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

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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. 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.

Advantages of diffusion-weighted imaging over positron emission tomography-computed tomography in assessment of hilar and mediastinal lymph node in lung cancer.

BACKGROUND: The significance of diffusion-weighted imaging (DWI) is uncertain for the diagnosis of nodal involvement. The purpose of this study was to examine diagnostic capability of DWI compared with PET-CT for nodal involvement of lung cancer. METHODS: A total of 160 lung cancers (114 adenocarcinomas, 36 squamous cell carcinomas, and 10 other cell types) were analyzed in this study. DWI and PET-CT were performed preoperatively. RESULTS: The optimal cutoff values to diagnose metastatic lymph nodes were 1.70 × 10(-3) mm(2)/s for ADC value and 4.45 for SUVmax. DWI correctly diagnosed N staging in 144 carcinomas (90 %) but incorrectly diagnosed N staging in 16 (10 %) [3 (1.9 %) had overstaging, 13 (8.1 %) had understaging]. PET-CT correctly diagnosed N staging in 133 carcinomas (83.1 %) but incorrectly diagnosed N staging in 27 (16.8 %) [4 (2.5 %) had overstaging, 23 (14.4 %) had understaging]. Sensitivity, accuracy, and negative predictive value for N staging by DWI were significantly higher than those by PET-CT. Of the 705 lymph node stations examined, 61 had metastases, and 644 did not. The maximum diameter of metastatic lesions in lymph nodes were 3.0 ± 0.9 mm in 21 lymph node stations not detected by either DWI or PET-CT: 7.2 ± 4.1 mm in 39 detected by DWI, and 11.9 ± 4.1 mm in 24 detected by PET-CT. There were significant differences among them. The sensitivity (63.9 %) for metastatic lymph node stations by DWI was significantly higher than that (39.3 %) by PET-CT. The accuracy (96.2 %) for all lymph node stations by DWI was significantly higher than that (94.3 %) by PET-CT. CONCLUSIONS: DWI has advantages over PET-CT in diagnosing malignant from benign lymph nodes of lung cancers.

Diffusion-weighted imaging is superior to positron emission tomography in the detection and nodal assessment of lung cancers.

BACKGROUND: Diffusion-weighted magnetic resonance imaging (DWI) makes it possible to detect malignant tumors based on the difference in the diffusion of water molecules among tissues. The aims of this study are to examine the usefulness of DWI compared with positron emission tomography-computed tomography (PET-CT) in the assessment of lung cancer, and the relationships between the apparent diffusion coefficient (ADC) value and several pathologic factors. METHODS: Sixty-three patients with primary non-small cell lung cancer were enrolled in this study. The DWI and PET-CT were performed before surgery. There were 42 adenocarcinomas, 19 squamous cell carcinomas, and 2 other cell types. RESULTS: Sixty-one lung cancers (97%) were detected visually with DWI. This was significantly higher than 54 lung cancers (86%) with PET-CT. The accuracy for N staging by DWI was 0.81 (51 of 63), which was not significantly higher than 0.71 (45 of 63) by PET-CT. The sensitivity (0.75) for individual metastatic lymph node stations by DWI was significantly higher than that (0.48) by PET-CT. The specificity for individual nonmetastatic lymph node stations was 0.99 by DWI and 0.97 by PET-CT, respectively. The accuracy (0.95) for the diagnosis of lymph node stations by DWI was significantly higher than that (0.90) by PET-CT. There was a weak reverse relationship (correlation coefficient: 0.286) between the ADC value and the maximum standardized uptake value, but no relationship between ADC value and tumor size. The ADC values increased while the cell differentiation increased. CONCLUSIONS: Diffusion-weighted magnetic resonance imaging is superior to PET-CT in the detection of primary lesions and nodal assessment of non-small cell lung cancers.

Clinical and imaging findings of lymphoma in patients with Sjögren syndrome.

OBJECTIVE: To describe and correlate the clinical and imaging findings of lymphomas in patients with Sjögren syndrome. METHODS: The authors reviewed the medical and imaging records of 27 cases of lymphoma from among a total of 463 patients with Sjögren syndrome. The estimated prevalence of lymphoma in patients with Sjögren syndrome was 5.8%. There were 22 women and 5 men. Histopathologically, 26 of the 27 neoplasms were non-Hodgkin lymphoma, including 6 mucosa-associated lymphoid tissue lymphomas, and the other neoplasm was Hodgkin lymphoma. The clinical and imaging findings of lymphomas were analyzed. RESULTS: No obvious correlations were present between the duration or severity of Sjögren syndrome and the lymphoma development. At the initial diagnosis, extranodal involvement was observed in 14 (52%) of the 27 patients, including the salivary gland (n = 9), lacrimal gland (n = 2), lung (n = 2), and thyroid gland (n = 1), mostly in the neck organs. On the other hand, nodal involvement was observed in 21 (78%) of the 27 patients. Of these 21 patients, 19 had at least cervical lymph node involvement. CONCLUSION: Patients with Sjögren syndrome are at increased risk of lymphoma development. Because most lymphomas initially involve the neck organs, including the lymph nodes, meticulous imaging studies mainly focused on the cervical regions are recommended in the follow-up of patients with Sjögren syndrome.