Christina Pfannenberg MD, Presenter: Nothing to Disclose

Philip Aschoff MD, Abstract Co-Author: Nothing to Disclose

Matthias Philipp Lichy MD, Abstract Co-Author: Nothing to Disclose

Heinz-Peter Wilhelm Schlemmer MD, Abstract Co-Author: Nothing to Disclose

Matthias Reimold MD, Abstract Co-Author: Nothing to Disclose

Claus Detlef Claussen MD, Abstract Co-Author: Nothing to Disclose

To compare the diagnostic value of multiphase MSCT, MRI and [68Ga]-DOTATOC-PET in the detection of liver metastases in patients with neuroendocrine tumors (NET)

38 consecutive patients with proven NET underwent a [68Ga]-DOTATOC-PET/CT and liver MRI within a 1-30 day interval. PET/CT consisted of a non-enhanced attenuation scan and a bolus-triggered arterial and portal-venous contrast-enhanced CT followed by a whole-body PET with the somatostatin receptor ligand [68Ga]-DOTATOC. The 1.5T liver MRI comprised axial T2w TSE fs and T1w multi-phase contrast-enhanced 3D GRE sequences. Three readers analyzed images of each modality, blindly and independently for lesion number, size, location and enhancement pattern. The reference standard was given by PET in receptor positive patients, with allocating lesions below the PET resolution 10mm found in the same patient. Receptor negative patients were validated by follow-up and/or histology.

In 27/38 patients a total of 240 hepatic metastases were detected. The number of metastases detected on MRI, CT and PET was 239, 200 and 166 in 27, 27 and 22 patients, respectively. In 44% of patients MRI detected more liver metastases than PET and in 33% of patients more lesions than CT. 67% of metastases were best seen on arterial-phase CT and 59% were mainly detected on T2w MRI. In one patient with two known metastases PET revealed an additional lesion, which was not detected by MRI or CT. PET failed to detect liver metastases in 5 patients (18.5%) in whom MRI or CT was positive for metastases. In receptor positive patients the lesion detectability in PET was influenced by the lesion size with a limit of 8-10 mm.

MRI depicted the largest number of hepatic metastases and appears to be the method of choice for staging and liver evaluation before intervention in patients with NET. [68Ga]-DOTATOC-PET has a high specifity but impaired sensitivity by tumor receptor status and impact of lesion size on detection capacity.

In patients with neuroendocrine tumors MRI is recommended as first-line staging modality for the detection of hepatic metastases.

Pfannenberg, C, Aschoff, P, Lichy, M, Schlemmer, H, Reimold, M, Claussen, C, Detection of Liver Metastases from Neuroendocrine Tumors by [68Ga]-DOTATOC-PET/CT: Is There Still a Need for an Additional Liver MRI?.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011998.html