Evaluating and monitoring bone marrow hypoplasia in adults with aplastic anemia via high-resolution iliac magnetic resonance imaging in the current era

Abstract

The diagnosis and monitoring of aplastic anemia (AA) rely heavily on a complete blood count (CBC), and multiple-site bone marrow (BM) aspirations and biopsies. However, these approaches have certain limitations. We aimed to assess high-resolution magnetic resonance imaging (MRI) as a complementary approach for evaluating BM hypoplasia and monitoring treatment response in adults with AA in the current era. Twelve newly diagnosed AA patients and 12 sex- and age-matched healthy controls were enrolled in this study from January 2017 to August 2018. A bilateral iliac 3.0T MRI was used to collect data for each subject, and the signal intensity on the T1-weighted images (T1WIs) were expressed as a contrast-to-noise ratio (CNR). The MRI, CBC, and BM biopsy data were analyzed and compared. A qualitative analysis identified a significant difference in MRI signal characteristics between the AA group and the healthy control group. The clinical classifications of very severe aplastic anemia (VSAA) and severe aplastic anemia (SAA) corresponded to pattern I and pattern II on the MR images, respectively. However, this imaging classification did not correlate with the biopsy-based BM cellularity measure. A quantitative analysis showed a significantly higher signal intensity in AA patients than in controls. A within-group comparison revealed that more severe types of AA, based on the clinical classification, corresponded to stronger signals. Notably, MRI could detect treatment response earlier than CBC, regardless of whether there were improvements in hematopoiesis. MRI can be used to predict the therapeutic effects in patients with AA and is an important complementary tool for evaluating and monitoring BM hypoplasia.

Advantages of Digital Technology in the Assessment of Bone Marrow Involvement by Magnetic Resonance Images

“…When there is a response to treatment, a heterogeneous pattern is observed in the vertebral bodies formed by hypointense foci in T1 and T2 that represent foci of hematopoiesis. MRI is a good method for assessing response to treatment [34,35], taking into account that sometimes, these foci appear in vertebrae and are not seen in the pelvis, where the biopsy is normally performed if the patient recovers completely from his aplasia, the marrow returns to the normal appearance and distribution for his age.…”

“…In case of irradiation at low doses, marrow regeneration in MRI could be confused with cellular infiltration of another type. Irradiation doses higher than 50 Gy are associated with complete replacement by fatty marrow due to irreversible marrow extinction [34].…”

Normal Bone Marrow and Non-neoplastic Systemic Hematopoietic Disorders in the Adult

“…52 Fatty replacement of marrow results in a generalized increased marrow SI on T1W TSE sequences and corresponding low SI on STIR. 53 MRI can be used to guide marrow biopsy and monitor response to treatment. Treatment with repeated blood transfusions produces either diffuse or focal areas of red marrow recovery within the otherwise diffusely fatty marrow.…”