Spleen volume assessment in Ph-negative chronic myeloproliferative neoplasms: a real-life study comparing ultrasonography vs. magnetic resonance imaging scans

Splenomegaly is a quite common clinical feature of Philadelphia (Ph) negative chronic myeloproliferative neoplasms (MPNs) and its presence may, in some cases, drives treatment decision. Most importantly, palpable splenomegaly is a minor criterion for both pre-fibrotic/early primary myelofibrosis and primary myelofibrosis (PMF) diagnosis, even if clinical assessment by physical examination is poorly reliable and accurate. On the other hand, despite the International Working Group-Myeloproliferative Neoplasms Research and Treatment and European LeukemiaNet guidelines defined spleen response criteria by palpation, they also recognized the highly subjective nature of spleen size assessment by physical examination, and recommended objective confirmation of volume reduction via computed tomography or magnetic resonance imaging (MRI). In particular, spleen volume (SV) reduction of at least 35% via MRI is typically the primary endpoint in PMF and in some polycythemia vera clinical trials. Nevertheless, this technique seems inconvenient in routine clinical practice. To simplify serial monitoring of spleen size by using ultrasonography (US), we retrospectively analyzed medical records of 39 newly diagnosed MPN patients who underwent spleen ultrasonography as well as MRI. The median SV assessed by US was 600 ml (range 200-5000 ml) while median SV evaluated by MRI was 553.1 ml (range 172-5140 ml), revealing a strong linear relationship between methods, with a correlation coefficient of r = 0.96 (95% CI 0.92-0.98, P < 0.0001). Our findings support the role of US into pre-screening assessments for clinical trials and practice, offering a pragmatic solution for evaluating SV in MPN patients and ultimately improving patient care and clinical decision-making in this complex disease landscape.