What should I request for mobile imaging of suspected lower extremity vascular pathology?

Mobile Imaging for Suspected Lower Extremity Vascular Pathology

Request a mobile duplex Doppler ultrasound of the lower extremity, which is the most practical and appropriate portable imaging modality for evaluating suspected lower extremity vascular disease. 1, 2

Why Duplex Doppler Ultrasound is the Mobile Option

Duplex Doppler ultrasound is the only truly portable imaging modality that can be performed at bedside or in mobile settings for lower extremity vascular evaluation. 1, 2 The key advantages include:

• Noninvasive, portable, and can be quickly performed and repeated without radiation risk 1
• Evaluates both arterial and venous pathology in a single examination 2, 3
• Provides real-time hemodynamic information through waveform analysis and velocity measurements 4, 5

What to Specifically Request

For Arterial Pathology

Request: "Mobile arterial duplex ultrasound with segmental Doppler waveform analysis and ankle-brachial index (ABI) measurement" 4, 2

This examination should include:

• Peak systolic velocity (PSV) measurements to detect stenoses ≥70% (PSV ≥200 cm/s indicates significant stenosis) 5
• Waveform analysis to identify monophasic patterns indicating upstream obstruction 4
• ABI calculation to quantify perfusion (normal >0.90; <0.40 indicates critical ischemia) 2

For Venous Pathology

Request: "Mobile comprehensive venous duplex ultrasound from thigh to ankle with Doppler at selected sites" 1, 2

This examination should include:

• Compression ultrasonography of the common femoral, deep femoral, popliteal, tibial, and peroneal veins 1, 3
• Evaluation of calf muscular veins and superficial venous system 3
• Doppler waveform assessment for respiratory phasicity and cardiac pulsatility 4

Critical Limitations of Mobile Ultrasound

Be aware that ultrasound has significant diagnostic limitations that may require subsequent cross-sectional imaging:

• Limited by severe vascular calcifications common in patients with chronic kidney disease 6
• Operator-dependent with difficulty evaluating deep vessels 6
• Poor visualization of iliac vessels and abdominal aorta, precluding evaluation of proximal pathology 1
• Cannot adequately assess for alternative diagnoses such as masses, hematomas, or soft tissue pathology requiring CT or MRI 3

When Mobile Ultrasound is Insufficient

If acute limb ischemia is suspected (sudden onset cold, painful leg with motor/sensory changes), mobile ultrasound is inadequate. 1, 6 In this emergent scenario:

• CTA of the abdomen/pelvis with bilateral lower extremity runoff is the appropriate initial imaging 1, 6
• Time is tissue—delays beyond 4-6 hours increase amputation risk 6
• Start anticoagulation immediately before obtaining definitive imaging 6

Practical Algorithm for Mobile Imaging Request

For suspected chronic arterial disease (claudication, rest pain):

• Request mobile arterial duplex with ABI 2, 5

For suspected acute or chronic venous disease (unilateral swelling, bilateral edema):

• Request comprehensive mobile venous duplex from thigh to ankle 1, 2, 3

For mixed presentation or unclear etiology:

• Request combined arterial and venous mobile duplex examination 2, 3

For acute limb ischemia (sudden onset, cold, pulseless, paralysis):

• Do not rely on mobile ultrasound—transport patient for emergent CTA 1, 6