What follows is the Sonographic Protocol For Suspected Testicular Torsion from Resource (1) below, Testicular torsion with preserved flow: key sonographic features and value-added approach to diagnosis [PubMed Abstract] [Full Text HTML] [Full Text PDF]. Pediatr Radiol. 2018 May;48(5):735-744. doi: 10.1007/s00247-018-4093-0. Epub 2018 Feb 21.
[Note to myself: This post is just excerpts amounting to a very brief summary and when I want to review the topic in depth I need to reread the whole article.]
The HTML version of the above article has eleven videos that you can download and play as you go through the article. They are in the electronic supplementary material just after the conclusion and before the references.
[Note to myself: I’ve downloaded all the avi files to my computer in the folder “testicular torsion videos from the us article. The avi files will not play in the Windows Media Player but will play in another of my video players.]
And after the Sonographic Protocol I’ve made some excerpts from the article for these my medical study notes [this post].
And here are some excerpts from the article:
Testicular sonography has contributed greatly to the preoperative diagnosis of testicular torsion in the pediatric patient and is the mainstay for evaluation of acute scrotal pain. Despite its high sensitivity and specificity, both false-negative and false-positive findings occur. Presence of documented Doppler flow within the testis might be a dissuading factor for surgical exploration with resultant testicular loss in the false-negative cases. Our goal is to illustrate key sonographic features in the spectrum of testicular torsion with preserved testicular flow, and to describe how to differentiate testicular torsion from epididymitis in order to avoid the under-diagnosis of testicular torsion. We simplify the anatomy of the bell clapper testis. We also describe our sonographic protocol for testicular torsion and share valuable tips from our approach to challenging cases.
Recent investigators have emphasized the concept of intermittent and partial testicular torsion, which can be difficult to diagnose with sonography because these cases have either subtle decreased flow or flow that appears to be symmetrical with the contralateral testis, and symptoms can wax and wane . Such cases might present diagnostic dilemmas for both the pediatric radiologist and urologist. Testicular torsion is not an all-or-none phenomenon and can be of complete, partial or intermittent types. The incidence of each type of torsion in isolation is unknown. In a study in which all children with symptoms of acute scrotum underwent surgical revision, torsion of the appendix testis was the most common pathology (57%), followed by torsion of the spermatic cord (27%) and much less commonly epididymitis (11%) .
Complete torsion occurs when the testis twists 360° or greater, usually leading to absence of intratesticular flow on color Doppler exam; however sometimes the flow is preserved or decreased. Intermittent torsion is defined as sudden onset of unilateral testicular pain of short duration with spontaneous resolution. In partial or incomplete torsion, the degree of spermatic cord twist is less than 360°, allowing for some residual perfusion to the testis. However there is no spontaneous resolution of pain .
Testicular torsion has been reported to have a bimodal distribution, an initial peak in the first year of age where the torsion is of extravaginal type, and a second surge in adolescence where intravaginal torsion is common. Cases of intravaginal torsion with preserved flow and their critical sonographic findings are described in this review. Preserved flow indicates these cases did not have completely absent flow (which is typically straightforward and diagnostic for testicular torsion) on color Doppler exam. Instead, the affected testis had either decreased or symmetrical preserved flow compared to the contralateral unaffected side, sometimes even increased flow . In many of our cases, it was extremely difficult to decide whether the flow was truly symmetrical to the contralateral side or was subtly decreased. Of all the cases with preserved flow, decreased flow in the affected testis was more commonly observed than symmetrical or increased flow. The patient age in our cases ranged from 3 years to 19 years, the majority being 12 years and older. While studying some of our youngest patients (3–6 years), we noted that they all presented with abdominal pain, nausea and vomiting, and received the typical workup for pain including ultrasound examination to rule out appendicitis. The nonspecific symptoms resulted in a delayed diagnosis. It is important to remember that intravaginal torsion can occur even in such young patients, though less frequently compared to adolescents, and when presentation is right-sided it can mimic appendicitis. A clinical examination of the scrotum is recommended in all boys with right lower quadrant pain and a low threshold for a scrotal ultrasonography.
Anatomy of the bell clapper testis
The bell clapper anomaly has been defined as an abnormally high attachment of the tunica vaginalis parietal lamina to the spermatic cord such that the tunica vaginalis completely encircles the epididymis, the distal unattached spermatic cord and the testis rather than attaching to the posterolateral aspect of the testis (Fig. 1) .
Sonographic Protocol For Suspected Testicular Torsion
Our sonographic protocol for suspected testicular torsion is described (Table 1 above). Asking the child which side hurts before starting is recommended so that the color Doppler parameters can be optimized in the normal testis, and then the affected side can be interrogated using the same settings. Phrases such as “slightly increased or decreased flow” and “symmetrical or asymmetrical flow” are descriptive, and using them to describe the testicular vascularity is encouraged because they can be extremely helpful in depicting the parenchymal flow in the report. In a normal testis, color flow is seen as a mix of red and blue long linear robust channels representing intratesticular arterial and venous flow. Decreased flow is usually manifested as scattered blips of flow in vessels that appear rather diminutive and resemble dots and dashes. Increased flow is easier to appreciate by the increased number and fullness of vessels. If no appreciable difference can be detected by the viewer, the flow is considered symmetrical. The decision about color Doppler flow is subjective but is best accomplished by looking at both testes simultaneously in the transverse plane, in real time. We recommend obtaining a midline transverse color static cine clip of both testes side-by-side to show real-time intrinsic flow at the beginning of the exam when the testes have not yet been manipulated by the transducer.
Swollen epididymis and testis with testicular flow that is only minimally decreased, normal, or increased in boys with incomplete or intermittent testicular torsion can mimic epididymo-orchitis. The most common cause of acute scrotal pain in children is torsion of appendix testis, which can also mimic epididymo-orchitis. Therefore it is important to evaluate for the presence of avascular nodule that might represent the torsed appendage (Fig. (Fig.8;8; videos 9, 10 and 11, online supplementary material). Any time a child presents with acute scrotal pain, and findings resembling epididymitis without findings of torsed appendage, testicular torsion should be excluded. Suspicion of intermittent or incomplete testicular torsion should be raised in a child with a history of recurrent epididymitis or epididymo-orchitis, or abrupt pain that resolved or decreased at the time of diagnosis.
(1) Testicular torsion with preserved flow: key sonographic features and value-added approach to diagnosis [PubMed Abstract] [Full Text HTML] [Full Text PDF]. Pediatr Radiol. 2018 May;48(5):735-744. doi: 10.1007/s00247-018-4093-0. Epub 2018 Feb 21.
At the very end of the HTML online full text version of the article, there are links to 11 avi videos that you can download and play as you review the relevant portion of the article.