Comparison of Clinical Application Modes of 3D TOF MR Angiography in the Brain: Normal Volunteers Study

PURPOSE: To compare the various imaging techniques including application of magnetization transfer(MT), administration of IV contrast materials, and imaging time after injection of contrast materials in 3D time-of-flight(TOF) cerebral magnetic resonance angiography(MRA) in normal volunteers. MATERIALS AND METHODS: Each of 11 healthy volunteers was prospectively studied with 3D TOF cerebral MRA using various imaging parameters. Various parameters of 3D TOF MRA were 1) pre-enhanced magnetization transfer(MT), 2) postenhanced MT, immediate phase, 3) postenhanced MT, 10-minutes delayed phase, 4) postenhanced MT, 20-minutes delayed phase, 5) pre-enhanced non-MT, 6) postenhanced non-MT, immediate phase, 7) postenhanced non-MT, 10-minutes delayed phase, 8) postenhanced non-MT, 20-minutes delayed phase. Image qualities of various parameters were compared with regard to depiction of cerebral arteries and veins by visual assessment For statistical analysis paired t-test was used. RESULTS: In pre-enhanced MRA, images with MT mode were better in arterial visualization than those with :n0n-MT mode(p<0.01). Postenhanced MT and non-MT images were better in arterial and venous visualization !than pre-enhanced MT and non-MT images(p<0.01), respectively. Images obtained immediately after injection of contrast material were better in both arterial and venous visualization than delayed images(p<0.01). CONCLUSION: Postenhanced cerebral 3D TOF MRA with MT obtained immediately after injection of contrast materal is the best to increase visualization of both cerebral arteries and veins, and may be indicated in some cranial vascular diseases.

Gray Matter Heterotopias: MR and Clinical Features

PURPOSE: To evaluate types of gray matter heterotopias, associated brain anomalies, and its correlation with the patterns of seizure. MATERIALS AND METHODS: We evaluated retrospectively 19 patients(male :female=10:9, mean age 21 years) with gray matter heterotopias on brain MRI. Using 1.0T superconducting MR unit, spin echo TI-, proton-density- and T2-weighted images in axial, coronal and sagittal planes were obtained. RESULTS: Types of gray matter heterotopias were single subependymal in four patients, multiple subependymal in one, focal subcortical in eight, diffuse subcortical in two, mixed multiple subependymal and focal subcortical in four. Associated anomalies were seen in 11 patients:other neuronal migration anomalies in eight patients, corpus callosum agenesis in two, and combined holoprosencephaly and Dandy-Walker malformation in one. Fifteen patients had seizure. The patterns of seizure were not correlated with the types of heterotopias. CONCLUSION: In addition to subependymal, focal subcortical, and diffuse subcortical types, gray matter heterotopias included mixed variant of of multiple subependymal and subcortical type. Schizencephaly was the most common form of accompanying anomalies, and patterns of seizure were not correlated with types of gray matter heterotopias, even though main clinical menifestation was seizure.

MR Features in Lymphedema and Phlebedema of Extremities

PURPOSE: Authors analyzed the MR findings of swollen extremities to evaluate the MR features of lymphedema and phlebedema. MATERIALS AND METHODS: We reviewed MR imagings of 17 cases of swollen extremities, including 12 lymphedemas and 5 phlebedemas. We obtained axial TI-, T2-, and Gd-DTPA enhanced T1WIs using 1.0T superconducting magnet and measured cross-sectional areas of subcutaneous and subfascial tissues of a slice with grossly largest cross-sectional area using perimeter. We also analyzed changes in the signal intensities of the subcutaneous and subfascial tissues on T2WI, presence of enhancement on Gd-DTPA enhanced T1WI, and presence of skin thickening. RESULTS: Both subcutaneous and subfascial tissues of swollen extremities were increased in the cross-sectional areas than those of contralateral normal side. The subcutaneous compartment in lymphedema was statistically significantly increased in cross-sectional area than subfascial compartment in lymphedema(p<0.005) and subcutaneous tissue in phlebedema(p<0.05). Increased signal intensities and characteristic "honeycomb appearance" of subcutaneous tissue in the lymphedema were specific findings on T2WI. CONCLUSION: MR imaging was useful and noninvasive method in the diagnosis of swollen extremities. There were increased cross-sectional area of subcutaneous compartment with "honeycomb appearance" in lymphedema and increased signal intensities of both subcutaneous and subfascial compartment in phlebedema on the T2WI.