IN VIVO TRANS-RECTAL ULTRASOUND-COUPLED NEAR-INFRARED OPTICAL TOMOGRAPHY OF INTACT NORMAL CANINE PROSTATE

This is the first tomography-presentation of the optical properties of a normal canine prostate,in vivo,in its native intact environment in the pelvic canal.The imaging was performed by trans-rectal near-infrared(NIR)optical tomography in steady-state measurement at 840 nm on three sagittal planes across the right lobe,middle-line,and left lobe,respectively,of the prostate gland.The NIR imaging planes were position-correlated with concurrently applied trans-rectal ultrasound,albeit there was no spatial prior employed in the NIR tomography reconstruction.The reconstructed peak absorption coefficients of the prostate on the three planes were 0.014,0.012,and 0.014mm^(−1).The peak reduced scattering coefficients were 5.28,5.56,and 6.53 mm^(−1).The peak effective attenuation coefficients were 0.45,0.43,and 0.50 mm^(−1).The absorption and effective attenuation coefficients were within the ranges predictable at 840 nm by literature values which clustered sparsely from 355 nm to 1064 nm,none of which were performed on a canine prostate with similar conditions.The effective attenuation coefficients of the gland were shown to be generally higher in the internal aspects than in the peripheral aspects,which is consistent with the previous findings that the urethral regions were statistically more attenuating than the capsular regions.

In vivo percutaneous reflectance spectroscopy of fatty liver development in rats suggests that the elevation of the scattering power is an early indicator of hepatic steatosis

This study assessed whether there was a scat tering spectral mar ker quantifiable by reflectance measurements that could indicate early development of hepatic steatosis in rats for potential applications to pre procurement organ evaluation.Sixteen rats were fed a methionine choline-deficient(MCD)diet and eight rats were fed a normal diet.Direct assessment of the liver parenchyma of rats in vivo was performed by percut aneous reflect ance spectroscopy using a single fiber probe at the beginning of diet-intake and arbitrary post-diet-intake times up to 11 weeks to render longitudinal comparison.Histological sampling of the liver over the duration of diet adm inistration was performed on two MCD diet treated rats and one control rat eutha-nized after reflectance spectroscopy measurement.The images of hematoxylin/eosin-stained liver specimens were analyzed morphometrically to evahuate the lipid size changes associated with the level of steatosis.The MCD-diet-treated group(n=16)had mild steatosis in seven rats,moderate in three rats,severe in six rats,and no other significant pathology.No control rats(n=8)developed hepatic steatosis.Among the parameters retrieved from per-SfS,only the scat tering power(can be either positive or negative)appeared to be statist ically diferent between MCD-treated and control livers.The scattering power for the 16 MCD-diet-treated livers at the time of euthanasia and presenting various levels of steatosis was 033±0.21,in comparison to 0.036±0.25 of the eight control livers(p=0.0189).When evaluated at days 12 and 13 combined,the scattering power of the 16 MCD-diet-treated livers was 032±0.17,in comparison to 0.10±0.11 of the eight control livers(p=0.0017).All of four MCD-treated livers harvested at days 12 and 13 presented mild steatosis with sub-micron size lipid droplets,even though none of the MCD-treated livers were sonogr aphically remarkable for fatty changes.The elevation of the scattering power may be a valuable marker indicating early hepatic steatosis before the steatosis is sonographically detectable.