Main advantages of MRI:
  - Much more sensitive than plain radiography in
detecting bone disease.
    Bone marrow infiltration in MRI may be detected in about 40% of patients with negative X-rays.
    Ideally, all patients with normal skeletal surveys should have an MRI.
  - It allows direct visualization of bone marrow with high spatial resolution.
    T2-weighted images show signal enhancement in areas of BM replacement with tumor cells.
  - It allows visualization of soft tissue masses extending from the bone lesions
  - Technique of choice to detect spinal cord compression or nerve compression
  - Technique of choice to detect avascular necrosis of bones due to corticosteroids
  - It can distinguish benign versus malignant vertebral compression fractures

MRI of the spine and pelvis should be obtained in all patients with solitary plasmacytoma or smoldering myeloma, because the detection of focal lesions can change the diagnosis to symptomatic multiple myeloma.


Five different infiltration patterns can be differentiated:
 1 - Normal appearance of bone marrow (30%)
 2 - Focal involvement (30%)
 3 - Diffuse homogeneous infiltration (25%)
 4 - Combined diffuse and focal infiltration (10%)
 5 - "Salt-and-pepper" pattern with heterogeneous bone marrow (5%)
      (mixture of small hypointense and hyperintense spots)

Typically, the vertebral bodies are hyperintense (i.e., brighter than the intervertebral disks) on T1-weighted images, and hypointense (i.e, darker than the intervertebral disks) on fat-suppressed T2-weighted images. If in the bone marrow the cellular component increases and the fatty component decreases, the signal decreases on T1 and it increases on T2 and STIR (= short time inversion recovery) images.
Myeloma lesions are hypointense on T1, hyperintense on T2, and hyperintense on STIR with enhancement on post-contrast T1 sequence. Instead, vertebral body hemangiomas are hyperintense on T1 and T2 sequences due to fat content, and the high signal disappears on the STIR sequence.
Patients without bone marrow infiltration in MRI at the time of diagnosis have a significantly longer survival than patients with bone marrow infiltration.



Focal lesions in vertebral bodies seen at MRI of the spine (my personal archive):






MRI of the cervical spine showing a severe compression of C3 (my personal archive):





MRI of the spine showing severe thoracic kyphosis due to compression fractures (my personal archive):





The following MRI of the spine summarizes the complications of myeloma involvement of the spine, with multiple compression fractures of several vertebral bodies, severe kyphotic deformity, and spinal cord compression (my personal archive):




Lytic lesion in the vertebral body of T8 at MRI of the spine (my personal archive):




Plasmacytoma of the skull producing a significant mass effect in the underlying brain parenchyma (my personal archive):




Magnetic resonance imaging as a supplement for the clinical staging system of Durie and Salmon?
Cancer. 2002 Sep 15;95(6):1334-45.
Baur A, Stäbler A, Nagel D, Lamerz R, Bartl R, Hiller E, Wendtner C, Bachner F, Reiser M.
This study evaluated 77 MM patients with MRI of the thoracic and lumbar spine using a three-grade scale:
 - Stage I: no focal or diffuse infiltration
 - Stage II: 1-10 foci or mild diffuse infiltration
 - Stage III: more than 10 foci or strong diffuse infiltration
Of 77 patients, 25 would have been understaged using the Durie-Salmon staging system without the MRI findings, and 8 patients would have been understaged if the staging was based only on MRI. The authors proposed to combine the MRI findings in the Durie-Salmon staging system. The infiltration patterns had no significant effect on survival, but the combination of MRI and Durie-Salmon staging system was highly significant with respect to survival. The MRI staging I-III was independent of the staging system of Durie and Salmon.

Whole-body MR imaging of bone marrow.
Eur J Radiol. 2005 Jul;55(1):33-40.
Schmidt GP, Schoenberg SO, Reiser MF, Baur-Melnyk A.

Role of MRI for the diagnosis and prognosis of multiple myeloma.
Eur J Radiol. 2005 Jul;55(1):56-63.
Baur-Melnyk A, Buhmann S, Dürr HR, Reiser M.

Prognostic significance of magnetic resonance imaging of bone marrow in previously untreated patients with multiple myeloma.
Ann Oncol. 2005 Nov;16(11):1824-8.
Moulopoulos LA, Gika D, Anagnostopoulos A, Delasalle K, Weber D, Alexanian R, Dimopoulos MA.

Prognostic significance of focal lesions in whole-body magnetic resonance imaging in patients with asymptomatic multiple myeloma.
J Clin Oncol. 2010 Mar 20;28(9):1606-10.
Hillengass J, Fechtner K, Weber MA, Bäuerle T, Ayyaz S, Heiss C, Hielscher T, Moehler TM, Egerer G, Neben K, Ho AD, Kauczor HU, Delorme S, Goldschmidt H.
149 patients with asymptomatic multiple myeloma underwent whole-body skeletal MRI. Focal lesions were detected in 28% of cases. The presence of focal lesions and a number >1 of focal lesions were strong prognostic factors for progression into symptomatic myeloma.

Role of magnetic resonance imaging in the management of patients with multiple myeloma: a consensus statement.
J Clin Oncol. 2015 Feb 20;33(6):657-64.
Dimopoulos MA, Hillengass J, Usmani S, Zamagni E, Lentzsch S, Davies FE, Raje N, Sezer O, Zweegman S, Shah J, Badros A, Shimizu K, Moreau P, Chim CS, Lahuerta JJ, Hou J, Jurczyszyn A, Goldschmidt H, Sonneveld P, Palumbo A, Ludwig H, Cavo M, Barlogie B, Anderson K, Roodman GD, Rajkumar SV, Durie BG, Terpos E.

Prospective Evaluation of Magnetic Resonance Imaging and 18-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography at Diagnosis and Before Maintenance Therapy in Symptomatic Patients With Multiple Myeloma Included in the IFM/DFCI 2009 Trial: Results of the IMAJEM Study.
J Clin Oncol. 2017 Sep 1;35(25):2911-2918.
Moreau P, Attal M, Caillot D, Macro M, Karlin L, Garderet L, Facon T, Benboubker L, Escoffre-Barbe M, Stoppa AM, Laribi K, Hulin C, Perrot A, Marit G, Eveillard JR, Caillon F, Bodet-Milin C, Pegourie B, Dorvaux V, Chaleteix C, Anderson K, Richardson P, Munshi NC, Avet-Loiseau H, Gaultier A, Nguyen JM, Dupas B, Frampas E, Kraeber-Bodere F.
In this prospective study comparing skeletal MRI and PET/CT in 134 patients with myeloma, no difference was found in the detection of bone lesions at diagnosis between the 2 techniques.




WB DW-MRI is superior to conventional MRI in terms of:
  - Speed (about 45 minutes)
  - Coverage: about half lesions would be missed by imaging the spine alone
  - Sensitivity: it provides a better contrast between normal and myelomatous marrow, compared to STIR and contrast -enhanced MRI.

WB DW-MRI is very helpful in ruling out the presence of bone lesions in patients with presumed smoldering myeloma or solitary bone plasmacytoma.



Giampaolo Talamo, M.D.