COMPARISON OF RADIONUCLIDE SCROTAL BLOOD-POOL INDEX VERSUS GONADAL VENOGRAPHY IN THE DIAGNOSIS OF VARICOCELE

The purpose of our study was to assess the value of a radionuclide scr otal blood-pool index (SBPI) in diagnosing and grading clinical and su bclinical varicocele. Methods: Scrotal scans were performed on 1360 in fertile patients. Thirty fertile patients with a normal scrotum on pal pation served as controls. The patients' red blood cells were labeled in vivo by administration of stannous ions of pyrophosphate followed b y the intravenous administration of Tc-99m-pertechnetate, The scans in itially were inspected visually and, when bilateral varicocele was exc luded, a computerized analysis of the ratio of the blood-pool activity in each hemiscrotum (SBPI) permitted accurate grading of the varicoce le. A subgroup of 224 patients was selected randomly and had gonadal v enography. The results of physical examination, scrotal scan, gonadal venography and semen analysis were compared. Results: Normal Values of SBPI (0.9-1.1) were derived from the control group. There was a 93.5% correlation between palpation and SBPI grade in diagnosing palpable v aricocele. When compared to gonadal venography, subclinical varicocele was demonstrated by scrota[ scan in 54.8% of infertile male patients with abnormal semen analysis, normal female partners and no other caus e of infertility. Of these patients, 32.6% had, unexpectedly, Grade 2 or 3 varicocele. Right and bilateral varicocele were demonstrated thre e times as often by scrotal scan than by palpation. SBPI was accurate in diagnosing recurrent varicocele but there was a low correlation (61 .1%) between SBPI and gonadal venography grade. There was a high corre lation between SBPI grade and sperm analysis grade. Conclusion: SBPI g rading of varicocele was validated as an accurate, quantitative and no ninvasive method of grading varicocele, equivalent to the grading syst em by palpation in a large group of infertile patients. The main contr ibution of SBPI was in detecting and grading subclinical varicocele in infertile patients with no other cause of infertility. SBPI also was accurate in diagnosing but not in grading recurrent varicocele.