Source: Perez-Rossello JM, Connoly S, Newton A, et al. Wholebody MRI in suspected infant abuse. AJR. 2010; 195(3): 744– 750; doi: 10.2214/AJR.09.3364Investigators from Children’s Hospital of Boston assessed the utility of whole-body MRI as compared to skeletal survey (SS) for finding skeletal and soft tissue injuries in infants with suspected physical abuse. They retrospectively analyzed imaging studies performed in 21 infants who met entry criteria from March 2003 to October 2005 and who underwent whole-body 1.5 Tesla magnetic resonance imaging (MR) within 5 days of the SS. Sixteen infants also had a follow-up SS; the combined findings of both surveys were referred to as the “summary skeletal survey.”Fifty-two body areas were analyzed on the MR and SS. Each examination type was reviewed for mean total number of injuries. Coronal and sagittal MR images were obtained using STIR sequences. Slice thicknesses were 3 to 5 mm. SS were performed using departmental protocol and the recommendations of the American College of Radiology. A pediatric radiologist monitored the SS studies and requested additional views, if necessary. MR images were reviewed independently by two board-certified pediatric radiologists who were aware of the history but were blinded to the SS findings. Bones, soft tissues, and solid organs were studied for abnormality. A third radiologist, blinded to the MR findings, studied the SS radiographs. The cervical spine was not evaluated as the whole-body examination began at the shoulder.Overall concordance rate was 95% for pre-MR SS versus follow-up SS, 87% for initial SS versus MR, and 89% for summary SS versus MR. There was no statistical difference between the average of 4.7 areas of abnormality seen on MR and the 5.4 fractures seen on the SS. Of the total of 167 fractures in the 21 children, 40.7% were seen by SS only, 31.7% by MR alone and 27.5% by both techniques. MR had a high specificity (95%) but a low sensitivity (40%). Radiography (24 of 37) was superior to MR (2 of 37) in finding metaphyseal corner fractures. MR sensitivity to this classic finding in child abuse was only 31%. MR was superior to SS for soft tissue injuries. Soft tissue injuries included 84 instances of muscle edema and 54 of subcutaneous edema, as well as 15 joint effusions, 12 pleural effusions, 3 intra-abdominal free fluid, 1 liver laceration, and 1 ligamentous injury of the spine.The authors emphasize the limited ability of MR to detect metaphyseal corner fractures and rib fractures, the most specific fractures for nonaccidental trauma and responsible for 90% of noncranial skeletal injuries in infant abuse fatalities. The authors conclude that MR cannot replace, but may complement, the SS.Dr Cohen has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.The best imaging for the infant with suspected physical abuse continues to be “old-fashioned” skeletal radiographs. Since Caffey’s landmark article1 in 1946 describing the imaging findings of the battered child, consistently achieving the goal of early diagnosis has been a major challenge. The medical, social, and legal consequences of missed diagnosis are of obvious major importance. The current study showed that 7 of 21 cases of child abuse would not have been diagnosed by MR alone. The absence of ionizing radiation makes MR an appealing imaging option. However, despite the accompanying radiation exposure, the pediatrician should not be dissuaded from ordering SS, which provide far superior identification of classic child abuse findings like metaphyseal corner fractures and rib fractures and which provide better information on the ages of the injuries.2 This study also demonstrates the superior ability of MR to pick up soft tissue injuries which can obscure fractures on SS and require follow-up. Scintigraphy may play a complementary role.Notably, some fractures were not identified on either study. Clinicians should use their judgment based on history, physical, and radiologic findings to identify and manage possible cases of physical abuse. When child abuse is suspected, an open dialogue between pediatricians and their radiologic colleagues is vital.
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