Comparison of Assesment of Imaging Response with Magnetic Resonance (MR) and ¹⁸fdg-PET/TC in Multiple Myeloma (MM). Single Centre Experience

Introduction: Conventional radiography remains the “gold standard” technique for bone involvement assessment in patients with multiple myeloma (MM). Newer imaging modalities such as whole-body Magnetic Resonance (MR) and ¹⁸FDG-PET/CT have emerged as more sensitive techniques than routine skeletal survey in the detection of bone involvement in the diagnostic and follow up of patients with MM. The advantages and disadvantages of MR and ¹⁸FDG-PET/CT are discussed.

Patients and methods: We have retrospectively analyzed 12 patients since 2012 to 2014 with multiple myeloma in our institution whose bone involvement was evaluated with MR and ¹⁸FDG-PET/CT. Age range: 36-70. Seven patients were female and five were male. Eight cases were treated with an induction regimen containing bortezomib, three cases with chemotherapy with alternating VBCMP/VBAD and one of them with VAD. After induction, ten of them received autologous stem cell transplantation (ASCT), one patient allogeneic stem cell transplantation and one patient no transplantation.

Results: All patients presented bone lesions on MR and all of them were also positive at PET/CT. One showed leptomeningeal involvement on RM and PET. Regarding extramedullar disease two patients presented soft tissue masses and in other two cases there was ganglionar involvement, all of them positives by both techniques.

Of nine evaluable patients after complete treatment, six of them have a negative PET and three have a low positive SUV value, however eight of them still had persistent residual lesions on MR, what could indicate not stringent complete response. The patient with leptomeningeal involvement had both MR and PET negative result after treatment.

Comments and conclusions: Our data suggest that whole-body MR and ¹⁸FDG-PET/CT provide valuable complementary information, MR could be superior to assess extent of lesions and PET to monitor disease activity and to detect asymptomatic relapse. The optimal imaging technique for the management of patients with MM is not well defined and our proposal is a multimodality imaging approach according to individualized criteria.

References:

• Caers J et al. The role of positron emission tomography-computed and magnetic resonance imaging in diagnosis and follow-up of multiple myeloma. Haematologica 2014;99(4):629-637. doi:10.3324/haematol.2013.091918.

• Agarwal A et al. Evolving Role of FDG PET/CT in Multiple Myeloma Imaging and Management. AJR 2013;200:884-890.

• Dimopoulos D et al. International myeloma working group consensus statement and guidelines regarding the current role of imaging techniques in the diagnosis and monitoring of multiple Myeloma. Leukemia 2009, 1–12. doi:10.1038/leu.2009.89