Images of the scrotum in a patient with right scrotal pain. The two power Doppler images of the right testis (bottom two images) were taken approximately 3 minutes apart.

1. Describe the abnormalities.

2. What congenital anomaly is this patient likely to have?

3. Is it likely that this patient has been symptomatic for less than 24 hours?

4. Explain the difference in appearance of the right testis in the lower left image compared with the lower right image.

ANSWERS – CASE 86

Testicular Torsion

1. The gray-scale view shows testes that are symmetric in echogenicity and normal in appearance. The power Doppler view of the left testis shows normal distribution of flow in multiple intratesticular vessels. The first power Doppler view of the right testis shows no detectable blood flow. The second power Doppler view shows normal intratesticular flow. The first three views are typical of acute right testicular torsion. The lower right image was taken after manual detorsion.

2. The congenital anomaly that predisposes to testicular torsion is a “bell clapper” deformity.

3. The gray-scale appearance of the right testis is normal. This is very good evidence that the testis is still viable. Therefore, it is very likely that the patient has been symptomatic for less than 24 hours.

4. The patient was manually detorsed between the first and second power Doppler views of the right testis. The repeat view of the testis confirmed the success of the maneuver.

References

Cannon ML, Finger MJ, Bulas DI: Case report: Manual testicular detorsion aided by color Doppler ultrasonography. J Ultrasound Med 1995;14:407–409.

Middleton WD, Middleton MA, Dierks M, et al: Sonographic prediction of viability in testicular torsion. J Ultrasound Med 1997;16:23–27.

Middleton WD, Siegel BA, Melson GL, et al: Prospective comparison of color Doppler ultrasonography and testicular scintigraphy in the evaluation of the acute scrotum. Radiology 1990;177:177–181.

Cross-Reference

Ultrasound: THE REQUISITES, 2nd ed, pp 167–171.

Comment

Normally, the testis is anchored to the wall of the scrotum by a broad posterior attachment. This prevents the testis from significant degrees of rotation. The “bell clapper” deformity is a congenital anomaly in which this normal attachment is absent so that the testis is suspended in the scrotal sac via its vascular pedicle, like a clapper in a bell. Patients with a bell clapper deformity are at increased risk for torsion. It is believed that forceful contraction of the cremasteric muscles results in elevation and rotation of the testis and can be the precipitating event in testicular torsion.

Testicular torsion is a condition that most often affects boys in the peripubertal period or men during the young adult years. Patients with persistent torsion requiring medical attention often have had previous episodes of torsion that spontaneously detorse. Typical symptoms include pain and swelling of the scrotum. The pain may radiate into the groin and lower abdomen and is often associated with nausea and vomiting. On physical examination there is often marked tenderness, and the testis may be oriented in a high transverse lie.

With prompt diagnosis and surgical detorsion, there is a good chance that the testis can be salvaged. In fact, if treated within 6 hours of onset, the majority of testes will maintain their viability. If surgery is delayed beyond 24 hours, ischemia causes permanent necrosis of the testis in the large majority of cases. Between 6 and 24 hours after onset, the chance of testicular salvage progressively diminishes.

The diagnosis of torsion is difficult to make based on gray-scale imaging of the testis. In some patients, careful analysis of the inguinal canal will show a twisted spermatic cord. The twisted cord can also be seen as a heterogeneous mass superior to the testis called the torsion knot. It may be difficult to distinguish a torsion knot from an enlarged epididymal head due to epididymitis. In the early stages of torsion, the gray-scale appearance of the testis is normal. In fact, in the setting of torsion, it is possible to predict that the testis is still viable if it has a normal homogeneous echogenicity on gray scale. On the other hand, if the testis appears heterogeneous or hypoechoic on gray scale, then it is almost certainly nonviable. In addition to the changes in the testis, torsion is also frequently associated with a small reactive hydrocele and thickening of the scrotal skin. Unfortunately, all of the gray-scale changes seen in the testis in patients with torsion are nonspecific and can also be seen in patients with orchitis.

The sonographic diagnosis of testicular torsion depends on detecting absent or, in some cases, diminished blood flow to the affected testis with color Doppler. It is important not to mistake color noise with true intratesticular blood flow. Color noise appears as very small, randomly positioned spots of red and blue color assignment that have no pulsed Doppler signal. True vessels appear as larger, better formed areas of color assignment that can usually be elongated by various degrees of transducer rotation. In addition, true vessels should have a detectable pulsed Doppler signal. With prolonged torsion, an inflammatory reaction develops in the scrotal wall, and hyperemia can be detected in the tissues around the testis.

CASE 87

Pulsed Doppler waveforms of the left vertebral artery. Note that both waveforms are inverted, with negative frequency shifts displayed above the baseline.

1. What is the cause of this abnormality?

2. What was done to cause the difference in the two waveforms?

3. Is color Doppler adequate to make the diagnosis or is pulsed Doppler also required?

4. Is this abnormality more common on the right or on the left?