Anticlockwise swirl of mesenteric vessels: a normal CT appearance, retrospective analysis of 200 pediatric patients.
OBJECTIVE
The counterclockwise rotation of the SMV on SMA is a normal and non-specific finding, which results in an incomplete swirl formation on CT scans. However, it has a potential to be misinterpreted as 'midgut volvulus' resulting in serious clinical implications. The study was done to determine the frequency and degree of counterclockwise rotation of the SMV on SMA on CT in normal otherwise asymptomatic pediatric patients undergoing CT scan.


METHODS
In this IRB approved study, we retrospectively analyzed abdominal CT scan examinations of 200 consecutive pediatric patients (age range of 11 days to 18 years), which were performed for different clinical indications over a period of 10 months. They were evaluated for the absence or presence and degree of counterclockwise rotation of the mesenteric vessels.


RESULTS
Of the 200 patients, 128 (64%) patients showed no clockwise or anticlockwise rotation of mesenteric vessels. Counterclockwise rotation of SMV on SMA was seen in 72 (36%) patients. Further, the degree of rotation of vessels was also calculated, based on the criteria proposed by the authors.


CONCLUSIONS
The counterclockwise rotation of SMV on SMA gives an appearance of mesenteric whirlpool in otherwise normal mesenteric vessels and can be misinterpreted as midgut volvulus. It is a normal CT appearance and is due to a variation in branching pattern of mesenteric vessels. Awareness of this normal branching pattern of mesenteric vessels is important to avoid an inadvertent laparotomy.
Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: sodhiks@gmail.com.
Kushaljit S
KS
Sodhi
Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: anmol_bhatia26@yahoo.co.in.
Anmol
A
Bhatia
Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: fatakshay@yahoo.com.
Akshay K
AK
Saxena
Department of Pediatric Surgery, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: klnrao@hotmail.com.
Katragadda L N
KL
Rao
Department of Pediatric Surgery, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: menonprema@hotmail.com.
Prema
P
Menon
Department of Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Sector-12, Chandigarh 160012, India. Electronic address: khandelwaln@hotmail.com.
Niranjan
N
Khandelwal
D000293:Adolescent; D000792:Angiography / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004065:Digestive System Abnormalities / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D045822:Intestinal Volvulus / Q000000981:diagnostic imaging*; D008297:Male; D008638:Mesenteric Arteries / Q000000981:diagnostic imaging*; D008642:Mesenteric Veins / Q000000981:diagnostic imaging*; D012016:Reference Values; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
Anticlockwise; Children; Computed tomography; Malrotation; Mesenteric; Swirl; Vessels