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The corona mortis (CM) is a vascular connection between the obturator and external iliac or internal epigastric vessels that has historically been identified as a source of hemorrhage in pelvic surgery. However, its frequency, location, proximity to the osteotomies performed, vascular contributions and impact on blood loss in patients undergoing periacetabular osteotomy (PAO) are unknown. We sought to identify the frequency, origin, location relative to osteotomies performed during surgery and impact on blood loss of the CM. Preoperative magnetic resonance imaging (MRI) of the hips of 28 adolescent patients (56 hips) undergoing PAO was retrospectively reviewed for the presence of a CM. When identifiable, the size, nature (arterial or venous), orientation, position relative to the iliopectineal eminence (IPE) and associated estimated blood loss (EBL) were recorded. 75% (21/28) of patients possessed an identifiable, ipsilateral CM to the site of PAO, 90% of which were venous and 10% arterial. The vessel was typically 8.3 ± 3.8 mm medial and 11.1 ± 5.3 mm caudal from the anterosuperomedial edge of the IPE. There was no significant difference in the amount of EBL (519 ± 260 versus 694 ± 369 ml) or need for post-op transfusions (1/21 versus 0/7) between patients who possessed a CM and those who did not, respectively ( P  = 0.21). CM was more prevalent in this study than previously reported. However, the presence of an ipsilateral CM was not associated with an increase in EBL or transfusion during routine PAO surgery using modern surgical techniques., (© The Author(s) 2021. Published by Oxford University Press.)

Background: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on a patient's skeletal maturity. To be clinically useful, radiologic assessments of skeletal maturity must demonstrate acceptable interrater reliability and accuracy., Purpose: The purpose of this study was to examine the interrater reliability among surgeons of varying experience levels and specialty training backgrounds when evaluating the skeletal maturity of the distal femur and proximal tibia of children and adolescents with patellofemoral instability., Study Design: Cohort study (diagnosis); Level of evidence, 3., Methods: Six fellowship-trained orthopaedic surgeons (3 pediatric orthopaedic, 2 sports medicine, and 1 with both) who perform a high volume of patellofemoral instability surgery examined 20 blinded knee radiographs and magnetic resonance images in random order. They assessed these images for clinically relevant growth (open physis) or clinically insignificant growth (closing/closed physis) remaining in the distal femoral and proximal tibial physes. Fleiss' kappa was calculated for each measurement. After initial ratings, raters discussed consensus methods to improve reliability and assessed the images again to determine if training and new criteria improved interrater reliability., Results: Reliability for initial assessments of distal femoral and proximal tibial physeal patency was poor (kappa range, 0.01-0.58). After consensus building, all assessments demonstrated almost-perfect interrater reliability (kappa, 0.99 for all measurements)., Conclusion: Surgical decision making and preoperative planning for children and adolescents with patellofemoral instability rely heavily on radiologic assessment of skeletal maturity. This study found that initial interrater reliability of physeal patency and clinical decision making was unacceptably low. However, with the addition of new criteria, a consensus-building process, and training, these variables became highly reliable., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: P.D.F. has received education payments from Smith & Nephew and hospitality payments from Medical Device Business Services. D.W.G. has received consulting fees from Arthrex; speaking fees from AO Trauma and Arthrex; faculty/speaker fees from Synthes; and royalties from Arthrex, Current Opinion in Pediatrics, Pega Medical, and Wolters Kluwer Health. S.M.S. has received research support from JRF and Vericel; consulting fees from DePuy/Medical Device Business Services, Moximed, Pfizer, and Smith & Nephew; speaking fees from Organogenesis and Vericel; royalties from Organogenesis; and hospitality payments from Fidia Pharma and Stryker. E.J.W. has received consulting fees from OrthoPediatrics. D.N.M. has received royalties from Springer. J.M.B. has received education payments and speaking fees from Steelhead Surgical and consulting fees from Smith & Nephew. H.B.E. has received education payments from Pylant Medical; faculty/speaker fees from Smith & Nephew, Pylant Medical, and Synthes; and hospitality payments from Arthrex. J.F. has received research support from Active Implants, Arthrex, Episurf, Fidia, JRF Ortho, Moximed, Novartis, Organogenesis, Samumed, Vericel, and Zimmer Biomet; education payments from Crossroads Orthopedics; consulting fees from Aesculap/B. Braun, Cartiheal, Cook Biotech, DePuy, Exactech, Moximed, Organogenesis, Regentis, RTI Surgical, Samumed, and ZKR Orthopedics; speaking fees from Aastrom Biosciences, Arthrex, Moximed, Organogenesis, and Vericel; royalties from Arthrex, Biopoly, DePuy, Organogenesis, Springer, and Thieme; and hospitality payments from Skeletal Kinetics. J.F. also has stock/stock options in MedShape and Ortho Regenerative Tech. B.E.H. has received education payments from Arthrex and Kairos Surgical, other financial or material support from Allosource and Vericel, and royalties from Springer and has stock/stock options in Imagen Technologies. J.L.K. has received education payments from Medwest and consulting fees from Flexion Therapeutics, has stock/stock options in Acuitive and Marrow Access Technologies, and is an employee of Marrow Access Technologies. D.K. has received education payments from Kairos Surgical and other financial or material support from Arthrex. R.A.M. has received research support from Zimmer, education payments from CDC Medical, and other financial or material support from Arthrex. L.H.R. has received education payments from Arthrex and consulting fees from GLG Consulting and Relief Health and has stock/stock options in Relief Health. S.L.S. has received research support from Arthrex; grant funding from DJO; education payments from Elite Orthopedics; and consulting fees from Arthrex, Ceterix, ConMed Linvatec, Flexion Therapeutics, GLG Consulting, JFR Ortho, Moximed, Olympus, and Vericel. M.T. has received grant support from DJO. P.W. has received research support from AlloSource and Ossur, education payments from Pylant Medical, and royalties from Elsevier. B.E.S.S. has received consulting fees, speaking fees, and royalties from Arthrex. S.N.P. has received education payments from CDC Medical, speaking fees from Synthes, and royalties from Wolters Kluwer Health. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

A previously healthy 3-week-old boy presented with 5 hours of marked fussiness, abdominal distention, and poor feeding. He was afebrile and well perfused. His examination was remarkable for localized abdominal tenderness and distention. He was referred to the emergency department in which an abdominal radiograph revealed gaseous distention of the bowel with a paucity of gas in the pelvis. Complete blood cell count and urinalysis were unremarkable. His ongoing fussiness and abnormal physical examination prompted consultation with surgery and radiology. Our combined efforts ultimately established an unexpected diagnosis., Competing Interests: POTENTIAL CONFLICT OF INTEREST: The authors have indicated they have no potential conflicts of interest to disclose., (Copyright © 2017 by the American Academy of Pediatrics.)

Background: Phalangeal microgeodic disease is a rare and benign self-limited condition involving the phalanges, often in the setting of cold exposure, with characteristic MR imaging abnormalities. Radiographic case descriptions are predominantly from Asia and Europe, with only seven cases using MR to characterize phalangeal microgeodic disease., Objective: In this study we describe the MR imaging appearance of unusual and striking phalangeal signal abnormality compatible with phalangeal microgeodic disease at our institution in North America., Materials and Methods: We retrospectively reviewed cases presenting at our institution with unusual or unexplained phalangeal signal abnormalities between 2001 and 2014. We reviewed the MR imaging appearances in conjunction with radiographs and any other available imaging investigations., Results: Of 189 examinations reviewed during the study period, 8 imaging studies in 6 patients met the study inclusion criteria. Signal abnormality was present in 57 of 112 phalanges (51%), frequently involving the distal phalanges (70%, 28 of 40), followed by the middle phalanges (56%, 18 of 32) and the proximal phalanges (28%, 11 of 40). The pattern of involvement was most commonly diaphysis (38%), followed by metaphysis (32%) and epiphysis (30%). The extent of MR signal abnormality was greater than that suspected based on clinical presentation or on radiographs., Conclusion: The presence of unexplained diffuse characteristic marrow involvement of multiple painful phalanges on MR images, often in the setting of cold exposure, should raise the possibility of phalangeal microgeodic disease. Consideration of this diagnosis based on MR findings would lead to a more conservative management and avoid unnecessary invasive diagnostic procedures.

Background: The three most common elbow fractures classically reported in pediatric orthopedic literature are supracondylar (50-70%), lateral condylar (17-34%), and medial epicondylar fractures (10%), with fractures of the proximal radius (including but not limited to fractures of the radial neck) being relatively uncommon (5-10%). Our experience at a large children's hospital suggests a different distribution., Objective: Our goals were (1) to ascertain the frequency of different elbow fracture types in a large pediatric population, and (2) to determine which fracture types were occult on initial radiographs but detected on follow-up., Materials and Methods: Review of medical records identified 462 children, median age 6 years and interquartile range for age of 4-8 years (range 0.8-18 years), who were diagnosed with elbow fractures at our institution over a 10-month period. Initial and follow-up radiographs were reviewed in blinded fashion independently by two experienced pediatric musculoskeletal radiologists to identify fracture types on initial and follow-up radiographs., Results: The most common fractures included supracondylar (n = 258, 56%), radial neck (n = 80, 17%), and lateral condylar (n = 69, 15%). Additional fractures were seen on follow-up exams in 32 children. Of these, 25 had a different fracture type than was identified on initial radiographs. The most common follow-up fractures were olecranon (n = 23, 72%), coronoid process (n = 4, 13%) and supracondylar (n = 3, 9%). Olecranon fractures were significantly more common on follow-up radiographs than they were on initial radiographs (n = 33, 7%; P < .0001). Twenty-six children had more than one fracture type on the initial radiograph. The most common fracture combinations were radial neck with olecranon (n = 9) and supracondylar with lateral condylar (n = 9)., Conclusion: Supracondylar fractures are the most frequent elbow fracture seen initially, followed by radial neck, lateral condylar, and olecranon fractures in a distribution different from what has been historically described. The relatively high frequency of olecranon fractures detected on follow-up speaks to their potentially occult nature. Careful attention to these areas is warranted in children with initially normal radiographs.

Background: Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation., Objective: The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes., Materials and Methods: We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available., Results: Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between rotator cuff tears and physeal patency (P > 0.05). Most patients were athletes (76%). Five tears were confirmed at surgery. Poor clinical follow-up limited evaluation of patient outcomes., Conclusion: Rotator cuff tears can be identified during MRI examination of symptomatic child and adolescent shoulders and often consist of tear patterns associated with repetitive microtrauma in overhead athletic activities or with single traumatic events. Rotator cuff tears are seen throughout the range of skeletal maturity, often coexist with labral tears and typically are found in athletes.

Intraneural ganglion cysts are uncommon cystic lesions of peripheral nerves that are typically encountered in adults. In the lower extremity, the peroneal nerve is most frequently affected with involvement of the tibial nerve much less common. This article describes a tibial intraneural ganglion cyst in a 10-year-old boy. Although extremely rare, intraneural ganglion cysts of the tibial nerve should be considered when a nonenhancing cystic structure with intra-articular extension is identified along the course of the nerve. This report also details the unsuccessful attempt at percutaneous treatment with US-guided cyst aspiration and steroid injection, an option recently reported as a viable alternative to open surgical resection.

This case report is of a symptomatic posterior-lateral elbow plica in a child who presented with elbow locking. MR images demonstrated thickening of a posterior-lateral plica between the radius and capitellum of the elbow. Surgery confirmed a thickened and inflamed posterior-lateral plica, which was resected with subsequent improvement of the child's symptoms. This case shows the clinical importance of identifying thickening of posterior-lateral plicae in children and suggesting the diagnosis of plica syndrome, an entity that has not been previously reported in children in the radiologic literature.

Objective: The clinical course of juvenile dermatomyositis (JDMS) is unpredictable. MRI is used to determine muscle biopsy site and to monitor disease activity. It is unknown whether soft-tissue features on MRI obtained at diagnosis correlate with clinical outcome. The purpose of our study is to determine whether initial MRI findings in the pelvis and thighs in children with JDMS can predict clinical disease course., Materials and Methods: Forty-five children (31 girls and 14 boys; median age, 6 years; range, 1-18 years) with clinically diagnosed biopsy-proven JDMS and at least 24 months of clinical follow-up were included. Clinical outcome was categorized as limited or chronic disease, according to the established Crowe clinical classification scheme. Pretreatment MRI examinations of the pelvis and thighs were evaluated for signal abnormalities of muscle and fascia and reticulated signal changes in subcutaneous fat; associations with clinical outcome were examined., Results: Twenty-two patients had limited disease and 23 had chronic disease. Signal intensity ranged from normal (n = 3) to floridly increased in all muscle compartments (n = 17). Muscle and fascial involvement were not associated with clinical outcome. Controlling for duration of symptoms, the adjusted odds of progressing to chronic disease were higher for patients with abnormal subcutaneous fat signal than for those with normal fat signal (odds ratio, 9.0; 95% CI, 1.5-53.5; p < 0.02)., Conclusion: MRI findings of muscle or fascia involvement do not predict clinical outcome in children with newly diagnosed JDMS. Abnormal subcutaneous fat signal appears to have a significant association with a more aggressive chronic disease course.

We report a case of primary bone lymphoma (PBL) in a 15-year-old girl assessed by MR imaging with diffusion-weighted imaging (DWI). DWI has been shown to help characterize the cellularity of solid tumors and this case correlates well with previous data.

Synovial diseases in children can be classified into normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts); noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), and infectious synovial proliferation, deposition disease, vascular malformations, malignancy (including metastasis) and intra-articular/periarticular cysts and cyst-like structures (ganglia). Familiarity with characteristic MR imaging findings of synovial diseases in children and young adults will enable a more confident diagnosis for earlier intervention and directed therapy. The first part of this paper will cover potential pathology of normal synovial structures as well as noninfectious synovial proliferation.

Synovium is the thin membranous lining of a joint. It produces synovial fluid, which lubricates and nourishes the cartilage and bone in the joint capsule. Synovial diseases in children can be classified as normal structures as potential sources of pathology (synovial folds: plicae, infrapatellar fat pad clefts), noninfectious synovial proliferation (juvenile idiopathic arthritis, hemophilic arthropathy, lipoma arborescens, synovial osteochondromatosis, pigmented villonodular synovitis, reactive synovitis), infectious synovial proliferation (pyogenic arthritis, tuberculous arthritis), deposition disease (gouty arthropathy), vascular malformation, malignancy (metastasis) and intra-/periarticular cysts and cyst-like structures. Other intra-articular neoplasms, such as intra-articular synovial sarcoma, can mimic synovial disease in children.

Background: The bare spot of the glenoid fossa is a normal cartilage defect seen frequently in adults. It has been used on arthroscopy as a landmark for the center of the glenoid fossa. There are no reports of this variant in children, but we have noted it on some pediatric clinical shoulder MRI studies., Objective: Our main purpose is to evaluate the incidence of the bare spot in children and define location and MRI features., Materials and Methods: Shoulder MRI studies (total 570) from 2004 to 2008 were reviewed. Children were divided into two age groups: group 1, 0-10 years (n = 200), group 2, 11-20 years (n = 370)., Results: A total of 12 bare spots (2.1%) were identified; all were seen in group 2. Eight (67%) were central and four were eccentric in the glenoid fossa. All showed a well-marginated focal cartilage defect containing hyperintense joint fluid or contrast agent. Three also had air., Conclusion: The bare spot is seen in children. The absence in children younger than 10 years and the low incidence in the second decade support the proposed acquired nature. Familiarity with this finding is important so as not to misinterpret it as a pathologic condition.

The liver is the largest organ in the abdomen taking up a relatively greater area in infants and young children. It is a unique organ with a dual blood supply and amazing regenerative capacity. The liver has a number of important functions with regard metabolism, detoxification, and immune function. The internal anatomy of this organ is orderly and highly structured around the basic functional unit--the hepatic lobule and portal triad. Numerous pathologic conditions can involve the liver. In this article, we will focus on etiologic, clinical, and cross-sectional imaging features of several childhood congenital and acquired disorders of one component of the portal triad--the biliary system.

Various congenital and acquired disorders can affect the upper extremity in pediatric and adolescent patients. MR imaging can provide unique anatomic and diagnostic information in the evaluation of many of these disorders, including inflammatory, infectious, neoplastic, and arthritic conditions. This article rounds out the issue on pediatric musculoskeletal MR imaging. It focuses on the evaluation of more common congenital disorders, and mainly sports-related injuries of the shoulder, elbow, and wrist in children. MR imaging can be more challenging in diagnosis of some of these disorders. Features of overuse injuries in skeletally immature athletes are a unifying theme throughout the article.

Background: The purpose of the present study was to determine if patient age, lesion size, lesion location, presenting knee symptoms, and sex predict the healing status after six months of a standard protocol of nonoperative treatment for stable juvenile osteochondritis dissecans of the knee., Methods: Forty-two skeletally immature patients (forty-seven knees) who presented with a stable osteochondritis dissecans lesion were included in the present study. All patients were managed with temporary immobilization followed by knee bracing and activity restriction. The primary outcome measure of progressive lesion reossification was determined from serial radiographs every six weeks, for up to six months of nonoperative treatment. A multivariable logistic regression model was used to determine potential predictors of healing status from the listed independent variables., Results: After six months of nonoperative treatment, sixteen (34%) of forty-seven stable lesions had failed to progress toward healing. The mean surface area (and standard deviation) of the lesions that showed progression toward healing (208.7 +/- 135.4 mm(2)) was significantly smaller than that of the lesions that failed to show progression toward healing (288.0 +/- 102.6 mm(2)) (p = 0.05). A logistic regression model that included patient age, normalized lesion size (relative to the femoral condyle), and presenting symptoms (giving-way, swelling, locking, or clicking) was predictive of healing status. Age was not a significant contributor to the predictive model (p = 0.25)., Conclusions: In two-thirds of immature patients, six months of nonoperative treatment that includes activity modification and immobilization results in progressive healing of stable osteochondritis dissecans lesions. Lesions with an increased size and associated swelling and/or mechanical symptoms at presentation are less likely to heal.

Objective: Patients operated on for anorectal malformations can experience technical complications related to the initial corrective surgery. Many of these complications may necessitate reoperation. Pelvic MRI is part of the evaluation to assess the position of the pulled-through bowel, the sphincter muscles, and the critical area of the posterior urethra. This article reviews the various pelvic MRI findings in these patients., Conclusion: Pelvic MRI is a valuable tool in the assessment of postoperative anorectal malformations that may necessitate additional surgery.

Objective: The objective of our study was to describe the MRI appearance of chronic repetitive stress injury of the iliac crest apophysis in adolescent athletes., Conclusion: Increased signal intensity on water-sensitive sequences and mild widening of the physis, often with adjacent bone marrow and muscle edema, are characteristic of chronic stress injury of the iliac apophysis in adolescent athletes who may present with hip, pelvic, or back pain.

In the mid 1990s, the fast spin-echo (FSE) and turbo spin-echo (TSE) T2-weighted (T2-W) sequences became available and are now widely accepted alternatives to conventional spin-echo sequences since they result in reduced acquisition times while maintaining tissue contrast. Since that time, there has been continued development of new sequences to further decrease acquisition times, minimize artifacts, and preserve lesion detection. The purpose of this pictorial essay is to qualitatively illustrate the newly available fast recovery (FR) FSE T2-W MR images of the abdomen compared with the images acquired using the routine FSE T2-W sequence in non-breath-hold studies in children.

We report a neonate with 4S neuroblastoma and MYCN amplification, but favorable Shimada histology, successfully treated with chemotherapy and 13-cis-retinoic acid without stem cell transplantation. MYCN amplification in neuroblastoma is usually associated with unfavorable Shimada histology; the presence of these features in infants with 4S disease confers a poor prognosis. A small number of infants with 4S neuroblastoma and MYCN amplification have favorable Shimada histology. In this subgroup of infants, histopathology may be equally important in predicting outcome.

Competitive athletics in school-aged children has become the norm rather than the exception. The increased repetitive stresses placed on the upper extremity in a wide variety of sports result in a host of injuries unique to the skeletally immature athlete. This article focuses on a discussion of the more common upper extremity injuries encountered in the child athlete and the role of radiography and MRI in diagnosis and management.

Tailgut cyst, or retrorectal cystic hamartoma, is a rare congenital lesion found in the presacral space. The lesion has been infrequently reported in the literature. We report the MRI findings of a tailgut cyst in a 2-year-old girl who presented with a sacral dimple and skin discoloration.

Objective: The purpose of this study was to describe the MRI appearance of accessory breast tissue that should be considered a diagnostic possibility in peripubertal or pubertal girls who present with an axillary mass along the course of the primitive milk streak., Conclusion: The MRI appearance of accessory breast tissue is of a mass discontinuous with-but with signal intensity and contrast enhancement characteristics similar to-normal breast parenchyma.

Objective: Dilute Hypaque Sodium is generally well accepted as an oral contrast agent for CT of pediatric patients who have experienced recent blunt abdominal trauma. However, Hypaque can cause complications. Using water as a substitute contrast agent eliminates these potential complications. The purpose of our study was to compare the performance of water with that of dilute Hypaque as an oral contrast agent. Our hypothesis was that we would find no significant difference in performance between the two agents in defining anatomic details of the hollow gastrointestinal tract., Materials and Methods: We performed a retrospective review of 74 CT scans obtained in infants and children who had received blunt abdominal trauma, scoring the quality of visualization of bowel structures, the presence of non-bowel-related findings, and the confidence level in making each assessment. The date range of the scans reviewed overlapped with the period in which the oral contrast material used for scanning such patients was switched from dilute Hypaque to water. Of the 74 CT scans that we reviewed, 53 were obtained with dilute Hypaque and 21 were obtained with water. The sex distribution between the two groups was compared using a chi-square test, whereas the mean age was compared using a two-sample two-sided Student's t test. A two-sample one-sided Student's t test of equivalence was used to analyze the data., Results: Sex distribution for the two groups of patients was not significantly different (69.81% of the group who received dilute Hypaque were boys; 68.18% of the group who received water were boys). Furthermore, the difference in the mean age for the two groups was not statistically significantly (dilute Hypaque group, 8.86 years; water group, 10.18 years). No statistically significant difference in performance of the contrast agents was found with respect to the detection of intraabdominal abnormality. As an oral contrast material, water performed as well as dilute Hypaque in facilitating visualization of all intraabdominal anatomic structures., Conclusion: In defining anatomic details of the hollow gastrointestinal tract, water is as effective as dilute Hypaque as an oral contrast agent for CT in the setting of acute blunt abdominal trauma in pediatric patients.

Lap belt restraints in motor vehicle collisions have been associated with a variety of injuries, mainly bowel and lumbar spine. Cephalad positioning of the belt over the intended position across the anterior superior iliac spines (which typically occurs in younger children) is thought to be responsible for the observed bowel injuries. We report two pediatric patients, both restrained by lap belts in high-speed collisions, who suffered iliac wing fractures in addition to bowel injuries. Unexplained free peritoneal fluid was the sole CT finding in one patient (a teenage girl) who had a delay in diagnosis of bowel perforation. These cases illustrate the high frequency of bowel injury in pediatric patients with iliac wing fractures associated with lap belt use.

Objective: Our purpose was to describe the use of MR imaging in the evaluation of the positions of the popliteal artery and peroneal nerve in children with popliteal pterygium syndrome for preoperative planning and to describe the typical appearance of popliteal pterygium on MR imaging., Conclusion: By depicting the popliteal artery and peroneal nerve either in normal positions or abnormally located immediately adjacent to the pterygium, MR imaging provides useful information for preoperative planning in children with popliteal pterygium syndrome. The MR appearance of a popliteal pterygium is that of a band of abnormal tissue extending from the ischium to the os calcis that has signal characteristics of fibrous tissue often attached to a belly of anomalous muscle.

Background: Although the accuracy of focused abdominal sonography for trauma (FAST) in adults has been demonstrated, results of this technique in children have been conflicting with few comparisons against computed tomography (CT), the imaging gold standard., Methods: A total of 160 hemodynamically stable pediatric trauma victims referred for abdominal CT initially underwent rapid screening sonography looking for free fluid. Both studies were interpreted in blinded fashion., Results: Forty-four of the 160 patients had an intraabdominal injury on CT, 24 (55%) of which had normal screening sonography. Fifteen of the 44 (34%) had no free fluid on either modality. Accuracy of sonography compared with CT was 76% with a negative predictive value 81%., Conclusions: Sonography for free fluid alone is not reliable to exclude blunt intraabdominal injury in hemodynamically stable children given the considerable percentage of injured patients without free fluid. J Pediatr Surg 36:565-569., (Copyright 2001 by W.B. Saunders Company.)

Adjustments of the standard helical CT protocols for adults can result in reduced radiation dose when imaging children. It is the radiologist's responsibility to critically evaluate the CT techniques used at their institution. Adjustments to CT protocols should be made to choose the appropriate mA and pitch when imaging children.

Purpose: To determine if pediatric splenic injury healing observed during ultrasonography (US) is related to the computed tomographic (CT) grade of injury severity, to review any delayed complications, and to formulate a grade-specific timetable for follow-up imaging., Materials and Methods: Sixty-eight children and adolescents with CT-documented blunt splenic injury underwent US at approximate 6-week intervals to document injury healing (normal parenchyma or linear echogenic "scar"). Medical records of those not followed up to complete healing were reviewed., Results: Forty-eight patients were followed up to complete injury healing: 14 of injury grade 1 (mean, 7 weeks; range, 4-12 weeks), 24 of injury grade 2 (mean, 9.5 weeks; range, 6-17 weeks), and 10 of injury grade 3 (mean, 16 weeks; range, 6-29 weeks). The difference in mean time to healing among all grades was significant (P < .02). Only two cysts were found; one decreased in size over time. No complications occurred in the 68 study patients., Conclusion: The time course to US-documented healing of blunt pediatric splenic injury is related to injury severity. This information can be used to tailor follow-up imaging and provide cost savings.

Objective: To determine how well MRI can detect tarsal coalition compared with CT, the current imaging standard., Materials and Methods: Coronal and axial CT and MRI were performed within 3 weeks of each other on 40 feet in 20 consecutive patients referred with symptoms of possible tarsal coalition. Scans were read independently in blinded fashion by different imagers. Coalitions were either complete (osseous) or incomplete (non-osseous). Results were compared with available surgical data and clinical follow-up., Results: Both modalities prospectively identified 15 coalitions (9 patients) and each missed 1 calcaneonavicular coalition. Twenty-three of the remaining 24 feet were negative for coalition on both CT and MRI. An atypical incomplete talocalcaneal coalition seen on CT was not identified prospectively on MRI., Conclusion: MRI is very good for detecting tarsal coalition and has a high rate of agreement with CT, the imaging "gold standard." When clinical suspicion for coalition is high, CT remains a more cost-effective diagnostic modality. If other causes for ankle pain are also entertained, MRI can be performed and provide nearly equivalent diagnostic accuracy for detecting tarsal coalition.

Objective: Our objective is to describe the clinical entity and MR imaging appearance of fat necrosis after trauma, a benign cause of palpable soft-tissue lesions in children. A related objective is to establish MR imaging criteria that can be used reliably to differentiate this entity from other more serious causes of soft-tissue masses., Conclusion: Fat necrosis after trauma is a common cause of palpable lumps in children and has a benign course on long-term follow-up. When characteristic MR imaging findings are seen, conservative therapy is appropriate.

Of medical and surgical emergencies in the pediatric abdomen, those involving the spleen are relatively less common than other abdominal organs, though equally important to recognize. A more sophisticated clinical understanding of the important role of the spleen in immunocompetence has developed in parallel with advancements in imaging. A healthy respect for the preservation of splenic tissue has emerged, altering traditional surgical management of splenic emergencies. Non-invasive imaging has come to play a vital role in depicting acute abnormalities and in determining the need for conservative, interventional, or surgical management.

Purpose: To review results from cross-sectional imaging studies performed to evaluate asymptomatic anterior chest wall lesions in children., Materials and Methods: All magnetic resonance (MR) images or computed tomographic (CT) scans of the chest obtained from 1989 to 1996 for evaluation of asymptomatic, palpable, focal, anterior chest wall lesions in otherwise healthy children were reviewed. Fifty-one children were considered for the study. Findings from 27 examinations in 27 children (13 underwent MR imaging, and 14 underwent CT) were included in the study. All children had normal radiographs of the region. Twenty-four patients did not meet the inclusion criteria and were excluded., Results: The cause of the lesion palpated at physical examination was identified in 26 of 27 patients: prominent anterior convex ribs in 10 patients; "tilted" sternum in six; prominent asymmetric costal cartilage in four; bifid rib in one; and well-defined, small (< 1-cm) subcutaneous nodule adjacent to costal cartilage in five. One examination demonstrated no abnormality. Of the 27 patients, none required treatment., Conclusion: All palpable, asymptomatic, anterior chest wall lesions were benign and usually related to normal variations in the bone or cartilage of the chest wall. The low yield of cross-sectional imaging performed for evaluation of these asymptomatic "bumps" should be considered when decisions are made with regard to imaging.

Objective: During the first year of life, the spleen undergoes histologic changes as the lymphoproliferative system matures. The purposes of this study were to describe the normal MR appearance of the spleen during infancy and early childhood and to correlate imaging findings with age-related histologic changes., Materials and Methods: The spleen was evaluated on 28 abdominal MR studies obtained during the first 23 months of life. Splenic signal intensity was compared to that of the liver. Selected autopsy specimens were compared with the imaging results., Results: The T2-weighted signal intensity of the spleen gradually increased from isointense to hypointense relative to the liver during the first week of life to moderately hyperintense to the liver by 8 months of age. T1-weighted splenic signal intensity gradually decreased. These findings corresponded to histological increases in white-pulp-red-pulp ratios., Conclusion: Before the lymphoid system completely matures, the T2-weighted signal intensity of the normal neonatal spleen appears decreased compared with the moderately hyperintense splenic signal seen in older children and adults. This finding should not be mistaken for disease.

Objective: To evaluate the safety and efficacy of orally administered perflubron for bowel recognition on MR imaging in a pediatric population., Materials and Methods: A multicenter trial evaluated 39 pediatric subjects before and after ingestion of perflubron with T1-, proton-density, and T2-weighted sequences through the abdomen and/or pelvis. Post-contrast images were compared with pre-contrast images. Safety was evaluated through assessment of adverse events, clinical laboratory parameters, and vital signs., Results: With regard to efficacy analysis, improvement in the percent of bowel darkened was observed for 85 % of the subjects on T1-weighted images and for 95 % of the subjects on proton-density and T2-weighted images. For images of the abdominal region, the percent of bowel darkened was improved for 90-92 % of the subjects across pulse sequences. Improvement rates for the images of the pelvic region ranged from 71 % to 100 %. For at least 75 % of the subjects, proton-density and T2-weighted images of the body and tail of the pancreas, left lobe of the liver, mesenteric fat, and pathological tissue were improved relative to predosing images. Twenty-three percent of the subjects experienced some adverse effects, most of which were minor and related to the digestive system. Clinical laboratory and vital sign evaluations revealed no trends associated with the administration of perflubron., Conclusion: Perflubron is a relatively safe and effective gastrointestinal MR contrast agent in the pediatric population.

Objective: The purpose of this study was to evaluate the efficacy of MR imaging in predicting the pathologic diagnosis of soft-tissue masses, both neoplastic and nonneoplastic, and in distinguishing benign from malignant lesions., Materials and Methods: The imaging features of 225 soft-tissue tumors (179 benign, 46 malignant) in 222 patients were analyzed. Univariate analysis of multiple individual imaging features was done, along with stepwise logistic regression analysis of combinations of imaging features, to determine how useful these are for predicting malignancy or benignity. A subjective (group consensus) analysis of each case was done prospectively, and each tumor was placed into one of three diagnostic categories: (1) benign, diagnostic of a specific entity; (2) nonspecific, most likely benign; or (3) nonspecific, most likely malignant. Results were compared with the final diagnosis established by pathologic examination (n = 184) or imaging/clinical data (n = 41)., Results: By quantitative analysis, no single imaging feature or combination of features could reliably be used to distinguish benign from malignant lesions. For the subjective analysis, a correct and specific benign diagnosis could be made on the basis of MR imaging findings in 100 (44%) of the 225 tumors. For the entire cohort, the sensitivity was 78%, the specificity was 89%, the positive predictive value was 65%, and the negative predictive value was 94% for a malignant diagnosis. When the diagnostic benign tumors were excluded, the specificity and negative predictive value decreased to 76% and 86%, respectively, whereas the sensitivity and positive predictive value remained the same., Conclusion: Many benign soft-tissue masses can be correctly and confidently diagnosed with MR imaging. The prevalence of benign lesions among soft-tissue masses accounts for the relatively high specificity and negative predictive value that can be achieved with MR imaging for tissue characterization. However, the accuracy of MR imaging declines when these characteristic benign tumors are excluded from analysis. A significant percentage of malignant lesions may appear deceptively "benign" with the currently used criteria. For lesions whose imaging appearance is nonspecific, MR imaging is not reliable for distinguishing benign from malignant tumors, and these lesions warrant biopsy in most cases.