The effectiveness of 18F-FDG PET/CT combined with STIR MRI for diagnosing nodal involvement in the thorax.
The purpose of this study was to compare the efficacy of short-tau inversion-recovery (STIR) MRI and 18F-FDG PET/CT for the detection of metastasis in mediastinal and hilar lymph nodes in patients with lung cancer.


METHODS
Ninety-three patients with known or suspected lung cancer with mediastinal and hilar lymph node swelling underwent STIR MRI and 18F-FDG PET/CT examinations. STIR MRI scans were obtained with a 2% copper sulfate phantom placed along the back of each patient, with the lymph node-to-phantom ratio calculated for quantitative analysis. For qualitative analysis, the results of all STIR MRI scans were evaluated using a 5-point visual scoring system. To evaluate the diagnostic capabilities of STIR MRI and 18F-FDG PET/CT, we used receiver-operating-characteristic curve analysis to determine the optimal thresholds for the lymph node-to-phantom ratio, visual score, and maximal standardized uptake value. Further, the capability of each to determine N-stage was compared in each patient using the McNemar test.


RESULTS
A total of 137 lymph nodes (82 malignant lesions, 55 benign lesions) were analyzed. When optimal threshold values were adopted, the quantitative and qualitative sensitivity, specificity, and accuracy of STIR MRI were not significantly different from those of 18F-FDG PET/CT. However, 18F-FDG PET/CT in combination with qualitative STIR MRI analysis had a significantly higher capability to detect nodal involvement on an individual-patient basis (96.9% specificity, 90.3% accuracy) than did 18F-FDG PET/CT alone (65.6% specificity, 81.7% accuracy).


CONCLUSIONS
We found that the diagnostic capability of STIR MRI was not significantly different from that of 18F-FDG PET/CT. However, when those methods were combined, the diagnostic capability for N-staging was significantly improved.
Morikawa
Miwa
M
Department of Respiratory Medicine, University of Fukui, Fukui, Japan.
Demura
Yoshiki
Y
Ishizaki
Takeshi
T
Ameshima
Shingo
S
Miyamori
Isamu
I
Sasaki
Masato
M
Tsuchida
Tatsuro
T
Kimura
Hirohiko
H
Fujibayashi
Yasuhisa
Y
Okazawa
Hidehiko
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary; D008875:Middle Aged; D009367:Neoplasm Staging; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D013902:Radiography, Thoracic; D012680:Sensitivity and Specificity; D013909:Thorax / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18