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Objective: This study was designed to determine whether significant changes have occurred in the utilization of sonography relative to more expensive cross-sectional imaging techniques in adult patients during a time of increasing reliance on managed care., Materials and Methods: Use of sonography was compared with use of CT and MR imaging of the abdomen, pelvis, and retroperitoneum in adult patients in 1993 and 1998 at an academic medical center. Clinicians who requested the greatest number of examinations in both years were surveyed to assess their perception of changes in their practice patterns during the interim., Results: Between 1993 and 1998, the use of sonography relative to the other cross-sectional imaging modalities decreased from 56% to 43% (p < or = 0.001). During the same time, CT use increased from 30% to 41% (p < or = 0.001), and MR imaging use increased from 14% to 16% (p < or = 0.001). Survey responses indicated that potential cost saving was not a major factor in physicians' decisions to use sonography rather than other cross-sectional imaging modalities., Conclusion: Sonographic utilization decreased during a 5-year period in which managed care provided an increasingly large proportion of overall reimbursement. Cost did not appear to be a major factor in selection of diagnostic tests. Differences over time in refering clinicians' perception of the relative usefulness of sonography, CT, and MR imaging may have contributed to the change in usage patterns.

Objective: Our goal was to determine if normal and abnormal pregnancies could be distinguished at smaller sac sizes with a higher frequency transvaginal transducer than with a 5-MHz transducer., Subjects and Materials: Thirty-nine patients with potentially abnormal pregnancies identified with a 5-MHz transvaginal transducer were immediately reimaged with a 9-5-MHz transducer. We compared our ability to visualize the yolk sac, embryo, and cardiac activity relative to mean sac diameter on imaging at both frequencies in women with normal and abnormal pregnancies., Results: Of the 39 pregnancies, 22 (56%) were normal or probably normal. Using the 5-MHz transducer, a yolk sac was first seen in a 6.4-mm gestational sac but was not definitively seen in 12 gestational sacs measuring 5-13 mm. Using the 9-5-MHz transducer, yolk sacs were identified in all gestational sacs measuring 4.6-13 mm, and live embryos were seen in five of eight sacs measuring 8.1-13 mm. The largest normal gestational sac without a live embryo measured 11 mm. When we compared these pregnancies with 17 (44%) abnormal pregnancies, we found that all pregnancies that had no yolk sac by the time the gestational sac measured 5.0 mm or no live embryo by 13 mm had abnormal findings on higher frequency imaging., Conclusion: The ability to visualize the yolk sac and embryo in early pregnancy is critically dependent on transvaginal transducer frequency. Threshold values and discriminatory sizes used to distinguish normal and abnormal pregnancies are smaller on higher frequency than on lower frequency imaging and, therefore, should be redetermined for specific transducer frequencies.

Diagnostic pelvic lymphadenectomies are used in both bladder and prostate carcinoma. Enhanced rapid-sequence computed tomographic (CT) scanning of the retroperitoneum and pelvis was done prospectively in patients scheduled for lymphadenectomies. The CT results were then compared to the histopathological findings in 32 patients to analyze the ability of dynamic CT to indicate whether a lymphadenectomy is needed. The comparison showed eight true positive, four false negative, 18 true negative, and two false positive. The sensitivity was 66%, specificity 90% and accuracy 81%. The diagnostic considerations of the role of CT based on these findings are illustrated and discussed.

Both sonography and fluoroscopy have been recommended for renal localization and needle guidance for percutaneous nephrostomy. The respective efficacies of both methods have been compared in a prospective study of 88 patients undergoing percutaneous nephrostomy by the catheter over guide wire technique. Fifty-five patients had initial puncture using either an A-mode (42 patients) or real time (13 patients) sonographic aspiration transducer, while 33 patients had a single plane vertical beam fluoroscopy for puncture guidance. The use of either sonographic method for the initial needle puncture significantly reduced the number of puncture attempts (p = 0.000004) and potential iatrogenic risk, eliminated the need for intravenous administration of contrast material, allowed initial safe introduction of a large caliber needle, and decreased the length of time needed to perform the procedure.

High-density renal masses are atypical lesions that represent a diagnostic dilemma for computed tomography (CT). The differential diagnosis includes mainly complicated benign cysts and malignant neoplasms. This report analyzes the CT findings in 17 cases of discrete, sharply marginated masses that initially exceeded the density of the uninvolved renal parenchyma, averaging 50 H or more. The subsequently proven pathologic entities responsible for these high attenuation values included primary malignancies in six patients, one of whom also had multiple retention cysts containing highly proteinaceous, gelatinous material; a hemorrhagic cysts with an associated desmoplastic, fibrotic reaction in one patient; and single or multiple hemorrhagic cysts in four patients. No histologic proof was obtained in six patients, three with neoplastic disease and one mentally retarded youth who underwent renal aspiration without sufficient material obtained for analysis. Two patients with presumed hemorrhagic cysts have had serial CT scans without interval change in 8-12 months. An approach to the therapeutic management of affected patients is described.

Flowing "particles" have been observed within abdominal veins using high-resolution real-time scanners. Experimental models in which fluids of different composition were infused into each other show strong echoes corresponding with visual laminations before complete admixture has occurred. Interfaces between different fluids within the physiologic range seem adequate to account for these echoes. As predicted by this observation, the laminar flow echoes are seen downstream of junction sites where blood different compositions flows together, notably at the renal and hepatic vein junctions with the inferior vena cava, but the phenomenon is not seen in arteries.

The radiographic and computed tomographic features of nontraumatic (spontaneous) hemorrhage into the renal sinus in four patients on anticoagulant therapy are described. Spontaneous renal sinus hemorrhage, a benign self-limited process related to anticoagulation, may have a lesser association with occult renal neoplasms than other types of renal bleeding. The diagnostic criterion of uncomplicated bleeding into the renal sinus is extrinsic compression of the pyelocaliceal system that proves to be completely reversible with spontaneous dissolution of clot. Often there is impaired excretion of contrast material with proximal caliectasis.

To evaluate the impact of computed tomography (CT) on therapeutic management decisions in solid tumors of the chest and abdomen, 92 examinations on 54 children with 13 histologic tumor types were analyzed. The CT impact on the management decisions was analyzed in relation to other diagnostic procedures of the same body part including sonography, chest films with tomography, abdominal/pelvic films, and excretory urography. Overall, CT provided the essential information of 47% of management decision. By confirming non-CT examination results it helped direct therapeutic decisions in 28%. No additional information was derived from CT in 20%. Technically poor studies in 5% resulted in CT errors. According to the procedural method, CT provided additional information in 42% when compared with sonography, in 38% when compared with chest films and tomography, in 41% when compared with abdominal/pelvic films, and in 27% when compared with intravenous urography. The investigation showed that CT provided information directly affecting the therapeutic management decision in a significant number of patients.

After pelvic exenteration for cancer, the gracilis muscles, skin, and subcutaneous fat from the inner aspect of both thighs may be raised as a pedicle flap and tunneled under the skin into the pelvic space to create a neovagina. We reviewed nine pelvic CT examinations in six patients to evaluate the CT appearance of this procedure and its complications. Five patients are alive and without complications. One patient died 6 months after surgery and had a small-bowel fistula to the neovagina. Normal CT findings included air in the vaginal canal in six of nine examinations, gracilis muscle atrophy in two patients who had early and late CT studies, and early separation of the anterior and posterior approximation of the flaps in one patient. Abnormal findings were seen in two patients: one had an abscess near the vaginal apex that was drained per vagina; the other had extraluminal air in the retropubic and subcutaneous fatty tissues due to a small-bowel fistula into the vagina.

Thirteen patients with surgically proven endometriosis underwent ultrasonography as part of their diagnostic evaluation. An attempt was made to assess the sonographic characteristics of endometriosis to determine if a characteristic pattern would emerge when the clinical presentations and physical findings were coupled with the ultrasonic picture. Ultrasound showed pelvic masses in all patients. Most masses appeared spherical and separate from the uterus and were cystic or predominantly cystic with scattered peripheral echoes. This retrospective study suggests a more useful role for ultrasound than previously recognized in the clinical management of patients with endometriosis.

Real-time sonography was used to examine the biliary tracts of 103 pregnant women. Common hepatic duct size, degree of right hydronephrosis, and presence of gallstones were noted. There were three important observations: (1) The top normal size of the common hepatic duct was 5 mm; (2) no correlation was found between common hepatic duct size and stage of pregnancy or degree of right hydronephrosis; and (3) gallstones were incidentally noted in 3.9% of patients.

CT scanning was performed on 29 consecutive patients with clinically localized prostatic carcinoma (stage A or B). Bipedal lymphangiography was performed in 12 cases. Histologic confirmation was obtained in 15 cases (pelvic lymphadenectomy in 12 and positive percutaneous needle biopsy in three). In these 15 proven cases, the overall accuracy of CT was 93% with one false positive and no false negatives. Lymphangiography was far less accurate (55%) with two false positives and three false negatives in 11 proven cases. The greater accuracy of CT resulted primarily from its ability to detect abnormal nodes in the pelvis, particularly hypogastric nodes, which are rarely opacified by lymphangiography. Preliminary experience suggests that CT is superior to lymphangiography in detecting early lymphatic spread from prostatic carcinoma in the pelvis. In the future, CT-guided percutaneous needle biopsy should be useful for documenting metastases in these patients.

The value of ultrasound in determining the etiology of nonopaque filling defects seen in the renal pelvis at intravenous urography is under study. The ultrasound findings in three patients with proven transitional cell carcinoma of the kidney were similar and consisted of separation of the central renal echo complex by a region of low-intensity echoes. This pattern is distinct from characteristically echogenic nonopaque renal calculi and anechoic hydronephrosis. Renal collecting system blood clots may have an echo pattern similar to collecting system tumors, but can usually be distinguished by their mobility and transitory nature. Further investigation into the specificity and sensitivity of the ultrasonic diagnosis of renal collecting system masses is underway.

Neurofibromatosis is a relatively common disorder that often involves many organ systems. One of the least understood aspects of this malady is a well documented potential for sarcomatous degeneration of neurofibromas. The inability to identify patients at risk and the lack of noninvasive screening methods for symptomatic patients often leads to late diagnosis. In six of seven subsequently proven neurofibrosarcomas, CT demonstrated low-density areas that histopathologically appeared to be due to necrosis, hemorrhage, and/or cystic degeneration. The density differences within these sarcomas were enhanced by the intravenous administration of iodinated contrast agents.

The pelvic MR examinations of 40 men without known prostatic disease were reviewed retrospectively. Axial long TR/long TE images were evaluated with respect to prostatic zonal size and signal intensity. Findings were correlated with each patient's age (17-74 years). The central region of the prostate and the peripheral zone enlarged with age; the central gland increased in size by an average of 175% between the second and eighth decades and the peripheral zone increased by an average of 67%. The anterior fibromuscular stroma decreased with increasing age (from an average anteroposterior thickness of 1.2 cm in the second decade to 0.4 cm in the eighth decade) and also became thinner as a function of increasing gland size. The periprostatic venous plexus became less prominent as a function of increasing age, decreasing from 2.5 to 1.5 mm in average maximal diameter, but this venous caliber was not significantly correlated with gland size. The conspicuity of the peripheral zone with respect to the central gland was improved, both as a function of increasing age and increasing gland size, and conspicuity was greatest on long TR/long TE images because of excellent contrast resolution. We conclude that in older age groups, the zonal anatomy of the prostate is more clearly defined than in young patients, both because of morphologic changes in prostate structure and because of physiologic changes resulting in differing zonal MR signal intensities.

CT staging was performed in 49 consecutive patients with known carcinoma of the bladder. The overall accuracy of CT staging in 25 patients with surgically confirmed disease stage was 64%. Most diagnostic errors in this series were related to the determination of perivesical fat involvement by tumor. The overall accuracy of CT in predicting lymph node metastasis was 92%. The sensitivity was 60% and the specificity ws 100%. Because of the current management of bladder carcinoma, the major role of CT is in the evaluation of lymph nodes for metastatic disease. Since CT cannot detect metastasis to nonenlarged lymph nodes, it has only a limited role in the staging of bladder carcinoma at this time.