Oximetric angiosome imaging in diabetic feet

Abstract

Purpose-To develop a noncontrast oximetric angiosome imaging approach to assess skeletal muscle oxygenation in diabetic feet.Materials and Methods-In four healthy and five subjects with diabetes, the feasibility of foot oximetry was examined using a 3T clinical magnetic resonance imaging (MRI) scanner. The subjects' feet were scanned at rest and during a toe-flexion isometric exercise. The oxygen extraction fraction of skeletal muscle was measured using a susceptibility-based MRI method. Our newly developed MR foot oximetric angiosome model was compared with the traditional angiosome model in the assessment of the distribution of oxygen extraction fraction.Results-Using the traditional angiosome during the toe-flexion exercise, the oxygen extraction fraction in the medial foot of healthy subjects increased (4.9 ± 3%) and decreased (−2.7 ± 4.4%) in subjects with diabetes (difference = 7.6%; 95% confidence interval = −13.7 ± 1.4; P = 0.02).Using the oximetric angiosome, the percent difference in the areas of oxygen extraction fraction within the 0.7-1.0 range (expected oxygen extraction fraction during exercise) between rest and exercise was higher in healthy subjects (8 ± 4%) than in subjects with diabetes (4 ± 4%; P = 0.02).Conclusion-This study demonstrates the feasibility of measuring skeletal muscle oxygen extraction fraction in the foot muscle during a toe-flexion isometric exercise. Instead of assessing oxygen extraction fraction in a foot muscle region linked to a supplying artery (traditional angiosome), the foot oximetric angiosome model assesses oxygen extraction fraction by its different levels in all foot muscle regions and thus may be more appropriate for assessing local ischemia in ulcerated diabetic feet.Foot disorders (such as ulceration, infection, and gangrene) are the leading causes of hospitalization in patients with diabetes mellitus (DM). 6 One key prognostic factor that is currently lacking in diabetic foot care is an accurate indicator of the local microvascular bed basal flow (skeletal muscle perfusion) and responsiveness (skeletal muscle oxygenation) to help guide diagnosis and intervention. HHS Public AccessThe angiosome concept, defined by Taylor and Palmer in 1987, 7 has been increasingly incorporated into endovascular procedures to treat patients with foot ulcers. [8][9][10] This angiosome model (called traditional angiosome in this project) divides the foot into three angiosomes: medial plantar, lateral plantar, and calcaneal angiosomes. These angiosomes are supplied by blood flow from medial plantar, lateral plantar, and medial calcaneal arteries, respectively. After identifying the artery responsible for perfusing the angiosome in which the ulcer is located, directed revascularization of that end-artery is undertaken to optimize healing. However, this angiographic angiosome may not be appropriate to address the local tissue perfusion that cannot be visualized by angiography, especially in patients with DM. 11 Furthermore, assessment of the effectiveness of the vascular ...

Current Issues and Interrogations in Angiosome Wound Targeted Revascularization for Chronic Limb Threatening Ischemia: A Review

“…Although without comparable and homogeneous design between series (inclusion-exclusion criteria), these studies however revealed few changes in angiosome-oriented (DR versus IR) tissue capillaries during the early stages of revascularization [21] [22] [73]. Ostensibly, these findings about the World Journal of Cardiovascular Diseases progression of capillary reperfusion after DR/WTR appear to contradict similar research by Iida et al [6] by Shiraki et al [51] by Zheng et al [74] by Kawanishi et al [75] and by Okamoto et al [76] In a systematic literature review of 1290 CLTI cases, Biancari et al [78] found that DR may enhance superior wound healing rates, if this strategy can be technically applied [78]. In the same analysis, DR limb salvage rates were, however, comparable to IR but with no statistical weight [78].…”

Grades of Below-the-Ankle Arterial Occlusive Disease following the Angiosome Perfusion: A New Morphological Assessment and Correlations with the Inframalleolar GVG Stratification in CLTI Patients

“…Previous clinical experience including our published research revealed that specific foot vascular territories with ischemic wounds may address different stages of atherosclerotic occlusive lesions of "source arteries" and appended collaterals 7,[34][35][36][37][38][39] , and belongs to a larger ongoing investigation regarding the anatomical and hemodynamic aspects of BTA vasculature in CLTI. Though doubts about the real clinical benefit of WDR for both bypass and EVT have been raised in contemporary literature 1-8, 10, 19-21, 32, 37 , using modern microcirculatory diagnostic methods with valuable topographic information 10,19,40,42 . While some authors have found the assessment of anatomical 6,10,16,28 and physiological 16,40,41 angiosomal flow by MRI oximetry 40 , trans-cutaneous laser Doppler 16,28 , or peripheral SPECT-Scan perfusion 10,[41][42][43] useful, others have questioned the utility of topographic reperfusion using white-light tissue spectrophotometry 44 , and low-frequency oscillations analyzed by diffuse speckle contrast analysis 45 .…”

“…Though doubts about the real clinical benefit of WDR for both bypass and EVT have been raised in contemporary literature 1-8, 10, 19-21, 32, 37 , using modern microcirculatory diagnostic methods with valuable topographic information 10,19,40,42 . While some authors have found the assessment of anatomical 6,10,16,28 and physiological 16,40,41 angiosomal flow by MRI oximetry 40 , trans-cutaneous laser Doppler 16,28 , or peripheral SPECT-Scan perfusion 10,[41][42][43] useful, others have questioned the utility of topographic reperfusion using white-light tissue spectrophotometry 44 , and low-frequency oscillations analyzed by diffuse speckle contrast analysis 45 . The clinical value of all these studies that support or refute specific postoperative angiosomal microcirculatory changes is indisputable.…”