Ultra-high resolution computed tomography with deep-learning-reconstruction: diagnostic ability in the assessment of gastric cancer and the depth of invasion.

PURPOSE: To evaluate the image quality of ultra-high-resolution CT (U-HRCT) images reconstructed using an improved deep-learning-reconstruction (DLR) method. Additionally, we assessed the utility of U-HRCT in visualizing gastric wall structure, detecting gastric cancer, and determining the depth of invasion. METHODS: Forty-six patients with resected gastric cancer who underwent preoperative contrast-enhanced U-HRCT were included. The image quality of U-HRCT reconstructed using three different methods (standard DLR [AiCE], improved DLR-AiCE-Body Sharp [improved AiCE-BS], and hybrid-IR [AIDR3D]) was compared. Visualization of the gastric wall's three-layered structure in four regions and the visibility of gastric cancers were compared between U-HRCT and conventional HRCT (C-HRCT). The diagnostic ability of U-HRCT with the improved AiCE-BS for determining the depth of invasion of gastric cancers was assessed using postoperative pathology specimens. RESULTS: The mean noise level of U-HRCT with the improved AiCE-BS was significantly lower than that of the other two methods (p < 0.001). The overall image quality scores of the improved AiCE-BS images were significantly higher (p < 0.001). U-HRCT demonstrated significantly better conspicuity scores for the three-layered structure of the gastric wall than C-HRCT in all regions (p < 0.001). In addition, U-HRCT was found to have superior visibility of gastric cancer in comparison to C-HRCT (p < 0.001). The correct diagnostic rates for determining the depth of invasion of gastric cancer using C-HRCT and U-HRCT were 80%. CONCLUSIONS: U-HRCT reconstructed with the improved AiCE-BS provides clearer visualization of the three-layered gastric wall structure than other reconstruction methods. It is also valuable for detecting gastric cancer and assessing the depth of invasion.

Volume changes of diseased and normal areas in progressive fibrosing interstitial lung disease on inspiratory and expiratory computed tomography.

PURPOSE: The diagnosis of progressive fibrosing interstitial lung disease (PF-ILD) using computed tomography (CT) is an important medical practice in respiratory care, and most imaging findings for this disease have been obtained with inspiratory CT. It is possible that some characteristic changes in respiration may be seen in normal and diseased lung in PF-ILD, which may lead to a new understanding of the pathogenesis of interstitial pneumonia, but it has never been examined. In this study, we collected and selected inspiratory and expiratory CT scans performed in pure PF-ILD cases, and evaluated the volumes of diseased and normal lung separately by manual detection and 3-dimensional volumetry to characterize the dynamic features of PF-ILD. MATERIALS AND METHODS: Cases were collected retrospectively from a total of 753 inspiratory and expiratory CT scans performed at our hospital over a 3-year period. Sixteen cases of pure PF-ILD, excluding almost all other diseases, were included. We measured their diseased, normal, and the whole lung volumes manually and evaluated the correlation of their values and their relationship with respiratory function tests (FVC, FVC%-predicted, and DLCO%-predicted). RESULTS: The relative expansion rate of the diseased lung is no less than that of the normal lung. The "Expansion volume of total lung" divided by the "Expansion volume of normal lung" was found to be significantly associated with DLCO%-predicted abnormalities (p = 0.0073). CONCLUSION: The diseased lung in PF-ILD retained expansion capacity comparable to the normal lung, suggesting a negative impact on respiratory function.

Breath-hold High-resolution T1-weighted Gradient Echo Liver MR Imaging with Compressed Sensing Obtained during the Gadoxetic Acid-enhanced Hepatobiliary Phase: Image Quality and Lesion Visibility Compared with a Standard T1-weighted Sequence.

PURPOSE: To evaluate the feasibility of breath-hold (BH) high-resolution (HR) T1-weighted gradient echo hepatobiliary phase (HBP) imaging using compressed sensing (CS) in gadoxetic acid-enhanced liver MRI in comparison with standard HBP imaging using parallel imaging (PI). METHODS: The study included 122 patients with liver tumors with hypointensity in the HBP who underwent both HR HBP imaging with CS and standard HBP imaging with PI. Two radiologists evaluated the liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, image noise, and overall image quality, as well as the lesion conspicuity on HR and standard HBP imaging and the contrast-enhanced (CE) MR cholangiography (MRC) image quality reconstructed from HBP images. As a quantitative analysis, the SNR of the liver and the liver to lesion signal intensity ratio (LLSIR) were also determined. RESULTS: The liver edge sharpness, hepatic vessel conspicuity, bile duct conspicuity, and overall image quality as well as the lesion conspicuity and the LLSIR on HR HBP imaging with CS were significantly higher than those on standard HBP imaging (all of P < 0.001). The image quality of CE-MRC reconstructed from HR HBP imaging with CS was also significantly higher than that from standard HBP imaging (P < 0.001). Conversely, the SNR of liver in standard HBP was significantly higher than that in HR HBP with CS (P < 0.001). CONCLUSION: BH HR HBP imaging with CS provided an improved overall image quality, lesion conspicuity, and CE-MRC visualization when compared with standard HBP imaging without extending the acquisition time.

Longitudinal changes in renal volumes evaluated by automated three-dimensional volumetric computed tomography of the whole kidney: The association with the renal function and disease progression.

PURPOSE: To clarify the changes in the total renal volume over time with changes of the renal function using automated 3D volumetric CT of the whole kidney and to evaluate the usefulness of the total renal volume CT measurement in predicting chronic kidney disease (CKD) grade progression. METHODS: A total of 961 patients who underwent abdominal CT at least twice (an interval of more than 4 years) were included. The automated 3D volumetric CT measurement of the whole kidney was performed at the initial and latest CT examination. Patients with CKD grade G2 at the time of the initial CT were divided into two groups: a progression group (CKD grade progressed to G3-G5) and a non-progression group. Changes in the renal volume over time were compared between the two groups. RESULTS: The volume of both kidneys measured on initial CT was positively correlated with eGFR (ρ = 0.490, p < 0.001). There was a significant difference in the initial volume of both kidneys among CKD grades (p < 0.001, G1:318.7 ± 60.5 ml, G2:275.5 ± 53.5 ml, G3:233.7 ± 46.9 ml, G4:183.2 ± 22.5 ml, G5:157.7 ± 77.4 ml). When comparing the progression and non-progression groups, the initial volume of both kidneys was significantly smaller in the progression group, compared with the non-progression group (252.0 ± 50.6 ml vs. 278.9 ± 53.7 ml). In addition, the annual reduction volume in both the right and left kidneys was significantly greater in the progression group than in the non-progression group (p < 0.001). CONCLUSION: The automated 3D volumetric CT measurement of the whole kidney has the potential to monitor changes in renal volume over time with changes of the renal function.

Non-neoplastic Liver Lesions after Biliary Stenting: Gadoxetic Acid-enhanced MRI Findings and Clinical association.

BACKGROUND: Non-neoplastic liver lesions show low signal intensity in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) after biliary stenting and require differentiation from liver metastases. OBJECTIVE: The study aimed to evaluate the imaging findings and clinical association of non-neoplastic liver lesions showing hypointensity in the HBP of EOB-MRI after biliary stenting, and assess their differentiation from liver metastases. METHODS: This study included 30 patients who underwent EOB-MRI after biliary stenting for pancreaticobiliary malignancies. Among these, 7 patients had pathologically diagnosed non-neoplastic liver lesions, which appeared hypointense in the HBP, and were categorized into the non-neoplastic group. The remaining 23 patients without non-neoplastic liver lesions were included in the control group. Additionally, 29 patients with liver metastasis were included in the liver metastasis group. Clinical associations and imaging features were compared between the groups. RESULTS: A history of cholangitis and two or more biliary interventional procedures were significantly more frequently observed in the non-neoplastic group (p=0.002 and p=0.01, respectively) than in the control groups. Regarding the imaging findings, the liver-to-lesion signal intensity ratio in the HBP in the liver metastasis group was significantly higher than that in the non-neoplastic group (2.13 vs. 1.53, p=0.002). Additionally, liver metastases were visualized significantly more clearly on diffusion-weighted images (p=0.033) and HBP images (p<0.001) in comparison to non-neoplastic lesions. CONCLUSION: Non-neoplastic liver lesions due to biliary inflammation may be observed in the HBP of EOB-MRI in patients after biliary stenting. These lesions may be associated with a history of cholangitis and repeated biliary intervention procedure, and need to be differentiated from liver metastases.

Automated whole-volume measurement of CT fat fraction of the pancreas: correlation with Dixon MR imaging.

OBJECTIVES: This study aimed to assess the feasibility of pancreatic steatosis quantification by automated whole-volume measurement of the fat fraction of the pancreas on CT in comparison to MRI using proton-density fat fraction (PDFF) techniques. METHODS: Fifty-nine patients who underwent both CT and MRI were analyzed. Automated whole-volume measurement of pancreatic fat on unenhanced CT was performed by a histogram analysis with local thresholding. Three sets of CT fat volume fraction (FVF) (%) values with thresholds of -30 Hounsfield unit (HU), -20 HU and -10 HU were compared to MR-FVF (%) values measured on a PDFF map. RESULTS: The median -30 HU CT-FVF, -20 HU CT-FVF, -10 HU CT-FVF and MR-FVF values of the pancreas were 8.6% (interquartile range (IQR), 11.3), 10.5% (IQR, 13.2), 13.4% (IQR, 16.1) and 10.9% (IQR, 9.7), respectively. The -30 HU CT-FVF (%), -20 HU CT-FVF (%) and -10 HU CT-FVF (%) of the pancreas showed a significant positive correlation with the MR-FVF (%) of the pancreas (ρ = 0.898, p < 0.001, ρ = 0.905, p < 0.001, ρ = 0.909, p < 0.001, respectively). The -20 HU CT-FVF (%) displayed reasonable agreement with the MR-FVF (%) with a low absolute fixed bias (mean difference, 0.32%; limit of agreement from -10.1 to 10.7%). CONCLUSION: The automated whole-volume measurement of the CT fat fraction of the pancreas using the threshold CT attenuation value of -20 HU may be a feasible, non-invasive, and convenient technique for quantifying pancreatic steatosis. ADVANCES IN KNOWLEDGE: CT-FVF value of the pancreas had a positive correlation with the MR-FVF value. The -20 HU CT-FVF may be a convenient technique for quantifying pancreatic steatosis.

Cleaner fish recognize self in a mirror via self-face recognition like humans.

Some animals have the remarkable capacity for mirror self-recognition (MSR), yet any implications for self-awareness remain uncertain and controversial. This is largely because explicit tests of the two potential mechanisms underlying MSR are still lacking: mental image of the self and kinesthetic visual matching. Here, we test the hypothesis that MSR ability in cleaner fish, Labroides dimidiatus, is associated with a mental image of the self, in particular the self-face, like in humans. Mirror-naive fish initially attacked photograph models of both themselves and unfamiliar strangers. In contrast, after all fish had passed the mirror mark test, fish did not attack their own (motionless) images, but still frequently attacked those of unfamiliar individuals. When fish were exposed to composite photographs, the self-face/unfamiliar body were not attacked, but photographs of unfamiliar face/self-body were attacked, demonstrating that cleaner fish with MSR capacity recognize their own facial characteristics in photographs. Additionally, when presented with self-photographs with a mark placed on the throat, unmarked mirror-experienced cleaner fish demonstrated throat-scraping behaviors. When combined, our results provide clear evidence that cleaner fish recognize themselves in photographs and that the likely mechanism for MSR is associated with a mental image of the self-face, not a kinesthetic visual-matching model. Humans are also capable of having a mental image of the self-face, which is considered an example of private self-awareness. We demonstrate that combining mirror test experiments with photographs has enormous potential to further our understanding of the evolution of cognitive processes and private self-awareness across nonhuman animals.

Lobar hepatic steatosis: Association with portal flow hemodynamics evaluated by multiphasic dynamic contrast-enhanced CT.

PURPOSE: This study aimed to evaluate the association of portal flow hemodynamics with lobar hepatic steatosis by means of dynamic contrast-enhanced (DCE) CT. METHODS: The study population consisted of 235 patients, 77 with lobar hepatic steatosis (right, n = 67; left, n = 10), 158 with diffuse hepatic steatosis with (n = 76) and without (n = 82) a focal fatty spared area. CT attenuation values (Hounsfield units: HU) of the liver with and without hepatic steatosis were measured in unenhanced and arterial-phase CT. The contrast enhancement (CE) values were calculated as the difference in HU values between unenhanced and arterial-phase CT. RESULTS: In 67 patients with lobar steatosis of the right lobe, the median CE values of the areas of right lobar steatosis were significantly lower than those of the non-fatty left lobe (13 [IQR 7-19] vs 23 [13-33] HU, P < 0.01), suggesting dominant SMV flow to the right lobe with lobar hepatic steatosis. Conversely, in 10 patients with lobar steatosis of the left lobe, the median CE values of the areas of left lobar steatosis were lower than those of the non-fatty right lobe (15.5 [11.75-21.5] vs 16 [14.5-22] HU); however, this difference was not statistically significant (P = 0.20). In 76 patients with a focal fatty spared area, there were significant differences in the median CE values between hepatic steatosis areas and focal fatty spared areas in the gallbladder fossa group (P = 0.01) and in the segment IV group (P < 0.01). CONCLUSION: Lobar hepatic steatosis may be associated with regional changes of the portal flow hemodynamics (i.e., predominant perfusion from the SMV flow to the lobes with steatosis).

Differential diagnosis of infectious diseases, drug-induced lung injury, and pulmonary infiltration due to underlying malignancy in patients with hematological malignancy using HRCT.

PURPOSE: To differentiate among infectious diseases, drug-induced lung injury (DILI) and pulmonary infiltration due to underlying malignancy (PIUM) based on high-resolution computed tomographic (HRCT) findings from patients with hematological malignancies who underwent chemotherapy or hematopoietic stem cell transplantation. MATERIALS AND METHODS: A total of 221 immunocompromised patients with hematological malignancies who had proven chest complications (141 patients with infectious diseases, 24 with DILI and 56 with PIUM) were included. Two chest radiologists evaluated the HRCT findings, including ground-glass opacity, consolidation, nodules, and thickening of bronchovascular bundles (BVBs) and interlobular septa (ILS). After comparing these CT findings among the three groups using the χ2test, multiple logistic regression analyses (infectious vs noninfectious diseases, DILI vs non-DILI, and PIUM vs non-PIUM) were performed to detect useful indicators for differentiation. RESULTS: Significant differences were detected in many HRCT findings by the χ2 test. The results from the multiple logistic regression analyses identified several indicators: nodules without a perilymphatic distribution [p = 0.012, odds ratio (95% confidence interval): 4.464 (1.355-11.904)], nodules with a tree-in-bud pattern [p = 0.011, 8.364 (1.637-42.741)], and the absence of ILS thickening[p = 0.003, 3.621 (1.565-8.381)] for infectious diseases, the presence of ILS thickening [p = 0.001, 7.166 (2.343-21.915)] for DILI, and nodules with a perilymphatic distribution [p = 0.011, 4.256 (1.397-12.961)] and lymph node enlargement (p = 0.008, 3.420 (1.385-8.441)] for PIUM. CONCLUSION: ILS thickening, nodules with a perilymphatic distribution, tree-in-bud pattern, and lymph node enlargement could be useful indicators for differentiating among infectious diseases, DILI, and PIUM in patients with hematological malignancies.

Pancreatic Steatosis Evaluated by Automated Volumetric CT Fat Fraction of the Pancreas: Association with Severity in COVID-19 Pneumonia.

This study investigated the relationship between the severity of pneumonia based on chest CT findings and that of pancreatic steatosis assessed using an automated volumetric measurement of the CT fat volume fraction (CT-FVF) of the pancreas, using unenhanced three-dimensional CT in polymerase chain reaction (PCR)-confirmed COVID-19 patients. The study population consisted of 128 patients with PCR-confirmed COVID-19 infection who underwent CT examinations. The CT-FVF of the pancreas was calculated using a histogram analysis for the isolation of fat-containing voxels in the pancreas. The CT-FVF (%) of the pancreas had a significantly positive correlation with the lung severity score on CT (ρ = 0.549, p < 0.01). CT-FVF (%) of the pancreas in the severe pneumonia group was significantly higher than that of the non-severe pneumonia group (21.7% vs. 7.8%, p < 0.01). The area under the curve of CT-FVF (%) of the pancreas in predicting the severity of pneumonia on CT was calculated to be 0.82, with a sensitivity of 88% and a specificity of 68% at a threshold for the severity score of 12.3. The automated volumetric measurement of the CT-FVF of the pancreas using unenhanced CT can help estimate disease severity in patients with COVID-19 pneumonia based on chest CT findings.

Platypnea-orthodeoxia syndrome in a patient with ongoing COVID-19.

SARS-CoV-2 infection of the vascular endothelium causes excessive vasodilation. It is important in the rehabilitation of patients with COVID-19 to recognize that increased blood flow in lung lesions at the base of the lung due to vasodilation may cause V/Q mismatch and result in platypnea-orthodeoxia syndrome.

High-resolution CT findings of pulmonary infections in patients with hematologic malignancy: comparison between patients with or without hematopoietic stem cell transplantation.

PURPOSE: To evaluate the high-resolution CT (HRCT) findings of pulmonary infections in patients with hematologic malignancy and compare them between patients with or without hematopoietic stem cell transplantation (HSCT). MATERIALS AND METHODS: A total of 128 patients with hematologic malignancy and pulmonary infection were included in this study. The diagnoses of the patients consisted of bacterial pneumonia (37 non-HSCT cases and 14 HSCT cases), pneumocystis pneumonia (PCP) (29 non-HSCT cases and 11 HSCT cases), and fungal infection other than PCP (20 non-HSCT cases and 17 HSCT cases). Two chest radiologists retrospectively evaluated the HRCT criteria and compared them using chi-squared tests and a multiple logistic regression analysis. RESULTS: According to the multiple logistic regression analysis, nodules were an indicator in HSCT patients with PCP (p = 0.025; odds ratio, 5.8; 95% confidence interval, 1.2-26.6). The centrilobular distribution of nodules was the most frequent (n = 4, 36%) in HSCT patients with PCP. A mosaic pattern was an indicator of PCP in both HSCT and non-HSCT patients. There were no significant differences in other infections. CONCLUSION: The mosaic pattern could be an indicator of PCP in both HSCT and non-HSCT patients. Nodules with centrilobular distribution might be relatively frequent HRCT findings of PCP in HSCT patients.

Further evidence for the capacity of mirror self-recognition in cleaner fish and the significance of ecologically relevant marks.

An animal that tries to remove a mark from its body that is only visible when looking into a mirror displays the capacity for mirror self-recognition (MSR), which has been interpreted as evidence for self-awareness. Conservative interpretations of existing data conclude that convincing evidence for MSR is currently restricted to great apes. Here, we address proposed shortcomings of a previous study on MSR in the cleaner wrasse Labroides dimidiatus, by varying preexposure to mirrors and by marking individuals with different colors. We found that (1) 14/14 new individuals scraped their throat when a brown mark had been provisioned, but only in the presence of a mirror; (2) blue and green color marks did not elicit scraping; (3) intentionally injecting the mark deeper beneath the skin reliably elicited spontaneous scraping in the absence of a mirror; (4) mirror-naive individuals injected with a brown mark scraped their throat with lower probability and/or lower frequency compared to mirror-experienced individuals; (5) in contrast to the mirror images, seeing another fish with the same marking did not induce throat scraping; and (6) moving the mirror to another location did not elicit renewed aggression in mirror-experienced individuals. Taken together, these results increase our confidence that cleaner fish indeed pass the mark test, although only if it is presented in ecologically relevant contexts. Therefore, we reiterate the conclusion of the previous study that either self-awareness in animals or the validity of the mirror test needs to be revised.

Differentiation of pulmonary complications with extensive ground-glass attenuation on high-resolution CT in immunocompromised patients.

PURPOSE: The purpose of this study was to compare the high-resolution CT (HRCT) findings of pulmonary infectious and noninfectious complications with extensive ground-glass attenuation (GGA) in immunocompromised patients. MATERIALS AND METHODS: One hundred fifty-two immunocompromised patients with pulmonary complications that showed extensive GGA (> 50% of the whole lung on HRCT) were included in this study. The diagnoses of the 152 patients were as follows: pneumocystis pneumonia (PCP), n = 82; drug-induced pneumonia, n = 38; bacterial pneumonia, n = 9; cytomegalovirus pneumonia, n = 6; idiopathic pneumonia syndrome, n = 6; diffuse alveolar hemorrhage (DAH), n = 4; fungal infection, n = 3; tuberculosis, n = 2 and pulmonary edema, n = 2. Two chest radiologists retrospectively evaluated the CT criteria, which consisted of 12 findings. RESULTS: The nodule (p = 0.015), the bronchovascular bundle (BVB) thickening (p = 0.001), and the interlobular septum (ILS) thickening (p = 0.002) were significantly infrequent in PCP. The ILS thickening was significantly frequent in drug-induced pneumonia (p < 0.001) though it was also frequent in other noninfectious and infectious diseases. The BVB thickening was significantly frequent in bacterial pneumonia (p = 0.005). The nodule was significantly frequent in DAH (p = 0.049). CONCLUSION: Nodules, BVB thickening, and ILS thickening could be useful HRCT findings for the differential diagnosis of pulmonary complications in immunocompromised patients with extensive GGA.

Treatment strategy for primary lung cancer in a lung highly compressed by giant emphysematous bullae: A case report.

Lung cancer sometimes develops on the wall of a giant emphysematous bulla (GEB). Herein, we describe a rare case in which lung cancer developed in lung tissue compressed by GEBs. A 62-year-old man underwent a computed tomography (CT) scan that revealed two right GEBs. A tumor was suspected in the highly compressed right upper lobe. Since the right bronchus was significantly shifted toward the mediastinum, it was difficult to perform a bronchoscopy. We inserted thoracic drains into the GEBs, and a subsequent CT scan revealed re-expansion of the remaining right lung and a 3.3 cm tumor in the right upper lobe. The shift of the right bronchus was improved, and bronchoscopy was performed. The tumor was diagnosed as non-small cell lung cancer (NSCLC). Additionally, the GEBs were found to have originated from the right lower lobe. We performed a right upper lobectomy, mediastinal lymph node dissection, and bullectomy of the GEBs via video-assisted thoracoscopic surgery. In preoperative evaluation of a GEB, assessing re-expansion and lung lesions of the remaining lung is important, and intracavity drainage of a GEB may be useful. KEY POINTS: Significant findings of the study Cancer that develops in lung tissue highly compressed by a giant emphysematous bulla is difficult to diagnose. In the preoperative evaluation of a giant emphysematous bulla, assessing re-expansion and lung lesions of the remaining lung is important. What this study adds After performing intracavity drainage of a giant emphysematous bulla, the remaining lung re-expands, and the bronchial shift improves; subsequently, bronchoscopy makes it possible to diagnose lung cancer in the remaining lung.

Differential diagnosis of pulmonary infections in immunocompromised patients using high-resolution computed tomography.

OBJECTIVES: The aims of this study were to compare the high-resolution computed tomography (HRCT) findings of pulmonary infections in immunocompromised patients and to assess the usefulness of HRCT in the differential diagnosis of these infections. METHODS: A total of 345 immunocompromised patients with pulmonary infections were included in this study. The diagnoses of the patients consisted of bacterial pneumonia (123 cases), pneumocystis pneumonia (PCP) (105 cases), fungal pneumonia (80 cases), tuberculosis (15 cases), cytomegalovirus pneumonia (11 cases), and septic embolism (11 cases). Two chest radiologists retrospectively evaluated the computed tomography (CT) images, which consisted of 22 findings including ground-glass attenuation, consolidation, nodules, and thickening of the bronchial wall and interlobular septum. Associations between the CT criteria and infections were investigated using χ2 test; multiple logistic regression analyses were conducted to identify the significant indicator for each infection. The area under the curve (AUC) of each model was calculated. RESULTS: Bronchial wall thickening was a significant indicator for bacterial pneumonia (p = 0.002; odds ratio [OR], 2.341; 95% confidence interval [CI], 1.378-3.978). The presence of a mosaic pattern and the absence of nodules were significant indicators for PCP (p < 0.001; OR, 9.808; 95% CI, 4.883-13.699, and p < 0.001; OR, 6.834; 95% CI, 3.438-13.587, respectively). The presence of nodules was a significant indicator for fungal infection (p = 0.005; OR, 2.531; 95% CI, 1.326-4.828). The AUC for PCP was the highest (0.904). CONCLUSIONS: HRCT findings are potentially useful for the differential diagnosis of some pulmonary infections in immunocompromised patients. KEY POINTS: • Differential diagnosis of pulmonary infections in immunocompromised patients could be established with the help of high-resolution computed tomography. • Bronchial wall thickening was a significant indicator for bacterial pneumonia. • The presence of a mosaic pattern and the absence of nodules were significant indicators for pneumocystis pneumonia.

Predicting the response to a bronchodilator in patients with airflow obstruction and lung cancer.

BACKGROUND: The aim of the present study was to clarify the predictors of the response of patients with resectable lung cancer and untreated airflow obstruction to tiotropium, an antimuscarinic bronchodilator. METHODS: Tiotropium was administered to 29 preoperative patients with untreated airflow obstruction. The forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were measured before and after the introduction of tiotropium. The response to tiotropium was determined based on the percentage gain in the FEV1. The volume of the total lung area (TLV) and the low-attenuation area (LAA) was measured by deep inspiratory computed tomography based on the predefined thresholds for attenuation values. RESULTS: The introduction of tiotropium resulted in a 15% gain in the FEV1 (P < 0.001). A univariate regression analysis revealed that the FVC/TLV was the best predictor of the gain in FEV1, followed by the FEV1/FVC. Based on the results of a multiple regression analysis, a regression equation to predict a gain in the FEV1 was generated using the FVC, TLV, and LAA. A receiver operating characteristic curve analysis revealed that this equation led to the highest area under the curve for predicting a major response to tiotropium, followed by the FVC/TLV and FEV1/FVC. Postoperatively, six of the 20 minor responders experienced a progression of dyspnea. In contrast, none of the major responders experienced a progression of dyspnea (P < 0.05). CONCLUSIONS: We developed an equation for predicting the response to tiotropium using parameters obtained from spirometry and quantitative computed tomography. A large-scale study to validate the usefulness of this equation is warranted.

Grading of Emphysema Is Indispensable for Predicting Prolonged Air Leak After Lung Lobectomy.

BACKGROUND: The aim of this study was to assess the utility of quantitative computed tomography-based grading of emphysema for predicting prolonged air leak after thoracoscopic lobectomy. METHODS: A consecutive series of 284 patients undergoing thoracoscopic lobectomy for lung cancer was retrospectively reviewed. Prolonged air leak was defined as air leaks lasting 7 days or longer. The grade of emphysema (emphysema index) was defined by the proportion of the emphysematous lung volume (less than -910 HU) to the total lung volume (-600 to -1,024 HU) by a computer-assisted histogram analysis of whole-lung computed tomography scans. RESULTS: The mean length of chest tube drainage was 1.5 days. Fifteen patients (5.3%) presented with prolonged air leak. According to a receiver-operating characteristics curve analysis, the emphysema index was the best predictor of prolonged air leak, with an area under the curve of 0.85 (95% confidence interval: 0.73 to 0.98). An emphysema index of 35% or greater was the best cutoff value for predicting prolonged air leak, with a negative predictive value of 0.99. The emphysema index was the only significant predictor for the length of postoperative chest tube drainage among conventional variables, including the pulmonary function and resected lobe, in both univariate and multivariate analyses. Prolonged air leak resulted in an increased duration of hospitalization (p < 0.001) and was frequently accompanied by pneumonia or empyema (p < 0.001). CONCLUSIONS: The grade of emphysema on computed tomography scan is the best predictor of prolonged air leak that adversely influences early postoperative outcomes. We must take new measures against prolonged air leak in quantitative computed tomography-based high-risk patients.

The Validation of a No-Drain Policy After Thoracoscopic Major Lung Resection.

BACKGROUND: The omission of postoperative chest tube drainage may contribute to early recovery after thoracoscopic major lung resection; however, a validation study is necessary before the dissemination of a selective drain policy. METHODS: A total of 162 patients who underwent thoracoscopic anatomical lung resection for lung tumors were enrolled in this study. Alveolar air leaks were sealed with a combination of bioabsorbable mesh and fibrin glue. The chest tube was removed just after the removal of the tracheal tube in selected patients in whom complete pneumostasis was obtained. RESULTS: Alveolar air leaks were identified in 112 (69%) of the 162 patients in an intraoperative water-seal test performed just after anatomical lung resection. The chest tube could be removed in the operating room in 102 (63%) of the 162 patients. There were no cases of 30-day postoperative mortality or in-hospital death. None of the 102 patients who did not undergo postoperative chest tube placement required redrainage for a subsequent air leak or subcutaneous emphysema. The mean length of postoperative hospitalization was shorter in patients who had not undergone postoperative chest tube placement than in those who had. The omission of chest tube placement was associated with a reduction in the visual analog scale for pain from postoperative day 0 until postoperative day 3, in comparison with patients who underwent chest tube placement. CONCLUSIONS: The outcome of our validation cohort revealed that a no-drain policy is safe in selected patients undergoing thoracoscopic major lung resection and that it may contribute to an early recovery.