Pulse-Inversion US Imaging of Testicular Ischemia: Quantitative and Qualitative Analyses in a Rabbit Model

Purpose: To quantitatively and qualitatively assess perfusion with pulse-inversion (PI) ultrasonography (US) in rabbit model of acute testicular ischemia.

Materials and Methods: Institutional animal care committee approval was obtained. After 35 rabbits underwent unilateral spermatic cord occlusion, testicular Doppler US and contrast material–enhanced PI imaging were performed. Enhancement data yielded perfusion measurements including mean value during the first 10 seconds, mean value over entire recorded replenishment curve, and curve slope during the first 5 seconds. Calculated perfusion ratios were compared with radiolabeled microsphere–derived perfusion ratios. Two readers assessed testicular perfusion as none, possible, or definite and relative perfusion as greater to the right testis than to the left, greater to the left testis than to the right, or as equal to both testes. With κ statistics, interobserver agreement for all imaging methods was determined. Association between qualitative perfusion categories and radiolabeled microsphere–based perfusion measurements was assessed. Quantitative and qualitative determinations of relative perfusion were compared with radiolabeled microsphere–based measurements.

Results: Correlations between calculated and radiolabeled microsphere–based perfusion ratios were determined (r = 0.49–0.64). Interobserver agreement for presence of perfusion was excellent (κ = 0.76), and that for relative perfusion assessment was good (κ = 0.55). Neither κ value varied significantly with imaging method. The percentage of times a testis classified as having definite perfusion had greater perfusion as measured with radiolabeled microspheres than a testis classified as having no perfusion or possible perfusion was higher with PI imaging than with Doppler US (85%–98% vs 72%–89%). Identification of the testis with less perfusion was better with quantitative methods than with qualitative assessment of images by the readers (75%–79% vs 34%–60%, P < .004).

Conclusion: PI imaging, compared with conventional Doppler US methods, provides superior assessment of perfusion in the setting of acute testicular ischemia.

© RSNA, 2006

References

  • 1 Williamson RC. Torsion of the testis and allied conditions. Br J Surg 1976; 63: 465–476.
  • 2 Scorer CG, Farrington GH. Torsion of the testis. In: Congenital deformities of the testis and epididymis. London, England: Butterworths, 1971; 118–135.
  • 3 Cass AS, Cass BP, Veeraraghavan K. Immediate exploration of the unilateral acute scrotum in young male subjects. J Urol 1980;124:829–832.
  • 4 Lerner RM, Mevorach RA, Hulbert WC, Rabinowitz R. Color Doppler US in the evaluation of acute scrotal disease. Radiology 1990;176:355–358.
  • 5 Burks DD, Markey BJ, Burkhard TK, Balsara ZN, Haluszka MM, Canning DA. Suspected testicular torsion and ischemia: evaluation with color Doppler sonography. Radiology 1990;175:815–821.
  • 6 Dogra VS, Gottlieb RH, Oka M, Rubens DJ. Sonography of the scrotum. Radiology 2003;227:18–36.
  • 7 Middleton WD, Siegel BA, Melson GL, Yates CK, Andriole GL. Acute scrotal disorders: prospective comparison of color Doppler US and testicular scintigraphy. Radiology 1990;177:177–181.
  • 8 Paltiel HJ, Rupich RC, Babcock DS. Maturational changes in arterial impedance of the normal testis in boys: Doppler sonographic study. AJR Am J Roentgenol 1994;163:1189–1193.
  • 9 Paltiel HJ, Connolly LP, Atala A, Paltiel AD, Zurakowski D, Treves ST. Acute scrotal symptoms in boys with an indeterminate clinical presentation: comparison of color Doppler sonography and scintigraphy. Radiology 1998;207:223–231.
  • 10 Kalfa N, Veyrac C, Baud C, Couture A, Averous M, Galifer RB. Ultrasonography of the spermatic cord in children with testicular torsion: impact on the surgical strategy. J Urol 2004;172:1692–1695.
  • 11 Hormann M, Balassy C, Philipp MO, Pumberger W. Imaging of the scrotum in children. Eur Radiol 2004;14:974–983.
  • 12 Nussbaum Blask AR, Bulas D, Shalaby-Rana E, Rushton G, Shao C, Majd M. Color Doppler sonography and scintigraphy of the testis: a prospective, comparative analysis in children with acute scrotal pain. Pediatr Emerg Care 2002;18:67–71.
  • 13 Grant EG. Sonographic contrast agents in vascular imaging. Semin Ultrasound CT MR 2001;22:25–41.
  • 14 Hope Simpson D, Chin CT, Burns PN. Pulse inversion Doppler: a new method for detecting nonlinear echoes from microbubble contrast agents. IEEE Trans Ultrason Ferroelectr Freq Control 1999;46:372–382.
  • 15 Bauer A, Hauff P, Lazenby J, et al. Wideband harmonic imaging: a novel contrast ultrasound imaging technique. Eur Radiol 1999;9(suppl 3):S364–S367.
  • 16 Harvey CJ, Blomley MJ, Eckersley RJ, et al. Hepatic malignancies: improved detection with pulse-inversion US in late phase of enhancement with SHU 508A—early experience. Radiology 2000;216:903–908.
  • 17 Halpern EJ, Rosenberg M, Gomella LG. Prostate cancer: contrast-enhanced US for detection. Radiology 2001;219:219–225.
  • 18 Burns PN, Wilson SR, Hope Simpson D. Pulse inversion imaging of liver blood flow: improved method for characterizing focal masses with microbubble contrast. Invest Radiol 2000;35:58–71.
  • 19 Postert T, Federlein J, Rose J, Przuntek H, Weber S, Buttner T. Ultrasonic assessment of physiological echo-contrast agent distribution in brain parenchyma with transient response second harmonic imaging. J Neuroimaging 2001;11:18–24.
  • 20 Federlein J, Postert T, Meves S, Weber S, Przuntek H, Buttner T. Ultrasonic evaluation of pathological brain perfusion in acute stroke using second harmonic imaging. J Neurol Neurosurg Psychiatry 2000;69:616–622.
  • 21 Goldberg BB, Liu JB, Forsberg F. Ultrasound contrast agents: a review. Ultrasound Med Biol 1994;20:319–333.
  • 22 Burns PN. Harmonic imaging with ultrasound contrast agents. Clin Radiol 1996;51(suppl 1):50–55.
  • 23 Frush DP, Babcock DS, Lewis AG, et al. Comparison of color Doppler sonography and radionuclide imaging in different degrees of torsion in rabbit testes. Acad Radiol 1995;2:945–951.
  • 24 O'Hara SM, Frush DP, Babcock DS, et al. Doppler contrast sonography for detecting reduced perfusion in experimental ischemia of prepubertal rabbit testes. Acad Radiol 1996;3:319–324.
  • 25 Coley BD, Frush DP, Babcock DS, et al. Acute testicular torsion: comparison of unenhanced and contrast-enhanced power Doppler US, color Doppler US, and radionuclide imaging. Radiology 1996;199:441–446.
  • 26 Wei K, Skyba DM, Firschke C, Jayaweera AR, Lindner JR, Kaul S. Interactions between microbubbles and ultrasound: in vitro and in vivo observations. J Am Coll Cardiol 1997;29:1081–1088.
  • 27 Chomas JE, Dayton P, Allen J, Morgan K, Ferrara K. Mechanisms of contrast agent destruction. IEEE Trans Ultrason Ferroelectr Freq Control 2001;48:232–248.
  • 28 Sirlin CB, Girard MS, Baker KG, Steinbach GC, Deiranieh LH, Mattrey RF. Effect of acquisition rate on liver and portal vein enhancement with microbubble contrast. Ultrasound Med Biol 1999;25:331–338.
  • 29 Wei K, Jayaweera AR, Firoozan S, Linka A, Skyba DM, Kaul S. Quantification of myocardial blood flow with ultrasound-induced destruction of microbubbles administered as a constant venous infusion. Circulation 1998;97:473–483.
  • 30 Cosgrove D, Eckersley R, Blomley M, Harvey C. Quantification of blood flow. Eur Radiol 2001;11:1338–1344.
  • 31 Kleinbaum DG, Kupper LL, Muller KE, Nizam A. Applied regression analysis and other multivariable methods. 3rd ed. Pacific Grove, Calif: Duxbury, 1998; 99–100.
  • 32 Diggle PJ, Heagerty PJ, Liang KY, Zeger SL. Analysis of longitudinal data. 2nd ed. Oxford, England: Oxford University Press, 2002; 70–80.
  • 33 Hanley JA, McNeil BJ. The meaning and use of the area under a receiver operating characteristic (ROC) curve. Radiology 1982;143:29–36.
  • 34 Efron B, Tibshirani RJ. An introduction to the bootstrap. London, England: Chapman & Hall, 1993.
  • 35 Fleiss JL, Levin B, Paik MC. Statistical methods for rates and proportions. 3rd ed. New York, NY: Wiley, 2003.
  • 36 Holm S. A simple sequentially rejective multiple test procedure. Scand J Stat 1979;6:65–70.
  • 37 Becher H, Burns PN. Methods for quantitative analysis, chap 4. In: Handbook of contrast echocardiography: LV function and myocardial perfusion. Berlin, Germany: Springer, 2000; 153–171.
  • 38 Heymann MA, Payne BD, Hoffman JI, Rudolph AM. Blood flow measurements with radionuclide-labeled particles. Prog Cardiovasc Dis 1977;20:55–79.
  • 39 Lucidarme O, Franchi-Abella S, Correas JM, Bridal SL, Kurtisovski E, Berger G. Blood flow quantification with contrast-enhanced US: “entrance in the section” phenomenon—phantom and rabbit study. Radiology 2003;228:473–479.
  • 40 Schlosser T, Pohl C, Veltmann C, et al. Feasibility of the flash-replenishment concept in renal tissue: which parameters affect the assessment of the contrast replenishment? Ultrasound Med Biol 2001;27:937–944.
  • 41 Potdevin TC, Fowlkes JB, Moskalik AP, Carson PL. Analysis of curve refill shape in ultrasound contrast agent studies. Med Phys 2004;31:623–632.
  • 42 Villanueva FS, Abraham JA, Schreiner GF, et al. Myocardial contrast echocardiography can be used to assess the microvascular response to vascular endothelial growth factor-121. Circulation 2002;105:759–765.
  • 43 Linka AZ, Sklenar J, Wei K, Jayaweera AR, Skyba DM, Kaul S. Assessment of transmural distribution of myocardial perfusion with contrast echocardiography. Circulation 1998;98:1912–1920.
  • 44 Rim SJ, Leong-Poi H, Lindner JR, et al. Quantification of cerebral perfusion with “real-time” contrast-enhanced ultrasound. Circulation 2001;104:2582–2587.
  • 45 Seidel G, Meyer K. Harmonic imaging: a new method for the sonographic assessment of cerebral perfusion. Eur J Ultrasound 2001;14:103–113.

Article History

Published in print: June 2006