Safety and efficacy of CT-guided percutaneous microwave ablation for stage I non-small cell lung cancer in patients with comorbid idiopathic pulmonary fibrosis.

OBJECTIVES: To evaluate the safety and efficacy of microwave ablation (MWA) for stage I non-small cell lung cancer (NSCLC) in patients with idiopathic pulmonary fibrosis (IPF). MATERIALS AND METHODS: A retrospective single-center cohort study was conducted in patients with clinical stage I NSCLC who underwent CT-guided MWA from Nov 2016 to Oct 2021. The patients were divided into the IPF group and the non-IPF group. The primary endpoints were 90-day adverse events and hospital length of stay (HLOS). The secondary endpoints included overall survival (OS) and progression-free survival (PFS). RESULTS: A total of 107 patients (27 with IPF and 80 without IPF) were finally included for analysis. No procedure-related acute exacerbation of IPF or death occurred post-MWA. The rates of adverse events were similar between the groups (48.6% vs. 47.7%; p = 0.998). The incidence of grade 3 adverse events in the IPF group was higher than that in the non-IPF group without a significant difference (13.5% vs. 4.6%; p = 0.123). Median HLOS was 5 days in both groups without a significant difference (p = 0.078). The 1-year and 3-year OS were 85.2%/51.6% in the IPF group, and 97.5%/86.4% in the non-IPF group. The survival of patients with IPF was significantly poorer than the survival of patients without IPF (p < 0.001). There was no significant difference for PFS (p = 0.271). CONCLUSION: MWA was feasible in the treatment of stage I NSCLC in patients with IPF. IPF had an adverse effect on the survival of stage I NSCLC treated with MWA. CLINICAL RELEVANCE STATEMENT: CT-guided microwave ablation is a well-tolerated and effective potential alternative treatment for stage I non-small cell lung cancer in patients with idiopathic pulmonary fibrosis. KEY POINTS: • Microwave ablation for stage I non-small cell lung cancer was well-tolerated without procedure-related acute exacerbation of idiopathic pulmonary fibrosis and death in patients with idiopathic pulmonary fibrosis. • No differences were observed in the incidence of adverse events between patients with idiopathic pulmonary fibrosis and those without idiopathic pulmonary fibrosis after microwave ablation (48.6% vs. 47.7%; p = 0.998). • The 1-year and 3-year overall survival rates (85.2%/51.6%) in the idiopathic pulmonary fibrosis group were worse than those in the non- idiopathic pulmonary fibrosis group (97.5%/86.4%) (p < 0.001).

High-Frequency Jet Ventilation Versus Spontaneous Respiration for Percutaneous Cryoablation of Lung Tumors: Comparison of Adverse Events and Procedural Efficiency.

BACKGROUND. High-frequency jet ventilation (HFJV) facilitates accurate probe placement in percutaneous ablation of lung tumors but may increase risk for adverse events, including systemic air embolism. OBJECTIVE. The purpose of this study was to compare major adverse events and procedural efficiency of percutaneous lung ablation with HFJV under general anesthesia to spontaneous respiration (SR) under moderate sedation. METHODS. This retrospective study included consecutive adults who underwent CT-guided percutaneous cryoablation of one or more lung tumors with HFJV or SR between January 1, 2017, and May 31, 2023. We compared major adverse events (Common Terminology Criteria for Adverse Events grade ≥ 3) within 30 days postprocedure and hospital length of stay (HLOS) of 2 days or more using logistic regression analysis. We compared procedure time, room time, CT guidance acquisition time, CT guidance radiation dose, total radiation dose, and pneumothorax using generalized estimating equations. RESULTS. Overall, 139 patients (85 women, 54 men; median age, 68 years) with 310 lung tumors (82% metastases) underwent 208 cryoablations (HFJV, n = 129; SR, n = 79). HFJV showed greater rates than SR for the treatment of multiple tumors per session (43% vs 19%, respectively; p = .02) and tumors in a nonperipheral location (48% vs 24%, p < .001). Major adverse event rate was 8% for HFJV and 5% for SR (p = .46). No systemic air embolism occurred. HLOS was 2 days or more in 17% of sessions and did not differ significantly between HFJV and SR (p = .64), including after adjusting for probe number per session, chronic obstructive pulmonary disease, and operator experience (p = .53). Ventilation modalities showed no significant difference in procedure time, CT guidance acquisition time, CT guidance radiation dose, or total radiation dose (all p > .05). Room time was longer for HFJV than SR (median, 154 vs 127 minutes, p < .001). For HFJV, the median anesthesia time was 136 minutes. Ventilation modalities did not differ in the frequencies of pneumothorax or pneumothorax requiring chest tube placement (both p > .05). CONCLUSION. HFJV appears to be as safe as SR but had longer room times. HFJV can be used in complex cases without significantly impacting HLOS of 2 days or more, procedure time, or radiation exposure. CLINICAL IMPACT. Selection of the ventilation modality during percutaneous lung ablation should be based on patient characteristics and anticipated procedural requirements as well as operator preference.

Usual Interstitial Pneumonia: Associations With Complications After Percutaneous Transthoracic Needle Lung Biopsy.

BACKGROUND. Changes in lung parenchyma elasticity in usual interstitial pneumonia (UIP) may increase the risk for complications after percutaneous transthoracic needle biopsy (PTNB) of the lung. OBJECTIVE. The purpose of this article was to investigate the association of UIP findings on CT with complications after PTNB, including pneumothorax, pneumothorax requiring chest tube insertion, and hemoptysis. METHODS. This retrospective single-center study included 4187 patients (mean age, 63.8 ± 11.9 [SD] years; 2513 men, 1674 women) who underwent PTNB between January 2010 and December 2015. Patients were categorized into a UIP group and non-UIP group by review of preprocedural CT. In the UIP group, procedural CT images were reviewed to assess for traversal of UIP findings by needle. Multivariable logistic regression analyses were performed to identify associations between the UIP group and needle traversal with postbiopsy complications, controlling for a range of patient, lesion, and procedural characteristics. RESULTS. The UIP and non-UIP groups included 148 and 4039 patients, respectively; in the UIP group, traversal of UIP findings by needle was observed in 53 patients and not observed in 95 patients. The UIP group, in comparison with the non-UIP group, had a higher frequency of pneumothorax (35.1% vs 17.9%, p < .001) and pneumothorax requiring chest tube placement (6.1% vs 1.5%, p = .001) and lower frequency of hemoptysis (2.0% vs 6.1%, p = .03). In multivariable analyses, the UIP group with traversal of UIP findings by needle, relative to the non-UIP group, showed independent associations with pneumothorax (OR, 5.25; 95% CI, 2.94-9.37; p < .001) and pneumothorax requiring chest tube placement (OR, 9.55; 95% CI, 3.74-24.38; p < .001). The UIP group without traversal of UIP findings by needle, relative to the non-UIP group, was not independently associated with pneumothorax (OR, 1.18; 95% CI, 0.71-1.97; p = .51) or pneumothorax requiring chest tube placement (OR, 1.08; 95% CI, 0.25-4.72; p = .92). The UIP group, with or without traversal of UIP findings by needle, was not independently associated with hemoptysis. No patient experienced air embolism or procedure-related death. CONCLUSION. Needle traversal of UIP findings is a risk factor for pneumothorax and pneumothorax requiring chest tube placement after PTNB. CLINICAL IMPACT. When performing PTNB in patients with UIP, radiologists should plan a needle trajectory that does not traverse UIP findings, when possible.

Adrenal Vein Sampling: Tips and Tricks.

Adrenal vein sampling (AVS) is the standard method for distinguishing unilateral from bilateral sources of autonomous aldosterone production in patients with primary aldosteronism. This procedure has been performed at limited specialized centers due to its technical complexity. With recent advances in imaging technology and knowledge of adrenal vein anatomy in parallel with the development of adjunctive techniques, AVS has become easier to perform, even at nonspecialized centers. Although rare, anatomic variants of the adrenal veins can cause sampling failure or misinterpretation of the sampling results. The inferior accessory hepatic vein and the inferior emissary vein are useful anatomic landmarks for right adrenal vein cannulation, which is the most difficult and crucial step in AVS. Meticulous assessment of adrenal vein anatomy on multidetector CT images and the use of a catheter suitable for the anatomy are crucial for adrenal vein cannulation. Adjunctive techniques such as intraprocedural cortisol assay, cone-beam CT, and coaxial guidewire-catheter techniques are useful tools to confirm right adrenal vein cannulation or to troubleshoot difficult blood sampling. Interventional radiologists should be involved in interpreting the sampling results because technical factors may affect the results. In rare instances, bilateral adrenal suppression, in which aldosterone-to-cortisol ratios of both adrenal glands are lower than that of the inferior vena cava, can be encountered. Repeat sampling may be necessary in this situation. Collaboration with endocrinology and laboratory medicine services is of great importance to optimize the quality of the samples and for smooth and successful operation. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Radiation protection in CT-guided interventions: does real-time dose visualisation lead to a reduction in radiation dose to participating radiologists? A single-centre evaluation.

AIM: To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. MATERIALS AND METHODS: The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. RESULTS: In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 µSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 µSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002). CONCLUSION: The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

The influence of respiratory movement on preoperative CT-guided localization of lung nodules.

AIM: To evaluate the motion amplitude of lung nodules in different locations during preoperative computed tomography (CT)-guided localization, and the influence of respiratory movement on CT-guided percutaneous lung puncture. MATERIALS AND METHODS: A consecutive cohort of 398 patients (123 men and 275 women with a mean age of 53.9 ± 10.7 years) who underwent preoperative CT-guided lung nodule localization from May 2021 to Apr 2022 were included in this retrospective study. The respiratory movement-related nodule amplitude in the cranial-caudal direction during the CT scan, characteristics of patients, lesions, and procedures were statistically analyzed. Univariate and multivariate logistic regression analyses were used to evaluate the influence of these factors on CT-guided localization. RESULTS: The nodule motion distribution showed a statistically significant correlation within the upper/middle (lingular) and lower lobes (p<0.001). Motion amplitude was an independent risk factor for CT scan times (p=0.011) and procedure duration (p=0.016), but not for the technical failure rates or the incidence of complications. Puncture depth was an independent risk factor for the CT scan times, procedure duration, technical failure rates, and complications (p<0.01). Female, prone, and supine (as opposed to lateral) positions were significant protective factors for pneumothorax, while the supine position was an independent risk factor for parenchymal hemorrhage (p=0.025). CONCLUSION: Respiratory-induced motion amplitude of nodules was greater in the lower lobes, resulting in more CT scan times/radiation dose and longer localization duration, but showed no statistically significant influence on the technical success rates or the incidence of complications during preoperative CT-guided localization.

Advanced Interventional Procedures for Knee Osteoarthritis: What Is the Current Evidence?

The prevalence of knee osteoarthritis (OA) is the highest among all joints and likely to increase over the coming decades. Advances in the repertoire of diagnostic capabilities of imaging and an expansion in the availability and range of image-guided interventions has led to development of more advanced interventional procedures targeting pain related to OA pain while improving the function of patients presenting with this debilitating condition. We review the spectrum of established advanced interventional procedures for knee OA, describe the techniques used to perform these procedures safely, and discuss the clinical evidence supporting each of them.

CT-guided percutaneous transthoracic needle biopsy for anterior mediastinal lymphoma: the role of PET/CT.

BACKGROUND: Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is not recommended as the diagnostic modality of choice for anterior mediastinal lymphoma, despite its advantages of minimal invasiveness and easy accessibility. PURPOSE: To identify the modifiable risk factors for non-diagnostic results from CT-guided PTNB for anterior mediastinal lymphoma. MATERIAL AND METHODS: This retrospective study identified CT-guided PTNB for anterior mediastinal lesions diagnosed as lymphoma between May 2007 and December 2021. The diagnostic sensitivity and complications were investigated. The appropriateness of PTNB targeting was evaluated using positron emission tomography (PET)/CT and images from intra-procedural CT-guided PTNB. Targeting was considered inappropriate when the supposed trajectory of the cutting needle was within a region of abnormally low metabolism. The risk factors for non-diagnostic results were determined using logistic regression analysis. RESULTS: A total of 67 PTNBs in 60 patients were included. The diagnostic sensitivity for lymphoma was 76.1% (51/67), with an immediate complication rate of 4.5% (3/67). According to the PET/CT images, PTNB targeting was inappropriate in 10/14 (71.4%) of the non-diagnostic PTNBs but appropriate in all diagnostic PTNBs (P <0.001). Inappropriate targeting was the only significant risk factor for non-diagnostic results (odds ratio = 203.69; 95% confidence interval = 8.17-999.99; P = 0.001). The number of specimen acquisitions was not associated with non-diagnostic results (P = 0.40). CONCLUSIONS: Only inappropriate targeting of the non-viable portion according to PET/CT was an independent risk factor for non-diagnostic results. Acquiring PET/CT scans before biopsy and targeting the viable portion on PET/CT may help improve the diagnostic sensitivity of PTNB.

Factors affecting the success of CT-guided core biopsy of musculoskeletal lesions with a 13-G needle.

OBJECTIVE: To determine the value of CT-guided bone core biopsy and investigate factors that affect diagnostic yield and biopsy outcome. MATERIALS AND METHODS: The single-centre retrospective analysis included 447 patients who had CT-guided core biopsy with a 13-G needle (Bonopty®) from January 2016 to December 2021. Histological results or ≥ 6 months of clinical and radiological follow-up served as outcome references. A successful biopsy was classified as "diagnostic" when a definitive diagnosis was made and "adequate" when only the malignant or benign nature of the tumour could be determined. Biopsies were "nondiagnostic" when the nature of the lesion could not be determined. The occult lesions were defined as not seen on CT but visible on other modalities. RESULTS: In 275 (62%) females and 172 (38%) males, the overall success rate was 85% (383 biopsies), with 314 (70%) diagnostic biopsies and 69 (15%) adequate biopsies. There was no relationship between biopsy success and the localisation of the lesion, length of biopsy material, or number of biopsy attempts. The lesions' nature had a statistically significant effect on biopsy success with lytic and mixed lesions having the highest success rate. Occult lesions had the lowest success rate. CONCLUSION: CT-guided bone core biopsy is an effective method in the workup of musculoskeletal diseases with the highest success rate in lytic and mixed lesions. No apparent relationship was found between biopsy success and biopsy length, number of attempts, or localisation of the lesion.

Clinical impact of diagnostic image-guided injections for musculoskeletal pain work-up in adolescent and adult patients at a children's hospital: initial results.

OBJECTIVE: To assess the clinical impact of diagnostic musculoskeletal (MSK) injections on treatment decision-making in adolescent and adult patients at a children's hospital. MATERIALS AND METHODS: Retrospective study in patients who underwent diagnostic MSK injections by fluoroscopy or ultrasound (US) between 8/2020 and 3/2023 at a children's hospital. Patients received ropivacaine and triamcinolone acetonide at pain site, reporting quantitative FACES pain score prior to, immediately following, and 2-3 days following injection. Impact on patient care was subsequently assessed. RESULTS: A total of 109 diagnostic fluoroscopic or US MSK injection referrals (mean: 17.6 years old) were included, most commonly hip (76.2%), ankle (9.2%), and iliopsoas tendon sheath (8.3%). Pain improvement occurred in 89.0% immediately and 67.9% 2-3 days after MSK injection, with net 84.4% exhibiting improvement based on pain scores and clinical exams. When there was pain improvement at the site of injection, there was a statistically higher incidence of operative intervention or additional therapeutic injections compared with the cohort that did not have symptom improvement (88% versus 35.3%, P < 0.0001). For the 15.6% (N = 17) of referrals that did not have pain improvement, 17.6% (n = 3) ultimately had an operative intervention at a separate site from the diagnostic injection, as an alternative etiology for the pain was found. CONCLUSION: Image-guided MSK injections play an important role in the management of musculoskeletal disorders. 84.4% of referrals experienced symptom relief, improving confidence for treatment decision-making. Importantly, 15.6% of patients were found to have an alternative etiology for symptoms, altering management altogether.

Contrast flow in CT-guided lumbar interlaminar epidural steroid injections: does needle position effect the laterality of contrast flow?

PURPOSE: To evaluate the effect of needle position on the laterality of contrast flow in CT-guided lumbar interlaminar epidural steroid injections. MATERIALS AND METHODS: A retrospective review of consecutive CT-guided interlaminar lumbar epidural steroid injections was performed. The terminal needle tip position (midline or lateral) and the laterality of epidural contrast were evaluated by two readers. Contrast flow pattern was classified as ipsilateral to needle trajectory, bilateral, or contralateral. Bilateral flow was further divided into asymmetric, symmetrical, or asymmetric to the contralateral side. Inter-reader agreement was calculated with the kappa statistic. The relationship of needle position to contrast laterality was calculated with the chi statistic. Pain scores were compared for bilateral and unilateral flows with a two-tailed T test for independent means. RESULTS: A total of 250 injections were included in 204 patients, with an age range of 24 to 93 years. The most commonly injected level (145/250) was L4-L5. Agreement between the two readers was almost perfect and substantial (kappa 0.751-0.880). The majority of injections (154/250) demonstrated contrast flow ipsilateral to the needle trajectory, 90/250 demonstrated bilateral flow, and 6/250 had contralateral flow. Of the 90 cases with bilateral flow, 80% were performed with a midline terminal needle position (p < 0.001). There was no difference in immediate post-procedure pain scores between patients with ipsilateral or bilateral contrast flow. CONCLUSION: For interlaminar epidural steroid injections, a midline terminal needle tip position has a greater probability of producing bilateral contrast flow compared to a lateral terminal needle tip position.

Imaging in Interventional Radiology: 2043 and Beyond.

Since its inception in the early 20th century, interventional radiology (IR) has evolved tremendously and is now a distinct clinical discipline with its own training pathway. The arsenal of modalities at work in IR includes x-ray radiography and fluoroscopy, CT, MRI, US, and molecular and multimodality imaging within hybrid interventional environments. This article briefly reviews the major developments in imaging technology in IR over the past century, summarizes technologies now representative of the standard of care, and reflects on emerging advances in imaging technology that could shape the field in the century ahead. The role of emergent imaging technologies in enabling high-precision interventions is also briefly reviewed, including image-guided ablative therapies.

Cone-Beam CT With Enhanced Needle Guidance and Augmented Fluoroscopy Overlay: Applications in Interventional Radiology.

Digital flat-panel detector cone-beam CT (CBCT), introduced in the early 2000s, was historically used in interventional radiology primarily for liver-directed therapies. However, contemporary advanced imaging applications, including enhanced needle guidance and augmented fluoroscopy overlay, have evolved substantially over the prior decade and now work synergistically with CBCT guidance to overcome limitations encountered with other imaging modalities. CBCT with advanced imaging applications has become increasingly used to facilitate a broad range of minimally invasive procedures, particularly relating to pain and musculoskeletal interventions. Potential advantages of CBCT with advanced imaging applications include greater accuracy for complex needle paths, improved targeting in the presence of metal artifact, enhanced visualization during injection of contrast medium or cement, increased ease when space in the gantry is limited, and reduced radiation doses versus conventional CT guidance. Nonetheless, CBCT guidance remains underutilized, partly relating to lack of familiarity with the technique. This article describes the practical implementation of CBCT with enhanced needle guidance and augmented fluoroscopy overlay and depicts the technique's application for an array of interventional radiology procedures, including epidural steroid injections, celiac plexus block and neurolysis, pudendal block, spine ablation, percutaneous osseous ablation fixation and osteoplasty, biliary recanalization, and transcaval type II endoleak repair.

Frequency and Risk Factors for Air Embolism in Computed Tomography Fluoroscopy-Guided Biopsy of Lung Tumor With the Use of Noncoaxial Automatic Needle.

PURPOSE: The aim of the study is to analyze incidence and risk factors for air embolism during computed tomography (CT) fluoroscopy-guided lung biopsies using noncoaxial automatic needle. MATERIALS AND METHODS: Between February 2014 and December 2019, 204 CT fluoroscopy-guided lung biopsies (127 men; mean age, 70.6 years) using noncoaxial automatic needle under inspiratory breath holding were performed. We retrospectively evaluated the incidence of air embolism as presence of air in the systemic circulation on whole-chest CT images obtained immediately after biopsy. Risk factors of the patient, tumor and procedural factors (size, location and type of nodule, distance from the pleura, the level of the lesion relative to the left atrium, emphysema, patient position, penetration of a pulmonary vein, etc) were analyzed. RESULTS: The technical success rate was 97.1%. Air embolism was radiologically identified in 8 cases (3.92%, 7 males; size, 21.6 ± 18.2 mm; distance to pleura, 11.9 ± 14.5 mm). Two patients showed overt symptoms and the others were asymptomatic. Independent risk factors were needle penetration of the pulmonary vein ( P = 0.0478) and higher location relative to left atrium ( P = 0.0353). Size, location and type of nodule, distance from the pleura, emphysema, patient position, and other variables were not significant risk factors. As other complications, pneumothorax and alveolar hemorrhage were observed in 57.4% and 77.5%, respectively. CONCLUSIONS: In CT fluoroscopy-guided lung biopsy using the noncoaxial automatic needles, radiological incidence of air embolism was 3.92%. Given the frequency of air embolism, it is necessary to incorporate this into postprocedure imaging and clinical evaluation.

Patient exposure dose in interventional cardiology per clinical and technical complexity levels. Part 1: results of the VERIDIC project.

BACKGROUND: Patients can be exposed to high skin doses during complex interventional cardiology (IC) procedures. PURPOSE: To identify which clinical and technical parameters affect patient exposure and peak skin dose (PSD) and to establish dose reference levels (DRL) per clinical complexity level in IC procedures. MATERIAL AND METHODS: Validation and Estimation of Radiation skin Dose in Interventional Cardiology (VERIDIC) project analyzed prospectively collected patient data from eight European countries and 12 hospitals where percutaneous coronary intervention (PCI), chronic total occlusion PCI (CTO), and transcatheter aortic valve implantation (TAVI) procedures were performed. A total of 62 clinical complexity parameters and 31 technical parameters were collected, univariate regressions were performed to identify those parameters affecting patient exposure and define DRL accordingly. RESULTS: Patient exposure as well as clinical and technical parameters were collected for a total of 534 PCI, 219 CTO, and 209 TAVI. For PCI procedures, body mass index (BMI), number of stents ≥2, and total stent length >28 mm were the most prominent clinical parameters, which increased the PSD value. For CTO, these were total stent length >57 mm, BMI, and previous anterograde or retrograde technique that failed in the same session. For TAVI, these were male sex, BMI, and number of diseased vessels. DRL values for Kerma-area product (PKA), air kerma at patient entrance reference point (Ka,r), fluoroscopy time (FT), and PSD were stratified, respectively, for 14 clinical parameters in PCI, 10 in CTO, and four in TAVI. CONCLUSION: Prior knowledge of the key factors influencing the PSD will help optimize patient radiation protection in IC.

Effect of the respiratory motion of pulmonary nodules on CT-guided percutaneous transthoracic needle biopsy.

BACKGROUND: Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is highly affected by respiratory motion; however, respiratory motion of target nodule during the PTNB and its effect on CT-guided lung biopsy have not been studied. PURPOSE: To investigate the effect of the respiratory motion of pulmonary nodules on CT-guided PTNB. MATERIAL AND METHODS: We retrospectively reviewed the procedural CT scans of 426 pulmonary nodules that underwent PTNB during quiet breathing. Maximal and average respiratory motions were measured using the difference of table position of the targeted nodule between multiple procedural scans. Diagnostic performance, complications, and technical factors of PTNB in nodules with large motion (maximal motion >1 cm) were compared with those in nodules with small motion (≤1 cm). RESULTS: The mean maximal and average respiratory motions between tidal volume breathing were 5.4 ± 4.4 and 2.7 ± 2.6 mm, respectively. Sensitivity and accuracy were 93.1% and 96.1% in nodules with large motion, compared with 94.7% and 95.9% in nodules with small motion, respectively. Respiratory targeting (P < 0.001), needle modulation (P < 0.001), motion artifact of target (P < 0.001), target disappearance from scans (P < 0.001), and number of performed CT scans (P < 0.001) were significantly higher in the large motion group, with no significant difference in radiation dose and complications between the groups. CONCLUSION: The respiratory motion of pulmonary nodules during CT-guided PTNB may cause technical difficulties but does not affect diagnostic performance nor complications associated with PTNB.

Local reference and achievable dose levels for vascular and enterostomy access procedures in pediatric interventional radiology.

BACKGROUND: Knowledge of radiation quantities delivered in routine practice is an essential responsibility of a pediatric interventional radiology department. OBJECTIVE: To review radiation indices in frequently performed vascular and enterostomy access procedures at a quaternary pediatric hospital to formulate dosimetric reference levels and achievable levels. MATERIALS AND METHODS: A retrospective review of patient demographics, procedure information and quantitative dose metrics over a 2-year period was performed. Dosimetric details for common procedures (central line insertions, gastrostomy/gastrojejunostomy insertions and maintenance) were evaluated, correlated with demographic data and stratified across five weight groups (0-5 kg, 5-15 kg, 15-30 kg, 30-50 kg, 50-80 kg). Achievable (50th percentile) and reference (75th percentile) levels with confidence intervals were established for each procedure. RESULTS: Within the evaluation period, 3,165 studies satisfied the inclusion criteria. Five were classified as device insertions (peripherally inserted central catheter, n=1,145; port-a-catheter, n=321; central venous line, n=285; gastrostomy-tube [G-tube], n=262, and gastrojejunostomy-tube [GJ-tube], n=66), and two were classified as maintenance procedures (G-tube, n=358, and GJ-tube, n=728, checks, exchanges and reinsertions). Representative reference and achievable levels were calculated for each procedure category and weight group. CONCLUSION: This work highlights the creation of local reference and achievable levels for common pediatric interventional procedures. These data establish a dosimetric reference to understand the quantity of radiation routinely applied, allowing for improved relative radiation risk assessment and enriched communication to interventionalists, health care providers, parents and patients.

Cone-beam computed tomography-assisted percutaneous gastrostomy tube insertion in children with challenging anatomy.

BACKGROUND: Percutaneous radiological gastrostomy tube insertion is a common procedure in children. An approach using ultrasound and fluoroscopy may not be feasible in patients with challenging anatomy; therefore, advanced techniques or other imaging modalities may be required. OBJECTIVE: To describe our experience using cone-beam computed tomography (CT)-assisted percutaneous gastrostomy insertion in pediatric patients with challenging anatomy. MATERIALS AND METHODS: A retrospective review was performed in children who underwent cone-beam CT-assisted percutaneous radiologic gastrostomy between January 2015 and July 2019. Indications, technique, outcomes, complications, and radiation dose (reference-point air kerma, air kerma area product) were assessed through chart and imaging review. Descriptive statistics only were used. RESULTS: Twenty-seven procedures were attempted in 26 patients. Reasons for utilizing cone-beam CT guidance were high-positioned stomach (n = 10), interposing bowel loops and liver (n = 19), omphalocele (n = 1), severe scoliosis (n = 1), and ventriculoperitoneal shunt (n = 1). Technical success was 85% (23/27). Mean procedure time was 96 min (range 50-131 min). No safe access route into the stomach was encountered in four patients; three were referred for surgical gastrostomy and one had a successful re-attempt. Radiation dose data was obtained from 19 procedures (17 successful) with a total dose in successful procedures ranging from 8.1 to 63.6 mGy (average 26.2 mGy, median 24.9 mGy). The number of cone-beam CT acquisitions per procedure ranged from 1 to 4. Major complication frequency was 11% (3/27) (bleeding, peritonitis, and aspiration pneumonia); minor complication frequency was 3.7% (1/27). CONCLUSION: This study shows that cone-beam CT guidance can be useful for assisting percutaneous radiologic gastrostomy in children with challenging anatomy.

A Prototype Software System for Intra-procedural Staff Dose Monitoring and Virtual Reality Training for Fluoroscopically Guided Interventional Procedures.

Staff dose management in fluoroscopically guided interventional procedures is a continuing problem. The scattered radiation display system (SDS), which our group has developed, provides in-room visual feedback of scatter dose to staff members during fluoroscopically guided interventional (FGI) procedures as well as extra-procedure staff and resident training. There have been a number of virtual safety training systems developed that provide detailed feedback for staff, but utilize expensive graphics processing units (GPUs) and dosimeter systems, or interaction with the x-ray system in a manner which entails additional radiation exposure and is not compatible with the As Low as Reasonably Achievable paradigm. The SDS, on the other hand, incorporates a library of look-up-table (LUT) room scatter distributions determined using the EGSnrc Monte Carlo software, which facilitates accurate and rapid system update without the need for GPUs. Real-time display of these distributions is provided for feedback to staff during a procedure. After a procedure is completed, machine parameter and staff position log files are stored, retaining all of the exposure and geometric information for future review. A graphic user interface (GUI) in Unity3D enables procedure playback and interactive virtual-reality (VR) staff and resident training with virtual control of exposure conditions using an Oculus headset and controller. Improved staff and resident awareness using this system should lead to increased safety and reduced occupational dose.

A Novel Laser Angle Selection System for Computed Tomography-Guided Percutaneous Transthoracic Needle Biopsies.

Purpose: To evaluate a novel laser angle selection system (LASS) for improving the efficiency of a computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB). Methods: Thirty-eight patients referred for CT-guided PTNB were randomly separated into a LASS-assisted puncture group (18 patients) or conventional freehand control group (20 patients). The puncture time, number of control CT scans, and patients' radiation dose were compared for each group. Results: The lesion size, target-to-pleural distance, planned puncture depth, and angle of the two groups were not significantly different. LASS-assisted PTNB significantly reduced the number of control scans (1.7 ± 0.8 vs 3.5 ± 1.5, P < .001) and the mean operation time (12.0 ± 4.3 min vs 28.8 ± 13.3 min, P < .001) compared with the conventional method. The corresponding room time (27.1 ± 6.6 min vs 44.1 ± 14.4 min, P < .001) and total radiation dose (7.9 ± 1.0 mSv vs 10.1 ± 1.7 mSv, P < .001) of each procedure also decreased significantly. Fifty-six percent (10/18) of the operations hit the target on the first needle pass when using LASS compared with 10% (2/20) using the conventional method. Conclusions: Compared with a conventional method, this novel laser angle simulator improves puncture efficiency with fewer needle readjustments and reduces patient radiation dose.