Three-dimensional ultrasound and magnetic resonance imaging of pelvic anatomy: potential for complications from minimally invasive procedures.

OBJECTIVE: Several new minimally invasive therapies have recently been popularized for both malignant and benign prostate disorders, including interstitial implantation of radioactive seeds and high-radiofrequency wires, cryoablation, transurethral thermotherapy, and laser prostatectomy. Complications can be incurred during the various procedures, often as a result of injury to adjacent anatomic structures. Some of the complications are inadvertent, whereas others are inherent in the particular treatment process. We hope to increase awareness and understanding of some of the potential complications. METHODS AND MATERIALS: Magnetic resonance (MR) and three-dimensional transrectal ultrasonography (TRUS) imaging were utilized to illustrate the relevant pelvic anatomy in, respectively, a healthy volunteer and four patients undergoing evaluation for prostate symptoms. In addition, data from the Visible Human dataset (the Visible Human Project is part of the National Library of Medicine 1986 Long-Range Plan) were used. RESULTS: The potential complications relating to urinary sphincter and anal sphincter control, sexual function, pelvic musculature, and pelvic nerve physiology could be explained on the basis of the MR and TRUS findings using cryoablation for illustrative purposes. CONCLUSION: A clear understanding of the relevant anatomy and physiology is essential for the physician to provide patient counseling preoperatively regarding anticipated sequelae and to avoid preventable intraoperative complications related to minimally invasive therapeutic procedures for the prostate.

Percutaneous embolotherapy of lower gastrointestinal hemorrhage.

PURPOSE: To evaluate percutaneous embolotherapy in the treatment of lower gastrointestinal hemorrhage. MATERIALS AND METHODS: Twenty-one patients who underwent attempted percutaneous embolization for acute lower gastrointestinal bleeding between 1982 and 1997 were retrospectively studied. Hemorrhagic sites included jejunum (n = 4), ileum (n = 4), cecum (n = 4), and the remaining colon (n = 9). RESULTS: Embolization was not technically possible in four patients (19%). Hemostasis was achieved in 15 patients (71%) with prolonged hemostasis in 10 (48%). All embolizations distal to the cecum resulted in prolonged hemostasis. Three of four patients with jejunal bleeding had recurrent bleeding after apparent successful embolization. Only one of four cecal embolizations achieved prolonged cessation of bleeding. No ischemic complications were identified. CONCLUSION: Based on these data, it would appear that the risk of bowel ischemia/infarction in the lower gastrointestinal tract may not be as high as has been suggested. Two regions (cecum and proximal jejunum) were associated with poor results, suggesting these areas may not be as responsive to embolotherapy as other sites in the lower gastrointestinal tract.

Intra- and inter-observer variability and reliability of prostate volume measurement via two-dimensional and three-dimensional ultrasound imaging.

We describe the results of a study to evaluate the intra- and inter-observer variability and reliability of prostate volume measurements made from transrectal ultrasound (TRUS) images, using either the (optimal) height-width-length (HWL) method (V = pi/6 HWL) with two-dimensional (2D) TRUS images (obtained as cross-sections of three-dimensional [3D] TRUS images) or manual planimetry of 3D TRUS images (the 3D US method). In this study, eight observers measured 15 prostate images, twice via each method, and an analysis of variance (ANOVA) was performed. This analysis shows that, with the 3D US method, intra-observer prostate volume estimates have 5.1% variability and 99% reliability, and inter-observer estimates have 11.4% variability and 96% reliability. With the HWL method, intra-observer estimates have 15.5% variability and 93% reliability, and inter-observer estimates have 21.9% variability and 87% reliability. Thus, in vivo prostate volume estimates from manual planimetry of 3D TRUS images have much lower variability and higher reliability than HWL estimates from 2D TRUS images.

An expandable intravenous RF coil for arterial wall imaging.

An intravenous (iv) radiofrequency (RF) coil is proposed as a means of obtaining high resolution images of artery wall. The anatomic positioning of peripheral artery/vein pairs was investigated and a phantom mimicking the iliac artery/vein pair was constructed. Imaging results, comparing iv coils with external coils, demonstrated a potential 15- to 20-fold increase in signal-to-noise ratio (SNR) with iv coils. The SNR benefit was measured over a cylindrical volume, adjacent to the coil, and typical of artery position. Prototype expandable iv coils were constructed of Cu-Be loops and introduced via an 8-Fr catheter. The effects of local and remote iv coil tuning were investigated and local tuning was found to provide significant SNR benefits. The in vivo performance of iv RF coils was demonstrated in a porcine animal model. The iv coils were found to be an excellent alternative to intraarterial coils.

Embolization of iliac artery aneurysms following abdominal aortic aneurysm repair with a bifurcated graft.

Six iliac artery aneurysms in four patients were percutaneously embolized. All patients had previous abdominal aortic aneurysm repair using a bifurcation graft with distal anastomoses to external iliac arteries. The iliac aneurysms involved the oversewn common iliac arteries in all patients. Embolizations were performed via an ipsilateral common femoral arterial approach, with metal coil occlusion of aneurysm inflow and outflow. All aneurysms were successfully thrombosed. Follow-up colour flow Doppler examinations showed continued aneurysm thrombosis in all patients. One patient developed post procedure buttock claudication, which improved over time; there was no other procedure related morbidity. In conclusion, we describe a technique for percutaneous embolization of iliac aneurysms following abdominal aortic aneurysm repair with a bifurcated graft. We have demonstrated the safety and efficacy of this approach.

Sonography of intestinal abnormality in the right iliac fossa.

The findings on sonographic examination of intestinal disorders in the right iliac fossa are often nonspecific. We have found the classification system just described useful because it leads to a meaningful differential diagnosis, which may be narrowed on the basis of various distinguishing features. The use of other imaging techniques, imaging-guided aspiration or biopsy, or surgical intervention may be necessary to make the exact diagnosis.

An alternative approach to acute cholecystitis. Percutaneous cholecystostomy and interval laparoscopic cholecystectomy.

BACKGROUND: The mainstay of therapy for acute cholecystitis is cholecystectomy, which has a mortality of 5-30% in high-risk patients such as the elderly or critically ill. An alternative treatment option in patients suffering from acute cholecystitis with contraindications to emergency surgery is percutaneous cholecystostomy (PC) followed by interval laparoscopic cholecystectomy. Percutaneous cholecystostomy yields 10-12% mortality in high-risk patients and is therefore a safe temporizing measure, allowing delayed, elective cholecystectomy when the patient is in better condition for surgery. METHODS: Hospital charts and radiology films were reviewed for all 50 patients who underwent PC for acute cholecystitis between January 1990 and September 1993. Most patients were high risk for emergency cholecystectomy by virtue of their critical illness or underlying medical condition. Twenty-five patients went on to have interval cholecystectomies. We recorded whether they underwent laparoscopic or open cholecystectomy, as elective or emergency procedures, and we recorded direct complications, mortality, and postoperative length of hospital stay. RESULTS: Relief of symptoms occurred within 48 h of PC in 90% of patients, and two patients had complications of PC. Laparoscopic cholecystectomy was attempted in 13 patients and competed in nine. Four patients (31%) required conversion from laparoscopic to open cholecystectomies due to extensive adhesions (3) or bleeding (1). Three patients had direct complications of laparoscopic cholecystectomy. There was no mortality or major bile duct injury. CONCLUSION: Percutaneous cholecystostomy followed by interval laparoscopic cholecystectomy is a safe, minimally invasive approach which can be employed safely in the critically ill patient when contraindications to emergency surgery exist.

Portacaval space anatomy: potential implications for percutaneous portacaval shunts.

PURPOSE: To assess the anatomic feasibility of percutaneous portacaval shunt formation. MATERIALS AND METHODS: One hundred contrast material-enhanced computed tomographic (CT) scans were retrospectively reviewed. The distance and direction from the inferior vena cava (IVC) to the main portal vein (MPV) were measured. Anatomic structures intervening between the IVC and the MPV, and related to the MPV were also noted. RESULTS: The distance between the IVC and the MPV was less than 1 cm in most cases. The direction from the IVC to the upper, middle, and lower thirds of the MPV was predictable and lay within a relatively narrow range. At the middle MPV, there were no intervening structures between the IVC and the MPV in most cases. Intervening structures included the liver at the upper MPV and nodes at the lower MPV. The most common structures related to the MPV included the liver, hepatic artery, and gallbladder (upper MPV); liver, stomach, and pancreas (middle MPV); and pancreas, duodenum, and celiac axis (lower MPV). CONCLUSIONS: These results indicate a short distance and predictable direction between the IVC and MPV. If aberrant vessels and a prominent caudate lobe are excluded, there appears to be a relatively safe cavo-portal route (with respect to neighboring and intervening structures) at the level of the middle MPV. These findings indicate that percutaneous portacaval shunting may be worthy of further experimental study.

Fluoroscopically guided percutaneous gastrostomy: current status.

The authors review the current status of fluoroscopically guided percutaneous gastrostomy (FGPG). The indications for this procedure have been expanded since the technique was first described over a decade ago. Ther are few contraindications to FGPG, although modifications are required in some situations. The procedure involves placing a feeding tube into the stomach by a modified Seldinger technique. According to the literature, most interventionalists do not routinely employ gastropexy. The insertion of gastrojejunostomy feeding tubes rather than gastrostomy feeding tubes to reduce gastroesophageal reflux remains controversial. Complications after FGPG are rare. Feeding tubes inserted in this manner allow satisfactory establishment and maintenance of enteral feeding. The technique compares favourably with other methods of inserting gastrostomy tubes.

Outpatient percutaneous nephrostomy.

PURPOSE: To assess the feasibility of performing percutaneous nephrostomy (PCN) on an outpatient basis in a select group of patients. MATERIALS AND METHODS: In 6 years, 60 PCN procedures were performed in a subgroup of 48 patients (22 men, 26 women) carefully selected from a larger group of 881 nephrostomy procedures in 589 patients. Exclusion criteria included hypertension; untreated urinary tract infection, coagulopathy, and staghorn calculi. Indications were calculus (n = 17), benign stricture (n = 10), and malignant ureteric obstruction (n = 21). RESULTS: There was 100% technical success. Six of 48 patients (12%) were admitted within a week of PCN; there were no cost savings in these patients. Three of these patients (6%) were admitted as a direct consequence of PCN; one had sepsis, one had bleeding, and one was unable to manage the PCN tube. Outpatient treatment saved the cost of hospitalization in 42 patients (88%). CONCLUSION: Outpatient PCN is feasible and safe in carefully selected patients and yields major cost savings because it precludes hospital admission.

Patellar tendinitis: MR imaging features, with suggested pathogenesis and proposed classification.

PURPOSE: To characterize the magnetic resonance (MR) imaging features of patellar tendinitis. MATERIALS AND METHODS: Fifteen patients with a clinical diagnosis of patellar tendinitis underwent gadolinium-enhanced MR imaging of the knee. RESULTS: Grades of patellar abnormality, based on findings in the enthesial region at MR imaging, correlated with signs of increasing fibrovascular repair: grade 1 (n = 4), enhancing area adjacent to patellar apex, with marginal zone of intermediate signal intensity, and a patellar apical chondral-bone avulsion; grade 2 (n = 5), same signs as grade 1 damage but without avulsion; grade 3 (n = 6), homogeneous, nonenhancing area of intermediate signal intensity adjacent to the patellar apex seen on all images. Changes were most obvious posteriorly and involved the central and medial thirds of the tendon. Chronic injury to the medial retinaculum was a common associated finding. CONCLUSION: Patellar tendinitis demonstrates a consistent spectrum of changes at MR imaging that can aid understanding of the origin and treatment of damage.

Radiology reports: how much descriptive detail is enough?

OBJECTIVE: The purpose of our study was to determine whether physicians prefer radiology reports with no description, a brief description, or a detailed description of the radiologic findings. We also examined the effects of various clinical circumstances and physician characteristics (e.g., specialty and number of years in practice) on these preferences. This study, which is limited to commonly encountered scenarios, is concerned solely with the description of imaging findings and not with other aspects of the reports, such as the diagnosis and technique. MATERIALS AND METHODS: A questionnaire was sent to the 100 physicians who most frequently refer patients to our practice for chest radiographs and abdominal sonograms. The questionnaire outlined six clinical scenarios. For each scenario the physician was asked to indicate the preferred radiology report from a set of three reports varying in descriptive detail. RESULTS: Seventy-seven physicians replied. For a normal chest radiograph in a patient without specific chest symptoms, the most popular report format indicated simply that the examination was normal. When there were clinical findings involving the chest or abnormal radiologic findings, the majority of referring physicians desired a description of the findings and the radiologic diagnosis. For abdominal sonograms the majority of physicians favored reports detailing the findings, even when the findings were normal. In all instances the preferences expressed were independent of the academic status, number of years in practice, number of reports read per day, and specialty of the referring physician. CONCLUSION: Our results show that preferences of referring physicians for the extent of description of imaging findings included in radiology reports depend on the clinical circumstances. In the specific clinical scenarios examined, physicians preferred that the report include a brief description of the findings, except for screening chest radiographs, for which "normal examination" was an acceptable report. The referring physicians' preferences regarding the amount of descriptive detail included in the report were independent of their specialty, academic status, and experience.

High resolution endoluminal ultrasonography in the staging of esophageal carcinoma.

Small catheters containing 20 MHz transducers have recently become available for high resolution endoluminal ultrasound. We report our early use of this technique to image and stage esophageal carcinoma. Fifteen patients undergoing high resolution endoluminal ultrasonography for suspected esophageal carcinoma were studied. Twelve of these patients also underwent computed tomography and pathologic correlation was available in seven. Satisfactory esophageal examination was possible in 14 of 15 patients. Of those with pathologic correlation, the depth of tumor invasion was correctly staged by high resolution endoluminal ultrasonography in six of seven patients and by computed tomography in only three of seven patients. Lymph node assessment correlated poorly with pathologic findings for both high resolution endoluminal ultrasound and computed tomography. With the increasing use of preoperative radiation therapy, we believe these early results predict a potential role for high resolution endoluminal ultrasonography in the staging of esophageal carcinoma.

Severity of disease score as a predictor of mortality after caval filter insertion.

PURPOSE: To estimate 30-day mortality after vena caval filter insertion and assess the usefulness of a severity of disease score in predicting postprocedure 30-day survival. PATIENTS AND METHODS: Records of 40 consecutive patients undergoing inferior vena caval filter insertion over a 2 1/2-year period were retrospectively reviewed. A severity of illness score for each patient was calculated based on the weighting system described for the APACHE (Acute Physiology and Chronic Health Evaluation) II system. In addition, 30-day postprocedure survival was determined. RESULTS: Seven patients died within 30 days of the procedure (18%). The use of a severity of disease score of greater than 15 as a predictor of postprocedure 30-day mortality had a sensitivity of 50%, specificity of 97%, positive predictive value of 75%, a negative predictive value of 91.4%, and accuracy of 90%. CONCLUSIONS: The 30-day mortality after caval filter insertion is significant. A severity of disease score is a useful predictor of patients likely to survive following caval filter insertion. On this basis it may be possible to establish criteria for more beneficial use of vena caval filters.

Sonographic assessment of infrarenal inferior vena caval dimensions.

The dimensions of the infrarenal inferior vena cava during quiet respiration, single leg lifting, and breath-holding were assessed using sonography in 156 patients. Sonographic assessment of infrarenal inferior vena caval dimensions was feasible in 69% of patients. Measurements during breath-holding were significantly greater than during quiet respiration (P < 0.001) and leg lifting (P < 0.005), although in approximately one quarter of the patients the mean calculated diameter was greatest during quiet respiration. we conclude that sonographic assessment of infrarenal inferior vena caval dimensions is feasible, but it should be performed during quiet respiration and breath-holding to allow for variation with different respiratory maneuvers.

CT of the liver after cryotherapy of hepatic metastases: imaging findings.

Cryotherapy is the in situ destruction of abnormal tissue using subzero temperatures (Fig. 1). Recent studies have demonstrated the technical feasibility, safety, and effectiveness of hepatic cryotherapy in the treatment of liver tumors [1, 2]. Such treatment can be precisely focused on the tumor, thereby preserving surrounding normal tissue. In addition, because major vessels with flowing blood are protected from cryoablation, tumors adjacent to these vessels can be treated without sacrificing vasculature. Hepatic cryoablation is therefore particularly suitable for patients who do not qualify for surgical resection because of multiple metastases involving both lobes of the liver, or because of lesions close to major blood vessels. After the procedure, CT during arterioportography is of little value in distinguishing cryolesion from malignant tumor (Fig. 2), and CT with IV contrast enhancement is recommended for follow-up. It is important to distinguish CT findings of successful and unsuccessful treatment, treatment complications such as abscess and cholestasis, and recurrent tumor. The purpose of this essay is to illustrate the findings on CT with IV contrast enhancement in various situations, emphasizing features that are useful in making accurate differential diagnosis.

MR imaging of adrenal masses: value of chemical-shift imaging for distinguishing adenomas from other tumors.

OBJECTIVE: CT and conventional MR imaging are helpful in characterizing adrenal tumors, but a specific diagnosis is not achieved for a substantial number of lesions. Chemical-shift imaging relies on the different resonance frequencies of protons in water and triglyceride molecules and therefore may permit a more specific diagnosis of adrenal adenomas, which are known to contain abundant lipid. The purpose of this study was to evaluate the usefulness of chemical-shift MR imaging in the differentiation of adrenal adenomas from other adrenal masses. SUBJECTS AND METHODS: Forty-one adrenal masses (17 nonhyperfunctioning adenomas, two aldosteronomas, six pheochromocytomas, one ganglioneuroma, five adrenal carcinomas, one lymphoma, seven metastases, one case of extramedullary hematopoiesis, and one leiomyosarcoma) suspected clinically or identified by sonography or CT in 38 patients were prospectively evaluated with MR imaging. Pathologic proof of diagnosis was obtained for 28 lesions, and stability on imaging follow-up (mean, 19 months) was accepted as proof of diagnosis of benign adenoma for 13 lesions. In-phase T1-weighted spin-echo sequences (500/20 [TR/TE]) and opposed-phase gradient-echo sequences (142/6.3, flip angle = 90 degrees) of the adrenal regions were applied. Quantitative analysis of signal intensity loss in the adrenal lesions relative to reference tissues (liver, muscle, and spleen) on in-phase and opposed-phase sequences was done to differentiate adenomas from nonadenomas. Region-of-interest signal intensity measurements were obtained in a standard fashion by selection of the largest possible representative sample. RESULTS: Using liver as the reference standard, we found that mean signal intensity ratios were 0.47 (range, 0.23-0.97) for adrenal adenomas and 0.88 (range, 0.65-1.32) for nonadenomas; signal intensity ratios for two adenomas overlapped those of the nonadenomas. Using muscle as the reference standard, we found that mean signal intensity ratios were 0.44 (range, 0.22-0.66) for adrenal adenomas and 0.85 (range, 0.59-1.39) for nonadenomas; signal intensity ratios for two adenomas overlapped those of the nonadenomas. Using spleen as the reference standard, we found that mean signal intensity ratios were 0.45 (range, 0.27-0.73) for adrenal adenomas and 0.97 (range, 0.8-1.18) for nonadenomas, with no overlap. The mean signal intensity ratios were significantly different between adenomas and nonadenomas for all three reference tissues (p < .001). CONCLUSION: Our results show that chemical-shift MR imaging is an important new technique that enables the differentiation of adrenal adenomas from other adrenal masses, reducing the need for biopsy and prolonged imaging follow-up in patients with adrenal tumors.

Peritoneal abscesses due to bowel perforation: effect of extent on outcome after percutaneous drainage.

PURPOSE: To determine the effect of extent of peritoneal contamination in enteric abscesses on final outcome and duration of percutaneous drainage. PATIENTS AND METHODS: Results were retrospectively reviewed for 11 patients with varying degrees of peritoneal contamination secondary to subacute bowel perforation who were primarily treated with percutaneous drainage. Stepwise linear regression analysis of duration of drainage was performed with use of patient age and immune status, the site of bowel perforation, and the number of peritoneal compartments involved in the resultant contamination as independent variables. RESULTS: In 10 of 11 patients (91%) treatment of the resultant intraperitoneal collections with percutaneous drainage was successful irrespective of the extent of peritoneal contamination. There was no correlation between duration of drainage and extent of peritoneal contamination but good correlation with patient age and site of bowel perforation (r = 0.82, P = .02). CONCLUSION: In patients with enteric abscesses due to subacute bowel perforation, the duration of drainage and final outcome after percutaneous drainage are independent of the extent of peritoneal contamination.

Imaging and intervention in abdominal emergencies.

While plain abdominal radiographs retain an essential place in acute abdominal emergencies, the dramatic advances in ultrasound, computed tomography and magnetic resonance imaging witnessed over the past two decades have revolutionized the practice of emergency medicine. Cross-sectional imaging techniques now play a key role in evaluating patients with abdominal emergencies, and allow confident diagnoses to be made in an ever increasing proportion of these patients. Unnecessary laparotomies are now uncommon, and a wide array of interventional radiological techniques can be used to treat abdominal emergencies without surgery.