Percutaneous Endoscopy and Image-guided Retrieval of Dropped Gallstones - A Case Series.

BACKGROUND: Recurrent abscesses can happen due to dropped gallstones (DGs) after laparoscopic cholecystectomy (LC). Recognition and appropriate percutaneous endoscopy and image-guided treatment options can decrease morbidity associated with this condition. MATERIALS AND METHODS: We report a minimally invasive endoscopy and image-guided technique for retrieval of dropped gallstones in a series of 6 patients (M/F=3/3; median age: 75.5 years [68 to 82]) presenting with recurrent or chronic intra-abdominal abscesses secondary to dropped gallstones. Technical success was defined as the visualization and retrieval of all stones. DGs were identified on pre-procedure imaging. Number of abscesses recurrence was 12 (1/6), 1 (3/6), and 0 (2/6) with a median interval of 2 months (1 to 21) between cholecystectomy and abscess development. RESULTS: Percutaneous endoscopy and fluoroscopy guidance were utilized in all cases. Technical success was achieved in 4 patients (66%). The median procedure time was 65.8 minutes (39 to 136). The median fluoroscopy time and dose were 12.6 min (3.3 to 67) and 234 mGy (31 to 1457), respectively. There were no intraprocedure and postprocedure complications. No abscess recurrence was reported among successful procedures during a median follow-up of 193 days (51 to 308). CONCLUSION: Percutaneous image and endoscopy-guided lithotripsy/lithectomy are safe and effective. This technique is a suitable alternative to open surgery for dropped gallstones. LEVEL OF EVIDENCE: Level 4, Case Series.

Multicenter Quantification of Radiation Exposure and Associated Risks for Prostatic Artery Embolization in 1476 Patients.

Background Prostatic artery embolization (PAE) is a safe, minimally invasive angiographic procedure that effectively treats benign prostatic hyperplasia; however, PAE-related patient radiation exposure and associated risks are not completely understood. Purpose To quantify radiation dose and assess radiation-related adverse events in patients who underwent PAE at multiple centers. Materials and Methods This retrospective study included patients undergoing PAE for any indication performed by experienced operators at 10 high-volume international centers from January 2014 to May 2021. Patient characteristics, procedural and radiation dose data, and radiation-related adverse events were collected. Procedural radiation effective doses were calculated by multiplying kerma-area product values by an established conversion factor for abdominopelvic fluoroscopy-guided procedures. Relationships between cumulative air kerma (CAK) or effective dose and patient body mass index (BMI), fluoroscopy time, or radiation field area were assessed with linear regression. Differences in radiation dose stemming from radiopaque prostheses or fluoroscopy unit type were assessed using two-sample t tests and Wilcoxon rank sum tests. Results A total of 1476 patients (mean age, 69.9 years ± 9.0 [SD]) were included, of whom 1345 (91.1%) and 131 (8.9%) underwent the procedure with fixed interventional or mobile fluoroscopy units, respectively. Median procedure effective dose was 17.8 mSv for fixed interventional units and 12.3 mSv for mobile units. CAK and effective dose both correlated positively with BMI (R2 = 0.15 and 0.17; P < .001) and fluoroscopy time (R2 = 0.16 and 0.08; P < .001). No radiation-related 90-day adverse events were reported. Patients with radiopaque implants versus those without implants had higher median CAK (1452 mGy [range, 900-2685 mGy] vs 1177 mGy [range, 700-1959 mGy], respectively; P = .01). Median effective dose was lower for mobile than for fixed interventional systems (12.3 mSv [range, 8.5-22.0 mSv] vs 20.4 mSv [range, 13.8-30.6 mSv], respectively; P < .001). Conclusion Patients who underwent PAE performed with fixed interventional or mobile fluoroscopy units were exposed to a median effective radiation dose of 17.8 mSv or 12.3 mSv, respectively. No radiation-related adverse events at 90 days were reported. © RSNA, 2024 See also the editorial by Mahesh in this issue.

Prostatic Artery Embolization in Patients with Refractory Lower Urinary Tract Symptoms after a Prior Minimally Invasive Surgical Treatment.

The purpose of this study was to report on prostatic artery embolization (PAE) outcomes in patients with refractory or recurrent lower urinary tract symptoms (LUTSs) due to benign prostatic hyperplasia (BPH) who had previously undergone a minimally invasive surgical technique (MIST). A single-center retrospective study identified 16 eligible patients. Baseline prostate volume at the time of PAE was 112.9 mL (SD ± 52.7). There were no adverse events throughout the follow-up period. There was significant improvement in International Prostate Symptom Score and quality of life from baseline of 23.5 (SD ± 5.1) and 4.9 (SD ± 0.9), respectively, to the last follow-up of 11.6 (SD ± 7.2) and 2 (SD ± 1.6), respectively. There was nonsignificant improvement in sexual function after PAE compared with baseline after MIST. PAE can be a safe and effective treatment in patients who have undergone prior MIST without negatively impacting erectile or ejaculatory function.

Adverse Events of Surgical Drain Placement: An Analysis of the NSQIP Database.

BACKGROUND: Surgical site drainage is important to prevent hematoma, seroma, and abscess formation. However, the placement of drain placement also predispose patients to several postoperative complications. The aim of this study is to clarify the risk-benefit profile of surgical drain placement. METHODS: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) Procedure-Targeted Databases were used to identify patients who underwent hepatectomy, pancreatectomy, nephrectomy, cystectomy, and prostatectomy. Patients who underwent each procedure were divided into 2 groups based on intraoperative drain placement. Propensity score-matched cohorts of these 2 groups were compared in terms of postoperative adverse events, readmission, reoperation, and length of stay. RESULTS: Hepatectomy patients with drains experienced organ space infections (P < .001), sepsis (P < .001), and readmission (P = .021) more often than patients without drains. Patients who underwent pancreatectomy and had drains placed experienced wound dehiscence less frequently than those without drains (P = .04). For hepatectomy, pancreatectomy, nephrectomy, and prostatectomy populations, patients with drains had longer lengths of stay (P < .05). Matched populations across all procedures did not differ in terms of reoperation rate. DISCUSSION: Prophylactic surgical drain placement may be associated with increased infectious complications and prolonged length of stay. Further studies are needed to elucidate the complete adverse event profile of surgical drains. Nonetheless, outcomes may be improved with better patient selection or advancements in drain technology.

Direct comparison and reproducibility of two segmentation methods for multicompartment dosimetry: round robin study on radioembolization treatment planning in hepatocellular carcinoma.

PURPOSE: Investigate reproducibility of two segmentation methods for multicompartment dosimetry, including normal tissue absorbed dose (NTAD) and tumour absorbed dose (TAD), in hepatocellular carcinoma patients treated with yttrium-90 (90Y) glass microspheres. METHODS: TARGET was a retrospective investigation in 209 patients with < 10 tumours per lobe and at least one tumour ≥ 3 cm ± portal vein thrombosis. Dosimetry was compared using two distinct segmentation methods: anatomic (CT/MRI-based) and count threshold-based on pre-procedural 99mTc-MAA SPECT. In a round robin substudy in 20 patients with ≤ 5 unilobar tumours, the inter-observer reproducibility of eight reviewers was evaluated by computing reproducibility coefficient (RDC) of volume and absorbed dose for whole liver, whole liver normal tissue, perfused normal tissue, perfused liver, total perfused tumour, and target lesion. Intra-observer reproducibility was based on second assessments in 10 patients ≥ 2 weeks later. RESULTS: 99mTc-MAA segmentation calculated higher absorbed doses compared to anatomic segmentation (n = 209), 43.9% higher for TAD (95% limits of agreement [LoA]: - 49.0%, 306.2%) and 21.3% for NTAD (95% LoA: - 67.6%, 354.0%). For the round robin substudy (n = 20), inter-observer reproducibility was better for anatomic (RDC range: 1.17 to 3.53) than 99mTc-MAA SPECT segmentation (1.29 to 7.00) and similar between anatomic imaging modalities (CT: 1.09 to 3.56; MRI: 1.24 to 3.50). Inter-observer reproducibility was better for larger volumes. Perfused normal tissue volume RDC was 1.95 by anatomic and 3.19 by 99mTc-MAA SPECT, with corresponding absorbed dose RDC 1.46 and 1.75. Total perfused tumour volume RDC was higher, 2.92 for anatomic and 7.0 by 99mTc-MAA SPECT with corresponding absorbed dose RDC of 1.84 and 2.78. Intra-observer variability was lower for perfused NTAD (range: 14.3 to 19.7 Gy) than total perfused TAD (range: 42.8 to 121.4 Gy). CONCLUSION: Anatomic segmentation-based dosimetry, versus 99mTc-MAA segmentation, results in lower absorbed doses with superior reproducibility. Higher volume compartments, such as normal tissue versus tumour, exhibit improved reproducibility. TRIAL REGISTRATION: NCT03295006.

Portal Vein Recanalization-Transjugular Intrahepatic Portosystemic Shunt (PVR-TIPS) Facilitates Liver Transplantation in Cirrhotic Patients with Occlusive Portal Vein Thrombosis.

Portal vein thrombosis (PVT) is a heterogeneous condition with multiple possible etiologies and to varying degrees has historically limited candidacy for liver transplant (LT) in the cirrhotic patient population due to resultant difficulties in constructing a robust portal vein anastomosis. While intraoperative approaches to managing PVT are well-described, methods which approximate normal portal physiology are not always feasible depending on the extent of PVT, and other nonphysiologic techniques are linked with substantial morbidity and poor long-term outcomes. Portal vein recanalization-transjugular intrahepatic portosystemic shunt (PVR-TIPS) creation is an efficacious method of restoring physiologic portal flow in cirrhotic patients prior to LT allowing for end-to-end PV anastomosis, and is the product of decades-long institutional expertise in TIPS/LT and the support of a multidisciplinary liver tumor board. To follow is a review of the pertinent pathophysiology of PVT in cirrhosis, the rationale leading to the development and subsequent evolution of the PVR-TIPS procedure, technical lessons learned, and a summary of outcomes to date.

Chemical Shift MRI Monitoring of Chemoembolization Delivery for Hepatocellular Carcinoma: Multicenter Feasibility of Initial Clinical Translation.

Purpose To demonstrate the feasibility of using chemical shift fat-water MRI methods to visualize and measure intrahepatic delivery of ethiodized oil to liver tumors following conventional transarterial chemoembolization (cTACE). Materials and Methods Twenty-eight participants (mean age, 66 years ± 8 [SD]; 22 men) with hepatocellular carcinoma (HCC) treated with cTACE were evaluated with follow-up chemical shift MRI in this Health Insurance Portability and Accountability Act-compliant prospective, institutional review board-approved study. Uptake of ethiodized oil was evaluated at 1-month follow-up chemical shift MRI. Measurements of tumor size (MRI and CT), attenuation and enhancement (CT), fat content percentage, and tumor:normal ratio (MRI) were compared by lesion for responders versus nonresponders, as assessed with modified Response Evaluation Criteria in Solid Tumors and European Association for the Study of the Liver (EASL) criteria. Adverse events and overall survival by the Kaplan-Meier method were secondary end points. Results Focal tumor ethiodized oil retention was 46% (12 of 26 tumors) at 24 hours and 47% (18 of 38 tumors) at 1 month after cTACE. Tumor volume at CT did not differ between EASL-defined responders and nonresponders (P = .06). Tumor ethiodized oil volume measured with chemical shift MRI was statistically significantly higher for EASL-defined nonresponders (P = .02). Doxorubicin dosing (P = .53), presence of focal fat (P = .83), and a combined end point of focal fat and low doxorubicin dosing (P = .97) did not stratify overall survival after cTACE. Conclusion Chemical shift MRI allowed for assessment of tumor delivery of ethiodized oil out to 1 month after cTACE in participants with HCC and demonstrated tumor ethiodized oil volume as a potential tool for stratification of tumor response by EASL criteria. Keywords: MRI, Chemical Shift Imaging, CT, Hepatic Chemoembolization, Ethiodized Oil Clinicaltrials.gov registration no.: NCT02173119 Supplemental material is available for this article. © RSNA, 2023.

Evolution of Personalized Dosimetry for Radioembolization of Hepatocellular Carcinoma.

Yttrium-90 transarterial radioembolization (TARE) has progressed from a salvage or palliative lobar or sequential bilobar regional liver therapy for patients with advanced disease to a versatile, potentially curative, and often highly selective local treatment for patients across Barcelona Clinic Liver Cancer stages. With this shift, radiation dosimetry has evolved to become more tailored to patients and target lesion(s), with treatment dose and distributions adapted for specific clinical goals (ie, palliation, bridging or downstaging to liver transplantation, converting to surgical resection candidacy, or ablative/curative intent). Data have confirmed that "personalizing" dosimetry yields real-world improvements in tumor response and overall survival while maintaining a favorable adverse event profile. In this review, imaging techniques used before, during, and after TARE have been reviewed. Historical algorithms and contemporary image-based dosimetry methods have been reviewed and compared. Finally, recent and upcoming developments in TARE methodologies and tools have been discussed.

Radioembolization for Intermediate-Stage Hepatocellular Carcinoma Maintains Liver Function and Permits Systemic Therapy at Progression.

PURPOSE: To assess the liver function trends in patients with intermediate-stage (Barcelona Clinic Liver Cancer [BCLC] Stage B) hepatocellular carcinoma (HCC) who underwent yttrium-90 transarterial radioembolization (TARE) in response to a growing concern that liver-directed therapies negatively affect liver function and prevent patients with HCC from systemic therapy candidacy. MATERIALS AND METHODS: An HCC/TARE database (2004-2017) was retrospectively reviewed. Patients with BCLC Stage B/Child-Pugh (CP)-A HCC with laboratory test and imaging data at baseline and for at least 1 month after TARE were included. Follow-ups were at 3-month intervals. CP stage was assessed at each time point. End points included time to persistent CP-B status, time to CP-C status, and median overall survival (OS). Time-to-end point analyses were performed using the Kaplan-Meier method. RESULTS: Seventy-four patients (80% men, with a mean age of 63 years) with mostly (62%) bilobar disease underwent 186 TARE treatments (median, 2; range, 1-8). The median time to second TARE was 2.3 months (range, 1.7-6.4 months), and the median times to third and fourth TAREs were 11.7 months (range, 7.5-15 months) and 17.3 months (range, 11.5-23.1 months), respectively. Forty-three (58%) patients developed persistent CP-B HCC at a median time of 15.4 months (95% CI, 9.2-25.3 months); 17 (23%) patients developed CP-C HCC at a median time of 87.2 months (95% CI, 39.8-136.1 months). The median OS censored to transplantation was 30.4 months (95% CI, 22.7-37.4 months). On univariate and multivariate analyses, baseline albumin was a significant prognosticator of OS, whereas baseline albumin and bilirubin were significant prognosticators of time to persistent CP-B HCC and time to CP-C HCC. CONCLUSIONS: In patients with CP-A HCC who underwent TARE for BCLC Stage B HCC, the median time to persistent CP-B HCC was 15.4 months. These findings indicate that patients would be candidates for systemic therapy at progression if indicated.

Yttrium-90 Radiation Segmentectomy in Oligometastatic Secondary Hepatic Malignancies.

PURPOSE: To evaluate the safety and efficacy of yttrium-90 (90Y) radiation segmentectomy (RS) in the treatment of oligometastatic secondary hepatic malignancies. MATERIALS AND METHODS: This institutional review board-approved retrospective study evaluated 16 patients with oligometastatic secondary hepatic malignancies who were treated with RS. The median patient age was 61.9 years (range, 38.6-85.7 years). Of the 16 patients, 11 (68.8%) presented with solitary lesions. The median index tumor size was 3.1 cm (95% CI, 2.3-3.9). Primary outcomes were evaluation of clinical and biochemical toxicities using National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0, and imaging response using Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary outcomes were time to progression (TTP) and overall survival (OS) as estimated by the Kaplan-Meier method. RESULTS: Clinical Grade 3 toxicities were limited to 1 (6.7%) patient who experienced fatigue, abdominal pain, nausea, and vomiting. Biochemical Grade 3 toxicities occurred in 1 (6.7%) patient who experienced lymphopenia. No Grade 4 clinical or biochemical toxicities were identified. Disease control was achieved in 14 (93.3%) of 15 patients. The median TTP of the treated tumor was 72.9 months (95% CI, 11.2 to no estimate). The median OS was 60.9 months (95% CI, 24.7 to no estimate). CONCLUSIONS: 90Y RS displayed an excellent safety profile and was effective in achieving a high disease control rate in the treatment of oligometastatic secondary hepatic malignancies.

Percutaneous Cystic Duct Interventions and Drain Internalization for Calculous Cholecystitis in Patients Ineligible for Surgery.

PURPOSE: To evaluate the feasibility, effectiveness, and outcomes of percutaneous cholecystostomy drain internalization in patients with calculous cholecystitis who were not surgical candidates. MATERIALS AND METHODS: Percutaneous cystic duct interventions were attempted in 17 patients (with the intent to place dual cholecystoduodenal stents) who were deemed unfit for surgery and had previously undergone percutaneous cholecystostomies for acute calculous cholecystitis. Baseline demographics, technical success, time from percutaneous cholecystostomy to internalization (dual cholecystoduodenal stent placement), stent patency duration, and adverse event rates were evaluated. RESULTS: Fifteen (88%) of 17 procedures to cross the cystic duct were technically successful. Of these 17 patients, 13 (76%) underwent successful placement of dual cholecystoduodenal stents. Two of these 13 patients (who had successful dual cholecystoduodenal stent placement) needed repeat percutaneous cholecystostomy drains (1 patient had stent migration leading to recurrent cholecystitis, and the other had a perihepatic biloma). The 1-year patency rate was 77% (95% CI, 47%-100%). CONCLUSIONS: Dual cholecystoduodenal stent placement in nonsurgical patients is a technically feasible treatment option with the goal to remove percutaneous cholecystostomy drains.

Defining textbook outcome for selective internal radiation therapy of hepatocellular carcinoma: an international expert study.

BACKGROUND: A textbook outcome (TO) is a composite indicator covering the entire intervention process in order to reflect the "ideal" intervention and be a surrogate for patient important outcomes. Selective internal radiation therapy (SIRT) is a complex multidisciplinary and multistep intervention facing the challenge of standardization. This expert opinion-based study aimed to define a TO for SIRT of hepatocellular carcinoma. METHODS: This study involved two steps: (1) the steering committee (4 interventional radiologists) first developed an extensive list of possible relevant items reflecting an optimal SIRT intervention based on a literature review and (2) then conducted an international and multidisciplinary survey which resulted in the final TO. This survey was online, from February to July 2021, and consisted three consecutive rounds with predefined settings. Experts were identified by contacting senior authors of randomized trials, large observational studies, or studies on quality improvement in SIRT. This study was strictly academic. RESULTS: A total of 50 items were included in the first round of the survey. A total of 29/40 experts (73%) responded, including 23 interventional radiologists (79%), three nuclear medicine physicians (10%), two hepatologists, and one oncologist, from 11 countries spanning three continents. The final TO consisted 11 parameters across six domains ("pre-intervention workup," "tumor targeting and dosimetry," "intervention," "post-90Y imaging," "length of hospital stay," and "complications"). Of these, all but one were applied in the institutions of > 80% of experts. CONCLUSIONS: This multidimensional indicator is a comprehensive standardization tool, suitable for routine care, clinical round, and research.

Clinical, dosimetric, and reporting considerations for Y-90 glass microspheres in hepatocellular carcinoma: updated 2022 recommendations from an international multidisciplinary working group.

PURPOSE: In light of recently published clinical reports and trials, the TheraSphere Global Dosimetry Steering Committee (DSC) reconvened to review new data and to update previously published clinical and dosimetric recommendations for the treatment of hepatocellular carcinoma (HCC). METHODS: The TheraSphere Global DSC is comprised of health care providers across multiple disciplines involved in the treatment of HCC with yttrium-90 (Y-90) glass microsphere-based transarterial radioembolization (TARE). Literature published between January 2019 and September 2021 was reviewed, discussed, and adjudicated by the Delphi method. Recommendations included in this updated document incorporate both the results of the literature review and the expert opinion and experience of members of the committee. RESULTS: Committee discussion and consensus led to the expansion of recommendations to apply to five common clinical scenarios in patients with HCC to support more individualized efficacious treatment with Y-90 glass microspheres. Existing clinical scenarios were updated to reflect recent developments in dosimetry approaches and broader treatment paradigms evolving for patients presenting with HCC. CONCLUSION: Updated consensus recommendations are provided to guide clinical and dosimetric approaches for the use of Y-90 glass microsphere TARE in HCC, accounting for disease presentation, tumor biology, and treatment intent.

Controversies in Prostate Artery Embolization: Future Best Practice.

Prevalence of lower urinary tract symptoms secondary to benign prostatic hyperplasia is correlated with age. Men seeking treatment options with a low side effect profile often turn to prostate artery embolization (PAE). PAE continues to be refined with advanced tools and optimized techniques. Nonetheless, there exist controversies in terms of best practices for the management of lower urinary track symptoms (LUTS) with PAE. These controversies are essential for medical progress. Herein we suggest best practices moving forward based on currently available data. Given extensive safety data, we recommend PAE be considered alongside medical management and as a precursor to surgery. Given demonstrated efficacy across gland sizes, PAE can be performed in a single session, ideally in a hybrid angio-CT suite, without preoperative cross-sectional imaging. PAE should be initially performed with 300- to 500-µm size particles, and instead consider exploring other particles and sizes for repeat PAE. Finally, PAE can also be considered as first-line option for recurrent disease given the efficacy and excellent safety profile. This article is not meant to purport a dogma, but rather to serve as a guide to the experienced practitioner in challenging his or her own biases when performing PAE.

What to do about hepatocellular carcinoma: Recommendations for health authorities from the International Liver Cancer Association.

Hepatocellular carcinoma (HCC) is a major public health problem worldwide for which the incidence and mortality are similar, pointing to the lack of effective treatment options. Knowing the different issues involved in the management of HCC, from risk factors to screening and management, is essential to improve the prognosis and quality of life of affected individuals. This document summarises the current state of knowledge and the unmet needs for all the different stakeholders in the care of liver cancer, meaning patients, relatives, physicians, regulatory agencies and health authorities so that optimal care can be delivered to patients. The document was commissioned by the International Liver Cancer Association and was reviewed by senior members, including two ex-presidents of the Association. This document lays out the recommended approaches to the societal management of HCC based on the economic status of a given region.

A Framework for Harmonization of Radiomics Data for Multicenter Studies and Clinical Trials.

PURPOSE: Variability in computed tomography images intrinsic to individual scanners limits the application of radiomics in clinical and research settings. The development of reproducible and generalizable radiomics-based models to assess lesions requires harmonization of data. The purpose of this study was to develop, test, and analyze the efficacy of a radiomics data harmonization model. MATERIALS AND METHODS: Radiomic features from biopsy-proven untreated hepatic metastasis (N = 380) acquired from 167 unique patients with pancreatic, colon, and breast cancers were analyzed. Radiomic features from volume-match 551 samples of normal liver tissue and 188 hepatic cysts were included as references. A novel linear mixed effect model was used to identify effects associated with lesion size, tissue type, and scanner model. Six separate machine learning models were then used to test the effectiveness of radiomic feature harmonization using multivariate analysis. RESULTS: Proposed model identifies and removes scanner-associated effects while preserving cancer-specific functional dependence of radiomic features on the tumor size. Data harmonization improves the performance of classification models by reducing the scanner-associated variability. For example, the multiclass logistic regression model, LogitBoost, demonstrated the improvement in sensitivity in the range from 15% to 40% for each type of liver metastasis, whereas the overall model accuracy and the kappa coefficient increased by 5% and 8% accordingly. CONCLUSION: The model removed scanner-associated effects while preserving cancer-specific functional dependence of radiomic features.

Promoting Surgical Resection through Future Liver Remnant Hypertrophy.

An inadequate future liver remnant (FLR) can preclude curative-intent surgical resection for patients with primary or secondary hepatic malignancies. For patients with normal baseline liver function and without risk factors, an FLR of 20% is needed to maintain postsurgical hepatic function. However, the FLR requirement is higher for patients who are exposed to systemic chemotherapy (FLR, >30%) or have cirrhosis (FLR, >40%). Interventional radiologic and surgical methods to achieve FLR hypertrophy are evolving, including portal vein ligation, portal vein embolization, radiation lobectomy, hepatic venous deprivation, and associating liver partition and portal vein ligation for staged hepatectomy. Each technique offers particular advantages and disadvantages. Knowledge of these procedures can help clinicians to choose the suitable technique for each patient. The authors review the techniques used to develop FLR hypertrophy, focusing on technical considerations, outcomes, and the advantages and disadvantages of each approach. Online supplemental material is available for this article. ©RSNA, 2022.

How Endoscopic Guidance Augments Nonvascular Image-guided Interventions.

Endoscopy can improve guidance in nonvascular procedures performed by interventional radiologists (IRs). Historically, the major limiting factors preventing the widespread use of endoscopic tools by IRs were the large diameter (>20F) and length of the endoscopes. IRs had to significantly upsize their access into vascular organs such as the kidney and liver to allow endoscope placement. With the advent of newer endoscopes with sizes smaller than 11F (approximately 4 mm in diameter), percutaneous endoscopy has become more feasible than before. IRs routinely place percutaneous drains (eg, abscess drains, biliary drains, percutaneous nephrostomies, and percutaneous cholecystostomies). Once the drain is in position and the acute infection (if present) has resolved, the IR can use the percutaneous access to perform image-guided and endoscopically guided procedures, depending on the clinical situation. Most percutaneous image- and endoscopically guided interventions performed by IRs involve procedures for biliary and gallbladder pathologic conditions. Image-guided procedures with additional endoscopic guidance can also be used to manage urinary, gastrointestinal, and gynecologic pathologic conditions. The authors review the current applications and techniques of percutaneous endoscopy in interventional radiology. In unique situations, IRs can also perform endoscopy through natural orifices (eg, the urethra) or surgically created orifices (eg, urostomies). The authors also discuss the adjunctive techniques that are enhanced or made possible because of endoscopy in interventional radiology, including but not limited to endoscopic forceps biopsies, endobiliary ablation, laser stricturotomy, lithotripsy, and stone extraction. An invited commentary by Srinivasa is available online. Online supplemental material is available for this article. ©RSNA, 2022.