Robert A Halvorsen

Robert A Halvorsen
Virginia Commonwealth University | VCU · Department of Radiology

MD

About

175
Publications
33,713
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
7,183
Citations

Publications

Publications (175)
Article
Purpose: We aimed to determine which intravenous contrast-enhanced multidetector computed tomography (MDCT) protocol produced the most accurate results for the detection of splenic vascular injury in hemodynamically stable patients who had sustained blunt abdominal trauma. Methods: We retrospectively reviewed 88 patients from 2003 to 2011 who su...
Article
Full-text available
PET/CT with the glucose analogue (18)F-fluorodeoxyglucose ((18)F-FDG) has several potential applications for monitoring tumor response to therapy in patients with non-small cell lung cancer (NSCLC). A prerequisite for many of these applications is detailed knowledge of the repeatability of quantitative parameters derived from (18)F-FDG PET/CT studi...
Article
Full-text available
Objective: The purpose of this study was to determine the prevalence of nonpolypoid adenomas and the sensitivity of CT colonography (CTC) in their detection by use of the restricted criteria of height-to-width ratio<50% and height elevation≤3 mm. Materials and methods: In the National CT Colonography Trial (American College of Radiology Imaging...
Chapter
Imaging of the esophagus is most frequently performed as a component of an imaging study that is primarily designed to evaluate extraesophageal anatomy, such as during a cardiac MRI or chest CT to rule out pulmonary embolism. However, imaging of the esophagus may be designed primarily to evaluate esophageal pathology. When CT and MRI studies are pe...
Chapter
Primary carcinoma of the esophagus includes squamous cell carcinoma and adenocarcinoma (typically arising in Barrett’s esophagus). Carcinoma of the esophagus represents 7% of all cancers of the gastrointestinal tract (Levine and Halvorsen 2008). Historically, the majority of esophageal malignancies represented squamous cell carcinomas (90–95%); how...
Article
Full-text available
To conduct post-hoc analysis of National CT Colonography Trial data and compare the sensitivity and specificity of computed tomographic (CT) colonography in participants younger than 65 years with those in participants aged 65 years and older. Of 2600 asymptomatic participants recruited at 15 centers for the trial, 497 were 65 years of age or older...
Article
Full-text available
The purpose of our study was to compare the effect of three different full-laxative bowel preparations on patient compliance, residual stool and fluid, reader confidence, and polyp detection at CT colonography (CTC). A total of 2531 patients underwent CTC followed by colonoscopy for the American College of Radiology Imaging Network (ACRIN) National...
Article
Full-text available
To determine whether the reader's preference for a primary two-dimensional (2D) or three-dimensional (3D) computed tomographic (CT) colonographic interpretation method affects performance when using each technique. In this institutional review board-approved, HIPAA-compliant study, images from 2531 CT colonographic examinations were interpreted by...
Article
Multidetector computed tomography (MDCT) has emerged as the imaging modality of choice for evaluating the abdomen and pelvis in trauma patients. MDCT readily detects injury of the solid organs as well as direct and indirect features of bowel and/or mesenteric injury-an important advance given that unrecognized bowel and mesenteric injuries may resu...
Article
To retrospectively determine the frequency and importance of a small amount of isolated pelvic free fluid seen at multidetector computed tomography (CT) in male patients who have blunt trauma without an identifiable cause. Institutional review board approval was obtained, and the requirement for informed consent was waived for this HIPAA-compliant...
Article
Full-text available
The objective of this article is to describe the experience of the National CT Colonography Trial with radiologist training and qualification testing at CT colonography (CTC) and to correlate this experience with subsequent performance in a prospective screening study. Ten inexperienced radiologists participated in a 1-day educational course, durin...
Article
ABSTRACT Although recognition and curative treatment of both precursor adenomas and localized cancers are possible through early-detection, and regular screening reduces mortality from colorectal cancer, screening is largely underused. Reasons for underuse include performance drawbacks and issues of comfort, availability, and expense. Computed tomo...
Conference Paper
PURPOSE To determine the spectrum of findings of active extravasation on contrast-enhanced MDCT (indicating active bleeding), and correlate with the findings at digital subtraction angiography (DSA). METHOD AND MATERIALS We conducted a retrospective review of the findings of active extravasation in 42 patients with blunt abdominal trauma who under...
Article
Full-text available
Computed tomographic (CT) colonography is a noninvasive option in screening for colorectal cancer. However, its accuracy as a screening tool in asymptomatic adults has not been well defined. We recruited 2600 asymptomatic study participants, 50 years of age or older, at 15 study centers. CT colonographic images were acquired with the use of standar...
Chapter
Trauma is a significant public health problem, representing the third leading cause of death in the United States. Trauma is also the leading cause of mortality in Americans under the age of 40. With the widespread availability of multidetector-row computed tomography (MDCT) in trauma centers, the traditional workup of trauma patients has changed....
Article
To retrospectively evaluate if false-negative interpretations at computed tomographic (CT) colonography are due to observer error. This study was HIPAA compliant and had institutional review board approval, with waiver of informed consent. An initial unblinded review of CT colonographic image data was used to generate reconciliation reports for all...
Article
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 MRC...
Article
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...
Article
Patient experience varies with the currently available colon imaging tests, including air contrast barium enema, computed tomographic colonography, and colonoscopy. We examined differences in patient experience with colon imaging tests and whether they varied with gender, age, and race. Patients with fecal occult blood, hematochezia, iron-deficienc...
Conference Paper
LEARNING OBJECTIVES 1) To describe the patterns of disease associated with esophagitis (including reflux esophagitis, infectious esophagitis, and drug-induced esophagitis) and esophageal strictures on double-contrast esophagography. 2) To describe the various findings of esophageal neoplasms on barium studies, CT, and other imaging modalities. 3) T...
Conference Paper
PURPOSE Our recent computed tomographic colonography (CTC) trial reported a lower sensitivity for lesion detection than in several previous trials. We therefore aimed to understand the reasons that lesions were not detected by analyzing false negative (FN) cases. METHODS We retrospectively reviewed, using both 2D and 3D analysis, the 228 lesions gr...
Article
Full-text available
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 unco...
Article
The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests. Patients with faecal occult blood, haematochezia, iron-deficiency anaemia,...
Article
Patients with acquired immunodeficiency syndrome are at risk of developing opportunistic infections and aggressive tumors. Computed tomographic examination is the usual method of evaluating the abdomen and pelvis in these patients. Although this technique is reasonably sensitive in detecting pathology, findings are often nonspecific. A case of hepa...
Article
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...
Conference Paper
LEARNING OBJECTIVES 1) To describe the patterns of disease associated with esophagitis (including reflux esophagitis, infectious esophagitis, and drug-induced esophagitis) and esophageal strictures on double-contrast esophagography. 2) To describe the various findings of esophageal neoplasms on barium studies, CT, and other imaging modalities. 3) T...
Article
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.
Article
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, diagno...
Article
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. A r...
Article
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...
Article
To determine whether treatment with growth hormone (GH) enhances thymopoiesis in individuals infected with HIV-1. 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...
Article
To characterize immune phenotype and thymic function in HIV-1-infected adults with excellent virologic and poor immunologic responses to highly active antiretroviral therapy (HAART). Cross-sectional study of patients with CD4 T cell rises of > or = 200 x 10(6) cells/l (CD4 responders; n = 10) or < 100 x 10(6) cells/l (poor responders; n = 12) in th...
Article
Full-text available
GH has been proposed as a therapy for patients with HIV-associated fat accumulation, but the pharmacological doses (6 mg/d) used have been associated with impaired fasting glucose and hyperglycemia. In contrast, physiologic doses of GH ( approximately 1 mg/d) in HIV-negative men reduced visceral adiposity and eventually improved insulin sensitivity...
Article
Physical discomfort, anxiety, embarrassment, and other aspects of patient experience impact on future compliance for colonic imaging tests. Therefore, a prospective study was performed comparing patient experiences during air contrast barium enema (ACBE), flexible sigmoidoscopy, and colonoscopy. Immediately after each procedure, patients completed...
Article
Therapy with HIV protease inhibitors (PI) has been associated with hyperglycemia, hyperlipidemia and changes in body composition. It is unclear whether these adverse effects are drug related, involve an interaction with the host response to HIV or reflect changes in body composition. Indinavir 800 mg twice daily was given to 10 HIV-seronegative hea...
Article
Endoscopic sonography (EUS) is an important imaging modality for evaluating benign and malignant luminal gastrointestinal-tract abnormalities. The objectives of this study were to evaluate the feasibility of catheter-based EUS (C-EUS) during standard upper and lower endoscopy in patients with malignancies and other abnormalities of the gastrointest...
Article
Cinematic technetium Tc 99m red blood cell ((99m)Tc-RBC) scans, in which real-time scanning is performed and analyzed, can accurately localize gastrointestinal bleeding and thus direct selective surgical intervention. Retrospective medical record review with historical controls. Large, university-affiliated public hospital in urban setting. Twenty-...
Article
Full-text available
HIV-1 disease is associated with pathological effects on T-cell production, destruction, and distribution. Using the deuterated (2H) glucose method for endogenous labeling, we have analyzed host factors that influence T-cell turnover in HIV-1-uninfected and -infected humans. In untreated HIV-1 disease, the average half life of circulating T cells w...
Article
To determine whether the computed tomographic (CT) appearances of multiple pulmonary nodules in patients with acquired immunodeficiency syndrome (AIDS) can help differentiate the potential infectious and neoplastic causes. The thoracic CT scans obtained in 60 patients with AIDS and multiple pulmonary nodules were reviewed retrospectively by two tho...
Article
The detection of isolated intestinal injuries after blunt trauma can be difficult because of subtle signs and symptoms, often leading to delayed diagnosis. We hypothesized that specific clinical indicators could be identified to assist in the diagnosis of these injuries. Medical records of all patients with such injuries from 1988 to 1996 were revi...
Article
Gastrointestinal disorders are common causes of acute disease in AIDS patients, second only to pulmonary pathology. Abdominal disorders are often evaluated by computed tomography (CT). The abnormalities encountered on CT are produced by a variety of opportunistic infections and neoplasms and can be confusing. This article describes a pattern approa...
Article
The efficacy of CT and color Doppler ultrasound in the assessment of intestinal and mesenteric ischemia was the subject of several reports in the past year's literature. The utility of CT in evaluating small bowel obstruction continues to be a focus of attention, as do the CT manifestations of small bowel and mesenteric injury following blunt traum...
Article
Esophageal carcinoma remains a devastating malignancy. Patients typically present clinically with dysphagia, which implies compromise of the esophageal lumen; therefore, advanced tumor often is found. Lymphatic drainage of the esophagus takes pluce via an extensive lymphatic network, and early and widespread metastasis occurs frequently. The esopha...
Article
The biphasic upper gastrointestinal examination using barium and gas distention of the stomach is approximately as accurate as endoscopy in the detection of gastric cancer. Endoscopy allows biopsy of suspicious lesions but is more invasive and costly. The barium examination can reliably differentiate gastric ulcers into three categories: benign, ma...
Article
Full-text available
The purpose of this study was to determine the diagnostic sensitivity and specificity of CT in detecting acute rupture of the diaphragm after blunt trauma. Abdominal CT scans taken before surgery of 11 patients with diaphragmatic rupture (eight left and three right) and 21 patients with intact diaphragms after major acute blunt abdominal trauma wer...
Article
The literature pertaining to small bowel imaging in the past year once again emphasizes the utility of cross-sectional imaging techniques in small bowel obstruction, inflammatory bowel disease, and in trauma to the bowel and mesentery. The efficacy of enteroclysis for evaluating patients with obscure gastrointestinal bleeding was addressed by multi...
Article
Full-text available
The purpose of this study was to determine the CT features of cytomegalovirus colitis in patients with AIDS. Abdominal CT scans of 24 patients with biopsy-proved cytomegalovirus colitis (colonoscopy, n = 14; sigmoidoscopy, n = 8; surgery, n = 2) were jointly reviewed by two observers. Patients were men 26-68 years old (mean age, 39 years; SD, 9 yea...
Article
Alagille's syndrome, also called arteriohepatic dysplasia, is a congenital anomaly consisting of hepatic, ocular, skeletal, and cardiac anomalies. The abdominal imaging findings were reviewed in eight patients with biopsy-proven Alagille's syndrome. One patient also had coexistent hepatocellular carcinoma. Seven right upper quadrant sonograms, six...
Article
The literature pertaining to small bowel imaging in the past year stresses the use of cross-sectional imaging techniques in the evaluation of small bowel obstruction, gastrointestinal neoplasm, inflammatory bowel disease, and trauma to the intestine and mesentery. In particular, the greater sensitivity of computed tomography relative to conventiona...
Article
Thickening of the gastrointestinal bowel wall is commonly identified by abdominal computed tomographic (CT) imaging. The objective of this study was to prospectively determine the prevalence of substantial pathological abnormalities in patients with bowel wall thickening by computed tomography. Consecutive patients with bowel wall (gastric, duodena...
Article
CT and EUS are complimentary modalitiesthat allow accurate esophageal cancer staging. To prevent unnecessary surgical interventions, patients should undergo selective imaging tests before curative resection is attempted or palliative protocols are implemented (Fig 6). An acceptable strategy for evaluating a newly diagnosed esophageal cancer patient...
Article
Patients subjected to trauma to the abdomen and pelvis suffer a wide variety of injuries, many of which can be detected by computed tomography (CT). This article provides a rigorous step-by-step routine useful in the interpretation of these studies, in order to decrease the number of missed traumatic lesions. The routine includes: search for pneumo...
Article
Neoplasms of the upper gastrointestinal tract are generally detected by barium studies or endoscopy. Computed tomography remains the primary imaging modality for staging. Magnetic resonance imaging and endoscopic ultrasonography may also play an increasing role in evaluating these tumors.
Article
The year 1991 was a year of innovation, with interesting papers published in the imaging as well as the medical and surgical literature. Several reports described novel techniques using transcutaneous ultrasound to evaluate the swallowing mechanism; another used CT and ultrasound of the neck for staging esophageal carcinoma. The new field of endosc...
Article
This study addresses the theoretical, experimental, and clinical application of using a central venous catheter system (CVS) for the rapid injection of contrast media during computed tomography (CT). Application of Poiseuille's law and the Reynolds equation yielded theoretical data. In-line pressures were measured in experimental models and patient...
Article
A prospective longitudinal study of chest-wall deformity after tissue expansion for breast reconstruction was performed in 19 women. CT imaging was a sensitive method for detecting occult deformity. Using a semiquantitative scale for measuring deformity, all patients and 94 percent of expanders had some thoracic abnormality after tissue expansion....
Article
Full-text available
The preoperative detection of peritoneal metastases from gynecologic malignancies is difficult; in particular, CT often fails to detect peritoneal implants. This study was designed to determine if the administration of intraperitoneal iodinated contrast media would increase the CT detection of such peritoneal metastases. Prospectively, both standar...
Article
In the past year there have been an unusual number of new concepts developed concerning the pharynx and the esophagus. The normal swallowing mechanism has been studied in detail using a variety of techniques that have increased our understanding of the normal and abnormal swallowing mechanism. In the esophagus, simultaneous barium swallows and esop...
Article
Patients who have had prior reactions to iodinated contrast material have increased risk for repeat reactions. Nonionic contrast agents have been reported to reduce the risk of contrast reactions. A multicenter study was undertaken to determine the repeat reaction rate using iohexol. Two hundred ninety-one repeat reactors were included in the study...
Article
A serious and often fatal complication of heart-lung transplantation is the development of obliterative bronchiolitis (OB). Currently the screening for OB is based on symptoms, pulmonary function tests, and transbronchial biopsies. The chest radiographs are often normal with OB. Obliterative bronchiolitis produces luminal narrowing of both bronchio...
Article
Either CT or MRI can be used as a primary screening test for liver masses in a patient with a known or suspected malignancy. A number of variations in techniques are available for both CT and MRI, and combinations of these techniques are often required to increase the detectability rate for hepatic lesions. Whether CT or MRI is chosen as an initial...
Article
A 50-year-old woman with Felty's syndrome, who presented with "menopausal" symptoms, was found to have a large pelvic mass on physical exam. Computed tomography of the pelvis led to an incorrect diagnosis of malignancy, while radionuclide imaging using Tc-99m sulfur colloid confirmed the diagnosis of ectopic splenomegaly.
Article
The number of imaging modalities available to stage and follow-up patients with primary neoplasms of the gastrointestinal (GI) tract continues to increase. Magnetic resonance imaging (MRI), computed tomography (CT), and ultrasonography are useful techniques for both staging and follow-up. For staging, CT is most frequently used for the detection of...
Article
A 50-year-old woman with Felty's syndrome, who presented with "menopausal" symptoms, was found to have a large pelvic mass on physical exam. Computed tomography of the pelvis led to an incorrect diagnosis of malignancy, while radionuclide imaging using Tc-99m sulfur colloid confirmed the diagnosis of ectopic splenomegaly.
Article
Full-text available
Leakage from the urinary bladder or duodenal stump after pancreas transplantation with urinary bladder drainage of the graft is difficult to diagnose clinically. We retrospectively reviewed our experience with fluoroscopic cystography and CT to determine their relative merit in the diagnosis of pancreatic fluid and urine leakage as documented by su...
Article
Focal fatty metamorphosis of the liver is a well-recognized entity characteristically demonstrated by a nonspherical, low-density area without mass effect. We present a case of focal fatty metamorphosis of the liver that shows multiple areas of low attenuation within the liver with mass effect. Radionuclide liver-spleen scan shows multiple focal de...
Article
Air in the heart is a serious condition and may be life-threatening. It is usually of iatrogenic origin or the result of trauma. Computed tomography of a heart-lung transplant recipient who had unilateral hydropneumothorax revealed a mediastinal gas collection that appeared to be intracardiac. A follow-up study with intrapleural contrast medium rev...
Article
Cytomegalovirus (CMV) is a frequent pathogen of the respiratory tract in immunosuppressed patients. The diagnosis of CMV pneumonia frequently requires bronchopulmonary lavage or lung biopsy because the findings on chest radiographs are nonspecific. In only three cases of pure CMV pneumonia has the computed tomography (CT) appearance been described....
Article
The ability of computed tomography (CT) to detect metastatic lesions in adrenal glands was evaluated on 91 autopsied lung cancer patients who died in 11 hospitals in the eastern United States and Canada from January 1983 to February 1988. Abdominal CT scans within 90 days of death were reviewed twice by two radiologists blinded to the autopsy diagn...
Article
This review covers articles relating to the pharynx and the esophagus, including publications in the imaging literature, as well as the medical and surgical literature of interest to radiologists. The review is divided into sections discussing methodology, the pharynx, and the esophagus. Because the majority of the articles reviewed relate to the e...
Article
The computed tomographic (CT) findings in pancreas transplant rejection have been reported to include graft swelling and inhomogeneity. We report a patient with transplant rejection in whom the preoperative CT examination and specimen radiographs revealed large cystic structures within the pancreas. Cystic central necrosis has previously been repor...

Network