Magnetic Resonance Imaging Techniques in Peripheral Arterial Disease

Abstract

Significance: Peripheral arterial disease (PAD) leads to a significant burden of morbidity and impaired quality of life globally. Diabetes is a significant risk factor accelerating the development of PAD with an associated increase in the risk of chronic wounds, tissue, and limb loss. Various magnetic resonance imaging (MRI) techniques are being increasingly acknowledged as useful methods of accurately assessing PAD. Recent Advances: Conventionally utilized MRI techniques for assessing macrovascular disease have included contrast enhanced magnetic resonance angiography (MRA), noncontrast time of flight MRA, and phase contrast MRI, but have significant limitations. In recent years, novel noncontrast MRI methods assessing skeletal muscle perfusion and metabolism such as arterial spin labeling (ASL), blood-oxygen-level dependent (BOLD) imaging, and chemical exchange saturation transfer (CEST) have emerged. Critical Issues: Conventional non-MRI (such as ankle-brachial index, arterial duplex ultrasonography, and computed tomographic angiography) and MRI based modalities image the macrovasculature. The underlying mechanisms of PAD that result in clinical manifestations are, however, complex, and imaging modalities that can assess the interaction between impaired blood flow, microvascular tissue perfusion, and muscular metabolism are necessary. Future Directions: Further development and clinical validation of noncontrast MRI methods assessing skeletal muscle perfusion and metabolism, such as ASL, BOLD, CEST, intravoxel incoherent motion microperfusion, and techniques that assess plaque composition, are advancing this field. These modalities can provide useful prognostic data and help in reliable surveillance of outcomes after interventions.

Keywords: arterial spin labeling; blood-oxygen-level dependent imaging; dynamic contrast-enhanced imaging; noncontrast magnetic resonance angiography; peripheral arterial disease; quiescent-interval single-shot.

Christopher M. Kramer, MD

Figure 1.

Contrast-enhanced magnetic resonance angiography of the lower extremity vasculature in a patient with PAD. PAD, peripheral arterial disease.

Figure 2.

Principle of TOF-MRA in a healthy patient. Reprinted from Leiner with permission from Wolters Kluwer Health. TOF-MRA, time of flight magnetic resonance angiography.

Figure 3.

QISS noncontrast magnetic resonance angiography. Examples of arteriogram (A) and venogram (B) in a healthy patient. Reprinted from Cavallo et al. with permission from Wolters Kluwer Health. QISS, quiescent-interval single-shot.

Figure 4.

Three-dimensional fast spin echo magnetic resonance angiography of the foot, coronal (A) and coronal sagittal image rotated 6 degrees (B). Reprinted from Edelman et al. with permission from the Radiological Society of North America.

Figure 5.

Velocity-selective magnetic resonance angiography and DSA images in a patient with mild right sided claudication. The MR angiogram shows excellent agreement with the DSA image in identifying mild intermittent narrowing in the right femoral artery (arrowheads) and occlusion of the right anterior tibial artery (arrow). Reprinted from Shin et al. with permission from John Wiley and Sons. DSA, digital subtraction angiography.

Figure 6.

Quantitative analysis of dynamic first-pass contrast-enhanced calf muscle perfusion at peak exercise. Axial spin-recovery (left upper panel) and inversion-recovery (left lower panel) images during contrast infusion at the level of the mid-calf with regions of interest drawn. Note regional enhancement in the anterior tibialis and soleus muscle regions (arrows, lower left panel). Time-intensity curves (right) from the soleus and the labeled artery (circle, left lower panel) are shown. AIF, arterial input function; TIF, tissue input function.

Figure 7.

Pulsed arterial spin-labeling of a calf in a patient with peripheral arterial disease after peak exercise showing increased flow in the anterior tibialis and peroneus longus muscles (black arrows).

Figure 8.

Sagittal intravoxel incoherent motion microperfusion parametric map of flow-related pseudo-diffusion inside the capillary network in a patient with critical limb ischemia of the right lower extremity (A) and a normal patient (B). Reprinted from Galanakis et al. with permission from the British Institute of Radiology.

Figure 9.

Chemical exchange saturation transfer of the calf in a normal and PAD patient acquired immediately after exercise with corresponding decay curves. Note the delay in reaching baseline deep blue and slower decay time in the patient with PAD compared to the normal subject.

Figure 10.

Representative sequential images from the superficial femoral artery (vessel with star) of a subject with mild to moderate peripheral artery disease with both the luminal (blue arrow) and adventitial border (yellow arrow) clearly delineated. Note the slice to slice variation in plaque morphology.