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.

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.

Three-dimensional CT of the genitourinary tract.

The applications of three-dimensional (3D) CT techniques encompass a spectrum from calculus disease to preoperative planning. With proper selection of display windows and levels, accurate measurement of stone size can be achieved, along with volumetric information. A CT scan with reconstruction may help guide the direction of an endopyelotomy incision away from crossing vessels. The benefits of 3D CT in the evaluation of living renal donors include lower cost and decreased patient morbidity. In renal allograft recipients and other patients, the study may be used to investigate hypertension. Also, 3D CT is invaluable in planning nephron-sparing surgery for renal masses. The ultimate role of this modality rests in the hands of clinicians who can benefit from them and the radiologists who must provide the high-quality images and the interpretive expertise.

Vaginitis emphysematosa: CT and review of the literature.

OBJECTIVE: This report describes the CT appearance of vaginitis emphysematosa. CONCLUSION: Vaginitis emphysematosa is characterized by gas-filled cysts in the vaginal wall, in a pattern similar to pneumatosis of the intestines or bladder. This bacterial vaginitis is benign and self-limited and does not signify the presence of tissue necrosis or life-threatening infection.

Evaluation of pseudoenhancement of renal cysts during contrast-enhanced CT.

OBJECTIVE: The purpose of our study was to evaluate renal cyst pseudoenhancement during helical CT in a phantom model and in patients. MATERIALS AND METHODS: Iodine baths containing water-filled spheres and cylinders were constructed to simulate cysts in enhancing renal parenchyma. Iodine concentration, cyst size and location, collimation, and peak kilovoltage were varied and cyst attenuation was measured. Data were analyzed with the mixed linear models and Mantel-Haenszel tests. Subsequently, a paired t test compared CT attenuation values before and after contrast material enhancement in 40 patients with 68 renal cysts (radiographic stability >3 months). RESULTS: The attenuation values of phantom cysts increased when placed in a contrast media bath (p = 0.001). The increase in attenuation values became more pronounced with increasing iodine concentrations, decreasing peak kilovoltage, and smaller sphere sizes. In patients, mean cyst attenuation increased 3.4 +/- 6.2 H after administration of contrast material (p = 0.00002). The attenuation did not increase more than 10 H in any of the 37 cysts larger than 2 cm found in patients. Eight (26%) of the 31 cysts smaller than 2 cm found in patients increased by at least 10 H. CONCLUSION: In a phantom model, at simulated physiologic levels of renal enhancement, cysts may pseudoenhance by more than 10 H. Similarly, in patients, cysts may also pseudoenhance; however, most pseudoenhancement does not exceed 10 H. In patients, pseudoenhancement of at least 10 H is more likely in cysts smaller than 2 cm.

Lung cancer staging and management: comparison of contrast-enhanced and nonenhanced helical CT of the thorax.

PURPOSE: To determine whether contrast material-enhanced helical computed tomography (CT) of the thorax and upper abdomen changes the tumor stage and management compared with nonenhanced helical CT in patients with newly diagnosed lung cancer. MATERIALS AND METHODS: During 15 months, any patient in whom lung cancer was strongly suspected or newly diagnosed and who was scheduled for thoracic CT was considered eligible for the study. All patients underwent nonenhanced thoracic helical CT from the lung apices through the adrenal glands and then contrast-enhanced thoracic helical CT from the lung apices through the entire liver. Each study was read independently, and the thoracic radiologic stage was determined. Tissue sampling was performed and the final pathologic stage assigned. RESULTS: Ninety-six patients had a final pathologic diagnosis of lung cancer. There was agreement in stage between the nonenhanced and contrast-enhanced examinations in 92 of the 96 patients. In three patients, the tumor stage at nonehanced CT increased at contrast-enhanced CT, from IA to IIA (n = 1), IIB to IV (n = 1), and IIIB to IV (n = 1). In one patient, the tumor stage decreased from IIIB to IIB. There was no substantial change in management of any patient. CONCLUSION: The results suggest that contrast-enhanced thoracic CT through the liver for staging lung cancer rarely changes the tumor stage determined with nonenhanced CT through the adrenal glands and does not substantially influence management decisions.

Renal lymphoma in an azotemic patient--usefulness of magnetic resonance imaging.

An azotemic patient benefited from diagnostic magnetic resonance imaging (MRI) in the evaluation of his renal mass. This led to suspicion of lymphoma, and provided guidance for percutaneous biopsy. Chemotherapy was then initiated, and an unnecessary nephrectomy was avoided. After a year of follow-up, evolution was stable and renal function significantly improved.

Pancreatic transplantation using portal venous and enteric drainage: the postoperative appearance of a new surgical procedure.

PURPOSE: To review the normal radiologic appearance of pancreatic transplants that use portal venous and enteric drainage, and to review the appearance of a variety of postoperative complications. METHOD: We retrospectively reviewed the computed tomographic (CT) scans, magnetic resonance (MR) images, and ultrasounds of patients who had undergone pancreatic transplantation using portal venous and enteric drainage. RESULTS: At CT, the normal pancreatic transplant appears as a heterogeneous mass composed of pancreatic parenchyma, vessels, and omental wrap. On MR imaging, a normal transplant demonstrates intermediate signal intensity on T1- and T2-weighted sequences. Sonographic evaluation of a normal transplant reveals a hypoechoic gland that contains readily detectable low-resistance arterial and venous Doppler waveforms. Acute postoperative complications include acute rejection, which has a nonspecific radiologic appearance, and transplant pancreatitis, which is often manifested on CT by stranding of the peritransplant fat. Chronic postoperative complications include small bowel obstructions, graft pancreatitis secondary to obstruction of the Roux loop, and chronic rejection. CONCLUSION: Knowledge of the radiologic appearance of the normal pancreatic transplant is required before transplant-related complications can be detected.

FDG-PET finding in early-phase Takayasu arteritis.

We report a unique case of early-phase Takayasu arteritis in which the vessels demonstrated accumulation of [18F]fluorodeoxyglucose (FDG) on PET scanning. This observation suggests the possible use of FDG-PET for the diagnosis of vasculitis. Early diagnosis of Takayasu arteritis may permit early treatment and possibly could prevent progression to the occlusive or pulseless phase of this disease.

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.

Unenhanced helical computerized tomography for the evaluation of patients with acute flank pain.

PURPOSE: We determined the value of unenhanced helical computerized tomography (CT) in the diagnosis of acute flank pain in 105 patients evaluated for suspected stone disease. MATERIALS AND METHODS: Noncontrasted spiral CT was done in 105 consecutive patients seen in our emergency department to evaluate acute flank pain. All CT studies were reviewed for the presence of ureteral or renal calculi, perinephric or periureteral stranding, presence and degree of pelvicalicectasis or other radiological findings. If necessary, an excretory urogram was performed to confirm the presence or absence of urinary stones. Patients were followed to determine clinical outcome including the need for urological intervention. RESULTS: Of the 49 patients determined to have stones 24 (49%) had spontaneous stone passage, 10 (20%) had improved symptoms without documented stone passage and 14 (29%) required surgical intervention. In 29 of 51 patients (57%) with negative CT readings for stone disease a diagnosis was established by other intra-abdominal findings. In 21 patients (41%) no clinical diagnosis could be established, and 1 scan in a patient with a distal ureteral calculus was interpreted as falsely positive. These findings yielded a sensitivity of 98%, specificity 98% and overall accuracy 96% for diagnosing ureteral stones. CONCLUSIONS: Despite the limitations of helical CT in evaluating renal function and nonobstructing ureteral calculi, noncontrasted CT is a sensitive imaging modality for the detection of urinary tract calculi and obstruction. The majority of our patients required no further imaging to determine the need for urological intervention. At our institution spiral CT has become the standard method to evaluate patients with acute flank pain leading to more rapid turnover in the emergency department at similar or even reduced cost to conventional excretory urography.

Vesical endometriosis: report of two cases and review of the literature.

Endometriosis is a common gynecologic disease in which endometrial tissue is deposited outside the normal confines of the uterine cavity. In rare instances, endometriosis involves the urinary tract, with the bladder the most frequent organ affected. Classic presenting symptoms include cyclic irritative voiding symptoms and suprapubic discomfort with or without hematuria. Both medical and surgical management have been advocated, but surgical extirpation is probably more efficacious. Two cases of endometriosis involving the the bladder are presented and contrasted in terms of pathophysiology. Contemporary management of this condition is reviewed, and guidelines for diagnosis and treatment are proposed.

Treatment of adverse reactions to radiographic contrast media in adults.

Prompt recognition and treatment can be invaluable in blunting an adverse response of a patient to radiographic contrast material and may prevent a reaction from becoming severe or even life-threatening. Radiologists and their staff should review treatment procedures regularly (at least annually) so that each staff in attendance can accomplish his or her role efficiently. Knowledge, training, and preparation are crucial in guaranteeing appropriate and aggressive therapy in the event of an adverse contrast-related event.

Use of time during body computed tomography scanning in a tertiary care teaching hospital: focus on patient throughput.

RATIONALE AND OBJECTIVES: To control costs, it is increasingly important to make efficient use of imaging technology. We sought to determine and analyze the time required to complete each step of a body computed tomography (CT) scan, focusing on factors that influence patient throughput. METHODS: Over 4 weeks, we prospectively monitored the time required for each step of a body CT scan (i.e., image time, check time, and clear time). Covariate data were collected by patient status: outpatient, inpatient, emergency department (ED), and intensive care unit (ICU); work shift; and radiologist training level (junior resident, senior resident, fellow, and attending). Technologists also predicted whether repeat images would be requested by the radiologist. RESULTS: Three hundred eighty CT examinations were studied: 277 for outpatients, 90 for inpatients, 9 for ED patients, and 4 for ICU patients. The mean total examination time was 44.7 min (mean image time = 33.1 min, mean review time = 8.2 min, and mean clear time = 3.4 min), which did not differ significantly with patient status. A second opinion was sought from a consultant radiologist on the scans of 44 patients. Consultation was requested significantly more frequently (1) by junior residents than by senior residents or fellows and (2) for ED and ICU patients (22% and 50%, respectively) than in outpatients and inpatients (10% and 14%, respectively). Repeat images were obtained from 75 patients, and this was not significantly related to patient status, scan type, or radiologist training level. When the technologist predicted that no repeat images were needed, this prediction agreed with the radiologist in 86% of the cases. When the technologist predicted that repeat images were necessary, this prediction agreed with the radiologist in 56% of the cases. CONCLUSION: Reviewing scans before the patient leaves the CT suite adds considerably to the total time required to complete a scan, particularly if junior residents review scans. If technologists obtain repeat images at their discretion, time would be saved.