Noninvasive assessment of testicular torsion in rabbits using frequency-domain near-infrared spectroscopy: prospects for pediatric urology

Abstract

We present a quantitative near-IR spectroscopy study of the absolute values of oxygen saturation of hemoglobin before and after surgically induced testicular torsion in adult rabbits. Unilateral testicular torsions (0, 540, or 720 deg) on experimental testes and contralateral sham surgery on control testes are performed in four adult rabbits. A specially designed optical probe for measurements at multiple source-detector distances and a commercial frequency-domain tissue spectrometer are used to measure absolute values of testicular hemoglobin saturation. Our results show: (1) a consistent baseline absolute tissue hemoglobin saturation value of 78+/-5%, (2) a comparable tissue hemoglobin saturation of 77+/-6% after sham surgery, and (3) a significantly lower tissue hemoglobin saturation of 36+/-2% after 540- and 720-deg testicular torsion surgery. Our findings demonstrate the feasibility of performing frequency-domain, multidistance near-IR spectroscopy for absolute testicular oximetry in the assessment of testicular torsion. We conclude that near-IR spectroscopy has potential to serve as a clinical diagnostic and monitoring tool for the assessment of absolute testicular hemoglobin desaturation caused by torsion, with the possibility of serving as a complement to conventional color and spectral Doppler ultrasonography.

Cerebral perfusion and oxygenation are impaired by folate deficiency in rat: Absolute measurements with noninvasive near-infrared spectroscopy

“…To overcome these limitations, we developed a noninvasive multi-distance NIRS system that does not rely on any calibration procedures or estimated predefined factors. We separately measure the absorption and reduced scattering coefficients in cerebral tissue and translate the absorption coefficients at two wavelengths (690 and 830 nm) into absolute concentration and saturation of hemoglobin as shown in our recent study (Hallacoglu et al , 2009). The system, which incorporates a commercially available frequency-domain NIRS device and other components, and integrates them with our software, makes it possible to noninvasively, reproducibly and robustly measure hemoglobin-related parameters in anesthetized rats at rest and in response to physiologic challenges.…”

Near‐infrared spectroscopy in the diagnosis of testicular torsion: valuable modality or waste of valuable time? A systematic review

“…The remaining 17 articles where fully reviewed. Nine articles were finally selected for inclusion in the systematic review after excluding a further eight irrelevant articles (Fig. ).…”

“…Five of the studies had human participants . The four animal studies used sheep, and rabbits and rats …”

Optical diagnosis of testicular torsion: feasibility and methodology

“…8 Colier first used NIRS to study testicular hemodynamics, by measuring active testicular blood volume using a continuous wave (CW) instrument before and after spermatic cord occlusion in boars. 9 Capraro used testicular tissue oxygen saturation (StO2) measurement to investigate the effect of experimental testicular torsion and surgical relief of torsion in sheep; 10 CW NIRS-derived testicular StO2 has also been measured in a rat model of surgically induced and relieved torsion; 11 and in a similar study in rabbits absolute values of testicular StO2 were obtained using a frequency domain spectrometer with a specially designed optical probe. 12 A dual wavelength CW NIRS device with light emitting diodes (LEDs) as the light source was developed and tested in a rat model using comparison of the ratio of the average intensities of transmitted light at 660 nm to 940 nm obtained in transmission geometry to diagnose torsion.…”