Role of Strain Elastography in the Evaluation of Testicular Torsion: An Experimental Study.

Objectives: To evaluate the utility of real-time strain elastography in experimentally induced testicular torsion at different degrees and torsion hours.

Methods: Thirty-one Wistar albino rats were divided into 4 torsion groups by twisting left testes (group I, sham operated; group II, 360°; group III, 720°; and group IV, 1080°). Elastography was applied at the 8th and 24th hours of torsion. Elasticity patterns (pattern 1, soft testis; pattern 2, moderately soft testis; pattern 3, predominantly hard testis; and pattern 4, almost entirely hard testis) and strain ratios were recorded. Histopathologic evaluation was done at the 24th hour. Interobserver agreement was analyzed.

Results: Changes in elastographic patterns and strain ratios among groups II, III, and IV were statistically significant at both hours as determined by both radiologists (P < .01). Elastographic patterns changed from 2 to 3 in groups II and III to 4 in group III between the 8th and 24th hours (P < .05), but in group IV, patterns were reversed, and pattern 1 was observed at both hours. Pathologically severe necrosis (grade 4) was seen in left testes in group IV. In the other groups, pathologic grading in the left testes was as follows: mostly grade 1 in groups I and II and mostly grade 2 in group III. Elastography showed that right testes were affected in group IV, with significant differences in elastographic patterns and strain ratios (P < .01). Interobserver agreement for elastographic patterns in right testes was substantial at the 8th hour (κ = 0.72) and otherwise excellent (κ = 0.81-0.85). Concordance of strain ratios between observers was excellent for right and left testes at the 8th and 24th hours (intraclass correlation coefficients, 0.990 at the 8th hour and 0.987 at the 24th hour).

Conclusions: Our results show that real-time strain elastography can be a complementary method in the evaluation of testicular tissue in testicular torsion and can guide surgeons in their surgical approach.