Radiotracer-Based Perfusion Imaging of Patients With Peripheral Arterial Disease

PAD patients (n=100) with critical limb ischemia, previously diagnosed diabetes, and
non-healing foot wounds who are scheduled to undergo lower extremity revascularization
procedures will be recruited. Patients will be screened using a standard medical history
questionnaire and a physical activity questionnaire. Once their questionnaires are reviewed,
individuals who meet inclusion criteria will proceed with standard PAD screening, which will
include Ankle-Brachial Indices (ABIs) and Toe-Brachial Indices (TBIs) of both lower
extremities. Patients will undergo SPECT/CT perfusion imaging prior to their
revascularization procedure and 1-5 days following revascularization. Subjects will receive
an intravenous injection of a standard clinical dose of radiotracer
(technetium-99m-tetrofosmin) for both imaging sessions. A low-dose CT scan will be performed
immediately after each SPECT image acquisition for the purposes of attenuation correction and
regional analysis of radiotracer uptake. Clinical outcomes will be evaluated for up to 12
months after the imaging study to assess the prognostic value of SPECT/CT perfusion imaging
for predicting subsequent outcomes.

Inclusion Criteria:

1. At least 18 years of age

2. Evidence of significant obstructive disease for one or multiple lower extremity
arteries, as identified by prior ABI, TBI, CT angiography, ultrasound, or MR imaging.

3. Scheduled for endovascular revascularization or surgical bypass of one or both lower
extremities.

4. Previously diagnosed diabetes mellitus (type I or II), based on any of the following
criteria: fasting plasma glucose great than 126 mg/dl on 2 separate occasions,
glycated hemoglobin (HbA1c) equal to or greater than 6.5%, fasting plasma glucose
greater than 200 mg/dl 2 hours following an oral glucose tolerance test on 2 separate
occasions, or fasting plasma glucose and HbA1c above normal limits on same visit.

Exclusion Criteria:

1. Unable to give informed consent or follow-up

2. Pregnant or nursing

3. Under the age of 18

4. No history of peripheral arterial disease or diabetes mellitus