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Biomedical subjects

C J Whigham

Publications and source records attributed to C J Whigham.

14 recordsLinked to original sources
PubMed2000

Diagnostic radiology residents in the classes of 1999 and 2000: fellowship and employment.

OBJECTIVE: Most diagnostic radiology residents undergo fellowship training. Applications for fellowship positions are submitted during the third year of residency. We compared the number of residents undertaking fellowship, accepting jobs, and rescinding accepted fellowship positions to accept jobs. MATERIALS AND METHODS: During the 47th Association of University Radiologists meeting, participants from the American Association of Academic Chief Residents in Radiology completed a questionnaire regarding the intentions of third- and fourth-year residents in their programs. RESULTS: Seventy programs, representing 402 fourth-year and 395 third-year residents, responded. Of fourth-year residents, 322 (80.1%) accepted fellowships and 41 (10.2%) accepted jobs. Of third-year residents, 335 (84.8%) accepted fellowships. Eighty-eight (27.3%) fourth-year residents and 95 third-year residents (28.4%) accepted interventional radiology fellowships, and 104 (32.3%) fourth-year residents and 96 (28.7%) third-year residents accepted body imaging fellowships. Most residents who accepted fellowships did so in the same city in which they completed their residency training. Of fourth-year residents who accepted fellowship positions the year before, 14 (4.3%) withdrew their acceptance to pursue employment. CONCLUSION: Most residents opt for fellowship training in interventional radiology or body imaging. We postulate that the practice of accepting fellowships during the third year of residency may contribute to the percentage of residents who rescind fellowship acceptance to pursue employment. We suggest that consideration be given to changing this practice.

Data Collection↗
PubMed1999

Infectious complications of 393 peripherally implantable venous access devices in HIV-positive and HIV-negative patients.

PURPOSE: To compare and investigate the rate of infection in patients with and without human immunodeficiency virus (HIV) who have implantable venous access devices placed by interventional radiologists. MATERIALS AND METHODS: Three hundred ninety-one patients undergoing radiologically guided placement of peripheral arm ports were grouped according to their HIV serologic status. Findings were prospectively reviewed in 393 peripherally placed arm ports that were implanted in the basilic, cephalic, or brachial vein under fluoroscopic or sonographic guidance over a 4-year span. Infectious complications were categorized according to severity (local or systemic) and time (periprocedural or late). RESULTS: Three hundred ninety-three ports have been indwelling for a total of 97,256 patient days (range, 1-694; mean duration, 247 days). Among the 30 catheter placements in 29 HIV-positive patients with a total exposure time of 7,242 days, five (one local and four systemic) infections occurred, resulting in a 16.6% overall infection rate, yielding 0.069 infections per 100 catheter days at risk (95% confidence interval [CI], 0.032-0.127). In the remaining 362 HIV-negative patients, 27 (14 local and 13 systemic) infectious complications (7.4%) occurred, translating into 0.030 infections per 100 catheter days (95% CI, 0.021-0.042). The odds ratio of getting an infection from the implantable arm ports in the HIV-positive group was 2.5 times higher than that of the HIV-negative group. The relative risk was similar and was calculated to be 2.3. The P value was .084 (P < .05 required to be considered significant). CONCLUSIONS: These results suggest a significant difference in the infectious complication rate encountered in HIV-positive patients compared with the general population. However, the HIV-positive peripheral arm port infection rate compares favorably with the surgically placed catheters and ports. Many more arm ports in HIV-positive patients must be evaluated for the data to achieve an acceptable level of statistical significance.

Adolescent↗
PubMed1999

Incidence and management of catheter occlusion in implantable arm ports: results in 391 patients.

PURPOSE: To evaluate the incidence and management of catheter occlusion in implantable arm ports. MATERIALS AND METHODS: Findings were prospectively examined in 391 patients in whom 393 arm ports were placed. The indications for port placement included chemotherapy (n = 347), antibiotic administration (n = 35), combination chemotherapy/antibiotic use (n = 7), transfusion (n = 3), and phlebotomy (n = 1). Of the total catheters, 323 (82.2%) underwent tip modification prior to placement. Malfunctioning catheters were usually treated with urokinase instillation. RESULTS: Three hundred ninety-three devices were implanted with 247 mean days of catheter use (total, 97,256 days; range, 1-694 days). The overall incidence of catheter occlusion was 0.14 per 100 catheter days. A single catheter occlusion occurred in 90 (22.9%) catheters, with a mean of 90.1 days before the event. A second occlusion occurred in 36 (9.2%) of the above catheters, with a mean of 60.1 catheter days before the second event. Eighty-five (24.0%) of the 347 cancer patients had at least one occlusive event, yielding a complication rate of 0.098 per 100 catheter days at risk (95% confidence interval [CI]; 0.079-0.114). Of the 35 patients receiving antibiotics, three (8.6%) had at least one occlusive event. This represented a complication rate of 0.032 per 100 catheter days at risk (95% CI; 0.010-0.061). Seventeen (24.3%) of the nonmodified catheters developed an occlusion versus 72 (22.3%) of the modified (P > .05; Fisher exact test). Of the catheters with a first occlusive event, 75 (98.7%) were treated successfully with urokinase instillation. Four (1.0%) patients developed symptomatic subclavian vein thrombosis. No bleeding complications occurred. CONCLUSION: Catheter occlusion is a common complication of long-term arm port placement, with a significantly higher incidence in the cancer patients in our series (P <. 05, Fisher exact test). Catheter tip modification, however, does not considerably affect the incidence of occlusion. Low-dose urokinase therapy is a safe and efficacious treatment of catheter occlusion, obviating the need for catheter removal.

Adolescent↗
PubMed1992

Placement of dual bird's nest filters in an unusual case of duplicated inferior vena cava.

The authors describe an unusual variant of inferior vena cava duplication, with azygos continuation of the right vena cava and hemiazygos continuation of the left vena cava, discovered at cavography in a patient with pulmonary embolism. Following unsuccessful attempts to advance titanium Greenfield filters through tortuous iliac veins, bilateral Bird's Nest filters were placed successfully.

Aged↗
PubMed1990

Conservative management of aortic lacerations due to blunt trauma.

Three patients with angiographically documented thoracic aortic lacerations were managed conservatively over 8 years due to the nonthreatening appearance of the injuries in two and the presence of an associated major closed head injury in a third. The lesion(s) resolved in one, diminished in another, and remained unchanged in the third. At least ten other cases managed similarly are recorded in the literature. In certain selected circumstances this approach may represent a viable alternative to the current standard of immediate surgical correction of aortic injuries.

Adult↗
PubMedDate not supplied

Diverticula of Kommerell and aberrant subclavian arteries complicated by aneurysms.

This is a retrospective evaluation of the incidence of aberrant subclavian arteries (ASAs) and diverticula of Kommerell, as well as the occurrence and significance of associated aneurysms. Thoracic aortograms obtained during a 12.5-year period were reviewed, seeking the presence of aberrant right and left subclavian arteries (ARSAs/ALSAs), diverticula of Kommerell, and the incidence of associated aortic aneurysms. Several cases were evaluated with computed tomography concomitantly. Results were correlated with a literature review. Twenty-two ASAs were identified. Nineteen were on the right (ARSAs) and three were on the left (ALSAs). A diverticulum of Kommerell (DOK) was also present on the right in seven and on the left in three. Five of these patients had complicating aneurysms. Four of these were associated with ARSAs and their diverticula. Two were atherosclerotic; one was a limited dissection and one of uncertain etiology was ruptured. One additional aneurysm (atherosclerotic) involved an ALSA/DOK. The patient with the ruptured aneurysm died in surgery; three were managed conservatively because of concomitant disease; and one is being followed because of the small size (2.5 cm) of the aneurysm. ARSAs are relatively uncommon and ALSAs are rare. Both ARSA and ALSA are frequently associated with a DOK. Aneurysms rarely involve ASAs (with or without a DOK), but they are associated with a high mortality rate if they are not discovered before rupture. Early diagnosis plus surgical and/or endovascular management can be lifesaving.

Adult↗
PubMedDate not supplied

"Lumps" and "bumps" that mimic acute aortic and brachiocephalic vessel injury.

Laceration of the thoracic aorta or brachiocephalic vessels due to blunt trauma is relatively common. In such cases, prompt and accurate diagnosis followed by timely surgery is essential. These injuries typically occur at the aortic isthmus and can usually be readily identified at aortography, which remains the standard of reference for diagnosis. However, numerous anatomic variants that manifest as "lumps" or "bumps" on aortograms can mimic true vascular injury, thereby leading to false-positive or false-negative diagnosis. These variants include aortic spindle, classic or atypical ductal diverticula, and infundibula of the brachiocephalic arteries and adjacent branches or of the right third intercostal artery. Ductus diverticula typically occur at the isthmus and have smooth, uninterrupted margins with gently sloping shoulders. Infundibula are also smoothly marginated but can occur in a variety of locations and generally taper into one or more vessels at their apex. Knowledge of the imaging appearances of these anatomic variants is necessary for correct interpretation of aortograms of the aorta and brachiocephalic vessels in blunt trauma patients.

Adult↗
PubMedDate not supplied

Subtle or atypical injuries of the thoracic aorta and brachiocephalic vessels in blunt thoracic trauma.

Aortic or brachiocephalic vessel injuries secondary to blunt thoracic trauma are relatively common and can occur throughout the length of the thoracic aorta or in various locations in the brachiocephalic vessels. Aortography remains the standard of reference for the diagnosis of these injuries despite recent technologic advances in other imaging modalities. The classic aortographic finding in aortic or brachiocephalic vessel injury consists of a large false aneurysm, typically protruding from the medial aspect of the aortic isthmus. However, intrathoracic aortic or brachiocephalic vessel injury can and does occur at any intrathoracic location and may exhibit a wide variety of radiographic appearances, thereby presenting a diagnostic challenge even for experienced trauma angiographers. Large false aneurysms may appear oval or rounded, tubular, or asymmetrically globular and may manifest in unusual locations such as the ascending aorta. Although smaller, irregularly shaped false aneurysms at atypical locations may be obscure or mimic ductus diverticula, their irregular, sharp margins allow them to be distinguished as injuries. The subtlety of aortic or brachiocephalic vessel injuries necessitates a high degree of suspicion along with meticulous imaging technique in all cases and the use of additional projections in equivocal cases for definitive diagnosis.

Adult↗
PubMedDate not supplied

Vascular gene therapy.

Gene therapy is an exciting frontier in medicine today. Radiologists will be involved in tracking the effects of these new therapies through imaging. Vascular and interventional radiology techniques also are ideally suited for minimally invasive, readily monitored gene delivery. Gene therapy is accomplished through gene augmentation or gene blocking. The latter is accomplished through antisense oligonucleotides or transcription factor decoys. Vectors are agents that facilitate gene delivery and expression and can be viral or nonviral. The vascular wall is an ideal target for gene therapy because of its central role in many biologic processes and its ready accessibility. Recombinant genes can be delivered ex vivo and in vivo, with the latter approaches involving open surgical, percutaneous injection, and endovascular catheter-based methods. Perforated, hydrogel-coated, and double balloon catheters have been used with varying success. Optimal catheter systems for gene transfer will enable delivery of the vector to the precise anatomic location with transfection limited to the cells of interest and will minimize shedding of the vector to distal sites, systemic effects of the therapeutic agent, and morbidity from the delivery method. Radiologists must become familiar with the basic rationale, strategies, and mechanisms of gene therapy and involved in its clinical trials to ensure an active role in this field.

Coronary Disease↗