Omental infarct: CT imaging features.

BACKGROUND: The aim of this study is to describe contrast-enhanced computed tomographic (CT) features of acute omental infarction and to study the evolutionary changes on follow-up CT imaging. METHODS: Fifteen cases of omental infarction were evaluated for their initial CT imaging features. The imaging features evaluated included size of the fatty lesion, location, peripheral rim, and relation to colon. CT findings were correlated with etiology, clinical presentation, and leukocytosis. Follow-up CT images were available in eight patients and the imaging features were studied. RESULTS: Eight omental infarcts were of unknown etiology and seven were secondary to abdominal surgery. In 53% of patients (eight of 15), the location of the omental infarct was in the right lower, mid, or upper quadrants. These eight right-side infarcts occurred in six patients with primary omental infarcts. In 13 of 14 patients who underwent CT within 15 days of onset of omental infarct, the margin of the lesion was ill defined. Primary omental (n = 8) infarcts were seen in younger patients (p = 0.02) and were larger on CT (p = 0.02) compared with secondary omental infarcts. CT findings evolved from an ill-defined, heterogeneous fat-density lesion to a well-defined, heterogeneous fat-density lesion with a peripheral hyperdense rim in all six secondary omental infarctions for which acute stage and follow-up CT images were available for interpretation. CONCLUSION: There is a significant difference in the age distribution and CT findings in terms of size of the omental infarction between primary and secondary etiologies. On follow-up CT, secondary omental infarcts progressively shrank and developed a well-defined, hyperdense rim around a fatty core.

Radiofrequency ablation of renal cell carcinoma.

Small renal cell carcinomas of less than 4 cm diameter have been detected increasingly in asymptomatic patients because of the widespread use of cross-sectional imaging. Radical or partial nephrectomy is generally considered the reference for the treatment of a solitary renal cell carcinoma. However, for those patients who are not candidates for surgery, minimally invasive procedures may be desirable. Although percutaneous radiofrequency ablation for the treatment of renal cell carcinoma is a recent innovation, the results of preliminary clinical series and animal studies are encouraging, and show it to be technically feasible with minimal morbidity. In this article, we review the technique, indications, imaging findings, as well as the results of clinical and animal studies of radiofrequency ablation for the treatment of renal cell carcinoma.

Predictive value of benign percutaneous adrenal biopsies in oncology patients.

PURPOSE: Percutaneous CT guided biopsy is accepted as a safe procedure for the diagnosis of indeterminate adrenal masses in oncologic patients. The purpose of this study was to evaluate the accuracy of a 'negative for tumour' adrenal biopsy in the oncologic patient population by assessing subsequent outcome including clinical course, size and imaging characteristics of the adrenal lesions on follow-up imaging studies and pathological findings at re-biopsy or following adrenal mass resection. MATERIALS AND METHODS: Retrospective analysis of 225 oncological patients (FM, 128;87; age range 33-87 years, mean age 66 years) who had undergone CT guided biopsies of an adrenal mass over a 5-year period was performed. Those patients with a report consistent with 'negative for malignancy' were evaluated by reviewing the medical records for patient demographics, primary malignancy, histology of adrenal tumour, subsequent surgical interventions, repeat adrenal biopsy under image guidance, by open surgery or at autopsy, subsequent abdominal imaging in which the adrenal gland was imaged, and long-term outcome including hospital admissions, or death. RESULTS: Of the 225 CT-guided adrenal biopsies performed, 41 (18%) were negative for neoplasm. The primary neoplasm in these 41 patients included lung cancer (n=32), breast (n=5), renal cell carcinoma (n=2), bladder (n=1), and prostate (n=1). The size of the adrenal lesions ranged from 2.8-5 cm. Of the 41 biopsies, which were negative for tumour; 10 were identified as adenomas and the rest showed benign adrenal cortical cells or hyperplasia on cytopathology and histopathology. Repeat biopsies were obtained in 13/41 (31%) patients; whereas 2/41 (5%) had their adrenal gland analyzed on post mortem examination. None of these 15 repeat evaluations yielded tumour. CONCLUSION: In oncological patients, pathological analysis of tissue samples obtained by CT-guided percutaneous biopsy, suggesting benign aetiology, is reliable and predicts a benign course on long-term follow-up. A negative or benign pathology result for a CT guided percutaneous adrenal biopsy can be regarded as a true negative evaluation in oncological patients with no necessity to repeat the biopsy.

Tunneled peritoneal catheter placement under sonographic and fluoroscopic guidance in the palliative treatment of malignant ascites.

OBJECTIVE: We present a treatment for recurrent, symptomatic ascites in patients with malignant disease. This report summarizes our experience with percutaneous tunneled peritoneal catheters in 24 patients. SUBJECTS AND METHODS: Of the 40 consecutive patients who presented with at least four therapeutic paracenteses in a 4-week period, 24 patients underwent the percutaneous tunneled procedure. All had malignant ascites. RESULTS: All 24 patients had successful insertion of a permanent tunneled peritoneal drainage catheter. Eighteen were outpatients and six were inpatients. All patients were relieved of their clinical symptoms, including abdominal distention and dyspnea, and were relieved of lower extremity discomfort. The mean life span after catheter placement was 7.2 weeks. Twenty (83%) of the 24 patients were treated at home with their catheters in place. Three patients experienced minor complications from bacterial peritonitis, which responded to antibiotics. One patient had to have his catheter removed. CONCLUSION: Percutaneous placement of specialized tunneled catheters appears to be a viable and safe technique in patients who have symptomatic ascites that require frequent therapeutic paracentesis for relief of symptoms.

Nonvascular interventional procedures: analysis of a 10-year database containing more than 21,000 cases.

PURPOSE: To analyze all procedures performed during 10 years in a nonvascular interventional practice. MATERIALS AND METHODS: Date, organ location, and type of all 21,324 procedures performed between October 1990 and September 2000 were recorded in a database; also included were patient age and inpatient or outpatient status. Because genitourinary procedures were not included during the first 4 years, nephrostomies were added retrospectively. Yearly interventional caseload was compared with the department caseload and the assignment of new medical record numbers. Trends in individual procedure location and type were analyzed, as well as patient age, inpatient status, daily caseloads, and day of the week when the procedure was performed. RESULTS: Caseloads have increased 10.8% per year, exceeding increases in radiology department and hospital activity. Abdomen, outside of a specific organ, was the most common location; catheter deployment was the most common procedure. Abscess drainage, placement of chest tubes, and nephrostomies have increased, but biliary drainages have decreased. Inpatients outnumbered outpatients in all years except 1995, but the trend was toward an increase in the proportion of outpatients. The average patient was 59.6 years old, with average age diminishing. Friday was the busiest day, but weekend procedures have increased. CONCLUSION: Nonvascular interventional procedures have increased, with more currently being performed on weekends.

Transvaginal interventional procedures: aspiration, biopsy, and catheter drainage.

Transvaginal ultrasonographically (US) guided procedures are simple and safe and often represent the only means of access to pelvic disease. Aspiration of cystic pelvic masses and core biopsy of solid pelvic masses can be easily performed by using the transvaginal route, an endoluminal US transducer, and a needle guide. Because of concerns about false-negative diagnosis and potential tumor seeding with biopsy of primary ovarian cystic lesions, the indications for transvaginal aspiration and biopsy of ovarian and adnexal lesions are predominantly therapeutic. Similarly, using an endoluminal probe with modification of the guide, one can also perform safe and effective trocar catheter drainage of pelvic abscesses via the transvaginal route. The transvaginal route is ideally suited to pelvic abscess drainage because of the proximity of the vaginal fornices to most pelvic fluid collections. The transvaginal route has the disadvantage of being semisterile; because of the risk of superinfecting previously noninfected pelvic pathologic conditions, the transvaginal approach should be used only for solid lesions or cystic lesions that can be completely aspirated. Familiarity with the transvaginal route of access is crucial for adequate treatment of many gynecologic and nongynecologic pelvic pathologic conditions.

Complications after pancreatoduodenectomy: imaging and imaging-guided interventional procedures.

Over the past decade, performance of the Whipple procedure, or pancreatoduodenectomy, to treat both malignant and benign disease has increased. This increase is in large part due to the decreasing perioperative mortality rate, which is down from historic highs of 25% to the 1.0%--1.5% now achieved in large centers. Although advances in surgical management have improved the outlook for patients undergoing pancreatoduodenectomy, the improving mortality rate is also in part attributed to improvements over the past 2 decades in cross-sectional imaging and imaging-guided interventional procedures. Although the mortality rates have improved, the morbidity, or rate of complications, has remained relatively constant. Contributions by radiologists in both diagnosis and treatment of complications are crucial in certain patients with postpancreatoduodenectomy abdominal abscesses, bilomas, liver abscess, and biliary obstruction. Familiarity with normal variations in the postoperative appearance of the upper abdomen, awareness of pitfalls in interpretation, and knowledge of the available imaging-guided interventions will facilitate recognition of postpancreatoduodenectomy complications and allow prompt triage of patients to imaging-guided interventions.

Radio-frequency ablation of renal cell carcinoma: early clinical experience.

PURPOSE: To report the authors' early experience with radio-frequency (RF) ablation of renal cell carcinoma. MATERIALS AND METHODS: Twenty-four percutaneous RF ablation treatments for nine tumors were performed in eight patients with renal cell carcinoma. Indications included coexistent morbidity, previous surgery, or solitary kidney in patients with a life expectancy shorter than 10 years. Smaller (3 cm) and/or central lesions (n = 6) were treated with cluster or multiple electrodes. Patients returned for a second treatment when follow-up imaging depicted tumor enhancement. Follow-up imaging was performed at 1 and 3 months and then at 6-month intervals, with a mean follow-up of 10.3 months. Seven patients were alive at least 6 months after their initial treatment. RESULTS: All five exophytic tumors were free of enhancement. One of three central tumors was free of enhancement. One tumor had both central and exophytic components and was free of enhancement. Three tumors were 3 cm or smaller and free of enhancement. Of the six tumors larger than 3 cm, four were free of enhancement. CONCLUSION: Percutaneous RF ablation is a promising treatment for select patients with renal cell carcinoma. The ultimate role of this modality will continue to evolve and warrants further study.

CT-Guided transgluteal drainage of deep pelvic abscesses in children: selective use as an alternative to transrectal drainage.

OBJECTIVE: The transgluteal approach to abscess drainage through the greater sciatic foramen has been described in adults, but this route has not been as extensively studied in children. We performed CT-guided transgluteal percutaneous abscess drainage in seven children and assessed the results of drainage and catheter tolerance. CONCLUSION: Transgluteal catheters are well tolerated by children, and the transgluteal route is an effective approach to selected pelvic abscesses in children.

US-guided thoracentesis: requirement for postprocedure chest radiography in patients who receive mechanical ventilation versus patients who breathe spontaneously.

PURPOSE: To identify a population of patients who may not need chest radiography after diagnostic thoracentesis by assessing and comparing the pneumothorax rates in patients with mechanical ventilation (intubation) versus spontaneously breathing patients (no intubation). MATERIALS AND METHODS: A retrospective review of all radiographs, clinical records, and ultrasound (US) scans obtained in 434 patients who underwent US-guided thoracentesis was performed. Three hundred forty-two patients were not intubated and 92 were intubated. Nine patients were excluded because of preexisting pneumothorax. The size of the effusion, the needle size used, and whether a pneumothorax occurred after the procedure were determined. RESULTS: Results demonstrated that only 10 pneumothoraces occurred (six in intubated and four in nonintubated patients). None of the nonintubated patients with pneumothorax and two of the six intubated patients with pneumothorax needed chest tubes. The difference in the pneumothorax rate between intubated and nonintubated patients was statistically significant (P < .01). CONCLUSION: Spontaneously breathing patients who undergo diagnostic thoracentesis do not need postprocedure chest radiography.

Gadolinium-DTPA enhanced echoplanar MR imaging of the liver: preliminary observations.

This study describes our preliminary experience with dynamic gadopentetate dimeglumine enhanced echoplaner MR imaging (EPI) in fifteen patients with focal liver lesions. Lesion diagnosis was established by histology (n = 3) or typical imaging characteristics (exclusive of the EPI study) combined with clinical follow up (n = 12). Dynamic gadopentetate dimeglumine (0.1 mmol/kg) enhanced MR imaging was performed on a commercially available 1.5 T EPI equipped MR system using a single-excitation fat-suppressed inversion recovery pulse sequence. The choice of an IR sequence allowed nulling of the lesion signal by varying T1 prior to enhancement creating the optimal conditions for qualitative inspection of the enhancement profile. Intershot delay (defined as TR) ranged from 1-5s. Image analysis was performed qualitatively by two radiologists. Benign and malignant lesions displayed temporal enhancement profiles compatible with characteristic findings expected with conventional imaging modalities. Further refinements in our technique and expanded system capabilities will allow dynamic imaging of the entire liver with improved temporal resolution over conventional sequences.

The CT small bowel faeces sign: description and clinical significance.

OBJECTIVE: To describe a new CT sign of the GI tract: the small bowel faeces sign, and discuss its significance. METHODS: The small bowel faeces sign consists of gas bubbles mixed with particulate matter in dilated segments of small bowel. This was a retrospective study of 22 patients demonstrating this sign from 1989 to 1993. Final diagnosis was established by surgical, medical or laboratory findings. To determine the prevalence of the sign, the CT examination of 120 consecutive separate control patients were evaluated. RESULTS: All 22 of the patients demonstrating this sign required hospitalization with surgical or medical intervention. Eighteen of 22 had mechanical small bowel obstruction. The remaining four patients had other abnormalities of small bowel to account for the finding on CT. Twelve of the 22 patients were treated with surgery and the remaining 10 patients were treated with nasogastric tubes (n = 6) or other medical therapy (n = 4). None of the 120 control patients demonstrated the sign. CONCLUSION: The presence of gas and particulate material resembling faeces in a dilated segment of small bowel on CT is abnormal. Most (18/22; 82%) patients with this sign had small bowel obstruction.