Assessment of chronic limb threatening ischemia using thermal imaging

Tomppa Pakarinen; Atte Joutsen; Niku Oksala; Antti Vehkaoja

doi:10.1016/j.jtherbio.2023.103467

Assessment of chronic limb threatening ischemia using thermal imaging

J Therm Biol. 2023 Feb:112:103467. doi: 10.1016/j.jtherbio.2023.103467. Epub 2023 Jan 12.

Authors

Tomppa Pakarinen¹, Atte Joutsen², Niku Oksala³, Antti Vehkaoja⁴

Affiliations

¹ Faculty of Medicine and Health Technology, Tampere University, Postal: Tampereen Yliopisto, Korkeakoulunkatu 3, 33720, Tampere, Finland. Electronic address: tomppa.pakarinen@tuni.fi.
² Department of Medical Physics, Medical Imaging Center, Tampere University Hospital, Postal: Sädetie 6, 33520, Tampere, Finland. Electronic address: atte.joutsen@pshp.fi.
³ Faculty of Medicine and Health Technology, Tampere University, Postal: Tampereen Yliopisto, Korkeakoulunkatu 3, 33720, Tampere, Finland; Vascular Surgery and Procedural Radiology, Tampere University Hospital, Postal: Elämänaukio 2, 33520, Tampere, Finland. Electronic address: niku.oksala@pshp.fi.
⁴ Faculty of Medicine and Health Technology, Tampere University, Postal: Tampereen Yliopisto, Korkeakoulunkatu 3, 33720, Tampere, Finland. Electronic address: antti.vehkaoja@tuni.fi.

PMID: 36796912
DOI: 10.1016/j.jtherbio.2023.103467

Abstract

Objectives: Current chronic limb threatening ischemia (CLTI) diagnostics require expensive equipment, using ionizing radiation or contrast agents, or summative surrogate methods lacking in spatial information. Our aim is to develop and improve contactless, non-ionizing and cost-effective diagnostic methods for CLTI assessment with high spatial accuracy by utilizing dynamic thermal imaging and the angiosome concept.

Approach: Dynamic thermal imaging test protocol was suggested and implemented with a number of computational parameters. Pilot data was measured from 3 healthy young subjects, 4 peripheral artery disease (PAD) patients and 4 CLTI patients. The protocol consists of clinical reference measurements, including ankle- and toe-brachial indices (ABI, TBI), and a modified patient bed for hydrostatic and thermal modulation tests. The data was analyzed using bivariate correlation.

Results: The thermal recovery time constant was on average higher for the PAD (88%) and CLTI (83%) groups with respect to the healthy young subjects. The contralateral symmetry was high for the healthy young group and low for the CLTI group. The recovery time constants showed high negative correlation to TBI (ρ = -0.73) and ABI (ρ = -0.60). The relation of these clinical parameters to the hydrostatic response and absolute temperatures (|ρ|<0.3) remained unclear.

Conclusion: The lack of correlation for absolute temperatures or their contralateral differences with the clinical status, ABI and TBI disputes their use in CLTI diagnostics. Thermal modulation tests tend to augment the signs of thermoregulation deficiencies and accordingly high correlations were found with all reference metrics. The method is promising for establishing the connection between impaired perfusion and thermography. The hydrostatic modulation test requires more research with stricter test conditions.

Keywords: Blood perfusion; Chronic limb threatening ischemia; Dynamic imaging; Peripheral artery disease; Thermal imaging.

MeSH terms

Ankle
Chronic Limb-Threatening Ischemia*
Humans
Ischemia / diagnostic imaging
Lower Extremity / blood supply
Peripheral Arterial Disease* / diagnostic imaging
Retrospective Studies
Risk Factors