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Biomedical subjects

S E Seltzer

Publications and source records attributed to S E Seltzer.

At least 73 records · Page 4Linked to original sources
PubMed1987

Analysis of the tethered-bowel sign on abdominal CT as a predictor of malignant ascites.

The value of the "tethered-bowel sign" as a predictor of the nature of intraabdominal fluid was assessed. In the presence of moderate amounts of abdominal fluid, the sign was said to be positive if small or large bowel loops were not seen to float freely on computed tomographic (CT) images, and did not make contact with the anterior abdominal wall. A positive sign was significantly associated with the presence of malignant cells in the fluid (P less than 0.005). When equivocal cases were excluded, the sign had a sensitivity of 85%, a specificity of 93%, and an accuracy of 88%. In the study population (64% prevalence of malignant fluid), the sign had a positive predictive value of 96%, but a negative predictive value of only 78%. When equivocal cases were included, the sensitivity dropped to 69%, the specificity to 78%, and the accuracy to 72%. It is concluded that CT evidence of tethered-bowel loops strongly suggests a malignant cause of ascitic fluid.

Adult↗
PubMed1987

Modern imaging of the masseter muscle: normal anatomy and pathosis on CT and MRI.

Tremendous advances in diagnostic imaging technology have produced computed tomography (CT) and magnetic resonance (MR) imaging--new ways to depict the normal anatomy and pathosis of the masseter muscle. This article reviews the masseter muscle's normal appearance on CT and MR images and demonstrates the clarity with which CT, in particular, is able to depict soft tissue lesions and neighboring bony involvement. Analysis of the strengths, weaknesses, and availability of these new techniques leads to the conclusion that CT is currently the test of choice for imaging masseteric lesions but that MR shows greater promise for the future.

Adult↗
PubMed1987

The production and evaluation of contrast-carrying liposomes made with an automatic high-pressure system.

An automatic, high-pressure system (Microfluidizer) has been found useful for producing contrast-carrying liposomes on an industrial scale. The goal of this investigation was to determine the feasibility of using this new microemulsification process to manufacture contrast-carrying microemulsified liposomes (MELs). Seven contrast media (three ionic, four nonionic) were encapsulated into the MELs. Light and electron microscopy, light scattering, radioisotope, and CT scan techniques were used to characterize these MELs, and the contrast entrapments among the studied media were compared. The contrast-carrying MELs had good properties for imaging normal reticuloendothelial tissues, selectively. They had a narrow size range (0.1-3.0 micron), a single bilayer wall, high liver and spleen upake, and low leakage rates. The nonionic media were significantly more effectively entrapped in the MELs than the ionic media (P less than .05). The iodine-to-lipid weight ratio was about 1:16 for ionic media and 1:4 for nonionic media. Physical properties of the contrast media such as osmotic pressure and charge appeared to affect contrast entrapment. It was concluded that the microemulsification process is a useful system for producing contrast-carrying liposomes continuously, on a large scale and in a reproducible manner.

Animals↗
PubMed1987

Characterization of liposomes containing iodine-125-labeled radiographic contrast agents.

Multilamellar liposomes were prepared containing either iodine-125-labeled (125I) diatrizoate or 125-I labeled iotrol in their aqueous phase. The in vitro permeabilities of liposomes containing both contrast agents were measured in the presence of saline and serum at 37 degrees C. Two different phospholipid compositions were studied: phosphatidylcholine/cholesterol/stearylamine (PC/C/S, 8: 1:1 molar ratio) and distearoylphosphatidylcholine/sphingomyelin (DSPC/SM, 5:2 mole ratio). In saline, similar permeabilities were observed for the four phospholipid-contrast agent combinations. In serum, however, leakage of 125I activity was 2 to 3 times greater from PC/C/S liposomes than from vesicles composed of DSPC/SM. When PC/C/S liposomes that contained 125I-diatrizoate were injected into rats, the clearance half-times for 125I activity from the liver, spleen, and whole body were 4.4 hours, 4.5 hours, and 2.8 hours, respectively. Liposomes composed of DSPC/SM cleared at a significantly slower rate from the liver, spleen, and whole body with half-times of 24.0 hours, 18.4 hours, and 17.2 hours observed from these tissues, respectively.

Animals↗
PubMed1987

Gaining insight: improved images enhance understanding.

The past several decades have witnessed dramatic advances in the technology of image acquisition and display. There have been some parallel but less spectacular advances in understanding human acquisition and analysis of visual information. For the first time, imaging devices are available that allow the operator to determine the brightness relationships between normal and pathologic structures. For the first time too, it is becoming possible for the community of scientists interested in medical imaging to marry knowledge of human observer performance with the capabilities of the modern display devices to permit maximum information extraction from medical images.

Adenocarcinoma↗
PubMed1986

Malignant mesothelioma with brain metastases.

Although malignant mesothelioma is known to spread hematogenously, brain metastases are rare. In the patient presented herein, multiple unilateral symptomatic central nervous system metastases developed that were diagnosed by computed tomography and documented at autopsy. Since malignant mesothelioma is occurring more frequently in the population at risk (asbestos workers), this complication may be observed more commonly in the future.

Brain↗
PubMed1986

Organ envelopment in lymphoma visualised by computed tomography.

In 12 patients computed tomography revealed an unusual pattern of lymphomatous growth resulting in envelopment or engulfment of an organ. The kidneys were involved in eight cases, and the mediastinum and pericardium, oesophagus, stomach and rectosigmoid colon, and psoas muscle in one case each. Ten patients had non-Hodgkin's lymphoma and two had Hodgkin's disease; in every case, lymphomatous masses surrounded but did not destroy the affected tissues. The potential for both Hodgkin's and non-Hodgkin's lymphomas to enwrap both renal and non-renal tissues has not previously been emphasised.

Adult↗
PubMed1986

Hepatocellular carcinoma presenting as primary extrahepatic mass on CT.

Seven cases of hepatocellular carcinoma (hepatoma) (HCC) presenting as primary extrahepatic masses on CT are reported. All cases were diagnosed at the time of percutaneous biopsy, surgical resection, or autopsy. In none of the cases was the final diagnosis of HCC prospectively suspected on the basis of clinical and radiologic findings. Although three of the patients were at higher risk for development of HCC because of their medical histories, the absence of an elevated serum alpha-fetoprotein level and the extrahepatic location of the masses by CT suggested other disease. This variable pattern of radiologic presentation of HCC should be kept in mind during the evaluation of patients with suspected HCC, or when the findings on abdominal/pelvic CT of mass and presumed hepatic metastases are at variance with the clinical presentation.

Abdominal Neoplasms↗
PubMed1986

CT diagnosis of adrenal abnormalities in patients with primary non-adrenal malignancies.

Fifty-seven patients with primary non-adrenal malignancy were found to have unsuspected adrenal abnormality on CT. In 33, comparison of histopathologic findings and/or the patients' hospital course or follow-up lead to the diagnosis of adrenal metastases (23), benign non-functioning adenomas (7), metastasis with hyperplasia (1), benign hyperplasia (1), and fatty infiltration (1). The analysis of CT findings indicated that: I) A heterogeneous adrenal mass showing contrast enhancement was always metastatic, II) Nonfunctioning adenomas were always 3 cm or smaller in diameter, III) Bilateral adrenal masses and growth of adrenal mass on follow-up CT or regression on treatment indicated metastases, and IV) metastatic disease could not be excluded purely on the basis of the size of the adrenal mass.

Adrenal Gland Neoplasms↗
PubMed1986

Incidentally discovered mass of the adrenal gland.

Increasing numbers of asymptomatic masses of the adrenal gland are being discovered by high resolution computed tomography (CT) scanning. The significance of these masses and the question of further evaluation or treatment, or both, have posed a dilemma. From 1976 to 1983, an incidental finding of adrenal gland mass was identified in 88 patients undergoing abdominal CT scanning for unrelated problems. Adrenelectomy was performed upon 23 patients (26 per cent), including three adenomas (2.5, 3.0 and 6.5 centimeters), five carcinomas of the adrenal gland (6 to 20 centimeters), two hyperplasias and three adenocarcinomas of unknown origin. Thirty-eight (43 per cent) of the nonfunctioning masses were observed with repeat scans for an average of 25.1 months (three to 60 months), revealing no change in size. Twenty-seven patients (31 per cent) were lost to follow-up study. Silent primary (nonmetastatic) masses 3.5 centimeters or less manifested benign behavior without exception. Based upon these data, we conclude that all solid metabolically inactive lesions in the adrenal glands greater than 3.5 centimeters on CT abdominal scan deserve exploration. Lesions less than 3.5 centimeters may be safely followed with serial CT scans.

Adenocarcinoma↗
PubMed1985

Computed tomography of the hindfoot with rheumatoid arthritis.

We are performing direct, coronally oriented computed tomographic (CT) scans of the subtalar joint in patients with rheumatoid arthritis. To date, 16 examinations have been performed in 14 patients, 5 of whom were scheduled to undergo subtalar arthrodesis. Scans were 4-7-mm thick and spanned the length of the subtalar joint. CT scans depicted and localized subtalar abnormalities clearly and precisely. On CT scans, patients showed a characteristic constellation of abnormalities including: soft tissue swelling, cartilage space narrowing, bony erosions, and a pes planovalgus alignment abnormality (consisting of increased heel valgus angulation, and a tendency toward flattening of the sustentaculum tali, and medial and downward slippage of the talar head). The clarity of the CT images facilitated the surgeon's pre- and postoperative evaluation. In particular, it was easy to plan the correction of the valgus deformity, anticipate any special requirements for reinforcing the articular surfaces, and assess the results of surgery. We conclude that coronal CT scans clearly demonstrate abnormalities and help the surgeon evaluate the rheumatoid hindfoot.

Adult↗
PubMed1985

Differentiation of malignant from benign adrenal masses: predictive indices on computed tomography.

CT findings in 43 adrenal masses were analyzed to see which features correlated most significantly with malignancy. Size, contrast enhancement, and consistency emerged as important discriminators of malignant from benign adrenal masses. These three factors were further analyzed by logistic regression technique to examine the joint influence of computed tomographic (CT) features in prediction of malignancy. As a result of logistic regression analysis, a table of estimated probability of malignancy as a function of tumor size alone and another table of estimated probability as a joint function of size and contrast enhancement were developed. Given a similar patient sample and by using the data given, it would be possible to predict chances of malignancy in an adrenal mass if its CT features are known; for example, a 5-cm adrenal mass without enhancement has a 0.31 probability of malignancy; with enhancement, a 0.68 probability.

Adenoma↗
PubMed1985

Radiologist as consultant: direct contact between referring clinician and radiologist before CT examination.

The need for better direct communication between referring clinicians and radiologists has recently been emphasized. Responding to this need, a system was designed and implemented that used a radiologist as a consultant for scheduling body computed tomographic (CT) examinations. Under this system (in the "experimental" period), the referring clinician was required to consult with a body CT radiologist to schedule an examination in addition to completing a standard written radiology requisition. Before implementing this system (in the "control" period), only the written requisition was required. Ninety-five percent of referring clinicians were willing to cooperate with the new system. Benefits of the verbal consultation system included obtaining more clinical information (p less than 0.001) than was on the requisition alone (2.05 +/- 1.72 extra clinical data items), formulation of improved scanning protocols, a reduction in the number of post-CT diagnostic tests, and improved clinician-radiologist rapport. The costs of the system were mainly the nearly 5 min it took to schedule each case. It was concluded that a system that uses the radiologist as consultant and requires oral consultation between clinicians and radiologists can be implemented and has measurable benefits for patient care.

Economics, Medical↗
PubMed1985

Experimental evaluation of iosefamate meglumine and its derivatives as hepatobiliary CT contrast agents.

Iosefamate meglumine has attracted attention as a possible hepatobiliary contrast agent for CT scanning. However, its limited hepatic opacification has prevented clinical acceptance. To find a more efficient agent, the efficacy and toxicity of six derivatives of iosefamate were compared with those of the parent compound in dogs. Twenty dogs received intravenous doses ranging from 150 to 600 mg I/kg of one of these seven water-soluble, ionic, dimeric agents. Three control animals received equivalent amounts of physiologic saline. The CT densities of liver, biliary tract, kidneys, and blood were then measured for up to 3 hr. Toxicity tests of liver and kidney function were performed for up to 3 days. Among the new agents, only MI-294, a previously unreported compound, proved to be a slightly more efficient hepatic opacifier than iosefamate (0.40 vs. 0.34 H per mg I/kg, respectively). MI-294 was also the least toxic. However, transient abnormalities in at least one liver function test were observed with every agent at some dose level. One animal died with hepatic necrosis after receiving iosefamate. No renal impairment was noted in any case. MI-294 has advantages over iosefamate as a CT liver and biliary opacifier in dogs. Potential hepatotoxicity of this class of agents needs to be more fully evaluated.

Animals↗
PubMed1985

CT findings in normal and dislocating shoulders.

Computed tomographic (CT) scans of the shoulders of 10 normal individuals and six patients with a history of recent or recurrent shoulder dislocation were reviewed. In normal individuals, the surface of the glenoid was smooth and was always within 10 degrees of being perpendicular to the body of the scapula. As scans progressed from cephalad to caudad, the glenoid surface twisted and faced more anteriorly. The center of the humeral head always projected within the central one-third of the glenoid fossa. In the patients with dislocations, CT scans depicted a variety of lesions, including: bony abnormalities of the glenoid surface (fragmentation, fracture, irregularity) in three patients; abnormal glenoid-scapular angles in two; loose bodies in two; subtle subluxation, coracoid fracture, cystic humeral defect, and soft-tissue calcification in one patient each. Scans without intra-articular contrast could not demonstrate capsular or labral abnormalities. CT images are helpful in the pre- and postoperative assessment of some patients with shoulder dislocation.

Adult↗
PubMed1984

Computed tomography and conventional radiographs of the craniocervical region in rheumatoid arthritis. A comparison.

Radiographs and computed tomography (CT) scans of 12 patients with rheumatoid arthritis of the cervical spine were reviewed to determine whether CT provides additional information to that obtained from conventional radiography and tomography. Modalities were compared with respect to determination of the extent of erosion, C1-C2 subluxation, atlantoaxial impaction, and soft tissue findings. CT showed greater extent of erosion in 9 of 12 patients. In 11 patients with C1-C2 subluxation, CT and plain radiographs were both useful because it was necessary to demonstrate both sagittal and axial relationships. In the 5 patients with atlantoaxial impaction both CT and plain radiographs demonstrated the abnormal relationships between the odontoid and the foramen magnum. CT showed attenuation of the transverse ligament and the presence or absence of spinal cord compression, whereas plain radiographs did not. Nevertheless, significant new information regarding the spinal cord was obtained by CT in only 1 of the 12 patients. Computed tomography provides additional information about the rheumatoid cervical spine that is unobtainable by conventional modalities. In particular, CT demonstrates bone changes in the axial projection and facilitates evaluation of soft tissue, ligament, and spinal cord involvement. However, CT should be reserved for those instances in which plain radiographs and tomograms do not explain clinical findings.

Aged↗
PubMed1984

Abnormal intraabdominal gas collections visualized on computed tomography: a clinical and experimental study.

Abnormal intraabdominal gas collections visualized on CT scans during a 1-year period were reviewed. There were 34 collections in 29 patients. Sixty-two percent of these abnormalities were noninfectious and iatrogenic in origin, usually a direct result of procedures such as surgery, diagnostic tests, and needle or tube placement. Infections/abscesses (18%), hernias (15%), and gastrointestinal perforations (6%) produced the other abnormal gas collections. In the experimental animal study, gas collections as small as 5cc could be visualized on CT images. Collections of up to 20cc were visible for similar periods of time on both CT scans and conventional radiographs. It is concluded that most abnormally placed gas collections seen on CT are iatrogenic and that CT scans are very sensitive for the detection of such collections.

Adult↗