Findings of Perfusion MR Imaging in Acute Middle Cerebral Artery Territory Ischemic Stroke

BACKGROUND: Although a magnetic resonance imaging (MRI) is highly sensitive for changes associated with ischemic stroke, the detection of an acute ischemic lesion is usually impossible within 6 hours of the stroke onset on a conventional MRI. The perfusion MRI is a new imaging technique for diagnosing acute ischemic stroke. We evaluate the clinical usefulness of the perfusion MRI in predicting the final infarct extent in 18 patients with acute middle cerebral artery (MCA) territory ischemic stroke. METHOD: The perfusion MRI was performed within 6 hours after the stroke onset in all patients with a single-section dynamic contrast-enhanced T2*-weighted imaging in conjunction with a conventional routine MRI and MR angiography. Time-concentration curves and cerebral blood volume (CBV) maps were calculated from the dynamic MR imaging data by using numerical integration techniques. We compared findings of CBV maps with infarction on a follow-up CT or MRI. RESULTS: In 14 of 18 patients, the CBV in the occluded MCA territory were decreased. In the remaining 4 patients with a reversible ischemic neurologic deficit (RIND) or transient ischemic attack (TIA), the CBV were increased in 3 and normal in 1. Out of 14 patients with a decreased CBV, two had focal regions of increased CBV within the affected territory, indicating reperfusion hyperemia. The regions of increased or decreased CBV were eventually converted to infarction on follow-up images in all 14 patients. Out of 4 patients with RIND or TIA, one showed focal infarction in centrum semiovale on a follow-up image. CONCLUSIONS: The perfusion MRI was useful for the assessment of hemodynamic change about cerebral perfusion and may predict the extent of final infarction in acute MCA territory ischemic stroke. These results suggest that the perfusion MRI may play an important role in the diagnosis and management of acute ischemic stroke.

A Case of Cerebral Venous Thrombosis Associated with Minimal Change Nephrotic Syndrome

Nephrotic syndrome causes a hypercoagulable state, leading to both venous and arterial thrombosis. Thromboembolic events occur frequently in patients with nephrotic syndrome. However, central venous thrombosis occurs less frequently as a complication of minimal change nephrotic syndrome. The pathogenic mechanisms are not yet unclear, but various alterations in coagulant and anti-coagulant factors may be responsible. We report a case of cerebral venous thrombosis associated with minimal change nephrotic syndrome. A 27-year-old man was admitted due to sudden, severe headache with nausea and vomiting. He complained of a continuous throbbing-type headache in bifrontal area. One month prior to the symptoms, he was diagnosed as having nephrotic syndrome based on clinical manifestations and biopsy findings. The routine laboratory findings showed that he had hyperlipidemia, hypoalbuminemia and proteinuria. In clotting factor analysis, fibrinogen, factor VII, VIII and von Willebrand factor were increased and factor XII, antithrombin III and protein S were decreased. The unenhanced brain CT scan showed a triangle-shape high density in a superior sagittal sinus and gadolinium enhanced brain MRI showed unenhanced blood clot in a superior sagittal sinus. Initial brain MR venography showed a lack of filling of a superior sagittal sinus and poor visualization of cortical veins.

Correlation between Mirror Movements and Recovery of Motor Power in Stroke Patients

BACKGROUND: Mirror movement is common in young children, and it could be seen in normal adults. Several mechanisms including motor pathway reorganization involved in motor recovery after stroke. Motor pathway reorganization has been reported to be a mechanism in several studies of patients with mirror movement. However, the correlation of motor recovery and mirror movement has been debated. We studied the degree of mirror movement in stroke patients compared with a controlled group to look into their relationship. METHODS: Our controls were 50 adults without neurologic symptoms and signs. The hemiparetic group was comprised 94 patients who had incurred unilateral brain lesion: 36 patients were acute stroke patients, 58 patients were chronic stroke patients. Mirror movements were assessed by three different tasks: abduction of thumb, sequential finger tapping, and grasping. We analyzed mirror movements in controls and patients, and tried to find a correlation between the degree of mirror movement and the recovery of motor power in chronic stroke patients. RESULTS: In controls, male exhibited more frequent mirror movement than female at specific tasks, and there was no difference between tasks of right or left hand. In stroke patients, there was more mirror movement in the nonparetic hand than in the paretic one during the movement of contralateral hand. In acute stroke, the frequency of mirror movement had no variability according to the degree of motor power. The recovery of motor power at a late stage was not correlated with the degree of mirror movement. Consclusions: Motor pathway reorganization seems to be insignificant for motor recovery because the degree of mirror movement was not correlated with the recovery of motor power in this study.