In vivo, noninvasive functional measurements of bone sarcoma using diffuse optical spectroscopic imaging

Abstract

Diffuse optical spectroscopic imaging (DOSI) is an emerging near-infrared imaging technique that noninvasively measures quantitative functional information in thick tissue. This study aimed to assess the feasibility of using DOSI to measure optical contrast from bone sarcomas. These tumors are rare and pose technical and practical challenges for DOSI measurements due to the varied anatomic locations and tissue depths of presentation. Six subjects were enrolled in the study. One subject was unable to be measured due to tissue contact sensitivity. For the five remaining subjects, the signal-to-noise ratio, imaging depth, optical properties, and quantitative tissue concentrations of oxyhemoglobin, deoxyhemoglobin, water, and lipids from tumor and contralateral normal tissues were assessed. Statistical differences between tumor and contralateral normal tissue were found in chromophore concentrations and optical properties for four subjects. Low signal-to-noise was encountered during several subject's measurements, suggesting increased detector sensitivity will help to optimize DOSI for this patient population going forward. This study demonstrates that DOSI is capable of measuring optical properties and obtaining functional information in bone sarcomas. In the future, DOSI may provide a means to stratify treatment groups and monitor chemotherapy response for this disease.

Characterization of bony anatomic regions in pediatric and adult healthy volunteers using diffuse optical spectroscopic imaging

“…A custom LabVIEW (National Instruments, Austin, Texas) code was developed to control the system. The handheld probe was the same as used by Peterson et al 13 All measurements for this study were taken with a source-detector separation of 28 mm.…”

“…A DOSI measurement procedure developed for bony measurements used in our prior published study was modified for measurements taken in this study. 13 In this study, measurements were made on the left and right medial distal humerus, distal femur, and proximal tibia.…”

“…This differs from some prior reports that demonstrated hemoglobin differences between bony locations. 13,17 For example, Sekar et al 17,30 used time-resolved diffuse optical spectroscopy to measure the proximal femur (trochanter), distal and proximal radius, distal and proximal ulna, and calcaneous. They found statistically significant differences in oxyhemoglobin, deoxyhemolgobin, and oxygen saturation between many of these sites.…”

“…The use of DOSI and similar techniques for earlier detection, prevention, and monitoring of bone pathologies is more recent, and the variation among anatomic sites, sex, and age is only beginning to be characterized. 2,[11][12][13] We recently evaluated the feasibility of using DOSI to measure sarcomas in pediatric patients for the first time. 13 Bone and soft tissue sarcomas comprise 12% of all childhood cancers and 5-year disease-free survival and overall survival for localized bone sarcomas have remained at ∼70% for the last 40 years, representing a major clinical need.…”

“…2,[11][12][13] We recently evaluated the feasibility of using DOSI to measure sarcomas in pediatric patients for the first time. 13 Bone and soft tissue sarcomas comprise 12% of all childhood cancers and 5-year disease-free survival and overall survival for localized bone sarcomas have remained at ∼70% for the last 40 years, representing a major clinical need. 14,15 The optical characterization of sarcomas may provide a new means to diagnose and track treatment efficacy in this patient population.…”