Biomedical subjects
Publications and source records attributed to D M Warshauer.
A case of haemangioma of the oesophagus is presented. The computed tomographic findings of an intramural mass with marked enhancement following intravenous contrast enable the diagnosis to be suggested pre-operatively.
PURPOSE: To determine the effect of glucagon and orally administered contrast material on hepatic enhancement and metastatic lesion conspicuity on computed tomographic (CT) scans. MATERIALS AND METHODS: Nine patients with a history of hepatic metastasis underwent two CT examinations with intravenously administered contrast material. Each patient was given orally administered CT contrast material for the first examination. No oral contrast material was given in the second examination. Five patients underwent the initial CT with intravenous administration of 1 mg of glucagon; the second examination was performed without glucagon. Four patients were administered glucagon before the second examination, but no glucagon was administered before the first. Attenuation in the liver, portal vein, and aorta was measured by observers blinded to whether the patient had been given glucagon. Lesion conspicuity was rated on a continuous scale. RESULTS: Greater mean hepatic enhancement was noted on scans of patients in whom oral contrast material was administered (mean, 52 HU) versus those in whom no oral contrast material was administered (mean, 47 HU; P = .019). Glucagon was not associated with greater hepatic enhancement. Neither oral contrast material nor glucagon had a significant effect on lesion conspicuity. CONCLUSION: Oral CT contrast material is associated with a small increase in hepatic enhancement that does not appear to be clinically important. Glucagon does not appear to affect hepatic enhancement or lesion conspicuity in humans.
The purpose of this paper was to compare manganese-DPDP (Mn-DPDP) and gadolinium chelate (Gd-DTPA) contrast agents for enhancement of the normal pancreas. A total of 14 patients with focal liver disease underwent Mn-DPDP- and Gd-DTPA-enhanced 1.5 T MR examinations using spoiled gradient-echo (FLASH) technique at two separate times. Contrast agents were injected according to the currently recommended practices; Gd-DTPA was injected as a rapid bolus injection in a dosage of 0.1 mmol/kg, and Mn-DPDP was injected as a slow IV injection in a dosage of 5 mumol/kg. Quantitative region of interest measurements were made in 11 patients, and percent contrast enhancement of the pancreas and pancreas-fat signal-to-noise ratios (SNR) were determined for each agent. Images were also evaluated qualitatively by consensus reading of two investigators and overall scan quality was rated on a scale from 1 (poor) to 4 (very good). Enhancement of the pancreas immediately post Gd-DTPA was significantly higher than 15 min post Mn-DPDP (73.3 vs 36.3%; p = 0.003). On postcontrast images the pancreas-fat SNR measurements were 7.7 (i.e., pancreas higher in signal than fat) and -6.1 for Gd-DTPA and Mn-DPDP, respectively, which was significantly different (p < 0.001). Image quality was rated as 3.1 and 2.5 for Gd-DTPA- and Mn-DPDP-enhanced images, respectively. The normal pancreas enhances significantly more with Gd-DTPA than with Mn-DPDP administered under the conditions of this study. Overall image quality is also greater on the Gd-DTPA-enhanced images.
Pneumatosis intestinalis (PI) is characterized by subserosal or submucosal gas-filled cysts of the gastrointestinal tract. The course may be benign or may lead to the need for urgent surgery. Knowledge of the differential diagnosis, course, and treatment modalities are key in providing optimal care to patients who present with this entity. In this article, two cases of "benign" pneumatosis seen at our institution over a one-month period are presented, along with a retrospective review of the English literature from January 1985 to March 1995. Incidence, symptoms, gross and microscopic appearance, radiographic appearance, etiology, differential diagnosis and therapy are reviewed.
RATIONALE AND OBJECTIVES: To study the practice of obtaining serum creatinine before administering intravenous iodinated contrast medium and the costs associated with this practice. MATERIALS AND METHODS: In June 1993, a questionnaire was sent to 217 physicians who are members of the Society of Uroradiology or the Society of Computed Body Tomography/Magnetic Resonance. There were 149 respondents who completed a total of 70 questionnaires, providing a response rate of 69% (149/217). RESULTS: The percentage of institutions that always require a serum creatinine before administering intravenous contrast medium for excretory urography, body computed tomography, and head computed tomography was 13%, 20%, and 14%, respectively. In institutions where routine serum creatinine is not required, approximately 60% request a serum creatinine in either insulin-dependent or juvenile type 1 diabetes. The mean maximal acceptable time between the serum creatinine value and contrast administration is 29 days. It takes a mean of 69 minutes to get the results of a stat serum creatinine and costs a mean of 15 dollars for the test. In patients with no risk factors, the mean for the highest serum creatinine value at which respondents still gave contrast was 2.1 mg/dL; in patients with risk factors, the mean was 1.9 mg/dL. There was no correlation between the use of serum creatinine and the number of studies performed in the institution or the type of contrast used. CONCLUSIONS: The practice of requiring a pretest serum creatinine and its interpretation regarding the use of contrast media are quite variable. In view of this disparity in opinion, development and acceptance of a list of patients who are at increased risk for contrast-induced nephropathy may be desirable.
PURPOSE: To describe the computed tomographic (CT) appearance of nodular hepatosplenic sarcoidosis and its association with stage with chest radiography and clinical status. MATERIALS AND METHODS: Thirty-two patients (21 women, 11 men; aged 25-68 years) with nodular hepatosplenic sarcoidosis were evaluated. CT findings were described along with chest radiographic stage, clinical status, and level of angiotensin-converting enzyme (ACE). RESULTS: Nodules were small, multiple, and of low attenuation. Organomegaly was common. Abdominal adenopathy was present in 76% of the patients. Chest radiographs were normal in 25%; 61% had stage 1 or 2 radiographs. Abdominal or systemic symptoms were present in 66%. ACE level was elevated in 10 (91%) of 11 patients tested. No change in chest radiographic stage was noted in 74% of patients with follow-up radiographs. CONCLUSION: Nodular hepatosplenic sarcoidosis is associated with organomegaly, adenopathy, and symptoms. Nodules were not associated with advanced lung disease and did not herald a change in chest radiographic stage. An elevated ACE level may be helpful in diagnosis.
PURPOSE: To investigate the effect of glucagon on the timing and degree of hepatic enhancement at computed tomography. MATERIALS AND METHODS: Each of 11 dogs underwent injection of contrast material at two uniphasic rates (0.5 mL/sec and 1.5 mL/sec) with without previous intravenous administration of 0.5 mg of glucagon. Scans were obtained at a single intrahepatic level every 3.5 seconds for 120-160 seconds. Attenuation values in the liver, aorta, portal vein, and inferior vena cava (IVC) were measured. RESULTS: Glucagon administration was associated with greater hepatic enhancement throughout the study: Peak hepatic enhancement was greater at contrast injection rates of 0.5 mL/sec (P = .021) and 1.5 mL/sec (P = .0001). Peak hepatic enhancement also occurred earlier during the glucagon runs. Portal vein enhancement was greater during the glucagon runs at an injection rate of 1.5 mL/sec (P = .032). IVC enhancement was greater during the nonglucagon runs at 0.5 mL/sec (P = .013) and at 1.5 mL/sec (P = .005). CONCLUSION: Intravenous administration of glucagon before contrast material injection produces greater and more rapid hepatic enhancement in a canine model.
Fourteen patients underwent magnetic resonance imaging (MRI) examination (16 studies) and clinical evaluation concurrently. MRI studies included gadolinium enhancement and TI-weighted fat-suppressed spin echo. Separate investigators determined the severity of disease on MR images and on clinical evaluation in a blinded fashion. MRI studies were evaluated for percentage of mural contrast enhancement, wall thickness, and length of diseased bowel. An MR product was generated using these parameters. Clinical evaluation used the Crohn's Disease Activity Index (CDAI) and modified Index of the International Organization for the Study of Inflammatory Bowel Disease (IOIBD). Linear correlation was found between the MR product and clinical indexes of disease activity. The correlation between MR product and the modified IOIBD index was statistically significant (R(2) = 0.633, p = 0.0012). The correlation of MR product and CDAI was less close (R(2) = 0.274, p = 0.0373). Among individual MR parameters, length of diseased bowel showed the greatest correlation with CDAI (R(2) = 0.537, p = 0.012). Percentage contrast enhancement and bowel wall thickness showed significant correlation to the modified IOIBD index (R(2) = 0.739, p = 0.021) but not to the CDAI (R(2) = 0.004, p = 0.825). The results of this study show that the product of mural contrast enhancement, wall thickness, and length of diseased bowel correlated with clinical indexes of disease activity in Crohn's disease. Our findings suggest that MRI may be useful in evaluating the severity of Crohn's disease and may provide information complementary to clinical evaluation.
An ergonomically simple prototype workstation with two 900 x 1,100-pixel monitors capable of displaying eight full-resolution computed tomography (CT) images in 0.2 seconds, was compared with film for interpretation of computed tomographic images of the chest and abdomen. The hardware platform for this workstation cost less than $11,500 in 1993. A repeated-measures experiment was used to generate average interpretation times of 6.17 minutes for the workstation and 6.03 minutes for the film, including loading and unloading films, with three of the four subjects averaging about a minute longer for each workstation interpretation. All dictated reports were of clinically acceptable accuracy. All radiologists stated that workstations based on this design would be an acceptable clinical tool. However, observation suggested human working-memory strain among infrequent CT readers that could indicate the need for additional training. These data suggest that low-cost workstations can have practical application in interpretation of digital medical images such as CT, with the possibility of small increases in interpretation time.
PURPOSE: To estimate the prevalence of abdominal computed tomographic (CT) findings in sarcoidosis and to correlate these findings with those at chest radiography, clinical status, and level of angiotensin converting enzyme (ACE). MATERIALS AND METHODS: Abdominal CT examinations in 59 patients with sarcoidosis were evaluated for adenopathy, liver and spleen size, and discrete lesions within the liver or spleen. RESULTS: Extensive adenopathy was seen in 10% of patients. Marked hepatic and splenic enlargement was seen in 8% and 6%, respectively. Nodules were seen in the spleen in eight (15%) patients and in the liver in three (5%). Although liver size, spleen size, and adenopathy were directly related (P < .0001), the presence of nodules was not strongly related to organ size. Abdominal CT findings were related to clinical status and elevated ACE levels but not to chest radiographic stage. CONCLUSION: Marked abdominal CT findings are uncommon in sarcoidosis and correlate with disease activity but not chest radiographic stage.
A prototype single-screen workstation with a 2,048 x 2,560-pixel high-brightness monitor, 0.11-second image display time, and simple ergonomic design was compared to a conventional horizontal film alternator in diagnostic interpretation of chest computed tomography (CT) studies. Four radiologists used either the workstation or film alternator in interpretation of studies obtained in 10 patients. A counterbalanced within-subject repeated measures experimental design was used. Response times were analyzed for both methods of interpretation. Grades of excellent, acceptable, and unacceptable were assigned by a blinded "grader" to reports of the radiologists. The average time needed for an interpretation at the workstation was 5.65 minutes. No interpretations were graded unacceptable. Retrospective power analysis showed that 16 observers rather than four would have been required to show that use of the workstation was faster than the alternator. With this 95% confidence interval, the workstation interpretation time is clinically equivalent to that with the alternator. These data show that this type of workstation has practical application in interpretation of CT, magnetic resonance imaging, and ultrasound studies.
The computed tomographic (CT) findings of a right and left paraduodenal hernia are described. In the right paraduodenal hernia the major findings consist of encapsulation of small bowel loops in the right mid-abdomen with looping of arterial and venous jejunal branches behind the superior mesenteric artery. The findings of the left paraduodenal hernia are less specific and involve encapsulation of bowel loops at or above the level of the ligament of Treitz with intermittent dilatation.
Mucoceles of the appendix are a rare group of lesions thought to occur as a sequelae of luminal obstruction as well as certain benign and malignant neoplasms of the appendix. Early, preoperative diagnosis is rare. We report a case of an appendiceal mucocele in which the diagnosis was suggested by computed tomographic imaging and colonoscopy, and confirmed at surgery. Radiologic, endoscopic, and pathologic correlations of this rare entity are discussed.
Natural dissemination of viral respiratory illness to susceptible men may occur with surprising difficulty. This was especially evident during a 1977 outbreak of adenovirus type 21 (Ad-21) at McMurdo Station, a US research base in Antarctica. The unique circumstances at McMurdo allowed 125 men from the US to join and intermingle with 75 men who had wintered for 6 months in complete isolation. For an additional 5-week (September 2 to October 4, 1977) isolation period, respiratory illness etiology and transmission were monitored in the combined population. A total of 89% of the population was susceptible (neutralizing antibody titer, less than 1:3) to Ad-21 but only 15.0% were infected. Illness spread very slowly (1.5 cases/100 persons/week) with no epidemic peak and was much less severe than Ad-21 outbreaks in other settings. The incidence of infection (17.3%) and illness (9.6%) was low even in men who had wintered over, with values very similar to those of the newcomers (13.9% and 8.9%, respectively). Thus, despite a harsh environment and frequent prolonged gatherings of susceptible personnel, even a respiratory virus type with known epidemic potential was surprisingly difficult to transmit.
An unusual case of intrahepatic hepatic artery aneurysm (IHAA) is presented, in which the diagnosis was initially suspected on computed tomography (CT) and confirmed on color-flow Doppler ultrasound (US). The literature regarding this entity, as well as the utility of color-flow Doppler US in this setting are discussed.
Diverticula of the female urethra can be difficult to diagnose. Invasive contrast studies (voiding cystourethrography or double-balloon urethrography) or urethroscopy are frequently required for definitive diagnosis. Although transabdominal sonography has been able to visualize large diverticula, this technique has not proved useful in routine screening. In this study, we examined the use of higher frequency (5 MHz) near-focus endovaginal or transperineal sonography for the diagnosis of urethral diverticula. Five patients with radiographically proved (three with double-balloon urethrography and two with voiding cystourethrography) urethral diverticula were examined with endovaginal (two cases) or transperineal (four cases) sonography. In all five cases, sonography showed the diverticula previously demonstrated on the contrast study. The spatial relationship of the diverticula to the urethra, an important consideration at surgery, was shown more clearly by sonography than by contrast radiography. These findings suggest that sonography may be useful as a noninvasive screening technique for urethral diverticula.
Supplements consisting primarily of dietary fibers are marketed as aids to weight reduction. Of uncertain efficacy, they have generally been regarded as safe when used according to directions. We report two cases of acute esophageal obstruction by a guar gum product in patients with preexisting esophageal abnormalities and review similar reports from other centers.
It is commonly believed that living in polar isolation causes high susceptibility to respiratory illness. At McMurdo Station, a US research base in Antarctica, we tested this belief by comparing, over 36 days (August 31-October 5, 1976), the incidence and severity of respiratory illness in 64 men finishing six months isolation and in 136 men just arrived from the United States. The colds in the two intermingled populations were essentially equivalent. Forty-three per cent of the newcomers and 39% of the wintering group reported colds; symptoms and duration were nearly identical between the two populations. Movement of the colds was slow. The newcomers brought in 31 colds; subsequently, only 52 evenly spaced illnesses arose. Incidence of respiratory illness was twice higher in the smaller living units than in the spacious main dormitory. Two nontypable rhinoviruses, McMurdo 4 and McMurdo 88, were brought in by the new population and were the only viruses isolated. Only McMurdo 88 spread, although more than 65% of the men were antibody-free (less than 1:3) to either agent. McMurdo 88 caused an estimated 60% of antarctic-contracted colds. In brief, this isolated polar group was not especially susceptible to respiratory illness, and virus movement through the group was deliberate.