Scatter plots including the corresponding regression grade for all lymph node metastases (A, n = 91), lymph node metastases of adenocarcinoma (B, n = 54) and lymph node metastases of SCC (C, n = 29) between SUV_max and ADC_mean.

<p>Scatter plots including the corresponding regression grade for all lymph node metastases (A, n = 91), lymph node metastases of adenocarcinoma (B, n = 54) and lymph node metastases of SCC (C, n = 29) between SUV_max and ADC_mean.</p

Correlation of the Apparent Diffusion Coefficient (ADC) with the Standardized Uptake Value (SUV) in Lymph Node Metastases of Non-Small Cell Lung Cancer (NSCLC) Patients Using Hybrid 18F-FDG PET/MRI

<div><p>Objective</p><p>To compare the apparent diffusion coefficient (ADC) in lymph node metastases of non-small cell lung cancer (NSCLC) patients with standardized uptake values (SUV) derived from combined 18F-fluoro-deoxy-glucose-positron emission tomography/magnetic resonance imaging (18F-FDG PET/MRI).</p><p>Material and Methods</p><p>38 patients with histopathologically proven NSCLC (mean age 60.1 ± 9.5y) received whole-body PET/CT (Siemens mCT™) 60min after injection of a mean dose of 280 ± 50 MBq 18F-FDG and subsequent PET/MRI (mean time after tracer injection: 139 ± 26 min, Siemens Biograph mMR). During PET acquisition, simultaneous diffusion-weighted imaging (DWI, b values: 0, 500, 1000 s/mm²) was performed. A maximum of 10 lymph nodes per patient suspicious for malignancy were analyzed. Regions of interest (ROI) were drawn covering the entire lymph node on the attenuation-corrected PET-image and the monoexponential ADC-map. According to histopathology or radiological follow-up, lymph nodes were classified as benign or malignant. Pearson’s correlation coefficients were calculated for all lymph node metastases correlating SUV_max and SUV_mean with ADC_mean.</p><p>Results</p><p>A total of 146 suspicious lymph nodes were found in 25 patients. One hundred lymph nodes were eligible for final analysis. Ninety-one lymph nodes were classified as malignant and 9 as benign according to the reference standard. In malignant lesions, mean SUV_max was 9.1 ± 3.8 and mean SUV_mean was 6.0 ± 2.5 while mean ADC_mean was 877.0 ± 128.6 x10^-5 mm²/s in PET/MRI. For all malignant lymph nodes, a weak, inverse correlation between SUV_max and ADC_mean as well as SUV_mean and ADC_mean (r = -0.30, p<0.05 and r = -0.36, p<0.05) existed.</p><p>Conclusion</p><p>The present data show a weak inverse correlation between increased glucose-metabolism and cellularity in lymph node metastases of NSCLC patients. 18F-FDG-PET and DWI thus may offer complementary information for the evaluation of treatment response in lymph node metastases of NSCLC.</p></div

Liver metastases not visible in PET/CT: detection rate in different MR-sequences.

<p>Liver metastases not visible in PET/CT: detection rate in different MR-sequences.</p

Flow-chart depicting the process of inclusion for all analyzed lymph nodes.

<p>Flow-chart depicting the process of inclusion for all analyzed lymph nodes.</p

MR imaging sequence parameters.

<p>MR imaging sequence parameters.</p

Tumor characteristics in all 25 included patients with lymph nodes suspicious for malignancy in PET/CT and PET/MRI.

<p>Tumor characteristics in all 25 included patients with lymph nodes suspicious for malignancy in PET/CT and PET/MRI.</p

Patient without liver metastases.

<p>PET/CT with a false positive result showing a hypodense pseudolesion with a diameter 9 mm in the CT dataset without correlate in PET. In the later acquired PET/MRI (C-E) no correlate in PET nor in the morphological datasets (D: T1w VIBE portal-venous phase; E: T2w TSE fs).</p

Sequence parameters for the diagnostic MR-sequences used in PET/MRI for NSCLC patients.

<p>Sequence parameters for the diagnostic MR-sequences used in PET/MRI for NSCLC patients.</p

Accuracy of [¹⁸F]FDG PET/MRI for the Detection of Liver Metastases

<div><p>Background</p><p>The aim of this study was to compare the diagnostic accuracy of [¹⁸F]FDG-PET/MRI with PET/CT for the detection of liver metastases.</p><p>Methods</p><p>32 patients with solid malignancies underwent [¹⁸F]FDG-PET/CT and subsequent PET/MRI of the liver. Two readers assessed both datasets regarding lesion characterization (benign, indeterminate, malignant), conspicuity and diagnostic confidence. An imaging follow-up (mean interval: 185±92 days) and/-or histopathological specimen served as standards of reference. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for both modalities. Accuracy was determined by calculating the area under the receiver operating characteristic (ROC) curve. Values of conspicuity and diagnostic confidence were compared using Wilcoxon-signed-rank test.</p><p>Results</p><p>The standard of reference revealed 113 liver lesions in 26 patients (malignant: n = 45; benign: n = 68). For PET/MRI a higher accuracy (PET/CT: 82.4%; PET/MRI: 96.1%; p<0.001) as well as sensitivity (67.8% vs. 92.2%, p<0.01) and NPV (82.0% vs. 95.1%, p<0.05) were observed. PET/MRI offered higher lesion conspicuity (PET/CT: 2.0±1.1 [median: 2; range 0–3]; PET/MRI: 2.8±0.5 [median: 3; range 0–3]; p<0.001) and diagnostic confidence (PET/CT: 2.0±0.8 [median: 2; range: 1–3]; PET/MRI 2.6±0.6 [median: 3; range: 1–3]; p<0.001). Furthermore, PET/MRI enabled the detection of additional PET-negative metastases (reader 1: 10; reader 2: 12).</p><p>Conclusions</p><p>PET/MRI offers higher diagnostic accuracy compared to PET/CT for the detection of liver metastases.</p></div

Pearson’s correlation coefficient between SUV_max / ADC_mean and SUV_mean / ADC_mean in different subgroups of malignant lymph nodes (n = 91).

<p>* not performed due to small N</p><p>Pearson’s correlation coefficient between SUV_max / ADC_mean and SUV_mean / ADC_mean in different subgroups of malignant lymph nodes (n = 91).</p