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Purpose: The purpose of this study was to evaluate the role of endovascular aneurysm repair in high-risk patients., Methods: The elective endovascular repair of infrarenal aortic aneurysm was performed in 116 high-risk patients with either custom-made or commercial stent grafts. The routine follow-up examination included contrast-enhanced computed tomography (CT) before discharge, at 3, 6, and 12 months, and annually thereafter. Patients with endoleak on the initial CT underwent re-evaluation at 2 weeks. Those patients with positive CT results at 2 weeks underwent endovascular treatment., Results: Endovascular repair was considered feasible in 67% of the patients. The mean age was 75 years, and the mean aneurysm diameter was 6.3 cm. The American Society of Anesthesiologists grade was II in 3.4%, III in 65.5%, IV in 30.1%, and V in 0.9%. There were no conversions to open repair. Custom-made aortomonoiliac stent grafts were implanted in 77.6% of the cases, custom-made aortoaotic stent grafts in 11.2%, and commercial bifurcated stent grafts in 11.2%. The 30-day rates of mortality, major morbidity, and minor morbidity were 3.4%, 20.7%, and 12%, respectively, in the first 58 patients and 0%, 3.4%, and 3.4%, respectively, in the last 58. The late complications included five cases of stent graft kinking, two cases of femorofemoral graft occlusion, and three cases of proximal stent migration, one of which led to aneurysm rupture. At 2 weeks after repair, endoleak was present in 10.3% of the cases. All the type I (direct perigraft) endoleaks underwent successful endovascular treatment, whereas only one type II (collateral) endoleak responded to treatment. The technical success rate at 2 weeks was 86.2%, and the clinical success rate was 96.6%. The continuing success rate was 87.9%. Seventeen patients died late, unrelated deaths., Conclusion: Endovascular aneurysm repair is safe and effective in patients at high risk, for whom it may be the preferred method of treatment.

The relative merits of aortomonoiliac and bifurcated stent-graft configurations depend on the patient's arterial anatomy and clinical status. Aortomonoiliac stent-grafts are simple to make, simple to insert, and versatile. They are most useful when the iliac artery anatomy is severely distorted and the patient is old, sick, and inactive. The main problems with this approach are all consequences of femorofemoral bypass. The bifurcated stent-graft is the preferred alternative in healthy patients, because it ensures flow to both common iliac arteries, thereby eliminating the need for femorofemoral bypass. However, bifurcated stent-grafts and their delivery systems are difficult to make and difficult to deploy, especially when the iliac anatomy is distorted or emergency circumstances preclude preoperative sizing. This article addresses the advantages and disadvantages of the aortomonoiliac graft.

Objective: The purpose of this study was to compare colonic distention with and without glucagon hydrochloride during CT colonography., Subjects and Methods: CT colonography using single breath-hold, thin-section helical technique was performed on 60 patients who were in the supine and prone positions. Magnesium citrate and polyethylene glycol were used for bowel preparation. Colonic air insufflation averaged 30 bulb compressions. Thirty-three patients received IV glucagon (1 mg), and 27 patients did not. The colon was divided into eight segments, and the adequacy of the distention of each segment was evaluated. Overall colonic distention scores, defined as the number of inadequately distended segments (0-8), were recorded for the supine, prone, and combined positions. In the combined position, inadequate distention was defined as identical segments that were inadequately distended in both positions., Results: A total of 960 segments were evaluated: 528 segments in the glucagon group and 432 segments in the nonglucagon group. In the glucagon group, 444 segments (84.1%) were adequately distended. In the nonglucagon group, 365 segments (84.5%) were adequately distended. The median and range for overall colonic distention scores in the supine, prone, and combined positions were 1 (0-3), 1 (0-3), and 0 (0), respectively, for the glucagon group and 1 (0-6), 1 (0-6), and 0 (0-1), respectively, for the nonglucagon group. We found no statistically significant difference in overall colonic distention between the glucagon group and the nonglucagon group for the supine (p = .84), prone (p = .15), or combined (p = .28) positions., Conclusion: Glucagon administration before CT colonography does not improve colonic distention.

Purpose: To assess the safety and efficacy of endovascular repair of abdominal aortic aneurysm in high-risk patients during the short to intermediate term., Materials and Methods: Endovascular aneurysm repair was performed in 50 patients considered too high risk for conventional repair. Stent-grafts were inserted through surgically exposed femoral arteries with fluoroscopic guidance. The anesthetic technique was epidural in 36 patients, general in 12, and local in two. Aortouniiliac stent-grafts were inserted in 42 patients and aortoaortic in eight., Results: There were no deaths and no conversions to open surgical repair. The primary success rate (complete aneurysm exclusion according to CT criteria) was 88% (44 of 50). The secondary, clinical, and continuing success rates were all 98% (49 of 50). Surgical time was 196 minutes +/- 67 (mean +/- SD), blood loss was 284 mL +/- 386, and volume of contrast material administered was 153 mL +/- 64. The time from the end of the surgery to resumption of a normal diet was 0.58 days +/- 0.56, to ambulation was 1.22 days +/- 0.77, and to discharge from the hospital was 3.63 days +/- 1.60. Wound problems accounted for the majority of complications. There were no instances of pulmonary failure, renal failure, stent-graft migration, or late leakage., Conclusion: Endovascular repair of abdominal aortic aneurysm is feasible in two-thirds of high-risk patients, with a low mortality and high success rate during the short to intermediate term.

Background: Hemorrhage from esophageal varices remains a substantial management problem. Endoscopic sclerotherapy was preferred for more than a decade, but fluoroscopically placed intrahepatic portosystemic stents have recently been used with increasing frequency., Objective: To compare sclerotherapy with transjugular intrahepatic portosystemic shunt (TIPS) in patients with bleeding from esophageal varices., Design: Randomized, controlled clinical trial., Setting: Three teaching hospitals., Patients: 49 adults hospitalized with acute variceal hemorrhage from November 1991 to December 1995: 25 assigned to sclerotherapy and 24 assigned to TIPS., Intervention: Patients assigned to repeated sclerotherapy had the procedure weekly. In those assigned to TIPS, an expandable mesh stent was fluoroscopically placed between an intrahepatic portal vein and an adjacent hepatic vein., Measurements: Pretreatment measures included demographic and laboratory data. Postrandomization data included index hospitalization survival, duration of follow-up, successful obliteration of varices, rebleeding from varices, number of variceal rebleeding events, total days of hospitalization for variceal bleeding, blood transfusion requirements after randomization, prevalence of encephalopathy, and total health care costs., Results: Mean follow-up (+/-SE) was 567 +/- 104 days in the sclerotherapy group and 575 +/- 109 days in the TIPS group. Varices were obliterated more reliably by TIPS than by sclerotherapy (P < 0.001). Patients having TIPS were significantly less likely to rebleed from esophageal varices than patients receiving sclerotherapy (3 of 24 compared with 12 of 25; P = 0.012). No other follow-up measures differed significantly between groups. A trend toward improved survival, which was not statistically significant, was noted in the TIPS group (hazard ratio, 0.53 [95% CI, 0.18 to 1.5])., Conclusions: In obliterating varices and reducing rebleeding events from esophageal varies, TIPS was more effective than sclerotherapy. However, TIPS did not decrease morbidity after randomization or improve health care costs. It seemed to produce better survival, but the increase in survival was not statistically significant.

As the AIDS epidemic continues to grow, it becomes increasingly important that physicians are aware of the gastrointestinal and abdominal diseases specific to this group of patients. Most AIDS patients exhibit gastrointestinal symptoms at some time during the course of their disease. Clinical AIDS is often determined by identifying an opportunistic infection or neoplasm of the gastrointestinal tract. Radiology often plays a key role in helping to determine the diagnosis as well as in directing the management.

Infectious esophagitis is most often seen in patients with impaired host resistance. It has become a particular problem in the growing AIDS population. The three most commonly encountered opportunistic infections of the esophagus are Candida albicans, herpes simplex virus, and cytomegalovirus. Candida is the single leading cause of infectious esophagitis. Tuberculous and bacterial esophagitis and other unusual fungal infections of the esophagus are uncommon.

Magellan images reveal surface features on Venus attributed to wind processes. Sand dunes, wind-sculpted hills, and more than 5830 wind streaks have been identified. The streaks serve as local "wind vanes," representing wind direction at the time of streak formation and allowing the first global mapping of near-surface wind patterns on Venus. Wind streaks are oriented both toward the equator and toward the west. When streaks associated with local transient events, such as impact cratering, are deleted, the westward component is mostly lost but the equatorward component remains. This pattern is consistent with a Hadley circulation of the lower atmosphere.

Gastrointestinal disease in two groups of immunocompromised patients, namely the AIDS patient and the post-bone marrow transplant patient, are discussed. Disease entities include opportunistic infections, Kaposi's sarcoma, lymphoma and other B cell proliferative disorders, cancer following transplantation, typhlitis, and pseudomembranous colitis.

As the AIDS epidemic progresses, concern about the risk of occupational transmission of the causative organism, human immunodeficiency virus (HIV), is increasing. In this article, we summarize the risk of occupational acquisition of HIV in the health care setting and specify protocol and equipment that can reduce this risk in the radiology department. Accidental needle-stick injury is the most common form of exposure to infected blood, which is the only body fluid implicated to date in the occupational transmission of HIV. Prospective cohort studies demonstrate a 0.3-0.4% risk of infection for each needle-stick event. The most important instruction to health care workers that can reduce this risk is the following: Do not recap needles. Other risk-reduction measures include the adoption of universal precautions against transmission of infectious disease; sharp-instrument precautions; the use of protective garb to prevent skin and mucous membrane contamination when blood or bloody body fluid may splash; the availability of stable, puncture-resistant disposal containers for sharp instruments; the exclusion of breakable glass syringes; and the accessibility of resuscitation equipment in all rooms in order to avoid direct mouth-to-mouth contact. These and other measures discussed here are designed to prevent exposure of skin or mucous membrane to blood. If exposure does occur, the contaminated area should be washed immediately. A multicenter research protocol to evaluate the effectiveness of zidovudine (AZT) therapy in preventing seroconversion after exposure to HIV-contaminated blood recommends AZT therapy after massive exposure (e.g., injection of measurable quantities of blood) and endorses it for serious parenteral exposure (e.g., deep needle sticks).

An analysis of the utility of parenteral ceruletide, a cholecystokinin-like synthetic decapeptide, in promoting bowel opacification for computed tomography (CT) scanning was performed. Abdominal and pelvic CT scans of 85 patients who had received intramuscular ceruletide following oral contrast administration and of 85 control patients were reviewed and the degree of bowel opacification evaluated. No significant advantage was conferred by ceruletide in opacifying the stomach or major part of the small intestine. However, a statistically significant difference was found between the 2 groups in the presence or absence of contrast in the terminal ileum and right colon. Contrast was detected in the terminal ileum in 52 experimental compared with 35 control patients (p less than 0.009) and in the right colon in 56 experimental and 39 control subjects (p less than 0.01). Intramuscular administration of ceruletide will be helpful when terminal ileal opacification is essential or in patients in whom colonic opacification is desired but rectal contrast contraindicated.

On review of 63 barium sulfate examinations in 44 patients with acquired immunodeficiency syndrome (AIDS), 61% of the 23 single-contrast examinations and 98% of the 40 double-contrast examinations were abnormal. Abnormalities involved all areas of the gastrointestinal (GI) tract and covered a wide spectrum of findings including thickened folds, nodularity, increased secretions, superficial erosions, ulcerations, plaque formation, and tumor mass. Abnormalities, when present, were most commonly multifocal (three or more sites) on upper GI study (64%) and barium enema (69%). Thirty-eight patients (86%) had at least one abnormal study; 27 of these patients had multifocal disease in either the upper or lower tract separately or combined. The most common site of abnormality was the duodenum on upper GI study and the sigmoid colon on barium enema. In 27 cases the radiographic abnormalities could be specifically correlated with a malignancy or an opportunistic infection by endoscopy, colonoscopy, culture, biopsy, or autopsy. Multifocal disease of the upper and/or lower GI tract, especially when the duodenum is involved, should suggest AIDS even in patients not thought to be at high risk for the disease.

The development of magnetic resonance imaging ( MRI ) is in an exponential phase and holds unbelievably exciting possibilities for the future of diagnostic medicine. It has many advantages and very few disadvantages compared to other imaging modalities. MRI is rapidly becoming the preferred method for the study of most organs. Spectroscopy will bei combined with imaging and will lead to the study of small volumes of normal and abnormal tissue selected from the MR proton density imager.

Twenty-six patients with clinically documented acute cerebral infarction were evaluated by computed tomography within the first 24 hr. In 21 patients, subtle mass effects and/or focal areas of decreased attenuation corresponding to areas of clinical deficit were demonstrated. Enhancement occurred in only five of 15 infarctions rescanned after contrast administration. In three of these, the region of infarction became isodense after contrast administration. In a patient with multifocal infarcts, enhancement was the only clue to infarction in one focus. The improved spatial and contrast resolution of current generation scanners appears to have significantly increased the sensitivity of computed tomography in demonstrating acute cerebral infarction and has important clinical application.

Until recently pancreatic abscess was often a lethal complication of acute pancreatitis. A major factor contributing to this high mortality has been delay in diagnosis. When combined with diagnostic needle aspiration, computed tomography (CT) has greatly enhanced the early detection of pancreatic abscesses. In the past 5 years at our institutions 23 patients with proven pancreatic abscesses were evaluated early in their clinical course by CT. In follow-up ranging from 4 months to 4 1/2 years there were only 4 deaths: a mortality rate of 17%. Many of the surviving patients had a long and protracted clinical course (mean length of hospitalization, 58 days) and reoperation for recurrent abscess or gastrointestinal complications was required in 9 patients (39%). Computed tomography proved helpful both in localizing the site of de novo or recurrent pancreatic abscess and in detecting postoperative complications. An aggressive approach to early CT scanning with diagnostic needle aspiration appears to be a factor in the improved survival of these patients.

The clinical and pathologic features were evaluated in 106 IgA nephropathy patients identified in 1,753 consecutive patients undergoing renal biopsy in the southeastern United States. Special attention was paid to the proportion of Blacks among the IgA nephropathy patients compared with non-IgA nephropathy patients, and any differences in clinical or pathologic findings between Whites and Blacks with IgA nephropathy. The incidence of IgA nephropathy was approximately six times lower in Blacks (6 out of 461) than in Whites (100 out of 1,292) undergoing renal biopsy (P less than 0.001). There were no morphologic or immunohistopathologic differences between Whites and Blacks with IgA nephropathy. The only clinical difference was a marked shift in the male to female sex ratio from 3.5:1 in Whites to 1:5 in Blacks (P less than 0.004). The low incidence and reversed sex ratio of IgA nephropathy in Blacks were also supported by a review of previously published data.

Computerized tomographic scanning is being used with increasing frequency for the detection of abdominal aortic prosthetic complications. Although computerized tomography remains a very precise method for direct imaging of the retroperitoneal space, the interpretation of a postoperative computerized tomographic scan is limited by the absence of any information on the normal appearance of the routine uncomplicated aortic graft. To study the normal tissue incorporation of aortic grafts, 29 patients were evaluated with periodic postoperative computerized tomographic scans. Seventeen patients had aortoiliac occlusive disease and 12 had aneurysmal disease. No patients who had reoperation were included and all patients had a normal postoperative course. Computerized tomographic scans were obtained in the early (mean 7 days), intermediate (mean 48 days), and late (mean 102 days) postoperative periods. A variable amount of perigraft hematoma was always present on the initial computerized tomographic scan. Perigraft air was seen in only four patients in the early study. Graft incorporation appeared complete in these patients by 48 days, although minimal hematoma persisted in one patient. This study provides baseline data on the appearance and timing of aortic graft incorporation which should facilitate subsequent computerized tomographic detection of aortic graft complications.

Barium radiography of the gastrointestinal tract in patients with AIDS can assist in the evaluation of numerous problems including dysphagia, odynophagia, diarrhea, abdominal pain, symptoms of intermittent obstruction, and/or gastrointestinal bleeding. It can localize disease, evaluate complications, guide endoscopic biopsy, and monitor the progress of therapy.

The radiographic appearance of gastrointestinal Kaposi's sarcoma in patients with AIDS has been described previously, but little attention has been paid to pharyngeal involvement. This study compared the radiographic findings of pharyngeal Kaposi's sarcoma in eight patients with AIDS and dysphagia to those of visual inspection by laryngoscopy or bronchoscopy. Barium pharyngography (six patients) demonstrated nodular lesions without ulceration, ranging in extent from a single nodule to extensive confluent disease. CT (two patients) showed nodular or polypoid intraluminal protrusions, distortion of valleculae and pyriform sinuses, infiltration of deep-tissue planes, and adenopathy. A 4-mm nodular lesion was not seen on pharyngography. Radiographic evaluation provided supplemental information in six patients, especially regarding inferior extent of disease in four whose bulky lesions precluded adequate visual assessment. CT aided in defining deep-tissue-plane involvement and extent of nodal disease. It is concluded that barium pharyngography and CT are useful in the diagnostic evaluation of possible Kaposi's sarcoma in patients with AIDS and dysphagia.

Normal CT attenuation values for various structures in the lumbar spine were obtained on several CT scanners. The wide range of normal makes using absolute CT numbers unreliable. The utility and pitfalls of using CT attenuation numbers in the lumbar spine are discussed and several examples are illustrated. CT numbers used as absolute values can be misleading, whereas, when used as relative values for comparison with other structures, they can be quite valuable.

Review of abdominal CT scans for evaluation of blunt abdominal trauma yielded 35 cases of pneumothorax, 10 of which had not been diagnosed before CT by clinical examination or plain radiographs. Of the 10 cases initially diagnosed on CT, seven required tube thoracostomy for treatment of the pneumothorax. CT detection of pneumothorax is especially important if mechanical assisted ventilation or general anesthesia is used. Demonstration of pneumothorax requires viewing CT scans of the upper abdomen (lower thorax) at lung windows in addition to the usual soft-tissue windows.

The effect of glucagon-induced hypotonicity on the diagnostic accuracy of double-contrast barium enema examinations was determined in 133 consecutive patients in a double-blind crossover study. All patients underwent colonoscopy and served as their own controls by undergoing a double-contrast study after intravenous injection of 1 mg of glucagon and another after intravenous injection of 1 ml of saline placebo, in randomized order. The frequencies of good/excellent hypotonicity and quality of examinations after first doses of glucagon (55.3% and 80.8%) were not significantly different from the frequencies of good/excellent results after first doses of saline (51.3% and 86.5%). The sensitivity was 72.6% after glucagon and 64.5% after placebo; the specificity was 88.7% after glucagon and 77.9% after placebo; and the respective accuracies were 81.2% and 71.9%. These percentages should be used only to compare results with and without glucagon and, by study design, do not represent results of a complete double-contrast study. The variation among these percentages was not statistically significant, but diverticulitis was more accurately diagnosed after glucagon. It was concluded that glucagon does not significantly improve the sensitivity and specificity of the double-contrast barium enema examination and should be used only in selected instances.

In order to determine the most appropriate window settings for viewing CT of the bronchial tree, we performed CT of a bronchial phantom consisting of air-filled tubes measuring from 3.1 to 12.7 mm, oriented at varying angles relative to the scan plane, surrounded by water or air, and with scan collimation of 10 mm, 5 mm, and 1.5 mm. Using a computer program to graphically display CT number relative to the distance across the tube's lumen, it was found that a window mean of -150 H accurately estimated the internal diameter of tubes surrounded by water, at all angles, when collimation was 5 mm or 1.5 mm. With 10-mm collimation, tube diameter was slightly underestimated for tubes 9.5 mm or less when oriented 30 degrees or more from perpendicular to the plane of scan. At lower window settings and window widths of 500 H or less, all tube's diameters were significantly underestimated. At -150 H, with tubes parallel to and centered in the scan plane, 5-mm and 1.5-mm collimation were most accurate; with decentering of 4 mm, 10-mm collimation better showed the tube's lumen. When surrounded by air, tube wall thickness was best estimated using a window mean of -450 H.

Acquired immunodeficiency syndrome (AIDS) is a lethal infectious disease that has reached epidemic proportions in urban centers of the United States. Intraabdominal opportunistic infections and malignancies are common features of this syndrome. A prodromal phase or possibly milder form of infection is known as the AIDS-related complex. Abdominal computed tomography (CT) in patients with AIDS-related complex often demonstrates a triad of mild retroperitoneal and mesenteric adenopathy, splenomegaly, and perirectal inflammation. Lymph node enlargement greater than 1.5 cm is unusual in the AIDS-related complex and should prompt CT-guided biopsy. Abdominal adenopathy (greater than 1.5 cm) in AIDS, in our experience, is most commonly related to non-Hodgkin lymphoma, Kaposi sarcoma, or infection with Mycobacterium avium-intracellulare. In most instances, CT-guided biopsy with appropriate staining technique can readily distinguish these entities. However, the subtyping of non-Hodgkin lymphoma by fine-needle aspiration biopsy alone remains controversial. Unusual features of abdominal malignancies are common in AIDS. These include a purely lymphadenopathic form of AIDS-related Kaposi sarcoma and a predilection for extranodal sites of lymphoma in AIDS. In general, patients with AIDS-related lymphoma present with advanced stages of disease with highly malignant histologic subtypes. Abdominal CT may be useful clinically for diagnosing intraabdominal complications of AIDS.

Cryptosporidiosis is a parasitic disease of the gastrointestinal tract that causes a choleralike diarrhea in patients with the acquired immunodeficiency syndrome (AIDS). Review of barium studies of the stomach and small intestine in 16 AIDS patients with cryptosporidiosis showed that the studies were abnormal in 13. Of these, five had moderate or marked prominence of the mucosal folds, and eight had slight prominence. The jejunum was predominantly involved in nine; the entire small intestine was uniformly affected in the other four. Three of the 16 patients had moderate or marked dilatation of the small intestine. One had marked dilution of the barium, and one had marked fragmentation and flocculation of the barium. There was narrowing and rigidity of the gastric antrum in two patients. These radiographic findings are nonspecific, but are indicative of cryptosporidiosis in a patient with AIDS and protracted diarrhea.

Coma is a frightening state requiring immediate medical attention. Because the patient's history may be unavailable and the possible causes of coma are numerous, the physician must concurrently support and protect the patient and evaluate the cause of coma. A systematic, orderly approach to diagnosis, using modern diagnostic tools to complement thorough physical examination, can help illuminate and alleviate this often perplexing problem.

A retrospective comparison was made of the capability of magnetic resonance (MR) imaging and CT to display and characterize pathologic abdominal fluid collections. Fluid collections in 41 patients were analyzed: ascites (seven patients), hematoma (five), pancreatic pseudocyst (four), biloma (two), abscess (four), simple renal cyst (nine), hemorrhagic renal cyst (two), hydronephrosis (four), hemonephrosis (two), and cystic metastases (two). Most fluid collections were equally demonstrated by the two modalities. Walls around fluid collections were better demonstrated CT. Six fluid collections appeared heterogeneous on MR but were homogeneous or nearly so on CT.

Retrograde insufflation of air into the terminal ileum via a rectal tube (peroral pneumocolon) is a simple adjunct to the conventional gastrointestinal small-bowel follow-through examination. The purpose of this study was to determine the feasibility and diagnostic value of peroral pneumocolon in 170 patients who were being evaluated by upper gastrointestinal series with conventional small-bowel follow-through. Retrograde passage of air into the terminal ileum was successful in 87% of 140 patients with normal anatomic relations and in all 30 patients with small bowel-colonic anastomoses. In most cases, retrograde air insufflation yielded additional diagnostic information, particularly in detection of ulcerations, edematous mucosa, and cobblestone patterns. The length of the small bowel segment affected by pathologic changes could be determined more accurately in over 60% of the peroral pneumocolon examinations. No procedure-related complications were observed.

The effects of hypoxic hypoxia on high-energy phosphate metabolites and intracellular pH (pHi) in the brain of the anesthetized infant rabbit were studied in vivo using 31P nuclear magnetic resonance spectroscopy. Five 10- to 16-day-old rabbits were anesthetized with 1.5% halothane. Ventilation was controlled to maintain normocarbia. Inspired O2 fraction was adjusted to produce three states of arterial oxygenation: hyperoxia (PaO2 greater than 250 mm Hg), normoxia (PaO2 approximately 100 mm Hg), and hypoxia (PaO2 25-30 mm Hg). During hypoxia, blood pressure was kept within 20% of control values with a venous infusion of epinephrine. During hyperoxia, the phosphocreatine-to-ATP ratio was 0.86, a value that is 2-2.5 times less than that reported for adults. During normoxia, ATP decreased by 20% and Pi increased by 90% from hyperoxia values. During 60 min of hypoxia, the concentrations of high-energy phosphate metabolites did not change, but intracellular and arterial blood pH (pHa) decreased significantly. When hyperoxia was reestablished, pHi returned to normal and pHa remained low. These results suggest that during periods of hypoxemia, the normotensive infant rabbit maintains intracellular concentrations of cerebral high-energy phosphates better than has been reported for adult animals.

A 17-year-old Laotian refugee developed an ultimately fatal disease process characterized by formation of an abdominal eosinophilic mass, peripheral eosinophilia, and elevated serum IgE. No parasitic pathogens that could explain her disease were isolated during life or identified at autopsy. Furthermore, the disease was not consistent with previously described neoplastic, inflammatory, or idiopathic diseases. We believe this process represents a unique, aggressive variation of the hypereosinophilic syndrome, and that immunosuppressive therapy may be warranted.

Ten patients with percutaneous biopsy or surgically proven abscesses were evaluated with magnetic resonance imaging (MRI) to describe the appearance of abscesses, define the capability of MRI to localize abscesses, and compare the capabilities of MRI and CT for the diagnosis and determination of the extent of an abscess. Comparative CT scans were available in six cases. The most common MRI finding was an abnormal area of low signal intensity, either homogeneous or heterogeneous, on the short repetition rate (500 msec TR) images with a relative increase in signal intensity on the longer repetition rate (1500 or 2000 msec TR) images. MRI demonstrated a more clear delineation of the extent of inflammatory changes than did CT, and MRI demonstrated the abscess as a collection distinct from surrounding structures on at least one repetition rate. Intravenous contrast medium was unnecessary with MRI to evaluate vasculature or to define the capsule around an abscess. With CT, unless an abscess contained air or was of low attenuation, it often blended with the surrounding structures and was difficult to differentiate from them. Surgical clips in the postoperative patient with an abscess did not degrade the MR images as often occurred with CT. This study describes the MRI appearance of abscess and indicates a potential value of the use of MRI to evaluate abscess outside the central nervous system and spine.

The acquired immunodeficiency syndrome (AIDS) is an increasingly important disease that has become a social phenomenon. Although our therapeutic options for treating AIDS patients are limited at present, radiologic investigation is often of crucial importance in determining the extent and stage of opportunistic infections and neoplasms. This manuscript deals in depth with the manifestations of AIDS in the chest, abdomen, and central nervous system. It emphasizes the importance of cross-sectional imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound as well as guided fine needle aspiration biopsy. The first chapter is a brief overview of the general management of AIDS patients in the radiology department. It seeks to emphasize a careful caring approach to patients with this disease. It also emphasizes the importance of educating all radiology personnel to an awareness of how precautions can be taken to avoid the spread of AIDS while dealing with patients in a professional, courteous manner.

This study evaluated the ability of magnetic resonance imaging (MRI) to depict the hepatic vasculature and surgical anatomy of the liver using the transaxial, coronal, and sagittal planes. Retrospective analysis of the abdominal MRI examinations of 94 patients was performed. The spin-echo imaging technique was used to obtain transaxial images in all patients and coronal and sagittal sections in 35 of these patients. Overall, the hepatic vasculature was better delineated on the longer repetition rates (2000 msec TR) and the first echo images (28 msec TE). The inferior vena cava, right and middle hepatic veins, and main and right portal veins were seen in 100% of the cases in the transaxial plane. The left hepatic vein was seen in 98%, the left portal vein in 93%, and the hepatic artery in 44% in the transaxial plane. In the sagittal and coronal planes, the inferior vena cava and main and right portal veins were seen in 100% of cases. The other hepatic vasculature was less frequently demonstrated. In the sagittal plane, the right hepatic vein was seen in 85% of the cases, the left hepatic vein in 62%, the middle hepatic vein in 90%, the left portal vein in 90%, and the hepatic artery in 14%. In the coronal plane, the right hepatic vein was seen in 85% of cases, the left hepatic vein in 14%, the middle hepatic vein in 79%, the left portal vein in 71%, and the hepatic artery in 7%. These results are from preliminary work. Further developments with MRI technology may render better visualization of hepatic vasculature.