Next-generation sequencing using tissue specimen collected with a 1.1 mm-diameter cryoprobe in patients with lung cancer.

BACKGROUND AND OBJECTIVE: Next-generation sequencing (NGS) analysis is considered standard for lung cancer diagnosis in clinical practice. Little is known about the feasibility of NGS using tumour tissue sampled with a 1.1 mm-diameter cryoprobe. We aimed to investigate the suitability of specimens obtained by transbronchial cryobiopsy (TBC) using a 1.1 mm-diameter cryoprobe for NGS analysis. METHODS: Patients with lung cancer who underwent TBC using a 1.1 mm-diameter cryoprobe for NGS testing between October 2020 and April 2023 were enrolled. A 4.0- or 3.0 mm-diameter bronchoscope with radial probe endobronchial ultrasound and virtual bronchoscopic navigation was used to detect peripheral lung lesions. All procedures were performed under fluoroscopic guidance. Data were analysed retrospectively. RESULTS: A total of 56 patients underwent TBC using a 1.1 mm cryoprobe for NGS testing, during the study period. Most patients (98%) were in the advanced stage of lung cancer (recurrent or inoperable disease of stages III or IV). The diagnostic yield of NGS for DNA and RNA sequencing was 95% each (53 of 56). Moderate bleeding was noted in three patients (5%) and none of the study patients developed life-threatening complications, such as pneumothorax or lung infection. CONCLUSION: TBC using a 1.1 mm-diameter cryoprobe is a useful and safe tool for NGS analysis, for both DNA and RNA sequencing.

Non-ECG-gated high-pitch CT angiography versus hybrid ECG-gated CT angiography for aorta using 512-slice CT: comparison of image quality and radiation dose.

BACKGROUND: There have been few reports comparing image quality and radiation dose of aorta computed tomography angiography (CTA) between the high-pitch and the hybrid technique. PURPOSE: To compare the image quality and radiation dose among non-electrocardiogram (ECG)-gated high-pitch CTA and hybrid ECG-gated CTA of the aorta using 512-slice CT. MATERIAL AND METHODS: This retrospective study included 110 patients who underwent non-ECG-gated high-pitch CTA (group 1) or hybrid ECG-gated CTA (group 2) of the entire aorta. Interpretability, image noise, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and the mean effective radiation dose were compared. RESULTS: The mean image noise of the whole aorta was significantly lower (15.7 ± 1.8 HU vs. 16.5 ± 1.2 HU, P = 0.008) in group 1 than in group 2. The CNR (22.3 ± 4.7 vs. 20.0 ± 3.9, P < 0.001) and SNR (26.5 ± 4.9 vs. 23.2 ± 4.0, P < 0.001) were higher in group 2 compared with group 1. Neither group showed a significant difference in interpretability of the ascending aorta, cardiac chamber, aortic valve, right ostium, and left ostium (all P = 1). The mean effective radiation dose was significantly lower in group 1 than in group 2 (3.5 ± 0.9 mSv vs. 4.3 ± 0.8 mSv, P < 0.001). CONCLUSION: The non-ECG-gated high-pitch technique shows significantly improved CNR and SNR due to reduced noise with lower radiation exposure. The interpretability of the cardiac structure, ascending aorta, aortic valve, and both ostia did not differ significantly between the two groups.

Incremental benefits of size-zone matrix-based radiomics features for the prognosis of lung adenocarcinoma: advantage of spatial partitioning on tumor evaluation.

OBJECTIVES: Prognostic models of lung adenocarcinoma (ADC) can be built using radiomics features from various categories. The size-zone matrix (SZM) features have a strong biological basis related to tumor partitioning, but their incremental benefits have not been fully explored. In our study, we aimed to evaluate the incremental benefits of SZM features for the prognosis of lung ADC. METHODS: A total of 298 patients were included and their pretreatment computed tomography images were analyzed in fivefold cross-validation. We built a risk model of overall survival using SZM features and compared it with a conventional radiomics risk model and a clinical variable-based risk model. We also compared it with other models incorporating various combinations of SZM features, other radiomics features, and clinical variables. A total of seven risk models were compared and evaluated using the hazard ratio (HR) on the left-out test fold. RESULTS: As a baseline, the clinical variable risk model showed an HR of 2.739. Combining the radiomics signature with SZM feature was better (HR 4.034) than using radiomics signature alone (HR 3.439). Combining radiomics signature, SZM feature, and clinical variable (HR 6.524) fared better than just combining radiomics signature and clinical variables (HR 4.202). These results confirmed the added benefits of SZM features for prognosis in lung ADC. CONCLUSION: Combining SZM feature with the radiomics signature was better than using the radiomics signature alone and the benefits of SZM features were maintained when clinical variables were added confirming the incremental benefits of SZM features for lung ADC prognosis. KEY POINTS: • Size-zone matrix (SZM) features provide incremental benefits for the prognosis of lung adenocarcinoma. • Combining the radiomics signature with SZM features performed better than using a radiomics signature alone.

Safety and Diagnostic Yield of Radial Probe Endobronchial Ultrasound-Guided Biopsy for Peripheral Lung Lesions in Patients with Idiopathic Pulmonary Fibrosis: A Multicenter Cross-Sectional Study.

BACKGROUND: Radial probe endobronchial ultrasound-guided transbronchial lung biopsy (RP-EBUS-TBLB) is widely used for diagnosis of peripheral lung lesions (PLLs). To date, there have been no reports regarding the clinical outcomes of RP-EBUS-TBLB for PLLs in patients with idiopathic pulmonary fibrosis (IPF). OBJECTIVES: This study was performed between October 2017 and December 2019 to identify the safety and diagnostic performance of RP-EBUS-TBLB in IPF patients. METHODS: Patients were divided into the usual interstitial pneumonia (UIP) group (n = 39, 4%), the probable UIP group (n = 12, 1%), and the noninterstitial lung disease (non-ILD) group (n = 903, 95%). RESULTS: The diagnostic yield was significantly lower in the UIP group than in the non-ILD group (62% vs. 76%; p = 0.042), but there were no significant differences between the UIP and probable UIP groups (62% vs. 83%; p = 0.293) or the probable UIP and non-ILD groups (83% vs. 76%; p = 0.741). Multivariate logistic analysis showed that the mean diameter of PLLs, positive bronchus sign on CT, and "within the lesion" status on EBUS were independently associated with success of the procedure. Especially, the presence of the UIP pattern on CT (OR, 0.385; 95% CI: 0.172-0.863; p = 0.020) was independently associated with failed diagnosis. Among patients with UIP, "within the lesion" status on EBUS (OR, 25.432; 95% CI: 2.321-278.666; p = 0.008) was shown to be a factor contributing to a successful diagnosis. Overall, there were no significant differences in complication rates among the 3 study groups. CONCLUSION: RP-EBUS-TBLB can be performed safely with an acceptable diagnostic yield, even in patients with IPF.

Role of digital tomosynthesis in the context of tuberculosis contact investigation: comparisons with digital radiography.

BACKGROUND: Chest radiography value as a screening tool in those exposed to pulmonary tuberculosis (TB) is reduced by its lower sensitivity to detect small intrapulmonary lesions. PURPOSE: To evaluate the efficacy of digital tomosynthesis (DTS) screening of individuals that had contacted persons with active TB using low-dose computed tomography (CT) as the reference standard methods. MATERIAL AND METHODS: This retrospective, community-based screening study of 90 adults who had been in close contact with a TB case was undertaken at our institution. All individuals underwent clinical evaluation, digital radiography (DR), DTS, and low-dose chest CT. Observers assessed and classified DR and DTS images using CT as the reference-standard method. Based on clinical and imaging findings, TB status was classified as normal, latent, minimal, subclinical, and active. Diagnostic performances of DTS and DR for the interpretation of correct diagnosis were calculated. RESULTS: The estimated effective doses for DR, DTS, and low-dose CT were 0.01 mSv, 0.1 mSv, and 0.33 mSv, respectively. TB statuses of the 90 individuals were as follows: 62 latent (68.9%); two subclinical (2.2%); and one minimal (1.1%). The sensitivities, specificities, and accuracies of DTS and DR in the interpretation of correct diagnosis were 75.8%, 100%, 91.1% and 48.5%, 96.5%, 78.9%, respectively. CONCLUSION: DTS appears to be superior to DR for the detection of lung lesions in individuals with TB contacts. DTS can offer a reasonable option for TB contact investigation.

Usefulness of Contrast-Enhanced CT in a Patient with Acute Phlegmonous Esophagitis: A Case Report and Literature Review.

Acute phlegmonous esophagitis is a very rare, life-threatening form of esophagitis, characterized by diffuse bacterial infection and pus formation within the submucosal and muscularis layers of the esophagus. We describe a case in which contrast-enhanced chest CT was useful for evaluating the severity of phlegmonous esophagitis, which was overlooked and underestimated by endoscopy.

Marginal radiomics features as imaging biomarkers for pathological invasion in lung adenocarcinoma.

OBJECTIVES: Lung adenocarcinomas which manifest as ground-glass nodules (GGNs) have different degrees of pathological invasion and differentiating among them is critical for treatment. Our goal was to evaluate the addition of marginal features to a baseline radiomics model on computed tomography (CT) images to predict the degree of pathologic invasiveness. METHODS: We identified 236 patients from two cohorts (training, n = 189; validation, n = 47) who underwent surgery for GGNs. All GGNs were pathologically confirmed as adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), or invasive adenocarcinoma (IA). The regions of interest were semi-automatically annotated and 40 radiomics features were computed. We selected features using L1-norm regularization to build the baseline radiomics model. Additional marginal features were developed using the cumulative distribution function (CDF) of intratumoral intensities. An improved model was built combining the baseline model with CDF features. Three classifiers were tested for both models. RESULTS: The baseline radiomics model included five features and resulted in an average area under the curve (AUC) of 0.8419 (training) and 0.9142 (validation) for the three classifiers. The second model, with the additional marginal features, resulted in AUCs of 0.8560 (training) and 0.9581 (validation). All three classifiers performed better with the added features. The support vector machine showed the most performance improvement (AUC improvement = 0.0790) and the best performance was achieved by the logistic classifier (validation AUC = 0.9825). CONCLUSION: Our novel marginal features, when combined with a baseline radiomics model, can help differentiate IA from AIS and MIA on preoperative CT scans. KEY POINTS: • Our novel marginal features could improve the existing radiomics model to predict the degree of pathologic invasiveness in lung adenocarcinoma.

Feasibility of Ultra-Low-Dose CT for Bronchoscopy of Peripheral Lung Lesions.

Background and objectives: Thin-section computed tomography (CT) is essential for identifying small bronchi during bronchoscopy using radial endobronchial ultrasound. Some patients should receive an additional CT for a thin-section image. We performed a retrospective study with a prospectively collected database to identify the optimal radiation dose for thin-section CT during peripheral bronchoscopy. Materials and Methods: In total, 91 patients with peripheral lung lesions underwent thin-section CT (both standard CT as a reference and ultra-low-dose CT (ultra-LDCT)). The patients were randomly assigned to one of four groups according to the ultra-LDCT parameters: group 1 = 120 kVp, 25 mAs; group 2 = 100 kVp, 15 mAs; group 3 = 120 kVp, 5 mAs; and group 4 = 100 kVp, 5 mAs. Two radiologists and two physicians analyzed both the standard CT and ultra-LDCT. Results: The effective doses (EDs) of ultra-LDCT significantly differed among the four groups (median EDs were 0.88, 0.34, 0.19, and 0.12 mSv for groups 1-4, respectively; p < 0.001). Median differences in peripheral airway wall thickness were higher in group 4 than in other groups (differences in median wall thickness measured by two radiologists were 0.4-0.5 mm and 0.8-0.9 mm for groups 1-3 and group 4, respectively). Bronchus signs on ultra-LDCT in groups 1 and 2 were well correlated with those of the standard-dose CT (accuracies of two radiologists and two pulmonary physicians were 95-100%). Conclusions: Our results indicate that ultra-LDCT with ED of >0.34 mSv (ED of group 2) is feasible for peripheral bronchoscopy.

Feasibility of low dose chest CT for virtual bronchoscopy navigation in a porcine model.

BACKGROUND: Virtual bronchoscopy navigation (VBN) is widely used for assistance in the histological examination of lung nodules. However, little is known about the optimal CT radiation dose for VBN. Therefore, we performed an animal study to evaluate the feasibility of low dose CT (LDCT) for VBN. METHODS: Ten pigs underwent standard dose CT (as a reference) and four different LDCT protocols: LDCT 1, 120 kVp, 15 mAs; LDCT 2, 120 kVp, 8 mAs; LDCT 3, 100 kVp, 7 mAs; and LDCT 4, 100 kVp, 4 mAs. As targets for the VBN, 10 mm virtual lesions were created in the central and peripheral bronchi. To assess the performance of the VBN, the navigation direction (direction of reconstructed pathways to the target) and the number of branching's (the number of peripheral bronchi to the target) were evaluated. RESULTS: The mean effective doses significantly differed across the four LDCTs (P <  0.001). For both central and peripheral virtual targets, there were significant differences in the accuracy of the navigation direction and the number of branching's of the VBNs across the four LDCTs (P <  0.001 for all). Regarding the accuracy of the navigation direction and the number of branching's, the areas under the curves of the ROCs were 0.9352 and 0.9324, respectively, for central virtual targets, and 0.8696 and 0.8783, respectively, for peripheral virtual targets. Youden's index indicated that the optimal effective CT scan dose for both central and peripheral virtual targets was 0.238 mSv. CONCLUSIONS: LDCT is feasible for VBN.

Clinical outcomes of radial probe endobronchial ultrasound using a guide sheath for diagnosis of peripheral lung lesions in patients with pulmonary emphysema.

BACKGROUND: Generally, structural destruction of lung parenchyma, such as pulmonary emphysema, is considered to be related to the low diagnostic yields and high complication rates of lung biopsies of peripheral lung lesions. Currently, little is known about the clinical outcomes of using endobronchial ultrasound with a guide sheath (EBUS-GS) to diagnose peripheral lesions in patients with emphysema. METHODS: This retrospective study was performed to identify the clinical outcomes of EBUS-GS in patients with pulmonary emphysema. This study included 393 consecutive patients who received EBUS-GS between February 2017 and April 2018. The patients were classified according to the severity of their emphysema, and factors possibly contributing to a successful EBUS-GS procedure were evaluated. RESULTS: The overall diagnostic yield of EBUS-GS in patients with no or mild emphysema was significantly higher than in those with moderate or severe pulmonary emphysema (78% vs. 61%, P = 0.007). There were no procedure-related complications. The presence of a bronchus sign on CT (P <  0.001) and a "within the lesion" status on EBUS (P = 0.009) were independently associated with a successful EBUS-GS procedure. Although the diagnostic yield of EBUS-GS in patients with moderate-to-severe emphysema was relatively low, a bronchus sign and "within the lesion" status on EBUS were contributing factors for a successful EBUS-GS. CONCLUSIONS: EBUS-GS is a safe procedure with an acceptable diagnostic yield, even when performed in patients with pulmonary emphysema. The presence of a bronchus sign and "within the lesion" status on EBUS were predictors of a successful procedure.

Risk stratification of ductal carcinoma in situ using whole-lesion histogram analysis of the apparent diffusion coefficient.

OBJECTIVES: To investigate the value of the whole-lesion histogram apparent diffusion coefficient (ADC) metrics for differentiating low-risk from non-low-risk ductal carcinoma in situ (DCIS). METHODS: The authors identified 93 women with pure DCIS who had undergone preoperative MR imaging and diffusion-weighted imaging from 2013 to 2016. Histogram analysis of pixel-based ADC data of the whole tumour volume was performed by two radiologists using a software tool. The results were compared between low-risk and non-low-risk DCIS. Associations between quantitative ADC metrics and low-risk DCIS were evaluated by receiver operating characteristics (ROC) curve and logistic regression analyses. RESULTS: In whole-lesion histogram analysis, mean ADC and 5th, 50th and 95th percentiles of ADC were significantly different between low-risk and non-low-risk DCIS (1.522, 1.207, 1.536 and 1.854 × 10-3 mm2/s versus 1.270, 0.917, 1.261 and 1.657 × 10-3 mm2/s, respectively; p = .004, p = .003, p = .004 and p = .024, respectively). ROC curve analysis for differentiating low-risk DCIS revealed that 5th percentile ADC yielded the largest area under the curve (0.786) among the metrics of whole-lesion histogram, and the optimal cut-off point was 1.078 × 10-3 mm2/s (sensitivity 80%, specificity 75.9%, p = .001). Multivariate regression analysis revealed that a high 5th percentile of ADC (> 1.078× 10-3 mm2/s; odds ratio [OR] = 10.494, p = .016), small tumour size (≤ 2 cm; OR = 12.692, p = .008) and low Ki-67 status (< 14%; OR = 10.879, p = .046) were significantly associated with low-risk DCIS. CONCLUSIONS: Assessment with whole-lesion histogram analysis of the ADC could be helpful for identifying patients with low-risk DCIS. KEY POINTS: • Whole-lesion histogram ADC metrics could be helpful for differentiating low-risk from non-low-risk DCIS. • A high 5th percentile ADC was a significant factor associated with low-risk DCIS. • Risk stratification of DCIS is important for their management.

Bronchoscopic management of solitary bronchial myelolipoma: a case report.

BACKGROUND: Myelolipoma is a rare benign tumor composed of mature adipose and hematopoietic tissues. Most myelolipomas are found in the adrenal glands, whereas intrathoracic myelolipoma is extremely rare. In particular, bronchial myelolipoma without the involvement of lung parenchyma has never been reported. CASE PRESENTATION: A previously healthy 38-year-old male developed dyspnea and a productive cough. Computed tomography revealed an endobronchial mass at the right bronchus intermedius and subsequent atelectasis of the right middle and lower lobes. Flexible bronchoscopy found a total obstruction of the right bronchus intermedius due to an endobronchial tumor. Using a rigid bronchoscope, the endobronchial tumor was resected and the base of the tumor was additionally ablated with a diode laser to prevent recurrence. The removed endobronchial tumor was a 13 mm × 20 mm-sized oval-shaped mass and was pathologically diagnosed as bronchial myelolipoma. Chest radiographs, obtained on the day following the procedure, showed an improvement of atelectasis, and accompanying symptoms were immediately improved. Follow-up bronchoscopy performed after 12 months evidenced no recurrence of the bronchial myelolipoma. CONCLUSIONS: We used bronchoscopic intervention in patients with solitary bronchial myelolipoma and there was no evidence of recurrence.

Comprehensive Computed Tomography Radiomics Analysis of Lung Adenocarcinoma for Prognostication.

BACKGROUND: In this era of personalized medicine, there is an expanded demand for advanced imaging biomarkers that reflect the biology of the whole tumor. Therefore, we investigated a large number of computed tomography-derived radiomics features along with demographics and pathology-related variables in patients with lung adenocarcinoma, correlating them with overall survival. MATERIALS AND METHODS: Three hundred thirty-nine patients who underwent operation for lung adenocarcinoma were included. Analysis was performed using 161 radiomics features, demographic, and pathologic variables and correlated each with patient survival. Prognostic performance for survival was compared among three models: (a) using only clinicopathological data; (b) using only selected radiomics features; and (c) using both clinicopathological data and selected radiomics features. RESULTS: At multivariate analysis, age, pN, tumor size, type of operation, histologic grade, maximum value of the outer 1/3 of the tumor, and size zone variance were statistically significant variables. In particular, maximum value of outer 1/3 of the tumor reflected tumor microenvironment, and size zone variance represented intratumor heterogeneity. Integration of 31 selected radiomics features with clinicopathological variables led to better discrimination performance. CONCLUSION: Radiomics approach in lung adenocarcinoma enables utilization of the full potential of medical imaging and has potential to improve prognosis assessment in clinical oncology. IMPLICATIONS FOR PRACTICE: Two radiomics features were prognostic for lung cancer survival at multivariate analysis: (a) maximum value of the outer one third of the tumor reflects the tumor microenvironment and (b) size zone variance represents the intratumor heterogeneity. Therefore, a radiomics approach in lung adenocarcinoma enables utilization of the full potential of medical imaging and could play a larger role in clinical oncology.

Pleurodesis Using Mistletoe Extract Delivered via a Spray Catheter during Semirigid Pleuroscopy for Managing Symptomatic Malignant Pleural Effusion.

BACKGROUND: Talc poudrage during thoracoscopy is considered the standard procedure for patients with symptomatic malignant pleural effusion (MPE). Until now, no alternative technique other than talc poudrage for pleurodesis during medical thoracoscopy has been proposed. Liquid sclerosants, such as mistletoe extract, have been sprayed evenly into the pleural cavity during semirigid pleuroscopy for chemical pleurodesis. OBJECTIVE: We conducted a retrospective study using the database of semirigid pleuroscopy to identify the usefulness of pleurodesis using a mistletoe extract delivered via a spray catheter during semirigid pleuroscopy for symptomatic MPE. METHODS: All consecutive patients with symptomatic MPE who underwent semirigid pleuroscopy from October 2015 to September 2016 were registered. The responses were evaluated using chest X- ray or computed tomography 4 weeks after pleurodesis. RESULTS: The study included 43 patients who underwent pleurodesis with mistletoe extract via a spray catheter during semirigid pleuroscopy. Complete and partial responses were seen in 21 (49%) and 19 (44%) patients, respectively. The median duration of chest tube placement after pleurod-esis was 7 days (range 6-8 days) in the 40 patients with complete or partial responses. No cases of severe hemorrhage, empyema formation, respiratory failure, or procedure-related mortality were observed in the subjects at 4 weeks after semirigid pleuroscopy. CONCLUSION: Pleurodesis with mistletoe extract delivered via a spray catheter during semirigid pleuroscopy is a safe and effective procedure for managing symptomatic MPE.

Radial probe endobronchial ultrasound using a guide sheath for peripheral lung lesions in beginners.

BACKGROUND: The diagnostic yields and safety profiles of transbronchial lung biopsy have not been evaluated in inexperienced physicians using the combined modality of radial probe endobronchial ultrasound and a guide sheath (EBUS-GS). This study assessed the utility and safety of EBUS-GS during the learning phase by referring to a database of performed EBUS-GS procedures. METHODS: From December 2015 to January 2017, all of the consecutive patients who underwent EBUS-GS were registered. During the study period, two physicians with no previous experience performed the procedure. To assess the diagnostic yields, learning curve, and safety profile of EBUS-GS performed by these inexperienced physicians, the first 100 consecutive EBUS-GS procedures were included in the evaluation. RESULTS: The overall diagnostic yield of EBUS-GS performed by two physicans in 200 patients with a peripheral lung lesion was 73.0%. Learning curve analyses showed that the diagnostic yields were stable, even when the procedure was performed by beginners. Complications related to EBUS-GS occurred in three patients (1.5%): pneumothorax developed in two patients (1%) and resolved spontaneously without chest tube drainage; another patient (0.5%) developed a pulmonary infection after EBUS-GS. There were no cases of pneumothorax requiring chest tube drainage, severe hemorrhage, respiratory failure, premature termination of the procedure, or procedure-related mortality. CONCLUSIONS: EBUS-GS is a safe and stable procedure with an acceptable diagnostic yield, even when performed by physicians with no previous experience.

Hybrid ECG-gated versus non-gated 512-slice CT angiography of the aorta and coronary artery: image quality and effect of a motion correction algorithm.

Background Using the hybrid electrocardiogram (ECG)-gated computed tomography (CT) technique, assessment of entire aorta, coronary arteries, and aortic valve can be possible using single-bolus contrast administration within a single acquisition. Purpose To compare the image quality of hybrid ECG-gated and non-gated CT angiography of the aorta and evaluate the effect of a motion correction algorithm (MCA) on coronary artery image quality in a hybrid ECG-gated aorta CT group. Material and Methods In total, 104 patients (76 men; mean age = 65.8 years) prospectively randomized into two groups (Group 1 = hybrid ECG-gated CT; Group 2 = non-gated CT) underwent wide-detector array aorta CT. Image quality, assessed using a four-point scale, was compared between the groups. Coronary artery image quality was compared between the conventional reconstruction and motion correction reconstruction subgroups in Group 1. Results Group 1 showed significant advantages over Group 2 in aortic wall, cardiac chamber, aortic valve, coronary ostia, and main coronary arteries image quality (all P < 0.001). All Group 1 patients had diagnostic image quality of the aortic wall and left ostium. The MCA significantly improved the image quality of the three main coronary arteries ( P < 0.05). Moreover, per-vessel interpretability improved from 92.3% to 97.1% with the MCA ( P = 0.013). Conclusion Hybrid ECG-gated CT significantly improved the heart and aortic wall image quality and the MCA can further improve the image quality and interpretability of coronary arteries.

Ultra-low-dose lung screening CT with model-based iterative reconstruction: an assessment of image quality and lesion conspicuity.

Background Reducing radiation dose inevitably increases image noise, and thus, it is important in low-dose computed tomography (CT) to maintain image quality and lesion detection performance. Purpose To assess image quality and lesion conspicuity of ultra-low-dose CT with model-based iterative reconstruction (MBIR) and to determine a suitable protocol for lung screening CT. Material and Methods A total of 120 heavy smokers underwent lung screening CT and were randomly and equally assigned to one of five groups: group 1 = 120 kVp, 25 mAs, with FBP reconstruction; group 2 = 120 kVp, 10 mAs, with MBIR; group 3 = 100 kVp, 15 mAs, with MBIR; group 4 = 100 kVp, 10 mAs, with MBIR; and group 5 = 100 kVp, 5 mAs, with MBIR. Two radiologists evaluated intergroup differences with respect to radiation dose, image noise, image quality, and lesion conspicuity using the Kruskal-Wallis test and the Chi-square test. Results Effective doses were 61-87% lower in groups 2-5 than in group 1. Image noises in groups 1 and 5 were significantly higher than in the other groups ( P < 0.001). Overall image quality was best in group 1, but diagnostic acceptability of overall image qualities in groups 1-3 was not significantly different (all P values > 0.05). Lesion conspicuities were similar in groups 1-4, but were significantly poorer in group 5. Conclusion Lung screening CT with MBIR obtained at 100 kVp and 15 mAs enables a ∼60% reduction in radiation dose versus low-dose CT, while maintaining image quality and lesion conspicuity.

Serial changes and prognostic implications of CT findings in combined pulmonary fibrosis and emphysema: comparison with fibrotic idiopathic interstitial pneumonias alone.

Background Although fibrotic idiopathic interstitial pneumonias (IIPs) alone and those combined with pulmonary emphysema are naturally progressive diseases, the process of deterioration and outcomes are variable. Purpose To evaluate and compare serial changes of computed tomography (CT) abnormalities and prognostic predictive factors in fibrotic IIPs alone and those combined with pulmonary emphysema. Material and Methods A total of 148 patients with fibrotic IIPs alone (82 patients) and those combined with pulmonary emphysema (66 patients) were enrolled. Semi-quantitative CT analysis was used to assess the extents of CT characteristics which were evaluated on initial and follow-up CT images. Univariate and multivariate analyses were performed to assess the effects of clinical and CT variables on survival. Results Significant differences were noted between fibrotic scores, as determined using initial CT scans, in the fibrotic IIPs alone (21.22 ± 9.83) and those combined with pulmonary emphysema groups (14.70 ± 7.28) ( P < 0.001). At follow-up CT scans, changes in the extent of ground glass opacities (GGO) were greater ( P = 0.031) and lung cancer was more prevalent ( P = 0.001) in the fibrotic IIPs combined with pulmonary emphysema group. Multivariate Cox proportional hazards analysis showed changes in the extent of GGO (hazard ratio, 1.056) and the presence of lung cancer (hazard ratio, 4.631) were predictive factors of poor survivals. Conclusion Although patients with fibrotic IIPs alone and those combined with pulmonary emphysema have similar mortalities, lung cancer was more prevalent in patients with fibrotic IIPs combined with pulmonary emphysema. Furthermore, changes in the extent of GGO and the presence of lung cancer were independent prognostic factors of poor survivals.

Prognostic impact of nomogram based on whole tumour size, tumour disappearance ratio on CT and SUVmax on PET in lung adenocarcinoma.

OBJECTIVES: Lung adenocarcinoma frequently manifests as subsolid nodules, and the solid portion and ground-glass-opacity (GGO) portion on CT have different prognostic significance. Therefore, current T descriptor, defined as the whole tumour diameter without discrimination between solid and GGO, is insufficient. We aimed to determine the prognostic significance of solid tumour size and attempt to include prognostic factors such as tumour disappearance rate (TDR) on CT and SUVmax on PET/CT. METHODS: Five hundred and ninety-five patients with completely resected lung adenocarcinoma were analyzed. We developed a nomogram using whole tumour size, TDR, and SUVmax. External validation was performed in another 102 patients. RESULTS: In patients with tumours measuring ≤2 cm and >2 to 3 cm, disease free survival (DFS) was significantly associated with solid tumour size (P < 0.001), but not with whole tumour size (P = 0.052). Developed nomogram was significantly superior to the conventional T stage (area under the curve of survival ROC; P = 0.013 by net reclassification improvement) in stratification of patient survival. In the external validation group, significant difference was noted in DFS according to proposed T stage (P = 0.009). CONCLUSIONS: Nomogram-based T descriptors provide better prediction of survival and assessment of individual risks than conventional T descriptors. KEY POINTS: • Current measurement of whole tumour diameter including ground-glass opacity is insufficient • TDR enables differentiation between invasive solid portion and non-invasive GGO portion • SUVmax demonstrates the biological aggressiveness of the tumour • We developed a nomogram using whole tumour size, TDR, and SUVmax • Nomogram-based clinical T descriptors provide better prediction of survival.

Effectiveness of Adaptive Statistical Iterative Reconstruction for 64-Slice Dual-Energy Computed Tomography Pulmonary Angiography in Patients With a Reduced Iodine Load: Comparison With Standard Computed Tomography Pulmonary Angiography.

OBJECTIVE: The aim of the study was to assess the effectiveness of the adaptive statistical iterative reconstruction (ASIR) for dual-energy computed tomography pulmonary angiography (DE-CTPA) with a reduced iodine load. MATERIALS AND METHODS: One hundred forty patients referred for chest CT were randomly divided into a DE-CTPA group with a reduced iodine load or a standard CTPA group. Quantitative and qualitative image qualities of virtual monochromatic spectral (VMS) images with filtered back projection (VMS-FBP) and those with 50% ASIR (VMS-ASIR) in the DE-CTPA group were compared. Image qualities of VMS-ASIR images in the DE-CTPA group and ASIR images in the standard CTPA group were also compared. RESULTS: All quantitative and qualitative indices, except attenuation value of pulmonary artery in the VMS-ASIR subgroup, were superior to those in the VMS-FBP subgroup (all P < 0.001). Noise and signal-to-noise ratio of VMS-ASIR images were superior to those of ASIR images in the standard CTPA group (P < 0.001 and P = 0.007, respectively). Regarding qualitative indices, noise was significantly lower in VMS-ASIR images of the DE-CTPA group than in ASIR images of the standard CTPA group (P = 0.001). CONCLUSIONS: The ASIR technique tends to improve the image quality of VMS imaging. Dual-energy computed tomography pulmonary angiography with ASIR can reduce contrast medium volume and produce images of comparable quality with those of standard CTPA.