Christian Buchbender, Presenter: Nothing to Disclose

Axel Scherer MD, Abstract Co-Author: Nothing to Disclose

Jan Terjung MSc, Abstract Co-Author: Nothing to Disclose

Jörg Handschel, Abstract Co-Author: Nothing to Disclose

Gerald Antoch MD, Abstract Co-Author: Speaker, Siemens AG Speaker, Bayer AG

Till Alexander Heusner MD, Abstract Co-Author: Nothing to Disclose

Magnetic resonance imaging (MRI) and 18F-FDG positron emission tomography (PET) are routinely applied for N-staging in head and neck cancer patients. Sequentially performed PET and MRI with post-hoc image fusion, as well as integrated PET/MRI have been shown to be as accurate as PET/CT for this task. Diffusion-weighted MRI (DWI) has been shown to be of use for the detection of neck lymph node metastases. We experienced that inverted DWI images mimic the visual impression of PET studies. Therefore the purpose of this study was to compare the diagnostic accuracy of PET/MRI and DWI/MRI fusion images for the detection of neck lymph node metastases in patients with head and neck malignancies.

Preoperative 3Tesla- MRI, including DWI and gadolinium enhanced sequences, and 18F-FDG PET/Computed tomography were sequentially performed in 14 consecutive patients (age 67±11 years [mean± SD]) with head and neck cancer. For each patient, using an investigational image fusion software, PET and inverted DWI were fused with the corresponding T1-weighted fat supressed gadolinium enhanced MR study, respectively. Neck levels (Ia, Ib, IIa, IIb, III, IV, Va, Vb) were bilateraly evaluated for presence of lymph node metastases on PET/MRI and DWI/MRI images, seperately. Bilateral neck dissection was performed in all patients. Histo-pathologic workup derived as the reference standard on a neck level basis. The diagnostic accuracy of PET/MRI and DWI/MRI was compared using the McNemar test.

PET/MRI detected 26/28, DWI/MRI 20/28 neck levels positive for lymph node metastases. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of PET/MRI was 72%, 96%, 69%, 97% and 93%. DWI/MRI with the respective values of 36%, 95%, 45%, 92% and 88% was significantly less accurate (p=0.04).

PET/MRI fusion yields a sufficient diagnostic accuracy for lymph node metastases detection. DWI/MRI fusion images are inaccurate for staging in head and neck cancer patients.

This work adds relevant information on the diagnostic accuracy of PET and MRI, including DWI, based on a reliable gold standard and enhances the understanding of the reliability of imaging techniques.

Buchbender, C, Scherer, A, Terjung, J, Handschel, J, Antoch, G, Heusner, T, Diagnostic Accuracy of PET/MRI and DWI/MRI Fusion Images for Neck Lymph Node Staging in Head and Neck Cancer.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12032345.html