Marcelo Araujo Queiroz MD, Presenter: Nothing to Disclose

Ken Herrmann, Abstract Co-Author: Nothing to Disclose

Martin W. Huellner MD, Abstract Co-Author: Nothing to Disclose

Andreas K. Buck MD, Abstract Co-Author: Nothing to Disclose

Paul Stolzmann MD, Abstract Co-Author: Nothing to Disclose

Gustav K. Von Schulthess MD, PhD, Abstract Co-Author: Research Grant, General Electric Company

Patrick Veit-Haibach MD, Abstract Co-Author: Research Grant, Bayer AG Resaarch Grant, F. Hoffmann-La Roche Ltd Research Grant, General Electric Company

To prospectively evaluate the accuracy of DWI compared to FDG-PET/MRI and FDG-PET/CT using a tri-modality PET/CT-MRI system allowing for a one stop examination in a realistic everyday clinical setting including pretreatment staging, interim- and end of treatment restaging, as well as surveillance of lymphoma patients.

From 04/12 to 01/14 a total of 83 FDG-PET/CT scans including an additional scientific MRI including a whole body DWI on a tri-modality setup were performed in 62 patients. PET/CT, PET/MRI and DWI were independently analyzed. DWI findings considered malignant were scored based of their ADC mean value and categorized on a 4 point scale. Independent analyses were performed using different ADC scores as cut-off (≤1, ≤2, and ≤3) for rating lesions as positive for lymphoma. Imaging findings were validated by biopsy (n=21), by follow-up imaging comprising CT, FDG-PET/CT and/or FDG-PET/MRI (n=32) or clinically (n=25). Due to loss to follow-up five scans (all negative on FDG-PET/CT) could not be validated.

FDG-PET/CT and FDG-PET/MRI detected disease presence in 29 cases and was true negative in the 54 cases. Both, PET/CT and PET/MRI correctly identified the clinically defined stage as well as all known 191 lesions. Use of different cut-offs for interpretation of DWI resulted in sensitivities and specificities for disease detection ranging from 34.5% to 82.8% and 63.0% to 92.6%, respectively. Regarding determination of the correct stage, corresponding sensitivities ranged between 17.2% and 20.7%, and the specificities calculated to 63.0% and 92.6%. On a lesion basis, corresponding sensitivities and specificities ranged between 3.4% and 6.9%, and 63.0% and 92.6%, respectively.

In lymphoma patients, FDG-PET/CT and FDG-PET/MRI outperformed DWI regarding sensitivity and specificity in a realistic everyday clinical setting. FDG-PET/MRI findings were in agreement with FDG-PET/CT for stage definition and disease detection.

FDG-PET/MRI appears feasible for diagnostic work-up of lymphoma patients, whereas routine use of DWI is less promising due to a limited accuracy compared to FDG-PET/CT.

Queiroz, M, Herrmann, K, Huellner, M, Buck, A, Stolzmann, P, Von Schulthess, G, Veit-Haibach, P, Clinical Impact of DWI and FDG-PET/MRI in Comparison to FDG-PET/CT in Lymphoma Patients.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019784.html