The Doppler spectral waveform shown in this image of the right testis demonstrates low-resistance, forward- flowing arterial waveforms with continuous diastolic flow - this is characteristic of normal testicular perfusion. The presence of both color Doppler flow and a resistive index (RI) of 0.66 further supports normal testicular arterial circulation.
Key Doppler features of a normal testicular waveform:
* Low-resistance waveform (RI typically 0.5-0.75)
* Continuous diastolic flow
* No reversal of flow or spectral broadening
* Color Doppler confirms uniform intratesticular vascularity
Clinical context:
* Normal testicular flow on Doppler imaging excludes testicular torsion, infarction, or significant inflammation.
* Testicular torsion would show either absent or very high-resistance (reduced or absent diastolic flow) waveform.
* Epididymo-orchitis may show hyperemia with low resistance but often presents with other gray-scale findings like heterogeneous echotexture or scrotal wall thickening.
Differentiation from other options:
* B. Increased resistance: RI >0.75 and reduced or reversed diastolic flow; may indicate impending torsion or ischemia.
* C. Tardus parvus: A slow systolic upstroke and diminished amplitude; indicates proximal arterial stenosis.
* D. Triphasic: Normal waveform in peripheral arteries, such as extremities, not seen in testicular circulation.
References:
Rumack CM, Wilson SR, Charboneau JW, Levine D. Diagnostic Ultrasound. 5th Edition. Elsevier, 2018.
Chapter: Male Pelvis - Testis and Scrotum, pp. 793-800.
AIUM Practice Parameter for the Performance of Scrotal Ultrasound Examinations, 2020.
Radiopaedia.org. Testicular Doppler assessment: https://radiopaedia.org/articles/testicular-doppler-assessment