Radiation dose reduction in CT-guided spine biopsies does not reduce diagnostic yield

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.

Computed Tomography of the Spine

The introduction of the first whole-body CT scanner in 1974 marked the beginning of cross-sectional spine imaging. In the last decades, the technological advancement, increasing availability and clinical success of CT led to a rapidly growing number of CT examinations, also of the spine. After initially being primarily used for trauma evaluation, new indications continued to emerge, such as assessment of vertebral fractures or degenerative spine disease, preoperative and postoperative evaluation, or CT-guided interventions at the spine; however, improvements in patient management and clinical outcomes come along with higher radiation exposure, which increases the risk for secondary malignancies. Therefore, technical developments in CT acquisition and reconstruction must always include efforts to reduce the radiation dose. But how exactly can the dose be reduced? What amount of dose reduction can be achieved without compromising the clinical value of spinal CT examinations and what can be expected from the rising stars in CT technology: artificial intelligence and photon counting CT? In this article, we try to answer these questions by systematically reviewing dose reduction techniques with respect to the major clinical indications of spinal CT. Furthermore, we take a concise look on the dose reduction potential of future developments in CT hardware and software.

Low-dose multi-detector computed tomography for periradicular infiltrations at the cervical and lumbar spine

Periradicular infiltrations are frequently performed in daily neuroradiological routine and are often guided by multi-detector computed tomography (MDCT), thus leading to radiation exposure. The purpose of this study was to evaluate MDCT with low dose (LD) and model-based iterative reconstruction for image-guided periradicular infiltrations at the cervical and lumbosacral spine. We retrospectively analyzed 204 MDCT scans acquired for the purpose of cervical or lumbosacral periradicular interventions, which were either derived from scanning with standard dose (SD; 40 mA and 120 kVp) or LD (20–30 mA and 120 kVp) using a 128-slice MDCT scanner. The SD cases were matched to the LD cases considering sex, age, level of infiltration, presence of spinal instrumentation, and body diameter. All images were reconstructed using model-based iterative image reconstruction and were evaluated by two readers (R1 and R2) using 5- or 3-point Likert scales (score of 1 reflects the best value per category). Furthermore, noise in imaging data was quantitatively measured by the standard deviation (StDev) of muscle tissue. The dose length product (DLP) was statistically significantly lower for LD scans (6.75 ± 6.43 mGy*cm vs. 10.16 ± 7.70 mGy*cm; p < 0.01; reduction of 33.5%). Image noise was comparable between LD and SD scans (13.13 ± 3.66 HU vs. 13.37 ± 4.08 HU; p = 0.85). Overall image quality was scored as good to very good with only minimal artifacts according to both readers, and determination of the nerve root was possible in almost all patients (LD vs. SD: p > 0.05 for all items). This resulted in high confidence for intervention planning as well as periprocedural intervention guidance for both SD and LD scans. The inter-reader agreement was at least substantial (weighted Cohen’s κ ≥ 0.62), except for confidence in intervention planning for LD scans (κ = 0.49). In conclusion, considerable dose reduction for planning and performing periradicular infiltrations with MDCT using model-based iterative image reconstruction is feasible and can be performed without clinically relevant drawbacks regarding image quality or confidence for planning.

Differences in Radiation Exposure of CT-Guided Percutaneous Manual and Powered Drill Bone Biopsy

PURPOSE

Apart from the commonly applied manual needle biopsy, CT-guided percutaneous biopsies of bone lesions can be performed with battery-powered drill biopsy systems. Due to assumably different radiation doses and procedural durations, the aim of this study is to examine radiation exposure and establish local diagnostic reference levels (DRLs) of CT-guided bone biopsies of different anatomical regions.

METHODS

In this retrospective study, dose data of 187 patients who underwent CT-guided bone biopsy with a manual or powered drill biopsy system performed at one of three different multi-slice CT were analyzed. Between January 2012 and November 2019, a total of 27 femur (A), 74 ilium (B), 27 sacrum (C), 28 thoracic vertebrae (D) and 31 lumbar vertebrae (E) biopsies were included. Radiation exposure was reported for volume-weighted CT dose index (CTDI_vol) and dose-length product (DLP).

RESULTS

CTDI_vol and DLP of manual versus powered drill biopsy were (median, IQR): A: 56.9(41.4-128.5)/66.7(37.6-76.2)mGy, 410(203-683)/303(128-403)mGy·cm, B: 83.5(62.1-128.5)/59.4(46.2-79.8)mGy, 489(322-472)/400(329-695)mGy·cm, C: 97.5(71.6-149.2)/63.1(49.1-83.7)mGy, 627(496-740)/404(316-515)mGy·cm, D: 67.0(40.3-86.6)/39.7(29.9-89.0)mGy, 392(267-596)/207(166-402)mGy·cm and E: 100.1(66.5-162.6)/62.5(48.0-90.0)mGy, 521(385-619)/315(240-452)mGy·cm. Radiation exposure with powered drill was significantly lower for ilium and sacrum, while procedural duration was not increased for any anatomical location. Local DRLs could be depicted as follows (CTDI_vol/DLP): A: 91 mGy/522 mGy·cm, B: 90 mGy/530 mGy·cm, C: 116 mGy/740 mGy·cm, D: 87 mGy/578 mGy·cm and E: 115 mGy/546 mGy·cm. The diagnostic yield was 82.4% for manual and 89.4% for powered drill biopsies.

CONCLUSION

Use of powered drill bone biopsy systems for CT-guided percutaneous bone biopsies can significantly reduce the radiation burden compared to manual biopsy for specific anatomical locations such as ilium and sacrum and does not increase radiation dose or procedural duration for any of the investigated locations.

LEVEL OF EVIDENCE

Level 3.

Diagnostic yield, accuracy, and complication rate of CT-guided biopsy for spinal lesions: a systematic review and meta-analysis

BACKGROUND

CT-guided biopsy is a commonly used diagnostic procedure for spinal lesions. This meta-analysis aims to investigate its diagnostic performance and complications, as well as factors influencing outcomes.

METHODS

A systematic review of the literature was performed to identify studies reporting outcomes of CT-guided biopsies for spinal lesions. Diagnostic yield (ie, the rate of procedures resulting in a specific pathological diagnosis) and diagnostic accuracy (ie, the rate of procedures resulting in the correct diagnosis) were the primary outcomes of interest. Complications following biopsy procedures were also included.

RESULTS

Thirty-nine studies with 3917 patients undergoing 4181 procedures were included. Diagnostic yield per procedure was 91% (95% CI 88% to 94%) among 3598 procedures. The most common reason for non-diagnostic biopsies was inadequacy of sample. No difference in diagnostic yield between different locations and between lytic, sclerotic, and mixed lesions was found. Diagnostic yield did not differ between procedures using ≤13G and ≥14G needles. Diagnostic accuracy per procedure was 86% (95% CI 82% to 89%) among 3054 procedures. Diagnostic accuracy among 2426 procedures that yielded a diagnosis was 94% (95% CI 92% to 96%). Complication rate was 1% (95% CI 0.4% to 1.9%) among 3357 procedures. Transient pain and minor hematoma were the most common complications encountered.

CONCLUSION

In our meta-analysis of 39 studies reporting diagnostic performance and complications of CT-guided biopsy, we found a diagnostic yield of 91% and diagnostic accuracy of 86% with a complication rate of 1%. Diagnostic yield did not differ between different locations, between lytic, sclerotic and mixed lesions, and between wide- and thin-bore needles.

Time to Reconsider Routine Percutaneous Biopsy in Spondylodiscitis?

Percutaneous image-guided biopsy currently has a central role in the diagnostic work-up of patients with suspected spondylodiscitis. However, on the basis of recent evidence, the value of routine image-guided biopsy in this disease can be challenged. In this article, we discuss this recent evidence and also share a new diagnostic algorithm for spondylodiscitis that was recently introduced at our institution. Thus, we may move from a rather dogmatic approach in which routine image-guided biopsy is performed in any case to a more individualized use of this procedure.

Computed Tomography-Guided Vertebral Biopsy in Suspected Tuberculous Spondylodiscitis: Comparing a New Navigational Tram-Track Technique versus Conventional Method

Introduction Computed tomography (CT)-guided vertebral biopsy is always recommended for histopathological and microbiological confirmation in cases of tuberculous spondylodiscitis and for antimycobacterial drug sensitivity testing.

Aim To compare the conventional technique and a novel axis-defined tram-track technique of CT-guided vertebral biopsy in suspected tuberculous spondylodiscitis.

Materials and Methods Sixty-seven patients of clinico-radiologically suspected tuberculous spondylodiscitis referred for CT-guided vertebral biopsy were categorized into two groups: “Group A” patients (n = 32) underwent biopsy by conventional technique, and “Group B” patients (n = 35) by axis-defined tram-track technique. The time taken for procedure, radiation exposure, and any procedural complications were recorded for both the groups.

Results A statistically significant difference in procedure time and mean radiation dose was observed between the two groups: a longer procedural time was required in “Group A” (52.5 ± 3.5 minutes) as compared to “Group B” (37.3 ± 3.6 minutes) (p < 0.0001); and mean radiation dose (CTDIvol) in “Group A” and “Group B” was 8.64 ± 1.06 mGy and 5.73 ± 0.71 mGy, respectively (p < 0.0001). However, the difference in complication rate and tissue yield for successful diagnosis of the biopsies in the two groups was found to be statistically insignificant.

Conclusion Axis-defined tram-track technique was found to have a significantly shorter procedural time as well as lower radiation exposure compared to the conventional technique of vertebral biopsy in our study.

Reduction of Radiation Dose and Scanning Time While Preserving Diagnostic Yield: A Comparison of Battery-Powered and Manual Bone Biopsy Systems

BACKGROUND AND PURPOSE

There is scarcity of data on the comparative efficacy between bone biopsy drill systems across various types of bone lesions. Our aim was to investigate differences in diagnostic yield, scanning time, and radiation dose between manual and battery-powered bone biopsy systems in CT-guided biopsies of lytic, sclerotic, and infectious bone lesions.

MATERIALS AND METHODS

This was a retrospective single-center institutional review board-approved study. A total of 585 CT-guided core needle biopsies were performed at 1 institution from May 2010 to February 2019. Classification of bone lesions, location, bone biopsy system, suspected origin of primary disease, final pathologic diagnosis, diagnostic yield, presence of crush artifacts, radiation dose, and scanning times were collected. For the battery-powered system, OnControl was used. For the manual drill system, Bonopty, Osteo-site, and Laurane drill systems were used. Comparisons in lytic and sclerotic lesions and suspected discitis/osteomyelitis were made using the Fisher exact test. Subgroup analysis of the drill systems for scanning time and radiation dose was performed by 1-way ANOVA.

RESULTS

Our patient cohorts consisted of a total of 585 patients with 422 lytic, 110 sclerotic, and 53 suspected infectious lesions. The mean age was 62 ± 13 years with a male/female ratio of 305:280 for all lesions. The diagnostic yield was 85.5% (362/422) for lytic, 82.7% (91/110) for sclerotic, 50.9% (27/53) for infectious lesions, and 82.1% (480/585) for all lesions. No statistical difference was found when comparing diagnostic yields of powered drills with the manual systems for lytic, sclerotic, and infectious lesions. However, in a subgroup analysis, radiation dose and scanning time were significantly lower for powered drill compared with manual drill systems in lytic (P = .001 for both) and sclerotic lesions (P = .028 and P = .012, respectively). No significant differences were seen between the drill systems for suspected infectious lesions.

CONCLUSIONS

Our findings demonstrate that there was no statistically significant difference in diagnostic yield when comparing battery-powered and manual bone biopsy systems for CT-guided bone biopsies; however, the use of the power drill system resulted in significantly reduced scanning time and radiation dose in lytic and sclerotic lesions.

First experiences of a low-dose protocol for CT-guided musculoskeletal biopsies combining different radiation dose reduction techniques

Background

The use of computed tomography (CT) for image guidance during biopsies is a powerful approach. The method is, however, often associated with a significant level of radiation exposure to the patient and operator.

Purpose

To investigate if a low-dose protocol for CT-guided musculoskeletal (MSK) biopsies, including a combination of different radiation dose (RD) techniques, is feasible in a clinical setting.

Material and Methods

Fifty-seven patients underwent CT-guided fine-needle aspiration cytology (FNAC) utilizing the low-dose protocol (group A). A similar number of patients underwent CT-guided FNAC using the reference protocol (group B). Between-group comparisons comprised radiation dose, success rate, image quality parameters, and workflow.

Results

In group A, the mean total dose-length product (DLP) was 41.2 ± 2.9 mGy*cm, which was statistically significantly lower than of group B (257.4 ± 22.0 mGy*cm), corresponding to a mean dose reduction of 84% ( P<0.001). The mean CTDIvol for the control scans were 1.88 ± 0.09 mGy and 13.16 ± 0.40 mGy for groups A and B, respectively ( P < 0.001). The success rate in group A was 91.2% and 87.9% in group B ( P = 0.56). No negative effect on image-quality parameters, time of FNAC, and number of control scans were found.

Conclusion

We successfully developed a low-dose protocol for CT-guided MSK biopsies that maintains diagnostic accuracy and image quality at a fraction of the RD compared to the reference biopsy protocol at our clinic.

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.

Instituting a Low-dose CT-guided Lung Biopsy Protocol

RATIONALE AND OBJECTIVES

We aimed to evaluate whether implementation of a low-dose computed tomography (CT)-guided lung biopsy protocol, with the support of individual radiologists in the section, would lead to immediate and sustained decreases in radiation dose associated with CT-guided lung biopsies.

MATERIALS AND METHODS

A low-dose CT-guided lung biopsy protocol was developed with modifications of kilovoltage peak, milliamperes, and scan coverage. Out of 413 CT-guided lung biopsies evaluated over a 3-year period beginning in 2009, 175 performed with a standard protocol before the development of a low-dose protocol, and 238 performed with a low-dose protocol. The dose-length product (DLP) was recorded for each lung biopsy and retrospectively compared between the two protocols. Individual radiologist level DLPs were also compared before and after the protocol change.

RESULTS

The mean biopsy dose decreased by 64.4% with the low-dose protocol (113.8 milligray centimeters versus 319.7 milligray centimeters; P < 0.001). This decrease in radiation dose persisted throughout the entire 18 months evaluated following the protocol change. After the protocol change, each attending radiologist demonstrated a decrease in administered radiation dose. The diagnostic outcome rate and complication rate were unchanged over the interval.

CONCLUSIONS

Implementation of a low-dose CT-guided lung biopsy protocol resulted in an immediate reduction in patient radiation dose that was seen with all attending radiologists and persisted for at least 18 months. Such an intervention may be considered at other institutions wishing to reduce patient doses.

Reducing Patient Radiation Exposure From CT Fluoroscopy-Guided Lumbar Spine Pain Injections by Targeting the Planning CT

OBJECTIVE

CT fluoroscopy-guided lumbar spine pain injections typically include a preprocedural planning CT that contributes considerably to patient dose. The purpose of this study was to quantify the degree of radiation exposure reduction achieved by modifying only the planning CT component of the examination.

MATERIALS AND METHODS

A retrospective review was performed of 80 CT fluoroscopy-guided lumbar spine injections. Forty patients were scanned with a standard protocol using automatic tube current modulation (method A). Another 40 patients were scanned using a new technique that fixed the tube current of the planning CT to either 50 or 100 mA on the basis of the patient's anteroposterior diameter and that reduced the z-axis coverage (method B). Dose-length products (DLPs) were compared for the two methods.

RESULTS

The mean maximal tube current for the planning CT was 435.0 mA for method A and 67.5 mA for method B. The mean z-axis was shorter for method B at 6.5 cm than for method A at 9.6 cm (p < 0.0001). The mean DLP for the planning CT was 11 times lower for method B than for method A: 27.9 versus 313.1 mGy × cm, respectively (p < 0.0001). When method B was used, the mean DLP for the total procedure (i.e., planning CT plus CT fluoroscopy components) was reduced by 78%. There was no significant difference between methods A and B in CT fluoroscopy time (p = 0.37). All procedures were technically successful.

CONCLUSION

A nearly fivefold reduction in radiation exposure can be achieved in CT fluoroscopy-guided lumbar spine pain injections through modifications to the planning CT alone.