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Biomedical subjects

A J Megibow

Publications and source records attributed to A J Megibow.

At least 19 recordsLinked to original sources
PubMed2004

Gastrointestinal infection in the immunocompromised (AIDS) patient.

In the past two decades acquired immunodeficiency syndrome (AIDS) has become one of the most devastating illnesses in human history. As the epidemic continues to spread increasingly, AIDS patients are no longer confined to a few specialized AIDS hospitals and are now seen in general hospitals and clinics everywhere. Radiologists need to recognize the appearances, to understand how-safely-to care for patients with this disease, and to know enough about the illness to be able to counsel their patients. This article presents a review of current knowledge about the wide range of gastrointestinal hepatic, splenic, biliary, and retroperitoneal manifestations in AIDS, and how the role of modern medical imaging techniques and diagnosis and treatment can be applied. The imaging aspects (conventional double-contrast gastrointestinal studies, ultrasound, CT, and MR) of the diseases of the luminal gastrointestinal tract, liver, spleen, biliary tract, and retroperitoneum will be systematically discussed. Candidiasis, herpes, cytomegalovirus, cryptosporidiosis, histoplasmosis, isosporiasis, salmonellosis, toxoplasmosis, unusual mycobacteria, and viral infections account for the majority of non-neoplastic disorders.

AIDS-Related Opportunistic Infections↗
PubMed2002

Spiral computed tomography assessment of resectability of pancreatic ductal adenocarcinoma: analysis of results.

BACKGROUND: Despite more recent technical advances, single detector spiral computed tomography is still the most widely used imaging technique for the detection and staging of pancreatic adenocarcinoma. Many reports have recently focused on single detector spiral computed tomography imaging findings indicative of unresectability AIM: To evaluate the ability of single detector spiral computed tomography in the pre-operative staging of ductal adenocarcinoma of the pancreas in selecting surgically resectable versus unresectable cases, considering different parameters (vascular and local infiltration, liver metastases, lymphadenopathy, and peritoneal carcinomatosis). PATIENTS AND METHODS: A total of 100 patients diagnosed with ductal adenocarcinoma of the pancreas, pathologically verified, and examined with single detector spiral computed tomography were considered. Of these, 63 underwent surgery; 37 were excluded (imaging evidence of unresectability in biopsy-proven adenocarcinomas). Single detector spiral computed tomography studies, performed at the time of surgery, were retrospectively reviewed by two radiologists. The final results were reached by consensus, without being aware of the operation. All prospective clinical readings were also considered, and tabulated. RESULTS: In the patients undergoing surgery, 44 proved to be unresectable and 19 resectable. Considering the above-mentioned parameters, the prospective assessment of resectability demonstrated a rather low sensitivity (68%), with high specificity (95%). Accordingly, a high positive predictive value (97%) was achieved, while the negative predictive value was 56%. After the retrospective evaluation, the value of sensitivity increased (84%) to the expense of the specificity (84%). Moreover, a positive predictive value of 92.5%, and a negative predictive value of 69.5% were obtained. CONCLUSIONS: The demonstration of many signs of unresectability of pancreatic ductal adenocarcinoma reported in the literature yields a better sensitivity in the diagnosis, but unfortunately, is associated with an inevitable reduction in specificity.

Adenocarcinoma↗
PubMed2001

MR imaging of the pancreas.

Current MR imaging technology offers the surgeon diagnostic information about pancreatic diseases. This article reviews the basics of MR imaging formation and the rationale for the different types of imaging sequences that comprise a comprehensive pancreaticobiliary examination. Clinical examples include evaluation of pancreatic neoplasms, acute and chronic pancreatitis, and congenital abnormalities.

Acute Disease↗
PubMed2001

Cystic tumors of the pancreas: the radiologist.

In this article, the author reviews the effect of contemporary imaging techniques on the diagnosis of various pancreatic neoplasms. Histologic detail and the relationship to other means of diagnosis are included.

Adenocarcinoma, Mucinous↗
PubMed2001

Acute appendicitis: comparison of helical CT diagnosis focused technique with oral contrast material versus nonfocused technique with oral and intravenous contrast material.

PURPOSE: To compare the diagnostic accuracy of focused helical computed tomography (CT) with orally administered contrast material with that of nonfocused helical CT with orally and intravenously administered contrast material. MATERIALS AND METHODS: After receiving oral contrast material, 228 patients with clinically suspected appendicitis underwent focused appendiceal CT (5-mm section thickness, 15-cm coverage in the right lower quadrant). Immediately thereafter, helical CT of the entire abdomen and pelvis was performed following intravenous administration of contrast material (abdomen, 7-mm section thickness; pelvis, 5-mm section thickness). Studies were separated and independently interpreted by three observers who were blinded to patient names. Diagnoses were established by means of surgical and/or clinical follow-up findings. RESULTS: Fifty-one (22.4%) of 228 patients had acute appendicitis. Readers diagnosed appendicitis with 83.3%, 73.8%, and 71.4% sensitivity and 93.0%, 92.3%, and 97.9% specificity with focused nonenhanced appendiceal CT. Readers diagnosed appendicitis with 92.9%, 92.9%, and 88.1% sensitivity and 93.7%, 95.1%, and 96.5% specificity with nonfocused enhanced CT. Summary areas under the receiver operating characteristic curve estimates for focused nonenhanced and nonfocused enhanced CT were 0.916 and 0.964, respectively; the differences were statistically significant (P <.05) for two of three readers. All readers demonstrated higher sensitivities for detecting the inflamed appendix with nonfocused enhanced CT. Appendicitis was missed with focused CT in two patients whose inflamed appendix was not included in the imaging of the right lower quadrant. All readers were significantly more confident in diagnosing alternative conditions with nonfocused enhanced CT. CONCLUSION: Diagnostic accuracy of helical CT for acute appendicitis improved significantly with use of intravenous contrast material.

Acute Disease↗
PubMed2001

Effect of different bowel preparations on residual fluid at CT colonography.

The effect of different bowel preparations on residual fluid during computed tomographic (CT) colonography was evaluated. Forty-two patients received either a polyethylene glycol electrolyte solution preparation or a phospho-soda preparation the day prior to CT colonography. The amount of residual fluid was calculated for each patient. On average, a phospho-soda preparation provided significantly less residual fluid than a polyethylene glycol electrolyte solution preparation.

Aged↗
PubMed2001

Infrarenal abdominal aortic aneurysms at multi-detector row CT angiography: intravascular enhancement without a timing acquisition.

In 70 patients referred for evaluation of aortoiliac aneurysm disease, multi-detector row computed tomography was performed with a uniform 25-second delay from the initiation of intravenous administration of a 150-mL bolus of contrast material at 4 mL/sec. In all patients, adequate enhancement (>200 HU) of the aorta and intense enhancement of iliofemoral runoff was achieved without venous contamination.

Aged↗
PubMed2001

Quantitative and qualitative evaluation of volume of low osmolality contrast medium needed for routine helical abdominal CT.

OBJECTIVE: The purpose of our study was to determine the minimum optimal dose of IV contrast medium for helical CT that can preserve image quality while reducing cost. SUBJECTS AND METHODS: Four hundred sixty-three patients from six centers were enrolled in a prospective trial in which patients were randomized into one of four weight-based dose categories of iopromide, 300 mg I/mL: 1.25, 1.50, 1.75, and 2.0 mL/kg. Six of 463 patients were excluded from analysis. A radiologist at each center who was unaware of the volume of contrast medium administered determined whether the scans were acceptable. The responses were analyzed by dose, in aggregate, and by weight. Enhancement values (in Hounsfield units) in regions of interest in the liver, pancreas, aorta, and kidneys were obtained at a single time during the scan. The participating radiologist was unaware of these values. Finally, three additional nonparticipating site observers assessed the images for acceptability, diagnostic quality, and overall level of confidence. A cost model comparing incurred charges in using 150 or 100 mL, or 1.5 mL/kg, of low osmolality contrast medium was developed from experience in an additional 303 patients. RESULTS: We found no clinically significant difference in acceptability of scans at doses greater than 1.5 mL/kg. However, significant variability occurred among the centers. The use of 1.5 mL/kg led to a savings of $9927.16 for 303 patients when compared with the use of 150 mL at list price. The cost is the same for 1.5 mL/kg or use of 100 mL of contrast medium. CONCLUSION: A weight-based dose at 1.5 mL/kg of low osmolality contrast medium can provide acceptable scans in most patients, with a significant cost savings.

Body Weight↗
PubMed2000

Comparison of time-efficient CT colonography with two- and three-dimensional colonic evaluation for detecting colorectal polyps.

OBJECTIVE: We compared the findings of time-efficient CT colonography with complete two-dimensional (2D) and three-dimensional (3D) CT colonography and conventional colonoscopy in detecting colorectal polyps. SUBJECTS AND METHODS: Forty-two patients undergoing colonoscopy screening were examined with CT colonography before endoscopy. Data were examined following one of two methods. In method 1, axial 2D data sets were examined in a cine mode. If findings were suggestive of abnormality, focal areas were examined with 3D CT colonography. In method 2, data sets were examined exactly as in method 1, and subsequent to that review, data sets were examined with simultaneous 3D "fly-through" CT colonography (surface-rendered images) and multiplanar reformatted images. The time required to examine CT colonography using each technique was recorded and abnormal findings were documented. Results of methods 1 and 2 were compared with findings on colonoscopy. RESULTS: Colonoscopy detected 16 polyps in 13 patients (polyp size, 2-10 mm). Ten polyps measured 5 mm or less, five measured between 6 and 9 mm, and one measured 10 mm or more. Using method 1, two of 10 polyps measuring less than 5 mm, three of five polyps measuring between 6 and 9 mm, and one polyp measuring 10 mm were detected. We noted no false-positive polyps. Average evaluation time was 16 min. With method 2, the same polyps were seen as with method 1. No additional polyps were detected, and the average evaluation time was 40 min. CONCLUSION: Axial 2D CT colonography can be performed quickly and is comparable with complete 2D and 3D CT colonography in detecting colorectal polyps.

Aged↗