Biomedical subjects
Publications and source records attributed to M E Baker.
A hepatic adenoma (HA) nearly isointense to normal liver on short and long repetition and echo time spin echo pulse sequences is presented. Contrary to previous expectations, the case shows that a single hepatic mass with these signal characteristics on magnetic resonance without a scar may represent either HA or focal nodular hyperplasia.
Computed tomography is frequently used in the initial workup of patients with suspected aortic dissection to distinguish dissection involving the ascending aorta from dissection limited to the descending aorta. We reviewed CT of 19 patients who were proven by aortography to have normal ascending aortas. In eight patients the superior extension of the pericardium was visualized and thought to be a potential source of a false-positive diagnosis of type A aortic dissection.
The ability to distinguish between pleural and peritoneal fluid is important in the management of patients with peridiaphragmatic fluid collections. The differentiation of subphrenic fluid from pleural effusion by CT may be difficult and requires a detailed understanding of the normal appearance of the diaphragm on transaxial images. We report 12 patients in whom peridiaphragmatic fluid collections could potentially be misinterpreted as peritoneal rather than pleural fluid. In all cases the presence of subsegmental, basilar atelectasis with subpulmonic fluid created confusing CT images. Subsegmental atelectasis formed a curvilinear band at the lung base that simulated the hemidiaphragm. Fluid anterior to the atelectasis caused a false impression of subdiaphragmatic (peritoneal) fluid. Computed tomography through the upper abdomen excluded intraabdominal fluid in all cases. In four cases ultrasonography confirmed fluid in a supradiaphragmatic, subpulmonic location, excluded peritoneal fluid, and identified subsegmental atelectasis. The presence of subpulmonic fluid and subsegmental atelectasis requires meticulous interpretation of transaxial CT images to avoid the incorrect localization of peridiaphragmatic fluid collections.
OBJECTIVE: Our goal was to describe the abdominal CT findings in 52 patients with midgut carcinoid tumors and correlate these findings with their biochemical profiles. MATERIALS AND METHODS: Abdominal/pelvic CTs of 52 patients with midgut carcinoid tumors were reviewed retrospectively for the presence of liver metastases, mesenteric and peritoneal disease, bowel changes, lymphadenopathy, and the presence of the primary tumor. Logistic regression models were used to evaluate the association between these findings and the serum and platelet serotonin and urine 5-hydroxyindolacetic acid levels. RESULTS: The most common finding was hepatic metastases (34/52). Nonspecific mesenteric soft tissue stranding was present in 26 of 52 and a discrete mesenteric mass was present in 25 of 52. These masses had linear, radiating soft tissue spokes in 16 of 25 and contained calcification in 10 of 25. Retroperitoneal and mesenteric lymphadenopathy was present in 14 of 52 and 11 of 52 cases, respectively. Carcinomatosis was present in 11 of 52. Bowel wall thickening was seen in 9 of 52. Six patients had a small bowel obstruction. Elevated serum serotonin, platelet serotonin, and urine 5-hydroxyindolacetic acid levels were significantly associated with the presence of liver metastases (p = 0.0032, 0.0098, and 0.0450, respectively). Elevated platelet serotonin levels were also significantly associated with the presence of a mesenteric mass (p = 0.0101). CONCLUSION: In our population, the most common findings of a midgut carcinoid tumor are liver metastases, nonspecific mesenteric soft tissue changes, a discrete mesenteric mass with radiating soft tissue spokes, often containing calcification, and lymphadenopathy. As expected, liver metastases correlate strongly with the presence of elevated biochemical levels. A new observation is the correlation of elevated platelet serotonin levels and mesenteric masses. We hypothesize that platelet serotonin may be the factor that stimulates stromal cells to produce mesenteric fibrosis and mass formation.
OBJECTIVE: The purpose of this work was to determine the frequency and significance of characteristic nontumorous low attenuation defects found in the left hepatic lobe during CT arterial portography (CTAP). MATERIALS AND METHODS: Eighty CTAPs performed over a 17 month period were retrospectively reviewed to identify nonsegmental low attenuation defects adjacent to the falciform ligament, gallbladder, or porta hepatis. Twenty-four separate defects were present in 14 of 80 (18%) patients. Cases in which a defect was present were compared with MR, surgical findings, and pathology reports. RESULTS: The defects were oval or triangular in shape with a mean maximum diameter of 1.7 cm (range 1-5 cm). None of these defects were identified on MR in the 12 patients who underwent T1, T2, and STIR MR; however, 3 showed dropout of signal on chemical shift MR, suggesting fatty infiltration. In the 12 patients who underwent surgery, no lesion was shown to represent tumor. Two intraoperative biopsies of the area of the defects showed fatty infiltration. CONCLUSION: Nontumorous low attenuation defects adjacent to the gallbladder, falciform ligament, or porta hepatis are a pitfall of CTAP and can be associated with focal fatty infiltration, as well as decreased perfusion due to technical factors or a variation in hepatic vascular supply.