Relationship of fat distribution to glucose tolerance. Results of computed tomography in male participants of the Normative Aging Study.

Computed tomography (CT) scanning was used to assess the relationship of glucose tolerance to fat distribution in men. Three cross sections [chest (including upper arms), abdomen, and thigh] were scanned in 41 men randomly selected from the Normative Aging Study, a longitudinal study of aging. Greater amounts of fat in the upper body and greater ratios of upper-body fat to lower-body fat were significantly correlated with higher 2-h serum glucose levels after adjustment for age and body mass index. In particular, intra-abdominal fat, a feature uniquely measured by CT, was a significant correlate of 2-h glucose. Largely parallel results were obtained when we compared a sample of male diabetic subjects (N = 8) with the male normal subjects from our random sample. This investigation demonstrates that body fat distribution, adjusted for overall degree of obesity, is a significant correlate of glucose tolerance even in a sample unselected for extremes of physique.

Assessment of abdominal fat content by computed tomography.

Computed tomography (CT) produces thin cross-sectional radiographs that may prove very useful in body composition research. CT images of the abdomen allow computerized measurement of total fat area, and also enable the differentiation of subcutaneous fat from intraabdominal fat. The preset investigation examines whether a single CT scan of the abdomen provides an accurate indication of overall abdominal adiposity. Graphs of measurements from seven sequential scans of the abdomen in eight patients showed that rankings of total abdominal area, total fat area, subcutaneous and intraabdominal fat area are relatively consistent no matter which abdominal level is chosen. Correlations of 0.89 to 0.99 between single scans and the average values for all scans show that a single CT image contains the same information on adiposity as a series of scans. These results suggest that future CT studies of body composition can limit radiation exposure by using single scans at different anatomical sites. If only a single scan at one site can be obtained, the level of the umbilicus may be the most useful, because it contains the largest percentage of fat in the body, and best allows differentiation of intraabdominal from subcutaneous fat.

Treatment of chronic pancreatitic pleural effusion by percutaneous catheter drainage of abdominal pseudocyst.

A 53-year-old man entered the hospital with a large, right chronic pancreatitic pleural effusion. Computed tomographic examination of the abdomen and chest demonstrated a pancreatic pseudocyst that had extended into the mediastinum. After conventional closed-chest tube thoracotomy drainage failed to empty the pleural space, percutaneous abdominal pseudocyst drainage was instituted using computed tomographic guidance. The pleural effusion cleared promptly, and the pancreatic pseudocyst resolved gradually over seven weeks. Following termination of pseudocyst drainage, the patient has remained well for over two years with no recurrence of pancreatitis, pseudocyst, or pleural effusion. In contrast, three earlier patients with a chronic pancreatitic effusion managed conventionally had a complicated hospital course and required surgical intervention; two had recurrent pancreatitis following hospital discharge. Percutaneous catheter placement was unsuccessful in one of these three and, in retrospect, was infeasible in the other two. It is recommended that thoracoabdominal computed tomography be performed in all patients with a chronic pancreatitic pleural effusion, and that percutaneous abdominal catheter drainage be attempted in all patients with an accessible pancreatic or mediastinal pseudocyst. Such treatment may relieve respiratory insufficiency, minimize the risk of empyema or fibrothorax, and may promote pseudocyst closure without the need for surgery.

Percutaneous drainage of infected pancreatic pseudocysts.

After diagnostic needle aspiration guided by computed tomography and/or ultrasound, 11 infected pseudocysts in ten patients were treated nonoperatively by percutaneous catheter drainage and intravenously administered antibiotics. Nine infected pseudocysts resolved after 11 to 37 days (mean, 21 days) with no recurrences at follow-up 16 to 42 months (mean, 24.4 months) later. All were confirmed by Gram's stain, culture, and elevated amylase levels. Ten of the pseudocysts were acute; one was chronic; five were polymicrobial; six had a single organism. There were no major complications. There was one failure when a pancreatic abscess developed in a patient who died following operative drainage. There was one successful palliation of a postoperative-infected pseudocyst in a patient with an obstructing nonresectable carcinoma of the head of the pancreas. A trial of percutaneous catheter drainage is indicated in patients with infected pancreatic pseudocysts.

Expanded criteria for percutaneous abscess drainage.

The original criteria for percutaneous abscess drainage were limited to simple abscesses (well-defined, unilocular) with safe drainage routes. We expanded these entry criteria to include complex abscesses (loculated, ill-defined, or extensively dissecting abscesses), multiple abscesses, abscesses with enteric fistulas or whose drainage routes traversed normal organs, as well as complicated abscesses (appendiceal, splenic, interloop, and pelvic). Using these expanded criteria, cure was achieved nonoperatively in 92 (73.6%) of 125 abscesses with ten deaths (9%), and 11 complications (9%). Cure was achieved in 82% of simple abscesses, but only 45% of complex abscesses. There was no correlation between size, depth, drainage route, or etiology of the abscess (spontaneous v postoperative) with either cure or complications. We recommend a trial of percutaneous drainage in all simple abscesses and most complex abscesses with clinical response as the key determinant of the need for operative intervention.

Central cavitary necrosis: differentiation from pancreatic pseudocyst on CT scan.

Central cavitary necrosis of the pancreas has a computed tomography CT appearance of a well-defined sausage-shaped mass with a low-density center and convex margins, usually conforming to the pancreatic contour. Several other entities, including pancreatic pseudocyst, may have a similar appearance. Since the treatment of central cavitary necrosis differs considerably from that of these other entities, it is important to differentiate them. We present CT criteria that help distinguish central cavitary necrosis from pancreatic pseudocyst and from a variety of other intrapancreatic and peripancreatic masses.

Bacteriologic status of necrotic tissue in necrotizing pancreatitis.

To confirm the accuracy of guided percutaneous aspiration (GPA) in distinguishing sterile from infected pancreatic necrosis, we have performed Brown-Brenn tissue Gram stains on pancreatic and peripancreatic necrotic tissue removed operatively in 15 patients. In eight patients judged to have sterile necrosis on the basis of negative cultures of pancreatic exudate obtained first preoperatively (by GPA) and then intraoperatively, necrotic tissue debrided at surgery was also free of bacteria. In seven patients judged to have infected necrosis on the basis of positive cultures of pancreatic exudate obtained first preoperatively (by GPA) and then intraoperatively, necrotic tissue debrided at surgery harbored a considerable number of bacteria. We conclude that GPA targeted to areas of necrosis accurately distinguishes infected necrosis from sterile necrosis, and in infected necrosis, the solid necrotic tissue as well as the fluid component contains bacteria. We therefore believe that infected necrosis is not likely to be eradicated by catheter drainage and should be treated by surgical debridement.

CT of appendicitis. Diagnosis and treatment.

CT may provide valuable information in patients with appendicitis whose clinical presentations are atypical. The abnormal appendix and inflammatory changes in the pericecal fat are shown directly rather than inferentially. CT can reliably distinguish phlegmonous inflammation from a liquified abscess and can accurately delineate the full extent of such inflammatory masses. Percutaneous catheter drainage of well-localized appendiceal abscesses under CT guidance is safe and effective and has a lower morbidity than surgical drainage.

Intrahepatic pyogenic abscesses: treatment by percutaneous drainage.

During a 6 year period, 18 liver abscesses in 12 patients were identified by computerized tomography. Five patients had presumed hematogenous seeding. Five patients previously had bilioenteric anastomoses, stents, or both to relieve obstructive jaundice. Four patients with abscesses had recent abdominal operations. Diagnosis was established by guided needle aspiration and treatment was provided by percutaneous catheter drainage. Organism-specific antibiotics were administered to all patients. Patients were evaluated for recurrence by serial computerized tomographic studies and were clinically followed up for a minimum of 15 months. Ten of 12 patients (83 percent) and 16 of 18 abscesses (89 percent) were successfully treated by percutaneous catheter drainage. Two failures required operative intervention. In summary, the low morbidity and high success rate in treating hepatic abscesses by percutaneous drainage suggests that this therapy be tried before operative intervention is considered.

Computed tomographic angiography.

Computed tomographic angiography performed by the intravenous administration of contrast medium was evaluated in 86 vascular patients. This experience demonstrates a new approach to the evaluation of patients with symptomatic aortic aneurysms, in whom computed tomographic angiography will aid in evaluating the need for emergency surgery. Nonoperative patients are serially evaluated by computed tomographic angiography to detect significant changes in the geometric configuration of their aneurysms. Computed tomographic angiography was beneficial in the evaluation of the patency of vascular reconstructive procedures such as femoropopliteal bypass, aortoiliac bypass and application of a vena caval device. More clinical experience and possibly a rapid sequence technique are needed to evaluate patients with portasystemic shunts.

Imaging techniques for infections in the surgical patient.

Gallium-67 citrate is easy to use and readily available, but the need to delay imaging for 2 to 4 days after injection hinders rapid diagnosis. Moreover, normal gastrointestinal activity limits its usefulness in evaluating the abdomen. Labeling leukocytes with Indium-111 oxine is a time-consuming, technically involved process, yet the images obtained at 24 hours will usually reveal sites of inflammation or infection. Although the techniques have similar sensitivities, the higher specificity of In-111 makes it the superior agent for many clinical situations. When there are localizing signs or symptoms or a reason to suspect a specific body region, CT or ultrasonography is the imaging modality of choice. Guided needle aspiration can then be performed and is usually diagnostic. Radionuclide imaging with either Ga-67 or In-111 is available as an adjunct if needle aspiration cannot be performed or is inconclusive. Since it provides total-body surveillance, radionuclide imaging is particularly useful for screening when there are no localizing signs and in cases of occult sepsis or fever of unknown origin. If positive, it can direct further imaging with CT or ultrasound.

Radiologic aspects of diagnosis and treatment of abdominal abscesses.

The precise anatomic display by computed tomography and ultrasonography provides the guidance to make diagnostic needle aspiration a safe routine procedure. Percutaneous catheter drainage of abdominal abscesses now offers an alternative to surgery and has already become a well-established radiologic procedure in many centers.

Percutaneous drainage of renal and perinephric abscess.

Computed tomography and ultrasonography are effective methods for diagnosis and localization of renal and perinephric abscesses. In patients with clinical suspicion of sepsis, diagnostic needle aspiration of these lesions can be safely performed extraperitoneally by using sectional imaging for guidance. When an abscess is confirmed, small catheters can be introduced percutaneously via the diagnostic aspiration route to provide immediate decompression as well as continuous and definitive drainage without need for surgery. In 8 cases so treated, there were no major complications, deaths, or recurrences. These results, obtainable without the risks of surgery, indicate that patients with renal or perinephric abscesses should be offered a trial of percutaneous drainage as a definitive method of therapy. Those cases not amenable to percutaneous drainage, or those in which the procedure has failed, can then be drained surgically. Percutaneous abscess drainage is widely applicable because it can be performed in any uroradiologic facility with access to sectional imaging.