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Rationale and Objectives: This study aimed to determine the diagnostic aid of computed tomography (CT) features for the differentiation of active alveolitis and fibrosis using a CT texture analysis (CTTA) prototype and CT densitometry in patients with systemic sclerosis (SSc) using ancillary high-resolution computed tomography (HRCT) features and their longitudinal course as standard of reference.Materials and Methods: We retrospectively analyzed thin-slice noncontrast chest CT image data of 43 patients with SSc (18 men, mean age 51.55 ± 15.52 years; range 23-71 years). All of them had repeated noncontrast enhanced HRCT of the lung. Classification into active alveolitis or fibrosis was done on HRCT based on classical HRCT findings (active alveolitis [19; 44.2%] and fibrosis [24; 55.8%]) and their course at midterm. Results were compared to pulmonary functional tests and were followed up by CT. Ground glass opacity was considered suggestive of alveolitis, whereas coarse reticulation with parenchymal distortion, traction bronchiectasis, and honeycombing were assigned to fibrosis.Results: Statistically significant differences in CTTA were found for first-order textural features (mean intensity, average, deviation, skewness) and second-order statistics (entropy of co-occurrence matrix, mean number of nonuniformity (NGLDM), entropy of NGLDM, entropy of heterogeneity, intensity, and average). Cut-off value for the prediction of fibrosis at baseline was significant for entropy of intensity (P value < .001) and for mean deviation (P value < .001), and for prediction of alveolitis was significant for uniformity of intensity (P value < .001) and for NGLDM (P value < .001). At pulmonary functional tests, forced expiratory volume in 1 second and single-breath diffusion capacity for carbon monoxide were significantly lower in fibrosis than in alveolitis 2.03 ± 0.78 vs. 2.61 ± 0.83, P < .016 and 4.51 ± 1.61 vs. 6.04 ± 1.75, P < .009, respectively. Differences in CT densitometry between alveolitis and fibrosis were not significant.Conclusions: CTTA parameters are significantly different in active alveolitis vs. fibrosis in patients with SSc and may be helpful for differentiation of these two entities. [ABSTRACT FROM AUTHOR]

Rationale and Objectives To evaluate the performance of a dedicated computed tomography (CT) software called “bone reading” generating rib unfolded images for improved detection of rib metastases in patients with lung cancer in comparison to readings of 5- and 1-mm axial CT images and 18 F-Fluordeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT). Materials and Methods Ninety consecutive patients who underwent 18 F-FDG-PET/CT and chest CT scanning between 2012 and 2014 at our institution were analyzed retrospectively. Chest CT scans with 5- and 1-mm slice thickness were interpreted blindly and separately focused on the detection of rib metastases (location, number, cortical vs. medullary, and osteoblastic vs. sclerotic). Subsequent image analysis of unfolded 1 mm–based CT rib images was performed. For all three data sets the reading time was registered. Finally, results were compared to those of FDG-PET. Validation was based on FDG-PET positivity for osteolytic and mixed osteolytic/osteoblastic focal rib lesions and follow-up for sclerotic PET-negative lesions. Results A total of 47 metastatic rib lesions were found on FDG-PET/CT plus another 30 detected by CT bone reading and confirmed by follow-up CT. Twenty-nine lesions were osteolytic, 14 were mixed osteolytic/osteoblastic, and 34 were sclerotic. On a patient-based analysis, CT (5 mm), CT (1 mm), and CT (1-mm bone reading) yielded a sensitivity, specificity, and accuracy of 76.5/97.3/93, 81.3/97.3/94, and 88.2/95.9/92, respectively. On segment-based (unfolded rib) analysis, the sensitivity, specificity, and accuracy of the three evaluations were 47.7/95.7/67, 59.5/95.8/77, and 94.8/88.2/92, respectively. Reading time for 5 mm/1 mm axial images and unfolded images was 40.5/50.7/21.56 seconds, respectively. Conclusions The use of unfolded rib images in patients with lung cancer improves sensitivity and specificity of rib metastasis detection in comparison to 5- and 1-mm CT slice reading. Moreover, it may reduce the reading time. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: This study determines the value of whole brain color-coded three-dimensional perfused blood volume (PBV) computed tomography (CT) for the visualization of the infarcted tissue in acute stroke patients. Materials and Methods: Nonenhanced CT (NECT), perfusion CT (PCT), and CT angiography (CTA) in 48 patients with acute ischemic stroke were performed. Whole brain PBV was calculated from NECT and CTA data sets using commercial software. PBV slices in identical orientation to the PCT slices were reconstructed and the area of visual perfusion abnormality on PBV maps was measured. The infarct core in the corresponding PCT slices (CBV <2.0 mL/100 g) was measured automatically with commercial software. The ischemic area on PBV and the infarct core on quantitative PCT were compared using the Pearsons-R correlation coefficient. Significance was considered for P < .05. Results: The quantitative PCT demonstrated a mean infarct core volume of 35.48 +/- 32.17 cm(3), whereas the volume of visual perfusion abnormality of the corresponding PBV slices was 37.16 +/- 37.59 cm(3). The perfusion abnormality in PBV was highly correlated with the infarct core of quantitative PCT for area per slice (r = 0.933, P < .01) as well as volume (r = 0.922, P < .01). Conclusions: PBV can serve as surrogate marker corresponding to the infarct core in acute stroke with whole brain coverage. [ABSTRACT FROM AUTHOR]

Rationale and Objectives: This study determines the value of whole brain color-coded three-dimensional perfused blood volume (PBV) computed tomography (CT) for the visualization of the infarcted tissue in acute stroke patients. Materials and Methods: Nonenhanced CT (NECT), perfusion CT (PCT), and CT angiography (CTA) in 48 patients with acute ischemic stroke were performed. Whole brain PBV was calculated from NECT and CTA data sets using commercial software. PBV slices in identical orientation to the PCT slices were reconstructed and the area of visual perfusion abnormality on PBV maps was measured. The infarct core in the corresponding PCT slices (CBV <2.0 mL/100 g) was measured automatically with commercial software. The ischemic area on PBV and the infarct core on quantitative PCT were compared using the Pearsons-R correlation coefficient. Significance was considered for P < .05. Results: The quantitative PCT demonstrated a mean infarct core volume of 35.48 ± 32.17 cm3, whereas the volume of visual perfusion abnormality of the corresponding PBV slices was 37.16 ± 37.59 cm3. The perfusion abnormality in PBV was highly correlated with the infarct core of quantitative PCT for area per slice (r = 0.933, P < .01) as well as volume (r = 0.922, P < .01). Conclusions: PBV can serve as surrogate marker corresponding to the infarct core in acute stroke with whole brain coverage. [Copyright &y& Elsevier]

Computed tomography (CT) has become an increasingly accepted technique and is the method of choice for direct visualization of pulmonary emboli (PE). The quantitative assessment of tissue perfusion may yield more important information for patient management than the direct visualization of emboli by CT alone. Several attempts have been made to measure pulmonary blood flow by administration of intravenous contrast material. In this article, various experimental CT approaches for visualization and quantification of pulmonary perfusion are discussed. Ideally, CT will be able to provide both structural and functional information. Simple measurement of lung density before and after intravenous contrast delivery has been performed with single-slice CT technology using region-of-interest methodology. For electron-beam CT, a repeated data acquisition on a 7.6-cm lung volume has proven to be technically feasible. Using such dynamic scanning, reduced blood flow was observed in occluded lung segments. Color-encoded parenchymal density distribution in the axial, coronal, and sagittal planes was derived from thin collimation data sets using four-row multi-slice spiral CT (MSCT). Initial animal data from 16-slice MSCT offer a real CT-subtraction technique of the entire chest for the first time. [Copyright &y& Elsevier]