Priscilla A. Winchester

Contrast-enhanced peripheral MR angiography from the abdominal aorta to the pedal arteries: combined dynamic two-dimensional and bolus-chase three-dimensional acquisitions.

Wang Y, Winchester PA, Khilnani NM, et al. Contrast-enhanced peripheral MR angiography from the abdominal aorta to the pedal arteries: Combined dynamic two-dimensional and bolus-chase three-dimensional acquisitions. Invest Radiol 2001;36:170–177. rationale and objectives. To obtain reliable contrast-enhanced peripheral MR angiography for imaging peripheral vascular disease from the abdominal aorta to the pedal arteries. methods.A protocol consisting of contrast-enhanced, dynamic two-dimensional (2D) acquisition at the feet and calf and bolus-chase three-dimensional (3D) acquisition from the abdominal aorta to the calf was developed and applied in patients with peripheral vascular disease. The performance of this integrated protocol was assessed in 89 consecutive patients. results.The bolus-chase 3D acquisition was of diagnostic quality in 100% of the acquisitions in the abdomen, 96% in the thigh, and 43% in the calf. The poor quality of the calf acquisitions was due to insufficient spatial resolution, poor arterial signal, and venous contamination. Diagnostic-quality images were obtained in 100% of the dynamic 2D acquisitions of the calf and 98% of the feet. conclusions.The combined dynamic 2D and bolus-chase 3D contrast-enhanced MR angiography technique provides diagnostic images of the entire lower extremity.

Bolus arterial-venous transit in the lower extremity and venous contamination in bolus chase three-dimensional magnetic resonance angiography

Wang Y, Chen CZ, Chabra SG, et al. Bolus arterial-venous transit in the lower extremity and venous contamination in bolus chase three-dimensional magnetic resonance angiography. Invest Radiol 2002;37:458–463. rationale and objectives. To investigate the phenomena and causes for undesired venous signal in the distal station of bolus chase 3D MRA. methods. Consecutive patients (in 8 months) undergoing peripheral MRA consisting of 2D projection MRA of the tibial trifurcation and 3D bolus chase MRA were retrospectively evaluated. Venous contamination in mid-calf in bolus chase 3D MRA was correlated to the arterial phase duration, the time between the contrast bolus arrival and venous return measured on time resolved 2D images. Statistical analyses were performed to identify the clinical parameters indicative of venous contamination. results. The arterial phase durations at the mid-calf were 49 ± 8 seconds on 101 legs without venous signal in the bolus chase 3D MRA, 35 ± 9 seconds on 13 legs with moderate venous signal, and 20 ± 4 seconds on 40 legs with substantial venous signal; the differences were significant among different venous signal levels (P < 0.001 for all pairs). Legs with cellulitis had shorter arterial phase and more venous contamination than legs without cellulitis (P < 0.05). Patients with myocardial infarction had longer arterial phase and less venous contamination than patients without myocardial infarction (P < 0.01). conclusion. Venous signal in the distal calf station of bolus chase 3D peripheral MRA is caused by fast arterial-venous transit. It is worse in legs with cellulitis and less in patients with a history of myocardial infarction.

Renal Artery Stenosis: Imaging Options, Pitfalls, and Concerns

Renal artery stenosis can be diagnosed with multiple imaging modalities, each one having different risk vs accuracy tradeoffs. Catheter angiography with pressure gradient measurements is the definitive gold standard but also the most invasive and thus reserved primarily for imaging at the time of renal revascularization. Ultrasonography is the safest and least expensive but also the least accurate and most operator-dependent. Contrast-enhanced computed tomographic angiography and magnetic resonance angiography are intermediate (between ultrasound and catheter angiography) with respect to accuracy and expense. Exciting new advances in magnetic resonance that include new contrast agents, which eliminate nephrogenic systemic fibrosis risk, and techniques to characterize the hemodynamic significance of renal artery stenoses are now becoming available. In addition, magnetic resonance angiography without any contrast has become more accurate and rivals contrast-enhanced techniques in some patients. This review explores these techniques for renal artery stenosis imaging.

Comparison of Two-dimensional MR Digital Subtraction Angiography of the Lower Extremity with X-Ray Angiography☆

PURPOSE To perform a preliminary evaluation of the diagnostic accuracy of contrast-enhanced, two-dimensional (2D) magnetic resonance (MR) digital subtraction angiography (DSA) of the lower extremity by comparison with x-ray angiography (XRA). MATERIALS AND METHODS Forty lower extremities in 22 patients were imaged at multiple levels with both XRA and 2D MR DSA. Images were retrospectively analyzed by three radiologists in a randomized blinded manner. Seventeen vascular segments were graded as an insignificant lesion, a significant lesion, or as an occlusion. With the use of segments well depicted with XRA as the gold standard, the sensitivity, specificity, and accuracy of 2D MR DSA, as compared with XRA, were evaluated. The McNemar-Stuart-Maxwell test was performed to determine the significance of any differences found. RESULTS Three hundred eighty-three arterial segments were evaluated with both techniques. Three hundred one segments were well depicted with XRA. There was no significant difference between 2D MR DSA and XRA for assessing the degree of occlusive disease in these 301 segments (.25 < P < .5). The sensitivity, specificity, and diagnostic accuracy of 2D MR DSA were found to be 90%, 98%, and 93%, respectively. CONCLUSION Two-dimensional MR DSA is an accurate method for assessing arterial lesions in the lower extremity.

Perforator flap magnetic resonance angiography for reconstructive breast surgery: A review of 25 deep inferior epigastric and gluteal perforator artery flap patients

To evaluate the accuracy of magnetic resonance angiography (MRA) for preoperative mapping of rectus and gluteal muscle perforating arteries prior to autologous flap breast reconstruction.

Recessed elliptical-centric view-ordering for contrast-enhanced 3D MR angiography of the carotid arteries

Fast arterial‐venous transit in the carotid arteries requires accurate, reliable timing of the acquisition to the bolus transit to maximize arterial signal and minimize venous artifacts. The rising edge of the bolus is not utilized in conventional elliptical‐centric view‐ordering because the critical k‐space center must be acquired with full arterial enhancement. In this study, a recessed elliptical‐centric view‐ordering scheme is introduced in which the k‐space center is acquired a few seconds following scan initiation. The recessed view‐ordering is shown to be more robust to timing errors than the conventional scheme in a study of 37 patients. Magn Reson Med 48:419–424, 2002.

Soft tissue enhancement on time-resolved peripheral magnetic resonance angiography

To evaluate the incidence and locations of soft tissue enhancement on time‐resolved two‐dimensional projection magnetic resonance angiography (MRA) of the calf and foot.

Three‐dimensional MR angiography in imaging platinum alloy stents

To evaluate visualization inside platinum stents with three‐dimensional contrast‐enhanced magnetic resonance angiography (CE‐MRA).

Axillary Artery Aneurysm With Distal Embolization in a Major League Baseball Pitcher

Aneurysms of the axillary artery and occlusions of the humeral circumflex arteries in elite baseball pitchers are not rarities. Although this entity is well described in the vascular surgery literature, there are few reports in the orthopaedic literature. This is important because most team physicians are orthopaedic surgeons, and the team physician will often have the first chance to make a diagnosis and initiate early treatment. Early detection and treatment of axillary artery aneurysms may prevent catastrophic injury and may allow the professional baseball player to continue pitching at an elite level and prolong his career. The presenting symptoms of axillary artery aneurysms rarely originate from the shoulder region. Instead, the presenting symptoms are often attributable to ischemia of the distal extremity caused by emboli that originated from the more proximal aneurysm. Hand and finger numbness with the sensation of “coldness” in the fingertips while gripping and throwing a baseball is most often the presenting symptom. Patients may also report decreased endurance in their arm during pitching. The signs and symptoms may be subtle, and the physician must consider this diagnosis in any baseball player complaining of these symptoms. We report on a professional baseball pitcher who was diagnosed with an axillary artery aneurysm and occlusion of the humeral circumflex artery with distal embolization that failed nonoperative treatment and required surgical resection of the aneurysm. CASE REPORT

Cross-sectional pattern of collateral vessels in patients with superficial femoral artery occlusion.

Wecksell MB, Winchester PA, Bush HL, et al. Cross-sectional pattern of collateral vessels in patients with superficial femoral artery occlusion. Invest Radiol 2001;36:422–429. rationale and objectives. The purpose of this study was to identify the cross-sectional location of collateral vessels in patients with peripheral vascular disease on three-dimensional magnetic resonance angiograms (3D MRAs) to suggest sites for intravascular or transcutaneous angiogenesis gene delivery in the lower extremity. methods.The axial locations were measured and categorized by tissue compartments, as well as by radial coordinates with respect to the femur. results.Collateral vessels in the thigh were identified in 24 of 93 consecutive patients who underwent peripheral 3D MRA. Ninety-one percent (99/109) of the observed collaterals were located near the adductor canal level of the thigh, with 78% (31/46) of these collaterals located in the fat in or surrounding the posterior muscle. conclusions.The majority of collateral vessels in the thigh are located in the fat or muscle within the posterior compartment near the femur at the level of the adductor canal.