Diffusion-weighted imaging vs STIR turbo SE imaging: capability for quantitative differentiation of small-cell lung cancer from non-small-cell lung cancer.

OBJECTIVE: To compare the capability of differentiation of small-cell lung cancer (SCLC) from non-SCLC (NSCLC) between diffusion-weighted imaging (DWI) and short tau inversion recovery (STIR) turbo spin-echo imaging. METHODS: The institutional review board of Kobe University Hospital, Kobe, Japan, approved this study, and written informed consent was obtained from each patient. 49 patients with NSCLC (30 males and 19 females; mean age, 66.8 years) and 7 patients with SCLC (5 males and 2 females; mean age, 68.6 years) enrolled and underwent DWI and STIR. To quantitatively differentiate SCLC from NSCLC, apparent diffusion coefficient (ADC) values on DWI and contrast ratios (CRs) between cancer and muscle on STIR were evaluated. ADC values and CRs were then compared between the two cell types by Mann-Whitney's U-tests, and the diagnostic performances were compared by McNemar's test. RESULTS: There were significant differences of mean ADC values (p < 0.001) and mean CRs (p = 0.003). With adopted threshold values, the specificity (85.7%) and accuracy (85.7%) of DWI were higher than those of STIR (specificity, 63.3%; p = 0.001 and accuracy, 66.1%; p = 0.001). In addition, the accuracy of combination of both indexes (94.6%; p = 0.04) could significantly improve as compared with DWI alone. CONCLUSION: DWI is more useful for the differentiation of SCLC from NSCLC than STIR, and their combination can significantly improve the accuracy in this setting. ADVANCES IN KNOWLEDGE: Pulmonary MRI, including DWI and STIR, had a potential of the suggestion of the possibility as SCLC.

Three-dimensional airway lumen volumetry: comparison with bronchial wall area and parenchymal densitometry in assessment of airway obstruction in pulmonary emphysema.

OBJECTIVES: The purpose of this study was to compare three-dimensional airway lumen volumetry with bronchial wall area and parenchymal densitometry in the assessment of airway obstruction in pulmonary emphysema. METHODS: 56 patients, who were smokers, underwent CT examination and pulmonary function tests (PFTs). For quantitative assessments, the following parameters were computationally calculated: (1) percentage of voxels -950, -960 and -970 HU in the lung (%LAA(-950), %LAA(-960) and %LAA(-970), respectively); (2) percentage of partial bronchi luminal volumes per total luminal volumes (LV(main), main and distal bronchial volume/total luminal volume; LV(lobe), lobar and distal bronchial volume/total luminal volume); and (3) mean wall area percentages of segmental bronchi of the right apical and left apicoposterior segment (WA%(seg)) and of subsegmental bronchi (WA%(sub)) in the upper lobes. These parameters were correlated with PFTs and statistically compared between a chronic obstructive pulmonary disease (COPD) group [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)<70] and a non-COPD group. RESULTS: FEV1, maximum mid-expiratory flow rate and forced expiratory flow at 25% vital capacity had significant correlation with LV(main) (r>0.53, p<0.0001), LV(lobe) (r>0.52, p<0.0001), WA%(seg) (|r|>0.29, p<0.05) and WA%(sub) (|r|>0.31, p<0.05). FEV1/FVC had significant correlation with all parameters (0.27<|r|<0.52, p<0.05). LV(main) and LV(lobe) and WA%(seg) and WA%(sub) were significantly different between the two groups (LV(main) and LV(lobe); p<0.0001, WA%(seg) and WA%(sub); p<0.05). CONCLUSIONS: Bronchial luminal volumetric assessment better reflected the airflow limitation parameters. ADVANCES IN KNOWLEDGE: Bronchial luminal volumetric assessment can potentially be used to gauge airflow limitation in pulmonary emphysema.

Oxygen-enhanced MR ventilation imaging of the lung: preliminary clinical experience in 25 subjects.

OBJECTIVE: The purpose of this study was to show the feasibility of oxygen-enhanced MR ventilation imaging in a clinical setting with correlation to standard pulmonary function tests, high-resolution CT, and (81m)Kr ventilation scintigraphy. SUBJECTS AND METHODS: Seven healthy volunteers, 10 lung cancer patients, and eight lung cancer patients with pulmonary emphysema were studied. A respiratory synchronized inversion-recovery single-shot turbo-spin-echo sequence (TE, 16; inversion time, 720 msec; interecho spacing, 4 msec) was used for data acquisition. The following paradigm of oxygen inhalation was used: 21% oxygen (room air), 100% oxygen, 21% oxygen. MR imaging data including maximum mean relative enhancement ratio and mean slope of relative enhancement were correlated with forced expiratory volume in 1 sec, diffusing lung capacity, high-resolution CT emphysema score, and mean distribution ratio of (81m)Kr ventilation scintigraphy. RESULTS: Oxygen-enhanced MR ventilation images were obtained in all subjects. Maximum mean relative enhancement ratio and mean slope of relative enhancement of lung cancer patients were significantly decreased compared with those of the healthy volunteers (p < 0.0001, p < 0.0001). The mean slope of relative enhancement in lung cancer patients with pulmonary emphysema was significantly lower than that of lung cancer patients without pulmonary emphysema (p < 0.0001). Maximum mean relative enhancement ratio (r(2) = 0.81) was excellently correlated with diffusing lung capacity. Mean slope of relative enhancement (r(2) = 0.74) was strongly correlated with forced expiratory volume in 1 sec. Maximum mean relative enhancement had good correlation with the high-resolution CT emphysema score (r(2) = 0.38). The maximum mean relative enhancement had a strong correlation with the distribution ratio (r(2) = 0.77). CONCLUSION: Oxygen-enhanced MR ventilation imaging in human subjects showed regional changes in ventilation, thus reflecting regional lung function.