Shuo Li MD, Presenter: Nothing to Disclose

Huadan Xue MD, Abstract Co-Author: Nothing to Disclose

Fei Sun MS, Abstract Co-Author: Employee, General Electric Company, China

Zheng Yu Jin MD, Abstract Co-Author: Nothing to Disclose

To evaluate the diagnostic accuracy of WB-DWI for staging of lymphoma patients in comparison to PET.

8 patients with histologically proven Non-Hodgkin lymphoma (n= 6) or Hodgkin lymphoma (n=2) underwent tumor staging by WB-DWI and PET within two weeks. WB-DWI was performed by using short TI inversion recovery diffusion weighted echo planar imaging (STIR-DWEPI) sequence with free breathing and build in body coil. Total scan time was 30 minutes for 5 stations covering from head to thigh with b values of 0 and 800 s/mm2. Each station composed of 39 slices with 7mm thickness and 1mm overlap. Conventional FSE T2-weighted image was also performed at same location. High resolution 3D-MIP images of WB-DWI were obtained and displayed by using black and white inverse gray scales, in order to compare with PET easier. Low intensity in inverted DWI image with ADC value lower than 1.2 mm2/s was used as malignance marker. T2WI, histology and a clinical follow-up served as the standards of reference.

In 8 cases WB-DWI identified 71 pathologic nodal lesions, while PET demonstrated 62 lesions. Concordance between WB-DWI and PET occurred in 6 of 8 patients (75%). All pathologic lymph nodes with a diameter greater than 5 mm detected by PET could be visualized by WB-DWI. In one case of non-Hodgkin lymphoma, one subcarinal lymph node was initially overlooked by PET as a result of low spatial resolution and insufficient contrast with spine. It was clearly visible on WB-DWI and was demonstrated on T2WI. Besides WB-DWI showed more lymph nodes (n=4) than PET at the right sided neck, which were proven by histology. In another patient, WB-DWI detected more pathologic nodes (n=7) in the left iliac area, which were not identified by PET and confirmed by follow-up.

WB-DWI will be a valuable imaging modality for staging of patients with malignant lymphoma. Compared with PET, WB-DWI was more sensitive in the detection of pathologic lymph nodes in the neck and the iliac area.

Accurate staging for patients with malignant lymphoma are of vital importance for therapeutic management and follow-up. High false-positive ratio and cost have limited the utility of PET in oncology.

Li, S, Xue, H, Sun, F, Jin, Z, Whole Body Diffusion-weighted MR Imaging (WB-DWI) Compared with PET for Malignant Lymphoma Staging.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5016158.html