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Biomedical subjects

N Susman

Publications and source records attributed to N Susman.

At least 19 recordsLinked to original sources
PubMed1992

Lateral dual-energy radiography: artifact error from rib and pelvic bone.

A lateral projection of the lumbar spine with dual-energy radiography (DER) may be a more sensitive tool for the detection of vertebral demineralization than the standard anterior-posterior (AP) DER measurement. The lateral view allows measurement of the vertebral body and selective measurement of the central trabecular compartment, excluding the majority of the cortical envelope and posterior vertebral elements. The lateral DER typically contains L2-4 in the region of interest. The present study was designed to investigate the frequency and bone mineral content (BMC) contribution of rib to the L2 vertebral body BMC measurement in a lateral view DER scan. In addition, the frequency of pelvic overlap of L4 was evaluated. All patients were scanned in the supine position. Abdominal CT images of L2 were examined in 20 women aged 28-82 years to determine the frequency of rib and pelvic interference. QCT images of L2 also were examined in an additional 35 women aged 20-82 years to further investigate the frequency of rib overlap and to calculate the potential contribution of rib superimposition to the L2 BMC in a lateral projection. Pelvic overlap of L4 occurred in 15% of the 20 cases reviewed. Rib overlapped the L2 vertebral body in 100% of the L2 images. The expected contribution of rib BMC to L2 BMC in a lateral DER scan was 10.4% on average. There was no relationship between the percentage of rib BMC contribution and age and relatively poor correlations between rib BMC and that of either the vertebral body or the central trabecular compartment of L2. We conclude that supine positioning allows routine inclusion of L3 and L4 in a lateral lumbar scan. Results also suggest that L2 should be excluded from DER scans on patients scanned in either the lateral decubitus or supine position.

Adult↗
PubMed1990

Opacification of ascitic fluid on delayed contrast computed tomography scans.

Ascitic fluid opacification on delayed intravenous contrast computed tomography scans was observed in eight consecutive patients imaged. This apparently common phenomenon may alter both the sensitivity and the specificity of ascitic fluid detection. It may also serve as a diagnostic aid by making nonascitic intra-abdominal fluid collections (ie, pseudocyst and cystic tumor) more apparent.

Aged↗
PubMed1990

Dual energy radiography versus quantitative computer tomography for the diagnosis of osteoporosis.

In this study we compared dual energy radiography (DER), a new, highly precise x-ray densitometric technique recently devised for measurements of vertebral mineral density and quantitative computer tomography (QCT), a densitometric technique that selectively measures the trabecular compartment of the vertebra. DER and QCT measurements were obtained in 56 healthy (H) and 48 fractured osteoporotic (OP) women using a Hologic QDR 1000 bone densitometer and a GE 9800 scanner, respectively. DER was significantly correlated with QCT in both the H (r = 0.75; P less than 0.0001) and the OP subjects (r = 0.58; P less than 0.0001). DER decreased significantly with age in the H (P less than 0.05), but not in the OP women, whereas QCT was related to age in both the H (P less than 0.0001) and the OP subjects (P less than 0.01). The rate of bone loss with age was also higher with QCT than with DER in both normal and osteoporotic women. The difference in bone density between the H and the OP subjects was larger (P less than 0.05) with QCT than with DER. Receiver operating characteristic analysis revealed that QCT was a better predictor of vertebral fractures than DER. A larger percentage of OP subjects were 2 SD or more below the normal predicted value with QCT (41%) than with DER (29%). Furthermore, the slopes of the regressions of bone density with age for normal and osteoporotic women were significantly different (P less than 0.05) with QCT but not with DER. These findings are consistent with a disproportionate loss of trabecular bone with age in osteoporosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1990

Lateral dual energy radiography: a new method for measuring vertebral bone density: a preliminary study.

Dual energy radiography (DER) is a new technique for non-invasive measurement of vertebral bone mineral density, which because of its high precision (1%), is particularly suitable for prospective analyses of time-related changes in bone mass. However, we recently found that DER is less sensitive to demineralization of trabecular bone than quantitative computed tomography (QCT). Since the compact bone of the posterior vertebral elements are included in the standard anterior-posterior DER (APDER), but not in QCT measurements, changes in trabecular bone mass attending the early phases of the osteoporotic process go undetected with the APDER technique due to the preponderance of cortical mass. Lateral-view DER (LDER), however, would minimize the contribution of vertebral compact bone as well as intra-abdominal calcifications to the trabecular component. To determine the in vivo short-term precision of the LDER method, we obtained three measurements in 18 healthy women, aged 23 to 76, during a four-week period. In addition, both APDER and LDER measurements were obtained in 53 healthy women, aged 23 to 80. The coefficient of variation for LDER was 2.8%. LDER density values accounted for a higher percentage of the variance of bone mass measurements with age (47%) than APDER (23%). Moreover, LDER declined significantly with age in both premenopausal (r = -0.42, p less than 0.05) and post-menopausal women (r = -0.50, p less than 0.005), whereas the age-related changes in APDER values failed to reach statistical significance in either group. The rate of bone loss with age in the premenopausal group was 0.45% per year with LDER, and 0.10% per year with APDER. Postmenopausal women showed a 0.78% loss of bone mass per year with LDER and 0.47% per year with APDER. The correlation between APDER and LDER was significant (r = 0.78, p less than 0.01). The accumulated data indicate that LDER may be a more appropriate technique than APDER for detecting the initial loss of vertebral trabecular bone that characterizes early subclinical osteoporotic syndrome.

Adult↗
PubMed1989

The gastric air-fluid sign: aid in CT assessment of gastric wall thickening.

The differentiation of apparent gastric wall thickening due to incomplete gastric distention from true pathologic wall thickening can be difficult on computed tomographic (CT) scanning. We have observed a transition in gastric wall thickening that is often present at or slightly above the gastric air-fluid or air-contrast level. The apparently thickened gastric wall in the dependent portion of the stomach undergoes an abrupt change to normal thickness at or above the air-fluid level. Review of CT scans in 259 patients without known or suspected gastric pathologic conditions revealed this finding, termed the "gastric air-fluid sign," in 57 patients (22%). While not considered diagnostic, the presence of this sign may allow for a greater degree of confidence in the CT assessment of gastric wall thickening in an appropriate clinical setting.

Contrast Media↗
PubMed1988

Adhesion-related variceal hemorrhage following sclerosis of esophageal varices.

A 78-year-old woman with portal hypertension had recurrent episodes of lower gastrointestinal hemorrhage two months after bleeding esophageal varices had been successfully treated with endoscopic injection sclerosis. Labeled red blood cell scans and mesenteric angiographic examination allowed a preoperative diagnosis of adhesion-related varices as the cause of bleeding. The problem was successfully treated by dividing the adhesion and resecting the involved small intestine.

Aged↗
PubMed1988

Dual energy radiography (DER): a preliminary comparative study.

Dual energy radiography (DER) has been recently proposed as a new technique for the non invasive measurement of vertebral mineral density. This preliminary study was undertaken to assess the short-term precision of DER and to compare DER to dual photon absorptiometry (DPA) measurements. Three DER measurements were obtained in 19 healthy volunteers (mean age 34.7 +/- 9.3 years) over a 3 week period. In addition, both DER and DPA measurements were obtained in 52 women (mean age 54.3 +/- 12.5 years). The coefficient of variation for the DER measurements was 1.00%. A highly significant correlation (r = 0.94; p less than 0.0001) was found between DPA and DER. Using this curve a conversion factor of -6.8% was calculated to convert DER to DPA values. Both DER and DPA were significantly and similarly correlated with age (r = -0.43, p less than 0.005; r = -0.38, p less than 0.05, respectively). The rates of bone loss, 0.66% per year for DER and 0.57% per year for DPA, were also similar with the two techniques. From these data, it is concluded that DER is a precise new method for vertebral bone mass measurements.

Adult↗
PubMed1987

Single and dual energy tomographic analysis of spinal trabecular bone: a comparative study in normal and osteoporotic women.

To investigate the effects of age on rates of bone loss and the relationship between amount of trabecular bone and clinical severity of osteoporosis, trabecular mineral density of the lumbar spine (VMD) was measured in 55 osteoporotic women and 133 healthy women with both single energy (SE) and dual energy (DE) quantitative computed tomography (QCT). The amount of marrow fat was indirectly estimated by the difference (delta) between DE and SE VMD values. The rate of bone loss in the normal women was 1.14%/yr with SE and 1.03%/yr with DE QCT. Osteoporotic patients had a VMD decline of 1.62%/yr with SE and 1.17%/yr with DE QCT. Osteoporotic patients had significantly lower (P less than 0.0001) mean SE and DE VMD at any age, but VMD was not significantly different among groups characterized by different number of fractures or different radiographic severity of fractures. The threshold values of VMD below which the risk of having fractures was increased were 99.8 and 118.7 mg/cm3, respectively, for SE and DE QCT. Dispersion around the mean, overlap between osteoporotic and healthy women, and the incidence of asymptomatic osteoporosis were greater with DE than SE QCT. Osteoporotic women had higher delta values (P less than 0.05) compared to normal women, but delta did not correlate with clinical severity of osteoporosis. The results indicate that factors in addition to the amount of spinal trabecular bone determine the number and severity of fractures in osteoporotic women; DE QCT reduce the VMD underestimation due to intravertebral fat content, but not the overlap between osteoporotic and normal women; and further anatomical studies of osteoporotic vertebrae are necessary to investigate the effect of age on intravertebral fat.

Adult↗
PubMed1981

CT findings in thoracic aortic dissection.

Computed tomography (CT) findings in 11 cases of aortic dissection were correlated with aortographic, surgical, or postmortem findings. In another two patients, the CT findings were considered diagnostic of aortic dissection but no further workup was performed. All the CT examinations were made before and after bolus injection of contrast. Many of the familiar angiographic signs were appreciated on CT, such as a thickened aortic wall, septum between two opacifying lumens, differential time density between the two lumens, and compression of the true lumen. No false-positive or false-negative studies were encountered. This experience suggests that CT is a reliable, noninvasive method for the diagnosis of aortic dissection.

Aged↗
PubMed1980

An improved snare system for the nonsurgical retrieval of intravascular foreign bodies.

We have modified a snare technique originally described for transcolonoscopic removal of colonic polyps for the retrieval of intravascular foreign bodies. The key difference from other snare techniques is the employment of a wire snare with a crimp in its midportion that enables the formation of a loop in a plane perpendicular to the axial direction of the guiding catheter. With this technique we have quickly removed a variety of objects from the right heart and pulmonary arteries in four patients.

Blood Vessels↗
PubMed1980

Lung carcinoma associated with bullous lung disease in young men.

Over a 6 year period, three cases of pulmonary carcinoma in young men with severe bullous lung disease were seen at Washington University Medical Center. The patients did not have a long cigarette-smoking exposure. It would seem that patients with severe bullous lung disease are at a higher risk for the development of pulmonary neoplasm than the general population. Physicians should be aware of this association to expedite diagnosis and therapy.

Adult↗
PubMed1978

Radiographic characteristics of colonic "mucosal bridges": sequelae of inflammatory bowel disease.

Colonic mucosal bridges are a relatively unusual entity occurring in patients with inflammatory disease of the colon. The authors describe two cases in which the pattern of multiple long, linear band-like defects may be easily misinterpreted as thickened mucosal folds, mucous strands, or foreign matter. The possibility of mucosal bridges should be considered if this radiographic pattern is demonstrated, and the patient's history is compatible with their formation.

Adult↗
PubMed1978

Alveolar-capillary oxygen disequilibrium in hepatic cirrhosis.

Hypoxemia is a frequent occurrence in patients with severe hepatic disease. Multiple mechanisms have been implicated in the production of such hypoxemia. The case of a 35-year-old man with cyanosis, clubbing, and cirrhosis is presented. Physiologic data from this patient revealed normal pulmonary function, except for a low diffusing capacity and a 28 percent shunt while the patient was breathing 100 percent oxygen. A perfusion scan with radioactive 99mtechnetium-labelled macroaggregated albumin revealed 67 percent of the labelled macroaggregated albumin in the systemic circulation. Post-mortem examination demonstrated normal pulmonary parenchyma, markedly dilated intraparenchymal capillaries and arterioles, subpleural angiomata, and cirrhosis. No anatomic arteriovenous connections were demonstrated before or after death. We conclude that the arterial hypoxemia of some patients with hepatic cirrhosis results from dilated gas-exchanging blood vessels. These widened vessels prevent end pulmonary capillary oxygen tension from reaching equilibrium with alveolar gas, perhaps because of the widened distance for diffusion.

Adult↗
PubMedDate not supplied

The extrapleural fat sign: CT characteristics.

Three cases of medially displaced extrapleural fat are presented. In these cases displacement is secondary to tumor, thoracic wall edema, and hematoma. When significantly displaced, and especially when distorted, the extrapleural fat may present a confusing CT picture. The recognition of this finding may aid in establishing differential diagnosis and staging.

Adenocarcinoma↗