Magnetic Resonance Evaluation of Peripheral Arterial Disease

Arterial Duplex Ultrasound is the Most Cost-Effective, Noninvasive Diagnostic Imaging Modality before Treatment of Lower-Extremity Arterial Occlusive Disease

Introduction

Multiple noninvasive imaging modalities (duplex ultrasound, magnetic resonance angiography, and computed tomographic angiography) are now available for diagnostic evaluation of lower-extremity arterial occlusive disease (LEOD). This study was performed to determine the effectiveness of duplex ultrasound as the primary diagnostic imaging test before endovascular treatment and to estimate the potential cost-savings compared with the use of other technologies.

Methods

The diagnostic evaluations of all patients treated for LEOD by a single vascular specialist between July 2004 and February 2008 were reviewed. The medical records were reviewed for the initial noninvasive diagnostic imaging study, type of intervention, and patency of revascularization. Medicare reimbursement rates (2007) for each imaging modality were used to compare costs of diagnostic testing.

Results

A total of 128 endovascular interventions were performed in 89 patients. Arterial duplex imaging was the primary and only diagnostic study performed prior to endovascular treatment in 108 (84%) of procedures. If preintervention magnetic resonance angiography or computed tomographic angiography had been used in these patients instead of duplex, the costs for diagnostic imaging alone would have increased by $96,064 and $44,762, respectively.

Conclusion

Arterial duplex ultrasound can be effectively used as the preferred modality for noninvasive imaging of LEOD, resulting in substantial cost savings.

Non-contrast-enhanced peripheral MR angiography using velocity-selective excitation

PURPOSE

To develop a new non-contrast-enhanced peripheral MR angiography that provides a high contrast angiogram without using electrocardiography triggering and saturation radiofrequency pulses.

METHODS

A velocity-selective excitation technique is used in conjunction with the golden-angle radial sampling scheme. The signal amplitude varies according to the velocity of the flow by the velocity-selective excitation technique. Because the arterial blood velocity varies depending on the cardiac phase, the acquired data can be classified into systolic and diastolic phase based on the signal amplitude of the artery. Two images are then reconstructed from the systolic and diastolic phase data, respectively, and an image reflecting the differences between the two images is obtained to eliminate background and vein signals. The performance of the proposed method was compared with the quiescent-interval single shot (QISS) in eight healthy subjects and an elderly subject.

RESULTS

The proposed method generated fewer residual venous and background signals than the QISS. Furthermore, the maximum intensity projection images, the relative contrast, and the apparent contrast-to-noise ratio results showed that the proposed method produced a better contrast than the QISS.

CONCLUSIONS

The proposed non-contrast-enhanced peripheral MR angiography technique can provide a high contrast angiogram without the use of electrocardiography triggering and saturation radiofrequency pulses. Magn Reson Med 79:779-788, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Dynamic MR angiography of upper extremity vascular disease: pictorial review

Unlike peripheral lower extremity vascular disease, upper extremity vascular disease is relatively uncommon. While atherosclerosis and embolic disease are the most common causes of upper extremity ischemia, a wide variety of systemic diseases and anatomic abnormalities can affect the upper extremity. Upper extremity ischemia poses a significant diagnostic and therapeutic challenge for both clinicians and radiologists. Although history and physical examination remain the mainstays of diagnosis, imaging can be vital in confirming suspected disease and guiding treatment planning. Digital subtraction angiography is often the preferred method for detection of upper extremity vascular disease, particularly for characterization of complex arteriovenous anatomy such as in vascular malformations and for evaluation of dialysis fistulas and grafts. However, this modality is invasive, requires iodinated contrast agents and radiation, and may fail to demonstrate significant extraluminal disease. More recently, magnetic resonance (MR) angiography techniques have made important advances, permitting higher temporal and spatial resolution that is preferable for diagnosing upper extremity vascular disorders. In this review, the authors present an overview of upper extremity MR angiography techniques and protocols, revisit the often variable vascular anatomy of the arm and hand, and offer examples of various pathologic entities diagnosed with MR angiography. Finally, several imaging pitfalls that one must be aware of for accurate diagnosis are illustrated and reviewed.