PubMed Health⌕ Search

Biomedical subjects

Mark W Wilson

Publications and source records attributed to Mark W Wilson.

8 recordsLinked to original sources
PubMed2003

Reversal of flow in the ovarian artery during uterine artery embolization.

Uterine artery embolization (UAE) is gaining increasing recognition as an effective treatment alternative to hysterectomy in select patients. As interventional radiologists gain more experience in the treatment of fibroids, new interest is being directed toward arterial communications between the uterine arteries and ovarian arteries. This case report focuses on the potentially serious complication of flow reversal up the ovarian artery into the aorta during UAE.

Adult↗
PubMed2002

Real-time MR properties of particulate embolic agents tested in a dynamic flow model.

PURPOSE: Interventional magnetic resonance (MR)-guided transcatheter embolization could potentially limit radiation exposure and improve visualization of target organs. The feasibility of monitoring injection and distribution of embolic agents was assessed in a dynamic flow model with real-time MR imaging. MATERIALS AND METHODS: MR-compatible flow models were constructed with use of clear plastic chambers containing 170-microm polyethylene tubular filters. Gadolinium (Gd)-impregnated polyvinyl alcohol (PVA) particles (355-500 and 500-710 microm in size) and Gd-impregnated microspheres (Embospheres, 300-500 and 500-700 microm in size) were injected into the flow circuit under real-time dynamic T1-weighted fast field echo guidance at four images per second. A dynamic steady-state free precession sequence at four images per second was used to monitor the injection of unmodified Embo-Gold 700-900- microm particles. High-resolution scans were obtained before and after each particle injection. RESULTS: MR signal enhancement on the dynamic T1-weighted fast field echo sequence was visible during the injection of Gd-impregnated microspheres. Gd-impregnated PVA particles were not detected by this sequence. After injection, microsphere and PVA localization to the filter chambers was confirmed by the high-resolution scans. On the high-resolution sequences, relative MR signal enhancement of the microspheres was higher than that of the PVA particles. The Embo-Gold particles were minimally detectable on the dynamic sequence and undetectable by the high-resolution scan. After particle injection, direct inspection of the filter chamber showed trapping of all particle types and sizes. CONCLUSION: Real-time MR tracking of Gd-impregnated embolic agents is possible in vitro.

Embolization, Therapeutic↗
PubMed2002

MR portal venography: preliminary results of fast acquisition without contrast material or breath holding.

RATIONALE AND OBJECTIVES: The authors performed this study to evaluate the feasibility of using the steady-state free precession (SSFP) sequence to perform magnetic resonance (MR) venography of the portal venous system without the use of contrast material or breath holding. MATERIALS AND METHODS: Eleven patients underwent MR venography with the SSFP technique. Coronal three-dimensional images were obtained with respiratory triggering. Contrast material and respiratory suspension were not used. All patients had recently undergone at least one other imaging study (conventional angiography, transhepatic portal venography, ultrasound, or contrast-enhanced computed tomography), and these findings were correlated with those from MR venography. The structures evaluated were the main portal vein, right portal vein, left portal vein, superior mesenteric vein, and splenic vein. RESULTS: MR venography with SSFP accurately depicted the status of these veins in all cases except one. In this patient, MR venography depicted portal vein thrombus but could not indicate that it was tumor thrombus. CONCLUSION: MR venography with SSFP accurately depicted the portal venous system in 10 of 11 patients without the use of respiratory suspension or contrast material.

Adult↗
PubMed2002

Integrated fellowship in vascular surgery and intervention radiology: a new paradigm in vascular training.

OBJECTIVE: To evaluate an integrated fellowship in vascular surgery and interventional radiology initiated to train vascular surgeons in endovascular techniques and to train radiology fellows in clinical aspects of vascular diseases. SUMMARY BACKGROUND DATA: The rapid evolution of endovascular techniques for the treatment of vascular diseases requires that vascular surgeons develop proficiency in these techniques and that interventional radiologists develop proficiency in the clinical evaluation and management of patients who are best treated with endovascular techniques. In response to this need the authors initiated an integrated fellowship in vascular surgery and interventional radiology and now report their interim results. METHODS: Since 1999 vascular fellows and radiology fellows performed an identical year-long fellowship in interventional radiology. During the fellowship, vascular surgery and radiology fellows perform both vascular and nonvascular interventional procedures. Both vascular surgery and radiology-based fellows spend one quarter of the year on the vascular service performing endovascular aortic aneurysm repairs and acquiring clinical experience in the vascular surgery inpatient and outpatient services. Vascular surgery fellows then complete an additional year-long fellowship in vascular surgery. To evaluate the type and number of interventional radiology procedures, the authors analyzed records of cases performed by all interventional radiology and vascular surgery fellows from a prospectively maintained database. The attitudes of vascular surgery and interventional radiology faculty and fellows toward the integrated fellowship were surveyed using a formal questionnaire. RESULTS: During the fellowship each fellow performed an average of 1,201 procedures, including 808 vascular procedures (236 diagnostic angiograms, 70 arterial interventions, 59 diagnostic venograms, 475 venous interventions, and 43 hemodialysis graft interventions) and 393 nonvascular procedures. On average fellows performed 20 endovascular aortic aneurysm repairs per year. There was no significant difference between the vascular surgery and radiology fellows in either the spectrum or number of cases performed. Eighty-eight percent (23/26) of the questionnaires were completed and returned. Both interventional radiologists and vascular surgeons strongly supported the integrated fellowship model and favored continuation of the integrated program. Vascular surgery and interventional radiology faculty members wanted additional training in clinical vascular surgery for the radiology-based fellows. With the exception of the radiology fellows there was uniform agreement that vascular surgery fellows benefit from training in nonvascular aspects of interventional radiology. CONCLUSIONS: Integration of vascular surgery and interventional radiology fellowships is feasible and is mutually beneficial to both disciplines. Furthermore, the integrated fellowship provides exceptional training for vascular surgery and interventional radiology fellows in all catheter-based techniques that far exceeds the minimum requirements for credentialing suggested by various professional societies. There is a clear need for cooperation and active involvement on the parts of the American Board of Radiology and the American Board of Surgery and its Vascular Board to create hybrid training programs that meet mutually agreed-on criteria that document sufficient acquisition of both the cognitive and technical skills required to manage patients undergoing endovascular procedures safely and effectively.

Attitude of Health Personnel↗
PubMed2002

Evaluation of active bleeding into hematomas by technetium-99m red blood cell scintigraphy before angiography.

PURPOSE: To evaluate the utility of technetium-99m red blood cell (Tc-99m RBC) scintigraphy in the diagnosis of active hemorrhage into large intra-abdominal hematomas before arteriography. METHODS: This retrospective case series describes four patients (1 man and 3 women) with large abdominal wall and retroperitoneal hematomas confirmed by computed tomography who underwent Tc-99m RBC scintigraphy before angiography. Arterial transcatheter embolization was performed if active hemorrhage was found. RESULTS: Three of the patients had positive findings on Tc-99m RBC scans, which showed spreading of the labeled erythrocytes into the hematoma space. Positive scintigraphy was diagnostic for active hemorrhage and helped localize the bleeding sites. Angiography confirmed the diagnosis in all patients with positive scintigraphy and ruled out active bleeding in the patient with a negative Tc-99m-labeled RBC scan. CONCLUSION: Tc-99m RBC scintigraphy appears to be sensitive and accurate in detecting active hemorrhage into intra-abdominal hematomas.

Abdominal Wall↗
PubMedDate not supplied

Benign tracheobronchial stenoses: changes in short-term and long-term pulmonary function testing after expandable metallic stent placement.

PURPOSE: To determine the short- and long-term improvement in airflow dynamics in patients undergoing tracheobronchial stent placement for benign airway stenoses. METHODS: Twenty-two patients underwent 34 tracheal and/or bronchial stent placement procedures for benign airway stenoses and had the results of pulmonary function tests available. Stent placement indications included bronchomalacia after lung transplantation (n = 11), postintubation stenoses (n = 6), relapsing polychondritis (n = 2), and 1 each of tracheomalacia, tracheal compression, and histoplasmosis. Six patients underwent more than one stent placement procedure (range: 2-7 procedures). The mean forced expiratory volume in one second (FEV(1) ), forced expiratory flow rate in the midportion of the forced vital capacity curve (FEF(25-75) ), forced vital capacity, and peak flow (PF) rate obtained before stent placement were compared with those immediately after stent placement and with those measurements most remote from stent placement using the paired two-tailed test. RESULTS: All patients reported improved respiratory function immediately after stent placement. The mean FEV(1), FEF(25-75), and PF rate improved significantly (p < 0.001, p = 0.002, and p = 0.009, respectively) after stent placement. On long-term follow-up averaging 15 months after stent placement, these parameters declined despite patients' subjective sense of improvement. Segregating the population into transplant and nontransplant airway stenosis etiologies, however, FEF(25-75) and PF rate remained significantly improved (p = 0.045, p = 0.027, respectively), over the long term for the latter. FEV increased after subsequent stent placements for patients receiving multiple stents. CONCLUSION: Stent placement for benign tracheobronchial stenoses provides significant immediate improvement in airflow dynamics. Long-term improvement in airflow obstruction may be expected, and additional stent placements may further improve pulmonary function.

Adult↗