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Biomedical subjects

W Dennis Foley

Publications and source records attributed to W Dennis Foley.

13 recordsLinked to original sources
PubMed2005

Liver: surgical planning.

Hepatic surgery for primary malignant disease, either hepatocellular or cholangiocarcinoma, is performed with curative intent, whereas surgery for metastatic disease, either functional endocrine metastases or isolated colorectal metastases, is essentially palliative, aiming to increase duration of survival and quality of life. Patient selection is dependent upon clinical and imaging criteria. The aim of imaging is to define site, size, and multiplicity of tumor in relation to segmental anatomy, vessels and ducts and evaluate for extrahepatic metastatic disease. A multimodality approach employing sonography, CT, MRI and MRCP, and isotope imaging is used as appropriate in each circumstance. The ultimate goal of imaging is to provide a surgeon with anatomic information that will result in a resection with negative free margin or a decision to use resection, ablation, or chemoembolization techniques alone or in concert for best potential outcomes.

Carcinoma, Hepatocellular↗
PubMed2005

Feasibility and validation of registration of three-dimensional left atrial models derived from computed tomography with a noncontact cardiac mapping system.

OBJECTIVES: The purpose of this study was to determine the feasibility and assess the validity of registering three-dimensional (3D) models from computed tomographic (CT) images using a cardiac mapping system. BACKGROUND: Registration of 3D anatomic models with an interventional system could help identify and navigate mapping and ablation catheters over a complex structure such as the left atrium (LA). METHODS: ECG-gated, contrast-enhanced cardiac CT imaging was performed in 14 patients with atrial fibrillation. Segmentation was used to create 3D models of the LA. The 3D models were registered with the mapping system using a series of fiducial points. Registration was accomplished retrospectively in the first 10 patients, and catheter navigation was visualized from recorded data. In the final four patients, registration was accomplished in real time during electrophysiologic study. The mapping catheter position, as it was navigated inside the LA, was applied to the registered model in real time. For the validation study, temporary pacing leads were implanted in the LA of 10 dogs. Following this, CT scanning, segmentation, LA model importation, and registration was described previously. After registration, a mapping catheter was positioned at the site of each buried lead according to the registered model with no fluoroscopic guidance. A radiofrequency lesion was created at this location, and the dog was sacrificed, the heart removed and stained, and the distance between the buried lead and the lesion measured. RESULTS: During the feasibility study, the location of the catheter in the registered model correlated with fluoroscopy, angiography, and intracardiac electrograms. LA endocardial potentials during sinus rhythm and any premature atrial contractions also were successfully delineated over the registered models. In the validation study, the mean target registration error was 2.0 +/- 3.6 mm. CONCLUSIONS: Registration of CT-derived 3D models of the LA using a cardiac mapping system is feasible and accurate.

Animals↗
PubMed2005

CT urography of urinary diversions with enhanced CT digital radiography: preliminary experience.

OBJECTIVE: The purpose of this study was to determine if 3D-rendered CT urography (CTU) depicts both normal and abnormal findings in patients with urinary diversions and if the addition of contrast-enhanced CT digital radiography (CTDR) improves opacification of the urinary collecting system. MATERIALS AND METHODS: Thirty CTU and contrast-enhanced CTDR examinations were performed in 24 patients who underwent cystectomy for bladder cancer. Indications for evaluation included hematuria, tumor surveillance, or suspected diversion malfunction. All examinations were evaluated without knowledge of the stage or grade of a patient's tumor and were compared with the clinical records. Opacification of the urinary collecting system was evaluated with 3D CTU alone, contrast-enhanced CTDR alone, and combined CTU and CTDR. RESULTS: Nine abnormalities were identified including distal ureteral strictures (n = 4), vascular compression of the mid left ureter (n = 1), scarring of the mid right pole infundibulum (n = 1), bilateral hydronephrosis and hydroureter (n = 1), urinary reservoir calculus (n = 1), and tumor recurrence invading the afferent limb of the neobladder (n = 1). Eight of the nine detected abnormalities were surgically or pathologically confirmed. All abnormalities were identified on all three imaging techniques but were best seen on 3D CTU and enhanced CTDR images. Incomplete opacification of the urinary collecting system occurred in 17 patients with CTU alone, 12 patients with contrast-enhanced CTDR alone, and nine patients with combined CTU and contrast-enhanced CTDR. Compared with CTU alone, the combined technique of 3D CTU and contrast-enhanced CTDR improved opacification by a statistically significant difference (p = 0.037). CONCLUSION: CTU with 3D rendering can accurately depict both normal and abnormal postoperative findings in patients with urinary diversions. Adding enhanced CTDR can improve visualization of the urinary collecting system.

Adult↗
PubMed2004

Abdominal MDCT: liver, pancreas, and biliary tract.

Multidetector row computed tomography (MDCT) enables rapid thin-section acquisition of regional body anatomy. MDCT is adapted to hepatic and pancreatic imaging to produce, in appropriate clinical circumstances, a multipass multiplanar study obtained during defined circulatory phases to best outline vasculature and detect and characterize focal parenchymal lesions. In this chapter, a rational approach to hepatic and pancreatic MDCT acquisition is outlined with emphasis on circulatory phases and contrast material pharmacokinetics as well as biological characteristics of focal parenchymal lesions.

Biliary Tract↗
PubMed2003

Renal MDCT.

Multidetector CT has expanded the utility of CT by improving longitudinal resolution and acquisition speed. Applications include diagnosis of renal vascular and parenchymal injuries, renal tumor diagnosis and staging, the emerging field of CT urography and CT angiography. This summary review illustrates MDCT approaches to the evaluation of trauma, suspected tumor and imaging of the urinary tract and discusses other applications in renal inflammatory disease, urolithiasis and renal anomalies.

Contrast Media↗
PubMed2002

Scrotal ultrasonography with emphasis on the extratesticular space: anatomy, embryology, and pathology.

Sonography is the imaging modality of choice in detecting and characterizing pathologic conditions affecting the extratesticular space. Although most abnormalities are benign, many may simulate or represent malignant processes. Accurate diagnosis is therefore essential and must be based not only on the sonographic findings but also on accurate clinical history and physical examination findings. This article reviews the anatomy, embryologic development, and pathologic conditions affecting the extratesticular space.

Journal Article↗
PubMedDate not supplied

Quality assurance methods for the first Radiation Therapy Oncology Group permanent prostate implant protocol.

PURPOSE: To report the quality assurance methodology used by the Radiation Therapy Oncology Group in the first cooperative group, multi-institution Phase II trial of transrectal ultrasound guided permanent radioactive implantation of the prostate for definitive treatment of localized adenocarcinoma of the prostate. METHODS AND MATERIALS: Participating institutions were credentialed to participate in this protocol, Radiation Therapy Oncology Group 98-05. International Commission on Radiation Units and Measurements (ICRU) Report 58 was used as the basis for definition of terms. The AAPM's dosimetric prerequisites for low energy interstitial brachytherapy sources were adopted. A nondigital approach to central review was used. The implant dosimetry was recalculated based upon centrally reviewed target volumes by both a radiation oncologist and a diagnostic radiologist. RESULTS: There are differences in the definition of the postimplant prostate between the participating institution, the central review radiation oncologist, and the central review diagnostic radiologist. Thus, there are differences in dose/volume parameters. Six of the 95 patients reviewed did not meet the per protocol criteria based upon information supplied by the participating institution. This increased to 18 cases when using the postimplant target volume defined by the central oncologist and to 23 cases when defined by the radiologist. CONCLUSIONS: This work indicated that there is a need for a central review process of dose-volume analysis within the cooperative group setting. It is indicated that a digital approach to centralized review, which has now been developed, would result in a higher quality and easier review.

Adenocarcinoma↗
PubMedDate not supplied

Gadolinium-enhanced multidetector CT angiography of the thoracoabdominal aorta.

A 93-year-old patient with a cardiac pacemaker and biochemical renal failure presented with back pain suspicious for dissection. We performed gadolinium-enhanced thoracoabdominal multidetector CT angiography using eight-channel multidetector CT. Uniform aortic enhancement of 140 HU was sufficient to exclude aortic dissection and defined an unruptured infrarenal abdominal aortic aneurysm.

Aged↗
PubMedDate not supplied

Computed tomography angiography: principles and clinical applications.

Clinical applications of computed tomography (CT) angiography have increased with the improved technology of multidetector CT systems. Adequate contrast enhancement and the timing of image acquisition are key elements in producing technically adequate CT angiograms. This review article provides guidelines and protocols for four-, eight- and 16-channel multidetector systems in studies of the thoracoabdominal aorta, aortoiliac, and abdominal visceral vasculature, abdominal and extremity run-off studies, and carotid/cerebral CT angiography.

Angiography↗
PubMedDate not supplied

Multidetector computed tomography and blunt thoracoabdominal trauma.

Computed tomography has had an increasing role in the evaluation of patients after blunt trauma. Important findings in thoracic trauma include acute traumatic aortic injury, pneumothorax, hemothorax, pulmonary contusions and lacerations, mediastinal hematoma, and diaphragmatic rupture. The solid abdominal viscera may lacerate; infarct; or suffer vascular, ductal, or pyelocalyceal disruption. The bladder and intestines may rupture. In abdominal pelvic trauma, the direction of applied force often results in an identifiable constellation of injuries. This article reviews how multidetector computed tomography (MDCT) is used in the trauma patient. Technical advances of increased cephalocaudad coverage speed and improved z-axis resolution intrinsic to MDCT, together with effective contrast utilization, make MDCT invaluable in the setting of trauma.

Abdominal Injuries↗
PubMedDate not supplied

Special focus session: multidetector CT: abdominal visceral imaging.

Multidetector computed tomography (CT) has diffused rapidly into clinical imaging practice in a short time. Major improvements in relation to single-detector CT are faster image acquisition and improved z-axis resolution. Abdominal visceral imaging with multidetector CT uses both the vascular and parenchymal phases of contrast material enhancement to provide a combined angiographic and multipass organ-directed study. All examinations are performed with standard contrast material loads.

Abdominal Injuries↗
PubMedDate not supplied

Image Interpretation Session: Sunday, November 27, 2005.

The Sunday afternoon Image Interpretation Session has been a high point of the annual meeting of the Radiological Society of North America for over 65 years. A panel of five experts has been selected, representing the very best from the fields of neurologic, abdominal, thoracic, pediatric, and musculoskeletal radiology. Each panelist will dazzle us with an insightful analysis of two difficult cases in their area of expertise. The panelists are to be lauded for their bravery in subjecting their diagnostic acumen to the scrutiny of the thousands of radiologists in the audience. The cases, representing a diverse spectrum of diseases and disease manifestations, were selected from recent clinical imaging studies performed at the Stanford University Medical Center or the Lucille Salter Packard Children's Hospital. This session celebrates the skills of diagnostic radiologists worldwide, who are called on daily to amalgamate disparate clinical information with complex imaging data into focused differential diagnoses and effective treatment planning. We hope that these cases will serve to illustrate the central role that expert image interpretation plays in the care of patients. We welcome our audience of RSNA attendees, readers of RadioGraphics, and cyberspace denizens to join with our experts in solving these medical puzzles and to enjoy the excitement of unraveling the unknown.

Adolescent↗