Sublethal irradiation and syngeneic bone marrow transplant prolong thyroid xenograft survival.
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Animals↗
Biomedical subjects
A A Moss
Publications and source records attributed to A A Moss.
Imaging of colorectal carcinoma.
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Colorectal Neoplasms↗
Cystic teratoma of the ovary: CT detection.
Computed tomography (CT) was performed in 38 patients with 41 benign cystic teratomas of the ovary and two patients with malignant transformation. CT depicted all tumors. The presence of fat in 40 of 43 cases (93%), tooth or calcification in 24 of 43 (56%), Rokitansky protuberance in 35 of 43 (81%), tufts of hair in 28 of 43 (65%), and a fat-fluid level in five of 43 (12%) allowed a definite diagnosis of ovarian cystic teratoma in 42 of 43 cases (98%). In the two cases of malignancy, single large (greater than 10 cm) plugs (with uptake of contrast medium in one) with a cauliflower appearance and an irregular border forming an obtuse angle with the inner wall of the cyst suggested malignant transformation. In three cases of benign cystic teratoma, a mucinous tumor (one benign, one borderline, one malignant) arising in the same ovary was seen at pathologic examination but was only diagnosed with the help of CT in two of three cases. Thickening of the tube was noted in two cases of torsion of the adnexa. CT findings were compared with findings at radiography of the abdomen and hysterosalpingography in 30 cases, ultrasound in 31, and magnetic resonance imaging in three. This study demonstrated that CT was the best procedure for imaging cystic teratomas of the ovary.
Adnexal Diseases↗
CT-guided aspirations for the body: comparison of hand guidance with stereotaxis.
Forty computed tomography (CT)-assisted aspirations performed with only hand guidance were prospectively compared with 40 performed with a CT body-stereotaxic system. Although there was no statistically significant difference in lesion size and path length between the two groups, use of stereotaxis compared with hand guidance decreased by 75% the number of needle manipulations required to place a needle within a lesion. With the stereotaxic method, only 43 needle manipulations were required to confirm a needle placement in 40 lesions, with no lesion requiring more than two attempts. Use of stereotaxis decreased the number of localization scans by 80% and biopsy time by 50%. It is concluded that CT-guided needle placements with hand guidance are often inaccurate and, unless the lesion is large, require multiple needle manipulations to place a needle within the lesion. Stereotaxis-guided biopsies, on the other hand, decrease radiation exposure, biopsy time, and trauma from multiple needle punctures.
Biopsy, Needle↗
Superficial- and deep-tissue temperature increases in anesthetized dogs during exposure to high specific absorption rates in a 1.5-T MR imager.
Superficial- and deep-tissue heating was measured in five dogs during high-specific-absorption-rate radiofrequency (RF) irradiation to see whether significant temperature changes could be produced by a 1.5-T clinical magnetic resonance imager. The RF power output employed was 6.3 times that required for routine imaging. Temperature probes were placed in both deep and superficial tissues, and temperatures were recorded before, during, and after exposure. In each dog, there was a linear temperature increase of several degrees during RF exposure; the maximal average change was 4.6 degrees C in the urinary bladder. The temperature increase was slightly greater in deep tissues than in superficial tissues. The calculated specific absorption rate, based on the temperature change, averaged 7.9 W/kg for all five dogs. These findings argue for continued caution in the design and operation of imagers capable of high specific absorption rates, particularly when they are used for imaging infants or patients with altered thermoregulatory capability.
Absorption↗
Peritoneal implants from ovarian tumors: CT findings.
Metastatic peritoneal implants were assessed preoperatively with computed tomography (CT) in 38 patients with ovarian tumors. In the 106 biopsy specimens of gross peritoneal implants and the 118 random biopsy specimens obtained from these patients, metastatic deposits were detected in 27 of 38 (71%) patients and in 104 biopsy sites. CT depicted metastatic lesions in 17 of 27 (63%) patients and in 63 of 104 (61%) biopsy sites. The three sites most commonly involved were the right subphrenic region, the greater omentum, and the pouch of Douglas. The usefulness of CT in detecting lesions depended mainly on the location of the implant and the presence of adjacent ascites, rather than on lesion size.
Adult↗
MR staging of bladder carcinoma: correlation with pathologic findings.
Forty patients with bladder carcinoma were examined preoperatively by means of magnetic resonance (MR) imaging. In all patients, total cystectomy with enterocystoplasty and pelvic node dissection was performed. The surgical and pathologic findings were correlated with the MR findings. Extension through the deep muscle of the bladder wall was present in 20 of the 40 patients and was diagnosed with a sensitivity of 95% and a specificity of 95%. Extension to perivesical fat was present in 18 of 40 patients and was diagnosed with a sensitivity of 66% and a specificity of 100%. Invasion of the adjacent organs was present in nine of 40 patients and was diagnosed with a sensitivity of 44% and a specificity of 96%. On the basis of the MR findings, the tumor was correctly staged, according to the TNM classification, in 24 of 40 (60%) patients, tumor extension was overestimated in three of 40 (7.5%) patients, and tumor extension was underestimated in 13 of 40 (32.5%) patients. MR imaging has been shown to be accurate in identification of macroscopic lymph node involvement and deep muscle involvement. It appears to be at least as useful as computed tomography (CT) in the evaluation of perivesical fat involvement and to be superior to CT in the detection of invasion of adjacent organs. One limitation of MR imaging is in the evaluation of tumor extension into the periurethral glands.
Adenocarcinoma↗
Cross-sectional imaging method. A system to compare ultrasound, computed tomography, and magnetic resonance with histologic findings.
Studies comparing imaging modalities require a precise knowledge of the type and location of tissue structures. When comparing cross-sectional techniques such as ultrasound, computed tomography, and magnetic resonance imaging, the images must be obtained through the same tissue section that is examined histologically. An experimental system that permits comparison of these modalities with histologic sections of precisely corresponding tissue is described. Application in 30 gastrointestinal tissue specimens shows a high degree of correspondence between cross-sectional images and histologic sections. This method should be useful in tissue imaging research for anatomic correlation and for comparisons between imaging modalities.
Digestive System↗
Classification and investigation of artifacts in magnetic resonance imaging.
Many MR artifacts are not understandable in terms of previous imaging experience. A variety of artifacts is presented here; their origins and elimination are discussed.
Diagnostic Imaging↗
Utility of ceruletide in promoting intestinal opacification for abdominal and pelvic computed tomography.
An analysis of the utility of parenteral ceruletide, a cholecystokinin-like synthetic decapeptide, in promoting bowel opacification for computed tomography (CT) scanning was performed. Abdominal and pelvic CT scans of 85 patients who had received intramuscular ceruletide following oral contrast administration and of 85 control patients were reviewed and the degree of bowel opacification evaluated. No significant advantage was conferred by ceruletide in opacifying the stomach or major part of the small intestine. However, a statistically significant difference was found between the 2 groups in the presence or absence of contrast in the terminal ileum and right colon. Contrast was detected in the terminal ileum in 52 experimental compared with 35 control patients (p less than 0.009) and in the right colon in 56 experimental and 39 control subjects (p less than 0.01). Intramuscular administration of ceruletide will be helpful when terminal ileal opacification is essential or in patients in whom colonic opacification is desired but rectal contrast contraindicated.
Ceruletide↗
Nuclear magnetic resonance of the liver, spleen, and pancreas.
This review includes the initial experience with NMR imaging of the liver, spleen, and pancreas at the University of California, San Francisco, using a prototype 0.35 Tesla system. This experience shows great promise for detection of hepatic metastases using T1-weighted pulse sequences. T2-weighted pulse sequences appear sensitive for detecting cavernous hemangioma of the liver and may allow tissue specific discrimination of the benign lesion from cancer. NMR is also suitable for evaluating diffuse metabolic alterations and is sensitive and specific for the diagnosis of iron overload. Detection of fatty liver requires use of chemical shift techniques as conventional NMR imaging pulse sequences are relatively insensitive. Motion artifacts and lack of an effective bowel contrast agent limits imaging of the pancreas and retroperitoneum, where CT remains the procedure of choice. The normal spleen has longer T1 and T2 relaxation times than liver or pancreas and NMR has not been successful in diagnosing splenic metastases or lymphoma on a routine basis. We conclude that NMR imaging will be valuable in the diagnosis of focal liver disorders; until fast scan techniques and effective magnetic contrast agents are available for oral and/or intravenous use, other abdominal applications will remain limited.
Adenocarcinoma↗
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.
Adipose Tissue↗
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 Hodgkin's lymphoma was detected as diffuse marrow infiltration with superimposed focal areas of even lower signal intensity, reflecting the nodular nature of Hodgkin's. These results indicate that infiltrative marrow disorders can be sensitively detected by MRI.
Adolescent↗
Pancreatic insufficiency: role of CT evaluation.
The medical records of all patients discharged over a 3-year period with a diagnosis of pancreatic insufficiency were reviewed. In some patients, abdominal radiographs or sonograms provided adequate information. However, computed tomography (CT) was a key diagnostic tool in understanding the cause of pancreatic insufficiency in 11 of the 13 patients in whom it was performed. CT study detected previously undiagnosed carcinoma in one patient, enabled diagnosis of chronic pancreatitis in five, confirmed complete surgical removal of the pancreas in two, and--despite optimal use of contrast material and 5-mm contiguous sections--was unable to detect any pancreatic tissue in three patients, suggesting complete idiopathic atrophy. Pancreatic insufficiency is a difficult clinical diagnostic problem. CT scanning should be employed early if abdominal radiographs or sonograms do not detect an abnormality.
Adult↗
Bowel migration in the normal fetus: US detection.
Ten fetuses underwent ultrasound scanning at 7-10 weeks gestational (postmenstrual) age. In all cases, an echogenic mass measuring 0.5-1.0 cm was demonstrated within the base of the umbilical cord at its insertion into the fetal abdomen. No area with echogenicity characteristic of the small bowel was identified within the lower part of the fetal abdomen. All fetuses were reexamined 4-12 weeks later, at which time the mass in the umbilical cord was no longer seen, and normal fetal bowel was visualized in the lower abdominal cavity of the fetus. This sequence of findings appears to represent the sonographic demonstration of normal fetal bowel migration early in gestation and should not be confused with defects of the abdominal wall such as omphalocele or gastroschisis.
Abdominal Muscles↗
Changing appearance of the normal uterus during the menstrual cycle: MR studies.
The authors obtained sagittal magnetic resonance (MR) images twice a week from six healthy women during one full menstrual cycle to establish the changes depicted in the uterine layers. Parallel endocrine and ultrasound studies were used to establish the day of ovulation precisely. Consistent changes in the thickness and intensity of the endometrium and myometrium wer noted in all subjects during the menstrual cycle. Both myometrial thickness and endometrial area increased linearly during the follicular (preovulatory) phase of the cycle; the rate of increase dropped significantly during the luteal phase. Two myometrial layers were observed; the best contrast between the layers was demonstrated during the first half of the cycle.
Adult↗
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.
Adolescent↗
CT body stereotaxic instrument for percutaneous biopsy and other interventive procedures: phantom studies.
This article describes a new body stereotaxic system that defines a fiducial point by means of a skin localization device placed directly on the patient. The system uses a rectilinear stereotaxic frame to guide the needles along the calculated path. A method for calculating paths that require angulations from one scan slice to another is described, as well. The system was tested in a foam phantom and shown to be intrinsically accurate in vitro to within 2 mm in both the x and y axis.
Biopsy, Needle↗