The Study On Acute Experimental Incomplete Testicular Torsion By Ultrasonography

Objective:To explore the application value of ultrasoundgraphy and contrast-enhanced ultrasoundgraphy (CEUS) in the diagnosis of acute experimental incomplete testicular torsion.Methods:Eight healthy dogs were surgically modeled to twist unilateral acute partial testicular torsion randomly. Seven of them were made incomplete torsion models, and the last dog was made complete model. Using the twisted testes as model group and the healthy testes as control group, by two-dimensional ultrasoundgraphy (2DU), internal echoes and volume of testicular and spermatic cord diameter were measured before torsion, immediately after torsion,2nd,4th and 6th hour after torsion. By pulsed wave Doppler (PWD), the peak systole velocity(PSV) and resistance index(RI) of intratesticular artery, capsular artery and arteria spermatica interna were measured before torsion,2nd,4th and 6th hour after torsion. The blood flow of the trail testis were observed by color Doppler flow imaging (CDFI) and power Doppler imaging (PDI), and compared with their positive rate. Every dog was undergone CEUS immediately or/and 6th hour after torsion and compared its positive rate with CDFI and PDI at the same time. Testes were examined by pathology after the experiment.Results:The torsional segments of spermatic cord diameter in 2nd,4th and 6th hour were 7.88±1.47mm,8.76±0.84mm and 9.44±0.81mm respectively, and were thicker than contralateral intact one (5.49±0.42 mm) and the spermatic cord diameter before torsion(5.79±0.72 mm)(P<0.05).The PSV and RI of capsular artery and intratesticular artery were decreased gradually with the extension of torsional time (P<0.05). The PSV and RI of superior, torsional and inferior segments of arteria spermatica interna varied greatly and showed no strong regularity and no statistical significance(P> 0.05). The total positive rate of CDFI and PDI in partial testicular torsion with different time were24/49,27/49 respectively. There was no statistical significance between them (P>0.05). after torsion, or/and 6 hours after torsion, and the time-intensity curves were analysed. Arriving time(AT), time to peak(TTP) of contrast materials of bilateral testes were coincidence, and peak intensity(PI), area under the curve(AUC) of bilateral testes were identical basically before torsion. Cases of incomplete testicular torsion were delayed perfusion. AT, TTP were prolonged, and PI, AUC were decreased than contralateral testes(P<0.05). The total positive rate of CDFI, PDI and CEUS in partial testicular torsion with different time were 6/10,6/10,10/10 respectively. There was statistical significance among them (P<0.05) Non-perfusion was observed in the complete testicular torsion all the time. The results of testes by pathology showed no significant changes or just showed interstitial slight congestion and hydropsia.Conclusions:1. The thickening of torsional segments of spermatic cords plays an important role in diagnosing acute partial testicular torsion.2. CDFI, PDI can be adopted as the methods to diagnose acute incomplete testicular torsion. The positive rate of the two technologies are corresponding.3. The PSV and RI of superior, torsional and inferior segments of arteria spermatica interna were not reliable to judge acute experimental incomplete testicular torsion. The decreasing of the PSV and RI of capsular artery and intratesticular artery, especially RI, have referential value.4. CEUS has very high application value in the diagnosis of acute experimental incomplete testicular torsion. CEUS are superior to CDFI and PDI.