MDCT assessment of tracheomalacia in symptomatic infants with mediastinal aortic vascular anomalies: preliminary technical experience.

BACKGROUND: Mediastinal aortic vascular anomalies are relatively common causes of extrinsic central airway narrowing in infants with respiratory symptoms. Surgical correction of mediastinal aortic vascular anomalies alone might not adequately treat airway symptoms if extrinsic narrowing is accompanied by intrinsic tracheomalacia (TM), a condition that escapes detection on routine end-inspiratory imaging. Paired inspiratory-expiratory multidetector CT (MDCT) has the potential to facilitate early diagnosis and timely management of TM in symptomatic infants with mediastinal aortic vascular anomalies. OBJECTIVE: To assess the technical feasibility of paired inspiratory-expiratory MDCT for evaluating TM among symptomatic infants with mediastinal aortic vascular anomalies. MATERIALS AND METHODS: The study group consisted of five consecutive symptomatic infants (four male, one female; mean age 4.1 months, age range 2 weeks to 6 months) with mediastinal aortic vascular anomalies who were referred for paired inspiratory-expiratory MDCT during a 22-month period. CT angiography was concurrently performed during the end-inspiration phase of the study. Two pediatric radiologists in consensus reviewed all CT images in a randomized and blinded fashion. The end-inspiration and end-expiration CT images were reviewed for the presence and severity of tracheal narrowing. TM was defined as > or =50% reduction in tracheal cross-sectional luminal area between end-inspiration and end-expiration. The presence of TM was compared to the bronchoscopy results when available (n = 4). RESULTS: Paired inspiratory-expiratory MDCT was technically successful in all five patients. Mediastinal aortic vascular anomalies included a right aortic arch with an aberrant left subclavian artery (n = 2), innominate artery compression (n = 2), and a left aortic arch with an aberrant right subclavian artery (n = 1). Three (60%) of the five patients demonstrated focal TM at the level of mediastinal aortic vascular anomalies. The CT results were concordant with the results of bronchoscopy in all patients who underwent bronchoscopy (n = 4). CONCLUSION: Paired inspiratory-expiratory MDCT is technically feasible for evaluating TM in symptomatic infants with mediastinal aortic vascular anomalies and has the potential to facilitate prompt diagnosis and treatment.

MDCT evaluation of the prevalence of tracheomalacia in children with mediastinal aortic vascular anomalies.

OBJECTIVE: The purpose of this study is to determine the prevalence of tracheomalacia (TM) associated with different types of mediastinal aortic vascular anomalies in symptomatic children using paired inspiratory-expiratory multidetector computed tomography (MDCT). MATERIALS AND METHODS: The study group consisted of 15 consecutive symptomatic pediatric patients (12 males/3 females; mean age of 4.4 y; age range of 2 wk to 16 y) with mediastinal aortic vascular anomalies, who were referred for paired inspiratory-expiratory MDCT during a 35-month time period. Computed tomography (CT) angiography was also concurrently performed during the end-inspiration phase of the study. Two radiologists in consensus reviewed all CT images in a randomized and blinded fashion. End-inspiration and end-expiration CT images were reviewed for the presence and severity of tracheal narrowing and the type of mediastinal aortic vascular anomaly involved. TM was defined as > or =50% reduction in tracheal cross-sectional luminal area between end-inspiration and end-expiration. The presence of TM was correlated with the type of mediastinal aortic vascular anomaly and compared with the bronchoscopy results when available (n=9). RESULTS: Mediastinal aortic vascular anomalies included innominate artery compression (IAC) (n=6), a right aortic arch with an aberrant left subclavian artery (n=5), double aortic arch (n=3), and a left aortic arch with an aberrant right subclavian artery (n=1). Eight of 15 (53.3%) patients demonstrated TM. TM was seen in all 6 patients (100%) with IAC, 1 of 3 (33.3%) patients with double aortic arch, and 1 of 5 (20%) patients with a right aortic arch with an aberrant left subclavian artery. CT results were concordant with the results of bronchoscopy in all patients who underwent this procedure (n=9). CONCLUSIONS: Symptomatic pediatric patients with mediastinal aortic vascular anomalies have a relatively high prevalence of TM, especially those with IAC. Paired inspiratory-expiratory MDCT should be considered part of the routine preoperative evaluation of TM in symptomatic children with IAC and also has the potential to play a role in evaluating patients with other mediastinal aortic vascular anomalies.

MRI of knee osteonecrosis in children with leukemia and lymphoma: Part 1, observer agreement.

OBJECTIVE: The aim of this study was to determine whether a new MRI-based staging system for osteonecrosis of the knee in pediatric patients could be used with an acceptable level of intra- and interobserver agreement. MATERIALS AND METHODS: We conducted a retrospective analysis of MRI studies of the knee performed in a single institution between April 1994 and July 2003. Knee osteonecrosis was identified in 168 children with a primary diagnosis of hematologic malignancy. This substantial number prompted us to design a staging system for use with pediatric patients. To assess interobserver reliability of two primary observers in using the system, they reviewed and interpreted the same 36 imaging studies of randomly chosen patients. For the assessment of intraobserver reproducibility, each observer rereviewed 16 studies. A senior observer coded potential causes of disagreement between the primary observers. RESULTS: Interobserver agreement was substantial: the kappa value was 0.66 (95% confidence interval [CI], 0.58-0.75) in locations where the observers had to record only the presence or absence of a lesion, and the weighted kappa value was 0.65 (95% CI, 0.59-0.72) in locations where they had to classify the extent of involvement. The presence of marrow edema, punctate foci of altered signal, and mottled marrow changes was associated with a higher level of disagreement between the primary observers. CONCLUSION: Our proposed classification system, developed specifically for use with MRI, was used with substantial intra- and interobserver agreement. We think its use can contribute to a standardized approach to the interpretation of MRI findings in pediatric osteonecrosis of the knee.

MRI of knee osteonecrosis in children with leukemia and lymphoma: Part 2, clinical and imaging patterns.

OBJECTIVE: This aim of this study was to explore the relationship between MRI findings and clinical symptoms of knee osteonecrosis in children and to determine the significance of this relationship. Such information is important for early diagnosis of this frequent complication and for choosing an appropriate treatment strategy. MATERIALS AND METHODS: Osteonecrotic lesion size and location were determined in a retrospective analysis of MR images of the knee obtained in our institution during the past 10 years. Association between MRI findings and clinical symptoms expressed by the knee scores was tested for a subgroup of our patient population who had clinical evaluation of the knees in the orthopedic clinic within 6 weeks of their MRI studies. RESULTS: In 80% of patients, osteonecrosis was bilateral. Lesions were distributed as follows: femur and tibia, 66% of the knees; femur alone, 26%; and tibia alone, 8%. Clinical symptoms of knee osteonecrosis were associated with lesions involving the articular surface of the distal femur, large lesions, and involvement of any part of the tibia. MR images showed milder osteonecrosis in patients who were less than 10 years old at the time of primary diagnosis. CONCLUSION: Osteonecrosis affecting the knees of children treated for leukemia and lymphoma is mostly asymptomatic. Children who are 10 years old or older have signs of more advanced osteonecrosis. Clinical symptoms often lag MRI presentation and may develop late in the course of the disease. Routine MRI evaluation is recommended for timely diagnosis of treatment-induced osteonecrosis.