by diffusion-weighted imaging (DWI). Methods: Seventy-four patients with PICA territory ischemic lesion proved by DWI with decreased apparent diffusion coefficient and FLAIR (fluid attenuation inversion recovery) included in our Registry, corresponding to 2% of 3,650 patients with ischemic stroke, were studied. The presence of steno-occlusive lesions in the posterior circulation were sought by magnetic resonance angiography, and reviewed with a three-dimensional rotating cineangiographic method. Results: We found six subgroups of PICA territory infarcts according clinico-topographical relationship: (1) 9 patients with lesion in the territory lateral branch of PICA; (2) 23 patients with an infarct in the territory of medial branch of PICA; (3) 9 patients with a lesion involving both medial and lateral branches of the PICA; (4) 9 patients with cortical infarcts at the boundary zones either between medial and lateral branches of the PICA or between PICA and m/l superior cerebellar artery (SCA); (5) 10 patients with a lesion at the deep boundary zones either between medial and lateral PICA, or between PICA and medial/lateral SCA; (6)14 patients with concomitant multiple lesions in the PICA and in other vertebrobasilar artery territories. The main cause of PICA infarcts was extracranial large-artery disease in 30 patients (41%) patients, cardioembolism and in situ branch disease in 15 patients (20%) each. Conclusions: Multiple PICA territory lesions on DWI were not uncommon and could be caused by multiple emboli originating from break-up of atherosclerotic plaque in the subclavian/innominate-vertebral arterial system. DWI findings of single or multiple small lesions could account for some cases with transient and subtle cerebellar symptoms which have been considered before as ‘vertebrobasilar insufficiency’ without morphologic lesion. Different clinical-DWI correlations allow us to determine better definition of the topographical and etiological spectrum of acute PICA territory lesions, which was previously defined by pathological and conventional MRI studies.

Intracerebral metastasis showing restricted diffusion: correlation with histopathologic findings.

OBJECTIVE We aimed to detect the frequency of restricted diffusion in intracerebral metastases and to find whether there is correlation between the primary tumor pathology and diffusion-weighted MR imaging (DWI) findings of these metastases. MATERIAL AND METHODS 87 patients with intracerebral metastases were examined with routine MR imaging and DWI. 11 hemorrhagic metastatic lesions were excluded. The routine MR imaging included three plans before and after contrast enhancement. The DWI was performed with spin-echo EPI sequence with three b values (0, 500 and 1000), and ADC maps were calculated. 76 patients with metastases were grouped according to primary tumor histology and the ratios of restricted diffusion were calculated according to these groups. ADCmin values were measured within the solid components of the tumors and the ratio of metastases with restricted diffusion to that which do not show restricted diffusion were calculated. Fishers exact and Mann-Whitney U tests were used for the statistical analysis. RESULTS Restricted diffusion was observed in a total of 15 metastatic lesions (19, 7%). Primary malignancy was lung carcinoma in 10 of these cases (66, 6%) (5 small cell carcinoma, 5 non-small cell carcinoma), and breast carcinoma in three cases (20%). Colon carcinoma and testicular teratocarcinoma were the other two primary tumors in which restricted diffusion in metastasis was detected. There was no statistical significant difference between the primary pathology groups which showed restricted diffusion (p>0.05). ADCmin values of solid components of the metastasis with restricted diffusion and other metastasis without restricted diffusion also showed no significant statistical difference (0.72+/-0.16x10(-3)mm(2)/s and 0.78+/-21x10(-3)mm(2)/s respectively) (p=0.325). CONCLUSION Detection of restricted diffusion on DWI in intracerebral metastasis is not rare, particularly if the primary tumor is lung or breast cancer. However we found that there is no correlation between the metastasis showing restricted diffusion and primary pathology. Prospective studies with larger groups and more information are necessary regarding the correlation between the primary tumor histopathology and the ADC values of metastasis with restricted diffusion.

Multiple intracranial aneurysms in polyarteritis nodosa: MRI and angiography

Abstract In polyarteritis nodosa involvement of the central nervous system is infrequent; small cerebral infarcts are the most common neuroradiological finding. We report a 10-year-old boy with polyarteritis nodosa and intracranial haemorrhage. MRI showed an intracerebral haemorrhage. Angiography revealed two peripheral aneurysms in the posterior cerebral circulation, previously reported on only two occasions, and multiple microaneurysms in the hepatic, renal, mesenteric and even the lumbar arteries.

Isolated pontine infarction due to rhinocerebral mucormycosis

Abstract We report a patient with rhinocerebral mucormycosis whose initial central nervous system involvement was isolated pontine infarction due to basilar arteritis caused by the fungus. The patient was diagnosed and followed by MRI and CT and basilar arteritis was demonstrated well on MRI studies. Involvement of the skull base was shown on CT in the later stage of the disease. The unusual initial presentation of the infection is discussed.

Adhesive arachnoiditis causing cauda equina syndrome in ankylosing spondylitis: CT and MRI demonstration of dural calcification and a dorsal dural diverticulum.

Abstract We present the radiological features of a 42-year-old man with long-standing inactive ankylosing spondylitis (AS), demonstrating that arachnoiditis is a cause of a cauda equina syndrome (CES) in this disease. CT showed a dorsal arachnoid diverticulum causing scalloped erosion of the laminae, and punctate and curvilinear dural calcification. MRI revealed adhesion and convergence of the cauda equina dorsally into the arachnoid pouch, causing the dural sac to appear empty canal. To the best of our knowledge, dural calcification on CT is a new finding in AS, which may be related to the CES. Our findings support the hypothesis that chronic adhesive arachnoiditis with subsequent loss of meningeal elasticity may be the main cause of CES in AS.

Chondrosarcoma causing cervical neural foramen widening

Abstract Various neoplastic, vascular, and developmental causes may lead to spinal neural foraminal widening, the most common causes of spinal dumbbell lesions being schwannomas and neurofibromas. Occasionally, some other slow-growing tumors may cause neural foraminal widening. We report an exceptional case of a low-grade spinal chondrosarcoma which apparently developed from a pre-existing osteochondroma in the neural arcus of C6. The lesion passed through the C5–C6 foramen, producing a dumbbell mass.

Hypoplastic lumbar pedicle in association with conjoined nerve root MRI demonstration.

We report a case of aberrant hypoplastic pedicle of the fourth lumbar vertebra and ipsilateral conjoined nerve root. Ipsilateral retroisthmic laminar defect, dysplastic lamina and transverse process, enlargement of neural foramen, hypoplasia of superior and inferior articular facet were present as associated with other neural arch anomalies. The extent of these anomalies was well demonstrated by MR imaging.

Report of diffusion‐weighted MRI in two cases with different cerebral hydatid disease

Purpose: To present MRI findings in two cases of cerebral hydatid disease with an emphasis on diffusion‐weighted imaging (DWI) findings of Echinococcus granulosus (EG) versus Echinococcus alveolaris (EA). Results: EG lesions were isointense with cerebrospinal fluid in all sequences including DWI. On DWI, EA lesions remained hypointense on b=1000 s/mm2 diffusion‐weighted images. Apparent diffusion coefficient (ADC) values of EG and EA lesions were completely different from each other, 2.88±0.24×10−3 s/mm2 and 1.33±0.15×10−3 s/mm2, respectively. Conclusion: The ADC values could not be used to discriminate from other differential diagnoses.