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.

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.

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.

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.

Tumors of the adrenal gland: findings on CT and MR imaging

Adrenal gland imaging has improved drastically since the advent of CT and MR imaging. The purpose of this essay is to illustrate findings on cross-sectional imaging of adrenal gland tumors. Emphasis is given to imaging features that help to characterize specific lesions.

Radiologically guided percutaneous cholecystostomy for acute cholecystitis: long-term outcome in 50 patients

To assess the long-term outcome in patients with acute cholecystitis treated initially by percutaneous cholecystostomy, the authors reviewed the medical and radiology records of all such patients treated at their hospital from January 1990 to September 1993. Of the 50 patients, 29 had calculous and 21 had acalculous cholecystitis. In the group with calculous cholecystitis, 1 of the patients required no further treatment, 3 subsequently underwent percutaneous stone removal, 14 underwent elective cholecystectomy, 6 underwent emergency cholecystectomy and 5 died of the underlying condition shortly after cholecystostomy. In the group with acalculous cholecystitis, 12 of the patients needed no further treatment after a mean follow-up period of 12 months; 8 of these underwent follow-up ultrasound examination, which revealed gallbladder calculi in only 1 patient. Four patients underwent elective cholecystectomy, 1 underwent emergency cholecystectomy, and 4 died of the underlying condition shortly after cholecystostomy. Over the long term, 23 (79%) of the 29 patients with calculous cholecystitis underwent surgery or removal of calculi. In the other group surgery was required in only 5 (24%) of the 21 patients. The authors conclude that percutaneous cholecystostomy is a useful temporizing measure, which allows patients with calculous cholecystitis to undergo elective cholecystectomy. In most cases of acalculous cholecystitis the procedure is curative, obviating the need for cholecystectomy.

Effect of hyoscine butylbromide on gastroesophageal reflux in barium studies of the upper gastrointestinal tract

Hyoscine butylbromide (Buscopan) is an intravenously administered hypotonic agent that significantly reduces pressure in the lower esophageal sphincter and may therefore artificially induce gastroesophageal reflux during barium examination of the upper gastrointestinal tract. This study was performed to test this hypothesis. The presence or absence and severity of gastroesophageal reflux before and after intravenous injection of 20 mg Buscopan were evaluated in 112 consecutive patients undergoing biphasic upper gastrointestinal examination. Gastroesophageal reflux was seen in 49 (44%) of the patients. Reflux was evident both before and after the injection of Buscopan in 35 (31%) of the patients, before injection only in 10 (9%) and after injection only in 4 (4%). The magnitude of reflux after injection of Buscopan was reduced or the same in 108 of the patients (96%) and increased in 4 (4%). There was no significant difference in the overall occurrence (p = 0.41) or degree (p = 0.81) of gastroesophageal reflux before and after injection of Buscopan (chi 2 test). The authors conclude that the routine use of Buscopan is unlikely to spuriously increase the frequency or degree of gastroesophageal reflux observed on upper gastrointestinal barium studies.

Malignant obstruction of the common bile duct: long-term results of Gianturco-Rosch metal stents used as initial treatment

PURPOSE

To determine how long Gianturco-Rosch metal stents remain patent when used as the initial treatment for malignant obstruction of the common bile duct.

MATERIALS AND METHODS

The patency of Gianturco-Rosch metal stents was prospectively studied in 26 patients with malignant obstructive jaundice. Biliary obstruction was caused by pancreatic carcinoma (n = 15), cholangiocarcinoma (n = 10), or metastatic lymphadenopathy (n = 1). Follow-up information was obtained every 3-4 months until death.

RESULTS

Stent insertion was successful in all patients. Stent occlusion occurred in nine patients (35%). The overall mean patency period was 39.9 weeks. Adequate biliary drainage for a minimum of 80 weeks or until death was achieved in 19 patients (73%). Life-table analysis predicted stent patency rates of 86%, 75%, and 69% at 12, 24, and 48 weeks, respectively.

CONCLUSION

These results are better than those previously reported in patients with plastic endoprostheses. The authors believe that insertion of the metal stent is the procedure of choice in patients with inoperable malignant biliary obstruction.

Fluoroscopically guided percutaneous gastrostomy: tube function and malfunction

We describe our experience with fluoroscopically guided percutaneous gastrostomy, assessing in particular the functional performance of inserted tubes. We also examine the ability of radiological investigations to detect intraperitoneal gastrostomy leakage after the procedure. A functioning gastrostomy tube was established and maintained for as long as was required in 34 (89.5%) of 38 patients referred during a 21-month period. This necessitated further gastrostomy tube placements in 13 patients. On average, inserted gastrostomy tubes functioned for 10.75 weeks and during the review period a total of 34 malfunctioning tubes required replacement or removal. This was most commonly due to tube dislodgement, blockage, or intraperitoneal leakage. We found increasing pneumoperitoneum on sequential postprocedure erect chest films a reliable sign in the diagnosis of the latter complication. In conclusion, while we have been disappointed with aspects of individual tube function, our satisfactory overall functional success rate indicates that percutaneous gastrostomy is an effective method for establishing and maintaining enteral feeding. We also propose a protocol for the management of suspected intraperitoneal leakage based on the findings on postprocedure erect chest films.

Fluoroscopically guided percutaneous gastrostomy in patients with cystic fibrosis

The feasibility of fluoroscopically guided percutaneous gastrostomy in patients with cystic fibrosis is presented, highlighting differences between these and other patients undergoing the procedure.

The significance of fat and muscle areas in the lumbar paraspinal space: a CT study

OBJECTIVE

The object of this study was to determine the significance of fat deposition and muscle dimensions on CT in the unoperated lumbar paraspinal space.

MATERIALS AND METHODS

Fifty patients were prospectively studied. Paraspinal fat (PSF) and muscle (PSM) areas were correlated with various demographic and anatomical variables in patients with and without low back pain. The fat and muscle areas were derived from a standard CT image using a thresholding technique.

RESULTS

Regression equations indicated that the total amount of PSF increases with age and subcutaneous fat area. The PSM area decreases with age. There was no correlation with the other variables examined.

CONCLUSION

We conclude that PSF deposition and PSM dimensions on CT are related to patient age and the amount of subcutaneous fat. Paraspinal fat deposition is not a sign of muscle atrophy, and neither parameter is related to low back pain symptoms. Therefore, in patients who have not undergone spinal surgery, PSF and PSM areas are not of clinical or functional significance.

Accuracy of computed tomography during arterial portography in the segmental localization of liver tumours

The ability of computed tomography during arterial portography (CTAP) to identify and segmentally locate 20 hepatic tumours was prospectively assessed in 7 patients undergoing hepatic resection. All eight lesions greater than 2.5 cm in diameter were detected, but only two out of four and two out of eight of those measuring 1-2.4 cm and < 1 cm respectively. The overall segmental localization accuracy for detected lesions was 91%. Our results highlight the insensitivity of CTAP to hepatic lesions smaller than 1 cm in size, but have shown the accuracy of segmental localization for detected lesions.

Quantitative analysis of CT brain images: a statistical model incorporating partial volume and beam hardening effects

The purpose of this study was to construct and evaluate a statistical model for the quantitative analysis of computed tomographic brain images. Data were derived from standard sections in 34 normal studies. A model representing the intracranial pure tissue and partial volume areas, with allowance for beam hardening, was developed. The average percentage error in estimation of areas, derived from phantom tests using the model, was 28.47%. We conclude that our model is not sufficiently accurate to be of clinical use, even though allowance was made for partial volume and beam hardening effects.

Radiological investigation in laparoscopic compared with conventional cholecystectomy--an early assessment

The implications of laparoscopic cholecystectomy (LC) for radiology were assessed by comparing imaging investigations in 48 LC and 48 conventional cholecystectomy (CC) patients. In addition, we attempted to identify findings on pre-operative ultrasound (US) which predicted operative difficulties at LC. There were no per-operative or T-tube cholangiograms in the LC patients, but otherwise the pattern of investigation was similar in both groups. Forty of the 48 CC patients underwent cholangiography (per-operative cholangiography in 36, endoscopic retrograde cholangiopancreatography (ERCP) in two, and both in two) demonstrating calculi in eight (16.7%) cases. Only four LC patients had cholangiography (ERCP in all cases) demonstrating common bile duct (CBD) calculi in one (2.1%) case. Ultrasound failed to identify the gall-bladder with certainty in three of the five failed LC cases. Neither gall-bladder wall thickness, contraction nor calculus size on pre-operative US served as predictors of other per-operative difficulties. Our results indicate that there may be some patients with retained CBD calculi in the LC group. The role of pre-operative US in predicting operative difficulties needs further assessment in a prospective study.

Limb salvage in the elderly

Sixty-eight lower extremity bypass procedures for severe lower limb ischemia were undertaken on 53 patients of 75 years of age and over. The operative mortality was 4.4%. At two years cumulative limb salvage, patient survival, graft patency and survival with an intact limb were 77%, 72%, 44%, and 56%, respectively. Of all patients who died, 66% had an intact limb at the time of death. Based on these results we continue to offer reconstructive surgery to elderly patients.