Diagnostic performance of CT-guided percutaneous transthoracic core needle biopsy using low tube voltage (100 kVp): comparison with conventional tube voltage (120 kVp)

Optimizing lung biopsy procedures:Comparative analysis of diagnostic efficacy and safety in experimental low-dose, conventional low-dose, and standard-dose CT-guided approaches

PURPOSE

Lung cancer is a major cause of cancer-related deaths, emphasizing the importance of early diagnosis. CT-guided percutaneous lung biopsy(CT-PLB) is a valuable method for diagnosing lung lesions, but multiple scans can elevate radiation exposure. This study aims to compare diagnostic efficacy and safety across different CT-PLB protocols.

METHODS

273 consecutive patients who underwent CT-PLB between June 2018 and February 2021 were enrolled, and were divided into standard-dose, conventional low-dose, and experimental low-dose groups. The study mainly evaluated technical success, diagnostic efficacy, radiation dose, complications, and image quality.

RESULTS

93 patients were assigned to standard-dose group, 85 to conventional low-dose group, and 95 to experimental low-dose group. Technical success rates in these groups were 97.9%, 100%, and 97.9%, respectively. Procedure-related complications rates were similar across the groups(pneumothorax:p=0.71, hemorrhage:p=0.59). Sensitivity, specificity, and overall diagnostic accuracy were comparable among three groups(p=0.59,1.0,0.65), with respective values of 90.5%, 100%, and 93.2% in standard-dose group, 88.1%, 100%, and 90.5% in conventional low-dose group, and 91.9%, 100%, and 93.4% in experimental low-dose group. The effective dose (ED) in the experimental low-dose group was significantly lower compared to both the standard-dose and conventional low-dose CT-PLB groups[ED: 1.49(1.0∼1.97) mSv vs 5.42(3.92∼6.91) mSv vs 3.15(2.52∼4.22) mSv, p<0.001].

CONCLUSIONS

This study has developed a standardized six-step procedure for CT-PLB using experimental low-dose settings. It can achieve comparable diagnostic efficacy to conventional low-dose and standard-dose CT-PLB protocols while substantially reducing radiation exposure. These findings indicate that the experimental low-dose protocol could serve as a safe and effective alternative for CT-PLB.

Implementation of Individualized Low-Dose Computed Tomography-Guided Hook Wire Localization of Pulmonary Nodules: Feasibility and Safety in the Clinical Setting

Background: CT-guided hook-wire localization is an essential step in the management of small pulmonary nodules. Few studies, however, have focused on reducing radiation exposure during the procedure. Purpose: This study aims to explore the feasibility of implementing a low-dose computed tomography (CT)-guided hook wire localization using tailored kVp based on patients' body size. Materials and Methods: A total of 151 patients with small pulmonary nodules were prospectively enrolled for CT-guided hook wire localization using individualized low-dose CT (LDCT) vs. standard-dose CT (SDCT) protocols. Radiation dose, image quality, characteristics of target nodules and procedure-related variables were compared. All variables were analyzed using Chi-Square and Student's t-test. Results: The mean CTDIvol was significantly reduced for LDCT (for BMI ≤ 21 kg/m2, 0.56 ± 0.00 mGy and for BMI > 21 kg/m2, 1.48 ± 0.00 mGy) when compared with SDCT (for BMI ≤ 21 kg/m2, 5.24 ± 0.95 mGy and for BMI > 21 kg/m2, 6.69 ± 1.47 mGy). Accordingly, the DLP of LDCT was significantly reduced as compared with that of SDCT (for BMI ≤ 21 kg/m2, 56.86 ± 4.73 vs. 533.58 ± 122.06 mGy.cm, and for BMI > 21 kg/m2, 167.02 ± 38.76 vs. 746.01 ± 230.91 mGy.cm). In comparison with SDCT, the effective dose (ED) of LDCT decreased by an average of 89.42% (for BMI ≤ 21 kg/m2) and 77.68% (for BMI > 21 kg/m2), respectively. Although the images acquired with the LDCT protocol yielded inferior quality to those acquired with the SDCT protocol, they were clinically acceptable for hook wire localization. Conclusions: LDCT-guided localization can provide safety and nodule detection performance comparable to SDCT-guided localization, benefiting radiation dose reduction dramatically, especially for patients with small body mass indexes.

Low-dose versus standard-dose computed tomography-guided biopsy for pulmonary nodules: a randomized controlled trial

BACKGROUND

To assess relative safety and diagnostic performance of low- and standard-dose computed tomography (CT)-guided biopsy for pulmonary nodules (PNs).

MATERIALS AND METHODS

This was a single-center prospective randomized controlled trial (RCT). From June 2020 to December 2020, consecutive patients with PNs were randomly assigned into low- or standard-dose groups. The primary outcome was diagnosis accuracy. The secondary outcomes included technical success, diagnostic yield, operation time, radiation dose, and biopsy-related complications. This RCT was registered on 3 January 2020 and listed within ClinicalTrials.gov (NCT04217655).

RESULTS

Two hundred patients were randomly assigned to low-dose (n = 100) and standard-dose (n = 100) groups. All patients achieved the technical success of CT-guided biopsy and definite final diagnoses. No significant difference was found in operation time (n = 0.231) between the two groups. The mean dose-length product was markedly reduced within the low-dose group compared to the standard-dose group (31.5 vs. 333.5 mGy-cm, P < 0.001). The diagnostic yield, sensitivity, specificity, and accuracy of the low-dose group were 68%, 91.5%, 100%, and 94%, respectively. The diagnostic yield, sensitivity, specificity, and accuracy were 65%, 88.6%, 100%, and 92% in the standard-dose group. There was no significant difference observed in diagnostic yield (P = 0.653), diagnostic accuracy (P = 0.579), rates of pneumothorax (P = 0.836), and lung hemorrhage (P = 0.744) between the two groups.

CONCLUSIONS

Compared with standard-dose CT-guided biopsy for PNs, low-dose CT can significantly reduce the radiation dose, while yielding comparable safety and diagnostic accuracy.

Low-dose CT with tin filter combined with iterative metal artefact reduction for guiding lung biopsy

Background

Computed tomography (CT) is currently the imaging modality of choice for guiding pulmonary percutaneous procedures. The use of a tin filter allows low-energy photons to be absorbed which contribute little to image quality but increases the radiation dose that a patient receives. Iterative metal artefact reduction (iMAR) was developed to diminish metal artefacts. This study investigated the impact of using tin filtration combined with an iMAR algorithm on dose reduction and image quality in CT-guided lung biopsy.

Methods

Ninety-nine consecutive patients undergoing CT-guided lung biopsy were randomly assigned to routine-dose CT protocols (groups A and B; without and with iMAR, respectively) or tin filter CT protocols (groups C and D; without or with iMAR, respectively). Subjective image quality was analysed using a 5-point Likert scale. Objective image quality was assessed, and the noise, contrast-to-noise ratio, and figure of merit were compared among the four groups. Metal artefacts were quantified using CT number reduction and metal diameter blurring. The radiation doses, diagnostic performance, and complication rates were also estimated.

Results

The subjective image quality of the two scan types was compared. Images with iMAR reconstruction were superior to those without iMAR reconstruction (group A: 3.49±0.65 vs. group B: 4.63±0.57; P<0.001, and group C: 3.88±0.66 vs. group D: 4.82±0.39; P<0.001). Images taken with a tin filter were found to have a significantly higher figure-of-merit than those taken without a tin filter (group A: 14,041±7,230 vs. group C: 21,866±10,656; P=0.001, and group B: 13,836±6,849 vs. group D: 21,639±9,964; P=0.001). In terms of metal artefact reduction, tin filtration combined with iMAR showed the lowest CT number reduction (116.62±103.48 HU) and metal diameter blurring (0.85±0.30) among the protocols. The effective radiation dose in the tin filter groups was 73.2% lower than that in the routine-dose groups. The complication rate and diagnostic performance (sensitivity, specificity, and overall accuracy) did not differ significantly between the tin filter and routine-dose groups (all P>0.05).

Conclusions

Tin filtration combined with an iMAR algorithm may reduce the radiation dose compared to the routine-dose CT protocol, while maintaining comparable diagnostic accuracy and image quality and producing fewer metal artefacts.

Value of low-dose and optimized-length computed tomography (CT) scan in CT-guided percutaneous transthoracic needle biopsy of pulmonary nodules

Objective

To investigate the value of application of low-dose and optimized length CT scan on puncture results, complications and patients’ radiation dosage during CT-guided percutaneous biopsy of pulmonary nodules (PTNB).

Methods

A total of 231 patients with PTNB under CT guidance were collected. Low dose scanning utilized tube current of 20 mA as compared with 40 mA in conventional dosage. Optimized length in CT is defined as intentionally narrowing the range of CT scanning just to cover 25 mm (5 layers) around the target layer during needle adjustment. According to whether low-dose scans and optimized length scans techniques were utilized, patients were divided into three groups: conventional group (conventional sequence + no optimization), optimized length group (conventional sequence + optimized length), and low-dose optimized length group (low dose sequence + optimized length). The ED (effective dose), the DLP (dose length product), the average CTDIvol (Volume CT dose index), total milliampere second between subgroups were compared.

Results

Compared with the conventional group, ED, intraoperative guidance DLP, total milliseconds and operation time in the optimized length group were reduced by 18.2% (P=0.01), 37% (P=0.003), 17.5% (P=0.013) and 13.3% (P=0.021) respectively. Compared with the optimized length group, the ED was reduced by 87%, preoperative positioning, intraoperative guidance and postoperative review DLP were also reduced by 88%, total milliampere second was reduced by 79%, with an average CTDIvol was reduced by 86%, in the low-dose optimized length group (P<0.001 for all).

Conclusion

Optimizing the length during CT scanning can effectively reduce the intraoperative radiation dose and reduce the operation time compared with conventional plan; low-dose and optimized length CT scan can further reduce the total radiation dose compared with optimized length group with no differences on intraoperative complications, biopsy results and operation time.

Diagnostic accuracy and complication rate of image-guided percutaneous transthoracic needle lung biopsy for subsolid pulmonary nodules: a systematic review and meta-analysis

OBJECTIVES

To determine the diagnostic accuracy and complication rate of percutaneous transthoracic needle biopsy (PTNB) for subsolid pulmonary nodules and sources of heterogeneity among reported results.

METHODS

We searched PubMed, EMBASE, and Cochrane libraries (until November 7, 2020) for studies measuring the diagnostic accuracy of PTNB for subsolid pulmonary nodules. Pooled sensitivity and specificity of PTNB were calculated using a bivariate random-effects model. Bivariate meta-regression analyses were performed to identify sources of heterogeneity. Pooled overall and major complication rates were calculated.

RESULTS

We included 744 biopsies from 685 patients (12 studies). The pooled sensitivity and specificity of PTNB for subsolid nodules were 90% (95% confidence interval [CI]: 85-94%) and 99% (95% CI: 92-100%), respectively. Mean age above 65 years was the only covariate significantly associated with higher sensitivity (93% vs  85%, p = 0.04). Core needle biopsy showed marginally higher sensitivity than fine-needle aspiration (93% vs  83%, p = 0.07). Pooled overall and major complication rate of PTNB were 43% (95% CI: 25-62%) and 0.1% (95% CI: 0-0.4%), respectively. Major complication rate was not different between fine-needle aspiration and core needle biopsy groups (p = 0.25).

CONCLUSION

PTNB had acceptable performance and a low major complication rate in diagnosing subsolid pulmonary nodules. The only significant source of heterogeneity in reported sensitivities was a mean age above 65 years.

ADVANCES IN KNOWLEDGE

This is the first meta-analysis attempting to systemically determine the cause of heterogeneity in the diagnostic accuracy and complication rate of PTNB for subsolid pulmonary nodules.

Learning Curve for CT-Guided Percutaneous Transthoracic Core Needle Biopsy: Retrospective Evaluation Among 17 Thoracic Imaging Fellows at a Tertiary Referral Hospital

To listen to the podcast associated with this article, please select one of the following: iTunes, Google Play, or direct download. Background: CT-guided percutaneous transthoracic needle biopsy (PTNB) is widely used for evaluation of indeterminate pulmonary lesions, though guidelines are lacking regarding the experience needed to gain sufficient skill. Objective: To investigate the learning curve among a large number of operators in a tertiary referral hospital and to determine the number of procedures required to obtain acceptable performance. Methods: This retrospective study included CT-guided PTNBs with coaxial technique performed by 17 thoracic imaging fellows from March 2011 to August 2017 who were novices in the procedure. A maximum of 200 consecutive procedures per operator were included. Cumulative summation method was used to assess learning curves for diagnostic accuracy, false negative rate, pneumothorax rate, and hemoptysis rate. Operators were assessed individually and in a pooled analysis. Pneumothorax risk was also assessed in a model adjusting for risk factors. Acceptable failure rates were defined as 0.1 for diagnostic accuracy and false negative rate; 0.45 for pneumothorax rate; and 0.05 for hemoptysis rate. Results: The study included 3261 procedures in 3134 patients (mean age, 67.7±12.1 years; 1876 men, 1258 women). Overall diagnostic accuracy was 94.2% (2960/3141). All 17 operators achieved acceptable diagnostic accuracy [37 procedures required in pooled analysis; median of 33 procedures (range 19-67) required]. Overall false negative rate was 7.6% (179/2370). All 17 operators achieved acceptable false negative rate [52 procedures required in pooled analysis; median of 33 procedures (range 19-95) required]. Pneumothorax occurred in 32.6% (1063/3261), and hemoptysis in 2.7% (89/3261). All 17 operators achieved acceptable pneumothorax rate [20 procedures required in pooled analysis; median of 19 procedures (range 7-63) required]. In the risk-adjusted model, 15 operators achieved acceptable pneumothorax rate [54 procedures required in pooled analysis; median of 36 procedures (range 10-192) required]. Sixteen operators achieved acceptable hemoptysis rate [67 procedures required in pooled analysis; median of 55 procedures (range 41-152) required]. Conclusion: For CT-guided PTNB, at least 37 and 52 procedures are required to achieve acceptable diagnostic accuracy and false negative rate, respectively. Not all operators achieved acceptable complication rates. Clinical Impact: The findings may help set standards for training, supervision, and ongoing assessment of proficiency for this procedure.

Computed tomography-guided core needle biopsy for lung nodules: low-dose versus standard-dose protocols

Introduction

Computed tomography (CT)-guided core needle biopsy (CNB) is an essential step in the management of lung nodules (LNs). Low-dose CT (LDCT)-guided CNB has been used to decrease the radiation exposure.

Aim

To evaluate the technical success, safety, diagnostic capacity, and radiation exposure to patients between LDCT-guided and standard-dose CT (SDCT)-guided CNB for LNs.

Material and methods

This is a retrospective, single-centre study. Patients who underwent LDCT-guided or SDCT-guided CNB for LNs from January 2015 to December 2017 were included. Data on technical success, diagnostic performance, complications, and radiation exposure were collected and analysed.

Results

A total of 70 and 65 patients underwent LDCT-guided and SDCT-guided CNB procedure, respectively. The technical success rates were 100% in both groups. The diagnostic yield, sensitivity, specificity, and overall diagnostic accuracy in the LDCT and SDCT groups were 71.4% and 67.7% (p = 0.637), 97.8% and 93.2% (p = 0.625), 100%, and 100%, and 98.6% and 95.4% (p = 0.560), respectively. The independent risk factor of diagnostic failure was less sample tissues (p = 0.012; 95% confidence interval: 0.033–0.651). Pneumothorax was found in 9 and 12 patients in the LDCT and SDCT groups, respectively (p = 0.369). Lung haemorrhage was found in 11 and 12 patients in the LDCT and SDCT groups, respectively (p = 0.671). The mean dose-length product was 38.3 ±17.0 mGy · cm and 376.0 ±118.7 mGy · cm in the LDCT and SDCT groups, respectively (p < 0.001).

Conclusions

Compared to SDCT, LDCT-guided CNB can provide comparable safety and diagnostic performance for LNs while reducing exposure to radiation.

Safety and utility of performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy

This study aimed to evaluate the feasibility, safety and usefulness of performing computed tomography (CT)-guided biopsies of pulmonary lesions that arise after radiotherapy. Seventeen patients (14 males and 3 females; median age: 69 years, range: 48-84 years) underwent CT-guided biopsies of pulmonary lesions that occurred in lung regions that had previously been treated with radiotherapy. Three patients underwent CT-guided biopsies twice, and thus, the total number of procedures was 20. We reviewed the subjects' medical records and images, and evaluated the rate for obtaining pathological diagnosis with the biopsy sample, subsequent clinical course, and complications associated with the procedure. In 19 of 20 procedures (95%), the CT-guided biopsy resulted in a pathological diagnosis being obtained. In 14 procedures, the pathological results were consistent with the patients' clinical courses. In the remaining 5 procedures, the lesions were pathologically diagnosed as benign, but they increased in size thereafter; so the lesions were considered to be clinically malignant. The results were considered to represent sampling errors. There were 3 minor complications (slight pneumothorax which did not require drainage) (3/20, 15%), and there were no major complications. In conclusion, performing CT-guided biopsies of pulmonary lesions that arise after radiotherapy appears to be feasible, safe and useful.

Computed tomography-guided cutting needle biopsy for lung nodules: A comparative study between low-dose and standard dose protocols

We aim to compare the diagnostic accuracy, safety, and radiation exposure between low-dose and standard-dose computed tomography (CT)-guided cutting needle biopsy (CNB) for lung nodules.From January 2016 to August 2017, all consecutive patients admitted with lung nodule underwent low-dose or standard-dose CT-guided CNB procedure in our center. Diagnostic accuracy and radiation dose were compared.A total of 67 and 69 patients who underwent low-dose and standard-dose CT-guided CNB procedure were included in this study. Each patient underwent CT-guided CNB for 1 nodule. The technical success rates were 100% in both groups. The sensitivity, specificity, and overall diagnostic accuracy were 97.7%, 100%, and 98.5% for low-dose group and 91.5%, 100%, and 94.2% for standard-dose group. There was no significant difference in diagnostic accuracy (P = .380) between 2 groups. Pneumothorax was found in 8 and 15 patients in the low-dose and standard-dose groups, respectively (11.9% vs 21.7%, P = .127). Hemoptysis was found in 10 and 10 patients in the low-dose and standard-dose groups, respectively (14.9% vs 14.5%, P = .943). The mean dose-length product was 38.2 ± 17.2 mGy-cm and 375.3 ± 115.7 mGy-cm in the low-dose and standard-dose groups (P < .001). The mean dose-length product was 38.2 ± 17.2 mGy-cm and 375.3 ± 115.7 mGy-cm in the low-dose and standard-dose groups, respectively (P < .001). The mean effective dose was 0.5 ± 0.2 mSv and 5.3 ± 1.6 mSv in the low-dose and standard-dose groups, respectively (P < .001).Low-dose CT-guided CNB of lung nodules significantly decreased radiation dose compared with standard-dose CT. The low-dose protocol could provide similar diagnostic accuracy and safety as standard-dose CT-guided CNB for lung nodules.

2020 Clinical Practice Guideline for Percutaneous Transthoracic Needle Biopsy of Pulmonary Lesions: A Consensus Statement and Recommendations of the Korean Society of Thoracic Radiology

Percutaneous transthoracic needle biopsy (PTNB) is one of the essential diagnostic procedures for pulmonary lesions. Its role is increasing in the era of CT screening for lung cancer and precision medicine. The Korean Society of Thoracic Radiology developed the first evidence-based clinical guideline for PTNB in Korea by adapting pre-existing guidelines. The guideline provides 39 recommendations for the following four main domains of 12 key questions: the indications for PTNB, pre-procedural evaluation, procedural technique of PTNB and its accuracy, and management of post-biopsy complications. We hope that these recommendations can improve the diagnostic accuracy and safety of PTNB in clinical practice and promote standardization of the procedure nationwide.

Incidence, severity and tolerability of pneumothorax following low-dose CT-guided lung biopsy in different severities of COPD

BACKGROUND

The feasibility of pneumothorax following low-dose CT-guided puncture lung biopsy in different severities of COPD has not been reported.

METHODS

The data of the patients with pulmonary lesion who underwent low-dose CT-guided lung biopsy by one experienced operator in our hospital from January 1st to September 30th in 2019 were retrospectively collected. They were divided into COPD group and non-COPD group. The risk factors, incidence and severity of pneumothorax with the severity of COPD and changes in MMRC score, treatment way and discharge time after pneumothorax were assessed.

RESULTS

Two hundred and nineteen patients were retrospectively enrolled in this study with 64 in the COPD group and 155 in the non-COPD group. The average age, MMRC score and the incidence of pneumothorax after biopsy were significantly higher in the COPD group (64.7 ± 1.27 years, 1.02 ± 0.13, 31.3%) than in the non-COPD group (58.8 ± 1.16 years, 0.35 ± 0.06, 17.4%, P < 0.05). The incidence of pneumothorax between I-II and III-IV in COPD did not reach the significant difference (P = 0.863). COPD was the only independent risk factor for pneumothorax after biopsy in a multivariable regression (P < 0.05). MMRC score was significantly increased at post-pneumothorax in the two groups (P < 0.001). There was no significant difference in diagnostic rate, severity of pneumothorax, the proportion of delayed pneumothorax, the changes in treatment way and discharge time between the two groups (P > 0.05).

CONCLUSION

Although the incidence of pneumothorax after low dose CT-guided lung biopsy is increased in COPD, there was no difference in the severity of pneumothorax amongst the different severities of COPD and it is well-tolerated without increasing medical burden.

Reducing Radiation Dose and Improving Image Quality in CT Portal Venography Using 80 kV and Adaptive Statistical Iterative Reconstruction-V in Slender Patients

OBJECTIVE

To explore the feasibility of reducing radiation dose and improving image quality in CT portal venography (CTPV) using 80 kV and adaptive statistical iterative reconstruction-V(ASIR-V) in slender patients in comparison with conventional protocol using 120 kV and ASIR.

METHODS

Sixty slender patients for enhanced abdominal CT scanning were randomly divided into group A and group B. Group A used the conventional 120 kV tube voltage, 600 mgI/kg contrast dose and reconstructed with the recommended 40% ASIR. Group B used 80 kV tube voltage, 350 mgI/kg contrast dose and reconstructed with ASIR-V from 40% to 100% with 10% interval. The CT values and standard deviation (SD) values of the main portal vein, left branch, and right branch of portal vein, liver, and erector spinae at the same level were measured to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The image quality was subjectively scored by two experienced radiologists blindly using a 5-point criterion. The contrast dose, volumetric CT dose index, and dose length product were recorded in both groups and the effective dose was calculated.

RESULTS

There was no significant difference in general data between the two groups (p > 0.05), the effective dose and contrast dose in group B were reduced by 63.3% (p < 0.001) and 39.7% (p < 0.001), respectively compared with group A. With the percentage of ASIR-V increased in group B, the CT values showed no significant difference, while the SD values gradually decreased and SNR values and CNR values increased accordingly. Compared with group A, group B demonstrated similar CT values (p > 0.05), while the SD values with 80% ASIR-V to 100% ASIR-V were significantly lower than those of 40% ASIR (p < 0.001), and the SNR values and CNR values with 70% ASIR-V to 100% ASIR-V were significantly higher than those of 40% ASIR (p < 0.001). The subjective image quality scores by the two radiologists had excellent consistency (kappa value>0.75, p < 0.001), and the final subjective image quality scores and the subjective scores in each of the 5 scoring categories with 60% ASIR-V to 100% ASIR-V were all significantly higher than those of 40% ASIR, and 80% ASIR-V obtained the highest subjective score among different reconstructions.

CONCLUSION

In CTPV, the application of 80 kV and ASIR-V reconstruction in slender patients can significantly reduce radiation dose (by 63.3%) and contrast agent dose (by 39.7%). Compared with the recommended 40% ASIR using 120 kV, ASIR-V with 80% to 100% percentages can further improve image quality and with 80% ASIR-V being the best reconstruction algorithm.

ADVANCES IN KNOWLEDGE

CTPV with 80 kV and ASIR-V algorithm in slender patients can significantly reduce radiation dose and contrast agent dose as well as improve image quality, compared with the conventional 120 kV protocol using 40% ASIR.

Computed tomography-guided lung biopsy: a randomized controlled trial of low-dose versus standard-dose protocol

OBJECTIVES

To assess the relative diagnostic utility of low- and standard-dose computed tomography (CT)-guided lung biopsy.

METHODS

In this single-center, single-blind, prospective, randomized controlled trial, patients were enrolled between November 2016 and June 2017. Enrolled study participants were randomly selected to undergo either low- or standard-dose CT-guided lung biopsy. Diagnostic accuracy was the primary study endpoint, whereas technical success, radiation dose, and associated complications were secondary study endpoints.

RESULTS

In total, 280 patients underwent study enrollment and randomization, with 271 (low-dose group, 135; standard-dose group, 136) receiving the assigned interventions. Both groups had a 100% technical success rate for CT-guided lung biopsy, and complication rates were similar between groups (p > 0.05). The mean dose-length product (36.0 ± 14.1 mGy cm vs. 361.8 ± 108.0 mGy cm, p < 0.001) and effective dose (0.5 ± 0.2 mSv vs. 5.1 ± 1.5 mSv, p < 0.001) were significantly reduced in the low-dose group participants. Sensitivity, specificity, and overall diagnostic accuracy rates in the low-dose group were 91.8%, 100%, and 94.6%, respectively, whereas in the standard-dose group, the corresponding values were 89.6%, 100%, and 92.4%, respectively. These results indicated that diagnostic performance did not differ significantly between the 2 groups. Using univariate and multivariate analyses, we found larger lesion size (p = 0.038) and procedure-related pneumothorax (p = 0.033) to both be independent predictors of diagnostic failure.

CONCLUSIONS

Our results demonstrate that low-dose CT-guided lung biopsy can yield comparable diagnostic accuracy to standard-dose CT guidance, while significantly reducing the radiation dose delivered to patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02971176 KEY POINTS: • Low-dose CT-guided lung biopsy is a safe and simple method for diagnosis of lung lesions. • Low-dose CT-guided lung biopsy can yield comparable diagnostic accuracy to standard-dose CT guidance. • Low-dose CT-guided lung biopsy can achieve a 90% reduction in radiation exposure when compared with standard-dose CT guidance.

Non-Small Cell Lung Cancer with Resistance to EGFR-TKI Therapy: CT Characteristics of T790M Mutation-positive Cancer

Purpose To evaluate the clinical and CT characteristics of T790M mutation-positive non-small cell lung cancer (NSCLC) after epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) therapy failure. Materials and Methods A retrospective study of 304 patients with NSCLC who underwent rebiopsy after first-line EGFR-TKI therapy was conducted. Rebiopsy methods included CT- or fluoroscopy-guided lung biopsies (n = 105), endobronchial US- or bronchofibroscopy-guided biopsies (n = 66), pleural fluid analysis (n = 47), other solid organ biopsies (n = 43), US-guided axillary or supraclavicular lymph node biopsies (n = 31), and cerebrospinal fluid analysis (n = 12). CT findings at the initial diagnosis and rebiopsy were analyzed. Progression-free survival, the duration from the start of TKI therapy to rebiopsy, and survival were calculated. Results At rebiopsy, 144 (47.4%) patients were T790M mutation positive. The percentages of T790M mutation-positive NSCLCs were similar in 106 patients with rebiopsy of the lungs (53 [50%] of 106) and in 77 patients with rebiopsy of the primary lung lesions (36 [47%] of 77). T790M mutation positivity was associated with peripheral tumors (odds ratio [OR], 2.6; P = .01), pleural tag (OR, 5.0; P < .001), and air bronchogram (OR, 4.0; P = .006) at CT after TKI failure. The duration from the start of TKI therapy to rebiopsy was longer in T790M mutation-positive than in T790M mutation-negative patients (20.5 vs 13.6 months; P < .001). Cumulative survival from the time of rebiopsy to the last follow-up was significantly longer in patients with T790M mutation-positive lung cancers (P = .014). However, median survival time after rebiopsy was not statistically different between patients with and those without T790M mutation. Conclusion Peripheral tumor location with vascular convergence, the presence of a pleural tag, and air bronchogram of lung lesions at CT at the time of rebiopsy were significantly associated with T790M mutation in patients with non-small cell lung cancer after first-line epidermal growth factor receptor-tyrosine kinase inhibitor therapy failure. © RSNA, 2018 Online supplemental material is available for this article.