Diffusion tensor imaging as an adjunct tool for the diagnosis of varicocele

Abstract

A noninvasive imaging technique providing information about testicular dysfunction in testes with varicocele would be useful. The aim is to measure the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in testes of infertile men with varicocele and to assess interobserver agreement. Sixteen infertile men with varicocele and 14 age‐matched controls underwent 1.5 T diffusion tensor imaging (DTI) MRI. Testicular ADC and FA were measured by two radiologists independently. Parametric and nonparametric statistical tests were applied to compare between the ADC and FA of testes with varicocele and normal testes. Interobserver agreement was evaluated. The interobserver variability for ADC (0.915) and FA (0.948) was very good. No differences in ADC (p = 0.294) were found between the two groups. FA was significantly lower in testes with varicocele compared to age‐matched controls (p < 0.001). An optimal cut‐off of FA 0.08 was found for the diagnosis of varicocele (sensitivity = 88%, specificity = 93.5%, positive predictive value = 91.6% and negative predictive value = 90.6%). Based on our results, FA is useful for the diagnosis of testes in infertile men with varicocele, with very good interobserver agreement. Therefore, DTI may be used as a noninvasive imaging tool in the work‐up of varicocele.

When to ask for an MRI of the scrotum

“…A negative correlation between ADC and spermatic vein diameter and a positive correlation between ADC and semen analysis results has been noted in men with varicocele 93,96,101,103 . Moreover, FA represents another reliable parameter for the detection of testes with clinical varicocele, with an optimal cut‐off of 0.08 for the diagnosis of varicocele 104 . Disturbances in the biochemical milieu of infertile testes with clinical varicocele have been observed.…”

“…The literature search found a total of 1106 articles (tumors, n = 584; acute scrotum, n = 193; undescended testes, n = 178; and infertility, n = 151). Ultimately, 83 articles were deemed relevant and used as the literature basis of this review (tumors, n = 50; acute scrotum, n = 6; undescended testes, n = 7; and infertility, n = 20) 6–9,13,24–33,35,43,48–110 . The flow chart of the selection process is shown in Figure 1.…”

“…Recently, scrotal MRI has focused on the evaluation of deranged spermatogenesis. Although reported data are still preliminary and heterogeneous, mainly based on small sample size, various MRI parameters, including ADC, FA, MTR, and testicular metabolites have been described as possible non‐invasive fingerprints of male infertility 91–110 …”

“…MRI may provide useful information regarding the early damage of spermatogenesis in testes with varicocele, possibly helping clinicians to plan appropriate treatment in men who will benefit from varicocele repair 93,94,96,101,103,104,107 . A decrease in ADC has been reported in both testes with varicocele and testes contralateral to varicocele.…”

“…Although reported data are still preliminary and heterogeneous, mainly based on small sample size, various MRI parameters, including ADC, FA, MTR, and testicular metabolites have been described as possible non-invasive fingerprints of male infertility. [91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110] MRI may provide useful information regarding the early damage of spermatogenesis in testes with varicocele, possibly helping clinicians to plan appropriate treatment in men who will benefit from varicocele repair. 93,94,96,101,103,104,107 A decrease in ADC has been reported in both testes with varicocele and testes contralateral to varicocele.…”