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The purpose of this study was to assess the efficacy of spiral computed tomography (CT) in determining the etiology of biliary tract obstruction. Spiral CT studies performed over a 9-month period in 42 consecutive patients with suspected biliary tract obstruction were reviewed. Analysis of scans included localizing the obstruction and then defining a specific etiology. Pertinent associated findings such as porta hepatis or peripancreatic adenopathy, hepatic or peritoneal metastases, and pancreatic pseudocyst or abscess formation were also assessed. Spiral CT demonstrated the level of obstruction in all 30 patients in whom there was biliary tract dilatation. Thirty-two diagnoses were rendered in 30 patients, with specific obstructing lesions identified in 28 instances (88%). Twenty-five (78%) of 32 specific pathological diagnoses were correct. The positive predictive value for neoplasms in the pancreatic head was 100% (n = 17). Two patients with characteristic CT changes of sclerosing cholangitis were diagnosed as having superimposed cholangiocarcinoma, although the results of biopsies for neoplasm were negative. The sensitivity of spiral CT for detection of common duct calculi was 67% (n = 3). Due to optimal contrast enhancement of both hepatic and pancreatic parenchyma, spiral CT enables excellent visualization of the biliary system and provides a specific explanation for biliary tract obstruction in nearly all cases. Spiral CT can usually distinguish neoplastic from nonneoplastic causes of jaundice. When distal common duct obstruction is detected in the absence of an identifiable mass or focal ductal wall thickening, neoplasia is unlikely. It is difficult to exclude sclerosing cholangitis from cholangiocarcinoma on the basis of spiral CT findings, and in these patients, biopsy or close follow-up is recommended to exclude the possibility of a biliary neoplasm.

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While uncommon, many musculoskeletal disorders may be seen in association with the acquired immune deficiency syndrome (AIDS). Infections such as osteomyelitis, bacterial myositis and septic arthritis, neoplasms such as non-Hodgkin lymphoma and Kaposi sarcoma, and myopathies and polymyositis have been reported in this patient population. Computed tomography and magnetic resonance imaging frequently detect unanticipated musculoskeletal disease in a patient with AIDS, and may further help to distinguish infections from neoplastic disorders.

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Spiral CT is ideally suited for evaluation of the kidneys. Continuous data acquisition and uniform contrast enhancement improve characterization of renal pathology. This article provides examples of the spiral CT appearance of various nonneoplastic conditions, with emphasis on renal cystic disease, inflammatory disease, and vascular disease.

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Spiral CT offers many advantages in the evaluation of renal masses. It is especially helpful in the detection and characterization of the indeterminate renal mass. This article discusses advantages and some potential pitfalls of spiral CT in the staging of renal cell carcinoma, transitional cell carcinoma, and other renal tumors.

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Both AIDS-related infections and neoplasms of the gastrointestinal tract may be manifest by a clinical picture of acute abdominal disease. Severe abdominal pain may be seen in this population even in the absence of true surgical complications such as perforation, abscess formation, or obstruction. Localizing signs and symptoms are frequently misleading due to underlying immunosuppression, debilitation, and prior or current antibiotic use. CT assumes a critical role in evaluation of the symptomatic AIDS patient, providing evaluation of the entire abdomen and pelvis including lymph nodes, solid viscera, and the bowel itself. CT is thus the modality of choice for characterization of AIDS-related abdominal disease and for direction of appropriate therapy.

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The article presents the computed tomography (CT) findings in 15 patients with histopathologically proven primary lymphoma of the colorectum. CT is invaluable for the characterization of primary colonic lymphomas and for definition of tumor invasion and spread. The lymphomas in our series were categorized according to their CT appearance as either discrete bulky masses (n = 6), focal mural infiltration (n = 5), or diffuse colonic invasion (n = 5). Primary colonic lymphomas that were manifested as mass lesions had a greater depth of mural invasion (x = 4.3 cm) than did infiltrative lesions (x = 2.7 cm, P < .05), and tended to present at an earlier stage. In the setting of solitary mass lesions in the colon that are not associated with adenopathy, CT findings can help to distinguish primary lymphoma from adenocarcinoma. Cecal tumors that grow into the terminal ileum, tumors which are fairly well demarcated from the surrounding pericolonic fat and show no evidence of invasion or obstruction of neighboring viscera, and tumors which perforate in the absence of desmoplastic reaction should suggest lymphoma. A clinical history of human immunodeficiency virus infection should also prompt consideration of colonic lymphoma.

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Spiral CT technology now represents the gold standard in the evaluation of known or suspected pancreatic pathology. For both neoplastic and inflammatory diseases of the pancreas, spiral CT offers many unique advantages over conventional dynamic CT scanning. This article reviews the basic technique and applications of spiral CT in evaluation of the pancreas, with emphasis on its specific advantages.

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Intravenous drug abusers often resort to deep cervical venous access if peripheral access is problematic. Deep cervical injection can occasionally result in needle breakage and needle foreign body. The records of 50 patients with neck needle foreign bodies related to intravenous drug abuse treated at The Johns Hopkins Hospital were reviewed retrospectively. Only half of these patients presented to this hospital with a complaint of a neck needle. Complications related to neck needles were manifested in 5 (10%) of the patients at the time of initial presentation. No delayed complications occurred. Human immunodeficiency virus seropositivity for this group of patients was 77% compared to a rate of 29% for all intravenous drug abusers at the same institution. The demographics and management of neck needle foreign bodies are discussed, and the importance of recognition of neck needle foreign bodies is emphasized.

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We report a case of bacillary angiomatosis involving the liver in addition to multiple cutaneous sites in a patient with AIDS. Abdominal CT demonstrated multiple, small low-attenuation lesions throughout the hepatic parenchyma. Consideration of this entity in the proper clinical setting is essential since it is a readily treatable infection.

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This paper presents the computed tomographic (CT) and barium enema (BE) findings in seven patients with proven primary lymphoma of the colon and rectum. CT and BE examination are complimentary studies in the evaluation of primary lymphoma of the colorectum, and certain relevant findings may be missed when radiographic evaluation does not include both modalities. Both CT and barium studies are very accurate in detecting bulky endoexoenteric tumor masses, although CT may suggest features which can differentiate primary lymphoma from adenocarcinoma. The renal utility of obtaining both a CT and BE examination may lie more in diagnosing complications, such as fistula formation and in the evaluation of subtle infiltrative lesions. While CT is necessary for staging purposes, BE examination may be invaluable for detecting subtle mucosal filling defects which could be missed on CT.

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Spiral or helical computed tomography (CT) allows the rapid acquisition of volumes of CT data in a 24- to 32-s time frame. Rapid data acquisition is accompanied by the ability to reconstruct the images at any pre-determined interval (1-10 mm). This technique is optimal for studies requiring iodinated vascular contrast because it allows data acquisition during the peak contrast levels, optimizing lesion detection. The technique is also excellent for studies that need two- and/or three-dimensional reconstruction as it decreases the chance of interscan motion. Spiral CT has significant potential for a wide range of musculoskeletal imaging applications including in musculoskeletal infection, soft tissue tumors, trauma, and in the oncologic patient.

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This essay illustrates the findings obtained with spiral CT imaging in pancreatic disease. Features of spiral CT--fast scanning, dynamic injection of contrast material allowing optimal vessel opacification, and supplemental multiplanar imaging--promise to provide increased accuracy in the diagnosis and staging of pancreatic disease. With further development of continuous (spiral/helical) scanning technology, this technology should expand to cover a wider range of applications.

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Twenty pediatric patients, aged 2-18 years, with known or suspected masses in the brain and/or spinal cord were studied with magnetic resonance imaging at 0.6T with and without use of 0.1 mmol/kg gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). The multisection, multiecho imaging mode was utilized. Surgically proved mass lesions included astrocytoma (n = 6), medulloblastoma (n = 2), ependymoma (n = 1), craniopharyngioma (n = 1), oligodendroglioma (n = 1), germinoma (n = 1) and fibrosarcoma (n = 1). Presumptive diagnoses included astrocytoma (n = 3), arachnoid cyst (n = 1), tuberous sclerosis (n = 1), cryptic vascular malformation (n = 1), and normal (n = 1). There was dramatic enhancement in 11 of 20 patients, with improved definition of the presence and extent of lesions in six patients. No adverse effects were noted in any of the 20 patients. It is concluded that Gd-DTPA is useful in delineating the presence, extent, and number of certain lesions of the central nervous system in children.

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