DWI was superior to both FDG-PET/CT and contrast-enhanced CT for mucosa-associated lymphoid tissue (MALT) lymphoma, Dr. Thomas Knogler and colleagues found. Contrast-enhanced CT is the current modality of choice for this form of lymphoma.
The prospective study included one group of patients with FDG-avid lymphoma (such as Hodgkin's and follicular lymphoma) and a second group of patients with lymphoma of variable FDG-avidity (MALT lymphoma and small lymphocytic lymphoma). All patients underwent DWI-MRI and FDG-PET/CT with a venous-phase, contrast-enhanced CT series.
DWI-MRI achieved sensitivity of 97% in the first group of 100 patients. In the second group of 40 patients, DWI, FDG-PET/CT, and contrast-enhanced CT reached sensitivities of 94%, 61%, and 71%, respectively.
In patients with FDG-avid lymphoma, DWI was only slightly inferior to FDG-PET/CT in terms of pretherapeutic regional assessment and staging, the researchers concluded. In patients with lymphoma subtypes that show variable FDG-avidity, particularly MALT lymphoma, DWI was superior to both FDG-PET/CT and contrast-enhanced CT.
"DWI-MRI may be a general alternative to F-18 FDG PET/CT for pretherapeutic lymphoma staging," Knogler and colleagues wrote.
The findings are "particularly relevant for younger lymphoma patients because, contrary to F-18 FDG PET/CT or contrast-enhanced CT, DWI-MRI is not associated with potentially harmful radiation and may thus be better suited for lifelong follow-up," they added.