Ruben M. Vanheste MD, Presenter: Nothing to Disclose

Vincent Vandecaveye MD, Abstract Co-Author: Nothing to Disclose

Frederik De Keyzer MS, Abstract Co-Author: Nothing to Disclose

Gregor Verhoef PhD, Abstract Co-Author: Nothing to Disclose

Steven Dymarkowski MD, PhD, Abstract Co-Author: Nothing to Disclose

Diffusion weighted MRI (DWI) allows for tissue characterization based on changes in water mobility. The purpose of the study is to evaluate whole-body (WB-)DWI for differentiation and staging of lymphoma in comparison to (18)FDG-PET-CT.

Prior to treatment, 14 patients with histology proven lymphoma (2 Hodgkin, 12 Non-Hodgkin) underwent WB-DWI and PET-CT. WB-DWI was performed with a 3T MR system with b-values (s/mm²) of 0, 625 and 1250. The scan volume extended from head to pelvis (30 minute scan). On the native DWI images, all lymph nodes and lesion in bone, soft-tissues and organs were delineated, and ADC values were calculated based on all b-values. Signal Intensity (SI) at b1250 and ADC value were compared between FDG-positive and FDG-negative lesions. Subsequently, the patients were staged according to the Ann Arbor lymphoma staging system, using the WB-DWI findings and compared to PET-based staging of the disease. Statistical analysis was performed using unpaired two-tailed Student t tests.

The b1250 SI of FDG-positive sites in lymph nodes, bone and soft tissues was significantly higher compared to FDG-negative sites (P<0.001, P<0.001 and P=0.015, respectively), but no significant difference was observed in the spleen. ADC values of FDG-positive sites in lymph nodes, soft tissues and spleen was significantly lower than FDG-negative sites (P<0.001), however, no significant difference in bone was seen. ADC was most accurate for differentiation of nodal and splenic FDG-positive sites, whereas b1250 was most accurate for bony and soft tissue localizations. Sensitivity and specificity for detection of nodal disease was 96% and 90%, respectively and was 100% and 100% for extranodal involvement. There was a full concordance between staging based on WB-DWI compared to PET-CT (14/14)

WB-DWI showed high correlation to PET-CT for characterization and staging of lymphomas. ADC values were most accurate in nodal and splenic localizations, while bony and soft tissue localizations were easily detected using b1250 SI.

WB-DWI may offer an alternative for characterization and staging of lymphoma, avoiding the use of ionizing radiation and iodinated contrast.

Vanheste, R, Vandecaveye, V, De Keyzer, F, Verhoef, G, Dymarkowski, S, Use of Diffusion-weighted MRI for Characterization and Staging of Lymphoma in Comparison to (18)FDG-PET-CT: Preliminary Results.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5002655.html