Acute-onset migrainous aura mimicking acute stroke: MR perfusion imaging features.

BACKGROUND AND PURPOSE: In a very limited number of cases, acute migrainous aura may mimic acute brain infarction. The aim of this study was to recognize patterns of MR perfusion abnormalities in this presentation. MATERIALS AND METHODS: One thousand eight hundred fifty MR imaging studies performed for the suspicion of acute brain infarction were analyzed retrospectively to detect patients with acute migrainous aura not from stroke. All patients were examined clinically by 2 neurologists and underwent a standard stroke MR imaging protocol, including PWI. Two radiologists reviewed the perfusion maps visually and quantitatively for the presence, distribution, and grade of perfusion abnormalities. RESULTS: Among 1850 MR imaging studies, 20 (1.08%) patients were found to have acute migrainous aura. Hypoperfusion was found in 14/20 patients (70%) with delayed rMTT and TTP, decreased rCBF, and minimal decrease in rCBV. In contrast to the typical pattern in stroke, perfusion abnormalities were not limited to a single vascular territory but extended to >1. Bilateral hypoperfusion was seen in 3/14 cases. In 11/14 cases, hypoperfusion with a posterior predominance was found. TTP and rMTT were the best maps to depict perfusion changes at visual assessment, but also rCBF maps demonstrated significant hypoperfusion in quantitative analysis. In all patients, clinical and imaging follow-up findings were negative for stroke. CONCLUSIONS: Acute migrainous aura is rare but important in the differential diagnosis among patients with the suspicion of acute brain infarction. Atypical stroke perfusion abnormalities can be seen in these patients.

[Time-resolved contrast-enhanced MR angiography of the lower limbs: solving the problem of venous overlap]. / Zeitaufgelöste MR-Angiografie der Becken-Bein-Etage: ein Lösungsansatz für das Problem der venösen Überlagerungen.

PURPOSE: The aim of this retrospective study was to evaluate peripheral MRA using time-resolved measurements at the femoral as well as the calf level with regard to the presence of unwanted venous overlap. MATERIALS AND METHODS: 150 patients were examined using a 1.5 T MRI unit for a three-step CE MRA approach with three partial injections of contrast agent (0.1 mmol/kg body weight of 1 molar contrast agent). Dynamic time-resolved measurements were used at the femoral as well the calf level. The images were analyzed with respect to the presence and grade of unwanted venous overlap as well as inadequate bolus timing. RESULTS: In all cases, MRA was technically successful. The overall image quality was assessed as excellent in 127 / 150 cases (84.7%), as mildly limited in 21 cases (14%) and as moderately limited, but still diagnostic in 2 cases (1.3%). No obvious overlap was found in 139 of 150 cases (92.7%). Non-diagnostically relevant minor overlap was found in 7 cases (4.6%) and non-diagnostically relevant moderate overlap in 4 cases (2.7%). Relevant venous overlap did not occur. Those 11 cases with minor or moderate overlap occurred at the calf level in 8 cases, at the calf and femoral level in 2 cases and at the femoral level only in one case. In 10 out of 11 cases, peripheral artery occlusive disease was classified as category IV (Fontaine). CONCLUSION: Three-step time-resolved CE MRA with dynamic measurements at the calf as well the femoral level can be considered as a safe and accurate technique for MRA of the lower limbs without significant venous overlap and without risk of inadequate bolus timing. Furthermore, it solves the problem of run time differences.

BLADE in sagittal T2-weighted MR imaging of the cervical spine.

BACKGROUND AND PURPOSE: Image quality and diagnostic reliability of T2-weighted MR images of the cervical spine are often impaired by several kinds of artifacts, even in cooperative patients. The aim of this study was to evaluate if BLADE sequences might solve these problems in a routine patient collective. MATERIALS AND METHODS: TSE and BLADE sequences were compared in 60 patients for T2-weighted sagittal imaging of the cervical spine. Image sharpness, motion artifacts, truncation artifacts, metal artifacts, CSF flow phenomena, contrast of anatomic structures (vertebral body/disk, spinal cord/CSF), and diagnostic reliability of spinal cord depiction were evaluated by 2 independent readers. Another 2 readers selected the sequence they would prefer for diagnostic purposes. Statistical evaluations were performed by using the Wilcoxon and the chi(2) test; differences with P < .05 were regarded as statistically significant. RESULTS: BLADE was significantly superior to TSE regarding image sharpness, image contrast, diagnostic reliability of spinal cord depiction, motion artifacts, CSF flow phenomena, and truncation artifacts; for metal artifacts no significant improvements were found. In 50 of 60 patients, BLADE was preferred for diagnostic purposes, and TSE was favored in 3 patients. The number of examinations that were nondiagnostic due to impaired spinal cord depiction was reduced from 12 in TSE to 3 in BLADE, and nondiagnostic examinations due to overall motion artifacts were reduced from 2 to 1. CONCLUSIONS: Using the BLADE sequence for sagittal T2-weighted imaging of the cervical spine proved to be advantageous to reduce various kinds of artifacts.