Differential Lesion Patterns on T2WI and FLAIR Sequences in Cryptogenic Stroke Patients With Patent Foramen Ovale.

OBJECTIVES: The purpose of this study was to determine lesion patterns and stroke mechanisms in cryptogenic ischemic stroke patients with patent foramen ovale (PFO) on T2-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequences combined. PARTICIPANTS AND METHODS: Twenty-nine patients with cryptogenic ischemic stroke and an isolated PFO (CS-PFO+ group) compared with 51 cryptogenic stroke patients without PFO (CS-PFO- group) were evaluated and the characteristics of their lesion patterns on T2-weighted and fluid-attenuated inversion recovery sequences combined were investigated. We compared the number, the size, and the distribution of ischemic lesions on magnetic resonance imaging between the 2 groups. RESULTS: Twenty-four of 29 patients had a total of 271 small ischemic lesions (diameter<1 cm) in the CS-PFO+ group against 24 of 51 patients with 156 small ischemic lesions in the CS-PFO- group, respectively; 11.29±8.14 and 6.36±4.33 ischemic lesions per person (P=0.015). Multiple small ischemic lesions occurred more frequently in the CS-PFO+ group (20/29, 69%) than in the CS-PFO- group (16/51, 31%, P=0.001). Subcortical frontal and parietal infarct lesions were more frequent in the CS-PFO+ group (19/29, 66%) than in the CS-PFO- group (18/51, 35%, P=0.009). CONCLUSIONS: Multiple small ischemic lesions and subcortical frontal and parietal infarct lesions were significantly associated with cryptogenic stroke patients with PFO, which suggested that paradoxical embolism is the pathogenic mechanism in cryptogenic stroke patients with PFO.

Susceptibility-Weighted Imaging of the Anatomic Variation of Thalamostriate Vein and Its Tributaries.

BACKGROUND AND PURPOSE: Thalamostriate vein (TSV) is an important tributary of the internal cerebral vein, which mainly drains the basal ganglia and deep medulla. The purpose of this study was to explore the anatomic variation and quality of TSV and its smaller tributaries using susceptibility-weighted imaging (SWI). METHODS: We acquired SWI images in 40 volunteers on a 3.0T MR system using an 8-channel high-resolution phased array coil. The frequencies of the TSV and its tributaries were evaluated. We classified TSV into types I (forming a venous angle) and II (forming a false venous angle). We classified anterior caudate vein (ACV)into types 1 (1 trunk) and 2 (2 trunks) as well as into types A (joiningTSV), B (joining anterior septal vein), and C (joining the angle of both veins). RESULTS: The TSV drains the areas of caudate nucleus, internal capsule,lentiform nucleus, external capsule, claustrum, extreme capsule and the white matter of the frontoparietal lobes,except thalamus. The frequencies of the TSV, ACV and transverse caudate vein (ACV) were 92.5%, 87.5% and 63.8%, respectively. We found TSV types I and II in 79.7%, and 20.3% with significantly different constitution ratios (P< 0.05). The most common types of ACV were type 1 (90.0%) and type A (64.3%). CONCLUSION: The complex three-dimensional (3D) venous architecture of TSV and its small tributaries manifests great variation, with significant and practical implications for neurosurgery.

Susceptibility-weighted imaging of the venous networks around the brain stem.

INTRODUCTION: The venous network of the brainstem is complex and significant. Susceptibility-weighted imaging (SWI) is a practical technique which is sensitive to veins, especially tiny veins. Our purpose of this study was to evaluate the visualization of the venous network of brainstem by using SWI at 3.0 T. METHODS: The occurrence rate of each superficial veins of brainstem was evaluated by using SWI on a 3 T MR imaging system in 60 volunteers. The diameter of the lateral mesencephalic vein and peduncular vein were measured by SWI using the reconstructed mIP images in the sagittal view. And the outflow of the veins of brainstem were studied and described according to the reconstructed images. RESULTS: The median anterior pontomesencephalic vein, median anterior medullary vein, peduncular vein, right vein of the pontomesencephalic sulcus, and right lateral anterior pontomesencephalic vein were detected in all the subjects (100%). The outer diameter of peduncular vein was 1.38 ± 0.26 mm (range 0.8-1.8 mm). The lateral mesencephalic vein was found in 75% of the subjects and the mean outer diameter was 0.81 ± 0.2 mm (range 0.5-1.2 mm). The inner veins of mesencephalon were found by using SWI. CONCLUSION: The venous networks around the brain stem can be visualized by SWI clearly. This result can not only provide data for anatomical study, but also may be available for the surgical planning in the infratentorial region.

Whole-brain 320-detector row dynamic volume CT perfusion detected crossed cerebellar diaschisis after spontaneous intracerebral hemorrhage.

INTRODUCTION: The purpose of this study was to evaluate the value of 320-detector row CT used to detect crossed cerebellar diaschisis (CCD) in patients with unilateral supratentorial spontaneous intracerebral hemorrhage (SICH). METHODS: We investigated 62 of 156 patients with unilateral supratentorial SICH using 320-detector row CT scanning. Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), mean transit time (rMTT), and time to peak (rTTP) levels were measured in different regions of interest (ROIs) that were manually outlined on computed tomography perfusion (CTP) for the cerebrum, including normal-appearing brain tissue that surrounded the perilesional low-density area (NA) and the perihematomal low-density area (PA) in all patients and the cerebellum (ipsilateral and contralateral) in CCD-positive patients. RESULTS: Of 62 cases, a total of 14 met the criteria for CCD due to cerebellar perfusion asymmetry on CTP maps. In the quantitative analysis, significant differences were found in the perfusion parameters between the contralateral and ipsilateral cerebellum in CCD-positive cases. No significant differences were found between the CCD-positive group and the CCD-negative group according to the hematoma volume, NIHSS scores, and cerebral perfusion abnormality (each P > 0.05). The correlation analysis of the degree of NA, PA perfusion abnormality, and the degree of CCD severity showed negative and significant linear correlations (R, -0.66∼-0.56; P < 0.05). CONCLUSION: 320-detector row CT is a robust and practicable method for the comprehensive primary imaging work-up of CCD in unilateral supratentorial SICH patients.

Differential lesion patterns on T2-weighted magnetic resonance imaging and fluid-attenuated inversion recovery sequences in cryptogenic stroke patients with patent foramen ovale.

BACKGROUND: The present study aimed to determine lesion patterns and the stroke mechanisms in cryptogenic ischemic stroke patients with patent foramen ovale (PFO) on T2-weighted magnetic resonance imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequences combined. METHODS: In this retrospective study, 38 patients with cryptogenic stroke and an isolated PFO compared with 51 cryptogenic stroke patients without PFO were evaluated and their characteristics of lesion patterns on T2WI and FLAIR sequences combined were investigated. The number, distribution of small ischemic lesions, and the frequency of multiple small ischemic lesions were analyzed between the 2 groups. RESULTS: Thirty-two of 38 patients had a total of 341 small ischemic lesions in cryptogenic stroke patients with PFO versus 24 of 51 patients with 156 small ischemic lesions in patients without PFO, and, 8.97±7.91 and 3.19±4.82 ischemic lesions per person, respectively. Multiple small ischemic lesions occurred more frequently in cryptogenic stroke patients with PFO (25 of 38 patients, 66%) than in patients without PFO (16 of 51 patients, 31%; P=.001). Subcortical frontal and parietal small lesions were more frequent in cryptogenic stroke patients with PFO (28 of 38 patients, 74%) than in patients without PFO (18 of 51 patients, 35%; P<.0001). CONCLUSIONS: Multiple small ischemic lesions and subcortical frontal and parietal small lesions were significantly associated with cryptogenic stroke patients with PFO, suggesting that paradoxical embolism may be the mechanism of PFO-associated cryptogenic stroke patients.

[Study of intracerebral focus changes on CADASIL by using MR imaging].

OBJECTIVE: To investigate dynamic changes of intracerebral focus on cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). METHODS: Using the modified Scheltens scale, the magnetic resonance (MR) changes of lesion distribution, size and shape in 7 patients from a CADASIL family were retrospectively analyzed during 3 years observed. RESULTS: In 6 of 7 patients, the number and volume of lesion areas in the white matter were increased (parietal lobe, n = 6; temporal lobe, n = 5; frontal lobe, n = 3; occipital lobe, n = 2) and some areas even became confluent as a mass or chain. New lacunar infarcts (n = 1 - 5) appeared in 5 patients and the arcuate fiber were involved in 1 patients. Slight enlargement could be seen in lateral ventricle (n = 1) or lateral ventricle with third ventricle (n = 1). CONCLUSION: MR imaging can help us to reveal dynamic changes of brain lesions and prognosis in patients with CADASIL.

[Functional magnetic resonance imaging of whole brain related to motor preparation and execution].

OBJECTIVE: To investigate the roles the different functional activation areas in whole human brain related to movement play during motor preparation (CUE) and execution (GO). METHODS: Event-related functional MRI technique was used on 12 right-handed healthy subjects to record the brain activation in a manner of delayed sequential finger movement. Activation maps and time-signal intensity curves were generated. RESULTS: Bilateral anterior parts of supplementary motor area (Pre-SMA), bilateral posterior parietal cortex (PPC), and bilateral anterior premotor cortex (PMC) were strongly activated during the preparation period, while bilateral SMA proper, and contralateral primary motor cortex (M1) were strongly activated during the execution period, Cerebellar cortex was activated during both periods. The time-signal intensity curves based on single voxel indicated that above-mentioned brain areas were activated during both periods to different degrees; however, the characteristics of distribution in every area were different. CONCLUSION: The brain areas related to movement are activated differently during preparation period and execution period, areas close to M1 participate in the motor execution process mainly, and the areas away from M1 are concerned with motor preparation process chiefly.

Application of MRI in indirect temporomandibular joint injury without condylar fracture.

OBJECTIVE: To discuss the application of MRI in indirect temporomandibular joint injury without condylar fracture. METHODS: MRI examination on temporomandibular joint was conducted in 28 patients with indirect injury to temporomandibular joint without condylar fracture. The scanning sequence included T(1)WI, PDWI on oblique sagittal section at both open and closed mouth positions, and T(1)WI, T(2)WI on oblique coronal section. The MRI appearance was analyzed by 2 senior radiologists. RESULTS: Among the 56 temporomandibular joints of 28 patients, 35 joints exhibited pathological changes on MRI, in which there were 9 bone injuries, 21 articular disc dislocation, 24 intracapsular hematocele and hydrops. CONCLUSIONS: MRI can clearly reveal bone injury, articular disc dislocation as well as articular capsule abnormality in the indirect injury of temporomandibular joint without condylar fracture. It is highly advocated in clinical use.

[Study of paroxysmal kinesigenic dyskinesia with fMRI].

OBJECTIVE: To detect the differences in subcortical structures between patients with paroxysmal kinesigenic dyskinesia (PKD) and normal subjects during movement preparation and execution. METHODS: The PKD patients performed a movement task, in which a CUE signal (preparation) indicated the movement sequence prior to the appearance of an imperative GO signal (execution). Event-related functional magnetic resonance imaging (fMRI) and 3dDeconvolve program of AFNI were used to estimate the hemodynamic response function and to generate activation maps. RESULT: During movement preparation, the activated brain areas in PKD patients were less than those of normal subject, and there was no activation in basal ganglia in PKD patients. During execution, the activation was also less in PKD patients except in bilateral M1. CONCLUSION: During intermission, abnormalities of the brain still exist in PKD patients when during preparing or performing movement. The movement circuit in the brain displays an unusual state. The attack may be caused by reducing of inhibition in brain areas.

[Lateralized distribution of motor areas involved in voluntary movement].

OBJECTIVE: To investigate the brain functional laterality in motor areas during motor execution systematically. METHODS: Functional magnetic resonance imaging (fMRI) was employed combined with right hand sequential finger movement task to investigate brain activation pattern and laterality in 8 right-handed subjects. 3dDeconvolve program of AFNI was used to estimate the hemodynamic response function and to generate activation maps. Then the laterality index (LI) was calculated and tested statistically. RESULT: All motor areas including the areas which were previously considered to be engage in movement preparation only were activated in movement execution. In the activation map, it appeared left lateralization in cerebra and right lateralization in cerebella. After further statistical test, it was found that in primary motor area (M1), supplementary motor area (SMA) and posterior parietal cortex (PPC), there were left lateralization. While in premotor cortex (PMC), cingulate gyrus and basal ganglia (BG), the lateralization tendency was not obvious. The activation in cerebella is characterized with right lateralization. CONCLUSION: Though there are tiny differences among subjects, most of the motor areas appear lateralized activation. Past studies only observed laterality in several motor areas. It may be due to the difficulty of the task or the experimental design.