Positional variation in the Whitaker test

PURPOSE

To describe positional variation in the outcome of the Whitaker test.

MATERIALS AND METHODS

The authors retrospectively reviewed the cases of six patients in whom the pressure gradient during Whitaker testing varied by at least 10 cm of water and changed from normal ( < or = 13 cm of water) to abnormal ( > 13 cm of water) when patients were placed in different positions.

RESULTS

Four patients had obstruction only in nonstandard positions. All had intermittent symptoms, and three had ureteral kinks at fluoroscopy. Two patients with ileal conduits had abnormal results in the standard position but normal results at repositioning related to compression of the conduits (seen as conduit distention at fluoroscopy). All six had undergone urinary tract surgery. Gradient differences with positional change ranged from 10 to > 38 cm of water.

CONCLUSIONS

Whitaker testing in different positions may help identify intermittent obstructions that might otherwise go undetected or prevent inappropriate diagnosis of obstruction. Intermittent or unexplained symptoms, tortuous ureters, malpositioned kidneys, or previous surgery are indications for provocative positional testing.

Feasibility of MR diffusion studies in the kidney

Renal apparent diffusion coefficients (ADCs) were anisotropic within and significantly different between cortex and medulla using a relatively motion-insensitive one-dimensional technique in 20 volunteers. ADC values ranged from 1.79 +/- .39 to 2.95 +/- .58 (x 10(-3)mm2/sec), relatively high but similar to other reports. Further investigation may help clarify this data, and determine whether the findings result from diffusion properties (and/or radially oriented parenchymal architecture), or artifacts due to factors such as bulk motion.

Small echogenic renal masses: how often is computed tomography used to confirm the sonographic suspicion of angiomyolipoma?

OBJECTIVES

Although renal angiomyolipoma (AML) has a typical ultrasound appearance, many authorities suggest that a computed tomography (CT) scan be obtained to confirm the diagnosis because small echogenic renal cell carcinomas can simulate AML. Our study evaluates the actual follow-up in such patients and factors that may affect whether CT confirmation is recommended or obtained.

METHODS

From 1986 through 1992, 36 patients had an ultrasound diagnosis of probable renal AML (well-circumscribed, homogenously echogenic mass). In each case the patient's age, symptoms, ultrasound results and recommendations, and imaging follow-up were recorded.

RESULTS

CT confirmation of the sonographic diagnosis was recommended in only 11 of 36 (31%) patients. Only 7 of these 11 patients actually underwent CT, 5 of whom had the diagnosis confirmed by CT detection of intratumoral fat. Ten of 23 patients (43%) over 50 years of age had CT recommended, whereas only 1 of 13 (8%) patients under age 50 years did (P < 0.05). CT confirmation was recommended for 5 of 13 (38%) lesions greater than 10 mm and for 6 of 23 (26%) smaller masses. None of the 9 patients under age 50 years with small masses (less than 10 mm) had CT recommended.

CONCLUSIONS

Although many authorities recommend CT to confirm the sonographic diagnosis of renal AML, this algorithm is rarely followed in everyday clinical practice, especially in patients under age 50 years with masses less than 10 mm.

Hepatic artery resistance before and after standard meal in subjects with diseased and healthy livers

PURPOSE

To assess fasting and postprandial resistive index (RI) in subjects with healthy and diseased livers.

MATERIALS AND METHODS

Subjects with healthy (n = 10) and diseased (n = 33) livers underwent fasting and postprandial Doppler ultrasonography of the hepatic artery. Findings were compared with parameters for liver disease and Child class A-C and Child score of 5-15.

RESULTS

The mean postprandial RI increase in healthy subjects was 42% (all, > or = 20%) and in patients with liver disease was 7% (six, > or = 20%). Patients with class A disease (n = 12) had a significantly greater increase in post-prandial RI (13%) than those with class B or C disease (3%) (P < .05). All patients with class C disease (n = 9) had an increased postprandial RI of less than 10%. The 13 patients with at least 10% increase in postprandial RI had less severe liver disease (Child score, 6.1 +/- 1.3 [standard deviation]) than the 20 patients with less than 10% increase (Child score, 8.4 +/- 1.7) (P < .01).

CONCLUSION

A normal marked increase in postprandial RI is generally not seen in patients with severe liver disease.

Engineered anti-CD38 monoclonal antibodies for immunotherapy of multiple myeloma

Multiple myeloma is a malignancy of plasma cells for which there is no effective treatment. To develop an immunotherapeutic agent, we have raised a high affinity mAb (AT13/5) against CD38, one of the few well-characterized surface Ags present on myeloma cells. Since murine monoclonals have many disadvantages as human therapeutics, we prepared two engineered forms of the Ab: a CDR-grafted humanized IgG1 and a chimeric FabFc2 (mouse Fab cross-linked to two human gamma 1 Fc). To retain affinity in the humanized Ab, a number of changes were required to the human framework regions of the heavy chain. In particular, through systematic mutagenesis and computer modeling, we identified a critical interaction between the side chains of residues 29 and 78, which may be important for the humanization of other Abs. The properties of the humanized IgG1 and FabFc2 constructs were compared in a series of in vitro tests. Both constructs efficiently directed Ab-dependent cellular cytotoxicity against CD38-positive cell lines, but C was activated only poorly. Neither construct caused down-modulation of CD38, nor did they affect the NADase activity of CD38. Despite their differing structures, both Abs showed similar activity in most assays, although the humanized IgG1 was more potent at inducing monocyte cytotoxicity. These data represent the first direct comparison of CDR-grafted and chimeric FabFc2 forms of the same Ab, and offer no support for the perceived advantages of the FabFc2. These Abs show promise for therapy of multiple myeloma and other diseases involving CD38-positive cells.

Engineered anti-CD38 monoclonal antibodies for immunotherapy of multiple myeloma

Multiple myeloma is a malignancy of plasma cells for which there is no effective treatment. To develop an immunotherapeutic agent, we have raised a high affinity mAb (AT13/5) against CD38, one of the few well-characterized surface Ags present on myeloma cells. Since murine monoclonals have many disadvantages as human therapeutics, we prepared two engineered forms of the Ab: a CDR-grafted humanized IgG1 and a chimeric FabFc2 (mouse Fab cross-linked to two human gamma 1 Fc). To retain affinity in the humanized Ab, a number of changes were required to the human framework regions of the heavy chain. In particular, through systematic mutagenesis and computer modeling, we identified a critical interaction between the side chains of residues 29 and 78, which may be important for the humanization of other Abs. The properties of the humanized IgG1 and FabFc2 constructs were compared in a series of in vitro tests. Both constructs efficiently directed Ab-dependent cellular cytotoxicity against CD38-positive cell lines, but C was activated only poorly. Neither construct caused down-modulation of CD38, nor did they affect the NADase activity of CD38. Despite their differing structures, both Abs showed similar activity in most assays, although the humanized IgG1 was more potent at inducing monocyte cytotoxicity. These data represent the first direct comparison of CDR-grafted and chimeric FabFc2 forms of the same Ab, and offer no support for the perceived advantages of the FabFc2. These Abs show promise for therapy of multiple myeloma and other diseases involving CD38-positive cells.

Hepatic artery resistance changes in portal vein thrombosis

PURPOSE

To determine if portal vein thrombosis (PVT) is associated with changes in the hepatic artery resistive index (RI) at Doppler ultrasonography (US).

MATERIALS AND METHODS

In 35 patients with findings suspicious for PVT, prospective hepatic artery RIs were obtained before angiographic proof of portal vein status. RIs were also obtained from 27 age-matched patients with liver disease (without PVT) and from eight patients with PVT (without occlusion).

RESULTS

Twenty-seven of the 35 patients had proved PVT and a significantly lower (P < .01) mean hepatic artery RI than did patients in any other group studied. Twelve of these 27 patients had RI values of .50 or less, while none of the patients in any other group studied had an RI value this low (specificity, 100%).

CONCLUSION

A reduction in hepatic artery RI accompanies PVT and may be a helpful secondary sign to determine this venous abnormality.

Detection of degradation of magnetic resonance (MR) images: comparison of an automated MR image-quality analysis system with trained human observers

RATIONALE AND OBJECTIVES

The perceived need for magnetic resonance (MR) imaging quality control (QC) is occasionally minimized on the assumption that significant errors will be detected by the users. To evaluate the validity of this assumption, we compared the sensitivity of a test object and automated image analysis system for MR imaging QC with the sensitivity of trained human observers by evaluating images that were intentionally degraded.

METHODS

Parameters for imaging the test object and normal human volunteers were set to values that decreased the signal-to-noise ratio (SNR), caused distortion, and increased the slice thickness and separation.

RESULTS

The human observers were able to detect a 6-13% reduction in the SNR and distortions of more than 15% in human images. They were unable to identify 40% increases in the slice thickness. Automated analysis of test object images was able to detect all image degradations at the minimum levels applied.

CONCLUSION

The poor sensitivity of the human observers indicated that degradation, especially spatial measurements, could be significantly in error before being detected through visual analysis of clinical images. These errors would be detected by automated analysis of the test object used. Further investigation is needed to better define the accuracy with which quantitative image-quality analysis predicts the effects of degraded image quality on the ability of human observers to detect subtle abnormalities in clinical images.

Use of low-osmolar agents and premedication to reduce the frequency of adverse reactions to radiographic contrast media: a survey of the Society of Uroradiology

PURPOSE

To assess the decisions made by uroradiologists regarding choice of type of intravenous contrast material (low-osmolar contrast media [LOCM] vs conventional ionic agents) and frequency of use of corticosteroid prophylaxis.

MATERIALS AND METHODS

A questionnaire was mailed to 158 members of the Society of Uroradiology. There were 108 responses received, yielding a response rate of 68%. Results from 76 represented institutions were tabulated.

RESULTS

Most respondents practice at institutions in which LOCM are used selectively rather than universally. Corticosteroid prophylaxis in patients at risk is used with similar frequency at both types of institutions. There is considerable diversity in pretreatment regimens (ie, type and dose of corticosteroid used). Although antihistamines are used by many uroradiologists (almost always in conjunction with corticosteroids), H2 receptor antagonists are used at only a few institutions.

CONCLUSION

At institutions in which LOCM are used selectively, the majority of respondents use LOCM quite liberally, with most choosing these agents in patients at risk. Corticosteroid prophylaxis is widely used by respondents. There is much variation in the type of pretreatment regimen and its use in specific clinical settings.

CT-detected renal arterial calcification: correlation with renal artery stenosis on angiography

OBJECTIVE

The purpose of this study was to determine whether a relationship exists between CT-detected calcifications in the main renal artery and renal artery stenosis. We also evaluated whether renal artery calcifications are more indicative of stenosis in particular patient subgroups based on age, sex, or hypertensive status.

MATERIALS AND METHODS

We retrospectively reviewed the examinations of 70 patients (122 kidneys) undergoing both abdominal CT and angiography for various clinical conditions, most commonly evaluation of a tumor or aneurysm. CT studies were evaluated for degree of calcification at the orifice and in the proximal and distal segments of the main renal artery. The angiograms were evaluated for degree of narrowing. Renal artery stenosis was defined as a reduction in cross-sectional area of 75% or more. A separate analysis was performed on male and female patients above and below 65 years of age, with and without hypertension.

RESULTS

Renal arteries with clumps of calcium (> 3 mm in diameter) had a higher percentage of stenosis (7/16, 44%) than did renal arteries with less calcium (16/53, 30%), and renal arteries with no calcium had the fewest stenoses (9/53, 17%; p = .02). Calcifications in the renal artery were not good predictors of stenosis as they were frequently seen in arteries with nonsignificant narrowing and were occasionally seen in arteries with no narrowing. The patient's sex was not a significant factor in this analysis (p = .34). Renal artery calcifications in hypertensive patients showed a stronger association with renal artery stenosis, but the overall ability to predict stenosis remained poor. However, calcification may be significant in persons less than 65 years old, in whom this finding was associated with stenosis all three cases (100%). Similar calcifications in patients 65 years old or more were associated with stenosis in only 4 (31%) of 13 cases (p < .01).

CONCLUSION

CT-detected calcifications in renal arteries are associated with stenosis, but their predictive value in the general population or in hypertensive patients is poor. These calcifications in a patient less than 65 years of age are a better indicator of stenosis of the renal artery.

Retroperitoneal plexiform neurofibromas: CT findings

OBJECTIVE

CT findings in retroperitoneal plexiform neurofibromas have been described previously only in a few case reports. This study was performed to characterize the CT features in a larger group of patients with this benign neoplasm and to delineate those findings that suggest the presence of concurrent malignant tumors of the nerve sheath.

MATERIALS AND METHODS

From a review of CT scans showing retroperitoneal masses in 25 patients with neurofibromatosis type 1, we identified 16 patients whose clinical and CT features suggested the diagnosis of plexiform neurofibromas. The diagnosis was confirmed by biopsy of the mass in three patients. In the remaining 13 patients, the diagnosis was supported by long-term follow-up in eight and by biopsy confirmation of either a neurofibroma or a plexiform neurofibroma elsewhere in the body in the other five patients. Concurrent retroperitoneal malignant tumors of the nerve sheath were confirmed by biopsy in five patients.

RESULTS

CT showed bilateral, remarkably symmetric masses extending along the medial and posterior aspects of the psoas muscles in 15 of the 16 patients. Parapsoas masses tended to be long and cylindrical. In addition to parapsoas masses, eight patients had bilateral, symmetric masses extending along the anterior aspect of the sacrum in a sheetlike fashion. Masses were identified in the region of the celiac axis and the origin of the superior mesenteric artery in four patients. Only one patient had an isolated celiac/superior mesenteric artery mass without associated parapsoas or presacral masses. Retroperitoneal masses were of homogeneous, low attenuation when compared with adjacent muscle on CT images of 14 patients. Two patients had an unusual swirling and serpiginous pattern of increased attenuation superimposed on a low-attenuation background. Asymmetry in size and attenuation was due to malignant nerve sheath tumors in five patients.

CONCLUSION

Retroperitoneal plexiform neurofibromas have a characteristic appearance on CT scans. They are typically bilateral, symmetric, low-attenuation masses in a parapsoas or presacral location. Asymmetry in size and attenuation of a larger mass suggests the possibility of a malignant tumor of the nerve sheath. Recognition of the CT features of a retroperitoneal plexiform neurofibroma can obviate the expense, pain, and risk of an unnecessary biopsy. Conversely, detection of findings suggestive of malignant tumor can lead to appropriate recommendation of biopsy.

Renal duplex Doppler ultrasonography: a noninvasive predictor of kidney dysfunction and hepatorenal failure in liver disease

Hepatorenal failure, a well-recognized complication of established liver disease, is characterized by early renal hemodynamic changes (vasoconstriction) before clinically recognized kidney disease. This renal vasoconstriction (increased renal vascular resistance) should be detectable noninvasively by Doppler ultrasonography. We studied whether renal Doppler ultrasonography detects abnormalities in patients with nonazotemic liver disease and its prognostic value for subsequent kidney status. We observed by renal Doppler ultrasonography 180 patients who had liver disease without azotemia. A simple parameter, resistive index, was derived for each subject on the basis of Doppler waveform analysis. Traditional parameters used to assess patients with liver disease were also recorded at the time of Doppler ultrasonography. Subsequent kidney outcomes were kidney dysfunction (doubling of initial creatinine level to 1.5 mg/dl [133 mumol/L]) or more and the presence or absence of the hepatorenal syndrome. Abnormal results of Doppler examinations (elevated resistive index) were seen in 76 (42%) of the 180 patients. Kidney dysfunction developed in 55% (42/76) of the patients with an elevated resistive index and 6% (6/104) of those with normal results of Doppler study (p < 0.00005). Hepatorenal syndrome developed in 26% (20/76) of subjects with an elevated resistive index and 1% (1/104) of those with a normal resistive index (p < 0.00005). Cox regression analysis identified resistive index as a significant independent predictor of subsequent hepatorenal syndrome (p < 0.00005) and kidney dysfunction (p < 0.00005). Renal duplex Doppler ultrasonography can noninvasively identify a subgroup of nonazotemic patients with liver disease that is at significantly higher risk for subsequent development of kidney dysfunction and the hepatorenal syndrome.

Risk management issues in radial keratotomy surgery

In this article, reprinted from Ophthalmic Risk Management Digest, the bases for radial keratotomy-related claims and guidelines for avoiding such claims are discussed. In most lawsuits, it is not the procedure itself that is on trial, but the use of unusual technique, improper execution, or inadequacy of informed consent.

Staging of prostate cancer: results of Radiology Diagnostic Oncology Group project comparison of three MR imaging techniques

PURPOSE

To assess accuracy of three different magnetic resonance (MR) imaging techniques, including the endorectal coil, in staging prostate cancer.

MATERIALS AND METHODS

MR imaging was performed in 213 patients with prostate cancer with a conventional body coil, with fat suppression and a body coil, and with an endorectal coil. Radiologists identified tumor invasion into periprostatic tissues, neurovascular bundles, and seminal vesicles. Each technique was evaluated separately, and in a subset of 74 patients the three techniques were evaluated together. Images obtained with the two body-coil techniques were read in combination with images obtained with the endorectal coil (combination A) and alone (combination B).

RESULTS

Overall accuracy for conventional body-coil, fat-suppressed body-coil, and endorectal-coil MR was 61%, 64%, and 54%, respectively. Overall group accuracy for combinations A and B was 57% and 61%. Considerable interreader variability was found for combination A.

CONCLUSION

No technique was highly accurate for staging early prostate cancer. Individual radiologists did achieve a high degree of staging accuracy with the endorectal-coil and body-coil combination.

Intrarenal arterial Doppler sonography in the detection of renal vein thrombosis of the native kidney

OBJECTIVE

Previous studies of transplant kidneys and recent reports on native kidneys have suggested intrarenal arterial Doppler findings can be helpful in the noninvasive workup of renal vein thrombosis. We used arterial Doppler sonography to evaluate cases of possible acute renal vein thrombosis in native kidneys that had equivocal results on standard Doppler analysis of the renal vein.

MATERIALS AND METHODS

Twenty native kidneys in 12 patients with clinical findings suggestive of acute renal vein thrombosis had Doppler studies of the main renal vein that failed to show normal flow. In all 20 kidneys, duplex Doppler study of arcuate/interlobar intrarenal arteries was done and the resistive index was determined. The Doppler findings were compared with subsequent findings on either renal venograms (n = 11) or MR images (n = 9), which served as the reference "gold" standards.

RESULTS

The prevalence of renal vein thrombosis was 25% (5/20). Ten kidneys had very abnormal findings on arterial Doppler studies (absent or reversed end-diastolic flow), but only two of these were proved to have renal vein thrombosis. In six other kidneys, end-diastolic flow was identified but the resistive index was still elevated (> or = 0.70), and only one of these kidneys was proved to have renal vein thrombosis. Four kidneys had normal arterial Doppler studies, and 50% (two) of these were proved to have renal vein thrombosis. When absent or reversed end-diastolic flow was used as a sign of renal vein thrombosis, intrarenal arterial Doppler analysis had a sensitivity of 40% (2/5) and a specificity of 47% (7/15).

CONCLUSION

Unlike the reported experience in transplanted kidneys, intrarenal arterial Doppler analysis is neither sensitive nor specific for renal vein thrombosis in native kidneys. An intrarenal arterial Doppler study with normal findings should not prevent further workup if Doppler findings in the renal vein are equivocal, nor should absent or reversed end-diastolic arterial signals be considered highly suggestive of renal vein thrombosis.

MR imaging and sonography of early prostatic cancer: pathologic and imaging features that influence identification and diagnosis

OBJECTIVE

The purpose of this study was to correlate findings at MR imaging and transrectal sonography with histopathologic findings after surgery in patients with prostatic cancer, to identify the pathologic characteristics of prostatic cancer that improved detection with MR imaging and transrectal sonography, and to identify the imaging characteristics that correlated with detection of true cancers.

MATERIALS AND METHODS

Data from MR imaging in 320 patients and from transrectal sonography in 343 patients who were enrolled in the Radiological Diagnostic Oncology Group multiinstitutional study of imaging in prostatic cancer were correlated with results of radical prostatectomy. Only cancers 5 mm or greater in at least one dimension were evaluated pathologically. The locations of lesions and the linear dimensions and volumes of individual lesions and the prostate gland were evaluated pathologically and with imaging studies. The appearance of lesion margins on images and the degree of differentiation of lesions seen on pathologic examination were also studied. Univariate and multivariate analysis were performed to determine the pathologic findings associated with imaging detection and the imaging characteristics associated with prostatic cancer.

RESULTS

MR imaging and transrectal sonography showed 62% and 64% of cancers, respectively, each with a positive predictive value of 68%. Cancers that were larger, moderately or poorly differentiated, or located in the posterior half of the outer gland were easier to detect (p < .0001). The overall size of the prostate did not effect lesion detection. However, abnormalities identified in the posterior half of the outer gland were more likely to be cancers. On transrectal sonograms, larger abnormalities also were more likely to be malignant tumors. The sharpness of the margins of the imaged abnormalities did not predict pathologic status.

CONCLUSION

Detection of prostatic cancer with MR imaging or transrectal sonography is affected by cancer size, differentiation, and location; the odds of an imaged lesion's being malignant are related to location and, for transrectal sonography, size. Knowledge of anatomic/pathologic features that enhance lesion detection may help when using imaging tests to detect prostatic carcinoma. That certain imaging characteristics of lesions are associated with true cancers may assist in the interpretation of MR images and transrectal sonograms of the prostate.

Diabetic nephropathy: evaluation with renal duplex Doppler US

PURPOSE

To compare Doppler ultrasonography (US) with conventional clinical and laboratory tests in evaluation of diabetic renal disease.

METHODS

Ninety-eight patients with diabetes mellitus underwent renal Doppler (resistive index [RI] measurement) US examination. US data were compared with clinical variables and follow-up data.

RESULTS

Thirty-four diabetic patients without nephropathy had a mean RI of 0.62 +/- 0.09, which was not significantly different from the mean RI of 0.64 +/- 0.09 in 23 patients with early diabetic nephropathy. Patients with established nephropathy had a mean RI of 0.83 +/- 0.11, which was significantly (P < .001) higher than in the other two groups. Renal RI correlated highly with serum creatinine concentration (r = .64) and creatinine clearance rate (r = .80). An elevated RI (> or = 0.70) was associated with impaired renal function, increased proteinuria at 24 hours, and poor outcome. Absent diastole (RI = 1.0), observed in 7% of patients, was an ominous sign: Five of seven patients underwent dialysis or transplantation shortly after US.

CONCLUSION

RI is typically elevated in established nephropathy but is often normal in the early clinical stages of disease. Renal Doppler US provides an accurate indication of renal function in diabetic nephropathy but does not offer a great advantage over conventional tests.

MRI scanner variability studies using a semi-automated analysis system

Due to the unique design of the Parallel Rod Test Object (PRoTO) and the associated semi-automated analysis program, it was necessary to test it extensively for precision and accuracy, and preliminarily for utility, before its distribution for wider use in MRI system quality control (QC). The test object and analysis program measured the desired quantities reproducibly and they accurately measured predicted changes from intentionally adjusted imaging system parameters, yielding sensitivity of the various test measures to deviation in the system operating parameters. From a single scan of the most recent revision of the test object, multiple quantitative quality control measures were obtained throughout the scanning volume on two MR imaging systems over periods of six and twelve months, respectively. From these and earlier trials, an initial indication was obtained of which performance measures are worth monitoring for QC. This experience suggests that signal-to-noise ratio (SNR) and distortion (including display scale) should be monitored but not necessarily the resolution. The latter was only found to alter at the same time or later than other parameters such as SNR had changed. Slice thickness was found to vary on some units and this measure was also used in normalizing the SNR by voxel volume. SNR, distortion, and resolution measurements using field-echo sequences were less stable than those using spin-echo sequences. Use of this QC program to test a wide variety of image quality measures allowed timely assessment of the long-term variability of the units tested. Long-term variability may become among the most important measures for comparison of system performance and maintenance.(ABSTRACT TRUNCATED AT 250 WORDS)

Pelvic CT findings after radical prostatectomy

OBJECTIVE AND METHODS

To evaluate the spectrum of pelvic CT findings in patients who have had radical prostatectomy, we retrospectively evaluated the pelvic CT of 17 patients after surgery for prostate cancer. All patients were thought to be clinically free of local recurrence of carcinoma.

RESULTS

The bladder base was retropubic in 100%, the levator sling was well delineated in its entirety in only 88%, and fat was clearly demonstrated between the rectum and bladder base in only 44%. Unsuspected findings in this group included soft tissue density structures in the resected bed of the seminal vesicles (88%) and a transversely oriented, soft tissue density bar between the bladder base and rectum (53%). A variety of symmetric abnormalities are commonly seen on postprostatectomy pelvic CT.

CONCLUSION

Seminal vesical-like soft tissue structures are routinely visualized, and a horizontal bar of soft tissue in the rectovesical space is commonly demonstrated. These structures should not be confused with local tumor recurrence.

Renal duplex Doppler sonography in asymptomatic women during pregnancy

The purpose of this study was to establish the normal range of the renal RI in pregnant women. Maternal renal RIs were calculated in 61 asymptomatic pregnant patients with at least unilateral pyelocaliectasis. A mean RI was calculated for each kidney. Overall, the mean RI was 0.61 +/- 0.05. The renal RI was > or = 0.70 in 4% (5/121) of kidneys with no statistically significant difference between the mean right (0.62 +/- 0.06) and left (0.60 +/- 0.04) kidney RIs. There was no correlation between trimester of pregnancy or degree of pyelocaliectasis and RI.

CT of mullerian adenosarcoma arising in endometriosis

Mullerian adenosarcoma is a rare tumor that usually arises in the uterus. Occasional cases arising in endometrial implants have been reported. We report the computed tomography (CT) findings of histologically proven mullerian adenosarcoma arising in perirectal endometriosis in a 46-year-old woman.

Preclinical toxicology studies with azithromycin: genetic toxicology evaluation

Azithromycin was subjected to a series of three in vitro and one in vivo genetic toxicology assays for the detection of drug-associated gene or chromosomal effects. In the Ames Salmonella typhimurium tester strains TA1535, TA1537, TA98 and TA100, the presence of azithromycin was not associated with any increase in the number of his- revertants. Urine from mice dosed with up to 200 mg/kg of azithromycin also had no effect on the number of revertants in these same strains suggesting the absence of mutagenic excretory products following oral exposure. When tested up to the cytotoxic level of 240 micrograms/ml, azithromycin caused no increase in the mutant frequency at the thymidine kinase locus of L5178Y/TK cells. Both the mammalian and microbial gene mutation assays included the presence of rat-liver postmitochondrial (S9) fraction for the detection of mutagenic biotransformation products. Mitogen-stimulated human lymphocytes cultured in the presence of 2.5-7.5 micrograms/ml azithromycin for 24 h or 30.0-40.0 micrograms/ml azithromycin for 3 h in the presence of rat S9 had chromosomal aberration frequencies that were no different than negative control cells even though slight to moderate mitotic suppression was associated with these concentrations. In vivo assessment of this compound was completed in male and female mice with a single oral dose of 200 mg/kg followed by sacrifice at 6, 24 or 48 h later and metaphase analysis of bone marrow for chromosomal aberrations. No statistically significant elevations of chromosomally aberrant cells were found. We conclude that azithromycin does not cause gene mutations in microbial or mammalian cells, or chromosomal aberrations in cultured human lymphocytes or in mouse bone marrow in vivo.

Assessment of internal ureteral stent patency in patients with pyelocaliectasis: value of renal duplex sonography

OBJECTIVE

The purpose of this study was to evaluate duplex Doppler sonography in the assessment of internal ureteral stent patency.

SUBJECTS AND METHODS

Thirty-three kidneys with pyelocaliectasis and an internal stent were studied with Doppler sonography and conventional sonography. Stent patency was proved by subsequent contrast-enhanced studies, direct inspection of the stent after removal, or clinical follow-up.

RESULTS

The 11 kidneys with stent dysfunction had a significantly higher mean resistive index (0.78 +/- 0.08) than the 22 kidneys with patent stents (resistive index = 0.62 +/- 0.05) (p < .001). Eighty-two percent (9/11) of kidneys with occluded stents had elevated resistive indexes. The two occluded stents with normal resistive indexes were found in kidneys without significant obstruction before stent placement. Ninety-one percent (20/22) of patent stents were associated with a resistive index of less than 0.70. In the two cases of falsely elevated Doppler studies, the resistive index was obtained only 24-36 hr after placement of the stent; however, the resistive index was at least 10% less than that before stent placement. No significant correlation existed between degree of pyelocaliectasis shown on real-time sonography and stent status.

CONCLUSION

In the presence of pyelocaliectasis after placement of an internal ureteral stent, intrarenal Doppler sonography can be used to accurately distinguish between patency and obstruction. Real-time sonographic findings (degree of pyelocaliectasis) are not useful in this clinical situation.

Duodenal injuries caused by blunt abdominal trauma: value of CT in differentiating perforation from hematoma

OBJECTIVE

Traumatic duodenal perforation requires emergent surgery, whereas duodenal hematoma can often be treated nonsurgically. We assessed the CT findings in patients with blunt duodenal trauma to determine if CT can be used to differentiate these two duodenal injuries.

MATERIAL AND METHODS

Seven consecutive patients with blunt duodenal trauma (three with perforation, four with hematoma) who underwent CT as part of their initial diagnostic evaluation were included in the study. All three perforations and one of four hematomas were surgically proved. Diagnoses of duodenal hematoma in the other three patients were based on typical features on upper gastrointestinal studies and complete resolution of clinical findings after conservative treatment. The CT scans were retrospectively reviewed without knowledge of the specific type of duodenal injury, and the findings were correlated with the results of the gastrointestinal studies and surgical findings.

RESULTS

CT showed extraluminal gas or extravasated oral contrast material or both in the right anterior pararenal space in all three patients with duodenal perforation and in none of the patients with duodenal hematoma. Thickening of the duodenal wall and fluid in the right anterior pararenal space were seen in both groups of patients.

CONCLUSION

Although the number of patients in the study was small, the results suggest that CT may be useful in differentiating duodenal perforation from hematoma without perforation. Extraluminal gas or extravasated oral contrast material or both were seen in the right anterior pararenal space in all three patients who had perforation and in none of the patients who had hematoma alone.