Low-dose Computed Tomography Group Research Articles

Feasibility analysis of low-dose CT with asynchronous quantitative computed tomography to assess vBMD

BackgroundTo explore the feasibility of low-dose computed tomography (LDCT) with asynchronous quantitative computed tomography (asynchronous QCT) for assessing the volumetric bone mineral density (vBMD).Methods416 women patients, categorized into 4 groups, were included and underwent chest CT examinations combined with asynchronous QCT, and CT scanning dose protocols (LDCT or CDCT) were self-determined by the participants. Radiation dose estimations were retrieved from patient protocols, including volume CT dose index (CTDIvol) and dose-length-product (DLP), and then calculated effective dose (ED). Delimiting ED by 1.0 mSv, chest CT examinations were categorized into 2 groups, LDCT group and CDCT group. vBMD of T12-L2 was obtained by transferring the LDCT and CDCT images to the QCT workstation, without extra radiation.ResultsThere was no difference of vBMD among 4 age groups in LDCT group (P = 0.965), and no difference in CDCT group (P = 0.988). In LDCT group and CDCT group, vBMD was not correlated to mAs, CTDIvol and DLP (P > 0.05), respectively. Between LDCT group and CDCT group, there was no difference of vBMD (P ≥ 0.480), while differences of mAs, CTDIvol and DLP.ConclusionThere was no difference of vBMD between LDCT group and CDCT group and vBMD was not correlated to mAs. While screening for diseases such as lung cancer and mediastinal lesions, LDCT combined with asynchronous QCT can be also used to assess vBMD simultaneously with no extra imaging equipment, patient visit time, radiation dose and no additional economic cost.

Pulmonary Nodules, Lung Cancer Screening, and Lung Cancer in the Medicare Population

Early detection of lung cancer through management of pulmonary nodules (PNs) may reduce lung cancer mortality. We assessed the relationship between PNs and lung cancer. How common are PNs in the Medicare population? What is the rate of lung cancer after detection of PNs? What is the relative proportion of early-stage lung cancer diagnosed after reporting of PNs vsthrough low-dose CT (LDCT) scan screening? Using the Surveillance Epidemiology and End Results Program-Medicare database, we defined two cohorts: those in the 5%sample with≥ 12months of Medicare Parts A and B coverage from 2014 through 2019 (5%sample cohort) and those with a diagnosis of lung cancer from 2015 through 2017 with coverage for the prior 18-month period (lung cancer cohort). We defined PNs as chest CT scans with accompanying codes of 793.11 (International Classification of Diseases [ICD], Ninth Revision) or R91.1 (ICD, Tenth Revision) denoting a solitary PN. Patients in the lung cancer cohort were classified by whether they had undergone LDCT scan screening and whether they had a diagnosis of PN or neither (reference) within 18months before diagnosis. We compared cancer stage and survival across groups. Of 627,547 patients in the 5%sample cohort, 5.0%demonstrated PNs over median of 5.0 years of follow-up. Cumulative 1- and 2-year lung cancer rates after initial PN diagnosis were 3.2%and 4.7%, respectively. Of 44,194 patients in the lung cancer cohort, 15.7%, 2.9%, and 81.4%were in the PN, LDCT scan, and reference groups, respectively. Of patients in the PN, LDCT scan, and reference groups, 58.1%, 50.3%, and 24.4%respectively, had disease of a localized stage. Among all patients with localized disease, 30.0%and 4.9%were in the PN and LDCT scan and groups, respectively. Three-year lung cancer-specific survival rates were 75.0%, 75.6%, and 49.4%for the PN, LDCT scan, and reference groups. Patients with lung cancer who received a diagnosis after identification of PNs tended to have localized disease. Of all patients with localized disease, almost one-third had PNs that were diagnosed previously, compared with 5%of patients who had undergone LDCT scan screening. PNs represent a relatively common presentation of potentially curable lung cancer.

Postoperative surveillance using low-dose computed tomography for non-small-cell lung cancer.

We retrospectively analysed the surgical prognosis of patients with pathological stage I non-small-cell lung cancer (NSCLC) who after complete resection underwent low-dose computed tomography (LDCT) or conventional CT as postoperative surveillance. We investigated 416 patients who underwent lobectomy or segmentectomy between January 2013 and December 2016. We compared the prognosis between the LDCT and conventional CT groups using the propensity score-matched analysis. The median follow-up period was 57 months. Cancer recurrence occurred in 47 patients (11.3%). In the entire cohort (n = 416), recurrence-free survival (RFS) and overall survival (OS) were better in the LDCT group (P = 0.001 and 0.002, respectively). Both intrathoracic recurrence and distant metastasis were higher in the conventional group (P = 0.015 and 0.009, respectively). However, there was no statistical difference in the factors leading to recurrence detection (routine radiological examination, symptoms and elevated tumour markers: all P > 0.05). Both groups were matched using a ratio of 1:1. The area under the receiver operating characteristic curve was 0.788. A total of 226 patients were successfully matched. After matching, there was no statistical difference between the 2 groups for RFS and OS (P = 0.263 and 0.226). There were also no statistical differences in recurrence rate, the factors leading to recurrence detection or recurrence site (all P > 0.05). After using propensity score matched, RFS and OS did not differ significantly between LDCT and conventional CT groups. Retrospective comparisons suggest no disadvantages of using LDCT for postoperative surveillance of pathological stage I NSCLC. Further validation will be needed in the future.

Comparison between thoracic low-dose computed tomography and conventional-dose computed tomography in evaluating anemia: A preliminary study in a Chinese screening cohort.

To investigate and evaluate the value of thoracic low dose computed tomography (LDCT) scan in the diagnosis of anemia. 661 patients who received thoracic computed tomography (CT) examination and underwent a peripheral blood examination were retrospectively included. 341 patients underwent conventional dose CT (CDCT), and 320 patients underwent LDCT. Regions of interest (ROI) were placed on the left ventricular cavity (LV), descending aorta (DAo), and interventricular septum (IVS). The corresponding CT attenuation was measured, and the CT attenuation difference between LV and IVS (IVS-LV) and between DAo and IVS (IVS-DAo) was calculated, respectively. One-way analysis of variance (ANOVA) and linear regression were performed to analyze the relationship between these indicators and Hb levels. The receiver operating characteristic (ROC) curve was used to evaluate prediction performance. Both attenuation on LDCT and CDCT showed significant differences between the healthy group and the anemic group (P < 0.05). In the LDCT group, the LV and DAo were more relevant with the hemoglobin (Hb) level (correlation coefficient 0.618 and 0.602) than other indicators, with AUCs of 0.815 (95% CI: 0.763-0.868) and 0.803 (95% CI: 0.747-0.859), respectively. The linear regression formulas for Hb level with the LV and DAo were 19.14 + 0.15 × HU [95% CI: (16.52, 21.75) + (0.12, 0.17) × HU] and 19.46 + 0.16 × HU [95% CI: (16.55, 22.36) + (0.13, 0.18) × HU], respectively. Youden's index indicated that 37.5 HU and 38.5 HU were the best thresholds to diagnose anemia for LV and DAo, respectively. In the CDCT group, the LV and IVS-LV got obviously higher correlation coefficients (0.813 and 0.812), with AUCs of 0.831 (95% CI: 0.786-0.877) and 0.851 (95% CI: 0.808-0.894), respectively. The optimal thresholds for LV and IVS-LV were 40.5 HU and 9.5 HU, respectively. In LDCT examinations, an approximation of Hb level and detecting of anemia can be conducted based on simple attenuation measurements.

Impact of low-dose computed tomography (LDCT) screening on lung cancer-related mortality.

Impact of low-dose computed tomography (LDCT) screening on lung cancer-related mortality.

Unenhanced abdominal low-dose CT reconstructed with deep learning-based image reconstruction: image quality and anatomical structure depiction

PurposeTo evaluate the utility of deep learning-based image reconstruction (DLIR) algorithm in unenhanced abdominal low-dose CT (LDCT).Materials and methodsTwo patient groups were included in this prospective study: 58 consecutive patients who underwent unenhanced abdominal standard-dose CT reconstructed with hybrid iterative reconstruction (SDCT group) and 48 consecutive patients who underwent unenhanced abdominal LDCT reconstructed with high strength level of DLIR (LDCT group). The background noise and signal-to-noise ratio (SNR) of the liver, pancreas, spleen, kidney, abdominal aorta, inferior vena cava, and portal vein were calculated. Two radiologists qualitatively assessed the overall image noise, overall image quality, and abdominal anatomical structures depiction. Quantitative and qualitative parameters and size-specific dose estimates (SSDE) were compared between SDCT and LDCT groups.ResultsThe background noise was lower in LDCT group than in SDCT group (P = 0.02). SNRs were higher in LDCT group than in SDCT group (P < 0.001–0.004) except for the liver. Overall image noise was superior in LDCT group than in SDCT group (P < 0.001). Overall image quality was not different between SDCT and LDCT groups (P = 0.25–0.26). Depiction of almost all abdominal anatomical structures was equal to or better in LDCT group than in SDCT group (P < 0.001–0.88). The SSDE was lower in LDCT group (4.0 mGy) than in SDCT group (20.6 mGy) (P < 0.001).ConclusionsDLIR facilitates substantial radiation dose reduction of > 75% and significantly reduces background noise. DLIR can maintain image quality and anatomical structure depiction in unenhanced abdominal LDCT.

Incidence of Head and Neck Cancer With Lung Cancer Screening: Secondary Analysis of a Randomized Controlled Trial.

To evaluate the incidence of head and neck cancers (HNC) in high-risk current and/or former smokers with screening low-dose computed tomography (LDCT) chest versus chest x-ray (CXR). Second analysis of randomized clinical trial. We performed a secondary analysis examining the incidence of HNC in the National Lung Screening Trial. This was a randomized trial comparing LDCT versus CXR screening for lung cancer detection in high-risk individuals (30 pack-year smokers who currently smoke or quit within the last 15 years, aged 55-74). We compared the incidence of HNC in participants screened with LDCT versus CXR. We performed subgroup analyses in participants with mucosal HNC (oral cavity, oropharynx, larynx, hypopharynx, nasal/sinus cavity, or nasopharynx) or nonmucosal HNC (thyroid or salivary gland) and examined survival in the two screening arms. This trial enrolled 53,452 participants with a median follow-up of 6.2 years after randomization. The incidence of HNC was 111.8 cases per 100,000 person-years in the LDCT group versus 87.1 cases per 100,000 person-years in the CXR group (rate ratio 1.30, 95% confidence interval [CI] 1.05-1.61). There were 11.7 deaths from HNC per 100,000 person-years in the LDCT group and 12.9 deaths per 100,000 person-years in the CXR group (hazard ratio 0.80, 95% CI 0.42-1.52). Participants screened with LDCT had a modestly higher incidence of HNC. As uptake and adherence of lung cancer screening guidelines improve, clinicians should recognize that incidental findings from screening may lead to increased detection of HNC. 3 Laryngoscope, 132:1609-1614, 2022.

Incidence of Second Primary Lung Cancer After Low-Dose Computed Tomography vs Chest Radiography Screening in Survivors of Head and Neck Cancer

In head and neck cancer survivors, lung cancer screening may aid in detecting a second primary lung cancer or metastatic head and neck cancer earlier in the course of disease, which may improve treatment outcomes. However, no randomized data exist to assess the value of lung cancer screening in this population. To evaluate the incidence of second primary lung cancer in survivors of head and neck cancer survivors with screening low-dose computed tomography (CT) vs chest radiography (CXR). For this ad hoc secondary analysis of a randomized clinical trial, head and neck cancer survivors were identified from the National Lung Screening Trial, which enrolled participants from August 2002 to April 2004. This randomized clinical trial compared screening using low-dose CT chest vs CXR in patients aged 55 to 74 years with at least a 30 pack-year history of cigarette smoking and who were current smokers or had quit within the past 15 years and who were at high risk for lung cancer. The incidences of second primary lung cancer and second primary head and neck cancer were compared with screening using low-dose CT vs CXR. Data were analyzed from December 1, 2020, to June 30, 2021. Screening low-dose CT of the chest vs CXR. The primary outcome was the incidence of a second primary lung cancer. Among 53 452 enrolled participants, we identified 171 survivors of head and neck cancer, of whom 82 were screened with low-dose CT of the chest and 89 with CXR. Participants' mean (SD) age was 61 (5) years, and 132 were men (77.2%). The incidence of lung cancer was higher among head and neck cancer survivors compared with participants without head and neck cancer (2080 per 100 000 person-years [2.1%] vs 609 per 100 000 person-years [0.6%]; adjusted rate ratio, 2.54; 95% CI, 1.63-3.95). In head and neck cancer survivors, the incidence of second primary lung cancer was 2610 cases per 100 000 person-years in the low-dose CT group vs 1594 cases per 100 000 person-years in the CXR group (rate ratio, 1.55; 95% CI, 0.59-3.63). In head and neck cancer survivors, overall survival was 7.07 years with low-dose CT vs 6.66 years with CXR (log-rank P = .48). The results of this ad hoc secondary analysis of a randomized clinical trial suggest that head and neck cancer survivors are at especially high risk for a second primary lung cancer. These findings underscore the importance of low-dose CT screening in head and neck cancer survivors with significant cigarette smoking history who are fit to undergo treatment with curative intent.

Recent Survey of Effective Doses of F-18 FDG Torso PET/CT in Korea and the Current Recommendations for CT Protocols of PET/CT.

This study aimed to construct a database of the effective doses (ED) from F-18 fluorodeoxyglucose (FDG) torso positron emission tomography/computed tomography (PET/CT) in Korea to provide data that supports the reduction of the CT dose of PET/CT and optimization of PET/CT protocols in Korea. We investigated data of ED and CT parameters of FDG PET/CT. The data were analyzed by body weight groups. A total of 31 hospitals participated in the survey (99 adults). The mean total EDs (± SD) were 8.77 ± 2.76, 10.93 ± 3.14, and 12.57 ± 3.79mSv for the 55-, 70-, and 85-kg groups, respectively. The FDG EDs were 4.80 ± 0.98, 6.05 ± 1.15, and 6.89 ± 1.52mSv, and the CT EDs were 4.00 ± 2.12, 4.88 ± 2.51, and 5.68 ± 2.89mSv, respectively. Of the enrolled hospitals, 54.5% used ultra-low-dose CT protocols, and their CT ED was significantly lower than low-dose CT group in all groups (2.9 ± 1.0, 3.2 ± 1.1, and 3.3 ± 1.0mSv vs. 6.6 ± 1.6, 7.2 ± 2.1, and 7.9 ± 2.2mSv, all p < 0.001, respectively). In the ultra-low-dose CT group, the CT ED with the iterative reconstruction was significantly lower than that of CT without iterative reconstruction in the 55-kg group (2.4 ± 0.9 vs. 3.3 ± 0.9, p = 0.04). These results and current recommendations can be helpful for optimizing PET/CT diagnostic reference level (DRL) and reducing unnecessary PET/CT radiation exposure.

Low-Dose Computed Tomography Reduces Radiation Exposure by 90% Compared With Traditional Computed Tomography Among Patients Undergoing Hip-Preservation Surgery

To compare the delivered radiation dose between a low-dose hip computed tomography (CT) scan protocol and traditional hip CT scan protocols (i.e., "traditional CT"). This was a retrospective comparative cohort study. Patients who underwent hip-preservation surgery (including arthroscopy, surgical hip dislocation, or periacetabular osteotomy procedures) at our institution between 2016 and 2017 were identified. Patients were excluded if they had a body mass index (BMI) greater than 35, they underwent previous surgery, or a radiation dose report was absent. The low-dose group included patients who underwent hip CT at our institution using a standardized protocol of 100kV (peak), 100 milliampere-seconds (mAs), and a limited scanning field. The traditional CT group included patients who had hip CT scans performed at outside institutions. The total effective dose (Ehip), effective dose per millimeter of body length scanned, patients' age, and patients' BMI were compared by univariate analysis. The correlation of Ehip to BMI was assessed. The study included 41 consecutive patients in the low-dose group and 18 consecutive patients in the traditional CT group. Low-dose CT resulted in a 90% reduction in radiation exposure compared with traditional CT (Ehip, 0.97 ± 0.28mSv vs 9.68 ± 6.67mSv; P < .0001). Age (28 ± 11years vs 26 ± 10years, P= .42), sex (83% female patients vs 76% female patients, P= .74), and BMI (24 ± 3 vs 24 ± 3, P= .75) were not different between the 2 groups. Ehip had a poor but significant correlation to BMI in the low-dose CT group (R2= 0.14, slope= 0.03, P= .02) and did not correlate to BMI in the traditional CT group (R2= 0.13, P= .14). A low-dose hip CT protocol for the purpose of hip-preservation surgical planning resulted in a 90% reduction in radiation exposure compared with traditional CT. Level II, diagnostic study.

Ultrasound-guided versus low dose computed tomography scanning guidance for lumbar facet joint injections: same accuracy and efficiency

BackgroundThe purpose of this study was to investigate the feasibility, accuracy and efficiency of the facet joint injections in the lumbar spine by ultrasound guided versus lose dose computed tomography (CT) guidance.MethodsFirst the examination on the joint space of the facet joints of the lumbar spine was obtained by the ultrasound in 10 patients. Second forty patients were randomized assigned into two groups: ultrasound group and low dose CT group. Comparison was made in the clinical efficiency between the ultrasound-guided group and CT group. The feasibility, accuracy and efficiency of the ultrasound-guided lumbar facet joint injections were also evaluated.ResultsA total of 88 lumbar facet joints from L1 to S1 were clearly visualized in the 10 patients. Both the ultrasound and the CT measurements showed the same average depth and lateral distance to the reference point (P > 0.05). And 86.5% of the facet joint injections (64/74) were correctly performed under the ultrasound guidance in the first time. The exact placement of the needle tips was evaluated by CT. After the lumbar facet joint injections, the clinical efficiency was almost the same in the ultrasound-guided group as in the CT group.ConclusionsThe lumbar facet joint space can be accurately demonstrated by ultrasound. The ultrasound-guided facet joint injection in the lumbar spine obtained almost the same satisfactory feasibility, accuracy and clinical efficiency compared with low dose CT. Ultrasound technique could provide the real-time monitoring.Trial registrationThis study was registered on Chinese Clinical Trial Registry (ChiCTR1800018819, retrospective registered on 11/10/2018).

Diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings: a systematic review and meta-analysis.

To assess the diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings and the proportion of acute appendicitis on final diagnosis among equivocal CT findings. MEDLINE and EMBASE databases were searched until October 21, 2017, for studies investigating diagnostic performance of CT for acute appendicitis in pediatric patients confirmed by histopathologic findings and/or clinical follow-up. Pooled estimates of sensitivity and specificity were calculated using a hierarchical logistic regression modeling. The proportion of true appendicitis among patients with inconclusive CT results was obtained using fixed and random effects meta-analyses. Twenty-two articles with 3396 patients were included. The pooled sensitivity and specificity were 95% (95% CI, 93-97%) and 94% (95% CI, 90-96%), respectively, and the area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.98 (95% CI, 0.96-0.99). Subgroup analyses revealed a comparable diagnostic performance in the low-dose CT group (sensitivity, 97%; specificity, 96%) and the unenhanced group (sensitivity, 95%; specificity, 95%). Other subgroups (publication year, study design, enrolled population, true appendicitis proportion, CT channel number, and slice thickness) also showed good diagnostic performance. Six studies reporting the true appendicitis proportion among patients with equivocal CT findings had pooled proportion of 17% (95% CI, 9-29%). CT showed good performance for suspected appendicitis in pediatric patients under various clinical settings, including in cases with dose reduction or absence of IV contrast. The prevalence of true appendicitis among patients with equivocal appendicitis results on CTs was not low; therefore, clinical attention should not be disregarded in this population.

Community-based lung cancer screening with low-dose CT in China: Results of the baseline screening

ObjectivesTo investigate whether low-dose computed tomography (LDCT) screening is capable of enhancing the detection rate of early-stage lung cancer in high-risk population of China with both smoking and non-smoking related factors. MethodsFrom 2013–2014, eligible participants with high-risk factors of lung cancer were randomly assigned to a screening group or a control group with questionnaire inquiries. Any non-calcified nodules or masses with longest diameters of ≥4 mm identified on LDCT images were considered as positive. ResultsA total of 6717 eligible participants were randomly enrolled to a study group (3550 to LDCT screening and 3167 to standard care). 3512 participants (98.9%) underwent LDCT screening, and 3145 participants (99.3%) received questionnaire inquiries. A positive screening result was observed in 804 participants (22.9%). In the two-year follow-up period, lung cancer was detected in 51 participants (1.5%) in the LDCT group versus 10 (0.3%) in the control group (stage I: 48 vs 2; stage II to IV or limited stage: 3 vs 8), respectively. Early-stage lung cancer was found in 94.1% vs 20%, respectively. ConclusionsCompared to usual care, LDCT led to a 74.1% increase in detecting early-stage lung cancer. This study provides insights about the non-smoking related risk factors of lung cancer in the Chinese population.

MA 14.07 Randomized Lung Cancer Screening with Low-Dose CT in China: A Specific Risk-Based Screening for Chinese Population

The purpose of the present study was to investigate whether low-dose computed tomography (LDCT) screening is capable of enhancing the detection rate of early-stage lung cancer and reducing lung cancer mortality rate in China, thus determining the appropriate duration of screening and identifying additional risk factors for lung cancers in Chinese population. A randomized lung cancer screening study was performed with participants aged 45 to 70 years old who had at least one high-risk factor as follows: 1) a history of cigarette smoking ≥20 pack-years; former smokers who had quit within the past 15 years; 2) cancer history in immediate family members; 3) personal cancer history; 4) professional exposure to carcinogens (asbestos, dust or radiation); 5) long history of passive smoking; or 6) long-term exposure to cooking oil fumes. Participants were randomly assigned to a screening group with alternating years of LDCT screening (R1, R2) or a control group with biennial questionnaire inquiries. A total of 6657 eligible participants were enrolled, 3145 participants were assigned to the control group and 3512 were assigned to the baseline LDCT screening (R1) group. 1516 participants (43.2%) underwent the second round of LDCT screening (R2) in the alternate year. At R1 and R2 rounds, 19.6% and 24.0% participants showed non-calcified nodules ≥4 mm on LDCT images. Among these, lung cancer was diagnosed in 44 participants (1.3%) at R1, 12 (0.8%) at R2, and 10 (0.3%) in the control group through either biopsy or cytologic analysis. The proportions of early-stage (0 to I) lung cancer were 97.7% at R1, 91.7% at R2 and 20% in the control group, respectively. At R1, the sensitivity of LDCT for lung cancer screening was 97.7%, the specificity was 76.8%, the positive predictive value was 5.1%, and the negative predictive value (NPV) was 99.9%; at R2, both the sensitivity and the negative predictive value increased to 100%. Two cases of lung cancer-specific deaths occurred in the control group, but no death occurred in the LDCT group. Compared to usual care, the two biennial screenings with LDCT led to a 77.7% increase at R1 and 71.7% at R2 in detecting early-stage lung cancer and a 20% decrease in lung cancer mortality. Biennial screening may be at least as efficient as annual screening in terms of detecting rate, sensitivity and NPV. This study provides insights about the non-smoking related risk factors of lung cancer in the Chinese population.

Low-dose CT for the diagnosis of appendicitis in adolescents and young adults (LOCAT): a pragmatic, multicentre, randomised controlled non-inferiority trial

CT radiation is arguably carcinogenic. Results from single-centre studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, adoption of low-dose CT has been slow. We aimed to assess the effectiveness of low-dose CT compared with standard-dose CT in the diagnosis of appendicitis in adolescents and young adults. We did this pragmatic, multicentre, randomised controlled non-inferiority trial at 20 South Korean teaching hospitals with little experience with low-dose CT. Patients aged 15-44 years with suspected appendicitis were randomly assigned (1:1), via computer-generated random assignments (permuted block sizes of two, four, six, and eight) concealed in sequentially numbered envelopes, to receive low-dose CT (2 mSv) or standard-dose CT (≤8 mSv). Randomisation was stratified by site. Group allocation was concealed from patients, outcome assessors, and adverse event adjudicators; care providers, site pathologists, and data collectors were aware of allocation. The primary endpoint was the negative (unnecessary) appendectomy rate among all appendectomies, with a non-interiority margin of 4·5% for low-dose versus standard-dose CT. Primary analysis was by modified intention to treat, which included all patients who received an appendectomy in the group to which they were assigned. This trial is registered with ClinicalTrials.gov, number NCT01925014. Between Dec 4, 2013, and Aug 18, 2016, we assigned 1535 patients to the low-dose CT group and 1539 patients to the standard-dose CT group. 22 (3·9%) of 559 patients had a negative appendectomy in the low-dose group versus 16 (2·7%) of 601 patients in the standard-dose group (difference 1·3%, 95% CI -0·8 to 3·3; p=0·0022 for the non-inferiority test). We recorded 43 adverse events in 43 (2·8%) of 1535 patients in the low-dose group and 41 adverse events in 40 (2·6%) of 1539 patients in the standard-dose group. One life-threatening adverse event of anaphylaxis caused by an iodinated contrast material occurred in the low-dose group. Radiation dose of appendiceal CT for adolescents and young adults can be reduced to 2 mSv without impairing clinical outcomes. In view of the vast number of appendiceal CT examinations done worldwide, use of low-dose CT could prevent a sizeable number of radiation-associated cancers in the future. Korea Health Industry Development Institute, Seoul National University Bundang Hospital, Dasol Life Science, and Bracco Imaging Korea.

Progress in preoperative localization for small pulmonary nodules

Video-assisted thoracic surgery (VATS) is associated with reduced postoperative pain, shorter hospital stay, and fewer perioperative complications than thoracotomy, and its application in surgery for both primary lung cancer and metastatic lung tumors is increasing. Lung cancer screening with annual low-dose computed tomography (CT) has reduced morality from lung cancer, as compared with chest radiography (1), while 24.2% of screened cases were positive in the low-dose CT group. The current guidelines recommend surgical biopsy if a lung nodule is ≥8 mm in size and the probability of malignancy is high (2). Furthermore, VATS wedge resection is recommended to obtain diagnosis for an indeterminate nodule. The increased use of CT screening for lung cancer will increase the number of cases where VATS is necessary for small pulmonary nodules.

The usefulness of low-dose CT scan in elderly patients with suspected acute lower respiratory infection in the emergency room.

To evaluate the usefulness of low-dose CT (LDCT) for the diagnosis of acute lower respiratory infection (ALRI) in elderly patients in the emergency room (ER). A total of 160 consecutive patients (mean age: 75.9 ± 9.2 years; range: 60-97 years), who were diagnosed to have ALRI by LDCT in the ER, were enrolled in this study. Initial chest radiograph (CR) and CT patterns of ALRI were analysed, and clinical courses of patients were assessed. 49 patients showed negative CR, in whom the main CT patterns were diffuse bronchial wall thickening (n = 23), ground-glass opacity (n = 6), mixed centrilobular nodules and ground-glass opacity (n = 3), small consolidation (n = 8) or consolidation in the dependent lung (n = 9), while the other 111 patients with the main CT pattern of consolidation demonstrated pulmonary abnormality on CR. Pulmonary oedema (12.5%) and pleural effusion (23.1%) were associated. The rate of hospitalization, care in the intensive care unit, mortality and comorbidity were significantly higher in the CR(+)LDCT(+) group (88.3%, 36.1%, 18.2% and 59.5%) than in the CR(-)LDCT(+) group (55.1%, 8.2%, 2.0% and 38.8%; p ≤ 0.05). LDCT was useful for the early diagnosis of ALRI in elderly patients who showed negative initial CR. The patients with negative initial CR had main CT patterns of diffuse bronchial wall thickening, ground-glass opacity, centrilobular nodules, small consolidation or consolidation in the dependent lung on LDCT. The use of LDCT may be considered for the early diagnosis of ALRI in elderly patients who have high comorbidity.

Status and perspectives of detection by low-dose computed tomography or computed radiography in surgical patients with lung cancer, based on a five-year study.

A retrospective study involving 502 lung cancer patients who had received pulmonary resection from 2009-2013 was conducted in order to compare the clinical characteristics of patients whose diagnosis was detected by low-dose computed tomography (LDCT) and computed radiography (CR). Two groups were established, based on the method of detection: the LDCT group included 172 lung cancer patients; the CR group included 330 lung cancer patients. The evolution of proportions of patients in urban and rural regions was also analyzed, according to detection method. The percentage of patients with stage I was higher in the LDCT group than in the CR group (77.3%, 133/172 vs. 53.6%, 177/330). The incidence of postoperative complications within 30 days was significantly lower in the LDCT than in CR group (25.0% vs. 33.6%). The proportion of patients detected by LDCT or CR in urban regions was constantly higher than in rural regions (with an increase of 13.0% vs. 5.9%); the proportion of LDCT-detected patients in urban regions was constantly higher than in rural regions (with an increase of 8.7% vs. 5.9%). LDCT contributes to a higher proportion of early lung cancer diagnoses and a lower incidence of postoperative complications in surgical patients. The proportions of patients detected early and by LDCT have both increased steadily during the last five years. These two trends are more pronounced in urban compared with rural patients.

Performance of Lung-RADS in the National Lung Screening Trial: a retrospective assessment.

Lung cancer screening with low-dose computed tomography (LDCT) has been recommended, based primarily on the results of the NLST (National Lung Screening Trial). The American College of Radiology recently released Lung-RADS, a classification system for LDCT lung cancer screening. To retrospectively apply the Lung-RADS criteria to the NLST. Secondary analysis of a group from a randomized trial. 33 U.S. screening centers. Participants were randomly assigned to the LDCT group of the NLST, were aged 55 to 74 years, had at least a 30-pack-year history of smoking, and were current smokers or had quit within the past 15 years. 3 annual LDCT lung cancer screenings. Lung-RADS classifications for LDCT screenings. Lung-RADS categories 1 to 2 constitute negative screening results, and categories 3 to 4 constitute positive results. Of 26 722 LDCT group participants, 26 455 received a baseline screening; 48 671 screenings were done after baseline. At baseline, the false-positive result rate (1 minus the specificity rate) for Lung-RADS was 12.8% (95% CI, 12.4% to 13.2%) versus 26.6% (CI, 26.1% to 27.1%) for the NLST; after baseline, the false-positive result rate was 5.3% (CI, 5.1% to 5.5%) for Lung-RADS versus 21.8% (CI, 21.4% to 22.2%) for the NLST. Baseline sensitivity was 84.9% (CI, 80.8% to 89.0%) for Lung-RADS versus 93.5% (CI, 90.7% to 96.3%) for the NLST, and sensitivity after baseline was 78.6% (CI, 74.6% to 82.6%) for Lung-RADS versus 93.8% (CI, 91.4% to 96.1%) for the NLST. Lung-RADS criteria were applied retrospectively. Lung-RADS may substantially reduce the false-positive result rate; however, sensitivity is also decreased. The effect of using Lung-RADS criteria in clinical practice must be carefully studied. National Institutes of Health.

Overcoming perceived hurdles in lung cancer screening: the low risk of complications of image-guided transthoracic needle biopsy.

Overcoming perceived hurdles in lung cancer screening: the low risk of complications of image-guided transthoracic needle biopsy.