Biomedical subjects

D P Atkinson

Publications and source records attributed to D P Atkinson.

5 recordsLinked to original sources

PubMed1996

Two-dimensional coronary MRA: limitations and artifacts.

Our purpose was to assess image quality and interpretation problems of two-dimensional (2D) coronary MR angiograms. The coronary arteries of 27 subjects (12 normal volunteers and 15 patients) were evaluated with 2D coronary MR angiography (MRA). Coronary MRA was performed with a fat-suppressed electrocardiographically gated breath-hold gradient-echo sequence with k-space segmentation using a 1.5-T imager. Image quality throughout the study was occasionally degraded by: image ghosting (22%), ringing (19%), and/or blurring (22%) and incomplete fat-suppression (19%). Intermittent difficulties with breathholding were encountered in 44% of subjects. When limiting the analysis to those images with optimal image quality, interpretative difficulties were sometimes found: misregistration due to inconsistent breathholding (37%); difficulty in distinguishing veins from arteries (37%); obscured anatomy due to overlapping structures (26%); and poor visualization of portions of the left main coronary artery (59%). Two-dimensional coronary MRA studies have image quality and interpretive problems which need to be understood and addressed before routine clinical scanning is initiated.

Adult↗

PubMed1992

Indium-111 monoclonal antibody B72.3 scintigraphy in colorectal cancer. Correlation with computed tomography, surgery, histopathology, immunohistology, and human immune response.

As part of an open-labeled nonrandomized multi-institutional Phase III study, the authors compared the results of In-111 (In-111) B72.3 glycyl-tyrosyl-n-diethylenetriaminepentaacetic acid lysine (GYK-DTPA) monoclonal antibody scintigraphy with computed tomography (CT), surgery, histopathology, immunohistology, and human antibody response in 23 patients with primary colorectal carcinoma. There were no significant adverse reactions to 1 mg of In-111-labeled antibody. Planar imaging identified 16 of 23 primary colon lesions, whereas single photon emission computer tomography (SPECT) imaging identified 21. SPECT also correctly identified lymphatic involvement in four patients. (There were two false-positive results.) Liver metastases were identified with SPECT imaging. Twenty-six percent of patients developed human anti-mouse antibody (HAMA). These preliminary results demonstrate that In-111 B72.3 GYK-DTPA is a safe monoclonal antibody conjugate that has a high sensitivity for identifying primary colorectal cancer. Regional lymphatic and distant liver metastases also can be imaged, but false-positive results can occur.

Adenocarcinoma↗

PubMed1984

Elective carotid resection for squamous cell carcinoma of the head and neck.

Patients with squamous cell carcinoma adherent to the carotid artery have a very poor prognosis, but some can be salvaged by aggressive surgical resection. Preoperative four vessel arteriography with intracranial views is mandatory to detect coexisting arteriosclerotic disease which may limit collateral perfusion of the ipsilateral cerebral hemisphere. Matas-type occlusive tests performed preoperatively are potentially dangerous and do not provide quantitative information that can be obtained intraoperatively by measuring internal carotid artery stump pressures. If the stump pressure is 50 mm Hg or greater, carotid reconstruction is unnecessary. A stump pressure of less than 50 mm Hg is an indication for reconstruction if the pharynx has not been entered during resection. If mucosal entry will be necessary and the stump pressure is less than 50 mm Hg, resection should not be carried out because of the increased risk of graft complications. Somatosensory evoked potentials predict cerebral tolerance to temporary interruption of flow but do not necessarily predict tolerance to permanent interruption of flow. Autogenous vein is the graft material of choice for reconstruction. In those patients not reconstructed, low-dose heparinization started before operation and continued for 10 days may lessen the likelihood of delayed stroke from embolization of a propagated thrombus in the carotid stump.

Adult↗

PubMed1982

Modified bilobular ("gemini") pectoralis major myocutaneous flap.

The bilobular or gemini type of pectoralis major myocutaneous flap evolved from a desire to simplify the closure of large surgical defects of both mucosa and skin that could not be satisfactorily closed primarily. Previously, such defects often required combined or multiple reconstructive procedures such as myocutaneous and deltopectoral flap operations. The mucosal and skin defects are closed by two skin paddles supported by a single muscular vascular pedicle. The skin paddles are fashioned side by side and separated from each other as the muscle is folded between them parallel to the vascular axis. All of the defects were successfully closed and the major portion of all grafts survived. This operation permits single-stage reconstruction after ablation of tumors or treatment of complications which produced large through-and-through mucocutaneous defects of the head and neck area.

Adult↗

PubMedDate not supplied

Coronary MR angiography during peak-systole: work in progress.

The purpose of this study is to compare the quality of images of coronary arteries obtained with two-dimensional breath-hold coronary MR angiography during peak systole and mid diastole. Two-dimensional coronary MR angiography was performed in eight normal volunteers at peak systole and in mid diastole with a commercial 1.5-T MR imager. An ultrafast gradient-echo sequence with incremented flip angle series and k-space segmentation was used. The image quality grade, length, and proximal diameter of each visualized coronary artery were measured. The highest quality images in systole and diastole were compared. Coronary MR angiography provided high quality images in systole and diastole in 14 of 16 coronary vessels (87.5%). In 8 of 14 vessels (57%), there was no visible coronary MR angiogram image degradation when comparing peak systolic with mid-diastolic images. In 4 of 14 vessels (29%), there was mild MR image degradation. There was significant MR image degradation in only one case (7%). And in one case (7%), there was mild image improvement during systole. The width and length of the visualized coronary vessels did not change significantly from diastole to systole. Existing two-dimensional breath-hold coronary MR angiography provides MR images during peak systole and mid-diastole with little or no perceptible difference in quality.

Adult↗