Diagnostic performance of diffusion weighted imaging of malignant and benign pulmonary nodules and masses: comparison with positron emission tomography.

Katsuo Usuda,Sumiko Maeda,Mitsuru Taniguchi,Hisao Tonami,Motoyasu Sagawa,Yasuaki Kuginuki,Yoshimichi Ueda,Masakatsu Ueno,Tsutomu Sakuma,Nozomu Motono,Yuichiro Machida,Munetaka Matoba,Makoto Tanaka

doi:10.7314/apjcp.2014.15.11.4629

Katsuo Usuda, Sumiko Maeda + Show 11 more

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https://doi.org/10.7314/apjcp.2014.15.11.4629

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Abstract

Diffusion-weighted imaging (DWI) makes it possible to detect malignant tumors based on the diffusion of water molecules. However, it is uncertain whether DWI has advantages over FDG-PET for distinguishing malignant from benign pulmonary nodules and masses. One hundred- forty-three lung cancers, 17 metastatic lung tumors, and 29 benign pulmonary nodules and masses were assessed in this study. DWI and FDG-PET were performed. The apparent diffusion coefficient (ADC) value (1.27 ± 0.35 ?10-3 mm2/sec) of malignant pulmonary nodules and masses was significantly lower than that (1.66 ± 0.58 ?10-3 mm2/sec) of benign pulmonary nodules and masses. The maximum standardized uptake value (SUV max: 7.47 ± 6.10) of malignant pulmonary nodules and masses were also significantly higher than that (3.89 ± 4.04) of benign nodules and masses. By using optimal cutoff values for ADC (1.44?10-3 mm2/sec) and for SUV max (3.43), which were determined with receiver operating characteristics curves (ROC curves), the sensitivity (80.0%) of DWI was significantly higher than that (70.0%) of FDG-PET. The specificity (65.5%) of DWI was equal to that (65.5%) of FDG-PET. The accuracy (77.8%) of DWI was not significantly higher than that (69.3%) of FDG- PET for pulmonary nodules and masses. As the percentage of bronchioloalveolar carcinoma (BAC) component in adenocarcinoma increased, the sensitivity of FDG-PET decreased. DWI could not help in the diagnosis of mucinous adenocarcinomas as malignant, and FDG-PET could help in the correct diagnosis of 5 out of 6 mucinous adenocarcinomas as malignant. DWI has higher potential than PET in assessing pulmonary nodules and masses. Both diagnostic approaches have their specific strengths and weaknesses which are determined by the underlying pathology of pulmonary nodules and masses.

Highlights

Positron emission tomography with 18-fluoro-2deoxy-glucose (FDG-PET) is widely accepted as an imaging modality of choice in tumor staging
Twentynine benign pulmonary nodules and masses consisted of 10 chronic pneumonias, 4 nontuberculous mycobacterias, 4 hamartomas, 3 pulmonary tuberculosises, 2 granulomas, 2 sarcoidosises, 2 lung abscesses, and 2 pulmonary scars
The details are as follows: pathological diagnoses were made in 16 benign pulmonary nodules and masses; bacterial diagnoses from cultured samples were made in 3 benign pulmonary nodules and masses, and roentgenographical diagnoses were made in the remaining 10 benign pulmonary nodules and masses

Summary

Introduction

Positron emission tomography with 18-fluoro-2deoxy-glucose (FDG-PET) is widely accepted as an imaging modality of choice in tumor staging. Diffusion of water molecules in malignant tumors is usually restricted compared to that in normal tissue, resulting in a decreased apparent diffusion coefficient (ADC) value (Szafer et al, 1995; Takahara et al, 2004). Diffusion-weighted imaging (DWI) makes it possible to detect malignant tumors based on the diffusion of water molecules. It is uncertain whether DWI has advantages over FDG-PET for distinguishing malignant from benign pulmonary nodules and masses. Conclusions: DWI has higher potential than PET in assessing pulmonary nodules and masses Both diagnostic approaches have their specific strengths and weaknesses which are determined by the underlying pathology of pulmonary nodules and masses

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