Ischemic involvement of the primary motor cortex is a prognostic factor in acute stroke.

BACKGROUND: The location of the primary motor cortex can be detected in healthy adults using the findings of 'T2 hypointensity' and the 'double layer sign' on 3 T diffusion-weighted imaging. The aim of this study was to assess whether ischemic involvement of the primary motor cortex can be identified on 3 T diffusion-weighted imaging within six-hours after stroke onset and to evaluate whether this finding could predict clinical outcome three-months after ischemic stroke. METHODS: Sixty-five patients who had paralysis and ischemia of the anterior circulation underwent 3 T magnetic resonance imaging within six-hours of symptom onset. Follow-up MRI was obtained at 72 h. Anatomic localization and ischemic involvement of the primary motor cortex were evaluated on diffusion-weighted imaging by two investigators. Ischemic involvement on the primary motor cortex was classified into three grades. Ischemic lesion volumes were measured. We compared the favorable outcomes at three-months between subjects with and without ischemic involvement on the primary motor cortex using the NIHSS and modified Rankin Scale. RESULTS: Ischemic involvement on the primary motor cortex was identified in 52% of patients. Interrater agreement coefficients were 0·93 for the identification of ischemic involvement of primary motor cortex. As defined by scores on the modified Rankin Scale, among the patients with ischemic involvement of the primary motor cortex were worse than the patients without ischemic involvement of the primary motor cortex (P = 0·01). The mean ischemic lesion volume at baseline diffusion-weighted imaging was 38·7 ± 41·7 cm(3) and was 89·8 ± 93·6 cm(3) at follow-up T2-WI. Ischemic involvement on the primary motor cortex (odds ratio: 14·7) was a determinant for worse outcome. CONCLUSIONS: 3T diffusion-weighted imaging can identify ischemic involvement on the primary motor cortex and may provide useful information for predicting outcome during the hyperacute stage. Ischemic involvement on the primary motor cortex has a significant negative impact on recovery.

Magnetic resonance imaging evaluation of fetal maxillary sinuses.

BACKGROUND AND OBJECTIVE: The growth of maxillary sinus is closely connected to the development of facial structures. However, its definition and reference standards on fetal magnetic resonance imaging (MRI) have not been analyzed so far. In this study, the objectives were to define and evaluate the fetal maxillary sinus (fMS) formation with MRI. METHODS: We reviewed T2-weighted coronal MRI images of 75 fetuses. The MRI features, time of appearance, and boundaries of fMS were defined. Craniocaudal and transverse diameters of both maxillary sinuses and bone biparietal diameters were measured and statistically evaluated. RESULTS: In 150 fMS site analysis, 91 fMSs were identified. The fMSs were visualized as a hyperintense structures on T2-weighted image above the tooth bud. It first appeared at the 22nd gestational week, and in 4% (3/75) of fetuses, there was unilateral development. Mean craniocaudal length was 2.84 mm (1.1-4.8 mm), and mean transverse diameter was 2.67 mm (1.5-4.2 mm). CONCLUSIONS: Magnetic resonance imaging features of fMS that should be sought for the assessment of craniofacial anatomy are identified in this study. Fetal maxillary sinuses can be observed as hyperintense structures on T2-weighted MRI images starting from 22 weeks of gestation. The growth of fMS follows a predictable course throughout gestation; however, the dimensions are larger than the previously reported ex vivo series.

Identification of fetal precentral gyrus on diffusion weighted MRI.

To investigate the association of the diffusion-weighted MR imaging characteristics of fetal preCG and gestational age. Forty-four fetuses with normal brain MRI findings were included in the study. Gestational ages ranged from 18 to 36 weeks (mean 25.2 weeks). All exams were performed with a 1.5-T scanner using a body array coil during free maternal breathing without sedation. Precentral gyrus was defined as the hyperintense strip anterior to the central sulcus, on the superior section of axial brain images at the level of superior frontal cortex. The presence of preCG hyperintensity was noted as observed/subtle/not observed at different b values (500, 1000 s/mm(2)) and on apparent diffusion coefficient (ADC) maps and compared to the imaging characteristics of the superior frontal cortex. Precentral gyrus was first detected at 25 weeks as a hyperintense strip on DWI and hypointense strip on ADC maps. Display of preCG b 1000 s/mm(2) images were better than b 500 s/mm(2). Between 25 and 27 weeks, in 40% of fetuses preCG was observed on one hemisphere, and it was evident bilaterally in 60% of cases. Starting from the 28th week, preCG was observed on both hemispheres in 100% of cases. Diffusion weighted imaging helps better understanding of the evolution of fetal preCG. The hyperintense preCG strip starts to appear at 25 weeks, and when interpreting fetal DWI after 28 weeks this may be a sign to be sought for in all fetuses and an indicator for normal development.

Asymptomatic remote cerebellar hemorrhage: CT and MRI findings.

The aim of this study was to evaluate the computed tomography (CT) and magnetic resonance imaging findings (MRI) of asymptomatic remote cerebellar hemorrhage (RCH) at the preoperative, early postoperative, and postoperative period. A total of 983 consecutive adult patients who underwent supratentorial craniotomies were included in the study. The ethics committee approved the study. The patient's clinical records and radiological examinations were retrospectively analyzed. All patients had preoperative CT and MRI examinations, immediate postoperative CT, and postoperative MRI within 24 h. The patients with the radiological diagnosis of RCH were followed up to 5 years. Eight asymptomatic RCH cases were recruited. The prevalence of asymptomatic RCH was 0.8% in our series. RCH was unilateral in two patients and bilateral in six patients. The postoperative CT was positive in two cases. The hemorrhage presented on MRI as folial linear hypointensities in six cases. In three cases (including one mixed case), punctate hypointense spots were identified at the superior cerebellar folia. Diffuse hemorrhage in the cerebellar tonsil, subarachnoid hemorrhage, and hemorrhage in the cerebellar vermis and the ventricles were also seen. The MRI findings were stable up to 5 years. The prevalence of asymptomatic RCH is higher than previously reported. Immediate postoperative CT is usually unremarkable; however, MRI demonstrates various hemorrhagic patterns at the cerebellum other than classical "zebra sign". This condition is self-limiting and no further investigation or follow-up study is required. In the proper clinical setting, the awareness of different hemorrhagic patterns in patients with RCH would prevent unnecessary investigations.

Diffusion tensor imaging of Guillain-Mollaret triangle in patients with hypertrophic olivary degeneration.

The aim of the study is to analyze diffusion tensor imaging (DTI) characteristics of the Guillain-Mollaret triangle (GMT) in patients with hypertrophic olivary degeneration (HOD) and to investigate their correlation with previously reported histopathology. DTI was performed in 10 patients diagnosed with HOD. Fractional anisotropy, apparent diffusion coefficient, axial diffusivity, and radial diffusivity were measured in the inferior olivary nucleus (IO), the central tegmental tract, the red and the dentate nuclei, and the superior cerebellar peduncle of HOD patients and compared to age, sex, and side-matched 10 neurologically normal population. The prominent finding on DTI in affected IO was an increase in radial diffusivity compatible with demyelination. While conventional magnetic resonance imaging did not show any sign of involvement in the other components of GMT, DTI demonstrated signal changes in all anatomical components of the GMT. Main DTI findings in GMT of patients with HOD were an increase in radial diffusivity representing demyelination and an increase in axial diffusivity that is reflective of neuronal hypertrophy. DTI parameters can reflect the spatiotemporal evolution of transneuronal degeneration associated with HOD in a manner consistent with the known pathologic stages of HOD.

Identification of the primary motor cortex: value of T2 echo-planar imaging, diffusion-weighted imaging and quantitative apparent diffusion coefficient measurement at 3 T.

OBJECTIVES: To investigate the primary motor cortex (PMC) concerning T2 shortening on T2 echo-planar imaging (EPI-T2) and the double-layer sign on diffusion-weighted imaging (DWI), and also to measure its apparent diffusion coefficient (ADC). METHODS: 3-T MR DWI was performed in 134 adult volunteers and 64 patients. T2 shortening was graded as hypointense or isointense compared with the signal of the superior frontal cortex (SFC). The double-layer sign of the PMC was graded as present or absent. Both findings (T2 shortening and double-layer sign) were evaluated independently by two authors. ADC of the PMC and the SFC were calculated using manually selected ROIs. RESULTS: T2 shortening was found in 131 adults and 62 patients by author 1 and in 132 adults and 61 patients by author 2 (kappa = 0.96 and 0.91). The double-layer sign was found in 131 adults and 61 patients by author 1 and in 127 adults and 58 patients by author 2 (kappa = 0.94 and 0.91). ADC values of the PMC and the SFC were different for all subjects (p < 0.01). CONCLUSIONS: T2 shortening and/or the double-layer sign on 3-T MR can be used to locate the PMC. The difference in ADC values between PMC and SFC is a distinguishing feature.

Role of echo Doppler ultrasonography in the evaluation of postprandial hyperemia in cirrhotic patients.

AIM: To assess the role of echo-Doppler ultrasonography in postprandial hyperemia in cirrhotic patients by comparing the results with the hepatic vein catheterization technique. METHODS: Patients with cirrhosis, admitted to the portal hemodynamic laboratory were included into the study. After an overnight fast, echo-Doppler ultrasonography (basal and 30 min after a standard meal) and hemodynamic studies by hepatic vein catheterization (basal, 15 min and 30 min after a standard meal) were performed. Ensure Plus (Abbot Laboratories, North Chicago, IL) was used as the standard liquid meal. Correlation analysis of the echo-Doppler and hepatic vein catheterization measurements were done for the basal and postprandial periods. RESULTS: Eleven patients with cirrhosis (5 Child A, 4 Child B, 2 Child C) were enrolled into the study. After the standard meal, 8 of the 11 patients showed postprandial hyperemia with increase in portal blood flow, portal blood velocity and hepatic venous pressure gradient. Hepatic venous pressure gradient in the postprandial period correlated positively with postprandial portal blood velocity (r = 0.8, P < 0.05) and correlated inversely with postprandial superior mesenteric artery pulsatility index (r = -1, P < 0.01). CONCLUSION: Postprandial hyperemia can be efficiently measured by echo-Doppler ultrasonography and the results are comparable to those obtained with the hemodynamic studies.

Dynamic contrast-enhanced MRI in the differentiation of posttreatment fibrosis from recurrent carcinoma of the head and neck.

OBJECTIVE: The aim of this study was to investigate the value of dynamic contrast-enhanced magnetic resonance imaging (MRI) in the differentiation of posttreatment fibrosis from recurrent carcinoma, by comparing the dynamic contrast-enhancement characteristics of the lesions. MATERIALS AND METHODS: Twenty-six patients with previously treated carcinoma of the head and neck are studied by conventional and dynamic contrast-enhanced MRI at least 6 months after treatment by radiotherapy and/or surgery. Patients are divided into tumor-positive or -negative groups according to the radiological and clinical follow-up and biopsy. Lesion enhancement ratios at each dynamic sequence are calculated. RESULTS: The tumor-positive group consisted of 11 patients, while the tumor-negative group included 15 patients. Between the two groups, lesion enhancement ratios are found to be significantly different (P<.05). CONCLUSION: Dynamic contrast-enhanced MRI may be a valuable modality in the differentiation of recurrent tumor from posttreatment fibrotic changes of the head and neck.

An anencephalic monocephalus diprosopus "headed twin": postmortem and CT findings with emphasis on the cranial bones.

Monocephalus diprosopus is a form of conjoined twinning characterized by a single body, one unusual head and two faces or a spectrum of duplication of the craniofacial structures. Such cases have been mainly described according to postmortem pathologic examination. This presented case is a 26-week-stillborn female fetus, with unusual facial appearance with four eyes, two mouths, two noses, two ears and a defective cranial vault. To our knowledge, a detailed computerized tomography (CT) examination of the aberrant facial and cranial bones of such a case has not been reported to date. In this reported case, we present an anencephalic monocephalus diprosopus "headed twin", and describe the CT findings with emphasis on the cranial bones.

[Intraarterial thrombolysis in the treatment of acute ischemic stroke: Technical and clinical results]. / Akut iskemik inme tedavisinde lokal intraarteryel tromboliz: teknik ve klinik sonuçlar.

PURPOSE: To evaluate the safety and recanalization efficacy of local IA rt-PA delivery in patients with acute ischemic stroke. MATERIALS AND METHODS: Fifteen patients with acute ischemic stroke were treated; of these, 10 were carotid artery stroke, 5 were vertebrobasilar territory stroke cases. The neurological status of the patients were graded according to the Glascow Coma Scale and National Institutes of Heart Stroke Scale. All patients underwent a CT examination on admission. In addition, 4 patients had diffusion-weighted and one patient had a perfusion MR examination. Patients of carotid territory stroke were treated within 6 hours from the stroke onset. There was no time limitation for the basilar artery territory. The Rankin Scale (RS) was used as outcome measures. RESULTS: Two of the 10 patients with carotid artery stroke had carotid territory occlusions, 8 had middle cerebral artery main trunk occlusions. Four patients had symptomatic hemorrhage; of these, 3 died within 24 hours. At the third month 4 patients had a good outcome. Of 5 patients with basilar artery stroke, 4 had basilar artery occlusions. In one patient, the basilar artery was open but the flow of the contrast material was very slow. Two patients with unsuccessful recanalization due to underlying high grade atherosclerotic stenosis and one patient with successful recanalization died. At the third month, the other patient with succesful recanalization had a poor outcome (RS 4). The patient with slow basilar artery flow developed from RS 5 to RS 1 and was discharged without any neurological deficit. CONCLUSION: In acute ischemic stroke, local IA thrombolysis is a safe and feasible treatment when the right patient is selected. Hemorrhage does not exceed that which occurs in the natural history of the disease and with other treatment methods.

Venous variations in the region of the third ventricle: the role of MR venography.

In this study, we examined the anatomical variations of the subependymal veins in the region of the foramen of Monro and the third ventricle by MR time of flight (TOF) venography. Fifty healthy subjects, ten patients with third-ventricle tumors, and four patients with lateral-ventricle tumors were included in the study. The courses of the anterior septal vein (ASV), thalamostriate vein (TSV), and internal cerebral vein (ICV) were studied. The proximity of the venous angle, the false venous angle, and the ASV-ICV junction to the posterior margin of the foramen of Monro was measured. In 69 (53.9%) sides, the ASV-ICV junction was located at the venous angle and at the posterior margin of the foramen of Monro. In 59 (46.1%) sides, the ASV-ICV junction was located beyond the foramen of Monro. Our study shows the high incidence of posteriorly located ASV-ICV junctions, which can be crucial in the planning of a better surgical approach. We strongly recommend that MR venography, which is a short radiological examination, be used before one operates on third-ventricle and lateral-ventricle tumors.

Early-postoperative magnetic resonance imaging in glial tumors: prediction of tumor regrowth and recurrence.

OBJECTIVE: This study investigated the value of early-postoperative magnetic resonance (EPMR) imaging in the detection of residual glial tumor and investigated the role of EPMR for the prediction of tumor regrowth and recurrence. METHODS AND MATERIALS: We retrospectively analyzed pre- and post-operative magnetic resonance imaging results from 50 adult patients who underwent surgical treatment for supratentorial glial tumor. There were glioblastoma multiforme in 25 patients, astrocytoma (grades II and III) in 11 patients, oligodendroglioma (grades II and III) in 9 patients, and oligoastrocytoma (grades II and III) in 5 patients. EPMR imaging was performed within 24 h after surgery. EPMR findings were compared with the neurosurgeon's intraoperative estimation of gross tumor removal. Patterns of contrast enhancement at the resection site, in residual and developing tumor tissue and blood at the resection site were evaluated on EPMR and in follow-up studies. 'Residual tumor' was defined as contrast enhancing mass at the operative site on EPMR. 'Regrowth' was defined as contrast enhancing mass detected on follow-up in the same location as the primary tumor. 'Recurrence' was defined as appearance of a mass lesion in the brain parenchyma distant from the resection bed during follow-up. RESULTS: Nineteen patients showed no evidence of residual tumor, regrowth, or recurrence on EPMR or any of the later follow-up radiological examinations. EPMR identified 20 cases of residual tumor. Follow-up showed tumor regrowth in 10 patients, and tumor recurrence in 1 case. EPMR showed contrast enhancement of the resection bed in 45 of the 50 patients. Four of the 20 residual tumors showed a thick linear enhancement pattern, and the other 16 cases exhibited thick linear-nodular enhancement. No thin linear enhancement was observed in the residual tumor group. Nine of the 10-regrowth tumors showed a thick linear-nodular enhancement pattern, and one exhibited thin linear enhancement in EPMR. For predicting regrowth tumor EPMR sensitivity was 91%, specificity was 100%, positive predictive value 1; negative predictive value was 0.9375. CONCLUSION: EPMR, depending on the surgical site enhancement pattern, is a valuable means of demonstrating residual tumors, and can be used to predict possible regrowth after surgery.