Is Free Breathing Possible During Computed Tomography-Guided Percutaneous Transthoracic Lung Biopsy? The Clinical Experience in 585 Cases.

OBJECTIVE: The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing. METHODS: We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis. RESULTS: Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P < 0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P < 0.001), lower lobe location (P < 0.001), prone position (P = 0.004), and visible motion artifact (P < 0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P < 0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P < 0.001) were risk factors for hemoptysis. CONCLUSIONS: Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Assessing Vessel Tone during Coronary Artery Spasm by Dual-Acquisition Multidetector Computed Tomography Angiography.

BACKGROUND: Diminished vascular tone is an established biomarker of heart damage. Little is known about the extent of coronary vessel tone (CVT) with spasm as assessed by dual-acquisition multidetector computed tomography angiography (MCTA) in patients with vasospastic angina (VSA). OBJECTIVE: We evaluated the CVT modulated by intravenous nitrate injection (INI) using MCTA imaging in VSA patients. METHODS: Twenty-one VSA patients (60 ± 9 years; 76% males) who underwent initial MCTA (without morning vasodilation), followed by an intracoronary ergonovine provocation test were included. Within 3 days after the initial MCTA patients received INI followed by 28-vessel segment spasm analyzed by MCTA 3D software, applying the following formula as the definition of CVT index (CVTI): (CSAIV nitrate - CSAinitial/CSAIV nitrate) ×100 %, where CSA is the cross-sectional area. RESULTS: Compared to the initial MCTA measures, the INI provocation resulted in the significant increase of average diameter and CSA at the spasm site (2.60 mm [2.11-3.16] vs. 1.42 mm [1.13-2.13]; 5.37 mm2 [3.67-7.54] vs. 1.62 mm2 [1.02-3.02]; p < 0.001). The CVTI at the spastic segments was higher than at the proximal reference segments (41.0% [21.8-52.3] vs. 18.8% [5.9-26.6] for CVTI diameter; 65.1% [38.6-77.0] vs. 33.9% [5.2-48.1] for CVTI CSA, respectively). To predict VSA, the cut-off value for CVTI diameter was 38.6% (AUC 0.777; 95% CI 0.653-0.901) and 62.5% (AUC 0.779; 95% CI 0.657-0.902) for CVTI CSA in a receiver-operating characteristic curve analysis, with 57.1% sensitivity and 92.9% specificity. CONCLUSIONS: This novel imaging technique for assessing CVT by dual-acquisition MCTA after applying INI provocation is suitable for the detection of coronary artery spasm in patients with VSA.

Noninvasive detection of coronary vasospastic angina using a double-acquisition coronary CT angiography protocol in the presence and absence of an intravenous nitrate: a pilot study.

OBJECTIVES: To evaluate the feasibility of a double-acquisition coronary CT angiography (CCTA) protocol in the presence and absence of an intravenous (IV) vasodilator infusion for detecting vasospastic angina. METHODS: Twenty patients with a high clinical probability of vasospastic angina were enrolled. All subjects underwent baseline CCTA without a vasodilator in the early morning followed by a catheterized coronary angiography with ergonovine provocation test. Within 3 days, all subjects underwent repeat CCTA during a continuous IV infusion of nitrate. Vasospastic angina as detected by CCTA was defined as significant stenosis (≥50 %) with negative remodelling without definite plaques or diffuse small diameter (<2 mm) of a major coronary artery with a beaded appearance on baseline CT that completely dilated on IV nitrate CT. The CCTA results were compared to the catheterized ergonovine provocation test as the reference standard. RESULTS: Among 20 patients, the catheterized ergonovine provocation test detected vasospasm in 15 patients. The sensitivity, specificity, positive predictive value and negative predictive value of CCTA in a per-patient-based analysis were 73, 100, 100 and 56 %, respectively. CONCLUSIONS: Double-acquisition CCTA in the presence and absence of IV infusion of nitrate allows noninvasive detection of vasospastic angina with moderate sensitivity and high specificity. KEY POINTS: • Limited data exist regarding the efficacy of CCTA in detecting vasospastic angina. • We propose a double-acquisition CCTA protocol with and without IV nitrate injections. • This protocol provides 100% specificity and moderate sensitivity (73%) in spasm detection.

Takayasu arteritis: assessment of coronary arterial abnormalities with 128-section dual-source CT angiography of the coronary arteries and aorta.

PURPOSE: To evaluate coronary arterial lesions and to assess their correlation with clinical findings in patients with Takayasu arteritis (TA) by using coronary computed tomographic (CT) angiography. MATERIALS AND METHODS: This retrospective study was approved by the hospital internal review board, and informed consent was waived. A total of 111 consecutive patients with TA (97 female, 14 male; mean age, 44 years ± 13.8 [standard deviation]; age range, 14-74 years) underwent CT angiography of the coronary arteries and aorta with 128-section dual-source CT. CT angiographic, clinical, and laboratory findings of each patient were retrospectively reviewed. Statistical differences between coronary CT angiographic findings and clinical parameters were examined with univariate analysis. RESULTS: Of 111 patients, 32 (28.8%) had cardiac symptoms and the remaining 79 (71.2%) had no cardiac symptoms. Fifty-nine patients (53.2%) had coronary arterial lesions at coronary CT angiography. Three main radiologic features were detected: coronary ostial stenosis (n = 31, 28.0%), nonostial coronary arterial stenosis (n = 41, 36.9%), and coronary aneurysm (n = 9, 8.1%). Coronary artery ostial or luminal stenosis of 50% or more or coronary aneurysms were observed in 26 (23.4%) patients with TA. Patients with coronary arterial abnormalities at coronary CT angiography had higher incidences of hypertension (P = .02), were older at the time of CT (P = .01), and had longer duration of TA (P = .02) than those without coronary artery abnormalities. The presence of cardiac symptoms, disease activity, and other comorbidities was not associated with differences in coronary artery involvement. CONCLUSION: In patients with TA, there is a high prevalence of coronary arterial abnormalities at coronary CT angiography, regardless of disease activity or symptoms. Thus, coronary CT angiography may add information on coronary artery lesions in patients with TA.

An initial randomised study assessing free-breathing CCTA using 320-detector CT.

OBJECTIVES: To evaluate the feasibility of free-breathing coronary computed tomography angiography (CCTA) in adults using with a 320-detector multidetector CT (MDCT). METHODS: In 74 patients who underwent CCTA, 37 CCTA examinations were performed during free-breathing, and the remaining 37 CCTA examinations were produced with the standard breath-holding method. The quality scores for 16 segments of all coronary arteries were analysed and defined as: 1 (excellent), 2 (good), and 3 (poor). The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and effective radiation dose of each image were compared between the two methods. RESULTS: No significant differences were observed in the quality scores between the breath-holding and free-breathing methods (1.10 ± 0.31 vs. 1.12 ± 0.33; P = 0.443). The SNR and CNR were not significantly different between the two methods. The overall mean effective radiation dose revealed no significant difference between the two methods (P = 0.585). CONCLUSIONS: Free-breathing CCTA using 320-detector MDCT showed no significant difference in image quality compared with standard breath-holding CCTA. For patients with difficulties of breath-holding or non-negligible apnoea-related heart rate variability, free-breathing CCTA can be an alternative solution for coronary artery evaluation. KEY POINTS: • Cardiac CT is becoming widely used and some patients are inevitably breathless. • Multidetector CT (e.g. 320) offers new opportunities for the breathless patient. • Free breathing images yielded similar image quality to those obtained using breath-holding. • However, a possibility of higher radiation dose precludes its routine application.

Multidetector CT findings of primary pleural angiosarcoma : a systematic review, an additional cases report.

BACKGROUND: To demonstrate and analyze the relatively common imaging findings in this rare primary pleural angiosarcoma (PPA). CASE PRESENTATION: Three cases of PPA, proven by video-assisted thoracic surgery biopsies are retrospectively reviewed. Patients were all male. Age ranges from 65 to 75 years old age (mean; 69). Major chief complaints were dyspnea and chest pain. One has a history of colon cancer, the other has a tuberculosis history and the other has no known history. Multidetector chest CT and PET CT were all done. Immunohistochemical studies were performed including CD31, CD34, or factor VIII-related antigen, vimentin, and cytokeratin. We also review the literatures on recently published PPA. All masses were from 1 to 10 cm. All three patients had multiple pleural based masses, which were ovoid in shape with relatively sharp margin in unilateral hemithorax. Multiple small circumscribed pleural masses are limited in the pleural space in two patients, whereas two, huge lobulated masses about up to 10 cm were present with pleural and extrapleural involvement in one patient. In two patients with pleural mass only, multiple pleural masses were only seen in parietal pleura in one patient and were in both visceral and parietal pleura in one patient. Pleural effusion were found in one side in one patient and in both sides in one patient. One angiosarcoma was arised from chronic tuberculotic pleurisy sequelae. All pleural masses are heterogenous with irregular internal low densities in all patients. Hematogenous metastases were found in liver, vertebra, rib in one patient, and were in lungs with mediastinal lymph node metastases in the other patient. Three patients survived for longer than 3months after diagnosis, but continued to deteriorate rapidly. Two patients underwent chemotherapy after surgical excision, and the other one with multiple metastases treated chemotherapy after CT-guided biopsy, but eventually all died. As a result of comparative analysis of a total of 13 patients' images including 10 cases previously published, there was pleural effusion in all except 2 cases. CONCLUSIONS: PPA were all necrotic without any vascularized enhancing nature, and manifested as unilateral circumscribed or localized pleural-based masses.

Novel macrocyclic C-aryl glucoside SGLT2 inhibitors as potential antidiabetic agents.

Novel macrocyclic C-aryl glucoside SGLT2 inhibitors were designed and synthesized. Two different synthetic routes of macrocyclization were adopted to prepare novel ansa SGLT2 inhibitors. Among the compounds tested, [1,7]dioxacyclopentadecine macrocycles possessing methylthiophenyl at the distal ring 40 or ethoxyphenyl at the distal ring 23 showed the best in vitro inhibitory activity in this series to date (40, IC(50)=0.778 nM and 23, IC(50)=0.899 nM) against hSGLT2.

A Case of Coronary Sinus Atresia with a Total Anomalous Cardiac Venous Drainage to the Left Atrium without Persistent Left Superior Vena Cava: Imaging Findings on Cardiac CT.

The coronary sinus (CS) is the venous drainage system of the heart. CS ostium atresia is a rarely seen cardiac malformation. Congenital atresia of the CS is usually found together with persistent left superior vena cava (LSVC) and other cardiac malformations. However, isolated congenital atresia of the CS is very rare. We present a rare case of isolated congenital atresia of the CS connecting the left atrium and coronary veins without persistent LSVC in a 58-year-old female.

Levoatriocardinal Vein Combined with Pulmonary Venous Varix Mimicking Arteriovenous Malformations: A Case Report.

The levoatriocardinal vein is an uncommon pulmonary venous abnormality that connects the left atrium or pulmonary vein with the systemic vein. It is distinct from partial anomalous pulmonary venous return in that the former forms a connection with the left atrium through the normal pulmonary vein whereas the latter involves pulmonary venous drainage to the systemic vein. Herein, we describe a case of the levoatriocardinal vein initially misdiagnosed as a pulmonary arteriovenous malformation using chest radiography and chest CT. The levoatriocardinal vein combined with pulmonary venous varix was confirmed using pulmonary angiography. To the best of our knowledge, this unusual coexistence of the levoatriocardinal vein and pulmonary venous varix has not been reported in English literature.

Incidentally Detected Pericardial Defect in a Patient with Pneumothorax as Confirmed on Video-Assisted Thoracoscopic Surgery.

Congenital defects of the pericardium, which are generally asymptomatic, are rare disorders characterized by complete or partial absence of the pericardium. Here, we report a rare case of a 19-year-old male who was incidentally diagnosed with congenital absence of the left pericardium during examination for symptoms of pneumothorax. Chest radiography and computed tomography revealed a collapsed left lung without any evidence of trauma, no unusual findings of free air spaces along the right side of the ascending aorta, heart shifted toward the left side of the thorax, and a shallow chest. Subsequent thoracoscopy confirmed the absence of the left pericardium and displacement of the heart toward the left thoracic cavity. We further discuss the correlation between radiologic images and surgical findings of a congenital pericardial defect associated with spontaneous pneumothorax.

CT Follow-Up of Postoperative Bronchopleural Fistula: Risk Factors for Progression to Chronic Complicated Infection.

Purpose: We evaluated the risk factors for progression to chronic complicated bronchopleural fistula (BPF) after pulmonary resection using follow-up CT. Materials and Methods: We retrospectively reviewed 45 cases with BPF that had undergone pulmonary resection during 2010-2018. We compared the clinical and radiological characteristics of those with complicated BPF (n = 24) and those without complicated (sterilized) BPF (n = 21). The clinical and radiological risk factors for progression to chronic complicated BPF were examined by logistic regression analysis. Results: The thickness of the pleural cavity wall (p = 0.022), the size of the pleural cavity (p = 0.029), and the size increase of BPF on follow-up (p = 0.012) were significantly different between the two groups. The risk factors for progression to chronic complicated BPF were age > 70 years (odds ratio, 6.43; 95% confidence interval, 1.2-33.7), the thickness of the cavity wall > 5 mm (odds ratio, 52.5; 95% confidence interval, 5.1-545.4), and an increase in the size of the pleural cavity on follow-up CT (odds ratio, 12.5; 95% confidence interval, 2.1-73.5), only in the univariate analysis. Conclusion: The risk factors for progression to chronic complicated BPF can be evaluated using follow-up CT.

The Effects of a Vasodilator on Transluminal Attenuation Gradient at Coronary Computed Tomography Angiography.

OBJECTIVE: To evaluate the effects of vasodilators on contrast enhancement and transluminal attenuation gradient (TAG) of coronary arteries at coronary computed tomography angiography (CCTA). MATERIALS AND METHODS: We retrospectively reviewed CCTA scans of patients who underwent double-acquisition CCTA; CCTA without a vasodilator, and CCTA during a intravenous (IV) infusion of nitrate. Among them, we enrolled 19 patients who had no significant atherosclerotic lesions or coronary spasms. In the control group, 28 patients were enrolled who showed normal coronary arteries on CCTA, which was acquired by a conventional method (sublingual vasodilator). We measured the TAG and Hounsfield units for each of the three major epicardial coronary arteries (reported as 'ProxHU') and then compared the results between the nitrate administration methods (CT without vasodilator [CTpre], CT with IV vasodilator [CTiv], and CT with sublingual vasodilator [CTsub]). RESULTS: The mean TAG showed a significant difference between the coronary arteries (right coronary artery [RCA] > left anterior descending artery [LAD] > left circumflex artery [LCX], p < 0.05), while there was no difference in ProxHU of each coronary artery in all three types of nitrate administration methods (p > 0.05). The TAG of CTpre group showed steeper slope than those of vasodilator groups (CTiv and CTsub) on LAD and LCX ([LAD: CTpre = -22.1 ± 6.66, CTiv = -16.76 ± 5.78, and CTsub = -16.47 ± 5.78, p = 0.005], [LCX: CTpre = -31.26 ± 17.43, CTiv = -23.74 ± 14.06, and CTsub = -20.94 ± 12.15, p = 0.051]), while that of RCA showed no significant differences (p = 0.600). When comparing proxHU, CTiv showed higher proxHU than that of CTpre or CTsub, especially on LCX (CTpre = 426.7 ± 68.3, CTiv = 467.9 ± 84.9, and CTsub = 404.9 ± 63.3, p = 0.013). ProxHU showed a negative correlation with TAG on all three of methods (r = -0.280, p < 0.001). CONCLUSION: TAG in CCTA was significantly affected by vasodilator administration. Both TAG and ProxHU of coronary arteries tend to increase with vasodilator administration on CCTA.

Significance of baseline computed tomography assessment for predicting the pulmonary fibrosis during the course of chemotherapy-induced pneumonitis.

BACKGROUND: The purpose of our study is to evaluate risk factors for the development of pulmonary fibrosis in the baseline computed tomography (CT) during the course of chemotherapy-induced pneumonitis (CIP). METHODS: We retrospectively identified 80 cases of CIP by clinical, radiological, and pathological findings. When fibrosis developed during the follow-up, the extent of pulmonary fibrosis was evaluated at final follow-up CT in terms of a 5% volumetric score for six zones. Univariate and multivariate analyses were performed to identify the clinical and radiological risk factors for the development of fibrosis and severe fibrosis over 11% in extent. RESULTS: Fibrosis occurred in 26 of the 80 total patients (32.5%) during a mean 5.6 months of follow up. Risk factors for developing fibrosis were revealed as preexisting interstitial lung disease (ILD) and moderate to severe emphysema in multivariate analysis (OR = 10.12, 95% CI = 2.35-43.66, and OR = 12.85, 95% CI = 2.81-58.82, respectively). Risk factors for developing severe fibrosis over 11% in extent were revealed as a moderate to severe emphysema (OR = 5.78, 95% CI = 1.07-31.26) in multivariate analysis. CONCLUSIONS: Moderate to severe emphysema as well as preexisting ILD visible on baseline CT are risk factors for developing pulmonary fibrosis in the course of CIP. Thin-section CT may be helpful to predict the risk of pulmonary fibrosis before administering chemotherapy.

Four cases of a cerebral air embolism complicating a percutaneous transthoracic needle biopsy.

A percutaneous transthoracic needle biopsy is a common procedure in the practice of pulmonology. An air embolism is a rare but potentially fatal complication of a percutaneous transthoracic needle biopsy. We report four cases of a cerebral air embolism that developed after a percutaneous transthoracic needle biopsy. Early diagnosis and the rapid application of hyperbaric oxygen therapy is the mainstay of therapy for an embolism. Prevention is the best course and it is essential that possible risk factors be avoided.

Lymph Node Metastasis after Spontaneous Regression of Non-Small Cell Lung Cancer.

Spontaneous regression of lung cancer is a very rare and poorly understood phenomenon. A 64-year-old man presented to Dong-A University Hospital with a shrunken nodule in the right lower lobe. Although the nodule showed a high likelihood of malignancy on needle aspiration biopsy, the patient refused surgery. The nodule spontaneously regressed completely in the next 17 months. However, the subcarinal lymph node was found to be enlarged 16 months after complete regression was observed. We pathologically confirmed metastasis of squamous cell carcinoma and performed neoadjuvant chemotherapy, surgery, and adjuvant chemoradiation. Regardless of tumor size reduction, it is preferable to perform surgery aggressively in cases of operable lung cancer.

Analysis of the time-velocity curve in phase-contrast magnetic resonance imaging: a phantom study.

The aim of this study was to analyze the characteristics of time-velocity curve acquired by phase-contrast magnetic resonance imaging (PC-MRI) using an in-vitro flow model as a reference for hemodynamic studies. The time- velocity curves of the PC-MRI were compared with Doppler ultrasonography (US) and also compared with those obtained in the electromagnetic flowmeter. The correlation between techniques was analyzed using an electromagnetic flowmeter as a reference standard; the maximum, minimum, and average velocities, full-width at half-maximum (FWHM), and ascending gradient (AG) were measured from time-velocity curves. The correlations between an electromagnetic flowmeter and the respective measurement technique for the PC-MRI and Doppler US were found to be high (mean R2 > 0.9, p < 0.05). These results indicate that these measurement techniques are useful for measuring blood flow information and reflect actual flow. The PC-MRI was the best fit for the minimum velocity and FWHM, and the maximum velocity and AG were the best fit for Doppler US. The PC-MRI showed lower maximum velocity value and higher minimum velocity value than Doppler US. Therefore, PC-MRI demonstrates more obtuse time-velocity curve than Doppler US. In addition, the time- velocity curve of PC-MRI could be calibrated by introducing formulae that can convert each measurement value to a reference standard value within a 10% error. The PC-MRI can be used to estimate the Doppler US using this formula.

Inter-observer agreement in identifying traction bronchiectasis on computed tomography: its improvement with the use of the additional criteria for chronic fibrosing interstitial pneumonia.

PURPOSE: To assess inter-observer variability in identifying traction bronchiectasis on computed tomography (CT) using additional criteria for chronic fibrosing interstitial pneumonia. METHODS: Seven experts categorized CT image set representing 39 patients into three groups on the basis of the presence of traction bronchiectasis, using a three-point scale: 3-definitely/probably yes; 2-possibly yes; and 1-definitely/probably no. This scale served as a reference standard. The image set included cases of chronic fibrosing interstitial pneumonia, non-interstitial lung disease, and difficult-to-determine cases. Forty-eight observers similarly assessed the same image set, first according to the Fleischner Society definition, and second with additional criteria, in which traction bronchiectasis was observed exclusively in chronic fibrosing interstitial pneumonia. The agreement level between the reference standard and each observer's evaluation in each session was calculated using weighted kappa values which were compared between the two sessions using a paired t test. RESULTS: The mean weighted kappa value for all observers was significantly higher in the second reading session (mean 0.75) than in the first reading session (mean 0.62) (p < 0.001). CONCLUSION: Inter-observer agreement in identifying traction bronchiectasis improves when using the additional criteria which specify chronic fibrosing interstitial pneumonia as the underlying disease.

Capsaicin prevents ethanol-induced teratogenicity in cultured mouse whole embryos.

Prenatal exposure to alcohol promotes the level of reactive oxygen species within embryos and results in developmental disorders. In this study, we investigated the effect of capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), the major pungent ingredient in red peppers, on ethanol-induced teratogenicity in mouse embryos (embryonic days 8.5-10.5). In response to ethanol administration (1.0 microl/ml), developmental parameters such as yolk sac circulation, allantois, heart, hindbrain, midbrain, forebrain, otic and optic systems, branchial bar, olfactory system, forelimb, hindlimb, and somites decreased significantly in comparison with those of control group (p<0.05). However, the concurrent administration of capsaicin (1 x 10(-8) microg/ml or 1 x 10(-7) microg/ml) and ethanol significantly ameliorated most of the morphological scores excepting yolk sac circulation and hindlimb scores (p<0.05). Furthermore, the levels of superoxide dismutase activity and cytoplasmic glutathione peroxidase and phospholipid hydroperoxide glutathione peroxidase mRNAs in the ethanol-treated embryos recovered to the levels observed in control embryos by capsaicin co-administration. These results indicate that capsaicin has a protective effect against ethanol-induced teratogenicity via an antioxidative activity.

Pulmonary paraganglioma manifesting as an endobronchial mass.

Thoracic paragangliomas comprise only 1-2% of all paragangliomas, including the adrenal pheochromocytomas, and these tumors are mostly found in the mediastinal compartments (1). To the best of our knowledge, there is only one case report in the pathology literature of endobronchial involvement by a primary pulmonary paraganglioma (2). We report here on the CT and bronchoscopic findings of a case of pathologically proven endobronchial paraganglioma in a 37-year-old woman. In our case, bronchoscopy and CT demonstrated an endobronchial hypervascular mass, which indicated the presence of carcinoid or hypervascular metastasis based on the known incidence of such tumors.

Effect of Hybrid Kernel and Iterative Reconstruction on Objective and Subjective Analysis of Lung Nodule Calcification in Low-Dose Chest CT.

Objective: To evaluate the differences in subjective calcification detection rates and objective calcium volumes in lung nodules according to different reconstruction methods using hybrid kernel (FC13-H) and iterative reconstruction (IR). Materials and Methods: Overall, 35 patients with small (< 4 mm) calcified pulmonary nodules on chest CT were included. Raw data were reconstructed using filtered back projection (FBP) or IR algorithm (AIDR-3D; Canon Medical Systems Corporation), with three types of reconstruction kernel: conventional lung kernel (FC55), FC13-H and conventional soft tissue kernel (FC13). The calcium volumes of pulmonary nodules were quantified using the modified Agatston scoring method. Two radiologists independently interpreted the role of each nodule calcification on the six types of reconstructed images (FC55/FBP, FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D). Results: Seventy-eight calcified nodules detected on FC55/FBP images were regarded as reference standards. The calcium detection rates of FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D protocols were 80.7%, 15.4%, 6.4%, 52.6%, and 28.2%, respectively, and FC13-H/AIDR-3D showed the smallest calcium detection rate. The calcium volume varied significantly with reconstruction protocols and FC13/AIDR-3D showed the smallest calcium volume (0.04 ± 0.22 mm3), followed by FC13-H/AIDR-3D. Conclusion: Hybrid kernel and IR influence subjective detection and objective measurement of calcium in lung nodules, particularly when both techniques (FC13-H/AIDR-3D) are combined.