Selective Use of Pulmonary Vasodilators in Patients with Fontan Physiology.

Background: Fontan-associated liver disease is a well-known sequela following the Fontan procedure for patients living with single-ventricle heart disease. Pulmonary vasodilators, such as phosphodiesterase type 5 inhibitors, have emerged as a potential therapeutic option for lowering central venous pressures by reducing pulmonary vascular resistance. Method: We performed a single-center retrospective review of Fontan patients who were placed on pulmonary vasodilator therapy with prehemodynamic and posthemodynamic, MR elastography, and histologic assessments. Results: A total of 125 patients with Fontan circulation underwent surveillance with cardiac catheterization during the review period. Fifty-three (42%) patients who did not have increased end-diastolic pressures at the time of cardiac catheterization were started on phosphodiesterase type 5 inhibitor therapy. Nine patients (17%) underwent posttherapy follow-up catheterization. The mean Fontan pressure decreased from 15.4 ± 3.3 mmHg to 13.3 ± 2.5 mmHg (p=0.026), after initiation of pulmonary vasodilatory therapy. There was no change in end-diastolic pressure, transpulmonary gradient, wedge pressure, pulmonary vascular resistance, cardiac index, or saturation. Eleven patients (21%) underwent pretherapy MR elastography testing with posttherapy follow-up MR elastography. We found no improvement in liver stiffness score following the application of pulmonary vasodilators. Three patients underwent pretherapy and posttherapy liver biopsies, with variable histological changes observed within the hepatic parenchyma. Conclusions: These data demonstrate indeterminate results for the selective use of pulmonary vasodilators but highlight the need for large prospective randomized control trials of pulmonary vasodilator therapies to fully assess the benefit of such therapies in Fontan-associated liver disease.

Magnetic resonance imaging appearance of breaststroker's knee.

Breaststroker's knee is an overuse syndrome resulting from similar repetitive movements in competitive swimmers that has been described in the orthopedic literature. The typical symptoms are medial knee pain with tenderness to palpation at the tibial collateral ligament or inferomedial patella. Despite these localizing symptoms on clinical exam, arthroscopic studies have failed to demonstrate a specific structural abnormality corresponding to this syndrome, although some have reported thickened medial synovial plica, medial-predominant synovitis or patellofemoral cartilage loss in association knee pain with breaststroke swimmers. We present a case of medial knee pain in a young breaststroke swimmer with magnetic resonance imaging (MRI) findings of marrow edema in the anterior aspect of the medial femoral condyle. To our knowledge, this is the first reported case of MRI findings in breaststroker's knee .

The Curse of the All-Star Team: A Single-Season Prospective Shoulder MRI Study of Little League Baseball Players.

BACKGROUND: Throwing guidelines have been implemented in Little League baseball in an attempt to minimize injuries in young baseball players. We hypothesized that playing pitcher or catcher and increased innings played during the season would result in dominant shoulder magnetic resonance imaging (MRI) abnormalities. METHODS: A prospective evaluation of Little League players aged 10 to 12 years was performed. Players recruited before the start of the season underwent bilateral preseason and dominant shoulder postseason MRI, physical examination, and questionnaires addressing their playing history and arm pain. Innings played, player position, pitch counts, and all-star team selection were recorded. RESULTS: In total, 23 players were enrolled. The majority (19/23, 82.6%) were right-handed and 16 of 23 (69.6%) played at least 10 innings as pitcher or catcher. Sixteen were selected for the all-star team. Fourteen players (60.9%) had positive dominant shoulder MRI findings not present in their nondominant shoulder. Eight players (34.8%) had new or worsening postseason MRI findings. Thirteen players (81.3%) selected to the all-star team had abnormal MRI findings whereas only one (14.3%) player not selected as an all-star had MRI abnormalities (P=0.005). Year-round play (P=0.016), innings pitched (P=0.046), innings catcher (P=0.039), and number of pitches (P=0.033) were associated with any postseason MRI abnormality, but not for new or worsening MRI changes. Single sport athletes and players playing for multiple teams were significantly more likely to have abnormal MRI findings (P=0.043 and 0.040, respectively) when compared with multisport athletes playing on a single team. CONCLUSIONS: MRI abnormalities involving the dominant shoulder are common in Little League baseball players and often develop or worsen during the season. Contrary to our hypothesis, MRI abnormalities were not associated with player position and pitch counts. Instead, they were most closely associated with year round play, single sports participation, and all-star team selection. The increased demands required for all-star selection comes at a price to the young athlete as the majority of players selected for this honor had abnormal MRI findings in their throwing shoulder while few non all-stars demonstrated such pathology. LEVEL OF EVIDENCE: Level II.

A framework for the radiologic diagnosis of skeletal dysplasias and syndromes as revealed by molecular genetics.

This article simplifies the radiologic diagnosis of skeletal dysplasia by first presenting an ordered approach for analysis of standard radiographs done for skeletal dysplasias. With that foundation, a more detailed discussion of three separate families of skeletal disorders follows. Similarities among dysplasia group members are discussed to provide a certain connectedness among dysplasias. The paper also elucidates the scientific basis behind the radiographic findings so that previously purely descriptive terms have the weight of understanding behind them.

Imaging of Pediatric Growth Plate Disturbances.

The growth plates, or physes, are visible on virtually all images obtained in skeletally immature children. The proper function of these growth plates depends on an intricate balance between chondrocyte proliferation, which requires nourishment from the epiphyseal vessels, and chondrocyte death, which requires the integrity of the metaphyseal vessels. Therefore, injury to the growth plate (ie, direct insult) or vascular compromise on either side of the growth plate (ie, indirect insult) can cause growth plate dysfunction. Direct growth plate insults occur most commonly with Salter-Harris fractures, and injuries that allow the transphyseal communication of vessels are at a higher risk for subsequent transphyseal bone bridge formation. Indirect insults lead to different sequelae that are based on whether the epiphyseal blood supply or metaphyseal blood supply is compromised. Epiphyseal osteonecrosis can result in slowed longitudinal bone growth, with possible growth plate closure, and is often accompanied by an abnormal secondary ossification center. In contrast, the disruption of metaphyseal blood supply alters endochondral ossification and allows the persistence of chondrocytes within the metaphysis, which appear as focal or diffuse growth plate widening. Imaging remains critical for detecting acute injuries and identifying subsequent growth disturbances. Depending on the imaging findings and patient factors, these growth disturbances may be amenable to conservative or surgical treatment. Therefore, an understanding of the anatomy and physiologic features of the normal growth plate and the associated pathophysiologic conditions can increase diagnostic accuracy, enable radiologists to anticipate future growth disturbances, and ensure optimal imaging, with the ultimate goal of timely and appropriate intervention. ©RSNA, 2017.

A Structural and Mechanism-Based Perspective Toward Understanding Pediatric and Adult Sports Injuries.

OBJECTIVE: The purpose of this article is to compare the injury patterns in skeletally mature patients versus skeletally immature patients to better understand the factors that cause the specific injury appearance. The physis as the essential factor in the injury manifestation will be examined. CONCLUSION: The physis and immature chondroosseous junctions operate as the weak links in the immature skeleton and are the deciding factors in the pattern of injury, even though the injury mechanisms are identical to those in adults.

Diagnostic shortcomings of magnetic resonance arthrography to evaluate partial rotator cuff tears in adolescents.

BACKGROUND: Recent evidence suggests an increase in the incidence of partial articular-sided rotator cuff tears in adolescent athletes, but the accuracy of diagnostic studies has not been previously assessed in this cohort. This study was performed to assess the ability of magnetic resonance imaging with arthrography (MRIa) to diagnose partial rotator cuff (PRC) pathology in the adolescent age group. METHODS: All patients under the age of 19 years who underwent shoulder arthroscopy, between August 2008 and August 2010, were grouped based on the presence of a PRC tear diagnosed by either MRIa or arthroscopy. The control cohort included children without evidence of an intraoperative PRC. Surgical findings were then correlated with the preoperative MRIa findings and the accuracy of MRIa reading. Interclass coefficient was then determined for the MRIa reviewers. RESULTS: Thirty-one of 89 adolescents (mean age, 15.9 y; 36% girls and 64% boys) who underwent arthroscopic shoulder surgery were found to have radiographic or arthroscopic evidence of a PRC injury. There were 17 boys and 14 girls in the PRC group, with a mean age of 15.6 years. The PRC injuries involved either the supraspinatus tendon, infraspinatus tendon, or both. MRIa was 44% sensitive and 87% specific, with a positive predictive value of 64% and a negative predictive value of 74% with arthroscopic findings used as the gold standard. The ICC between reviewers was κ=0.57, with an absolute agreement of 84%. CONCLUSIONS: The overall diagnostic accuracy of the MRIa with regard to adolescent PRC injuries was 72%. MRIa was found to be specific, but not sensitive for the diagnosis of this pathology. The high false-negative rate seen in this adolescent cohort indicates that a PRC injury may be present even with a negative MRIa. Therefore, if clinical suspicion indicates a PRC injury, then the treating physician should consider management for rotator cuff pathology despite negative MRIa findings. LEVEL OF EVIDENCE: Level III--retrospective cohort study.

Feasibility of ultrashort TE (UTE) imaging of children at 1.5 T.

Ultrashort TE (UTE) is a relatively new MRI technique that allows for the visualization of tissue structures with short T2 components that show little or no signal on all conventional MR imaging sequences. This technique, to the best of our knowledge, has been described only in adults and uses a half excitation pulse and radial k-space data acquisition to produce echo times of less than 100 microseconds with no need for additional hardware modifications. We describe the feasibility of using a 2-D UTE sequence in vivo on a routine 1.5 T clinical MR scanner to depict various musculoskeletal structures in children.

The Buford Complex Redefined: A Pathologic Morphology in Sheep's Clothing.

Background: Considered a normal anatomic variant, the Buford complex has not been studied in children. Hypothesis: A Buford complex is not a normal anatomic variant and would, therefore, be present at a lower rate than that seen in the adult population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Measurements were recorded from magnetic resonance imaging performed over 13 years in children aged ≤11 years for various pathologies unrelated to glenohumeral instability. Interrater reliability was determined to identify Buford complexes, sublabral foramens and tears, and normal shoulders via 16 preadolescent and adolescent patients with confirmed arthroscopic correlation. The Buford complex and labral foramen rates were then compared with a published rate in adults using a binomial probability test. Results: A total of 122 children (62 girls; mean age, 6.4 years [age range, 2 months-10.9 years]) were evaluated. Interrater reliability was 0.846 (95% CI, 0.56-1) to identify anterosuperior labral variants. The expected sublabral foramen count was 23 children, but only 1 was identified (P < .001). The expected Buford complex count was 8 children, but none could be identified (P < .001). Conclusion: The absence of Buford complexes and the significant reduction in sublabral foramen abundance in younger children suggest that these anatomic variants are more likely to be developmental than congenital. The distinct possibility that these previously considered normal variants are truly pathologic findings cannot be ignored. Evidence of a Buford complex could potentially signify an underlying, long-term shoulder instability issue to the treating provider that warrants further investigation or management.

A systematic method for evaluation of pediatric sports injuries of the elbow.

We present a compartmentalized approach to sports injuries of the pediatric elbow. Lateral, medial and posterior injuries are considered separately under the unifying umbrella of the common forces projected on the elbow during sports activities and the effect on the separate growth centers and physes of the elbow.

Radiologic analysis of femoral acetabular impingement: from radiography to MRI.

Femoral acetabular impingement is a set of morphologic abnormalities that are considered to be a major cause of degenerative disease in the hip joint. Early changes are already present in adolescence when it is the pediatric radiologist who must assess current damage with the aim of averting progression to more severe and debilitating osteoarthritis. A multimodality approach is used for diagnosis, that includes conventional radiography and CT to assess the osseous structures. MR arthrography is the primary advanced imaging modality for assessment of morphologic changes as well as injuries of the labrum and articular cartilage. Details of radiologic imaging are offered to guide the radiologist and provide an avenue for the accurate description of the osseous and articular alterations and injury.

Multiplanar CT assessment of femoral head displacement in slipped capital femoral epiphysis.

BACKGROUND: With recent changing approaches to the management of slipped capital femoral epiphysis (SCFE), the accurate radiographic assessment of maximum extent of displacement is crucial for planning surgical treatment. OBJECTIVE: To determine what plane best represents the maximum SCFE displacement as quantified by the head-neck angle difference (HNAD), whether HNAD can quantitatively differentiate the SCFE cohort from the normal cohort, based on CT, and how Southwick slip angle (SSA) compares to HNAD. MATERIALS AND METHODS: We reviewed 19 children with SCFE (23 affected hips) with preoperative CT scans and 27 age- and sex-matched children undergoing abdominal CT for non-orthopedic problems. Head-neck angle (HNA), the angle between the femoral epiphysis and the neck axis, was measured in three planes on each hip and the HNAD (affected - unaffected hip) was determined. SSA was measured on radiographs. RESULTS: The coronal HNAD (mean 8.7°) was less than both the axial-oblique (mean 30.7°) and sagittal (mean 37.4°) HNADs, which were also greater than the HNADs of the normal cohort. Grouping HNAD measurements by SSA severity classification did not consistently distinguish between SCFE severity levels. CONCLUSION: Axial-oblique and sagittal planes best represent the maximum SCFE displacement while biplanar radiograph may underestimate the extent of the displacement, thereby potentially altering the management between in situ pinning and capital realignment.

MR evaluation of femoral neck version and tibial torsion.

Abnormalities of femoral neck version have been associated with a number of hip abnormalities in children, including slipped capital femoral epiphysis, proximal femoral focal deficiency, coxa vara, a deep acetabulum and, rarely, developmental dysplasia of the hip. Orthopedic surgeons also are interested in quantifying the femoral neck anteversion or retroversion in children especially to plan derotational osteotomies. Historically, the angle of femoral version and tibial torsion has been measured with the use of radiography and later by CT. Both methods carry with them the risks associated with ionizing radiation. Techniques that utilize MR are used less often because of the associated lengthy imaging times. This article describes a technique using MRI to determine femoral neck version and tibial torsion with total scan times of approximately 10 min.

The radiographic approach to child abuse.

BACKGROUND: Osseous injuries are a major facet of child abuse and in most patients radiographic imaging plays a major role in diagnosis. While some injuries are typically produced as a result of excessive and inappropriate force other injuries are nonspecific in terms of their causation, but become suspicious when the history provided by the caretakers is inconsistent with the type of injury produced. QUESTIONS/PURPOSES: I detail the radiographic imaging of the more characteristic of the highly specific injuries, discuss the major issues that relate to some moderate- or low-specificity injuries, and describe several diseases that mimic abuse. METHODS: A review of the current and recent literature focused on the radiographic imaging of child abuse was performed by searching the National Library of Medicine database at pubmed.gov. Keywords used included: radiology, fracture, child abuse, and/or nonaccidental trauma. RESULTS: Injuries that are highly specific for the diagnosis of abuse include metaphyseal corner fractures, posteromedial rib fractures, and sternal, scapular, and spinous process fractures. Lesions of moderate specificity include, among other injuries, multiple fractures of various ages and epiphyseal separations. Long-bone fractures and clavicular fractures, while common, are of low specificity. In addition to the appropriate accurate diagnosis of these injuries, several diseases and syndromes may mimic abuse due to the similarity in the radiographic picture. CONCLUSIONS: Stratification of fractures sustained in child abuse according to specificity and an understanding of the several diseases that mimic abuse are helpful in the accurate diagnosis of child abuse. LEVEL OF EVIDENCE: Level V, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

MRI for the evaluation of pectus excavatum.

Pectus excavatum, the most common congenital deformity of the anterior chest wall, is both a cosmetic and functional abnormality. The degree of abnormal chest wall deformity determines its functional effect, particularly its cardiac and pulmonary impact. Although CT scanning is the most widely used cross-sectional imaging technique used to measure the Haller index, the radiation exposure is reason to seek other alternatives. At our institution, we have introduced a rapid MRI technique for this purpose, which utilizes a single-axial 2-D FIESTA acquisition.

Ultrashort echo time MR imaging of osteochondral junction of the knee at 3 T: identification of anatomic structures contributing to signal intensity.

PURPOSE: To image cartilage-bone interfaces in naturally occurring and experimentally prepared human cartilage-bone specimens at 3 T by using ultrashort echo time (TE) (UTE) and conventional pulse sequences to (a) determine the appearance of the signal intensity patterns and (b) identify the structures contributing to signal intensity on the UTE MR images. MATERIALS AND METHODS: This study was exempted by the institutional review board, and informed consent was not required. Five cadaveric (mean age, 86 years +/- 4) patellae were imaged by using proton density-weighted fat-suppressed (repetition time msec/TE msec, 2300/34), T1-weighted (700/10), and UTE (300/0.008, 6.6, with or without dual-inversion preparations at inversion time 1 = 135 msec and inversion time 2 = 95 msec) sequences. The UTE images were compared with proton density-weighted fat-suppressed and T1-weighted images and were evaluated by two radiologists. To identify the sources of signal on the UTE images, samples including specific combinations of tissues (uncalcified cartilage [UCC] only, calcified cartilage [CC] and subchondral bone [bone] [CC/bone], bone only; and UCC, CC, and bone [UCC/CC/bone]) were prepared and imaged by using the UTE sequence. RESULTS: On the UTE MR images, all patellar sections exhibited a high-intensity linear signal near the osteochondral junction, which was not visible on protein density-weighted fat-suppressed or T1-weighted images. In some sections, focal regions of thickened or diminished signal intensity were also found. In the prepared samples, UCC only, CC/bone, and UCC/CC/bone samples exhibited high signal intensity on the UTE images, whereas bone-only samples did not. CONCLUSION: These results show that the high signal intensity on UTE images of human articular joints originates from the CC and the deepest layer of the UCC, without a definite contribution from subchondral bone. UTE sequences may provide a way of evaluating abnormalities at or near the osteochondral junction. (c) RSNA, 2010.

The periosteum: what is it, where is it, and what mimics it in its absence?

Nearly every bone in the body is invested in periosteum. The periosteum is in some ways poorly understood and has been a subject of controversy and debate. This tissue has a major role in bone growth and bone repair and has an impact on the blood supply of bone as well as skeletal muscle. Despite the importance of the periosteum is has received little attention in the literature in recent years.

Periosteal stripping in high ankle sprains: An association with osteonecrosis.

OBJECTIVE: We present a series of 20 cases of a sleeve-type injury of the distal tibia characterized by traumatic periosteal stripping caused by a high ankle sprain. We characterize the magnetic resonance imaging findings associated with this injury and highlight its association with distal tibial osteonecrosis. MATERIALS AND METHODS: We collected 20 cases of high ankle sprains with periosteal stripping of the distal tibia through teaching files and a search through our PACS database. We recorded the presence and pattern of syndesmotic ligamentous injury and the presence or absence of syndesmotic widening in patients with periosteal stripping. The presence or absence of associated fractures and osteonecrosis was noted and characterized by location. RESULTS: The most commonly torn ligament was the anterior inferior tibiofibular ligament. 25% (5/20) of the patients in our series developed osteonecrosis. Osteonecrosis developed as early as 3-4 weeks following the initial injury. Of the patients with osteonecrosis, 40% (2/5) had fractures of the posterior malleolus. All patients with osteonecrosis had widening of the syndesmosis. Two of the five patients with osteonecrosis were in the pediatric age group. CONCLUSION: In contrast to conventional syndesmotic and interosseous ligamentous tearing, high ankle injuries with tibial periosteal stripping may result in avulsion of the extra-osseous vasculature supplied by the periosteum, leading to osteonecrosis. This pattern of injury has not been emphasized in the literature. Our findings underscore the importance of the integrity of the periosteum for maintaining adequate vascularity of the distal tibia.

Progressive Elbow Magnetic Resonance Imaging Abnormalities in Little League Baseball Players Are Common: A 3-Year Longitudinal Evaluation.

BACKGROUND: Prior studies have revealed magnetic resonance imaging (MRI) evidence of elbow pathology in single-season evaluation of competitive youth baseball players. The natural history of these findings and risk factors for progression have not been reported. PURPOSE: To characterize the natural history of bilateral elbow MRI findings in a 3-year longitudinal study and to correlate abnormalities with prior MRI findings, throwing history, playing status, and physical examination. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A prospective study of Little League players aged 12 to 15 years was performed. All players had preseason and postseason bilateral elbow MRI performed 3 years before this study. Players underwent repeat bilateral elbow MRI, physical examination, and detailed assessment of throwing history, playing status, and arm pain. Imaging was read by a blinded musculoskeletal radiologist and compared with prior MR images to assess for progression or resolution of previously identified pathology. RESULTS: All 26 players who participated in the previous single-season study returned for a 3-year assessment. At the completion of the study, 15 players (58%) had dominant arm MRI pathology. Eighty percent (12/15 players) of MRI findings were new or progressive lesions. Players with postseason MRI pathology at the beginning of the study were more likely to have MRI pathology at the 3-year follow-up than players with previously normal postseason MRI (P < .05), although 6 of the 14 players (43%) with previously normal MRI developed new pathology. Year-round play was a significant predictor of tenderness to elbow palpation (P = .027) and positive MRI findings at 3 years (P = .047). At the 3-year follow-up, 7 players (27%) reported having throwing elbow pain and 3 had required casting. Additionally, differences were noted in the dominant arm's internal and external rotation in those that continued to play baseball (P < .05). CONCLUSION: Dominant elbow MRI abnormalities are common in competitive Little League Baseball players. Year-round play imparts significant risk for progression of MRI pathology and physical examination abnormalities.