Pre-treatment MRI of leukaemia and lymphoma in children: are there differences in marrow replacement patterns on T1-weighted images?

OBJECTIVES: To investigate the prevalence and distribution of specific marrow patterns on pre-treatment magnetic resonance imaging (MRI) examinations in children with leukaemia and lymphoma and with respect to the anatomic location. MATERIALS AND METHODS: This retrospective IRB-approved and HIPAA-compliant study included children with leukaemia or lymphoma who underwent pre-treatment MRI examinations over 18 years (between 1 January 1995 and 31 August 2013). Two radiologists blinded to the clinical diagnosis reviewed each study to determine the presence or absence of abnormal marrow signal and, when present, sub-categorised the pattern into diffuse, patchy, or focal abnormal marrow. Chi-square and Fisher's exact tests were used to compare marrow patterns between leukaemia and lymphoma. RESULTS: The study included 50 children (32 males and 18 females; mean age 9.5 ± 5.3 years) with 54 MRI examinations (27 leukaemia and 27 lymphoma) that included 26 spine and 28 non-spine studies. Marrow replacement was present on 43 (80%) studies, significantly more common with leukaemia than with lymphoma (p = 0.039). The diffuse replacement pattern was significantly more common with leukaemia when compared to lymphoma (p < 0.001) and the focal pattern was only observed with lymphoma. In the spine, the diffuse pattern was observed with lymphoma (3/14, 21%). All patients with leukaemia and MRI outside of the spine showed marrow involvement. CONCLUSION: Marrow replacement is common on MRI from children with leukaemia and lymphoma. A diffuse pattern was significantly associated with leukaemia on studies outside of the spine and a focal pattern was only observed with lymphoma, independently of the anatomic location. KEY POINTS: • Bone marrow replacement on pre-treatment MRI examinations in children with leukaemia and lymphoma was observed in 93% (25/27) and 67% (18/27), respectively. • Diffuse pattern of marrow replacement was significantly more common in leukaemia even though this pattern was also observed with lymphoma on the spine MRI studies. • Focal pattern of marrow replacement was present only with lymphoma and not with leukaemia regardless of the anatomic location.

Lateral Meniscus Posterior Root Injury: MRI Findings in Children With Anterior Cruciate Ligament Tear.

BACKGROUND. Undiagnosed and unrepaired root tears are increasingly recognized as a preventable cause of accelerated osteoarthritis. Preoperative MRI findings of lateral meniscus posterior root tears in children with concomitant anterior cruciate ligament (ACL) injury are not well described. OBJECTIVE. The purpose of this study was to investigate the performance of preoperative MRI for identifying concomitant lateral meniscus posterior root injuries in pediatric patients with ACL tears with arthroscopy as the reference standard. METHODS. Consecutively registered children who underwent MRI within 90 days before arthroscopic primary ACL reconstruction between March 2017 and December 2019 were included. Two radiologists assessed MRI examinations for direct signs involving the root proper and for findings associated with lateral meniscus posterior root tears. Kappa coefficients for MRI findings were computed. Findings in patients with root tears and intact roots were compared by independent-samples t test, Mann-Whitney U test, chi-square test, Fisher exact test, and multivariable logistic regression analysis. RESULTS. At arthroscopy, 39 children (18 boys, 21 girls; mean age, 15.2 ± 1.4 years) had lateral meniscus posterior root tears; 51 (22 boys, 29 girls; mean age, 15.7 ± 1.8 years) had intact roots. Kappa coefficients ranged from 0.65 to 0.92, aside from tears involving the entheseal segment (κ = 0.55) or popliteomeniscal fascicles (κ = 0.45). MRI findings that were predictors of arthroscopically diagnosed root tear (p < .05) were lateral meniscus root tear in any segment (odds ratio [OR], 16.8; 95% CI, 5.6-50.1), degeneration in any segment (OR, 3.9; 95% CI, 1.6-9.6), coronal cleft sign (OR, 5.7; 95% CI, 2.0-16.7), sagittal ghost sign (OR, 4.8; 95% CI, 1.2-19.1), and axial radial defect sign (OR, 7.1; 95% CI, 2.4-20.5). Tear involving any segment of the root proper had the highest PPV, 82%, with 79% NPV. The coronal cleft, sagittal ghost, and axial radial defect signs had specificities of 88%, 94%, and 88% but sensitivities of 44%, 23%, and 49%. The only significant independent predictor on preoperative MRI was root tear in any segment (OR, 15.8; 95% CI, 2.7-137.5; p = .003). CONCLUSION. Among MRI findings evaluated for preoperative diagnosis of lateral meniscus posterior root tear, tear involving any segment of the root proper had the strongest performance; associated findings had high specificity but low sensitivity. CLINICAL IMPACT. Accurate identification of lateral meniscus posterior root tears on preoperative MRI can aid in operative planning and reduce treatment delay.

Age-dependent changes in pediatric scaphoid fracture pattern on radiographs.

OBJECTIVE: To systematically investigate age-dependent changes in scaphoid fracture prevalence and fracture patterns on radiographs in children under 15 years of age. METHODS AND MATERIALS: This retrospective study included children with scaphoid fractures, who underwent radiographic examinations between May 1, 2009, and August 31, 2019. Blinded to outcome, all radiographs were reviewed to determine fracture visibility on initial radiographs; to characterize fracture location (distal corner, distal, mid, and proximal body) and orientation (horizontal oblique, transverse, and vertical oblique); and to identify the presence or absence of gap, displacement, and concomitant fractures. Demographic information and information on weight and height were collected. Mann-Whitney U, Kruskal-Wallis rank sum, chi-square, and post hoc tests were used to investigate associations between age, fracture characteristics, and BMI percentile. RESULTS: The study included 180 children (134 boys and 46 girls; 12.3 ± 1.4 years) with 59 (33%) distal corner, 42 (23%) distal, 76 (42%) mid, and 3 (2%) proximal body fractures. Younger children were more likely to present with distal corner and distal body fractures while older children with mid and proximal body fractures (p = 0.035). No association was found between age and fracture visibility (p = 0.246), fracture orientation (p = 0.752), presence of gap (p = 0.130), displacement (p = 0.403), or concomitant fractures (p = 0.588). Younger children with scaphoid fractures were more likely to be obese (n = 117; p = 0.038). CONCLUSION: Scaphoid fractures of the distal corner and distal body were significantly more common in younger children, who are more likely to be obese.