Magnetic resonance imaging in brainstem ischemic stroke

To evaluate the efficacy of magnetic resonance imaging in brainstem stroke, we studied 21 cases of clinically definite brainstem ischemic stroke with brain magnetic resonance imaging (MRI) and conventional computed tomography (CT). MRI demonstrated brainstem lesions in 79% of the cases (16.5 out of 21), while CT revealed 33% (7 out of 21) when cases with suspicious lesions counted as 0.5. Although MRI was done a few days later than CT in most cases, MRI was superior to CT in detecting the number and the size of ischemic lesions, with clear delineation of anatomy and visualization of the status of the blood flow in the vertebral-basilar artery. Disappearance of the flow signal void in the basilar artery can be an important clue in diagnosing occlusion or thrombus of the basilar artery. By delineating the extent and the location of the infarction, MRI findings allowed an interpretation of whether the ischemic vessel is a small basilar branch or a large vessel vertebral or basilar artery.

Autonomic Dysfunction Measured by Valsalva Ratio in Parkinson's Disease

As a clinical tool to evaluate autonomic dysfunction, "Valsalva ratio" was measured in 36 Parkinson's disease patients (15 men, 21 women) and 10 control subjects (4 men, 6 women). In this study, the Valsalva ratio was defined as the ratio of peak to nadir heart rate during Valsalva maneuver, namely voluntary and transient breathholding in maximal inspiration state with subsequent release by the subject. EKG was monitored throughout the whole process to observe the moment to moment change of heart rate. The subject group with Parkinson's disease was subdivided by clinical variables including sex, are, Hoehn and Yahr clinical stage, duration of symptoms, and duration of therapy with L-dopa containing drugs. The Valsalva ratio of the subject group as a whole was less than that of the control group (P<0.05). But the differences of Valsalva ratio between the subgroups graded by above clinical variables of Parkinson's disease were not statistically significant. The clinical applicability of "Valsalva ratio" measurement described in this study was discussed.