In-Kyong Kim

Dynamic diffuse optical tomography imaging of peripheral arterial disease.

Peripheral arterial disease (PAD) is the narrowing of arteries due to plaque accumulation in the vascular walls. This leads to insufficient blood supply to the extremities and can ultimately cause cell death. Currently available methods are ineffective in diagnosing PAD in patients with calcified arteries, such as those with diabetes. In this paper we investigate the potential of dynamic diffuse optical tomography (DDOT) as an alternative way to assess PAD in the lower extremities. DDOT is a non-invasive, non-ionizing imaging modality that uses near-infrared light to create spatio-temporal maps of oxy- and deoxy-hemoglobin in tissue. We present three case studies in which we used DDOT to visualize vascular perfusion of a healthy volunteer, a PAD patient and a diabetic PAD patient with calcified arteries. These preliminary results show significant differences in DDOT time-traces and images between all three cases, underscoring the potential of DDOT as a new diagnostic tool.

Measuring peripheral vascular reactivity with diffusive optical imaging

Diffuse optical imaging of the peripheral vascular reactivity is implemented at the major arteries of the foot. Transmitted light intensities are recorded in response to vascular occlusions induced by pressure cuffs. These dynamic measurements promise to help identify various peripheral vascular diseases.

Imaging of vascular dynamics within the foot using dynamic diffuse optical tomography to diagnose peripheral arterial disease

Peripheral Arterial Disease (PAD) is the narrowing of the functional area of the artery generally due to atherosclerosis. It affects between 8-12 million people in the United States and if untreated this can lead to ulceration, gangrene and ultimately amputation. The current diagnostic method for PAD is the ankle-brachial index (ABI). The ABI is a ratio of the patient’s systolic blood pressure in the foot to that of the brachial artery in the arm, a ratio below 0.9 is indicative of affected vasculature. However, this method is ineffective in patients with calcified arteries (diabetic and end-stage renal failure patients), which falsely elevates the ABI recording resulting in a false negative reading. In this paper we present our results in a pilot study to deduce optical tomography’s ability to detect poor blood perfusion in the foot. We performed an IRB approved 30 patient study, where we imaged the feet of the enrolled patients during a five stage dynamic imaging sequence. The patients were split up into three groups: 10 healthy subjects, 10 PAD patients and 10 PAD patients with diabetes and they were imaged while applying a pressure cuff to their thigh. Differences in the magnitude of blood pooling in the foot and rate at which the blood pools in the foot are all indicative of arterial disease.

Two-Stage Hybrid Repair of a Complex Symptomatic Celiac Aneurysm

We report the case of a novel 2-stage hybrid repair of a complex celiac artery aneurysm. The patient was a 42-year-old man with a proximal celiac artery aneurysm giving rise to distinct right and left hepatic arterial branches. Repair was performed using a staged approach. First, a bifurcated aortohepatic bypass was constructed to the common and left hepatic arteries. After recovering from surgery, he underwent percutaneous embolization of the aneurysm. Completion angiograms demonstrated flow into all celiac branches with successful thrombosis of the aneurysm. At 12-month follow-up, the patient had remained symptom-free with patent bypass grafts and complete aneurysm exclusion. We describe the treatment option we used, which involves repair of a complex celiac aneurysm using a 2-stage, open, endovascular approach.

Diabetic Considerations in Aortoiliac Disease

Aortoiliac atherosclerotic disease has a unique disease process, presentation, progress, and treatment and should be viewed as a distinct entity from the infrainguinal and infrapopliteal atherosclerosis. At a cursory look, diabetes appears to mainly affect the tibial vessels. Although not as well described, diabetes has a large impact on the proximal vessels at multiple levels. This chapter reviews the pathogenesis, epidemiology, diagnosis, and treatment of aortoiliac disease as it pertains to the diabetic population.

Detecting lower extremity vascular dynamics in patients with peripheral artery disease using diffuse optical tomography

Peripheral Artery Disease (PAD) affects over 10 million Americans and is associated with significant morbidity and mortality. While in many cases the ankle-brachial index (ABI) can be used for diagnosing the disease, this parameter is not dependable in the diabetic and elderly population. These populations tend to have calcified arteries, which leads to elevated ABI values. Dynamic optical tomography (DDOT) promises to overcome the limitations of the current diagnostic techniques and has the potential to initiate a paradigm shift in the diagnosis of vascular disease. We have performed initial pilot studies involving 5 PAD patients and 3 healthy volunteers. The time traces and tomographic reconstruction obtained from measurements on the feet show significant differences between healthy and affected vasculatures. In addition, we found that DOT is capable of identifying PAD in diabetic patients, who are misdiagnosed by the traditional ABI screening.