MRI paving the way to diagnosis of acute lymphoblastic leukemia in children and adolescents – a retrospective observational study
摘要
Prompt diagnosis of childhood acute lymphoblastic leukemia (ALL) remains a clinical challenge, particularly in children presenting with normal blood counts and musculoskeletal symptoms. With the increasing use of magnetic resonance imaging (MRI) in evaluating such complaints, bone marrow signal alterations may be detected before hematologic abnormalities appear. Previous studies have described characteristic MRI patterns in leukemia, suggesting potential for earlier recognition. This study aims to clarify the role of MRI in the diagnostic pathway of pediatric ALL and to define radiological findings that should prompt bone marrow examination. We retrospectively reviewed all patients diagnosed with ALL at our institution between 2006 and 2024 and included those who underwent MRI prior to diagnosis. Clinical data were collected, and all MRI studies were re-evaluated by an experienced pediatric radiologist.
ResultsTwenty pediatric patients with ALL were included. Due to differing MRI protocols, the cohort was divided into two groups: one group (n = 17) underwent musculoskeletal imaging and one group (n = 3) underwent imaging of the trunk. Overall, MRI-detected bone marrow signal alterations contributed to diagnosis in 20 of 424 (4.7%) newly diagnosed pediatric ALL cases. More than one-third of patients (7/20; 35%) had a completely normal complete blood count (CBC) at presentation. Persistent bone pain was the leading symptom, preceding imaging in 18/20 cases. The mean time from symptom onset to MRI was 20.8 days (range 1–65), while the mean time from MRI to diagnosis was 18.4 days (range 0–180). In the musculoskeletal scans, all patients showed bone marrow signal alterations, predominantly T1-weighted (T1w) hypointensity (17/17) and proton-density-weighted (PDw) or T2-weighted short tau inversion recovery (T2w-STIR) hyperintensity (16/17). In the trunk scans, diffusion-weighted imaging revealed high DWI signal with low ADC values (3/3), and T2-weighted images demonstrated focal lesions (3/3).
ConclusionMRI plays an important role in the diagnostic pathway of pediatric ALL, especially in patients with persistent musculoskeletal pain and normal blood counts. In our cohort, MRI examinations could initiate a rapid diagnostic process leading to ALL confirmation. Diffuse T1w hypointensity and diffusion restriction emerged as key imaging findings. A normal CBC should therefore not delay urgent oncologic assessment when the clinical presentation and MRI pattern are suspicious for leukemia.