Urinary excretion of low-osmolar contrast media during small-bowel follow-through studies in infants is not definitive evidence of bowel perforation.

BACKGROUND: Presence of contrast agent in the urinary system in infants after small-bowel follow-through study with low-osmolar contrast media has been described as a sign of bowel perforation. OBJECTIVE: To evaluate how often the presence of contrast agent in the bladder after small-bowel follow-through is a reliable sign of bowel perforation or necrosis. MATERIALS AND METHODS: From the radiology information system, we retrieved imaging reports of infants evaluated with small-bowel follow-through and findings of contrast agent in the bladder. We retrieved demographic and clinical information from the medical records. Presence of bladder contrast medium was considered true-positive evidence of bowel perforation or necrosis if confirmed by pneumoperitoneum, extraluminal contrast agent, surgery or pathology within 3 days of the small-bowel follow-through. False-positives for bowel perforation or necrosis were based on surgical findings or clinical follow-up. RESULTS: Of the 207 infants who had small-bowel follow-through, 18 infants (12 boys; mean age 50 days, range 14 days to 8.5 months) had contrast medium in the bladder after the small-bowel follow-through. Fifteen of the 18 (83.3%) had a history of prematurity and 11 had prior abdominal surgery. Four of the 18 (22.2%) had bowel perforation or necrosis at surgery or pathology performed more than 3 days after the small-bowel follow-through and were considered indeterminate and excluded. Eight of the remaining 14 infants (57.1%) had bowel perforation or necrosis based on surgical evidence of perforation or pathology confirmation of necrosis (n=6), pneumoperitoneum (n=1) or contrast agent leakage from enterocutaneous fistula (n=1). Six of the 14 (42.9%) were false-positives, without evidence of bowel perforation or necrosis based on clinical follow-up (n=4) or surgery (n=2). CONCLUSION: Demonstration of urinary contrast agent post small-bowel follow-through with low-osmolar contrast medium in newborns/infants with complex medical problems is not a definitive indication of bowel perforation or necrosis. More than one-third of our patients with contrast medium in the bladder did not have bowel perforation or necrosis.

Whole-Spine MRI in Children With Suspected Abusive Head Trauma.

BACKGROUND. Abusive head trauma (AHT) in children has recently been associated with findings on cervical spine MRI. OBJECTIVE. The purpose of this study was to evaluate whether whole-spine MRI in children with suspected AHT shows additional abnormalities not identified on cervical spine MRI. METHODS. This retrospective study included 256 children younger than 3 years old (170 boys, 86 girls; mean age, 5.9 months) who underwent skeletal survey and head MRI for suspected child abuse from January 2019 to December 2020. Per institutional protocol, children with suspected AHT also underwent whole-spine MRI. AHT diagnoses were established by a combination of clinical information from medical record review and injuries described in reports from skeletal survey, head MRI, and head CT (if performed). Two pediatric neuroradiologists independently reviewed whole-spine MRI examinations for presence and level of intraspinal hemorrhage (classified as subarachnoid, subdural, or epidural), ligamentous injury, spinal cord edema, and vertebral fractures; subdural hematoma, epidural hematoma, ligamentous injury, and fracture unidentified by skeletal survey were considered major findings. Interobserver agreement was assessed; a third radiologist resolved discrepancies. Findings were summarized with attention to injuries isolated to the thoracolumbar spine. RESULTS. A total of 148 of 256 (57.8%) children underwent whole-spine MRI. AHT was diagnosed in 79 of 148 (53.4%) children who underwent whole-spine MRI versus in 2 of 108 (1.9%) who did not undergo whole-spine MRI (p < .001). Interobserver agreement, expressed as kappa coefficient, was 0.90 for intraspinal hemorrhage, 0.69 for ligamentous injury, 0.66 for spinal cord edema, and 0.95 for fracture. A total of 57 of 148 (38.5%) whole-spine MRI examinations showed injuries, and 34 of 148 (23.0%) showed injuries localized to the thoracolumbar spine. A total of 47 of 148 (31.8%) whole-spine MRI examinations showed major findings, of which 24 (51.1%) were localized to the thoracolumbar spine. Isolated thoracolumbar injuries included 23 of 34 spinal subdural hematomas, 2 of 3 spinal epidural hematomas, and 9 of 11 vertebral fractures, including five fractures not identified by skeletal survey. Diagnosis of AHT was more common in children with positive, versus negative, whole-spine MRI examinations (76.8% vs 39.1%; p < .001). CONCLUSION. In children with suspected AHT, whole-spine MRI commonly shows isolated thoracolumbar injuries. CLINICAL IMPACT. The results support performing whole-spine MRI rather than cervical spine MRI in children with suspected AHT.

Radiologists' Diagnostic Performance in Differentiation of Rickets and Classic Metaphyseal Lesions on Radiographs: A Multicenter Study.

BACKGROUND. Despite evidence supporting the specificity of classic metaphyseal lesions (CML) for the diagnosis of child abuse, some medicolegal practitioners claim that CML result from rickets rather than trauma. OBJECTIVE. The purpose of this study was to evaluate radiologists' diagnostic performance in differentiating rickets and CML on radiographs. METHODS. This retrospective seven-center study included children younger than 2 years who underwent knee radiography from January 2007 to December 2018 and who had either rickets (25-hydroxyvitamin D level < 20 ng/mL and abnormal knee radiographs) or knee CML and a diagnosis of child abuse from a child abuse pediatrician. Additional injuries were identified through medical record review. Radiographs were cropped and zoomed to present similar depictions of the knee. Eight radiologists independently interpreted radiographs for diagnoses of rickets or CML, rated confidence levels, and recorded associated radiographic signs. RESULTS. Seventy children (27 girls, 43 boys) had rickets; 77 children (37 girls, 40 boys) had CML. Children with CML were younger than those with rickets (mean, 3.7 vs 14.2 months, p < .001; 89.6% vs 5.7% younger than 6 months; 3.9% vs 65.7% older than 1 year). All children with CML had injuries in addition to the knee CML identified at physical examination or other imaging examinations. Radiologists had almost perfect agreement for moderate- or high-confidence interpretations of rickets (κ = 0.92) and CML (κ = 0.89). Across radiologists, estimated sensitivity, specificity, and accuracy for CML for moderate- or high-confidence interpretations were 95.1%, 97.0%, and 96.0%. Accuracy was not significantly different between pediatric and nonpediatric radiologists (p = .20) or between less experienced and more experienced radiologists (p = .57). Loss of metaphyseal zone of provisional calcification, cupping, fraying, and physeal widening were more common in rickets than CML, being detected in less than 4% of children with CML. Corner fracture, bucket-handle fracture, subphyseal lucency, deformed corner, metaphyseal irregularity, and subperiosteal new bone formation were more common in CML than rickets, being detected in less than 4% of children with rickets. CONCLUSION. Radiologists had high interobserver agreement and high diagnostic performance for differentiating rickets and CML. Recognition that CML mostly occur in children younger than 6 months and are unusual in children older than 1 year may assist interpretation. CLINICAL IMPACT. Rickets and CML have distinct radiographic signs, and radiologists can reliably differentiate these two entities.

Initial experience with contrast-enhanced ultrasound in the first week after liver transplantation in children: a useful adjunct to Doppler ultrasound.

BACKGROUND: Doppler US is the primary screening for post-liver transplant vascular complications, but indeterminate findings require further imaging. OBJECTIVE: To evaluate whether contrast-enhanced US improves diagnostic assessment of vascular complications suspected by Doppler US. MATERIALS AND METHODS: We retrospectively reviewed Doppler US and contrast-enhanced US studies obtained in the first week following liver transplant. Doppler US was performed twice daily for the first 5 postoperative days, and CEUS in the first postoperative day and when vascular complications were suspected. We correlated Doppler US and CEUS with surgical findings, and clinical and imaging follow-up. We evaluated Doppler US and CEUS quality in demonstrating the main hepatic artery (HA) at the porta hepatis as follows: Grade 0 = not seen, Grade 1 = only segments, Grade 2 = entire main HA, and Grade 3 = entire main HA to the intrahepatic branching. We used a Wilcoxon signed rank test to test the difference between Doppler US and CEUS methods. RESULTS: Twenty-nine children (15 girls, 14 boys) were identified, with median age 2.2 years (range 0.5-17.6 years). The most common transplant indication was biliary atresia (n=13). There was significantly (P<0.0001) improved main HA visualization with CEUS. In five children, CEUS was performed to evaluate suspected vascular complications; CEUS confirmed normal vascularity in two. CEUS demonstrated portal vein thrombosis (n=2) and main HA thrombosis (n=1), confirmed at surgery. In one child the main HA thrombosis was missed; marked HA narrowing was seen retrospectively on CEUS. CONCLUSION: Immediately following liver transplantation, CEUS improves main HA visualization and diagnostic assessment of vascular complications.

Retroperitoneal and Pelvic Lymph Nodes in Children: What Is Normal?

OBJECTIVE. The purpose of this study was to evaluate size criteria for retroperitoneal and pelvic lymph nodes in healthy children. MATERIALS AND METHODS. We identified all trauma patients younger than 18 years old without underlying disease and with CT scans without abnormalities in the abdomen and pelvis during 2014-2015. Two pediatric radiologists reviewed the studies independently and recorded the number of retroperitoneal and pelvic lymph nodes with a long diameter 5 mm or greater and the size (two perpendicular diameters) of the largest lymph node in five anatomic locations. Discrepant results were reviewed in consensus. The relationship of short diameter to age and interobserver variability was evaluated. RESULTS. A total of 166 patients (86 boys) with a mean age of 7.2 years old (range, 0.1-18.0 years old) were identified. More than 95% of lymph nodes in the retroperitoneum and pelvis had a short diameter measuring at most 7 and 8 mm, respectively, by consensus. The size of the largest short diameter of lymph nodes did not vary with age. More than four lymph nodes were identified in any anatomic location in only three patients, by only one of the radiologists. Agreement for lymph nodes with largest diameter of 5 mm or greater between radiologists ranged from 70.5% to 97.6% for the five anatomic locations with poor interobserver agreement (κ, 0.2-0.3). CONCLUSION. The size and number of retroperitoneal and pelvic lymph nodes in children are less than in adults. A short diameter threshold of 7 mm (retroperitoneal) and 8 mm (pelvic) and more than four lymph nodes with long diameter of 5 mm or greater in one location may define disease.

Establishing signs for acute and healing phases of distal tibial classic metaphyseal lesions.

BACKGROUND: Stages of healing for classic metaphyseal lesions (CMLs) are not well established. Follow-up skeletal surveys provide an opportunity to evaluate signs of healing CMLs. OBJECTIVE: To evaluate the sequence of CML healing phases by comparing initial and follow-up skeletal surveys in children with distal tibial CMLs on the initial survey. Findings could assist in child abuse investigations. MATERIALS AND METHODS: We identified all distal tibia CMLs with initial and follow-up skeletal surveys performed January 2009 through December 2018 at our institution. Two pediatric radiologists reviewed the surveys using Likert score from 1 (no CML) to 5 (definite CML). Only cases with score of 4 or 5 by both radiologists were selected for the study. The initial and 2-week follow-up skeletal surveys were reviewed in consensus for presence of the following signs: corner fracture, thin bucket handle fracture, thick bucket handle fracture, bucket handle fracture with endochondral bone filling the gap, subphyseal lucency, deformed corner, and subperiosteal new bone formation. We used the Kruskal-Wallis test to evaluate for significant difference in thickness among thin bucket handle fracture, thick bucket handle fracture, and bucket handle fracture with endochondral bone filling the gap. RESULTS: We included 26 children (12 girls) with age range 1-9.9 months who had a combined 34 distal tibia CMLs. Thin bucket handle fracture (n=13, 38.2%) was only seen on initial survey. On follow-up, six children had thick bucket handle fracture and four had bucket handle fracture with endochondral bone filling the gap. Fourteen thick bucket handle fractures (n=9) or bucket handle fractures with endochondral bone filling the gap (n=5) were noted on initial surveys; on follow-up, three (21.4%) had deformed corner, one (7.1%) had corner fracture, one (7.1%) had subphyseal lucency, and five (35.7%) were normal. None demonstrated thin bucket handle fracture on follow-up. Two of the nine (22.2%) thick bucket handle fractures became thicker, and 3/9 (33.3%) became bucket handle fractures with endochondral bone filling the gap. The metaphysis normalized in 8/34 (23.5%) CMLs on follow-up surveys. The thickness of thin bucket handle fracture was less than 1 mm (mean±standard deviation [SD] = 0.6±0.2 mm), which was significantly thinner (P<0.0001) compared with thick bucket handle fracture (1.7±0.5 mm) and bucket handle fracture with endochondral bone filling the gap (1.9±0.6 mm). CONCLUSION: The lack of thin bucket handle fractures on any follow-up skeletal surveys suggests this sign represents an acute phase of injury. The next phases of healing appear to be thick bucket handle fracture followed by bucket handle fracture with endochondral bone filling the gap. It is important to note that normalization of the metaphysis at 2-week follow-up does not exclude CML because this was seen in about one-fifth of cases.

Osteomyelitis of the ribs in children: a rare and potentially challenging diagnosis.

BACKGROUND: Rib osteomyelitis is rare in children and can mimic other pathologies. Imaging has a major role in the diagnosing rib osteomyelitis. OBJECTIVE: To evaluate clinical presentation and imaging findings in children with rib osteomyelitis. MATERIALS AND METHODS: We performed a retrospective (2009-2018) study on children with rib osteomyelitis verified by either positive culture or pathology. We excluded children with multifocal osteomyelitis or empyema necessitans. We reviewed medical charts for clinical, laboratory and pathology data, and treatment. All imaging modalities for rib abnormalities were evaluated for presence and location of osteomyelitis and abscess. We calculated descriptive statistics to compare patient demographics, clinical presentation and imaging findings. RESULTS: The study group included 10 children (6 boys, 4 girls), with an average age of 7.3 years (range, 3 months to 15.9 years). The most common clinical presentations were fever (n=8) and pain (n=5). Eight children had elevated inflammatory indices (leukocytosis, erythrocyte sedimentation rate [ESR], C-reactive protein [CRP]). Localized chest wall swelling was found initially in six children and later in two more children. Rib osteomyelitis was suspected on presentation in only two children. All children had chest radiographs. Rib lytic changes were found on only one chest radiograph, in two of the four ultrasound studies, and in four of eight CTs. Bone marrow signal abnormalities were seen in all eight MRIs. In nine children the osteomyelitis involved the costochondral junction. Six children had an associated abscess. Staphylococcus aureus was cultured in eight children. Osteomyelitis was diagnosed based on pathology in one child with negative cultures. CONCLUSION: While rib osteomyelitis is rare, imaging findings of lytic changes at the costochondral junction combined with a history of fever, elevated inflammatory markers or localized soft-tissue swelling in the chest should raise suspicion for this disease.

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.

Compliance With Skeletal Surveys for Child Abuse in General Hospitals: A Statewide Quality Improvement Process.

OBJECTIVE. The purpose of this study is to perform a statewide quality improvement process to improve compliance with the American College of Radiology (ACR) guidelines in performing skeletal surveys for suspected child abuse. SUBJECTS AND METHODS. We prospectively identified all outside hospital skeletal surveys for suspected child abuse in children younger than 3 years referred to our tertiary children's hospital in 2016-2017. We included a 3-month baseline and 21-month intervention period. The quality improvement process was based on sending educational material to all ACR member radiologists in the state and making telephone calls to radiology technologist team leaders whenever the surveys were not compliant, followed by e-mails with guidance on performing skeletal surveys. We documented the views obtained and compared them with the ACR guidelines. The percentage of compliance with each individual view was assessed with the chi-square test. The total number of compliant views per survey was evaluated with ANOVA. RESULTS. Two hundred twenty-seven patients (105 female) with a mean age of 0.8 year (SD, 0.67 year; range, 0.01-3 years) were evaluated. These 227 surveys (baseline, n = 27; postintervention, n = 200) were performed at 69 different outside hospitals. Compliance significantly (p = 0.006) improved from 25.9% (7/27) during baseline to 54.0% (108/200) after intervention. There was a nonsignificant trend of improved compliance between the first (51.9%; 41/79) and last 7-month (62.3%; 33/53) periods of intervention. Among individual views, only rib oblique views showed significantly (p = 0.02) improved compliance after the intervention, from 51.9% (14/27) to 73.5% (147/200). CONCLUSION. The compliance rate with ACR guidelines for skeletal surveys in suspected child abuse at outside general hospitals significantly increased after implementation of a quality improvement process.

Ultrasound findings in classic metaphyseal lesions: emphasis on the metaphyseal bone collar and zone of provisional calcification.

BACKGROUND: The classic metaphyseal lesion (CML) is highly specific for non-accidental trauma in infants. While the radiographic findings are well documented, there is little literature on the ultrasound (US) appearance. OBJECTIVE: To evaluate US findings in CMLs identified on radiographs. MATERIAL AND METHODS: This institutional review board-approved, retrospective evaluation of targeted US of CMLs was performed in selected groups of children from 2014 to 2017. Only CMLs confidently identified on radiography by a consensus of two radiologists were included. US images were obtained with a linear transducer, including longitudinal images at lateral, anterior, medial and posterior aspects. Two pediatric radiologists evaluated the US appearance, specifically the metaphyseal bone collar for thickness, deformity and fracture, as well as the sonographic zone of provisional calcification for irregularity and appearance of multiple lines. Radiography was the reference standard. RESULTS: Twenty-two patients (13 female; mean age: 4.2 months) were identified, with 39 CMLs in the tibia (n=22), femur (n=11), humerus (n=3), radius (n=2) and fibula (n=1). Thirty-three of the 39 CMLs (85%) were identified on US, while 6 (15%) were not seen (false negatives). Thirty of the 39 (77%) had metaphyseal bone collar thickening, 29 (74%) had collar deformity and 12 (31%) had visible fracture of the collar. At the sonographic zone of provisional calcification, 16/39 (41%) had irregularity and 5 (13%) had multiple lines visible. CONCLUSION: Identifying metaphyseal bone collar and zone of provisional calcification abnormalities is key to recognizing CMLs on US. While additional studies are necessary to evaluate the accuracy of US in the diagnosis of CMLs, our findings suggest US may have a potential role in either confirming or evaluating radiographically equivocal/occult CMLs.

The added value of a second read by pediatric radiologists for outside skeletal surveys.

BACKGROUND: Fractures are the second most common finding in non-accidental trauma after cutaneous signs. Interpreting skeletal surveys could be challenging as some fractures are subtle and due to anatomical variations that can mimic injuries. OBJECTIVE: To determine the effect of a second read by a pediatric radiologist of skeletal surveys for suspected non-accidental trauma initially read at referring hospitals by general radiologists. MATERIALS AND METHODS: In 2016 and 2017, we identified all patients referred to our children's hospital with previous surveys performed and read at a community hospital by an outside radiologist. We excluded patients older than 3 years and studies performed at a children's hospital. The surveys were reviewed by a pediatric radiologist with the printed outside report available. Surveys with disagreement between outside read and pediatric radiologist read were reviewed by a second pediatric radiologist. A disagreement in the second read included only definite discrepant findings agreed upon by both pediatric radiologists. The Fisher exact test was performed to compare the ratio of discrepancies between readers in normal and abnormal surveys. RESULTS: Two hundred twenty-five surveys were performed (120 male) at 62 referring hospitals, with a mean patient age of 10.5 months (range: 5 days-3 years). The outside read identified fractures in 104/225 (46.2%) surveys. Thirty-seven of the 225 (16.4%) contained discrepancies in interpretation (n=111). Most of these disagreements (29/37, 78.4%) resulted in a significant change in the report. There was a significant (P<0.0001) difference between disagreement rate in outside read negative (4/111, 3.2%) and positive surveys (34/104, 31.7%). The second read identified additional fractures in 22/225 (9.8%) of the surveys and disagreed with first-read fractures in 17/256 (7.6%). Four of 19 (21.1%) classic metaphyseal lesions diagnosed by the outside read were normal variants; 18 classic metaphyseal lesions were missed by the outside read. CONCLUSIONS: This study supports second reads by pediatric radiologists of skeletal surveys for non-accidental trauma.

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.

Changes in femoral head size and growth rate in young children with severe developmental dysplasia of the hip.

BACKGROUND: Developmental dysplasia of the hip (DDH) is known to result in smaller femoral head size in toddlers; however, alterations in femoral head size and growth have not been documented in infants. OBJECTIVE: To determine with ultrasound (US) whether femoral head size and growth are altered in infants (younger than 1 year of age) with severe DDH. MATERIALS AND METHODS: We identified all patients at our tertiary care children's hospital from 2002 to 2014 who underwent US for DDH. We included studies with at least one hip with severe DDH, defined as <25% coverage of the femoral head, and excluded teratological DDH. We constructed a control group of randomized patients with normal US studies. Two pediatric radiologists blinded to diagnosis measured bilateral femoral head diameter. Inter-reader variability and femoral head diameter difference between dislocated and contralateral normal femoral heads were evaluated. Mean femoral head diameters were compared across types of hip joint; femoral head growth rates per month were calculated. RESULTS: Thirty-seven children with DDH (28 female) were identified (median age: 33 days). The control group contained 75 children (47 female) with a median age of 47 days. Fifty-three of the 74 hips in the study group had severe DDH. Twenty-four children with DDH had completely dislocated hips (nine bilateral, five with contralateral severe subluxations). Thirteen other children had severe subluxation, two bilaterally. There was good inter-reader agreement in the normal femoral head group and moderate agreement in the severe DDH group. In the study group, severe DDH femoral head diameter was significantly smaller than their contralateral normal hip. Severe DDH femoral head diameter was significantly smaller than normal femoral head diameter in the control group. The severe DDH femoral head growth rate was slightly less but not significantly slower than normal femoral head growth rate in the study group. CONCLUSION: On US during infancy, femoral head size is significantly reduced in severe cases of DDH.

Double-read of skeletal surveys in suspected non-accidental trauma: what we learned.

BACKGROUND: Missing a fracture in a child on skeletal surveys for suspected non-accidental trauma can have devastating results. Double-read has the potential to improve fracture detection. However the yield of double-read is unknown. OBJECTIVE: To determine the advantage of double-read versus single-read of radiographic skeletal surveys for suspected non-accidental trauma. MATERIALS AND METHODS: The study was performed in two phases. In the first phase (April 2013 to September 2013), double-read was performed for all skeletal surveys obtained during weekday working hours. Because we had no new double-read findings in studies initially read as negative, we conducted a second phase (January 2014 to March 2014). In the second phase we limited double-reads to skeletal surveys found positive on the first read. At the end of this period, we retrospectively performed double-read for all initially negative skeletal surveys. We excluded follow-up skeletal surveys. The difference in discrepancy (new fracture or false diagnosis of a fracture) ratio between negative and positive skeletal surveys was evaluated using the Fisher exact test, and change in discrepancy ratio between the first and second study phases was evaluated using the stratified Cochran-Mantel-Haenszel test. RESULTS: Overall in the two phases, 178 skeletal surveys were performed in 178 children (67 girls) with mean age of 9 months (range 3 days to 3.7 years). Double-read found 16 discrepancies in 8/178 (4.5%) skeletal surveys. Seven of these studies showed additional fractures (n=15). In one study, an initial read of a skull fracture was read as a variant on the second read. There was a significant (P=0.01) difference between rate of disagreement in negative skeletal surveys (1/104, 1.0%) and positive skeletal surveys (7/74, 9.5%). No significant change in disagreement rate was demonstrated between the two phases of the study (P=0.59). CONCLUSION: Double-read of skeletal survey for suspected non-accidental trauma found false-negative fractures in a few cases and rarely found false-positive diagnosis of a fracture. Double-read uncommonly found discrepancies in an initially normal skeletal survey. Limiting double-read to initially positive studies improves the yield of the double-read.

How accurate is size-specific dose estimate in pediatric body CT examinations?

BACKGROUND: Size-specific dose estimate is gaining increased acceptance as the preferred index of CT dose in children. However it was developed based on non-clinical data. OBJECTIVE: To compare the accuracy of size-specific dose estimate (SSDE) based on geometric and body weight measures in pediatric chest and abdomen CT scans, versus the more accurate [Formula: see text] (mean SSDE based on water-equivalent diameter). MATERIALS AND METHODS: We retrospectively identified 50 consecutive children (age <18 years) who underwent chest CT examination and 50 children who underwent abdomen CT. We measured anteroposterior diameter (DAP) and lateral diameter (DLAT) at the central slice (of scan length) of each patient and calculated DAP+LAT (anteroposterior diameter plus lateral diameter) and DED (effective diameter) for each patient. We calculated the following in each child: (1) SSDEs based on DAP, DLAT, DAP+LAT, DED, and body weight, and (2) SSDE based on software calculation of mean water-equivalent diameter ([Formula: see text] adopted standard within our study). We used intraclass correlation coefficient (ICC) and Bland-Altman analysis to compare agreement between the SSDEs and [Formula: see text]. RESULTS: Gender and age distribution were similar between chest and abdomen CT groups; mean body weight was 37 kg for both groups, with ranges of 6-130 kg (chest) and 8-107 kg (abdomen). SSDEs had very strong agreement (ICC>0.9) with [Formula: see text]. SSDEs based on DLAT had 95% limits of agreement of up to 43% with [Formula: see text]. SSDEs based on other parameters (body weight, DAP, DAP+LAT, DED) had 95% limits of agreement of up to 25%. CONCLUSION: Differences between SSDEs calculated using various indications of patient size (geometric indices and patient weight) and the more accurate [Formula: see text] calculated using proprietary software were generally small, with the possible exception for lateral diameter, and provide acceptable dose estimates for body CT in children.

Effect of body size on dose reduction with longitudinal tube current modulation in pediatric patients.

OBJECTIVE: The purpose of the study was to evaluate whether dose reduction by tube current modulation in pediatric abdominal CT depends on patient body size. MATERIALS AND METHODS: A 12-month (February 2012 through January 2013) retrospective evaluation of consecutive abdominal 128-MDCT examinations was performed. All studies were performed with longitudinal (z-axis) tube current modulation. Dose reduction from tube current modulation in every CT acquisition was recorded and compared with body weight. In addition, 100 randomized CT abdominal scans were evaluated for average and SD of the water-equivalent diameter along the z-axis. RESULTS: The results include 466 abdominal CT scans of 369 children (172 girls, 197 boys; age range, 3 weeks-18 years; average, 9.2 years; body weight range, 3.5-130 kg; average, 31 kg). The average tube current-time reduction was 19%. Dose reduction was least effective (p<0.05; average, 11%) for body weight less than 20 kg. The least variability (SD/average) of water-equivalent diameter along the z-axis was found for body weights greater than 20 kg (5.0%) and 20-40 kg (5.9%) (p<0.05). Dose reduction was most effective (p<0.05; average, 30%) at the body weight range of 60-100 kg. CONCLUSION: Dose reduction with automated tube modulation depends on body weight and is less effective in children with a small body size. One of the reasons for this phenomenon could be a closer to uniform water-equivalent diameter along the z-axis in children with a small body size.

Value of magnetic resonance imaging in evaluating the pancreatic allograft transplant complications.

PURPOSE: To retrospectively investigate the value of magnetic resonance imaging (MRI) in detecting complications following pancreas transplant. MATERIALS AND METHODS: Institutional review board approved this retrospective HIPAA-compliant study and waived informed patient consent. We identified all allograft pancreas transplant patients at our institution from 2001 to January 2014 who had all pertinent post-transplant imaging and clinical data available. Transplant type was documented. Patients were divided into two groups according to post-transplant period (group A; <12 months, group B; ≥12 months). We evaluated the parenchymal enhancement using contrast-enhanced MRI of the allograft and determined the mean percentage of parenchymal enhancement (MPPE) overall and in various abnormalities, the vessel patency, any peripancreatic fluid collection, and the ductal anatomy. We correlated these with clinical results using t test, χ (2), and Fisher's exact test; p < 0.05 was considered significant. RESULTS: 51 patients (34 male, mean age 43.7 years) were identified, 28 (55%) of whom had abnormal imaging findings; transplant rejection-related necrosis (n = 7), fluid collections (n = 7), vascular stenosis (n = 4), isolated venous thromboses (n = 3), acute pancreatitis (n = 3), pancreatic and peripancreatic abscesses (n = 2), pseudoaneurysm (n = 1), and small-bowel obstruction (n = 1). Pre vs. post-contrast pancreatic MPPE at 1 min was 120% in the normal allografts and 115% in the allografts with pancreatitis and without necrosis (p > 0.05). MPPE at 1 min was only 9% in the allografts rejections with necrosis/infarction. More complications were found in group A than group B (p < 0.05). CONCLUSIONS: Contrast-enhanced MRI is useful for the non-invasive assessment of pancreas transplant complications.

Testicular microlithiasis in children and associated testicular cancer.

PURPOSE: To evaluate the prevalence of testicular microlithiasis (TM) in children who have undergone scrotal ultrasonography (US) and their association with testicular tumors. MATERIALS AND METHODS: This HIPAA-compliant study with waiver of informed consent was approved by the institutional review board. From 2003 to 2012, all patients with scrotal US and report mentioning calcifications or microlithiasis and all patients with testicular tumors from pathology database were identified. US studies were evaluated for the type of TM (classic ≥5 microliths or limited <5 microliths in a single view) and change in follow-up studies if available. Medical charts were reviewed for US indication, underlying medical conditions, and pathologic abnormalities, when available. Fisher exact test was used to analyze the association of testicular tumors and TM. RESULTS: A total of 3370 boys had scrotal US, 83 (2%) of whom had TM or microcalcifications in the report. TM was usually bilateral (n = 62, 75%) and classic (n = 59, 71%) type.TM was significantly less common in those younger than 2 years of age than in older age groups (0.1% vs 3.1%, P < .0001). The most common indication for US was scrotal pain (40 of 83 patients, 48%), and the most common associated medical condition was cryptorchidism (nine of 83 patients, 11%). Testicular tumor was significantly more likely in boys with TM (12% vs 0.3%, P < .01). Five (83%) of six patients with premalignant or benign tumors had a premalignant condition (cryptochydism in two and Peutz-Jeghers syndrome in three). Four patients with TM had malignant testicular tumors, all diagnosed after the age of 16 years. CONCLUSION: TM has a prevalence of 2% in boys who undergo scrotal US. It is most commonly bilateral, classic type, and stable at follow-up studies. There is a significant association of TM and testicular tumors. Malignant tumors were seen only in adolescent boys.

Is the new ACR-SPR practice guideline for addition of oblique views of the ribs to the skeletal survey for child abuse justified?

OBJECTIVE: The purpose of our study was to determine whether adding oblique bilateral rib radiography to the skeletal survey for child abuse significantly increases detection of the number of rib fractures. MATERIALS AND METHODS: We identified all patients under 2 years old who underwent a skeletal survey for suspected child abuse from January 2003 through July 2011 and who had at least one rib fracture. These patients were age-matched with control subjects without fractures. Two randomized radiographic series of the ribs were performed, one containing two views (anteroposterior and lateral) and another with four views (added right and left oblique). Three fellowship-trained radiologists (two in pediatrics and one in trauma) blinded to original reports independently evaluated the series using a Likert scale of 1 (no fracture) to 5 (definite fracture). We analyzed the following: sensitivity and specificity of the two-view series for detection of any rib fracture and for location (using the four-view series as the reference standard), interobserver variability, and confidence level. RESULTS: We identified 212 patients (106 with one or more fractures and 106 without). The sensitivity and specificity of the two-view series were 81% and 91%, respectively. Sensitivity and specificity for detection of posterior rib fractures were 74% and 92%, respectively. There was good agreement between observers for detection of rib fractures in both series (average kappa values of 0.70 and 0.78 for two-views and four-views, respectively). Confidence significantly increased for four-views. CONCLUSION: Adding bilateral oblique rib radiographs to the skeletal survey results in increased rib fracture detection and increased confidence of readers.

Optimization of hybrid iterative reconstruction level in pediatric body CT.

OBJECTIVE: The objective of our study was to attempt to optimize the level of hybrid iterative reconstruction (HIR) in pediatric body CT. MATERIALS AND METHODS: One hundred consecutive chest or abdominal CT examinations were selected. For each examination, six series were obtained: one filtered back projection (FBP) and five HIR series (iDose(4)) levels 2-6. Two pediatric radiologists, blinded to noise measurements, independently chose the optimal HIR level and then rated series quality. We measured CT number (mean in Hounsfield units) and noise (SD in Hounsfield units) changes by placing regions of interest in the liver, muscles, subcutaneous fat, and aorta. A mixed-model analysis-of-variance test was used to analyze correlation of noise reduction with the optimal HIR level compared with baseline FBP noise. RESULTS: One hundred CT examinations were performed of 88 patients (52 females and 36 males) with a mean age of 8.5 years (range, 19 days-18 years); 12 patients had both chest and abdominal CT studies. Radiologists agreed to within one level of HIR in 92 of 100 studies. The mean quality rating was significantly higher for HIR than FBP (3.6 vs 3.3, respectively; p < 0.01). HIR caused minimal (0-0.2%) change in CT numbers. Noise reduction varied among structures and patients. Liver noise reduction positively correlated with baseline noise when the optimal HIR level was used (p < 0.01). HIR levels were significantly correlated with body weight and effective diameter of the upper abdomen (p < 0.01). CONCLUSION: HIR, such as iDose(4), improves the quality of body CT scans of pediatric patients by decreasing noise; HIR level 3 or 4 is optimal for most studies. The optimal HIR level was less effective in reducing liver noise in children with lower baseline noise.