Proton MR Spectroscopic Features of the Human Liver: In-Vivo Application to the Normal Condition

PURPOSE: To determine the feasibility of MR spectroscopy in the living human liver, and to evaluate thecorresponding proton MR spectroscopic features. MATERIALS AND METHODS: In fifteen normal volunteers with neitherprevious nor present liver disease the proton MR spectroscopic findings were reviewed. Twelve subjects were maleand three were female ; they were aged between 28 and 32 (mean, 30) years. MR spectroscopy involved the use of a1.5T GE Signa Horizon system with body coil (GE Medical System, Milwaukee, U.S.A). We used STEAM (STimulatedEcho-Aquisition Mode) with 3000/30 msec of TR/TE for signal acquisition, and the prone position withoutrespiratory interruption. Mean and standard deviation of the ratios of glutamate + glutamine/lipids,phosphomonoesters/ lipids, and glycogen + glucose/lipids were calculated from the area of their peaks. RESULTS:The proton MR spectroscopic findings of normal human livers showed four distinctive peaks, i.e. lipids, glutamateand glutamine complex, phosphomonoesters, and glycogen and glucose complex. The mean and standard deviation of theratios of glutamate + glutamine/lipids, phosphomonoesters/lipids, and glycogen + glucose/lipids were 0.02 +/- 0.01,0.01 +/- 0.01, and 0.04 +/- 0.03, respectively. CONCLUSION: In living normal human livers, MR spectroscopy can besuccessfully applied. When applied to a liver whose condition is pathologic, the findings can be used as astandard.

Wall Thickening of The Gastric Antrum: Is It a Pseudolesion or a Tumor?

PURPOSE: To demonstrate the two-phase spiral CT features of pseudo-wall thickening and tumor in the gastricantrum, and to evaluate the possibility of differential diagnosis by analyzing two-phase spiral CT scans. MATERIALS AND METHODS: We retrospectively reviewed 120 cases in which two-phase spiral CT scans showed focal wallthickening in the prepyloric antrum of the stomach. Our series included 60 cases of gastric cancer (includingseven of early gastric cancer) and 60 cases of normal prepyloric antrum. All patients underwent two-phase spiralCT and upper gastrointestinal series (n=83) and/or gastric endoscopy (n=80). All cancer cases were confirmed bybiopsy (n=60). We evaluated the differential points between gastric cancer and pseudo-wall thickening of thegastric antrum. RESULTS: The mean thickness of the antral wall was 19.0mm in the cancer group and 12.5mm in thenormal group. Thirty-one cases (51.7%) in the cancer group and 51 (85.0%) in the normal group showed concentricwall thickening, while in each group, the remainder showed eccentric wall thickening. The common enhancementpatterns of thickened wall in the cancer group were 1) a thick enhanced mucosal layer during the arterial phase,with diffusely enhanced whole wall thickness during the venous phase (n=21); 2) a thick enhanced mucosal layerduring the arterial phase, with thicker and more intense enhancement of the same area during the venous phase(n=18). In the normal group, the common enhancement pattern was a thin enhanced mucosal layer during both thearterial and venous phase (n=34). In the cancer group, the common associated findings were regionallymphadenopathy (n=43) and food remnants in the stomach (n=15), and in the normal group, intraluminal normalmucosal folds in the thickened segment (n=50). The findings of food remnants despite overnight fasting andintraluminal normal folds occurred only in the cancer and normal group, respectively. CONCLUSION: Pseudo-wallthickening frequently showed thin enhancement of the mucosal layer on both the arterial and venous phases oftwo-phase spiral CT scan; a tumor frequently showed a thick enhanced mucosal layer during the arterial phase, withdiffusely enhanced whole-wall thickness during the venous phase or a thick enhanced mucosal layer during thearterial phase, with thicker and more intense enhancement of the same area during the venous phase. The finding ofthin and homogeneously enhanced intraluminal normal mucosal folds in the thickened segment strongly suggested thatthe lesion was a pseudo-lesion.

Comparison of Magnetization Transfer Ratios of Various Cerebral Edemas

PURPOSE: To compare magnetization transfer ratios (MTR) among various cerebral edemas with different pathophysiologic processes. MATERIALS AND METHODS: Cerebral edemas seen on MR images in 45 patients were classified as one of three types: vasogenic (n=22; tumor[n=9], contusion[n=3], hemangioma[n=4], hemorrhage[n=4], others[2]); cytotoxic (n=18; all acute infarction), and interstitial edema (n=5). In all cases, both T2-weighted images with and without magnetization transfer were obtained using off-set pulses of 600Hz. MTRs in each cerebral edema were measured and compared. RESULTS: The mean MTRs of vasogenic edema, cytotoxic edema and interstitial edema were 22 +/- 5%, 26 +/- 4 % and 19 +/- 2%, respectively. There was no statistically significant difference among the three types (p>0.05). CONCLUSION: Mean MTR was highest in cytotoxic edema and lowest in interstitial edema, but the differences were not significant.

Comparative study of radiologic findings in reduced and nonreduced intussusception by barium enema

One hundred and eighty one cases, which comfirmed tobe intussusception, were reviewed retrospectively to identify the differences between radiologic findings of reduced and nonreduced intussusceptions by barium enema. The number of cases of reduced intussusception was 148 and nonreduced was 33, so the rate of reduction was 82%. On conventional radiographs, air-fluid levels were seen in 23 cases(15.5%) of the reduced intussusception and in 18 cases(54.6%) of the nonreduced intussusception, and soft tissue masses were seen in 20 cases(13.5%) of the reduced intussusception and in 2 cases(36.4%) of the nonreduced intussusception. The mean value of a ratio of maximal diameter of small bowel to interpedicular distance of L3vertebral body was 0.93 in the reduced intussusception and 1.25 in the nonreduced intussusception. On barium enema, the dissection sign was seen in 33.1% of the reduced intussusception and in 75.8% of the nonreduced intussusception. The morphologic abnormalities of ascending colon were seen in 11.5% of the reduced intussusception and in 38.7% of the nonreduced intussusception. So, the findings of the air-fluid level soft tissue mass, marked small bowel dilatation, dissection sign and morphologic abnormality of ascending colon were more frequently seen in the nonreduced intussusception than the reduced cases. There was no correlation between the location of intussusceptum and the reduction rate.