Utility of Real-Time Shear Wave Elastography in the Assessment of Testicular Torsion

Abstract

Real-time shear-wave elastography (SWE) is a newly developed method which can obtain the stiffness of tissues and organs based on tracking of shear wave propagation through a structure. Several studies have demonstrated its potential in the differentiation between diseased and normal tissue in clinical practices, however the applicability to testicular disease has not been well elucidated. We investigated the feasibility and reproducibility of SWE in the detection of testicular torsion. This prospective study comprised 15 patients with complete testicular torsion. Results obtained from SWE along with conventional gray-scale and color Doppler sonography and post-operative pathology were compared. The results revealed that (i) the size of injured testis was increased and the twisted testis parenchyma was heterogeneous. The blood flow signals in injured testis were barely visible or absent; (ii) The Young's modulus, including Emean, Emax, Emin and SD values in the border area of torsional testis were higher than those of normal testis (Emean, 78.07±9.01 kPa vs 22.0±5.10 kPa; Emax, 94.07±6.53 kPa vs 27.87±5.78 kPa; Emin, 60.73±7.84 kPa vs 18.90±4.39 kPa; SD, 7.67±0.60 kPa vs 2.30±0.36 kPa, [P<0.05]); The Emax and SD values in the central area of the torsional testis were higher than the corresponding area of the normal testis (Emax, 8.23±0.30 kPa vs 3.97±0.95 kPa; SD, 1.5±0.26 kPa vs 0.67±0.35 kPa,[P<0.05]) and Emin values was lower than those of normal testicles (0.93±0.51 kPa vs 1.6±0.36 kPa; [P<0.05]); (iii) The Young's modulus measurement between two physicians showed good agreement. The pathological findings were accordance with SWE measurement. SWE is a non-invasive, convenient and high reproducible method and may serve as an important alternative tool in the diagnosis and monitoring the progression of the acute scrotums, in additional to conventional Doppler sonography.

Fig 1. Gray-scale sonography and color Doppler sonography of twisted and normal testis.

A: homogeneous testicular essence in the normal testicle. B: well blood flow signal inside in the normal testicle. C: swollen twisted testicle and heterogeneous echo inside. D: absent blood flow signal in the twisted testicle.

Fig 2. The SWE imaging of twisted and normal testicles.

A: the SWE imaging of twisted testicles; B: the SWE imaging of normal testicles.

Fig 3. The Emean, Emax, Emin and SD comparison in the border area of torsional and normal testis.

Compared with the Emean, Emax, Emin and SD values in the border area of torsional testis, *P<0.05.

Fig 4. The Emean, Emax, Emin and SD comparison in the central area of torsional and normal testis.

Compared with the Emean, Emax, Emin and SD values in the central area of normal testis, *P<0.05.

Fig 5. The Emean, Emax, Emin and SD comparison in the central area of torsional testis measured by two senior sonographers.

Fig 6. The pathological result of torsional testis.

6A-6B: the orchiectomy specimens showed that the size of torsional testis increased and the testis infarction appeared dark red or jet black; 6C-6E: HE staining showed that the lobular gap cavities of infarct testis was filled with diffuse hemorrhage and sporadic died interstitial cells, a large number of spermatogonia, extensive coagulation necrosis of spermatocytes in seminiferous tubules, interstitial hyperplasia and lymphocyte infiltration.