Search PubMed⌕ Search

Biomedical subjects

Robert A Halvorsen

Publications and source records attributed to Robert A Halvorsen.

11 recordsLinked to original sources
PubMed2006

Congenital anomalies and normal variants of the pancreaticobiliary tract and the pancreas in adults: part 1, Biliary tract.

OBJECTIVE: The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the biliary tract with contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT. CONCLUSION: Recognizing findings of congenital anomalies and normal variants of the biliary tract at MRCP, MRI, and helical CT, and knowledge of the clinical significance of each entity, are important for establishing a correct diagnosis and in guiding appropriate clinical management.

Adult↗
PubMed2006

Congenital anomalies and normal variants of the pancreaticobiliary tract and the pancreas in adults: part 2, Pancreatic duct and pancreas.

OBJECTIVE: The purpose of this article is to highlight the imaging features of congenital anomalies and normal variants of the pancreatic duct and the pancreas using contemporary imaging techniques such as MR cholangiopancreatography (MRCP), MRI, and helical CT. CONCLUSION: Congenital anomalies and normal variants of the pancreatic duct and the pancreas may be clinically significant and may create a diagnostic challenge. Recognition of the updated imaging features of these entities is important in clinical management and for avoiding misdiagnosis.

Adult↗
PubMed2005

Helical CT evaluation of acute right lower quadrant pain: part I, common mimics of appendicitis.

OBJECTIVE: The purpose of our pictorial essay is to present common mimics of appendicitis as noted on helical CT in patients with right lower quadrant pain and to highlight the features that provide clues to the diagnosis. CONCLUSION: Recognition of the findings of common diseases that simulate acute appendicitis on helical CT, along with features that help to differentiate these entities from appendicitis, is important in establishing a correct diagnosis and in guiding appropriate therapy.

Abdomen, Acute↗
PubMed2005

Helical CT evaluation of acute right lower quadrant pain: part II, uncommon mimics of appendicitis.

OBJECTIVE: The purpose of our pictorial essay is to highlight the helical CT features of uncommon mimics of appendicitis and to provide clues to differentiate them from appendicitis. CONCLUSION: Uncommon mimics of appendicitis create a diagnostic challenge in patients with right lower quadrant pain. Recognition of the helical CT features of uncommon mimics of appendicitis is important in clinical management and avoiding unnecessary laparotomy.

Abdomen, Acute↗
PubMed2004

Vascular tumors of the abdominal wall.

BACKGROUND: Vascular tumors of the abdominal wall are rare, benign congenital malformations that may cause pain or cosmetic disfigurement and are of significance for their ability to mimic more clinically aggressive tumors. There have been no previous reports of vascular tumors of the abdominal wall. This investigation reports the clinical presentation, diagnosis, and treatment of three patients with vascular tumors of the abdominal wall. METHODS: Magnetic resonance angiography (MRA) was used to identify feeding and draining vessels and to aid in operative planning for two patients; in a third patient, standard magnetic resonance imaging revealed the feeding vessels. RESULTS: MRA accurately identified the feeding and draining vessels and aided in operative planning, thus facilitating complete tumor resection. To date, patients have not experienced tumor recurrence. CONCLUSIONS: These cases suggest that MRA can be employed as a noninvasive imaging technique and should be the standard preoperative modality to plan the operative approach to vascular tumors of the abdominal wall.

Abdominal Wall↗
PubMed2004

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study.

BACKGROUND: The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood. METHODS: Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated. RESULTS: A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%. CONCLUSIONS: Air-contrast barium enema accurately detects colon cancer and diverticula. Its sensitivity for detection of polypoid lesions or adenomas is poor and was confounded by the presence of diverticula.

Adenomatous Polyps↗
PubMed2003

Computerized tomographic colonography: performance evaluation in a retrospective multicenter setting.

BACKGROUND & AIMS: No multicenter study has been reported evaluating the performance and interobserver variability of computerized tomographic colonography. The aim of this study was to assess the accuracy of computerized tomographic colonography for detecting clinically important colorectal neoplasia (polyps >or=10 mm in diameter) in a multi-institutional study. METHODS: A retrospective study was developed from 341 patients who had computerized tomographic colonography and colonoscopy among 8 medical centers. Colonoscopy and pathology reports provided the standard. A random sample of 117 patients, stratified by criterion standard, was requested. Ninety-three patients were included (47% with polyps >or=10 mm; mean age, 62 years; 56% men; 84% white; 40% reported colorectal symptoms; 74% at increased risk for colorectal cancer). Eighteen radiologists blinded to the criterion standard interpreted computerized tomography colonography examinations, each using 2 of 3 different software display platforms. RESULTS: The average area under the receiver operating characteristic curve for identifying patients with at least 1 lesion >or=10 mm was 0.80 (95% lower confidence bound, 0.74). The average sensitivity and specificity were 75% (95% lower confidence bound, 68%) and 73% (95% lower confidence bound, 66%), respectively. Per-polyp sensitivity was 75%. A trend was observed for better performance with more observer experience. There was no difference in performance across software display platforms. CONCLUSIONS: Computerized tomographic colonography performance compared favorably with reported performance of fecal occult blood testing, flexible sigmoidoscopy, and barium enema. A prospective study evaluating the performance of computerized tomography colonography in a screening population is indicated.

Colonic Neoplasms↗
PubMed2002

Blunt trauma to the gastrointestinal tract: CT findings with small bowel and colon injuries.

The CT diagnosis of bowel injury is difficult and warrants an organized approach. Careful scrutiny of CT images for extraluminal gas or fluid and bowel wall thickening is required. Review of images of the entire abdomen and pelvis using lung window settings is recommended, followed by the analysis using soft tissue window settings. Specific search for extraluminal fluid collections with a triangular or matted appearance will help detect bowel injury.

Journal Article↗
PubMed2002

Increased thymic mass and circulating naive CD4 T cells in HIV-1-infected adults treated with growth hormone.

OBJECTIVE: To determine whether treatment with growth hormone (GH) enhances thymopoiesis in individuals infected with HIV-1. METHODS: Five HIV-1-infected adults were treated with GH for 6-12 months in a prospective open-label study. Immunological analyses were performed before GH treatment and repeated at 3 month intervals after GH initiation. Thymic mass was analysed using computed tomography with quantitative density and volume analysis. Analysis of circulating lymphocytes, including naive and memory T cell subsets, was performed using multiparameter flow cytometry. RESULTS: GH treatment was associated with a marked increase in thymic mass in all GH recipients. Circulating naive CD4 T cells also increased significantly in all patients during GH therapy, suggesting an enhancement of thymopoiesis. CONCLUSION: GH has significant effects on the human immune system, including the reversal of thymic atrophy in HIV-1-infected adults. De-novo T cell production may thus be inducible in immunodeficient adults.

Adult↗
PubMedDate not supplied

Bronchobiliary fistula after liver transplantation.

This report describes the imaging findings of the first reported case of a bronchobiliary fistula that developed as a complication of liver transplantation. The diagnosis was confirmed by the aspiration of bile from the bronchus.

Adult↗