Preoperative evaluation of potential renal donors using multidetector CT.

Preoperative knowledge of vascular anatomy and parenchymal disease is critical in patients undergoing laparoscopic donor nephrectomy. Multidetector computed tomography represents a substantial improvement in technology that lends itself to the comprehensive evaluation of renal donors. We describe and illustrate our computed tomographic technique in patients considering a donor nephrectomy.

Compression CT urography: a comparison with IVU in the opacification of the collecting system and ureters.

OBJECTIVE: The purpose of this study was to evaluate opacification of the collecting system and ureters using compression computed tomography (CT) urography compared with conventional intravenous urography (IVU). MATERIALS AND METHODS: Fifty consecutive patients underwent compression CT urography as part of a dedicated renal CT. A compression belt was applied prior to nephrographic phase imaging. Excretory phase scans were acquired through the kidneys 3 minutes post injection with the compression belt in place. The compression belt was then released, and scans were obtained through the ureters. Three independent readers then scored opacification of the collecting system and ureters on a scale of 0-2 (0 = no opacification, 1 = partial opacification, 2 = full opacification and distension). Fifty consecutive nonmatched IVUs were scored by segment by the same readers. Comparison of the two modalities was made using the Mann-Whitney U test. Interobserver agreement was assessed by the Kappa coefficient. RESULTS: CT demonstrated significantly better opacification (p < or = 0.02) of the upper and lower pole pelvicalyceal systems and midureters bilaterally. There was no difference in opacification of the proximal and distal ureters by CT compared with IVU. The Kappa coefficient was 0.53. CONCLUSIONS: Compression CT urography yields equal or better opacification of the collecting system and ureters when compared with IVU, and shows promise for the routine evaluation of the renal excretory system.

Validity of cultures of fluid collected through drainage catheters versus those obtained by direct aspiration.

To examine the validity of cultures of fluid collected through drainage catheters, we reviewed retrospectively fluid specimens that had been collected through catheters in place for at least 2 days. These specimens were taken from patients at a large tertiary-care hospital. A total of 974 specimens representing 620 patient episodes were received. For 554 (89%) episodes there was no reliable imaging evidence for localized infection, rendering the results uninterpretable. The remaining 66 (11%) episodes were followed within 2 days by radiologically guided or open aspiration of one or more fluid collections (predominantly in the abdomen or pelvis) near the drainage catheter, allowing comparison of culture results of 59 direct aspirates with those of prior catheter drainage. In 33 (56%) of these 59 cases, matched culture results were equivalent for therapeutic decision making. However, relying on results of catheter drainage cultures would have led to inadequate antimicrobial therapy in 13 (22%) cases, to excessive therapy in 11 (19%) cases, and to both in 2 cases (3%). We conclude that radiological imaging should be standard practice in the assessment of deep-tissue infections in patients with drainage catheters, and that direct aspiration of potentially infected fluid collections is the most reliable method of obtaining specimens for culture that should be used to guide therapy.

Transjugular intrahepatic portosystemic shunts (TIPS): effects of respiratory state and patient position on the measurement of Doppler velocities.

OBJECTIVE: The purpose of this prospective study was to examine the effects of patient position and respiratory state on the measurements of Doppler velocities in transjugular intrahepatic portosystemic shunts. SUBJECTS AND METHODS: Thirty-eight transjugular intrahepatic portosystemic shunts in 34 consecutive patients were studied using Doppler sonography. Peak velocities were measured in the mid shunt with the patient in three positions (supine, sitting upright, and left lateral decubitus) and two respiratory states (deep inspiration and quiet respiration). A mixed linear regression model was used to assess statistically significant differences among the six velocity measurements. RESULTS: Peak velocities in the mid stent averaged 22 cm/sec greater in quiet respiration than in deep inspiration, which was a significant difference (p < 0.00001). Differences in velocities in the three patient positions were not significant (p = 0.53). Using 90-190 cm/sec as the normal range, the peak velocity shifted from normal to abnormal levels by changing respiratory state in 17 (45%) of 38 studies. Using 60 cm/sec as the lower normal limit, the peak velocity fell below the normal range with inspiration in 10 (26%) of 38 studies. In 12 (32%) of 38 studies, a decline in peak velocity exceeding 50 cm/sec could be induced by inspiration. CONCLUSION: Peak systolic velocity in transjugular intrahepatic portosystemic shunts is substantially altered by the respiratory state of the patient at the time of the measurement, but not by the patient position. Respiratory state must be taken into account in the interpretation of peak velocity for shunt stenosis.

Multiple fluid collections: CT- or US-guided aspiration--evaluation of microbiologic results and implications for clinical practice.

PURPOSE: To determine if patients with multiple fluid collections need every collection aspirated and if cross-contamination is a risk if separate sterile procedures are not followed for each aspiration. MATERIALS AND METHODS: Records from 1,076 imaging-guided percutaneous aspirations and drainages over 39 months were retrospectively reviewed; 124 patients had multiple fluid collections drained, which yielded 287 aspirates. The patients were divided into two groups: those (n = 82) with multiple collections aspirated on any 1 day, and those (n = 61) with multiple collections aspirated over 10 days. Nineteen patients were included in both groups. Gram stain microscopy and culture results were compared between sequential aspirates in each patient, and their potential effects on antimicrobial therapy and theoretic risk for cross-contamination were evaluated. RESULTS: In 82 patients undergoing multiple aspirations on any 1 day, multiple microorganisms differed in 32 patients, which indicated a need for therapy change in 18 (22%) patients. In 61 patients undergoing aspiration on different days, microorganisms differed in 32 patients, which indicated a need for therapy change in 15 (25%) patients. Cross-contamination could have occurred in 28 of 93 (30%) aspirates from patients with a second or subsequent collection if separate sterile procedures had not been undertaken. CONCLUSION: When multiple fluid collections are identified, aspirates from all collections should be obtained through separate sterile procedures to ensure optimal antimicrobial coverage and avoid cross-contamination.

Transrectal sonography in staging rectal carcinoma: the role of gray-scale, color-flow, and Doppler imaging analysis.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of combining gray-scale sonography with color-flow imaging and pulsed Doppler transrectal sonography in the staging of rectal carcinoma. SUBJECTS AND METHODS: Thirty-nine patients with primary rectal carcinoma underwent transrectal sonography. The rectal masses were staged T1-T2 or T3-T4 on the basis of gray-scale imaging. The local nodes were classified as benign or malignant on the basis of size and echogenicity. In 22 patients, color-flow imaging and pulsed Doppler imaging of the rectal mass and of the local lymph nodes were performed. The peak systolic velocity (PSV) and end diastolic velocity were documented, and the resistive index was calculated. RESULTS: Gray-scale imaging alone was used to stage T1-T2 masses with 88% sensitivity and 82% specificity. T3-T4 masses were staged with 82% sensitivity and 88% specificity. Overall accuracy was 85%. Gray-scale imaging of lymph nodes using a discriminatory size of less than or equal to 5 mm for benign nodes and greater than 5 mm for malignant nodes yielded a sensitivity of 100%, a specificity of 28%, and an accuracy of 52%. Using receiver operating characteristic curve analysis, we determined that a size of greater than or equal to 7 mm was optimal for characterizing nodes. Such a size provided an accuracy of 83%. PSV of less than 25 cm/sec distinguished T3-T4 from T1-T2 rectal masses with 75% sensitivity, 80% specificity, and 77% accuracy. A PSV of greater than 20 cm/sec classified a node as malignant with 100% sensitivity, 62% specificity, and 76% accuracy. A resistive index of greater than 0.61 classified a node as malignant with 71% sensitivity, 85% specificity, and 80% accuracy. CONCLUSION: Color-flow imaging and pulsed Doppler imaging are useful additions to gray-scale transrectal sonography in staging primary rectal carcinomas. The combination has most value when evaluating perirectal nodes.

Soft-tissue "rim" sign in the diagnosis of ureteral calculi with use of unenhanced helical CT.

PURPOSE: To determine the value of the ureteric soft-tissue "rim" sign for differentiation of ureteral calculi from phleboliths on unenhanced helical computed tomographic (CT) scans and to identify factors that are associated with the presence of the rim sign. MATERIALS AND METHODS: Of 442 patients with ureteral obstruction confirmed at CT, 200 had documented ureteral stone disease; 136 of these patients had ureteral calculi, excluding the ureterovesical or ureteropelvic junctions. Each calculus and phlebolith along the course of the ureter were evaluated retrospectively and blindly for the presence of the rim sign, stone location, and stone size; the duration of symptoms was documented when available. RESULTS: The rim sign was present in 105 of 136 ureteral calculi (77%) and in 20 of 259 phleboliths (8%) and yielded a sensitivity of 77% and a specificity of 92% for distinguishing a calculus from a phlebolith. Calculi associated with the rim sign had a mean size of 4.3 mm, and calculi without a rim sign had a mean size of 6.3 mm (P < .001). There was no difference in duration of symptoms among patients who did or did not exhibit a rim sign. CONCLUSION: In patients with flank pain, the presence of a rim sign is a strong indicator that a calcification along the course of the ureter is a stone. Absence of the rim sign indicates that a calcification remains indeterminate.

Evaluation of quantitative CT vertebral bone mineral density measurement and the Singh index in elderly females with hip fractures--a case control study.

This study aims to evaluate the ability of quantitative computed tomography (QCT) bone mineral density (BMD) measurement of vertebral bodies to predict risk of hip fracture. We also examine the predictive value of the radiographic Singh index and its relationship to the vertebral BMD. The vertebral BMD (using a QCT protocol) and radiographic Singh index were evaluated in 86 white females who had sustained a hip fracture after minor trauma. 86 age-matched female controls were also studied. All patients were post-menopausal, the age range was 52-95 years. BMD values were found to be low in both the study group and controls; there was no statistically significant difference between the groups. A low Singh index did not correlate with hip fracture, nor did it correlate with low vertebral BMD measurement. We conclude that vertebral BMD and radiographic Singh index are not reliable predictors of hip fracture in the elderly female.

Pain and increased mammographic density in women receiving hormone replacement therapy: a prospective study.

OBJECTIVE: A prospective study was designed to evaluate the effects of hormone replacement therapy on mammographic density in postmenopausal women. The possible association of breast pain with increased mammographic density was evaluated. SUBJECTS AND METHODS: Thirty-three postmenopausal women undergoing hormone replacement therapy for a mean of 11 months had mammography before and after commencing treatment. As a control, 31 postmenopausal women who never had hormone therapy also had baseline and follow-up mammograms after a mean of 13 months. Subjects were asked whether breast pain, which they graded as mild, moderate, or severe, had developed since their entry into the study. Baseline and follow-up mammograms were assessed objectively and subjectively for interval changes in density. The presence of breast pain was correlated with changes in density on the mammograms. RESULTS: A subjective increase in mammographic density was seen in nine (27%) of the women taking hormones and in none of the control subjects (p = .002). Changes were focal in four, multifocal in four, and diffuse in one. An increase in density was seen with all types of treatment used, and was noted as early as 4 months after the start of treatment. Seven (78%) of nine patients with mammographic changes had breast pain, which they classed as moderate or severe, that had developed since the start of treatment. In five patients with mild or moderate breast pain, an increase in density was not shown on mammograms. Of the 21 women taking hormones who did not have breast pain, increased density on follow-up mammograms was shown in only two (p = .004). None of the patients in the control group had breast pain. CONCLUSION: Focal, multifocal, or diffuse mammographic increases in density occur in a significant percentage of women undergoing hormone replacement therapy. A large proportion of these women have breast pain. Increased mammographic density appears to be associated with breast pain in women receiving hormones. This has implications for mammography in women receiving hormone replacement therapy.