RASopathies for Radiologists.

RASopathies are a heterogeneous group of genetic syndromes caused by germline mutations in a group of genes that encode components or regulators of the Ras/mitogen-activated protein kinase (MAPK) signaling pathway. RASopathies include neurofibromatosis type 1, Legius syndrome, Noonan syndrome, Costello syndrome, cardiofaciocutaneous syndrome, central conducting lymphatic anomaly, and capillary malformation-arteriovenous malformation syndrome. These disorders are grouped together as RASopathies based on our current understanding of the Ras/MAPK pathway. Abnormal activation of the Ras/MAPK pathway plays a major role in development of RASopathies. The individual disorders of RASopathies are rare, but collectively they are the most common genetic condition (one in 1000 newborns). Activation or dysregulation of the common Ras/MAPK pathway gives rise to overlapping clinical features of RASopathies, involving the cardiovascular, lymphatic, musculoskeletal, cutaneous, and central nervous systems. At the same time, there is much phenotypic variability in this group of disorders. Benign and malignant tumors are associated with certain disorders. Recently, many institutions have established multidisciplinary RASopathy clinics to address unique therapeutic challenges for patients with RASopathies. Medications developed for Ras/MAPK pathway-related cancer treatment may also control the clinical symptoms due to an abnormal Ras/MAPK pathway in RASopathies. Therefore, radiologists need to be aware of the concept of RASopathies to participate in multidisciplinary care. As with the clinical manifestations, imaging features of RASopathies are overlapping and at the same time diverse. As an introduction to the concept of RASopathies, the authors present major representative RASopathies, with emphasis on their imaging similarities and differences. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

A threshold volume of 10 ml is suggested for detecting articular cartilage defects in equine carpal joints using CT arthrography: Ex vivo pilot study.

Computed tomographic arthrography (CTA) has been described as a method for detecting articular cartilage defects in equine carpal joints; however, published studies on the effects of contrast volume for lesion detection are currently lacking. The purpose of this prospective, experimental, pilot study was to determine a threshold volume of iodinated contrast for CTA of the antebrachiocarpal (ABC) and middle carpal (MC) joints for detection of articular cartilage surface defects. Articular cartilage defects were iatrogenically created in the surfaces of the ABC and MC joints of 20 equine cadaver limbs using arthroscopy. Unaltered articular surfaces within some joints acted as controls. Joints were imaged precontrast using multidetector CT. The ABC and MC joints were injected with a 150 mg iodine/ml nonionic contrast medium, in 5 ml increments from 5 to 50 ml per joint with CT performed subsequent to each increment. Cartilage defects were measured grossly using a caliper. Detection (qualitative) and measurement (quantitative) of the defects were independently performed by two board-certified radiologists using medical imaging software. At each volume of contrast, the interrater reliability for gross examination and the two observers in the detection of a defect was calculated (Gwet's AC1). Logistic mixed-effects models of selected volumes, 0, 5, 10, 15, and 50 ml, demonstrated that at 10 ml contrast and above, no statistically significant difference between either observer and gross examination for defect detection was identified for either joint. Findings supported using a dose of 10 ml for 150 mg iodine/ml concentration contrast media when performing CTA of equine carpal joints.

The pediatric stomach - masses and mass-like pathology.

Diagnostic imaging of pediatric gastric masses often provides a challenge for the practicing radiologist. Radiologists should be aware of this relatively unusual pathology, particularly in cross-sectional imaging findings. We will review pediatric gastric masses and mass-like lesions, focusing on neoplastic and inflammatory etiologies.

Imaging features of pathologically proven pediatric splenic masses.

Splenic masses present a diagnostic challenge to radiologists and clinicians alike, with a relative paucity of data correlating radiologic findings to pathological diagnosis in the pediatric population. To illustrate splenic mass imaging findings and approximate lesion prevalence, we retrospectively reviewed all splenectomies and splenic biopsies for splenic masses at a single academic pediatric hospital over a 10-year period in patients 18 years and younger. A total of 31 splenic masses were analyzed. Lesion prevalence, pathology and imaging features associated with sampled splenic masses are described. The lesions encountered include benign splenic cysts (9), vascular anomalies (7), hamartoma (3), leukemia/lymphoma (3), granulomata (3) and metastasis (2). We also identified single cases of angiosarcoma, splenic cord capillary hemangioma, congestive hemorrhage, and benign smooth muscle neoplasm.

Standing CT of the equine head: Reducing radiation dose maintains image quality.

Multiple published studies involving computed tomographic (CT) examinations of the equine head utilise a wide range of mAs parameters for image acquisition. This prospective, experimental study assessed the effects of lowering mAs during CT image acquisition on image quality and scatter radiation on 10 cadaver equine heads. Each head was scanned three times at 300, 225, and 150 mAs, with all other scanning parameters remaining constant between series. An anthropomorphic phantom was positioned adjacent to each equine head during image acquisition, mimicking a human bystander, with an ionization chamber attached to the phantom at eye level. Each series was reconstructed using filtered back projection, using medium (H30) and high (H80) frequency reconstruction algorithms. Quantitative image quality assessment was performed by calculating signal to noise ratio (SNR) and contrast to noise ratio (CNR). Two qualitative image quality assessments were performed independently by three blinded board certified veterinary radiologists with a 4 week interval, using a visual grade analysis model adapted from peer reviewed medical literature. Ionization chamber measurements, calculated volume CT dose index (CTDIvol), and dose-length product (DLP) were recorded. Halving radiation dose during image acquisition from 300 to 150mAs resulted in comparable image quality between series. There was a statistically significant and linear relationship between mAs and scatter radiation to the bystander; halving mAs during image acquisition resulted in halving of scatter radiation. Results of this cadaveric study support the use of lower mAs settings during standing CT examinations of the equine head.

The Distended Fetal Hypopharynx: A Sensitive and Novel Sign for the Prenatal Diagnosis of Esophageal Atresia.

BACKGROUND/PURPOSE: Although advances have been made in the prenatal diagnosis of esophageal atresia (EA), most neonates are not identified until after birth. The distended hypopharynx (DHP) has been suggested as a novel prenatal sign for EA. We assess its diagnostic accuracy and predictive value on ultrasound (US) and magnetic resonance imaging (MRI), both alone and in combination with the esophageal pouch (EP) and secondary signs of EA (polyhydramnios and a small or absent fetal stomach). METHODS: We retrospectively reviewed fetal US and MRI reports and medical records of 88 pregnant women evaluated for possible EA from 2000 to 2016. Seventy-five had postnatal follow-up that confirmed or disproved the diagnosis of EA and were included in our analysis. RESULTS: Seventy-five women had 107 study visits (range 1-4). DHP and/or EP were seen on US and/or MRI in 36% of patients, and 78% of those patients had EA. DHP was 24% more sensitive for EA than EP, while EP was 30% more specific. After 28weeks of gestation, DHP had a predictive accuracy for EA of 0.929 (P=0.001). CONCLUSIONS: DHP is a sensitive additional prenatal sign of EA. More accurate diagnosis of EA allows for improved counseling regarding delivery, postnatal evaluation, and surgical correction. TYPE OF STUDY: Diagnostic. LEVEL OF EVIDENCE: Level II.

Contrast enhanced ultrasound for the evaluation of blunt pediatric abdominal trauma.

INTRODUCTION: Blunt abdominal trauma is a common problem in children. Computed tomography (CT) is the gold standard for imaging in pediatric blunt abdominal trauma, however up to 50% of CTs are normal and CT carries a risk of radiation-induced cancer. Contrast enhanced ultrasound (CEUS) may allow accurate detection of abdominal organ injuries while eliminating exposure to ionizing radiation. METHODS: Children aged 7-18years with a CT-diagnosed abdominal solid organ injury underwent grayscale/power Doppler ultrasound (conventional US) and CEUS within 48h of injury. Two blinded radiologists underwent a brief training in CEUS and then interpreted the CEUS images without patient interaction. Conventional US and CEUS images were compared to CT for the presence of injury and, if present, the injury grade. Patients were monitored for contrast-related adverse reactions. RESULTS: Twenty one injured organs were identified by CT in eighteen children. Conventional US identified the injuries with a sensitivity of 45.2%, which increased to 85.7% using CEUS. The specificity of conventional US was 96.4% and increased to 98.6% using CEUS. The positive predictive value increased from 79.2% to 94.7% and the negative predictive value from 85.3% to 95.8%. Two patients had injuries that were missed by both radiologists on CEUS. In a 100kg, 17year old female, a grade III liver injury was not seen by either radiologist on CEUS. Her accompanying grade I kidney injury was not seen by one of the radiologist on CEUS. The second patient, a 16year old female, had a grade III splenic injury that was missed by both radiologists on CEUS. She also had an adjacent grade II kidney injury that was seen by both. Injuries, when noted, were graded within 1 grade of CT 33/35 times with CEUS. There were no adverse reactions to the contrast. CONCLUSION: CEUS is a promising imaging modality that can detect most abdominal solid organ injuries in children while eliminating exposure to ionizing radiation. A multicenter trial is warranted before widespread use can be recommended. LEVEL OF EVIDENCE: Level II; Diagnostic Prospective Study.

Percent predicted lung volume changes on fetal magnetic resonance imaging throughout gestation in congenital diaphragmatic hernia.

PURPOSE: Percent predicted lung volume (PPLV)<15% on fetal MRI predicts high-risk CDH. Potential changes in PPLV throughout gestation and impact on risk stratification are unknown. We reviewed CDH patients with serial fetal MRIs to follow PPLV and determine correlation with postnatal outcomes. METHODS: CDH patients with serial fetal MRIs from 2005 to 2015 were included. We recorded prenatal MRI gestational age (GA) and PPLV, postnatal ECMO use, and survival. Data were analyzed by logistic regression and Fisher's exact test. RESULTS: 57 patients had 127 fetal MRI studies. PPLV decreased from mean 25.4% to 19.6% between GA 22.1 and 32.6weeks. A steeper decline in PPLV, regardless of final PPLV, was independently predictive of higher ECMO use (p=0.046) and death (p=0.045). All patients with first PPLV<15% remained high-risk with poor outcomes. Of those with first PPLV>15%, 31% dropped below 15%, having similar ECMO use as the high-risk cohort, but trending toward greater survival (p=0.09). Those with first and final PPLV>15% had significantly less ECMO use (p=0.015) and greater survival (p<0.001) than the high-risk cohort. CONCLUSIONS: On average, PPLV decreases throughout gestation in fetuses with CDH. Serial MRI is recommended for those with initial PPLV>15%, as clinical outcomes tend to mirror the lowest PPLV. TYPE OF STUDY: Treatment study LEVEL OF EVIDENCE: III.

Can the Onset of Type 2 Diabetes Be Delayed by a Group-Based Lifestyle Intervention in Women with Prediabetes following Gestational Diabetes Mellitus (GDM)? Findings from a Randomized Control Mixed Methods Trial.

OBJECTIVE: To evaluate a 12-week group-based lifestyle intervention programme for women with prediabetes following gestational diabetes (GDM). DESIGN: A two-group, mixed methods randomized controlled trial in which 50 women with a history of GDM and abnormal glucose tolerance postpartum were randomly assigned to intervention (n = 24) or wait control (n = 26) and postintervention qualitative interviews with participants. MAIN OUTCOME MEASURES: Modifiable biochemical, anthropometric, behavioural, and psychosocial risk factors associated with the development of type 2 diabetes. The primary outcome variable was the change in fasting plasma glucose (FPG) from study entry to one-year follow-up. RESULTS: At one-year follow-up, the intervention group showed significant improvements over the wait control group on stress, diet self-efficacy, and quality of life. There was no evidence of an effect of the intervention on measures of biochemistry or anthropometry; the effect on one health behaviour, diet adherence, was close to significance. CONCLUSIONS: Prevention programmes must tackle the barriers to participation faced by this population; home-based interventions should be investigated. Strategies for promoting long-term health self-management need to be developed and tested.

Ventricular remodelling post-bariatric surgery: is the type of surgery relevant? A prospective study with 3D speckle tracking.

AIMS: The aim of the study was to examine ventricular remodelling in patients free of cardiac risk factors, before, and 6 months post-bariatric surgery with the new imaging modality of three-dimensional (3D) strain and the comparison of two surgical techniques: sleeve gastrectomy vs. gastric bypass. METHODS AND RESULTS: Fifty-two consecutive patients referred to the Bariatric Services of Imperial College NHS Trust were examined with conventional 2D and 3D strain echocardiography, prior to and 6 months after bariatric surgery. They were all free from cardiac disease. The study cohort's mean age was 44.2 ± 8.7 years and body mass index of 42.4 ± 4.6 g/m(2) prior to surgery. Eighteen patients (34.6%) underwent laparoscopic sleeve gastrectomy, and 34 laparoscopic gastric bypass. On 3D speckle tracking, there was significant reverse remodelling post-bariatric surgery [left ventricular (LV) ejection fraction (EF): pre-surgery: 59 ± 8% vs. post-surgery: 67 ± 7%, P < 0.001 and right ventricular (RV) EF: pre-surgery: 60 ± 9% vs. post-surgery: 68 ± 8.2%, P = 0.0001]. Furthermore, there was significant regression of mass (LV mass: pre-surgery: 111 ± 23.5 g vs. post-surgery: 92.8 ± 15.5 g and RV mass: pre-surgery: 95.2 ± 19.8 vs. post-surgery: 67.3 ± 16.3, P < 0.001). RV and LV global strain improved 6 months post-bariatric surgery: global RV strain: pre-surgery -11.7 ± 4 vs. post-surgery -17.52 ± 3.7, P < 0.001; global LV strain: pre-surgery: -20.2 ± 1.7 vs. post-surgery: -26.5 ± 1.86, P < 0.001. Sleeve gastrectomy and gastric bypass had comparable effects. CONCLUSION: Bariatric surgery has an important effect in reverse LV and RV remodelling and it substantially improves RV longitudinal strain.

Reasons for participation and non-participation in a diabetes prevention trial among women with prior gestational diabetes mellitus (GDM).

BACKGROUND: Gestational diabetes mellitus (GDM) is a risk factor for the development of type 2 diabetes. Lifestyle intervention can prevent progression to type 2 diabetes in high risk populations. We designed a randomised controlled trial (RCT) to evaluate the effectiveness of an established lifestyle intervention compared to standard care for delaying diabetes onset in European women with recent GDM. Recruitment into the RCT was more challenging than anticipated with only 89 of 410 (22%) women agreeing to participate. This paper identifies factors that could enhance participation of the target population in future interventions. METHODS: We hypothesised that women who agreed to participate would have higher diabetes risk profiles than those who declined, and secondly that it would be possible to predict participation on the bases of those risk factors. To test our hypothesis, we identified the subset of women for whom we had comprehensive data on diabetes risks factors 3-5 years following GDM, reducing the sample to 43 participants and 73 decliners. We considered established diabetes risk factors: smoking, daily fruit and vegetable intake, participation in exercise, family history of diabetes, glucose values and BMI scores on post-partum re-screens, use of insulin during pregnancy, and age at delivery. We also analysed narrative data from 156 decliners to further understand barriers to and facilitators of participation. RESULTS: Two factors differentiated participants and decliners: age at delivery (with women older than 34 years being more likely to participate) and insulin use during pregnancy (with women requiring the use of insulin in pregnancy less likely to participate). Binary logistic regression confirmed that insulin use negatively affected the odds of participation. The most significant barriers to participation included the accessibility, affordability and practicality of the intervention. CONCLUSIONS: Women with recent GDM face multiple barriers to lifestyle change. Intervention designers should consider: (i) the practicalities of participation for this population, (ii) research designs that capitalise on motivational differences between participants, (iii) alleviating concerns about long-term diabetes management. We hope this work will support future researchers in developing interventions that are more relevant, effective and successful in recruiting the desired population. TRIAL REGISTRATION: Current Controlled Trials ISRCTN41202110.

Translating guidelines to practice: findings from a multidisciplinary preventive cardiology programme in the west of Ireland.

AIMS: The aim of this observational, descriptive study is to evaluate the impact of an intensive, evidence-based preventive cardiology programme on medical and lifestyle risk factors in patients at high risk of developing cardiovascular disease (CVD). METHODS: Increased CVD risk patients and their family members/partners were invited to attend a 16-week programme consisting of a professional multidisciplinary lifestyle intervention, with appropriate risk factor and therapeutic management in a community setting. Smoking, dietary habits, physical activity levels, waist circumference and body mass index, and medical risk factors were measured at initial assessment, at end of programme, and at 1-year follow up. RESULTS: Adherence to the programme was high, with 375 (87.2%) participants and 181 (84.6%) partners having completed the programme, with 1-year data being obtained from 235 (93.6%) patients and 107 (90.7%) partners. There were statistically significant improvements in both lifestyle (body mass index, waist circumference, physical activity, Mediterranean diet score, fish, fruit, and vegetable consumption, smoking cessation rates), psychosocial (anxiety and depression scales and quality of life indices), and medical risk factors (blood pressure, lipid and glycaemic targets) between baseline and end of programme, with these improvements being sustained at 1-year follow up. CONCLUSIONS: These findings demonstrate how a holistic model of CVD prevention can improve cardiovascular risk factors by achieving healthier lifestyles and optimal medical management.

Multiple duplication cysts diagnosed prenatally: case report and review of the literature.

Enteric duplication cysts (EDC) are typically solitary lesions that occur throughout the alimentary tract. Postnatal diagnosis is often prompted when complications occur from bleeding, obstruction, or infection. We present a case of multiple EDC diagnosed prenatally, managed with prenatal and neonatal follow-up and resection in infancy. Prenatal detection allowed for optimal management prior to the development of symptoms or complications.

Safety of intra-articular use of atelocollagen for enhanced tissue repair.

Collagen is an important biomaterial in intra-articular tissue engineering, but there are unanswered questions about its safety. We hypothesize that the addition of type-I-collagen for primary repair of the Anterior Cruciate Ligament (ACL) might result in a local and systemic reaction in a porcine model after 15 weeks as demonstrated by joint effusion, synovial thickening, elevated intraarticular and systemic leukocyte counts. Further, this reaction might be aggravated by the addition of a platelet concentrate. Eighteen porcine ACLs were transected and repaired with either sutures (n=6), a collagen sponge (n=6), or a collagen-platelet-composite (CPC; n=6). Twelve intact contralateral knees served as controls (n=12). No significant synovial thickening or joint effusion was seen in the collagen-treated knees. Synovial fluid leukocyte counts showed no significant differences between surgically treated and intact knees, and no differences were seen in leukocyte counts of the peripheral blood. The addition of a platelet concentrate to the knee joint resulted in lower serum levels of IL-1ß, but serum levels of TNF-α were not significantly different between groups. In conclusion, the presence of collagen, with or without added platelets, did not increase the local or systemic inflammatory reactions following surgery, suggesting that Type I collagen is safe to use in the knee joint.

ASPIRE-2-PREVENT: a survey of lifestyle, risk factor management and cardioprotective medication in patients with coronary heart disease and people at high risk of developing cardiovascular disease in the UK.

OBJECTIVE: To determine in patients with coronary heart disease (CHD) and people at high risk of developing cardiovascular disease (CVD) whether the Joint British Societies' guidelines on CVD prevention (JBS2) are followed in everyday clinical practice. DESIGN: A cross-sectional survey was undertaken of medical records and patient interviews and examinations at least 6 months after the recruiting event or diagnosis using standardised instruments and a central laboratory for measurement of lipids and glucose. SETTINGS: The ASPIRE-2-PREVENT survey was undertaken in 19 randomly selected hospitals and 19 randomly selected general practices in 12 geographical regions in England, Northern Ireland, Wales and Scotland. PATIENTS: In hospitals, 1474 consecutive patients with CHD were identified and 676 (25.6% women) were interviewed. In general practice, 943 people at high CVD risk were identified and 446 (46.5% women) were interviewed. RESULTS: The prevalence of risk factors in patients with CHD and high-risk individuals was, respectively: smoking 14.1%, 13.3%; obesity 38%, 50.2%; not reaching physical activity target 83.3%, 85.4%; blood pressure ≥130/80 mm Hg (patients with CHD and self-reported diabetes) or ≥140/85 mm Hg (high-risk individuals) 46.9%, 51.3%; total cholesterol ≥4 mmol/l 52.6%, 78.7%; and diabetes 17.8%, 43.8%. CONCLUSIONS: The potential among patients with CHD and individuals at high risk of developing CVD in the UK to achieve the JBS2 lifestyle and risk factor targets is considerable. CVD prevention needs a comprehensive multidisciplinary approach, addressing all aspects of lifestyle and risk factor management. The challenge is to engage and motivate cardiologists, physicians and other health professionals to routinely practice high quality preventive cardiology in a healthcare system which must invest in prevention.

Fetal brain volumetry through MRI volumetric reconstruction and segmentation.

PURPOSE: Fetal MRI volumetry is a useful technique but it is limited by a dependency upon motion-free scans, tedious manual segmentation, and spatial inaccuracy due to thick-slice scans. An image processing pipeline that addresses these limitations was developed and tested. MATERIALS AND METHODS: The principal sequences acquired in fetal MRI clinical practice are multiple orthogonal single-shot fast spin echo scans. State-of-the-art image processing techniques were used for inter-slice motion correction and super-resolution reconstruction of high-resolution volumetric images from these scans. The reconstructed volume images were processed with intensity non-uniformity correction and the fetal brain extracted by using supervised automated segmentation. RESULTS: Reconstruction, segmentation and volumetry of the fetal brains for a cohort of twenty-five clinically acquired fetal MRI scans was done. Performance metrics for volume reconstruction, segmentation and volumetry were determined by comparing to manual tracings in five randomly chosen cases. Finally, analysis of the fetal brain and parenchymal volumes was performed based on the gestational age of the fetuses. CONCLUSION: The image processing pipeline developed in this study enables volume rendering and accurate fetal brain volumetry by addressing the limitations of current volumetry techniques, which include dependency on motion-free scans, manual segmentation, and inaccurate thick-slice interpolation.

Fetal diagnosis of penoscrotal transposition associated with perineal lipoma in one twin.

Perineal lipoma is a rare condition which is commonly associated with scrotal anomalies and may be diagnosed as ambiguous genitalia. We report on a baby with penoscrotal transposition (PST) consisting of bifid scrotum and hypospadias with chordee associated with perineal lipoma. The affected baby was one twin of an IVF pregnancy referred to our center for ambiguous genitalia by fetal ultrasound. Examination of the uterus revealed a dichorionic, diamniotic twin pregnancy. Fetal ultrasound and MRI in our center revealed an exophytic perineal mass, which likely represented a lipoma, separate from the abnormally appearing phallus and scrotum (hypospadias with chordee and a bifid scrotum). This likely fell into the PST spectrum. There were no additional abnormalities in the other structures and no structural abnormality of co-twin was detected. Fetal growth of both twins was appropriate for gestational age. Babies were born at term and the findings of the affected twin correlated with the fetal diagnoses. While some reports show PSTs are associated with multiple anomalies, in this case no additional anomalies were identified. Perineal lipomas are commonly associated with scrotal abnormalities and anorectal malformations. It is hypothesized that these anomalies develop because of the perineal lipoma. MRI combined with ultrasound clearly defined the anomaly prenatally and allowed for accurate prenatal counseling and coordination of postnatal care.

Femoral head deformation and repair following induction of ischemic necrosis: a histologic and magnetic resonance imaging study in the piglet.

BACKGROUND: Ischemic necrosis of the femoral head can be induced surgically in the piglet. We used this model to assess femoral head deformation and repair in vivo by sequential magnetic resonance imaging and by correlating end-stage findings with histologic assessments. METHODS: Ischemic necrosis of the femoral head was induced in ten three-week-old piglets by tying a silk ligature around the base of the femoral neck (intracapsular) and cutting the ligamentum teres. We used magnetic resonance imaging with the piglets under general anesthesia to study the hips at forty-eight hours and at one, two, four, and eight weeks. Measurements on magnetic resonance images in the midcoronal plane of the involved and control sides at each time documented the femoral head height, femoral head width, superior surface cartilage height, and femoral neck-shaft angle. Histologic assessments were done at the time of killing. RESULTS: Complete ischemia of the femoral head was identified in all involved femora by magnetic resonance imaging at forty-eight hours. Revascularization began at the periphery of the femoral head as early as one week and was underway in all by two weeks. At eight weeks, magnetic resonance imaging and histologic analysis showed deformation of the femoral head and variable tissue deposition. Tissue responses included (1) vascularized fibroblastic ingrowth with tissue resorption and cartilage, intramembranous bone, and mixed fibro-osseous or fibro-cartilaginous tissue synthesis and (2) resumption of endochondral bone growth. At eight weeks, the mean femoral head measurements (and standard error of the mean) for the control compared with the ligated femora were 10.4 +/- 0.4 and 4.8 +/- 0.4 mm, respectively, for height; 26.7 +/- 0.8 and 31.2 +/- 0.8 mm for diameter; 1.1 +/- 0.1 and 2.3 +/- 0.1 mm for cartilage thickness; and 151 degrees +/- 2 degrees and 135 degrees +/- 2 degrees for the femoral neck-shaft angle. Repeated-measures mixed-model analysis of variance revealed highly significant effects of ligation in each parameter (p < 0.0001). CONCLUSIONS: Magnetic resonance imaging allows for the assessment of individual hips at sequential time periods to follow deformation and repair. There was a variable tissue response, and histologic assessment at the time of killing was shown to correlate with the evolving and varying magnetic resonance imaging signal intensities. Femoral head height on the ischemic side from one week onward was always less than the initial control value and continually decreased with time, indicating collapse as well as slowed growth. Increased femoral head width occurred relatively late (four to eight weeks), indicating cartilage model overgrowth concentrated at the periphery.

Post-closed reduction perfusion magnetic resonance imaging as a predictor of avascular necrosis in developmental hip dysplasia: a preliminary report.

INTRODUCTION: Avascular necrosis (AVN) of the femoral head remains a major complication in the treatment of developmental dysplasia of the hip (DDH) in infants. We performed a retrospective analysis to look at the predictive ability of postclosed reduction contrast-enhanced magnetic resonance imaging (MRI) for AVN after closed reduction in DDH. METHODS: Twenty-eight hips in 27 infants (aged 1-11 months) with idiopathic hip dislocations who had failed brace treatment underwent closed reduction +/- adductor tenotomy and spica cast application under general anesthesia. Magnetic resonance imaging of the hips after intravenous gadolinium contrast injection for evaluation of epiphyseal perfusion was obtained immediately after cast application. Patients were followed with serial radiographs for a minimum of 1 year after closed reduction. Presence of AVN was determined by the presence of any one of the 5 Salter criteria by 2 readers. Magnetic resonance imaging was graded as normal, asymmetric enhancement, focal decreased enhancement, or global decreased enhancement by 2 radiologists. RESULTS: Six (21%) of 28 hips showed evidence of clinically significant AVN on follow-up radiographs. Fifty percent of the hips with AVN, but only 2 of 22 hips without AVN, showed a global decreased MRI enhancement (P < 0.05, Fisher exact test). Multivariate logistic regression indicated that a global decreased enhancement was associated with a significantly higher risk of developing AVN (P < 0.01), independently of age at reduction (P = 0.02) and abduction angle. CONCLUSIONS: In addition to accurate anatomical assessment of a closed reduction in DDH, gadolinium-enhanced MRI provides information about femoral head perfusion that may be predictive for future AVN. At present, it is premature to use the perfusion information for routine clinical use. However, it opens the door to studies looking at repositioning or alternative reduction methods that may reduce the risk of AVN in this higher risk group.