Added value of Diffusion Weighted Image and Apparent diffusion coefficient mapping in differentiation between bone marrow neoplastic infiltration and non-neoplastic complication in hematologic malignancies

Rezumat

BACKGROUND: Hematological malignancies, including lymphomas, leukemia, and multiple myeloma, commonly infiltrate the bone marrow (BM). Commonly observed post-treatment complications that affect BM include osteonecrosis, osteomyelitis, ischemic infarction, pathological fractures, and avascular necrosis. These complications frequently occur secondary to chemotherapy, radiotherapy, and high doses of corticosteroids. Magnetic resonance imaging (MRI) is considered the gold-standard imaging modality for the assessment of BM due to its high contrast resolution without radiation exposure. In hematological malignancies, distinguishing benign from malignant bone marrow changes remains notoriously chellenging. Diffusion-weighted images (DWI) are highly sensitive sequences for assessing the mobility of free water molecules reflecting micro-vascular changes. It may provide a promising alternative sequence devoid of contrast. The study aimed to evaluate the over-added value of DWI and apparent diffusion coefficient (ADC) in differentiation between BM neoplastic infiltration and benign complication in hematologic malignancies. Methods: The retrospective study included 150 patients with pathologically proven hematological malignancy with bone marrow lesions. All patients underwent a 1.5 T MRI standard protocol with a diffusion-weighted sequence. The gold standard criteria were used to assess pathological neoplastic infiltration. In addition, a 2-year follow-up was conducted for cases of non-neoplastic infiltration where there were single or tiny suspicious lesions that could not be biopsied due to inaccessibility or unsuitability. An MRI follow-up should be conducted within a period of 3 to 6 months to confirm the final diagnosis. Results: Among the 150 patients, 63 (42%) were diagnosed with leukemia, while 72 (48%) were diagnosed with multiple myeloma. Out of the total, 15 patients (10%) were diagnosed with lymphoma, 90 patients (60.0%) had neoplastic infiltrations, and 60 patients (40.0%) experienced non-neoplastic complications. The qualitative DWI showed a restricted bright signal in (93.3%) of the neoplastic infiltration, and (85%) of non-neoplastic complications were facilitated dark signal, with a significant P-value of 0.001. The ADC map demonstrated a significant decrease in ADC value in cases of neoplastic infiltration in bone marrow. The optimal cut-off ADC value for detecting neoplastic infiltration was found to be