Albert A. Moss

Abnormal Body Fat Distribution Detected by Computed Tomography in Diabetic Men

Previous studies of body fat using tape measurement of body circumference and hand-held caliper skinfold measurements have suggested abnormal fat distribution in patients with diabetes mellitus. These methods, however, have high interobserver variability and cannot assess intra-abdominal fat independent of subcutaneous fat. We used computed tomography to evaluate body fat distribution in a group of 53 Japanese-American men of similar age and body mass index (weight divided by height squared). As determined by a 75-g oral glucose tolerance test, 29 subjects had type II diabetes and 24 were normal. Computed tomography cuts were obtained at three body levels to measure thorax, abdomen, and thigh subcutaneous fat area as well as intra-abdominal fat area. We found greater intra-abdominal fat in men with diabetes than in those without (123.74 vs. 95.54 cm2, P = 0.034) and a greater ratio of thorax to thigh subcutaneous fat (2.55 vs. 1.88, P = 0.016). These findings support the hypothesis that fat in different areas of the body differs metabolically. Computed tomography can be a useful tool for investigating whether abnormal body fat distribution is associated with the pathogenesis of abnormal glucose tolerance.

Magnetic resonance imaging of the bone marrow in patients with leukemia, aplastic anemia, and lymphoma

Magnetic resonance imaging (MRI) of the bone marrow was performed in 29 patients with leukemia, aplastic anemia, or lymphoma who were scheduled for bone marrow transplantation, and in 12 normals. T1-weighted coronal images (TR600/TE40) of the pelvis and proximal femurs demonstrated marrow pathology in adult patients. A simple MR grading system was developed to classify patterns of marrow involvement, and MR grading of cellularity was correlated with marrow histology. Normal marrow produced a relatively high signal intensity reflecting the predominance of short T1 fat in the marrow space. MRI of pretransplant patients with chronic myelogenous leukemia and acute leukemia in relapse demonstrated a markedly decreased marrow signal, consistent with the replacement of marrow fat by longer T1 neoplastic tissues. Aplastic anemia could not be differentiated from normal with the pulse sequences employed. Marrow involvement by Hodgkins lymphoma was detected as diffuse marrow infiltration with superimposed focal areas of even lower signal intensity, reflecting the nodular nature of Hodgkins. These results indicate that infiltrative marrow disorders can be sensitively detected by MRI.

Ultrasonic characteristics of frozen liver

The recent development of new ultrasound probes has made real-time intraoperative monitoring of cryosurgery, and thermocouple placement a possibility. It is shown that frozen tissue and thermocouple needles have acoustic characteristics that enable them to be easily visualized by ultrasound examination. Further in vivo animal studies are needed to examine temperature characteristics of visualized cryolesions, to develop scanning techniques, and to correlate ultrasonic findings with histologic changes in tissue.

Use of Computed Tomography in Diagnosing the Cause of Primary Aldosteronism

Abstract We performed computed tomography (CT) in 22 consecutive patients with primary aldosteronism to evaluate the usefulness of this technique in diagnosing and locating aldosterone-producing ad...

Resection of gastrinomas

Exploratory laparotomy and a search for gastrinomas was performed in 52 patients with the Zollinger-Ellison syndrome (ZES). Gastrinoma tissue was resected in 11 patients (21%), 6 (12%) of whom appear to have been cured. After surgery, serum gastrin levels in these six patients have remained normal from 10 months to 10 years. In the 46 other patients, tumor was unresectable because of metastases or multiple primary tumors (21 patients; 40%) or inability to find the tumor at laparotomy (21 patients; 40%). Multiple pancreatic islet cell adenomata were found in six of seven patients with multiple endocrine neoplasia (MEN), indicating that patients with this condition usually have diffuse involvement of the pancreas. The results of CT scans correlated with findings at laparotomy in 13 of 16 patients. The smallest tumor detected by CT scans was 1 cm in diameter. CT technology is more accurate in finding gastrinomas now than in the past and has a useful role in pre-operative evaluation. The possibility of resection should be seriously considered in every patient with Zollinger-Ellison syndrome. Abdominal CT scans, transhepatic portal venous sampling, and laparotomy should be used to find the tumor and to determine whether it is resectable. Using presently available methods, it should be possible to cure about 25% of patients with gastrinomas who do not have MEN and over 70% of those without MEN who appear to have a solitary tumor. Total pancreatectomy may be necessary to cure some patients with MEN, but that operation is rarely justified. The morbidity and mortality of surgical attempts at curing this disease have become minimal; we have had no deaths or serious complications following such operations in over 10 yrs. Total gastrectomy and indefinite use of H2-receptor blocking agents are the therapeutic options for patients with unresectable gastrinomas. Because H2-receptor blocking agents fail to control acid secretion in many patients after several yrs of therapy, total gastrectomy is indicated in a large proportion of patients whose tumors cannot be resected. Total gastrectomy in patients with ZES is also safe using current techniques; our last death following this operation for ZES occurred 15 yrs ago.

Noninvasive quantitation of liver iron in dogs with hemochromatosis using dual-energy CT scanning.

The concentration of iron deposited in the livers of two dogs with experimentally induced iron overload was determined by use of dual energy computerized tomographic (CT) scanning. A phantom was constructed, containing known amounts of iron-dextran solutions. CT scans of the phantoms, at 80 and 120 kVp, corrected for the response of water, showed a linear relationship between known iron concentrations and difference in CT number at the two scanning energies, with a change of 24 H units per 1000 mg% iron. Using the graph of this linear relationship, the amount of iron in dog liver was predicted, compared with the amount of iron measured from biopsy specimens, and analyzed by neutron activation analysis. A close correlation existed between predicted liver iron and measured iron concentration (r = 0.99). Dual-energy CT scanning appears to provide an accurate, noninvasive method of quantitating liver iron.

Determination of liver, kidney, and spleen volumes by computed tomography: an experimental study in dogs.

Abstract: The volume of the dogs liver, kidneys, and spleen were measured by computed tomography (CT) and a water displacement method. Organ volume determination by CT is a rapid, simple procedure that is accurate to ±5% of the organ volume measured by water displacement. Individual measurements were reproducible to within ±3%. Determination of organ volume has potential importance in a variety of clinical situations.

Value of computed tomography in the detection and staging of recurrent rectal carcinomas.

We studied a series of 39 patients who underwent computed tomog-raphy (CT) of the pelvis and abdomen following surgery for adenocarcinoma of the rectum. Based on the CT findings. recurrent rectal carcinoma was classi-fied into one of four stages: Stage I, intraluminal mass without colon wall thickening; Stage II. colon wall thickening (greater than 1 cm) without invasion of adjacent structures; Stage IIIA. thickening of the colon wall with direct invasion of adjacent organs but not the pelvic sidewalls; Stage IIIB, extension of mass to pelvic sidewalls; and Stage IV, distant metastatic disease. All 30 patients with recurrent rectal carcinoma had positive CT scans. Overall accuracy was 95% with 0% false negative and 5% false positive interpretations. Results indicate that CT is an accurate method of detecting and staging recurrent rectal carcinoma and for aiding the selection of appropriate therapy.

The Relation of Liver Fat to Computed Tomography Numbers: A Preliminary Experimental Study in Rabbits

The relation of liver fat content to CT number was studied in 20 rabbits (17 experimental, 3 control), where fatty degeneration was produced by carbon tetrachloride (CCl4) ingestion. Liver scanning was performed before and 2--5 days after CCl4 administration.. Changes (decrease) in CT number were compared with triglyceride (TG), water, and protein content of resected livers. A decrease of 12--20 CT numbers (24--40 H) reflected a TG concentration of 20--40 mg/g.

Dilute oral iron solutions as gastrointestinal contrast agents for magnetic resonance imaging; Initial clinical experience

Delineation of the gastrointestinal tract in magnetic resonance imaging (MRI) remains a problem. Ferric ammonium citrate is paramagnetic, producing a high MRI signal intensity by virtue of its spin-lattice (T1) relaxation rate enhancement properties. Water is diamagnetic, producing a low MRI signal intensity, especially with short TR and TE times. To compare efficacy for gastrointestinal contrast alteration, ferric ammonium citrate was administered to 18 patients and water was given to 10 patients. Spin-echo imaging at 0.35T was performed after administration of these agents. Ferric ammonium citrate produced high signal intensity within the esophagus, stomach, duodenum, and small intestine that aided in the differentiation of the gastrointestinal tract from adjacent tumors, vessels, and viscera. Delineation of the gut wall was superior using ferric ammonium citrate compared to that produced by water. Delineation of the margins of the pancreas, liver, and kidney from adjacent gastrointestinal tract was also better with ferric ammonium citrate. Optimal distinction between bowel and fat was better with water. Longer TE times (75 to 200 ms) may allow improved contrast between gut and intrabdominal fat using ferric ammonium citrate.