Objective: To investigate the value of the resistive index (RI) of intratesticular arteries, and to establish diagnostic criteria for normal and pathological sperm counts on the basis of quantitative colour Doppler ultrasonography (CDUS), as the assessment of the testicular RI is widely used to measure intratesticular blood flow.
Patients and methods: In all, 160 men (aged 22-43 years, 320 testicles) were prospectively investigated; 80 had a normal and 80 a pathological sperm count, the latter having mild oligoasthenozoospermia. The RI was measured using a high-frequency Doppler ultrasound probe (14 MHz), three times on each testicle at an intratesticular artery in the upper, middle and lower testicular pole. The testicular volume was also measured by US. The RI values were compared between patients with normal and pathological sperm counts, and were compared statistically with testicular volumes. In addition, blood samples were obtained for DNA extraction, chromosome analysis and hormonal evaluations.
Results: Patients with normal sperm counts had a mean (sd) RI of 0.54 (0.05) and a mean testicular volume of 18.7 (5.2) mL, the respective values in those with pathological sperm counts were 0.68 (0.06) and 16.8 (6.0) mL, with a significantly greater RI in the latter (P < 0.001), but with no statistically significant difference in testicular volume between the groups (P > 0.05).
Conclusion: These preliminary data suggest that an RI of >0.6 might be suggestive of a pathological sperm count in andrological patients. The intratesticular RI as measured by CDUS seems to be a reliable indicator for routine clinical use to identify subfertile men.