Imaging of nontraumatic hemorrhagic hepatic lesions.

Spontaneous hepatic bleeding is a rare condition. In the absence of trauma or anticoagulant therapy, hepatic hemorrhage may be due to underlying liver disease. The most common causes of nontraumatic hepatic hemorrhage are hepatocellular carcinoma and hepatic adenoma. Such hemorrhage can also occur in patients with other liver tumors, such as focal nodular hyperplasia, hemangiomas, and metastases. Other conditions associated with this entity include HELLP syndrome, amyloidosis, and miscellaneous causes. Imaging plays a significant role in the diagnosis and management of this potentially lethal entity. In the appropriate clinical setting, the diagnosis of a hemorrhagic liver lesion is suggested when a hyperechoic mass or a mass with hyperechoic areas is seen at ultrasonography, a hyperattenuating mass is seen at computed tomography (CT), or a mass with high-signal-intensity areas is seen at T1-weighted magnetic resonance (MR) imaging. The signal intensity of blood can be increased or decreased on MR images depending on when the hemorrhage is imaged. The presence and extent of commonly associated subcapsular hematomas and hemoperitoneum can be easily ascertained with CT. During the first 24-72 hours, acute hematomas are hyperattenuating on nonenhanced CT scans; later, they decrease in attenuation and sometimes develop a pseudocapsule.

Genitourinary tract gas: imaging evaluation.

Gas-forming infections of the genitourinary tract may manifest as life-threatening conditions, often requiring aggressive medical and surgical management. Accurate interpretation of the radiologic studies is essential for early and accurate diagnosis of gas within the renal parenchyma or collecting system, bladder, uterus, and scrotum. Three distinct entities are associated with renal or perirenal gas: emphysematous pyelonephritis, emphysematous pyelitis, and gas-forming perirenal abscess. Gas in the bladder may occur secondary to emphysematous cystitis or a vesicoenteric fistula and must be differentiated from air introduced by means of instrumentation. Uterine gas usually indicates an underlying infection or a neoplasm. Gas in the scrotum is most commonly due to an infectious process or bowel herniation into the scrotal sac. Before institution of a specific therapeutic regimen, an effort should be made to establish the exact location of gas in the genitourinary tract. Plain radiography, including tomography, and ultrasonography are useful screening modalities. Although in some cases urography, barium enema studies, and other contrast material-enhanced studies enable a diagnosis to be made, in many patients computed tomography is the definitive diagnostic technique.

Percutaneous sclerotherapy of lymphoceles related to renal transplantation.

PURPOSE: To determine the advantages of using transcatheter sclerotherapy to treat renal allograft-related lymphoceles. MATERIALS AND METHODS: Eighteen patients first seen with symptomatic lymphoceles secondary to renal transplantation were treated with povidone-iodine percutaneous sclerotherapy. Percutaneous catheters were place by means of sonographic, computed tomographic, or combined fluoroscopic and sonographic guidance. Sclerotherapy was initiated while patients were in the hospital, and the patients then instilled povidone-iodine twice a day at home. RESULTS: One patient had an inadequate trial period of therapy and was not included in the analysis. Seventeen lymphoceles were adequately sclerosed. Average length of treatment was 35 days. Three lymphoceles recurred and were effectively treated percutaneously. Follow-up studies showed no recurrence 1 month to 2 years after completion of therapy. No patient needed surgery for lymphocele repair. CONCLUSION: Because of its safety and efficacy, percutaneous transcatheter sclerotherapy with povidone-iodine should be the treatment of choice in patients with lymphoceles that develop after renal transplantation.

Fournier's gangrene: CT findings.

Fournier's gangrene is an uncommon gas-forming infection of the scrotum which if not recognized early and treated appropriately may be fatal. In three patients recently seen at our institution, computed tomography (CT) was instrumental in establishing the correct diagnosis and determining the extent of the infectious process prior to surgery. The imaging findings at CT and its differential diagnosis are illustrated. A brief review of the current theories of pathogenesis of this interesting entity is presented.

Diagnosis of bronchial rupture with MR imaging.

Tracheobronchial rupture is a serious injury occurring in approximately 1.5% of cases of major chest trauma. This injury is associated with significant mortality and morbidity and may be difficult to recognize both clinically and radiologically. Radiologic signs are mostly nonspecific, with pneumothorax and pneumomediastinum being the most common. A high level of suspicion is required to make the diagnosis. Computed tomography (CT) can be helpful; however, it provides only indirect evidence for the diagnosis. This report describes a case of complete transection of the right main bronchus, suspected at plain radiography and CT and clearly shown on magnetic resonance (MR) images. MR imaging, with its multiplanar capabilities, can be helpful in defining the location and extent of injury and in diagnosing injury not suspected or clearly demonstrated with other imaging modalities.

Staging of renal carcinoma using magnetic resonance imaging at 1.5 Tesla.

The preoperative magnetic resonance imaging (MRI) studies of 31 patients with surgically proven renal cell carcinomas obtained with a 1.5 Tesla unit were retrospectively reviewed to assess the accuracy of MRI for staging of tumor. According to the Robson classification 12 patients were found at surgery to have Stage I renal carcinoma, three patients had Stage II, ten had Stage IIIA, one had Stage IIIB, two had Stage IIIC, one had Stage IVA, and two had Stage IVB disease. Twenty-five (81%) of 31 patients were staged correctly by MRI. Clearly MRI showed venous tumor extension without the need for intravenous contrast administration. Also, MRI had a negative predictive value of 95%, and a positive predictive value of 100% for the evaluation of inferior vena cava tumor thrombus. At 1.5 Tesla MRI is an excellent staging modality in the preoperative evaluation of renal carcinoma. It is especially recommended in patients with equivocal computed tomography findings and in all patients with contraindications to the intravenous use of iodinated contrast material.

Radiation-associated sarcoma: a review of 23 patients with postradiation sarcoma over a 50-year period.

Between 1934 and 1983, 23 patients with well-documented diagnosis of radiation-associated sarcoma (RAS) were seen at the University of Michigan Medical Center. The median latent period from irradiation to diagnosis of RAS was 13 years with a minimum latent period of 3 and a maximum of 34 years. All sarcomas originated in previously normal tissues within the irradiated field. Pathology slides available in all patients were reviewed by the same pathologist for the purpose of the study, and the diagnosis of sarcoma was confirmed histologically. There were five bone sarcomas and 18 soft tissue sarcomas. Thirteen patients developed radiation-associated sarcoma following megavoltage treatment with a minimum total radiation dose of 25 Gy in 2 1/2 weeks. The other 10 patients received orthovoltage and/or brachytherapy irradiation alone or combined with external beam radiation. In this group, the radiation doses ranged from 25 Gy to 72 Gy except for one patient who received 8 Gy delivered by orthovoltage irradiation as treatment of knee arthritis. Four patients were originally treated for benign conditions. All the other patients (n = 19) received radiation therapy for a variety of primary malignancies including carcinoma of the cervix (n = 4), brain gliomas (n = 13), Wilm's tumors (n = 2) and retinoblastomas (n = 2), among others.

The detection of adrenal tumors and hyperplasia in patients with primary aldosteronism: comparison of scintigraphy, CT, and MR imaging.

We retrospectively reviewed the imaging studies in 17 proved cases of primary aldosteronism to determine the value of the procedures used to detect adrenal tumors or adrenal hyperplasia. The procedures included CT with 3-, 5-, and/or 10-mm-thick sections (17 patients), 131I-6 beta-iodomethyl-19-norcholesterol (NP-59) scintigraphy (16 patients), and MR imaging (six patients). Proof of the adrenal abnormality was established in cases of tumor (seven adenomas, one carcinoma) by surgery and in cases of adrenal hyperplasia by surgery (three cases); venous sampling (three cases); or combined clinical, biochemical, and imaging data (three cases). Both CT and scintigraphy detected six of the seven adenomas and the adrenal carcinoma (88%). Regarding hyperplasia, CT was correct in five of six and scintigraphy was correct in two of four cases proved by surgery or venous sampling. CT and NP-59 were concordant and suggested the diagnosis of hyperplasia in the remaining three cases without surgical or venous sampling proof. MR detected both cases of adenoma in which it was performed and showed evidence of hyperplasia in one of the four cases of hyperplasia in which it was performed. Although the number of patients in this series is too small to have much statistical power, these results suggest that CT and NP-59 scintigraphy are equivalent in the detection of adrenal abnormalities in patients with primary aldosteronism. The value of MR in the detection of small adrenal contour abnormalities was limited by slice thickness capabilities.

Fluoroscopically guided retrograde brush biopsy in the diagnosis of transitional cell carcinoma of the upper urinary tract: results in 45 patients.

This is a retrospective review of 45 patients suspected of having transitional cell carcinoma of the upper urinary tract who underwent fluoroscopically guided retrograde brush biopsy at our institution during a recent 3-year period. All patients evaluated had an abnormal IV urogram or retrograde pyelogram in which the diagnosis of transitional cell carcinoma of the kidney or ureter was suspected or could not be excluded. The results of the brush biopsy were compared with the final diagnosis established at surgery or through clinical and surgical follow-up. Results of the biopsies were classified into five categories: (I) normal transitional epithelium (16 patients), (II) atypical cells (eight patients), (III) dysplastic cells (two patients), (IV) suspicious for malignancy (four patients), and (V) conclusive evidence of malignancy (eight patients). In four additional patients, other miscellaneous diagnoses were made, and in three others the procedure was nondiagnostic. Brush biopsies interpreted as Categories III, IV, and V had a positive predictive value of 100% (14/14) for the diagnosis of transitional cell carcinoma, and biopsies showing atypical cells (Category II) had a positive predictive value of 75% (6/8). Tabulating all diagnostic categories except for normal as a positive diagnosis, the procedure had a sensitivity of 91%, a specificity of 88%, and an accuracy of 89%. No significant complications were encountered. This experience suggests that brush biopsy is a valuable technique in patients suspected of having transitional cell carcinoma.

Interactive, mathematical, and sequential consultative methods in diagnosing renal masses on excretory urograms.

Using the clinical setting of diagnosing renal masses on excretory urograms, we compared the diagnostic efficacy and costs resulting from different consultative methods. These included face-to-face interactive consultation, mathematical combination of a fixed number of radiologists' confidence judgments, and computerized sequential decision making. This last method mathematically combines a variable number of individual judgments into an aggregate diagnosis based on diagnostic certainty. Six radiologists interpreted 42 proven urograms individually, with face-to-face consultation for selected cases, and interactively in groups of three. Individual diagnostic probability estimations were mathematically combined for the mathematical and sequential models. All models of consultation resulted in both higher diagnostic accuracy and lower costs than individual radiologists interpreting urograms alone. While the sequential model provided the highest diagnostic efficacy, it was only slightly more accurate than the other models tested. Radiologists interactively consulting on cases they considered difficult was the least costly method, approximating the projected costs of sequential decision making. Interactive consultation among radiologists is a cost-effective practice; sequential decision-making is a promising technique for improving diagnostic efficacy and reducing costs, and further evaluation is warranted.

Therapeutic angioinfarction of renal carcinoma: CT follow-up.

Computed tomographic findings in nine patients after renal tumor embolization are reported. All tumors were ablated using absolute alcohol, Gelfoam particles, and occlusion coils. A rim of peripheral enhancement surrounding a central low density area presumed to represent the necrotic infarcted tumor was a constant CT appearance. Intratumoral gas was seen in three patients, persisting for up to 6 months, with eventual resolution. Mild postinfarction syndrome was experienced in all patients. The exact role of preoperative or palliative renal embolization is still controversial, but if the procedure is performed, the natural course of the neoplasm can be best evaluated and followed by serial CT scans.

Comparison of MR imaging and CT in the evaluation of renal masses.

The present status of magnetic resonance imaging (MRI) in the evaluation of renal masses, especially as compared to computed tomography (CT) is discussed based on our experience and on a review of the literature. It is already apparent that simple renal cysts, hemorrhagic cysts, and fatty renal masses are well demonstrated by MRI. However, other modalities, and particularly CT, have similar degrees of accuracy, are more widely available, and are less expensive. So, currently, MRI has not been proven to be an optional screening method for detection of renal masses. At present, the major clinical uses of MRI are (1) the staging of renal carcinoma, in which MRI appears slightly superior to CT, (2) in patients with known contraindications to the use of iodinated contrast medium, (3) in patients with suspected renal carcinomas in which results from other imaging modalities are atypical or indeterminate, and (4) when sagittal or coronal imaging is desirable.

Anastomosed ureters: fluoroscopically guided transconduit retrograde catheterization.

Fluoroscopically guided, transconduit retrograde catheterization of ureters that have been diverted to a bowel conduit is often feasible in patients with patient ureteroenteral anastomoses who might otherwise require a percutaneous nephrostomy (PCN) for reasons other than high-grade anastomotic obstruction. This procedure was attempted on 14 occasions and successfully accomplished on 12. In 11 of these cases, retrograde catheterization obviated PCN to provide renal drainage for a partially obstructing ureteral stricture or obstructing renal calculi, to remove ureteral calculi, or to insert a new ureteral stent after an unsuccessful attempt to exchange an existing occluded retrograde ureteral stent. The procedure also obviated Whitaker testing. On one occasion the retrograde procedure greatly facilitated subsequent PCN in an obese patient with faintly opaque calyceal calculi. These procedures were accomplished with standard angiographic equipment and, in many instances, Teflon sheaths in the bowel conduit to stabilize catheters and guide wires. No complications were encountered. The two patients whose ureters could not be catheterized in retrograde fashion subsequently required PCN.

Fluoroscopically guided pyeloureteral interventions by using a perurethral transvesical approach.

Using a perurethral transvesical approach, we attempted a total of 180 varied pyeloureteral uroradiologic interventional procedures during a 20-month period; 168 were successfully accomplished (93% success rate). We used standard interventional equipment, fluoroscopy, and (for access to the upper urinary tract) ureteral catheters that had been partially or completely inserted at cystoscopy by urologists. The successful procedures included insertion of double-pigtail ureteral stents (42 procedures), insertion of single-pigtail ureteral stents (47), advancement of arrested or incompletely inserted retrograde ureteral catheters (42), urothelial biopsy (30), balloon dilatation of ureteral strictures (three), retrograde cannulation of ureteropelvic junction obstructions that could not be negotiated in a percutaneous antegrade fashion (three), and ureteral stone extraction (one). The method was unsuccessful in 12 patients. Failures were due to caudal migration of a ureteral catheter into the bladder in eight patients and to an inability to advance a guidewire beyond an area of ureteral obstruction or perforation in four. Although most commonly used as an adjunct to extracorporeal shock-wave lithotripsy of renal and proximal ureteral calculi, the perurethral approach was extremely valuable for a wide variety of other indications. Significant complications, encountered in 5% of the procedures, included urosepsis (two), ureteral perforations (five), and cannulation of a false ureteral lumen (two). These problems resolved without sequelae with conservative management. The perurethral transvesical approach represents a relatively simple, safe, and expeditious interventional uroradiologic method. It frequently obviated other more invasive interventions such as percutaneous nephrostomy, ureteroscopy, or surgery.

The development of steinstrassen after ESWL: frequency, natural history, and radiologic management.

Stone fragments that develop after extracorporeal shock-wave lithotripsy (ESWL) may lodge within the ureter. This column of fragments is referred to as a "steinstrasse" (plural, steinstrassen). We evaluated the first 1000 patients treated with ESWL at our institution to determine the frequency of steinstrasse formation, the clinical course of patients with steinstrassen, and the types of intervention, if any, required. Steinstrassen were seen in 20% of 1000 patients treated with ESWL. In 65% of the patients studied, the steinstrassen passed spontaneously. Of the remaining patients, all but 3% required treatment for ureteral obstruction. Seventy-five percent were treated urologically (ureteroscopy, ureteral catheterization), but 25% required radiologically directed intervention, either percutaneous nephrostomy or fluoroscopically monitored retrograde ureteral catheter/stent placement. Twenty-seven percent of our patients with persistent steinstrassen had silent obstruction. In view of the insidious manner in which kidney function may be jeopardized by steinstrassen, they should be managed with great circumspection. Radiologists dealing with steinstrassen should be skillful in both antegrade and retrograde methods of urinary tract intervention.

Balloon catheter dilation of ureteroenteric strictures: long-term results.

Balloon catheter dilation of benign ureteroenteric anastomotic strictures has been proposed as an alternative to either surgical revision or chronic ureteral stenting, with moderately successful short-term results reported by several groups in a limited number of patients. However, the authors' experience with 29 patients exhibiting 37 benign ureteroenteric strictures treated over the past 7 years revealed that in the majority of cases (23 patients, 26 strictures [70%]), strictures recurred within 6 months of balloon catheter dilation/ureteral stent therapy. Furthermore, of the 11 strictures that appeared to have been successfully dilated at a follow-up interval of 6 months, five restenosed within 1 year. Therefore, only six of 37 (16%) ureteroenteric stricture dilations could be considered successful when viewed at least 1 year after interventional therapy. Furthermore, repeat dilations have often been required to maintain ureteral patency in these patients.