Cem Calli

Intracranial calcifications on CT.

Computed tomography (CT) is very sensitive for detection and localization of intracranial calcifications. We reviewed in this pictorial essay the diseases associated with intracranial calcifications and emphasized the utility of CT for the differential diagnosis.

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.

The mechanism of ischemic stroke in patients with dolichoectatic basilar artery

Basilar artery dolichoectesia (BD) may cause brainstem ischemia by multiple mechanisms, including thrombosis, embolism, occlusion of deep penetrating arteries. The objective of this study was to determine and characterize clinical, imaging findings and hemodynamic mechanisms in patients with cerebrovascular event associated with BD and compare these data with those for patients with BD who did not have stroke. We studied 29 consecutive stroke, two transient ischemic attack (TIA) patients with BD who have been admitted to our stroke unit. We sought the diameter of ectasia, height of the bifurcation, lateral displacement, shape deformities, and blood flow velocity of the basilar artery (BA) by transcranial Doppler. Imaging and hemodynamic findings were compared with those found in a group of 18 patients without stroke or TIA. The main infarct localization was pons, eight (28%) with restricted single lesion, 10 (32%) with multiple lesions involving thalamus, midbrain, posterior cerebral artery (PCA) territory. Patients with BD were more probably to have had stroke fitting a clinical and imaging patterns of multiple infarcts than those with restricted infarct in territories supplied by branches of the BA (60% vs. 40%). Hypertension and atherosclerotic changes of the posterior circulation were more frequent in patients with stroke than those without (P = 0.004 and P = 0.028, respectively), whilst the incidence of other vascular risk factors were not significantly different in two groups. Patients with stroke/TIA had more often low blood flow velocity but not significant in the BA when compared with those for BD patients without cerebrovascular event (71% vs. 39%; P = 0.1). Reduced blood flow velocity in the BA was correlated significantly with distal lesions involving thalamus, midbrain and PCA territory rather than those located in the territory supplied by branches of the BA (P = 0.02). In conclusion, it seems probably that BD may cause vertebrobasilar system ischemia by multiple mechanisms, especially reduced blood flow in the BA and atheromatous changes in the vertebrobasilar system may precipitate thromboembolic stroke.

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.

Dysarthria due to Supratentorial and Infratentorial Ischemic Stroke: A Diffusion-Weighted Imaging Study

Background and Purpose: Dysarthria characterized by slurring with imprecise articulation without evidence of aphasia is a frequent symptom in the acute phase of cerebral ischemia, although there is little knowledge on its anatomic specificity and spectrum of associated clinical characteristics regarding diffusion-weighted imaging (DWI). Methods: An investigation of 101 consecutive patients with sudden-onset dysarthria due to a single or multiple lesions on DWI, corresponding to 8.7% of 1,160 patients with ischemic stroke, was made. The presence of lesions of the cranial arteries was sought by magnetic resonance angiography and reviewed with a three-dimensional rotating cineangiographic method. Results: Dysarthria was mostly associated with a supratentorial lesion (63%) and with a classic lacunar stroke syndrome in 45% of patients. Lacunar lesions on DWI were found in 69 (68%) patients, while only 45 of the patients (65%) with a lacunar infarct presented a classic lacunar syndrome with dysarthria. Pure dysarthria occurred in 15% of patients, dysarthria + pure motor hemiparesis in 14%, dysarthria + ataxic hemiparesis in 11%, dysarthria + clumsy hand syndrome in 7%, dysarthria + pure sensory stroke in 3%, dysarthria + central facial paresis in 8% and lingual paresis occurred in 2%. The lesions were due to small-artery disease in 41%, large-artery disease in 15%, cardioembolism in 10% and a mixed etiology in 3%. The cause of stroke was not identified in 17 patients. Lesions on DWI were found mainly in the corona radiata (n = 18), middle cerebral artery territory, including the motor cortex and/or insular cortex (n = 13), striatocaudate nuclei (n = 11), primary motor cortex (n = 10), internal capsule (n = 7), pons (n = 25), pontobulbar junction (n = 5) and the thalamomesencephalic junction (n = 4). Isolated cerebellar infarctions (n = 6) or associated brainstem lesions (n = 6) affected mostly the superior cerebellar artery or the posterior inferior cerebellar artery territory. Conclusion: Cortical involvement was more frequent in patients with pure dysarthria than those with dysarthria and additional neurological signs, while the frequency of pontine involvement was higher in patients with additional neurological signs than those with pure dysarthria. One third of the patients with dysarthria had multiple lesions on DWI, and the most common cause of stroke was small-artery disease. Pure dysarthria, dysarthria with lingual paresis, dysarthria with clumsy hand and dysarthria with facial paresis had predictive value for lacunar lesions.

The clinical spectrum of intracerebral hematoma, hemorrhagic infarct, non‐hemorrhagic infarct, and non‐lesional venous stroke in patients with cerebral sinus–venous thrombosis

Background and purpose:  The clinical spectrum of different neuroradiological features of cerebral sinus–venous thrombosis (CSVT) varies considerably. We sought the relationship between different neuroradiological aspects and clinical presentations in these patients.

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.

Brucellar spondylodiscitis: magnetic resonance imaging features with conventional sequences and diffusion-weighted imaging

PurposeIn this retrospective study, we evaluated the contribution and role of diffusion-weighted imaging (DWI) in differentiating acute and chronic forms of brucellar spondylodiscitis. We also describe the characteristics and some indistinguishable features of brucellar spondylodiscitis on magnetic resonance imaging (MRI) to emphasise the importance and limitations of MRI.Materials and methodsMRI examinations of 25 patients with brucellar spondylodiscitis were retrospectively reviewed and analysed by two experienced radiologists. Signal and morphological changes were assessed. The imaging characteristics of acute and chronic forms of spondylodiscitis were compared. Both discriminative imaging findings of brucellar spondylodiscitis and some uncommon findings were interpreted.ResultsOf 25 patients with spinal brucellosis, eight had thoracic, ten had lumbar, five had both thoracic and lumbar and two had both lumbar and sacral vertebral involvement. We detected posterior longitudinal ligament elevation in 11 patients, epidural abscess formation in 11 and paravertebral abscess formation in nine. Ten patients had cord compression and eight had root compression. Three patients had facet-joint involvement, and one had erector spinae muscle involvement. Eight patients (32%) were in the acute stage, six (24%) in the subacute stage and 11 (44%) in the chronic stage. Vertebral bodies, vertebral end plates and intervertebral disc spaces were hypointense and hyperintense in the acute stage, whereas they were hypointense and heterogeneous in the subacute and chronic stages on T1- and T2-weighted images, respectively. In the acute stage on the DWI series, vertebral bodies, end plates and discs were all hyperintense but hypointense in the chronic stage.ConclusionsAlthough conventional MRI has several advantages over other imaging modalities and is very useful in the differential diagnosis between brucellar spondylodiscitis and other spinal pathologies, it has some difficulties in discriminating acute and chronic forms of spondylodiscitis. DWI is a sensitive, fast sequence that has the potential for differentiating acute and chronic forms of spondylodiscitis, which makes it crucial in spinal imaging.AbstractObiettivoIn questo studio retrospettivo abbiamo valutato il contributo e il ruolo della sequenza pesata in diffusione nella diagnosi differenziale tra forme acute e croniche di spondilodiscite brucellare. Abbiamo inoltre descritto le caratteristiche e alcuni aspetti patognomonici della spondilodiscite brucellare nell’imaging di Risonanza Magnetica (RM) per sottolineare l’importanza e i limiti della RM.Materiali e MetodiLe indagini RM di 25 Pazienti con spondilodiscite brucellare sono state rivalutate e analizzate retrospettivamente da due radiologi esperti. Sono state valutate le alterazioni morfologiche e del segnale. Sono state inoltre messe a confronto le caratteristiche di immagine delle forme acute e croniche. Infine sono stati interpretati sia alcuni aspetti di immagine discriminativi della spondilodiscite brucellare che alcuni reperti rari.RisultatiDei 25 Pazienti con brucellosi spinale, 8 presentavano un interessamento toracico, 10 lombare, 5 sia toracico che lombare e 2 sia lombare che sacrale. Abbiano rilevato sollevamento del legamento longitudinale posteriore in 11 Pazienti, formazione di ascessi epidurali in 11 e presenza di ascessi paravertebrali in 9. Dieci Pazienti avevano compressione del midollo e 8 compressione radicolare. Tre Pazienti presentavano coinvolgimento delle faccette articolari e uno del muscolo erettore spinale. Otto Pazienti (32%) erano in fase acuta, 6 (24%) in fase subacuta e 11 (44%) in fase cronica. I corpi vertebrali, i piatti vertebrali e i dischi intervertebrali erano ipointensi e iperintensi nello stadio acuto, mentre erano ipointensi e eterogenei negli stadi subacuto e cronico, rispettivamente nelle sequenze T1- e T2 dipendenti. In fase acuta, nella sequenza pesata in diffusione, i corpi vertebrali, i piatti e i dischi erano tutti iperintensi mentre erano ipointensi in fase cronica.ConclusioniNonostante la RM convenzionale abbia parecchi vantaggi rispetto ad altre metodiche di immagine e sia molto utile nella diagnosi differenziale tra la spondilodiscite brucellare e altre patologie spinali, tale metodica presenta delle difficoltànel differenziare le forme acute e croniche della spondilodiscite. L’imaging pesato in diffusione è una sequenza sensibile e veloce che possiede il potenziale per differenziare le forme acute e croniche di spondilodiscite rendendola pertanto fondamentale nella diagnostica per immagini spinale.