Trans-rectal Ultrasound–coupled Spectral Optical Tomography of Total Hemoglobin Concentration Enhances Assessment of the Laterality and Progression of a Transmissible Venereal Tumor in Canine Prostate

Abstract

To evaluate whether trans-rectal spectral optical tomography of total hemoglobin concentration (HbT) can image longitudinal and lateral developments of a canine transmissible venereal tumor (TVT) in a canine prostate. A near-infrared (NIR) applicator was integrated with a trans-rectal ultrasound (TRUS) transducer to perform ultrasound (US)-coupled optical tomography of the canine prostate. Spectral detection at 785 and 830 nm enabled quantitation of HbT. Canine TVT cells were injected into the right lobe of a dog's prostate gland. Longitudinal imaging assessment of the post-injection prostate was performed by coupled US/NIR imaging over a 45-day duration. By day 7, NIR indicated TVT infiltration in the noninjected left prostatic lobe with the gray-scale US indistinct. By day 31, both NIR and gray-scale US revealed more widespread TVT involvement in the left than in the right lobe, as well as an extensive TVT mass in the caudal aspect of the gland, of which the peak HbT increased 3-fold and the mass volume grew exponentially over the 45-day duration. Increased blood supply to the mass was also observed on Doppler US. TRUS-coupled spectral optical tomography enhances assessment of the laterality and progression of prostate tumor compared with using gray-scale and Doppler TRUS.