Accuracy of ultrasound in the diagnosis of classic metaphyseal lesions using radiographs as the gold standard.

BACKGROUND: Diagnosis of classic metaphyseal lesions (CMLs) in children suspected for child abuse can be challenging. Ultrasound (US) can potentially help diagnose CMLs. However, its accuracy is unknown. OBJECTIVE: To evaluate the accuracy of US in the diagnosis of CMLs using skeletal survey reports as the gold standard. MATERIALS AND METHODS: US of the metaphysis was performed in three patient groups age <1 year. Informed consent was obtained for patients scheduled for renal US (Group 1) and for patients scheduled for skeletal surveys for possible child abuse (Group 2). Targeted US was also performed in selected patients to evaluate for possible CML suspected on radiographs (Group 3). In Groups 1 and 2, US was performed of both distal femurs, and of either the right or left proximal and distal tibia. Two radiologists (Rad1 and Rad2) independently reviewed the US studies, blinded to history and other imaging. US sensitivity and specificity were calculated using the following gold standards: CML definitely seen on skeletal survey (positive), CML definitely not seen on skeletal survey or part of renal US group (negative). Cases where the skeletal survey was indeterminate for CML were excluded. Kappa statistics were used to evaluate interobserver variability. RESULTS: Two hundred forty-one metaphyseal sites were evaluated by US in 63 children (mean age: 5 months; 33 males); 34 had skeletal surveys and 29 had renal US. Kappa for the presence of CML was 0.70 with 95.7% agreement. US sensitivity was 55.0% and 63.2% and the specificity was 97.7% and 96.7% for Rad1 and Rad2, respectively. CONCLUSION: US has low sensitivity and high specificity in CML diagnosis. Thus, negative US does not exclude CML, but when the radiographs are equivocal, positive US can help substantiate the diagnosis.

Ultrasound evaluation of right diaphragmatic eventration and hernia.

BACKGROUND: A hernia is due to a defect in the diaphragm. An eventration is due to a thinned diaphragm with no central muscle. Distinguishing right diaphragmatic hernia from eventration on chest radiographs can be challenging if no bowel loops are herniated above the diaphragm. Experience is limited with postnatal ultrasound (US) evaluation of diaphragmatic hernia or eventration. OBJECTIVE: To evaluate for specific US signs in the diagnosis of right diaphragmatic hernia and eventration. MATERIALS AND METHODS: We identified all patients (January 2007-December 2017) with right diaphragm US and surgery for eventration or hernia. We reviewed medical charts, and US images/reports for clinical presentation and diaphragm abnormalities. Surgical diagnosis was considered the reference standard. RESULTS: Seventeen children (mean age: 5 months) had US examination before surgery for hernia (n=9) or eventration (n=8). The most common presentation was respiratory distress. In the US reports, hernia was correctly diagnosed in all patients and three patients with eventration were misdiagnosed as hernia, yielding 100% sensitivity and 62.5% specificity. In a retrospective evaluation of the US studies, a combination of folding of a free muscle edge with a narrow angle waist had 100% specificity for hernia and was seen in 7/9 children with hernia. Combination of a broad angle waist and hypoechoic strip of diaphragmatic muscle covering the waist had 100% specificity for eventration and was demonstrated in 4/8 children with eventration. Five of 17 patients (31.6%) had no specific sign that differentiated hernia from eventration. CONCLUSION: On US, folding of the free edge of the diaphragm and a narrow angle waist are specific for hernia; a broad angle waist with muscle covering the elevated area is specific for eventration. Definitive differentiation between eventration and hernia may not be possible in about a third of patients.