P-31 MR spectroscopy in assessing testicular torsion: rat model

To develop phosphorus-31 magnetic resonance (MR) spectroscopy as an indicator of testicular viability, unilateral 720 degrees torsion of the spermatic cord was performed in 11 Copenhagen rats. In six of 11 rats, detorsion was done 1 hour later. The authors used special surface coils to obtain P-31 MR spectra (at 2 T) from both tests, then correlated MR findings with those from gross morphologic and histologic examination. In the normal testis, P-31 MR spectra had prominent phosphomonoester (PME) and adenosinetriphosphate (ATP) peaks. Testicular torsion dramatically reduced ATP to almost undetectable levels and significantly decreased the PME/Pi at 1 hour (1.18 +/- 0.22) in nine rats. In two rats, however, no spectral changes were present. Of the six rats in which detorsion was performed, three showed immediate regeneration of ATP and a normal PME/Pi (2.87 +/- 0.06) 3 hours later; testicles in the other three rats did not recover (PME/Pi = 0.72 +/- 0.01). Because gross morphologic observations and histologic findings prior to detorsion were unable to differentiate viable from nonviable tests, these preliminary data suggest P-31 MR spectroscopy may help clinicians diagnose testicular torsion and assess testicular viability.