ABSTRACT
<p><b>OBJECTIVE</b>To explore the value of multiple b-value diffusion-weighted imaging (DWI) for differentiation of benign and malignant pulmonary masses.</p><p><b>METHODS</b>Thirty-eight patients were examined by routine sequences and DWI pulse sequence. DWI was acquired through a single-shot echo-planar imaging combined with a respiratory-triggered mode and parallel acquisition. Nine b values ranging from 0 to 1500 s/mm(2) (0, 50, 100, 150, 200, 400, 600, 1000, 1500 s/mm(2)) were used. The intravoxel incoherent motion model was applied to estimate pure diffusion coefficient D, perfusion-related diffusion coefficient D(*), and perfusion fraction f. Mann-Whitney U test was used to compare all measured parameters between benign and malignant groups. The diagnostic performance of the related parameters was evaluated with receiver operating characteristics (ROC) analysis.</p><p><b>RESULTS</b>Of these 38 patients, 30 were pathologically confirmed and 8 were diagnosed based on clinical data. There were 23 lung malignant masses and 15 benign lesions. A significant reduction of D was found in malignant group than in benign group (Z=3.308, P=0.001), while no significant differences in D(*)(Z=1.646, P=0.100) and f(Z=1.254, P=0.210) were observed between the two groups. The area under the ROC curve for D value (0.839) was largest. When the cutoff value was selected as 0.90×10(-3) mm(2)/s, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of diagnosing malignant masses were 95.7%, 80.0%, 90.9%, 91.7%, and 88.9%,respectively.</p><p><b>CONCLUSION</b>The D value in multiple b-value DWI has certain significance in differentiating the benign and malignant pulmonary masses and has the best diagnostic efficiency.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Young Adult , Diffusion Magnetic Resonance Imaging , Methods , Lung Diseases , Diagnosis , Sensitivity and SpecificityABSTRACT
<p><b>OBJECTIVE</b>To explore the image quality of different tube voltage on digital chest radiograph for contrast detail phantom (CDRAD2.0) and occupational exposed workers.</p><p><b>METHODS</b>The CDRAD2.0 phantom DR images of high KV and different tube voltages were analyzed by 3 readers, image quality figure (IQF) were calculated and compared; at the same time 136 exposed workers were examined with high-kV and DR chest radiograph of different tube voltages. Contrast to high-KV images, 10 anatomic sites were scored .The image differences were compared between DR and high-kV.</p><p><b>RESULTS</b>On CDRAD2.0 phantom, the IQF value of DR images in 3 readers were minimum in the condition of 120 kV, average value was 22.25. The analysis of variance in model with random effects, the mean IQF value of different tube voltage DR image had a significant difference (F = 13.775, P<0.01); By Dunnett t-tests analysis, the mean IQF value of DR image in 120 kV and high kilovoltage had no difference (t = -0.58, P = 0.979); On clinical cases, the DR image of 120 kV showed the closest anatomy to the high KV, the mean had no significant difference with 0 (P > 0.05) with single sample t test.</p><p><b>CONCLUSION</b>On the CDRAD2.0 phantom or clinical exposed workers, the DR image quality of 120 kV tube voltage equals to high-KV basically.</p>