Cerebral Blood Volume and Relative Perfusion Rate Mapping with Contrast Enhanced Gradient Echo Echo PlanarImaging

PURPOSE: To assess regional cerebral blood volume and perfusion rate by MR imaging. MATERIALS AND METHODS:Eight normal volunteers and one patient underwent MR imaging after bolus injection of a double dose ofgadoinium(0.2mMol/kg). Gradient-echo EPI pulse sequencing was used, with TR/TE 1500/40msec, flip angle 90o, matrixsize 256X128. One hundred sequential images at the same level were obtained. The time-signal intensity curve wasplotted and converted to a time-concentration ( R2) curve. Relative cerebral blood volume was determined, withintegration of time-concentration curve pixel by pixel. Perfusion rate was determined by calculating maximal slopeof the R2 curve and the time taken to attain this. RESULTS: On volume maps, clear differentiation of gray matter,white matter and major vessels was established. The mean gray and white matter ratio of blood volume was2.78+/-0.43. Slope and volume maps were similar, but in one patient perfusion was apparently greater on the ratemap than on the volume map. CONCLUSION: Cerebral blood volvme and slope map images reflect changes in cerebralhemodynamics. It is thought that these findings can be clinically applied to the determination of vascularity inbrain tumors and acute cerebral ischemia

MR Imaging of the Meniscofemoral Ligament: Incidence and classification

PURPOSE: To demonstrate the incidence and variation of the meniscofemoral ligament in Koreans. MATERIALS AND METHODS: A total of 100 MR studies of 95 patients were reviewed with special attention to the appearance and incidence of the meniscofemoral ligaments. The ligament of Wrisberg was classified according to proximal insertion: type I, insertion at the posterofemoral condyle ; type II, insertion at the distal portion of the posteriorcruciate ligament ; type III, insertion at the distal portion of the posterior cruciate ligament. On T2-weighted images, the high signal at the meniscal insertion of the meniscofemoral ligament was classified according to itsshape. RESULTS: The ligament o Humprey was observed in 17 cases and the ligament of Wrisberg was in 90:type I in41 cases;type II, 19 cases;type III, in 28 cases; unclassified, in 2 cases. In 77 cases, the cleft with high signal intensity was seen between the meniscofemoral ligament and the posterior cruciate ligament. CONCLUSION: From our results, the incidence of the ligament of Wrisberg on MRI was moe prevelant than the ligament of Humprey. An exact knowledge of the meniscofemoral ligament could be helpful in distinguishing it from pathologic lesions.