Diffusion imaging of the vertebral bone marrow

Whole-body MRI, dynamic contrast-enhanced MRI, and diffusion-weighted imaging for the staging of multiple myeloma

Magnetic resonance imaging (MRI) is the most sensitive imaging technique for the detection of bone marrow infiltration, and has therefore recently been included in the new diagnostic myeloma criteria, as proposed by the International Myeloma Working Group. Nevertheless, conventional MRI only provides anatomical information and is therefore only of limited use in the response assessment of patients with multiple myeloma. The additional information from functional MRI techniques, such as diffusion-weighted imaging and dynamic contrast-enhanced MRI, can improve the detection rate of bone marrow infiltration and the assessment of response. This can further enhance the sensitivity and specificity of MRI in the staging of multiple myeloma patients. This article provides an overview of the technical aspects of conventional and functional MRI techniques with practical recommendations. It reviews the diagnostic performance, prognostic value, and role in therapy assessment in multiple myeloma and its precursor stages.

Evaluation of Diffusion-weighted MR Imaging as a Technique for Detecting Bone Marrow Edema in Patients with Osteitis Pubis

Purpose:

Our aims were to determine the feasibility of diffusion-weighted magnetic resonance imaging (DWI) in the detection of bone marrow edema (BME) and explore the apparent diffusion coefficient (ADC) alterations in patients with osteitis pubis (OP).

Materials and Methods:

42 consecutive patients clinically suspected to have athletic pubalgia and 31 control subjects were enrolled in the study. All subjects underwent diagnostic focused magnetic resonance imaging (MRI) and DWI at b values of 0 and 600 s/mm². Two radiologists reviewed the images for the presence of active OP. The presence of subchondral BME and contrast enhancement were considered to indicate active OP. ADC values were measured from public bodies of both groups. DWI results were correlated with routine MRI findings. Receiver-operating-characteristic curves were formed. Cut-off values for ADC, sensitivity and specificity values were measured.

Results:

36/42 (85%) of the cases had BME/enhancement on routine MRIs and identified as active OP. ADC measurements of the patients were greater than the controls (P < 0.05). For the optimal cut-off values DWI showed sensitivity and specificity values of 97.3%, and 90.3%, for the right, and 97.1%, and 96.7% for the left side, respectively (Area under the curve 0.965 and 0.973). Intra-and inter-rater reliability for readers were substantial-perfect for all sessions.

Conclusion:

DWI is fast, accurate, and highly reproducible technique for the detection of BME in patients with active OP. It allows distinct bone marrow contrast without the use of gadolinium contrast, increases visual perception of active lesions, gives objective information by quantifying the diffusion coefficients, thus increase diagnostic confidence. We suggest the use of DWI as a cost-effective adjunctive tool for the diagnosis of active OP particularly in early cases and inconclusive diagnostic MRI. Future studies are necessary to determine the utility of DWI to evaluate severity of the disease and treatment response before returning athletes to play.

Diffusion-weighted imaging outside the brain: Consensus statement from an ISMRM-sponsored workshop

The significant advances in magnetic resonance imaging (MRI) hardware and software, sequence design, and postprocessing methods have made diffusion-weighted imaging (DWI) an important part of body MRI protocols and have fueled extensive research on quantitative diffusion outside the brain, particularly in the oncologic setting. In this review, we summarize the most up-to-date information on DWI acquisition and clinical applications outside the brain, as discussed in an ISMRM-sponsored symposium held in April 2015. We first introduce recent advances in acquisition, processing, and quality control; then review scientific evidence in major organ systems; and finally describe future directions. J. Magn. Reson. Imaging 2016;44:521-540.

Diffusion-weighted MRI for detection of hepatic osteodystrophy in primary sclerosing cholangitis: a comparison study with dual-energy X-ray absorptiometry

PURPOSE

Osteodystrophy is a frequent complication in primary sclerosing cholangitis (PSC). The aim was to test the feasibility of vertebral bone diffusion-weighted imaging (DWI) in routine liver MRI for detection of osteoporosis using dual-energy X-ray absorptiometry (DXA) as gold standard.

MATERIALS AND METHODS

Forty PSC patients (50 ± 12.6 years) and ten controls (49.5 ± 13.0 years) were scanned using a DWI spin echo echo-planar sequence (b-factors 0-800 s/mm²) on a 3-T MRI system and DXA (76 kVp). The apparent diffusion coefficient (ADC) and T-score were correlated to laboratory and clinical details using Pearson correlation.

RESULTS

In DXA-diagnosed osteoporosis (n = 3) and osteopenia (n = 12), the mean ADC was decreased (0.26 ± 0.03 and 0.30 ± 0.07 × 10^-3 mm²/s) compared to patients with normal DXA scan results (n = 25; 0.32 ± 0.06 × 10^-3 mm²/s). No significant correlation of the ADC and T-score (r = 0.24; p = 0.13) was found, but the T-score correlated significantly to disease duration (r = -0.33; p = 0.04). In patients with prednisolone therapy (n = 7), the DXA T-score was significantly lower (-1.46 ± 0.49 vs. -0.16 ± 0.23; p = 0.03).

CONCLUSION

Diffusion-weighted MRI of the vertebral spine is a feasible technic to detect diffusion alterations caused by osteoporosis but lacks diagnostic capacities for diagnosing minor reductions of the bone mineral density detected by DXA.