scrotal scintigraphy
Scrotal scintigraphy is a radio-isotope examination of the scrotal contents, primarily in patients presenting with scrotal pain.
Indications
Although, ultrasound remains the mainstay of scrotal imaging, scintigraphy can be used where the diagnosis is unclear, since ultrasound appearances for scrotal pathologies often overlap.
Indications include:
- to evaluate for emergent causes of acute or subacute scrotal pain
- to differentiate suspected testicular torsion from epididymo-orchitis
Contraindications
There are no hard contraindications, but radiation dose should be considered, particularly in young patients whose presentation warrants surgical exploration regardless. Inappropriate reasons for scrotal scintigraphy include:
- evaluating cryptorchidism
- suspected chronic testicular inflammation
- evaluating for testicular tumors
Technique
Technetium-99m pertechnetate is the most commonly used radiopharmaceutical, though DTPA may be used as well.
The patient is placed under the gamma camera supine with legs slightly adducted. The scrotum may be suspended on a sling or elevated using towels. The radio-isotope is then delivered intravenously as a bolus. Images are then acquired in the perfusion phase during the first minute. Further images are taken at a delay of up to 10 minutes.
The symptomatic side should be indicated on images.
Interpretation
Sensitivity and specificity have both been reported at over 90% for testicular torsion .
Testicular torsion
- large central photopenic area
- surrounding hyperemic rim may be seen in missed torsion
Epididymo-orchitis
- increased perfusion
- enlarged testicular outline
- increased tracer uptake