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ABSTRACT: To evaluate image quality of dual-source computed tomography (CT) angiograms acquired with high temporal resolution and high pitch modes.
Two groups of 70 consecutive patients underwent chest CT angiography with dual-source, single-energy CT, with an 83-ms temporal resolution and a pitch of 2 (group 1) or a pitch of 3 (group 2). Subjective and objective image quality and the diagnostic value were assessed by two radiologists in consensus. The radiation dose was recorded.
The image quality was always diagnostic in both groups, rated as excellent in 97% of group 1 (68/70) and 98.5% of group 2 (69/70) examinations. Although no statistically significant difference in subjective image noise was found between the two groups (p = 0.3055), objective noise was found to be statistically higher in group 2 (p < 0.0001). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were found to be significantly higher in group 1 than in group 2 (p = 0.0014). The acquisition time was significantly shorter in group 2 than in group 1 (p < 0.0001). The dose-length product was significantly lower in group 2 than in group 1 (p < 0.0001).
High temporal resolution and high pitch modes provided standard CT angiographic examinations of excellent quality for thoracic applications in routine clinical practice.
European Radiology 11/2009; 20(5):1188-96. · 3.22 Impact Factor
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ABSTRACT: To compare peripheral pulmonary artery image quality at 80 kVp and 140 kVp in the same patients.
Image quality of third-, fourth- and fifth-order arteries was assessed at 80 kV and 140 kV on 1-mm-thick transverse scans, generated from dual-source computed tomography (CT) acquisitions.
The mean level of enhancement was significantly higher at 80 kV compared with 140 kV for the third-, fourth-, and fifth-order arteries (P < 0.0001). Despite a higher noise level at 80 kV (P < 0.0001), the signal-to-noise ratio and contrast-to-noise ratio were significantly higher at 80 kV than at 140 kV at the level of third-, fourth-, and fifth-order arteries (P < 0.0001). The mean vascular attenuation, mean signal-to-noise ratio and contrast-to-noise ratio for peripheral arteries were significantly superior at 80 kV in the 3 body mass index categories (P < 0.005).
Eighty-kilovolt protocols significantly improve the image quality of peripheral pulmonary arteries on CT angiograms of the chest.
Journal of computer assisted tomography 10/2009; 33(6):981-6. · 1.38 Impact Factor
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ABSTRACT: The purpose of the study was to assess pulmonary perfusion on a lobar level in smokers using dual-energy computed tomography (CT). Forty-seven smokers and ten non-smokers underwent a dual-energy multi-detector CT angiogram of the chest that allowed automatic quantification of emphysema and determination of the iodine content at the level of the microcirculation (i.e. "perfusion imaging"). Emphysema was present in 37 smokers and absent in ten smokers. Smokers with an upper lobe predominance of emphysema (n = 8) had: (1) significantly lower attenuation enhancement values in the upper lobes compared with smokers without emphysema; (2) the lobes with the most severe emphysematous changes had a statistically significantly higher percentage of emphysema (p = 0.0001) and lower mean attenuation enhancement values (p = 0.0001) than the ipsilateral lobes with less severe emphysema, matching parenchymal destruction; (3) a correlation was found between the difference in percentage of emphysema between the upper and lower lobes and the difference in attenuation attenuation enhancement values in the corresponding lobes (p = 0.0355; r = -0.54). Regional alterations of lung perfusion can be depicted by dual-energy CT in smokers with predominant emphysema.
European Radiology 07/2009; 19(12):2834-43. · 3.22 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the accuracy of 3-mm-thick reconstructed sections in the diagnosis of bronchiectasis with multislice CT (MSCT). Forty consecutive patients suspected of bronchiectasis (23 females, 17 males; mean age 51 years) underwent MSCT of the entire thorax with a 4x1-mm collimation (120 kV, 0.5 s/rotation, 80 mAs/slice) and a pitch of 1.75. From each data set (mean z-axis coverage: 257 mm; mean duration: 21 s), two series of images were systematically generated: 1-mm (group 1) and 3-mm (group 2)-thick reconstructed scans. Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial-frequency algorithm. Two observers independently analyzed the presence of bronchiectasis and associated abnormalities in group-1 and group-2 lung images. No significant difference between group 1 and group 2 was found in: (a) the detection of bronchiectasis, identified in 24 patients (60%) in group 1 and in 23 patients (57.5%) in group 2 ( p=0.08); (b) the evaluation of the extent of bronchiectasis, identifying focal bronchiectasis in 10 patients (25%) in group 1 and 7 patients (17.5%) in group 2 ( p=0.39) and multifocal bronchiectasis in 16 patients (40%) in both groups; (c) the characterisation of bronchiectasis (cylindral bronchiectasis: group 1, n=24, 60%; group 2, n=21, 53%, p=0.08); varicose bronchiectasis: group 1, n=5, 12.5%; group 2, n=6, 15%, p=0.56); and cystic bronchiectasis: group 1, n=2, 5%; group 2, n=2, 5%). Apart from the identification of abnormal bronchial wall thickening (group 2, n=35, 87.5%, vs group 1, n=31, 77.5%, p<0.05), recognition of associated bronchopulmonary anomalies did not differ between the two groups. This study demonstrates a comparable accuracy of the 3- and 1-mm-thick reconstructed scans in the detection and characterization of bronchiectasis. These results suggest the potential usefulness of 3-mm-thick scans generated from 4x2.5-mm acquisitions in the screening of bronchiectasis, which would allow a 20% radiation dose reduction compared with the present investigation.
European Radiology 05/2003; 13(5):1165-71. · 3.22 Impact Factor
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ABSTRACT: The purpose of this study was to investigate whether the severity of acute pulmonary embolism (PE) could be quantitatively assessed with spiral CT angiography (SCTA). Thirty-six consecutive patients without underlying cardiopulmonary disease and high clinical suspicion of PE underwent prospectively thin-collimation SCTA and echocardiography at the time of the initial diagnosis (T0) and after initial therapy (T1; mean interval of time T1-T2: 32 days). The CT severity score was based on the percentage of obstructed surface of each central and peripheral pulmonary arterial section using a 5-point scale (1: <25%; 2: 25-49%; 3: 50-74%; 4: 75-99%; 5: 100%). The sum of the detailed scores attributed to 5 mediastinal, 6 lobar and 20 segmental arteries per patient led to the determination of central, peripheral and global CT severity scores and subsequent determination of percentages of obstruction of the pulmonary circulation. Echocardiographic severity criteria included the presence of signs of acute cor pulmonale and/or systolic pulmonary hypertension (>40 mm Hg). The SCTA depicted acute PE in all patients at T0 with complete resolution of endovascular clots in 10 patients at T1. At T0, the mean percentage of obstruction of the pulmonary arterial bed was significantly higher in the 22 patients with echocardiographic signs of severity (56+/-13 vs 28+/-32%; p<0.001). A significant reduction in the mean percentage of pulmonary artery obstruction was observed in the 19 patients with resolution of echocardiographic criteria of severity between T0 and T1 T0: 57+/-14%; T1: 7+/-11%; p<0.001). The threshold value for severe PE on CT angiograms was 49% (sensitivity: 0.773; specificity: 0.214). The mean (+/-SD) pulmonary artery pressure was significantly higher in the 26 patients with more than 50% obstruction of the pulmonary artery bed (45+/-15 mm Hg) than in the 10 patients with less than 50% obstruction of pulmonary artery bed at T0 (31+/-11 mm Hg; p<0.01). The CT severity score evaluated in the present study enables quantitative assessment of acute PE severity on spiral CT angiograms, readily applicable in routine clinical practice.
European Radiology 01/2003; 13(1):29-35. · 3.22 Impact Factor
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ABSTRACT: Our objective was to evaluate the impact of multislice CT (MSCT) on image quality and diagnostic value of spiral CT angiograms. Over an 8-month period (January 2000 to August 2000), 134 consecutive patients, including 55 patients with underlying lung disease, underwent MSCT (group 1). Image quality and diagnostic results of CT angiograms were compared with those obtained in 125 consecutive patients, including 58 patients with underlying lung disease, evaluated with thin-collimation single slice CT (SSCT; group 2) over a similar period of time (January 1999 to August 1999). A 3-month clinical follow-up was systematically obtained in all patients who were not anticoagulated in the two groups. For a significantly longer mean z-axis coverage, the mean duration of data acquisition was significantly shorter with MSCT. The frequency of examinations devoid of motion artifacts was significantly higher in group 1 than in group 2. In the absence of significant difference in the quality of vascular enhancement, mainly coded as good or excellent, the proportion of examinations interpretable down to the subsegmental arteries was higher in group 1 (57.5%) than in group 2 (13%) ( p<0.0001). The benefits of MSCT were more marked for patients with underlying respiratory disease and did not lead to a higher detection rate of peripheral pulmonary embolism. The negative predictive values of single-slice and multislice CT were 100 and 99%, respectively. Improvement in image quality on MSCT scans accounts for the improved diagnostic accuracy of CT angiography, in particular for patients with impaired respiratory function.
European Radiology 08/2002; 12(8):1971-8. · 3.22 Impact Factor
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ABSTRACT: Our objective was to evaluate the impact of multislice CT (MSCT) on image quality and diagnostic value of spiral CT angiograms.
Over an 8-month period (January 2000 to August 2000), 134 consecutive patients, including 55 patients with underlying lung
disease, underwent MSCT (group 1). Image quality and diagnostic results of CT angiograms were compared with those obtained
in 125 consecutive patients, including 58 patients with underlying lung disease, evaluated with thin-collimation single slice
CT (SSCT; group 2) over a similar period of time (January 1999 to August 1999). A 3-month clinical follow-up was systematically
obtained in all patients who were not anticoagulated in the two groups. For a significantly longer mean z-axis coverage, the
mean duration of data acquisition was significantly shorter with MSCT. The frequency of examinations devoid of motion artifacts
was significantly higher in group 1 than in group 2. In the absence of significant difference in the quality of vascular enhancement,
mainly coded as good or excellent, the proportion of examinations interpretable down to the subsegmental arteries was higher
in group 1 (57.5%) than in group 2 (13%) (p<0.0001). The benefits of MSCT were more marked for patients with underlying respiratory disease and did not lead to a higher
detection rate of peripheral pulmonary embolism. The negative predictive values of single-slice and multislice CT were 100
and 99%, respectively. Improvement in image quality on MSCT scans accounts for the improved diagnostic accuracy of CT angiography,
in particular for patients with impaired respiratory function.
European Radiology 07/2002; 12(8):1971-1978. · 3.22 Impact Factor
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ABSTRACT: To evaluate the diagnostic accuracy of coronal thin sections as an alternative to transverse high-resolution computed tomography (HRCT) scans in the diagnostic approach to infiltrative lung disease (ILD) with multislice computed tomography (MSCT).
Fifty consecutive patients referred for suspicion of ILD underwent MSCT (collimation: 4 mm x 1 mm; pitch: 1.75; scan time: 0.5 seconds; 80 mA per slice) of the entire thorax. Two sets of lung images were systematically reconstructed: 1-mm thick transverse computed tomography (CT) scans (i.e., HRCT scans) (group 1) and 1-mm thick coronal images (group 2). Both series of images were obtained at 10-mm intervals and reconstructed with a high-spatial frequency algorithm. Two observers independently analyzed the overall image quality, the presence and distribution of CT features of ILD, and the diagnostic value of group 1 and group 2 lung images.
Group 1 and group 2 images were coded as interpretable, with minimal respiratory artifacts in the lower lung zones in two cases (4%). Presence of abnormal lung infiltration was found in 38 patients in group 2 with concordant interpretation of group 1 images. No significant difference was found in the identification of CT features of ILD between group 2 and group 1 (nodules: 32% vs. 30%; lines: 14% vs. 16%; increased attenuation: 24% vs. 26%; fibrosis: 48% vs. 50%; distortion: 46% vs. 50%; and abnormal interfaces: 16% in both groups). Distribution of lung abnormalities in central, peripheral, anterior, and/or posterior lung zones was similarly recognized in group 2 and group 1. In patients with extensive lung infiltration, the vertical predominance of lung changes was more precisely assessed in group 2 (n = 12) than in group 1 (n = 4). For a mean coverage of 260 mm in this study group, the mean number of sections to be interpreted was significantly lower in group 2 (19 sections) than in group 1 (28 sections) (P < 0.01).
Coronal sections allow a diagnostic approach to ILD as precise as that provided with HRCT scans, based on the interpretation of a significantly reduced number of images.
Journal of Computer Assisted Tomography 27(2):266-73. · 1.22 Impact Factor
