Search PubMed⌕ Search

Biomedical subjects

D M Paushter

Publications and source records attributed to D M Paushter.

At least 19 recordsLinked to original sources
PubMed1995

Use of contrast material for spiral CT of the abdomen: comparison of hepatic enhancement and vascular attenuation for three different contrast media at two different delay times.

OBJECTIVE: The purpose of this study was to determine the relative effects of delay time, contrast agent concentration, and contrast agent volume on hepatic enhancement and on aortic and portal vein attenuation for contrast-enhanced spiral CT of the abdomen. The effect of delay time was evaluated by comparing two different delay times for each of three IV contrast media. Three different media were tested to identify whether the effects were different with different iodine concentrations and doses or with different volumes of contrast medium. SUBJECTS AND METHODS: A total of 169 patients who underwent contrast-enhanced CT of the abdomen with spiral CT imaging were evaluated for enhancement of the liver parenchyma and for postenhancement attenuation of the aorta and portal vein. Total iodine doses of 30 g as 100 ml of iohexol 300 or 125 ml of ioversol 240 and of 40 g as 125 ml of ioversol 320 were evaluated at delay times of 45 and 60 sec and with a low-flow monophasic injection at a rate of 2 ml/sec. RESULTS: For each contrast medium tested, a 60-sec delay provided greater hepatic enhancement than did a 45-sec delay (43 vs 32 H for iohexol 300, 37 vs 28 H for ioversol 240, and 50 vs 39 H for ioversol 320; all comparisons, p < or = .0001). The aortic attenuation achieved in the abdomen after contrast medium administration was significantly greater with a 45-sec delay than with a 60-sec delay for iohexol 300 (p = .0290) but not for the other contrast media. The portal vein attenuation achieved after contrast medium administration was significantly greater with a 60-sec delay than with a 45-sec delay for all three contrast media (p = .0051). CONCLUSION: When IV contrast material was injected with a low-flow-rate monophasic bolus, a delay time of 60 sec, longer than that typically used for dynamic incremental scanning, provided greater hepatic enhancement in spiral CT. This result was significant for the three contrast media tested. Aortic attenuation was significantly greater at shorter delay times when a smaller volume of contrast material was injected. Portal vein attenuation was greater at longer delay times, suggesting that the optimal delay time may be longer than 60 sec. Further work to determine the optimal scanning window for hepatic enhancement in spiral CT by use of time-density curves is indicated.

Analysis of Variance↗
PubMed1993

Gastrointestinal radiology: current indications and referral patterns.

To determine the current indications and referral patterns for routine gastrointestinal radiology examinations, 1000 consecutive patients were prospectively analyzed. The following specialties were the largest sources of referral: general internal medicine (38%), gastroenterology (21%), and general and colorectal surgery (17%). Referrals from gastroenterologists were weighted toward areas not well evaluated by endoscopy, such as suspected small bowel disease. The major indications for upper gastrointestinal (GI) examinations were dysphagia and swallowing disorders (32%), hiatus hernia/reflux (14%), and ulcer (14%). Small bowel series were predominantly performed for inflammatory bowel disease (37%), obstruction (25%), and occult blood loss (18%). The majority of combined upper GI/small bowel studies were performed for indications primarily relating to the small bowel. Forty percent of barium enemas were performed for detection of neoplasms and polyps, with pain/irritable colon (14%) and exclusion of leak (14%) the next most common indications. Traditional indications, such as peptic ulcer disease and neoplastic disease, continue to be sources of referral for gastrointestinal radiology. However, more specialized applications, particularly in areas not well suited to endoscopy, such as swallowing disorders, inflammatory disease of the small bowel, and evaluation of surgical anastomoses, are also being commonly used. The changing indications, along with the previously documented decreased volume of gastrointestinal radiologic procedures, should be kept in mind when planning a radiology resident educational curriculum.

Digestive System↗
PubMed1993

Spiral CT of the abdomen: artifacts and potential pitfalls.

Spiral CT has been advocated as a major advancement in CT technology. Spiral CT scanning is rapid, the volume of IV contrast material can potentially be decreased, and high-quality coronal, sagittal, and three-dimensional reconstruction is possible. However, when compared with dynamic CT, because of the shorter acquisition time of spiral CT, vascular and organ enhancement on spiral CT scans is more dependent on factors that affect the delivery of contrast material into the bloodstream and on the time that scanning begins after the start of injection of contrast material. Additionally, organs other than the liver are scanned earlier than they typically are during a dynamic study, particularly the kidneys and spleen. In our experience to date, these aspects of spiral scanning have led to several difficulties in the interpretation of spiral CT scans. This essay illustrates potential pitfalls in the interpretation of spiral CT scans associated with scanning too soon after injection of contrast material.

Artifacts↗
PubMed1992

Comparison of iohexol-240 versus iohexol-300 in abdominal CT.

Forty patients without evidence of liver, kidney, or significant cardiac disease were prospectively divided into two groups of 20, receiving either iohexol-240 or iohexol-300. A contrast load of 150 ml was administered in conjunction with a rapid scanning technique at a preselected, fixed level to include liver, renal cortex, and aorta. Peak enhancement was calculated as change in Hounsfield units (HU) over baseline for each area of interest. Mean peak enhancement and standard deviation were calculated for each organ, and the difference between the means for the two contrast agents was compared using the Student's t test. Differences were not statistically significant with all p values greater than 0.05. Our results suggest iohexol-240 is preferred to iohexol-300 for body computed tomography (CT) due to its lower cost and iodine load without statistically significant change in diagnostic quality of the examination.

Evaluation Studies as Topic↗
PubMed1992

Hypoechoic renal pyramids: sonographic visualization in older children and young adults.

The frequency and degree of visualization of medullary pyramids in a normal population, aged 10-29 years, was analyzed. Hypoechoic pyramids were visualized in 42% of right kidneys in subjects aged 10-18 years and in 27% of subjects aged 19-29 years. Prominently hypoechoic pyramids, mimicking the appearance of neonatal kidneys, were seen in an additional 34% of subjects aged 10-18 years and in 16% aged 19-29 years. Prominent pyramids were present in 50% of subjects with renal cortical echogenicity (RCE) equal to liver, but also in 21% of subjects with RCE less than liver. Our study expands the age at which prominently hypoechoic medullary pyramids can be considered a normal finding. This may relate to recent improvements in ultrasound technology.

Adolescent↗
PubMed1992

Fibrotic lesions of the testicle: sonographic patterns mimicking malignancy.

All testicular sonograms performed over a 2.5-year period were retrospectively reviewed, yielding eight patients with pathologically proven lesions consisting primarily of tubular sclerosis and interstitial fibrosis. Only two patients (25%) had a palpable abnormality. A variety of sonographic patterns was found, including focal hypoechoic or hyperechoic lesions and diffuse heterogeneity of the testicular parenchyma. The clinical and sonographic findings prompted open biopsy or orchiectomy in all cases. In the same time period, nine pathologically proven testicular malignancies were evaluated sonographically and displayed either well-defined hypoechoic or diffusely heterogeneous echo patterns. All but two of these patients (78%) had palpable abnormalities. This study demonstrates a significant overlap in the sonographic appearance of benign fibrotic lesions and testicular malignancies. When careful palpation of a sonographically heterogeneous or focal hypoechoic lesion fails to reveal a mass and serum tumor markers are negative, an open biopsy with frozen section analysis should be considered rather than proceeding directly to orchiectomy. Homogeneously hyperechoic masses can be considered benign and do not require surgery.

Adult↗
PubMed1992

Doppler color imaging. Scrotum, breast, thyroid, and extremities.

DCI, when coupled with small-parts gray-scale imaging, has demonstrated great utility in the evaluation of superficial body abnormalities. This technique has rapidly become a primary method of evaluation of suspected testicular torsion, and its results are competitive with those of standard nuclear medicine examinations. DCI evaluation of male impotence, coupled with intracavernous injection of vasoactive substances, is now a leading, noninvasive technique for diagnosis of both arteriogenic and venogenic causes. DCI may provide invaluable information in the evaluation of palpable masses, particularly in the diagnosis of vascular abnormalities such as false aneurysm and arteriovenous fistula. Further studies are needed to corroborate the utility of DCI in the evaluation of focal thyroid and parathyroid abnormalities, breast carcinoma, nodal cancer, and the orbit. Because this technique is applicable to superficial, high-frequency examinations, DCI is rapidly becoming an accepted and frequently necessary part of any small-parts ultrasound study.

Color↗
PubMed1990

Comparison of magnetic resonance imaging and ultrasonography in staging early prostate cancer. Results of a multi-institutional cooperative trial.

BACKGROUND: In 1987, a cooperative study group consisting of five institutions was formed to determine the relative benefits of magnetic resonance imaging (MRI) and endorectal (transrectal) ultrasonography in evaluating patients with clinically localized prostate cancer (stage Ta or Tb). METHODS: Over a period of 15 months, 230 patients were entered into the study and evaluated with identical imaging techniques. We compared imaging results with information obtained at the time of surgery and on pathological analysis. RESULTS: MRI correctly staged 77 percent of cases of advanced disease and 57 percent of cases of localized disease; the corresponding figures for ultrasonography were 66 and 46 percent (P not significant). These figures did not vary significantly between readers; moreover, simultaneous interpretation of MRI and ultrasound scans did not improve accuracy. In terms of detecting and localizing lesions, MRI identified only 60 percent of all malignant tumors measuring more than 5 mm on pathological analysis and ultrasonography identified only 59 percent. CONCLUSIONS: The MRI and ultrasonography equipment that is currently available is not highly accurate in staging early prostate cancer, mainly because neither technique has the ability to identify microscopic spread of disease. Further evaluation with improved equipment may improve the accuracy of these techniques.

Adult↗
PubMed1990

Renal artery stenosis: evaluation with color Doppler flow imaging.

Renal artery stenosis (RAS) is the most common correctable cause of hypertension. The current study was undertaken to evaluate the usefulness of color Doppler flow imaging as a screening examination in the detection of significant RAS. Fifty-five kidneys in 30 patients were examined with aortography and color Doppler flow imaging in a double-blind fashion. The peak systolic velocity (PSV) in the renal artery, the renal-aortic ratio (RAR) (ie, the ratio of the PSV in the renal artery to the PSV in the aorta), and the renal artery resistive index were determined and compared with the percentage of stenosis as determined with angiography. Ultrasound (US) criteria used to diagnose RAS were (a) an RAR of 3.5 or greater and/or (b) a renal artery PSV of greater than 100 cm/sec. Doppler tracings were obtained in 25 (69%) of 36 kidneys with a patent single renal artery. RAR and PSV each yielded a sensitivity of 0% in the diagnosis of RAS. Doppler tracings were obtained in three (50%) of six occluded renal arteries. Accessory arteries were present in 13 (24%) of 55 kidneys, but none were visualized with color Doppler flow imaging. The authors conclude that with current technical capability, color duplex US is not an adequate screening method for the detection of RAS.

Angiography, Digital Subtraction↗
PubMed1989

CT evaluation of suspected hepatic metastases: comparison of techniques for i.v. contrast enhancement.

Although IV injection of contrast material is widely used for detection and follow-up of hepatic metastases on CT, the optimal method of contrast enhancement has not yet been defined. A prospective study was performed in 50 consecutive patients with suspected hepatic metastases. Lesion size and detectability were compared on unenhanced CT scans, scans obtained during a bolus injection of contrast material (early bolus phase), and scans obtained during a rapid infusion after the loading bolus. A total of 60 hepatic lesions were evaluated in 26 patients, 19 with histologic confirmation of metastases and seven with strong supportive evidence. The bolus phase allowed detection of 15% more lesions than did examination during the rapid-infusion phase. Lesion size varied, depending on the timing and method of contrast administration; the largest measurements were obtained during bolus injection of contrast material. In addition, bolus administration of contrast material subjectively resulted in the best lesion detection. Because the three techniques of IV contrast enhancement may produce different size measurements, sequential examinations must be tailored appropriately. Scanning during the bolus phase is technically possible with current CT equipment and is recommended as the primary CT screening examination for hepatic metastases.

Contrast Media↗
PubMed1988

Follicular aspiration: a comparison of an ultrasonic endovaginal transducer with fixed needle guide and other retrieval methods.

Ultrasonic techniques have been developed as alternatives to conventional laparoscopic aspiration for oocyte retrieval for in vitro fertilization (IVF). Given the advantages (less risk, lower cost, and greater patient acceptance) of these alternative techniques, it is appropriate to assess their efficacy compared with traditional laparoscopic retrieval. This article examines the recovery rate of oocytes and their subsequent fertilization rate with the use of an ultrasonic endovaginal transducer with fixed needle guide and compares these results with other retrieval methods. Comparisons were made between laparoscopic harvesting (n = 71, group I), ultrasonic transabdominal transvesical (n = 21, group II), and ultrasonic vaginal transducer (n = 76, group III). The data demonstrate comparable success using an ultrasonic endovaginal transducer with fixed needle guide. The authors believe this technique to be the procedure of choice for all routine oocyte retrievals during IVF treatment.

Female↗
PubMed1988

Peripheral pseudoaneurysms: evaluation with duplex US.

The prospectively generated results of 64 duplex sonographic examinations in 59 patients being evaluated for peripheral pseudoaneurysms over a 2-year period were reviewed. Subsequently, two groups of patients were identified. Group 1 (45 examinations) presented with relatively acute symptoms after arterial puncture, and group 2 (19 examinations) had undergone previous vascular surgical procedures and were usually asymptomatic. Duplex sonography demonstrated high sensitivity (94%) and specificity (97%) for the diagnosis of pseudoaneurysm in group 1. Of the 19 studies in group 2, duplex sonography allowed correct identification of pseudoaneurysms in four studies and exclusion of this entity in six examinations. The duplex sonographic findings in nine studies in this group did not allow differentiation of pseudoaneurysm from true aneurysm or oversize graft anastomosis. Duplex sonography is suggested as a primary radiologic method for evaluating possible pseudoaneurysms after arterial puncture, and it may provide valuable information and a means of postsurgical follow-up of selected patients as well.

Adult↗
PubMed1988

Breast specimen radiography: evaluation of a compression device.

The irregular shape and uneven tissue thickness of excised breast specimens makes radiographic evaluation difficult, especially when calcifications are not present. Xeroradiographs before and after compression of 20 separate excised breast specimens were compared, and 17 of the same specimens were compared after compression combined with immersion in water. Specimen compression improved visibility of the lesion on average in 88% of cases, and visibility was equal in 12%. Combined compression/immersion further improved visibility of the lesion on average in 37% of cases. More significantly, evaluation of the compressed specimen led to a change in interpretation of the radiographs in 45% of cases. Compression of the specimen in specimen radiography is recommended in all cases in which pre-biopsy localization is performed.

Biopsy↗
PubMed1988

CT of the liver: a survey of prevailing methods for administration of contrast material.

The members of the Society of Body Computed Tomography were surveyed to determine the most frequently used method of administering contrast material in CT studies of the liver. The respondents represented CT departments performing liver examinations in 22 institutions. No department relied solely on noncontrast scans. In 12 (54%) of 22 institutions, only contrast-enhanced scans were performed. The preferred dose for enhancement was 150 ml of 60% contrast material. Eight (36%) of the 22 respondents obtained images during the administration of a bolus of contrast material, whereas nine (41%) obtained images during the administration of a sustained drip infusion given after a loading bolus. Follow-up in 1987 revealed that two departments had switched to obtaining images during the administration of a bolus. The availability of CT power injectors and refinements in the rapid-scanning capabilities of CT scanners have increased the popularity of obtaining images of the liver during the administration of a bolus of contrast material. Despite this, in many departments, contrast material is still administered via drip infusion in CT studies of the liver.

Contrast Media↗