Breakthrough adverse reactions to low-osmolar contrast media after steroid premedication.

OBJECTIVE: The purpose of this study was to review the nature of adverse reactions, or "breakthrough reactions," experienced by patients who received steroid premedication and low-osmolar contrast media. We compared the demographics of patients having these breakthrough reactions with those of patients who did not develop these reactions. MATERIALS AND METHODS: We retrospectively reviewed our radiology quality improvement database to identify patients with breakthrough reactions that occurred from January 1, 1994, through October 1, 1999, and we reviewed their medical records. We compared these patients with a control cohort of patients who had a history of prior adverse reaction to contrast media but no breakthrough reaction after administration of low-osmolar contrast media and premedication with corticosteroids. RESULTS: Over the 6-year period, 52 patients experienced 61 breakthrough reactions. The breakthrough reaction was mild in 76% of the patients. The breakthrough reaction was similar to the patient's initial adverse reaction in 85% of the patients. A history of seafood allergy or hay fever was statistically more likely to be identified in the breakthrough group than the control group. CONCLUSION: Breakthrough reactions occur in a substantial number of patients despite premedication with steroids and use of low-osmolar contrast agents. Typically the breakthrough reaction is of similar severity to the patient's initial reaction. Severe or life-threatening reactions are seen in 24% of patients.

Isolated pelvic deep venous thrombosis: relative frequency as detected with MR imaging.

PURPOSE: To determine the relative frequency of deep venous thrombosis (DVT) isolated to the pelvic veins, as demonstrated with magnetic resonance (MR) imaging. MATERIALS AND METHODS: The reports of 769 MR examinations performed from June 1993 through December 1999 in patients with suspected DVT were reviewed retrospectively. MR venography was performed by using a two-dimensional gradient-recalled-echo sequence (typically repetition time, 34 msec; echo time, 13 msec; flip angle, 60 degrees ). The presence of DVT was categorized by location in the pelvis, thigh, or calf. RESULTS: DVT was identified in 167 (21.7%) of the 769 MR examinations. Thirty-four (20.4%) of the 167 studies demonstrated DVT isolated to the pelvic veins. CONCLUSION: The relative frequency of isolated pelvic DVT detected with MR venography was higher than that reported in prior studies with ultrasonography (US) or ascending venography. MR venography should be performed in patients with suspected pelvic DVT or when clinical suspicion persists despite a negative US study.

The anterior iliac separation: alternative index for pelvic morphometry in fetuses with Down syndrome.

OBJECTIVE: The goal of this study was to assess the diagnostic use of an anterior iliac separation measurement as an alternative index for the iliac angle in the assessment of fetal pelvic morphometry. SUBJECTS AND METHODS: In 358 fetuses, the anterior iliac separation, iliac length, and iliac angle were prospectively measured on antenatal sonography. All measurements were obtained at two axial levels (superior and inferior). The gestational age of the fetus was recorded. The anterior iliac separation was normalized by iliac length, and coefficients of variation were calculated for all measurements. The effects of axial level and gestational age were assessed in a linear regression model. The diagnostic use of the anterior iliac separation relative to that of the iliac angle was assessed in a comparison of 24 fetuses with Down syndrome and 247 non-Down syndrome fetuses. RESULTS: The anterior iliac separation was less variable than the iliac angle at both superior and inferior levels. There were statistically significant effects for gestational age and axial level on both the anterior iliac separation and the iliac angle, but there was no significant effect for either factor when the anterior iliac separation was normalized by the iliac length. Comparing Down and non-Down syndrome fetuses, we found that the normalized anterior iliac separation had discriminating power similar to the iliac angle. CONCLUSION: The linear measurement of the anterior iliac separation has diagnostic properties similar to the iliac angle and is subject to less measurement variability. This simpler measurement may be particularly useful when normalized by the iliac length.

MRI of conjoined twins illustrating advances in fetal imaging.

Complex congenital fetal abnormalities are optimally evaluated with both ultrasound and magnetic resonance imaging. With the advent of ultrafast imaging sequences, fetal imaging has significantly improved. We present two cases of conjoined thoracoomphalopagus twins to discuss this unusual anomaly and to illustrate the recent advances in magnetic resonance imaging of the fetus.

Staging of pancreatic cancer before and after neoadjuvant chemoradiation.

Neoadjuvant chemoradiation therapy is used at many institutions for treatment of localized adenocarcinoma of the pancreas. Accurate staging before neoadjuvant therapy identifies patients with distant metastatic disease, and restaging after neoadjuvant therapy selects patients for laparotomy and attempted resection. The aims of this study were to (1) determine the utility of staging laparoscopy in candidates for neoadjuvant therapy and (2) evaluate the accuracy of restaging CT following chemoradiation. Staging laparoscopy was performed in 98 patients with radiographically potentially resectable (no evidence of arterial abutment or venous occlusion) or locally advanced (arterial abutment or venous occlusion) adenocarcinoma of the pancreas. Unsuspected distant metastasis was identified in 8 (18%) of 45 patients with potentially resectable tumors and 13 (24%) of 55 patients with locally advanced tumors by CT. Neoadjuvant chemoradiation therapy and restaging CT were completed in a total of 103 patients. Thirty-three patients with potentially resectable tumors by restaging CT underwent surgical exploration and resections were performed in 27 (82%). Eleven (22%) of 49 patients with locally advanced tumors by restaging CT were resected, with negative margins in 55%; the tumors in these 11 patients had been considered locally advanced because of arterial involvement on restaging CT. Staging laparoscopy is useful for the exclusion of patients with unsuspected metastatic disease from aggressive neoadjuvant chemoradiation protocols. Following neoadjuvant chemoradiation, restaging CT guides the selection of patients for laparotomy but may overestimate unresectability to a greater extent than does prechemoradiation CT.

Nonenhanced helical CT and US in the emergency evaluation of patients with renal colic: prospective comparison.

PURPOSE: To compare nonenhanced helical computed tomography (CT) with ultrasonography (US) for the depiction of urolithiasis. MATERIALS AND METHODS: During 9 months, 45 patients (mean age, 44 years; mean weight, 92.5 kg) prospectively underwent both nonenhanced helical CT (5-mm collimation; pitch of 1.5) and US of the kidneys, ureters, and bladder. US evaluation included a careful search for ureteral calculi. Presence of calculi and obstruction and incidental diagnoses were recorded. Clinical, surgical, and/or imaging follow-up data were obtained in all patients. The McNemar test was used to compare groups. RESULTS: Diagnoses included 23 ureteral calculi and one each of renal cell carcinoma, appendicitis, ureteropelvic junction obstruction, renal subcapsular hematoma, cholelithiasis, medullary calcinosis, and myelolipoma. CT depicted 22 of 23 ureteral calculi (sensitivity, 96%). US depicted 14 of 23 ureteral calculi (sensitivity, 61%). Differences in sensitivity were statistically significant (P: =.02). Specificity for each technique was 100%. When modalities were compared for the detection of any clinically relevant abnormality (eg, unilateral hydronephrosis and/or urolithiasis in patients with an obstructing calculus), sensitivities of US and CT increased to 92% and 100%, respectively. One case of appendicitis was missed at US, whereas medullary calcinosis and myelolipoma were missed at CT. CONCLUSION: Nonenhanced CT has a higher sensitivity for the detection of ureteral calculi compared with US.

Radiologic manifestations of sclerosing cholangitis with emphasis on MR cholangiopancreatography.

Magnetic resonance cholangiopancreatography (MRCP) is a relatively new, noninvasive cholangiographic technique that is comparable with invasive endoscopic retrograde cholangiopancreatography (ERCP) in the detection and characterization of extrahepatic bile duct abnormalities. The role of MRCP in evaluation of the intrahepatic bile ducts, especially in patients with primary or secondary sclerosing cholangitis, is under investigation. The key cholangiographic features of primary sclerosing cholangitis are randomly distributed annular strictures out of proportion to upstream dilatation. As the fibrosing process worsens, strictures increase and the ducts become obliterated, and the peripheral ducts cannot be visualized to the periphery of the liver at ERCP. In addition, the acute angles formed with the central ducts become more obtuse. With further progression, strictures of the central ducts prevent peripheral ductal opacification at ERCP. Cholangiocarcinoma occurs in 10%-15% of patients with primary sclerosing cholangitis; cholangiographic features that suggest cholangiocarcinoma include irregular high-grade ductal narrowing with shouldered margins, rapid progression of strictures, marked ductal dilatation proximal to strictures, and polypoid lesions. Secondary sclerosing and nonsclerosing processes can mimic primary sclerosing cholangitis at cholangiography. These processes include ascending cholangitis, oriental cholangiohepatitis, acquired immunodeficiency syndrome-related cholangitis, chemotherapy-induced cholangitis, ischemic cholangitis after liver transplantation, eosinophilic cholangitis, and metastases.

Normal fetal pelvis: important factors for morphometric characterization with US.

PURPOSE: To prospectively evaluate iliac angle and iliac length in a large number of normal fetuses and to identify factors that may influence these measurements. MATERIALS AND METHODS: At antenatal ultrasonography (US) in 356 fetuses, the iliac angle and iliac length were measured at two axial levels (superior and inferior). In mixed linear models, the statistical significance and magnitude of effect on the measurement of iliac angle and iliac length were estimated for gestational age, fetal sex, maternal diabetes status, axial level, and spine position relative to the transducer. RESULTS: Statistically significant effects were found for gestational age, axial level, and spine orientation but not for fetal sex or maternal diabetes status. The iliac angle was found to decrease by 15.7 degrees from the superior to inferior portion of the pelvis, decrease by approximately 0.37 degrees /wk, and decrease by as much as 15.6 degrees when the spine is directed to the side. Iliac length was found to increase by 0.8 mm/wk from 13 weeks to term, decrease by 1.2 mm from the superior to the inferior portion of the pelvis, and increase by as much as 1.29 mm when the spine is not directly subjacent to the transducer. CONCLUSION: The axial level of measurement, gestational age, and spine orientation must be accounted for if these morphometric indexes are used to discriminate fetuses with and those without Down syndrome.

Pelvic CT morphometry in Down syndrome: implications for prenatal US evaluation--preliminary results.

PURPOSE: To characterize pelvic morphometric differences in patients with and those without Down syndrome by using computed tomography (CT) and to determine useful indexes for ultrasonographic (US) evaluation. MATERIALS AND METHODS: Pelvic CT scans in seven patients with Down syndrome and in 27 patients without Down syndrome were reviewed. Iliac angle, iliac length, sacroiliac joint angle, and anterior iliac wing separation were measured at superior, middle, and inferior transverse sacral levels. The effects of chromosomal status and transverse level were evaluated statistically. RESULTS: Significant differences were found for mean iliac angle (P < .007) and length (P < .005) between patients without Down syndrome (angle, 75 degrees; length, 8.4 cm) and those with Down syndrome (angle, 82 degrees; length, 7.5 cm). Depending on the level of measurement, variations in iliac angle between patients without and those with Down syndrome were as much as 13 degrees and 15 degrees, respectively, and variations in length were as much as 1.6 cm and 0.9 cm, respectively. The greatest differences were at the middle sacral level. Sacroiliac joint angle and the anterior iliac wing separation were not different between groups. CONCLUSION: Patients with Down syndrome had a larger mean iliac angle and a shorter mean iliac length. The most pronounced differences were at the middle sacral level, which suggests that this may be the optimal level for measuring these parameters at prenatal US.

Imaging-guided percutaneous biopsy of focal splenic lesions: update on safety and effectiveness.

OBJECTIVE: The purpose of this study is to determine the safety and effectiveness of percutaneous imaging-guided biopsy in the diagnosis of focal splenic lesions. MATERIALS AND METHODS: From May 1995 to November 1997, 20 imaging-guided biopsies of focal splenic lesions were performed in 18 patients, including seven patients with a prior diagnosis of extrasplenic malignancy (breast cancer, n = 3; lymphoma, n = 2; ovarian cancer, n = 1; and osteogenic sarcoma, n = 1), three immunosuppressed patients (cause of immunosuppression: AIDS, n = 1; liver transplantation, n = 1; and bone marrow transplantation, n = 1), two patients with anemia, one patient with a recent history of IV drug abuse, and five patients with incidentally discovered splenic lesions. Biopsies were performed with an 18-gauge (n = 1), a 20-gauge (n = 8), or a 22-gauge (n = 14) self-aspirating needle or an 18-gauge cutting needle (n = 1). Biopsies were considered successful if a specific diagnosis of benign or malignant disease was made. RESULTS: A specific diagnosis was made in 16 (88.9%) of 18 patients, and no complications occurred. Malignancy was diagnosed in six patients including three patients with lymphoma. Benign conditions were diagnosed in 10 patients: a cyst in two patients; hamartoma in one; lipogranuloma in one; infarct in one; and infection in four, including one case each of Candida albicans, Pneumocystis carinii, Mycobacterium tuberculosis, and mixed flora. The tenth benign diagnosis was a pseudotumor of the spleen related to a bulbous tail of the pancreas that was inseparable from the splenic hilum. Biopsy did not establish a diagnosis in one patient with lymphoma and in one patient with presumed splenic candidiasis. A mean of 1.5 needle passes was made per biopsy. CONCLUSION: Imaging-guided splenic biopsy is a safe technique that provides a specific diagnosis in most patients with focal splenic lesions.

PACS in sonography: accuracy of interpretation using film compared with monitor display. Picture archiving and communication systems.

OBJECTIVE: The goal of this study was to determine the relative accuracy of interpretation of sonography when viewed on a monitor or on film. MATERIALS AND METHODS: Four radiologists twice interpreted a series of 440 sonograms using the following sequences of display formats for initial and second interpretations: film-film, film-monitor, monitor-film, and monitor-monitor. Reporting discrepancies between the initial and subsequent interpretation were reviewed by an arbitration panel unaware of the display mode. Results were analyzed for differences in error rate attributable to film versus monitor display format, chronology of interpretation, individual observer, and observer seniority. RESULTS: We found no statistically significant difference in the error rate for film (10.3%) versus monitor display format (14.6%) (p = .09). Likewise, we found no significant differences in the error rates attributable to chronology of interpretation (p = .13), individual observer (p = .54), or observer seniority (p = .87). CONCLUSION: Interpretative accuracy is similar whether sonograms are interpreted on a monitor or on film.

Vaginal opacification during defecography: direction of vaginal migration aids in diagnosis of pelvic floor pathology.

BACKGROUND: To determine whether direction of vaginal displacement during defecography aids in diagnosing pelvic floor pathology. METHODS: Ninety patients underwent defecography over a 2-year period. Each study was retrospectively reviewed by three radiologists who recorded whether the vagina was displaced cephalad, caudad, or nondisplaced in relation to the urogenital hiatus. This information was then correlated with radiologic diagnosis rendered for the study. RESULTS: Of the 26 patients with normal defecograms, 19 (73%; p < 0. 001) demonstrated no vaginal displacement during the procedure. Comparatively, 10 (83%; p < 0.001) of the 12 patients with cystoceles showed caudad vaginal displacement, and no patients with cystoceles showed cephalad displacement of the vagina. Of the 17 patients with rectoceles, 10 (58%) showed cephalad displacement, one (6%) showed caudad displacement, and six (35%) patients showed no vaginal displacement. Thirteen (46%) of 28 patients with enteroceles showed cephalad vaginal displacement, nine (32%) showed no vaginal displacement, and six (21%) demonstrated caudad displacement. CONCLUSIONS: Caudad displacement of the opacified vagina suggests the presence of a cystocele. Cephalad vaginal displacement is suggestive of the presence of an enterocele or rectocele.

Vaginal opacification during defecography: utility of placing a folded gauze square at the introitus.

We evaluated the value of placement of a folded gauze square into the urogenital introitus to improve vaginal opacification in 90 patients who underwent defecography. Of the 50 patients who retained the gauze in the introitus, 96% demonstrated excellent or good vaginal opacification. By contrast, only 75% of the 40 patients who lost the gauze during the study were able to achieve the same level of opacification. This difference was shown to be statistically significant (p < 0.002), suggesting that placement of a folded gauze square in the introitus limits loss of contrast from the vagina, which improves vaginal opacification.

Interobserver variability in the interpretation of unenhanced helical CT for the diagnosis of ureteral stone disease.

PURPOSE: The purpose of this study was to analyze interobserver agreement in the interpretation of unenhanced helical CT (UHCT) for the evaluation of ureteral stone disease and obstruction. METHOD: One hundred three UHCT examinations were independently and retrospectively reviewed by five readers including attending radiologists, a radiology resident, and an attending urologist. Examinations were interpreted as positive, negative, or indeterminate for ureteral stone disease and obstruction. The Cohen kappa test was used to measure interobserver agreement. The accuracy of the readers was also assessed. RESULTS: The kappa value ranged from 0.67 to 0.71 among the three attending radiologists and from 0.65 to 0.67 among the radiology attending physicians and radiology resident. Although the urologist tended to agree less well with the other readers (kappa range: 0.33-0.46), there was no statistically significant difference (p < 0.05) in the accuracy among all five readers. The percentage of cases interpreted as indeterminate ranged from 8 to 25% and almost invariably involved difficulty distinguishing phleboliths from minimally obstructing distal ureteral calculi. The percentage of UHCT scans correctly interpreted as positive and correctly interpreted as negative ranged from 73% (n = 27) to 86% (n = 32) and 63% (n = 22) to 86% (n = 30), respectively. CONCLUSION: Interobserver agreement was very good among the radiology attending physicians and resident and moderate with the urologist. The examination is an accurate technique in the evaluation of ureteral stone disease, although limitations exist, particularly in the diagnosis of minimally obstructing distal ureteral calculi.

Predictive model for the diagnosis of intraabdominal abscess.

RATIONALE AND OBJECTIVES: The authors investigated the use of an artificial neural network (ANN) to aid in the diagnosis of intraabdominal abscess. MATERIALS AND METHODS: An ANN was constructed based on data from 140 patients who underwent abdominal and pelvic computed tomography (CT) between January and December 1995. Input nodes included data from clinical history, physical examination, laboratory investigation, and radiographic study. The ANN was trained and tested on data from all 140 cases by using a round-robin method and was compared with linear discriminate analysis. A receiver operating characteristic curve was generated to evaluate both predictive models. RESULTS: CT examinations in 50 cases were positive for abscess. This finding was confirmed by means of laboratory culture of aspirations from CT-guided percutaneous drainage in 38 patients, ultrasound-guided percutaneous drainage in five patients, surgery in five patients, and characteristic appearance on CT scans without aspiration in two patients. CT scans in 90 cases were negative for abscess. The sensitivity and specificity of the ANN in predicting the presence of intraabdominal abscess were 90% and 51%, respectively. Receiver operating characteristic analysis showed no statistically significant difference in performance between the two predictive models. CONCLUSION: The ANN is a useful tool for determining whether an intraabdominal abscess is present. It can be used to set priorities for CT examinations in order to expedite treatment in patients believed to be more likely to have an abscess.

Early systole in the healthy kidney: variability of Doppler US waveform parameters.

PURPOSE: To determine the sampling variability of intrarenal Doppler ultrasound (US) indexes of early systole in a screened population of healthy individuals. MATERIALS AND METHODS: Doppler US measurements were obtained in the superior, middle, and inferior regions of 132 kidneys in 66 healthy, potential kidney donors. All individuals subsequently underwent angiography. Systematic measurement differences and random effects were estimated for sampling from a particular parenchymal region, from a kidney in a subject, from an individual in a population, and from a vascular territory. RESULTS: Coefficients of variations ranged from 20% to 30%. Most (55%-66%) of the observed variation was attributable to random differences between repeated measurements in the same kidney. No systematic variations attributable to kidney region, vascular territory, right versus left kidney, or subject age were found for acceleration time, acceleration, or waveform shape. Some evidence of fixed variation between kidneys and between regions was found for peak systolic velocity, but the magnitude of this variation was small. Averages of repeated measurements may decrease the probability of exceeding the normal threshold for acceleration but not for acceleration time. CONCLUSION: Measurements of Doppler parameters of the early systole have substantial intrinsic variability. Thus, caution is needed when interpreting small changes in these measurements within a kidney or between individuals.