Uroradiology & genital male imagingCase Type
Bineeta Singh Parihar, Pragati Gakher, Usha Jaipal, Dinesh Gautam, Kuldeep Kumar MendirattaPatient
24 years, male
A 24 years old male presented with complaint of painful priapism for 5 days after a motor vehicle accident leading to straddle injury. There was no significant prior medical or surgical history. His vitals were stable and blood cell counts were normal.
On grayscale ultrasonography (fig 1) of patient, there were hypoechoic lobulated lesions one each in bilateral corpora cavernosa at base of penile shaft with dilated cystic spaces likely representing dilated sinusoids. Color Doppler (fig 2 a and b) revealed high velocity to and fro flow pattern in the lobulated lesions and showed communication with dilated cavernosal arteries. Penile fascia, corpus spongiosum and testis were normal.
On CT angiography (fig 4) of pelvis, there were bulky bilateral corpora cavernosa with active extravasation of contrast into pseudoaneurysms from cavernosal branches of bilateral internal pudendal arteries.
After a failed attempt of conservative treatment by compression, angiographic embolization was planned.
Digital subtraction angiography with selective angiogram of internal pudendal arteries demonstrated filling of bilateral pseudoaneurysms supplied by cavernosal branches. Right side pseudoaneurysm was larger in size than the left side. Under DSA guidance (fig 5 showing right-sided pseudoaneurysm), coil embolization of right penile cavernosal artery was done. Post embolization angiogram showed non-opacification of culprit artery.
Prolonged penile erection not associated with sexual desire is called priapism.  There are two types of priapism- 1. Low flow (ischemic) - most common type, resulting from venous outflow obstruction, and 2. High flow (non-ischemic) - resulting from uncontrolled penile arterial inflow into corpora cavernosa. 
High flow priapism is usually painless, presenting after trauma with incompletely erected phallus.
Whereas low flow priapism is considered as an emergency with rigid painful priapism and can cause irreversible ischemic changes, leading to permanent erectile dysfunction if management is delayed. 
The role of imaging in the management of low flow priapism is limited as it has acute presentation and rapid relief of ischemic state by corporal blood aspiration and administration of phenylephrine or surgical stent is needed. 
On the other hand, in high flow priapism, selective embolization of culprit pseudoaneurysm or arterocavernosal fistula by use of embolization agents like microcoils, gelatin sclerosent and glue can be attempted after imaging guidance by colour doppler and angiography.  On grayscale ultrasound, there is irregular hypoechoic lobulated area adjacent the tear in cavernosal artery in background of echogenic cavernosal tissue.  On colour doppler, extravasation of blood from cavernosal artery is seen with high velocity to and fro flow pattern in pseudoaneurysm.
CT angiography shows the relationship of the pseudoaneurysm with the artery of origin, and the route for angiographic embolization can be planned based on 3D anatomy of vessels depicted by angiography. 
Take home message
Bilateral cavernosal artery pseudoaneurysm as a cause of high flow priapism is quite rare. However prompt imaging should be done for detection of these lesions for proper management by selective embolization to relieve symptoms of the patient and to prevent further catastrophic sequel.
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