Standard Chest Computed Tomography Research Articles

Coronary artery calcification scoring system based on the coronary artery calcium data and reporting system (CAC-DRS) predicts major adverse cardiovascular events or all-cause death in patients with potentially curable lung cancer without a history of cardiovascular disease.

The coronary artery calcium data and reporting system (CAC-DRS) is a novel reporting system based on CAC severity. Lung cancer patients have a high risk of cardiovascular disease (CVD), for which CAC severity may provide additional prognostic information. Using non-gated, non-contrast computed tomography (CT), we evaluated the CAC-DRS for predicting CVD and all-cause death in patients with potentially curable resected lung cancer. We retrospectively studied 309 consecutive patients without a history of CVD (mean age 67.4 ± 8.2years, 61% male) who underwent curative surgery for non-small-cell lung cancer between May 2012 and March 2019 at the Japanese Red Cross Okayama Hospital. Time to incidence of major adverse cardiac events (MACEs) (non-fatal myocardial infarction, non-fatal stroke and cardiovascular death) and all-cause death was analyzed using Fine and Gray and Cox regression models. The CAC-DRS score was assessed using standard chest CT without electrocardiogram gating. During 52-months' median follow-up, 43 patients (13.4%) developed incident MACEs or died from any cause; the pathological cancer stages were Ia (n = 20), Ib (n = 8), IIa (n = 2), IIb (n = 2) and IIIa (n = 11). Patients had a graded increase in incidence of MACEs or all-cause death with increasing categories of CAC-DRS. The CAC-DRS score was significantly associated with incident MACEs or all-cause death after adjusting for confounding factors (hazard ratio 1.18; 95% confidence interval 1.10-1.25, p < 0.01). In conclusion, the CAC-DRS score on non-gated standard CT can predict incident MACEs and/or all-cause death in patients with potentially curable resected lung cancer. Lung cancer survivors with a greater CAC-DRS category may need more active management of cardiovascular risk factors.

Low Thoracic Skeletal Muscle Area Predicts Morbidity After Pneumonectomy for Lung Cancer

Sarcopenia represented by low psoas muscle area is associated with increased hospital length of stay (LOS), postoperative complications, and mortality. We studied whether thoracic skeletal muscle area(TSMA) derived from computed tomography (CT) predicts morbidity after pneumonectomy for lung cancer. Consecutive patients who underwent pneumonectomy for lung cancer from 2005 to 2017 were retrospectively analyzed. TSMA was defined as the sum of muscle area at the level of the eighth and the 12ththoracic vertebral bodies on preoperative CT. Patientswere stratified into sex-specific TSMA quartiles for univariate time-to-event analyses. The effect of continuous TSMA measurements on operative complications, hospital and intensive care unit (ICU) LOS, discharge disposition, and hospital readmission within 90 days was estimated using multivariable models adjusted for age, sex, body mass index, forced expiratory volume in 1 second, Zubrod score, and pneumonectomy type. Standard (n= 102, 78.5%) or high-risk (n= 28, 21.5%; extrapleural: n= 3, 2.3%; carinal: n= 9, 6.9%; completion: n= 16, 12.3%) pneumonectomy was performed in 130 patients (60.8 ± 10.6 years; 43.1% women). Major complications occurred in 33.1% (n= 43 of 130) and readmission in 17.7% (n= 23 of 130) of patients. In multivariable models, patients with high TSMA experienced fewer overall (odds ratio [OR], 0.87; P= .04) and cardiopulmonary (OR, 0.86; P= .04) complications, and fewer readmissions (OR, 0.78; P= .01). Associations with ICU LOS (hazard ratio, 1.08; P= .051) and hospital LOS (hazard ratio, 1.05; P= .18) did not reach significance. TSMA predicts adverse outcome after pneumonectomy for lung cancer. This marker, readily derived from standard chest CT, identifies patients at increased risk for postoperative complications and may help select patients appropriate for focused rehabilitation before pneumonectomy.

Volumetric assessment of solid pulmonary nodules on ultralow-dose CT: a phantom study.

To reduce the radiation exposure from chest computed tomography (CT), ultralow-dose CT (ULDCT) protocols performed at sub-millisievert levels were previously tested for the evaluation of pulmonary nodules (PNs). The purpose of our study was to investigate the effect of ULDCT and iterative image reconstruction on volumetric measurements of solid PNs. CT datasets of an anthropomorphic chest phantom containing solid microspheres were obtained with a third-generation dual-source CT at standard dose, 1/8th, 1/20th and 1/70th of standard dose [CT volume dose index (CTDIvol): 0.03-2.03 mGy]. Semi-automated volumetric measurements were performed on CT datasets reconstructed with filtered back projection (FBP) and advanced modelled iterative reconstruction (ADMIRE), at strength level 3 and 5. Absolute percentage error (APE) evaluated measurement accuracy related to the effective volume. Scan repetition differences were evaluated using Bland-Altman analysis. Two-way analysis of variance (ANOVA) assessed influence of different scan parameters on APE. Proportional differences (PDs) tested the effect of dose settings and reconstruction algorithms on volumetric measurements, as compared to the standard protocol (standard dose-FBP). Bland-Altman analysis revealed small mean interscan differences of APE with narrow limits of agreement (-0.1%±4.3% to -0.3%±3.8%). Dose settings (P<0.001), reconstruction algorithms (P<0.001), nodule diameters (P<0.001) and nodule density (P=0.011) had statistically significant influence on APE. Post-hoc Bonferroni tests showed slightly higher APE when scanning with 1/70th of standard dose [mean difference: 3.4%, 95% confidence interval (CI): 2.5-4.3%; P<0.001], and for image reconstruction with ADMIRE5 (mean difference: 1.8%, 95% CI: 1.0-2.5%; P<0.001). No significant differences for scanning with 1/20th of standard dose (P=0.42), and image reconstruction with ADMIRE3 (P=0.19) were found. Scanning with 1/70th of standard dose and image reconstruction with FBP showed the widest range of PDs (-16.8% to 23.4%) compared to standard dose-FBP. Our phantom study showed no significant difference between nodule volume measurements on standard dose CT (CTDIvol: 2 mGy) and ULDCT with 1/20th of standard dose (CTDIvol: 0.10 mGy).

Estimating the Patient-specific Dose to the Thyroid and Breasts and Overall Risk in Chest CT When Using Organ-based Tube Current Modulation.

Purpose To assess the potential dose reduction to the thyroid and breasts in chest computed tomography (CT) with organ-based tube current modulation (OBTCM). Materials and Methods In this retrospective study (from January 2015 to December 2016), the location of the breasts with respect to the reduced tube current zone was determined. With Monte Carlo simulations, patient-specific dose distributions of chest CT scans were calculated for 50 female patients (mean age, 53.7 years ± 17.5; range, 20-80 years). The potential dose reduction with OBTCM was assessed. In addition, simulations of clinical OBTCM scans were made for 17 of the 50 female patients (mean age, 43.8 years ± 17.1; range, 20-69 years). Posterior organs in the field of view were analyzed and lifetime attributable risk (LAR) of cancer incidence and mortality was estimated. Image quality between standard CT and OBTCM scans was compared. Results No women had all breast tissue within the reduced tube current zone. Dose reductions of 18% in the thyroid and 9% in the breasts were observed, whereas the doses in lung, liver, and kidney were 17%, 11%, and 26% higher. Overall, the LAR for cancer incidence was not significantly different between conventional and OBTCM scanning (P = .06). Image quality improved with OBTCM (P < .002). Conclusion The potential benefit of OBTCM to the female breast in chest CT is overestimated because of a limited reduced tube current zone; despite a 9% dose reduction to the female breast, posterior organs will absorb up to 26% more radiation, resulting in no reduction in radiation-induced malignancies. © RSNA, 2018.

Computer-aided detection (CAD) of solid pulmonary nodules in chest x-ray equivalent ultralow dose chest CT - first in-vivo results at dose levels of 0.13 mSv

ObjectivesTo determine the value of computer-aided detection (CAD) for solid pulmonary nodules in ultralow radiation dose single-energy computed tomography (CT) of the chest using third-generation dual-source CT at 100kV and fixed tube current at 70 mAs with tin filtration. Methods202 consecutive patients undergoing clinically indicated standard dose chest CT (1.8±0.7 mSv) were prospectively included and scanned with an additional ultralow dose CT (0.13±0.01 mSv) in the same session. Standard of reference (SOR) was established by consensus reading of standard dose CT by two radiologists. CAD was performed in standard dose and ultralow dose CT with two different reconstruction kernels. CAD detection rate of nodules was evaluated including subgroups of different nodule sizes (<5, 5–7, >7mm). Sensitivity was further analysed in multivariable mixed effects logistic regression. ResultsThe SOR included 279 solid nodules (mean diameter 4.3±3.4mm, range 1–24mm). There was no significant difference in per–nodule sensitivity of CAD in standard dose with 70% compared to 68% in ultralow dose CT both overall and in different size subgroups (all p>0.05). CAD led to a significant increase of sensitivity for both radiologists reading the ultralow dose CT scans (all p<0.001). In multivariable analysis, the use of CAD (p<0.001), and nodule size (p<0.0001) were independent predictors for nodule detection, but not BMI (p=0.933) and the use of contrast agents (p=0.176). ConclusionsComputer-aided detection of solid pulmonary nodules using ultralow dose CT with chest X-ray equivalent radiation dose has similar sensitivities to those from standard dose CT. Adding CAD in ultralow dose CT significantly improves the sensitivity of radiologists.

CAC Scores from Standard Chest Scans Can Predict All-Cause Mortality

Coronary artery calcification (CAC) provides useful prognostic information that is typically quantified on a dedicated 3-mm-slice computed tomography (CT) scan gated to electrocardiography (ECG). CAC scores can also be calculated from standard chest CTs, ordered for numerous clinical indications, which use wider cuts (typically, 6 mm) without ECG gating. To ascertain the prognostic usefulness of CAC scores calculated from …

Relationship of Coronary Calcium on Standard Chest CT Scans With Mortality

ObjectivesThe aim of this study was to determine the correlation between coronary artery calcium (CAC) scores on 3 mm electrocardiography (ECG)-gated computed tomography (CT) scans and standard 6 mm chest CT scans, and to compare relative strength of associations of CAC on each scan type with mortality risk. BackgroundCoronary artery calcification predicts cardiovascular disease (CVD) and all-cause mortality, and is typically measured on ECG-gated 3 mm CT scans. Patients undergo standard 6 mm chest CTs for various clinical indications much more frequently, but CAC is not usually quantified. To better understand the usefulness of standard chest CTs to quantify CAC, we conducted a case-control study among persons who had both scan types. MethodsBetween 2000 and 2003, 4,544 community-living individuals self- or physician-referred for “whole-body” CT scans, had 3 mm ECG-gated CTs and standard 6 mm chest CTs, and were followed for mortality through 2009. In this nested case-control study, we identified 157 deaths and 494 controls frequency matched (1:3) on age and sex. The Agatston method quantified CAC on both scan types. Unconditional logistic regression determined associations with mortality, accounting for CVD risk factors. ResultsParticipants were 68 ± 11 years of age and 63% male. The Spearman correlation of CAC scores between the 2 scan types was 0.93 (p < 0.001); median CAC scores were lower on 6 mm CTs compared to 3 mm CTs (22 vs.104 Agatston units, p < 0.001). Adjusted for traditional CVD risk factors, each standard deviation higher CAC score on 6 mm CTs was associated with 50% higher odds of death (odds ratio: 1.5; 95% confidence interval: 1.2 to 1.9), similar to 50% higher odds on the 3 mm ECG-gated CTs (odds ratio: 1.5; 95% confidence interval: 1.1 to 1.9). ConclusionsCAC scores on standard 6 mm chest CTs are strongly correlated with 3 mm ECG-gated CTs and similarly predict mortality in community-living individuals. Chest CTs performed for other clinical indications may provide an untapped resource to garner CVD risk information without additional radiation exposure or expense.

Evaluation of pulmonary nodules and infection on chest CT with radiation dose equivalent to chest radiography: Prospective intra-individual comparison study to standard dose CT

PurposeTo compare prospectively, in patients undergoing chest computed tomography (CT) for pulmonary-nodules or infection, image-quality and accuracy of standard dose (SD) and reduced dose (RD) CT with tin-filtration. Material and methodsThis IRB-approved study included 100 consecutive patients (36 female;median age 56 years) referred for follow-up of pulmonary-nodules (n=43) or suspicion of infection (n=57) undergoing single-energy CT with SD and RD using tin-filtration at 100kVp (CTDIvol 2.47mGy and 0.07mGy, respectively). Images were reconstructed with advanced modeled iterative reconstruction (ADMIRE) at strength 3 and 5. Image-noise was measured. Two independent readers evaluated nodules and pulmonary-infection. SD CT served as reference standard. ResultsNo significant difference was found in noise between RD with ADMIRE5 and SD with ADMIRE3 (118HU±14 vs. 120HU±17; p=0.08). Sensitivity for detection of atelectasis and interstitial lung changes was higher in images reconstructed with ADMIRE5 (93% and 88%; respectively) than in those reconstructed with ADIMRE3 (77% and 78%; respectively). Sensitivity for detection of consolidations was 90% for ADMIRE3 and 89% for ADMIRE5. Sensitivity for nodule detection was 71% for ADMIRE3 and 81% for ADMIRE5. Specificity for detection of atelectasis and interstitial lung changes was 99% and 96% with ADMIRE5 and 99% and 96% with ADMIRE3. Specificity for detection of consolidations was 99% for ADMIRE3 and 5. Specificity for detection of nodules was 87% for both ADMIRE3 and 5. ConclusionChest CT with a radiation dose equivalent to conventional radiography is feasible and allows for detection of pulmonary infection with high sensitivity, whereas the accuracy for detecting nodules is only moderate.

Under-reporting of cardiovascular findings on chest CT.

It is unclear whether (and, to what extent) radiologists look at and report cardiovascular abnormalities on non-cardio-synchronized standard chest computed tomography (CT). In this study, the frequency and the reporting rate of cardiovascular findings in chest CT examinations were retrospectively assessed. This study was approved by the institutional review board of each participating center. Four academic centers provided data on 447 subjects who underwent non-ECG-synchronized chest CT examinations for evaluating pulmonary fibrosis (161/447, 36%), suspected pulmonary embolism (140/447, 31.3%), or lung cancer staging (146/447, 32.7%). A total of 220/447 (53.7%) and 227/447 CT (46.3%) examinations were evaluated and reported by junior and senior chest radiologists, respectively. Two radiologists with training in cardiac imaging reviewed the same chest CT images looking for the presence of incidental cardiovascular abnormalities using a preformatted score sheet. Inter-observer agreement was assessed using the kappa coefficient of agreement (k). Inter-observer agreement between the study reviewers was moderate to good (0.4-0.73) for most of the incidental cardiovascular findings. At least one incidental cardiovascular finding not documented in the original report was identified by the study reviewers in 225/409 (55%) of chest CT examinations. A total of 168/266 (63.2%) potentially clinically significant cardiovascular findings were unreported in the original reports of 177/447 (39.6%) subjects (p<0.0001). Senior radiologists tended to more frequently report coronary artery calcification (p=0.0006), cardiac valves calcification (p=0.0003), and ascending aorta enlargement (p=0.01) compared to junior radiologists. Several cardiovascular abnormalities can be reliably identified on standard chest CT. Yet, they are often under-reported, even when they might be relevant to the patient's work-up.

Tracheal tube obstruction in mechanically ventilated patients assessed by high-resolution computed tomography.

Tracheal intubation compromises mucus clearance and secretions accumulate inside the tracheal tube (TT). The aim of this study was to evaluate with a novel methodology TT luminal obstruction in critically ill patients. This was a three-phase study: (1) the authors collected 20 TTs at extubation. High-resolution computed tomography (CT) was performed to determine cross-sectional area (CSA) and mucus distribution within the TT; (2) five TTs partially filled with silicone were used to correlate high-resolution CT results and increased airflow resistance; and (3) 20 chest CT scans of intubated patients were reviewed for detection of secretions in ventilated patients' TT. Postextubation TTs showed a maximum CSA reduction of (mean±SD) 24.9±3.9% (range 3.3 to 71.2%) after a median intubation of 4.5 (interquartile range 2.5 to 6.5) days. CSA progressively decreased from oral to lung end of used TTs. The luminal volume of air was different between used and new TTs for all internal diameters (P<0.01 for new vs. used TTs for all studied internal diameters). The relationship between pressure drop and increasing airflow rates was nonlinear and depended on minimum CSA available to ventilation. Weak correlation was found between TT occlusion and days of intubation (R²=0.352, P=0.006). With standard clinical chest CT scans, 6 of 20 TTs showed measurable secretions with a CSA reduction of 24.0±3.9%. TT luminal narrowing is a common finding and correlates with increased airflow resistance. The authors propose high-resolution CT as a novel technique to visualize and quantify secretions collected within the TT lumen.

Evaluation of automated attenuation-based tube potential selection in combination with organ-specific dose reduction for contrast-enhanced chest CT examinations

To evaluate the influence of attenuation-based tube potential selection (ATPS) in combination with organ-specific dose reduction (OSDR) on radiation dose and image quality of contrast-enhanced chest computed tomography (CT) examinations. Seventy consecutive patients (59.2±16.1 years; 49 men; 21 women) were randomized into two groups and underwent contrast-enhanced chest CT using a 128 section CT scanner. CT examinations were performed as standard protocol in group A (n=35) and with the activated novel dose-saving devices, OSDR and ATPS, in group B (n=35). Objective [signal-to-noise (SNR) and contrast-to-noise ratio (CNR)] and subjective image quality (five-point scale; 1=non diagnostic; 5=excellent) as well as radiation dose (CTDIvol) were analysed. CTDIvol of the protocol using OSDR and ATPS was significantly lower than in standard chest CT examinations (3.4±1 versus 6.1±2.3mGy; p<0.001). Although the level of noise was slightly elevated in group B (14.1±1.7 versus 11.4±1.9HU; p<0.01), no significant differences in SNR (17.1±5 versus 16.3±4.7) or subjective image quality (mean score of 4.6 versus 4.4) were observed between both imaging protocols. Attenuation-based tube potential selection in combination with organ-specific dose reduction essentially reduces the dose of chest CT in patients with normal body mass index (BMI) in clinical routine while maintaining subjective and objective image quality.

Standard chest CT using combined automated tube potential selection and iterative reconstruction: image quality and radiation dose reduction

ObjectiveTo evaluate the image quality and radiation dose reduction of chest computed tomography (CT) using combined automated tube potential selection (ATPS) and iterative reconstruction (IR). Materials and MethodsImage quality and radiation dose were compared between conventional contrast-enhanced chest CT using 120 kVp and filtered back projection (Protocol A) and CT using ATPS and IR (Protocol B) in 43 patients. ResultsThe effective radiation dose was 3.6±0.4 mSv for Protocol A and 2.2±0.6 mSv for Protocol B (mean dose reduction, 39.7%). Protocol B showed diagnostic image quality in all patients. ConclusionATPS and IR allows for radiation dose reduction while maintaining diagnostic image quality.

Comparison of ordinal versus Agatston coronary calcification scoring for cardiovascular disease mortality in community-living individuals

Coronary artery calcification (CAC) by the Agatston method predicts cardiovascular disease (CVD), but requires cardiac gated computed tomography (CT) scans, a procedure not covered by most insurance providers. An ordinal CAC score (scored 0-12 based on artery number and extent of calcification involvement) can be measured on standard chest CTs. However, the correlation of ordinal and Agatston CAC scores and their relative association with CVD mortality is uncertain, which we sought to determine. Nested case-control study. Community-living individuals undergoing "whole body" CT scans for preventive medicine. 4,544 consecutive patients with CT scans, were followed from 2000 to 2009. We selected cases who died of CVD (n=57) and age, sex, and CT slice-thickness matched each case to three controls (N=171). Cardiac gated 3mm chest CTs and non-gated 6mm standard chest CTs. CVD death over 9years follow-up. The intra- and inter-reader kappa for the ordinal CAC score was 0.90 and 0.76 respectively. The correlation of Agatston and ordinal CAC scores was 0.72 (p<0.001). In models adjusted for traditional CVD risk factors, the odds of CVD death per 1 SD greater CAC was 1.66 (1.03-2.68) using the ordinal CAC score and 1.57 (1.00-2.46) using the Agatston score. A simple ordinal CAC score is reproducible, strongly correlated with Agatston CAC scores, and provides similar prediction for CVD death in predominantly Caucasian community-living individuals.

Digital Tomosynthesis of the Chest: Current and Emerging Applications

Digital tomosynthesis (DTS) of the chest is a technique whose basic components are similar to those of digital radiography, but that also provides some of the benefits of computed tomography (CT). The major advantages of DTS over conventional chest radiography are improved visibility of the pulmonary parenchyma and depiction of abnormalities such as pulmonary nodules. Calcifications, vessels, airways, and chest wall abnormalities are also much more readily visualized at DTS than at chest radiography. DTS could potentially be combined with chest radiography to follow up known nodules, confirm or rule out suspected nodules seen at radiography, or evaluate individuals who are at high risk for lung cancer or pulmonary metastases. DTS generates coronal "slices" through the chest whose resolution is superior to that of coronal reconstructed CT images, but it is limited by its suboptimal depth resolution and susceptibility to motion; consequently, potential pitfalls in recognizing lesions adjacent to the pleura, diaphragm, central vessels, and mediastinum can occur. However, the radiation dose and projected cost of chest DTS are lower than those of standard chest CT. Besides pulmonary nodule detection, specific applications of DTS that are under investigation include evaluation of pulmonary tuberculous and nontuberculous mycobacterial disease, cystic fibrosis, interstitial lung disease, and asbestos-related thoracic diseases. A basic understanding of chest DTS and of the emerging applications of this technique can prove useful to the radiologist. Online supplemental material is available for this article.

Thoracic Applications of Dual Energy

Computed tomography (CT) is the core imaging modality for the evaluation of thoracic disorders. With the recently developed dual-energy CT (DECT) technique, the clinical utility of CT in the management of pulmonary diseases can be expanded. The most actively investigated principle of dual energy is material decomposition based on attenuation differences at different energy levels. This technique provides two key insights into lung physiology, that is, regional perfusion and ventilation. This functional information is obtained in addition to morphologic information because high-resolution thoracic anatomy is entirely preserved on dual-energy thoracic CT. The second major possibility offered by DECT is virtual monochromatic imaging that represents a new option for standard chest CT in daily routine. In this review, imaging principles and clinical applications of dual-energy thoracic CT are described. Knowledge of the applications of DECT may lead to wider use of this technique in the field of respiratory disorders.

Möglichkeiten der Dosisreduktion bei CT-Untersuchungen des akuten Thoraxschmerzes

Electrocardiogram-gated (ECG) computed tomography (CT) investigations can be accompanied by high amounts of radiation exposure. This is particularly true for the investigation of patients with unclear and acute chest pain. The common approach in patients with acute chest pain is standard spiral CT of the chest. The chest pain or triple-rule-out CT protocol is a relatively new ECG-gated protocol of the entire chest. This article reviews and discusses different techniques for the CT investigation of patients with acute chest pain. By applying the appropriate scan technique, the radiation exposure for an ECG-gated protocol must not necessarily be higher than a standard chest CT scan Aortic pathologies are far better depicted by ECG-gated scan protocols and depending on the heart rate coronary artery disease can also be detected at the same time. The use of ECG-triggered scans will not support the diagnostics of the pulmonary arteries. However, in unspecific chest pain an ECG-triggered scan protocol can provide information on the differential diagnosis.

Radiation Doses and Risks in Chest Computed Tomography Examinations

Effective doses, and the corresponding risks of radiation-induced cancers, are presented for patients undergoing chest computed tomography (CT) examinations. Patient dose calculations were based on the characteristics of 16-slice CT scanner from 4 imaging equipment vendors. The dose-length product (DLP) was used to quantify the amount of radiation used to perform chest CT examinations. Values of DLP were converted into a corresponding effective dose (E) using age-dependent E/DLP conversion coefficients applicable to chest CT examinations. Calculations of effective doses were performed for a typical chest CT examination, as well as for a low-dose protocol for patients with cystic fibrosis. Effective doses were used to estimate nominal cancer risks based on data in Report VII of the Committee of the Biological Effects of Ionizing Radiation. Patient effective doses in standard chest CT examinations range from approximately 1.7 millisieverts (mSv) in newborns to approximately 5.4 mSv in adults. The effective dose to a 5-year-old patient with cystic fibrosis using a low-dose protocol is approximately 0.55 mSv, which is about a factor of four lower than a standard chest CT examination. An effective dose of 0.55 mSv for a 5-year-old patient corresponds to a nominal excess risk of carcinogenesis of approximately 1.5 cancers per 10,000 individuals, with half of these being fatal. It is concluded that patients undergoing chest CT examinations should have a benefit that exceeds the (small) radiation risk.

Effective Dose Determination Using an Anthropomorphic Phantom and Metal Oxide Semiconductor Field Effect Transistor Technology for Clinical Adult Body Multidetector Array Computed Tomography Protocols

To determine the organ doses and total body effective dose (ED) delivered to an anthropomorphic phantom by multidetector array computed tomography (MDCT) when using standard clinical adult body imaging protocols. Metal oxide semiconductor field effect transistor (MOSFET) technology was applied during the scanning of a female anthropomorphic phantom to determine 20 organ doses delivered during clinical body computed tomography (CT) imaging protocols. A 16-row MDCT scanner (LightSpeed, General Electric Healthcare, Milwaukee, Wis) was used. Effective dose was calculated as the sum of organ doses multiplied by a weighting factor determinant found in the International Commission on Radiological Protection Publication 60. Volume CT dose index and dose length product (DLP) values were recorded at the same time for the same scan. Effective dose (mSv) for body MDCT imaging protocols were as follows: standard chest CT, 6.80 +/- 0.6; pulmonary embolus CT, 13.7 +/- 0.4; gated coronary CT angiography, 20.6 +/- 0.4; standard abdomen and pelvic CT, 13.3 + 1.0; renal stone CT, 4.51 + 0.45. Effective dose calculated by direct organ measurements in the phantom was 14% to 37% greater than those determined by the DLP method. Effective dose calculated by the DLP method underestimates ED as compared with direct organ measurements for the same CT examination. Organ doses and total body ED are higher than previously reported for MDCT clinical body imaging protocols.

Chest computed tomography with multiplanar reformatted images for diagnosing traumatic bronchial rupture: a case report

IntroductionUnnoticed bronchial injury during the early stage of resuscitation of multiple trauma is not rare and increases mortality and morbidity.MethodsThree-dimensional reconstruction of the airways using a workstation connected to a multidetector chest computed tomography (CT) scanner may change the diagnostic strategy in patients with blunt chest trauma with clinical signs evocative of bronchial rupture.ResultsIn this case report of a young motor biker, a complete disruption of the intermediary trunk was first misdiagnosed using standard chest helical CT and bronchoscopy. Postprocessing procedures including three-dimensional extraction of the tracheobronchial tree were determinants for establishing the diagnosis, and emergent surgical repair was successfully performed. Follow-up using CT with three-dimensional reconstructions evidenced a bronchial stenosis located at the site of the rupture.ConclusionThe present study demonstrates the potential interest of performing three-dimensional reconstructions by extraction of the tracheal–bronchial tree in patients with severe blunt chest trauma suspected of bronchial rupture.

Suspected and incidental pulmonary embolism on multidetector-row CT: Analysis of technical and morphological factors influencing the diagnosis in a cross-sectional cancer centre patient cohort

To assess technical and computed tomography (CT) predictors of true-positive (TP) and false-negative (FN) radiological diagnoses in a retrospective patient cohort with pulmonary embolism (PE) in the setting of a cancer centre. Two thousand, four hundred and twelve consecutive chest multidetector-row CT images from 1869 patients were reviewed for presence of PE. CT protocols and TP and FN radiological reports were determined and the clinical files reviewed for suspicion of PE. The severity of PE was assessed by an arterial obstruction index. Ancillary pulmonary findings were scored qualitatively and on a lobar basis. Statistical tests included analysis of variance and univariate and multivariate logistic regressions. Ninety-one out of a total of 111 PE-positive images were included. Thirty-five patients had clinically suspected PE; 56 were not suspected of having PE. Forty-eight patients had TP diagnoses; 43 (39 of whom were not suspected of having PE) had FN radiological diagnoses. FN diagnoses were most frequent in oesophageal (17/19; 89.5%) and standard chest CT (19/35; 54.3%). Pulmonary CT angiography was associated with TP diagnosis (p<0.0001), whereas oesophageal CT was associated with FN diagnosis (p=0.001). Artefacts and arterial attenuation did not influence PE detection (p=0.017 and 0.066 for artefacts and arterial attenuation, respectively). However, the arterial obstruction index strongly predicted PE diagnosis (p=0.001). This was confirmed on multivariate analysis (p=0.041, 0.027 and 0.020 for pulmonary CT angiography, oesophageal protocols and arterial obstruction index, respectively). When stratified for clinically unsuspected cases, the arterial obstruction index remained the only predictor of PE diagnosis (p=0.009). Predictors of PE diagnosis were PE severity and technical factors; the latter were linked to clinical suspicion of PE. Arterial enhancement appears unlikely to contribute to missed diagnoses, if judged adequate for diagnosis of PE, and ancillary chest findings are unlikely to improve embolus detection.