Pediatric Radiology | 2021
Ultrasound for malrotation and volvulus: has the time come?
Abstract
There is probably no congenital condition as horrid as intestinal malrotation. A seemingly normal child can present acutely, and, even if expediently diagnosed and operated on, might in a short time die or be left with severe lifelong debility from short gut syndrome. Getting the diagnosis quickly and correct is paramount. A decade ago, we published two papers by Dr. David Yousefzedah on US for malrotation [1, 2]. In Dr. Yousefzedah’s hands (key point) and limiting the study to newborns, US performed well for differentiating normal from malrotation [2]. Dr. Yousefzedah looked for the third portion of the duodenum crossing midline posterior to the superior mesenteric artery. He demonstrated a retromesenteric course of the third portion of the duodenum in 33 of 33 newborns [2]. The papers received much attention. Many pediatric radiologists and groups have subsequently tried US for malrotation. Informally, we did in our practice. We failed. Two of my colleagues, both of whom I consider to be exceptionally talented with a transducer in hand, tried to emulate Dr. Yousefzedah’s techniques but stated that they could not confidently exclude malrotation. If these twomaster sonographers could not, how could the rest of us? Some practices, mostly outside the United States, have further pursued US for the diagnosis of malrotation [3–12]. Some have achieved substantial success. Most notable in the United States has been the group at Phoenix Children’s Hospital [12]. In their hands, US was diagnostic in 92% of 195 patients, and, when diagnostic, both the negative and positive predictive values were 100% [12]. Other groups have published as well. A key, it would seem, for making the diagnosis of malrotation — or more critically (because this would stop further workup or treatment), for excluding the diagnosis of malrotation — is to be absolutely certain that you are viewing the duodenum and not misidentifying another section of bowel as the retromesenteric portion of the duodenum. It is thus paramount to follow the bowel loop from the stomach and pylorus through its course behind the superior mesenteric artery. Regardless of whether a practice chooses to use US to make the diagnosis of malrotation and volvulus, it is important to be cognizant of its appearance on US because the diagnosis might be present when not expected— a vomiting child from the emergency room; a child with chronic vomiting, abdominal pain or failure to thrive; a neonate with a distended abdomen who is clinically suspected of having necrotizing enterocolitis. In all of these instances, and others, one might encounter a malrotation with volvulus. If you don’t know what a volvulus looks like, you might miss it or misinterpret it. If you don’t look for a volvulus, you are likely to miss it. In this issue of Pediatric Radiology, a group of authors from Texas Children’s Hospital shares their experience with US for malrotation with volvulus. They have illustrated the US findings in an excellent pictorial essay [13]. They delineate their buy-in, training and ramp-up process in an accompanying commentary [14]. Texas Children’s Hospital is the largest children’s hospital in North America. It is very well resourced. The radiology group has around-the-clock in-house attending coverage in its main hospital. All US exams are performed by dedicated pediatric sonographers. The group does cover two smaller communitybased children’s hospitals, which are included in this initiative, for which the US exams are interpreted remotely by in-house pediatric body radiologists at the main hospital. Based on the information provided, how are they doing? The results are good. But are they good enough? The authors noted that “Overall, ultrasound prospectively reported malrotation with midgut volvulus in 13 of 16 (81%) [patients]” [14]. Even one missed volvulus needs be concerning. I, however, applaud the Texas Children’s group for their willingness to test the waters, for their diligence in implementation and for carrying this through with relative success. As evidenced by this work at Texas Children’s Hospital, one must know the sonographic findings of volvulus and to * Peter J. Strouse [email protected]