CT Guidance Research Articles

Establishment of a Rat Model of Infraorbital Neuroinflammation Under CT Guidance.

The aim is to establish a rat model of infraorbital neuroinflammation with less trauma, stable pain, and a long duration of pain. The pathogenesis of trigeminal neuralgia (TN) is not fully clear. There are various models of TN in rats with different disadvantages, such as damaging the surrounding structures and inaccuracy of location for infraorbital nerve (ION). We aim to establish a rat model of infraorbital neuroinflammation with minimal trauma, a simple operation, and accurate positioning under CT guidance to help us study the pathogenesis of trigeminal neuralgia. Thirty-six adult male Sprague Dawley rats (180-220 g) were randomly divided into 2 groups and injected with talc suspension or saline through the infraorbital foramen (IOF) under CT guidance. Mechanical thresholds were measured in the right ION innervation region of 24 rats over 12 postoperative weeks. At 4 weeks, 8 weeks, and 12 weeks after the operation, the inflammatory involvement of the surgical area was evaluated by MRI, and neuropathy was observed using a transmission electron microscope (TEM). The talc group had a significant decrease in the mechanical threshold at 3 days after surgery that continued until 12 weeks post-operation, and the talc group had a significantly lower mechanical threshold than the saline group 10 weeks post-operation. The talc group had significantly impaired trigeminal nerve (TGN) myelin after 8 weeks post-operation. The rat model of infraorbital neuroinflammation established by CT-guided injection of talc into the IOF is a simple operation that results in less trauma, stable pain, and a long duration of pain. Moreover, infraorbital neuroinflammation in peripheral branches of the TGN can cause demyelination of the TGN in the intracranial segment.

Application of intraoperative CT-assisted positioning in difficult cases of cochlear implantation

Objective:To report the experience of using CT-guided cochlear implant surgery in difficult cases such as severe inner ear deformities and anatomical abnormalities, and to discuss the application value of intraoperative CT-assisted localization in difficult cases of cochlear implant surgery. Methods:Retrospectively analyzed the clinical data of 23 cases of difficult cochlear implant surgery cases completed by our team with the assistance of intraoperative CT, and collected their medical data, including preoperative imaging manifestations, surgical conditions, and intraoperative imaging images for evaluation. Results:During the study period, 23 difficult cases（27 ears） underwent cochlear implantation under the guidance of intraoperative CT, and 4 cases were bilaterally implanted. Including 6 cases of incomplete segmentation type Ⅰ（IP-Ⅰ）, 1 case of incomplete segmentation type Ⅱ（IP-Ⅱ）, 10 cases of incomplete segmentation type Ⅲ（IP-Ⅲ）, 3 cases of common cavity deformity（CC） and 3 cases of cochlear ossification after meningitis. Facial nerve anatomy was abnormal in 9 cases, cerebrospinal fluid "blowout" was serious in 14 cases, electrode position was abnormal in 3 cases requiring intraoperative adjustment of electrode position, anatomical difficulties required intraoperative CT to assist in finding anatomical landmarks in 2 cases, and electrodes were not fully implanted in 3 cases. Conclusion:When faced with difficult cases with challenging and complex temporal bone anatomy, intraoperative CT can accurately evaluate the electrode position and provide intraoperative anatomical details, allowing immediate adjustment of the electrode position if necessary, providing safety guarantee for difficult cases of cochlear implant surgery and ensure accurate implantation of electrodes.

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.

Robotic versus freehand CT-guided radiofrequency ablation of pulmonary metastases: a comparative cohort study

PurposeRadiofrequency ablation (RFA) is a curative treatment option for small lung metastases, which conventionally involves multiple freehand manipulations until the treating electrode is satisfactorily positioned. Stereotactic and robotic guidance has been gaining popularity for liver ablation, although has not been established in lung ablation. The purpose of this study is to determine the feasibility, safety, and accuracy of robotic RFA for pulmonary metastases, and compare procedures with a conventional freehand cohort.MethodsA single center study with prospective robotic cohort, and retrospective freehand cohort. RFA was performed under general anesthesia using high frequency jet ventilation and CT guidance. Main outcomes were (i) feasibility/technical success (ii) safety using Common Terminology Criteria for Adverse Events (iii) targeting accuracy (iv) number of needle manipulations for satisfactory ablation. Robotic and freehand cohorts were compared using Mann–Whitney U tests for continuous variables, and Fisher’s exact for categorical variables.ResultsThirty-nine patients (mean age 65 ± 13 years, 20 men) underwent ablation of 44 pulmonary metastases at single specialist cancer center between July 2019 and August 2022. 20 consecutive participants underwent robotic ablation, and 20 consecutive patients underwent freehand ablation. All 20/20 (100%) robotic procedures were technically successful, and none were converted to freehand procedures. There were 6/20 (30%) adverse events in the robotic cohort, and 15/20 (75%) in the freehand cohort (P = 0.01). Robotic placement was highly accurate with 6 mm tip-to-target distance (range 0–14 mm) despite out-of-plane approaches, with fewer manipulations than freehand placement (median 0 vs. 4.5 manipulations, P < 0.001 and 7/22, 32% vs. 22/22, 100%, P < 0.001).ConclusionsRobotic radiofrequency ablation of pulmonary metastases with general anesthesia and high frequency jet ventilation is feasible and safe. Targeting accuracy is high, and fewer needle/electrode manipulations are required to achieve a satisfactory position for ablation than freehand placement, with early indications of reduced complications.

α-Cyanoacrylate Rapid Medical Adhesive (Medical EC Glue) Localization of Pulmonary Nodules Guided by Computed Tomography before Thoracoscopic Surgery.

The study aims to conduct lung cancer screening by low-dose CT to identify the nature of the pulmonary nodule. The purpose of this study was to evaluate the role of preoperative medical EC glue localization of pulmonary nodules of uncertain nature by minimally invasive surgical resection. From December 2017 to December 2019, 18 patients (12 women, 6 men; median age: 54 years)with pulmonary nodules were located using medical EC glue under the guidance of preoperative CT and then resected under video thoracoscopy at Air Force Medical Center of PLA. The clinical characteristics were retrospectively collected to evaluate the effectiveness, safety and feasibility of the operation. The mean value of the maximum diameter of pulmonary nodules on CT images before the operation was 10.8 mm. The average depth was 10.3 mm (1.0-39.5 mm). Among 18 nodules, 8 were pure ground glass nodules, 3 were solid nodules, and 7 were partial solid nodules. The diagnosis rate of medical glue localization under the guidance of CT after the operation was 100%. Postoperative pathological diagnosis showed that there were 10 cases of primary lung adenocarcinoma, 1 case of invasive lung adenocarcinoma, 3 cases of adenocarcinoma in situ, 1 case of metastatic adenocarcinoma, and 3 cases of benign nodules. No obvious serious complications were found after localization. This study suggests that CT-guided percutaneous medical EC glue localization is a reliable, safe, feasible and practical method for undiagnosed pulmonary nodules and can significantly improve the rate of resection of small pulmonary nodules. Furthermore, it was considered to be more reasonable to remove pulmonary nodules and maximize the preservation of lung function.

Safety and efficacy of iodine-125 seed strand for intraluminal brachytherapy on ureteral carcinoma.

Our aim is to evaluate the safety and efficacy of iodine-125 seed strand for intraluminal brachytherapy on ureteral carcinoma. From November 2014 to November 2021, 22 patients with ureteral cancer not suitable for surgical resection were enrolled. Iodine-125 seed strand was inserted under c-arm CT and fluoroscopic guidance. The technical success rate, complications, disease control rate, and survival time were evaluated. Hydronephrosis Girignon grade and ureteral cancer sizes before and after treatment were compared. A total of 46 seed strands were successfully inserted and replaced, with a technical success rate of 100% and median procedure time of 62min. No procedure-related death, ureteral perforation, infection, or severe bleeding occurred. Minor complications were observed in eight (36.4%) patients, and migration of seed strand was the most common complication. Six months after seed strand brachytherapy, one complete response, three partial responses, and five stable diseases were evaluated, and the disease control rate was 64.3%. The Girignon grade of hydronephrosis was significantly improved 1 to 3 months after seed strand insertion. Disease control rates were 94.4, 62.5, and 64.3% at 1-, 3-, and 6-month follow-up. Twenty patients were successfully followed up, with a mean follow-up of 18.0 ± 14.5 months. The median overall survival and progress-free survival were 24.7 and 13.0 months, respectively. Iodine-125 seed strand is safe and effective for intraluminal brachytherapy and can be used as an alternative to patients with ureteral carcinoma who are not suitable for surgical resection or systemic combined therapy.

Dose variations for biopsy, puncture and drainage under CT guidance: A national survey in 1709 patients.

A nation-wide study recently published the dose reference levels for the main CT-guided interventional procedures in 5001 patients. We assessed the impact of patient's age, sex and targeted organ on the patient dose during thoracic and abdominopelvic biopsies and punctures/drainages. Data were extracted from the previous nationwide study. All biopsies, punctures and drainages for thoracic or abdominopelvic locations performed between January 2017 and June 2019 in all participating centers were included in the study. Multivariable analyses were carried out using a linear regression of the dose-length product (DLP) log, adjusted to age, sex, anatomical location, number of helical acquisitions and inclusion center. Of the 5001 patients of the initial study, 2383 benefited from thoracic or abdominopelvic procedures, including 674 percutaneous destructions excluded. 1709 patients (44 centers), 1045 men, 664 women, median age 64.4±14.0 years were included. The mean DLP was 751.2±642.7mGy.cm. It was significantly higher in men than women (p=0.0005) and higher for abdominopelvic procedures than for thoracic locations (p<0.0001). Doses delivered to patients for abdominal and thoracic biopsies and punctures/drainages performed under CT guidance depend on gender and location. Furthers studies taking into account the patient's morphology and anatomical location of the procedure would allow proposing finer dose reference levels.

Abstract No. 158 Characterizing the Anti-Tumor Immune Response to IRE vs Thermal Ablation Therapy in an Immunocompetent Oncopig Model of Hepatocellular Carcinoma

Immunotherapies for cancer treatment are designed to mobilize a patient’s own immune system against their malignancy locally and systemically. Percutaneous ablation techniques have the potential to work in conjunction with modern immunotherapies by priming the patient’s own lymphocytes to attack previously untreated cancer cells. This phenomenon, known as the abscopal effect, has garnered interest because of the potential for locoregional therapies to induce local and systemic anti-tumor effects and shrinkage of distant tumors (Fionda, 2020). The goal of this study is to evaluate the anti-tumor immune response to irreversible electroporation (IRE) compared with microwave (MWA) and cryoablation in an immunocompetent Oncopig liver tumor model of hepatocellular carcinoma. In-situ liver tumors were induced in a transgenic immunocompetent porcine liver model (2-4 tumors in each liver) with Cre-recombinase induced TP53 and KRAS mutations (Oncopig). Oncopigs were separated into three treatment groups (n = 2), each undergoing either MWA, cryoablation or IRE treatment of a single liver tumor under US or CT guidance. Pre-, immediate post- and 1-week post ablation imaging was performed to evaluate treated and non-treated tumor growth. At each time point, venous blood was also drawn and assayed for critical cytokines related to anti- or pro-tumor immune response. Systemic cytokine levels were correlated to targeted and off-targeted tumor volumes after each time point. Liver tumors were induced at an 83.3% (20/24) success rate. Treated tumors decreased by an average 7% in volume across all treatment modalities on 1-week follow-up imaging. Off-target tumors increased by volume by 71.7% with IRE, 13.6% with MWA and 1.4% with cryoablation. On 1-week blood samples, IRE treated pigs demonstrated lower circulating concentrations of pro-inflammatory IL-2 cytokines when compared with cryoablation (10.9 vs 40.7 pg/mL; P = 0.051). There was no difference in IL-2 levels between MWA and cryoablation-treated pigs (40.7 vs 42.4 pg/mL; P = 0.97). The pro- and anti-tumor immune response is dependent on the type of ablation modality. IRE had the lowest levels of inflammatory marker IL-2 and the lowest degree of tumor control in off target tumors at the one-week time point. Modulating inflammatory pathways via these cytokines after IRE may potentially play a role in amplifying the abscopal effect in liver tumors.

Establishment of a rabbit liver metastasis model by percutaneous puncture of the spleen and implantation of the VX2 tumor strain under CT guidance

This study aimed to compare the feasibility, success rate, and safety of establishing a rabbit VX2 liver metastasis model by percutaneous splenic implantation under CT guidance and open splenic implantation of the VX2 tumor strain. Fifty-two New Zealand white rabbits were randomly divided into group A (the percutaneous puncture group) (n = 26) and group B (the laparotomy group) (n = 26). In group A, 26 New Zealand white rabbits were implanted with tumor strains by percutaneous splenic puncture under CT guidance. In group B, 26 New Zealand white rabbits were implanted with tumor strains in the spleen by laparotomy. After 2–3 weeks of implantation, both group A and group B underwent MRI to confirm tumor growth in the spleen and metastasis to the liver. Two experimental rabbits randomly selected from groups A and B were killed for pathological examination. The success rate, complication rate, and operation time in groups A and B were compared and analyzed. A total of 23 rabbits in group A were successfully induced, and the success rate was 88.5% (23/26). The average time of operation was 14.42 ± 3.26 min. A total of 22 rabbits in group B were successfully induced, and the success rate was 84.6% (22/26). The average time of operation in group B was 23.69 ± 5.27 min. There was no significant difference in the success rate of induction between the two groups (P > 0.05). The MRI manifestations of liver metastases were multiple nodular and punctate abnormal signal shadows in the liver. Hematoxylin–eosin (HE) staining showed a large number of tumor cells in the tumor area. CT-guided percutaneous splenic implantation of the VX2 tumor strain to establish a rabbit liver metastasis model is a minimally invasive and feasible inducing method. The success rate of this technique is not lower than that of open splenic implantation, with low incidence of complications, and short operation time.

Image-Guided Biopsy in Acute Diskitis-Osteomyelitis: A Systematic Review and Meta-Analysis.

BACKGROUND. The reported sensitivity and yield of image-guided biopsies for diskitis-osteomyelitis vary widely. OBJECTIVE. The purpose of this study was to perform a systematic review of the literature and meta-analysis of pooled sensitivity data to elucidate strategies for optimal image-guided biopsies among patients suspected to have diskitis-osteomyelitis. EVIDENCE ACQUISITION. A comprehensive literature search was performed for studies of patient populations with proven or suspected diskitis-osteomyelitis that included percutaneous image-guided biopsy as part of the workup algorithm. Type of pathogens, imaging modality used for biopsy guidance, tissue targeted, antibiotic administration at the time of biopsy, true microbiology positives, true microbiology negatives, false microbiology positives, false microbiology negatives, disease (i.e., diskitis-osteomyelitis) positives as determined by reference standard, true infection positives (i.e., positive microbiology or pathology results), and total number of biopsies performed were extracted from the studies. Microbiology sensitivity, microbiology biopsy yield, and infection sensitivity were calculated from the pooled data. These terms and the data required to calculate them were also defined in detail. EVIDENCE SYNTHESIS. Thirty-six articles satisfied inclusion criteria and were used for analysis. The pooled microbiology sensitivity, infection sensitivity, and microbiology biopsy yields were 46.6%, 70.0%, and 26.7%, respectively. Mycobacterium tuberculosis-only microbiology sensitivity was significantly higher than both pyogenic bacteria and mixed-organism microbiology sensitivity (p < .001). Staphylococcus aureus was the most common causative organism (28.6%). Pooled microbiology sensitivity was not significantly different for CT guidance and fluoroscopy guidance (p = .16). There was a statistically significant difference between pooled microbiology sensitivity of bone/end plate (45.5%) and disk/paravertebral soft-tissue (64.8%) image-guided biopsies (p < .001). There was no statistically significant difference in pooled microbiology sensitivities for patients who received antibiotics before the procedure (46.2%) and those who did not (44.6%) (p = .70). CONCLUSION. Image guidance by CT or fluoroscopy does not affect microbiology yield, disk and paravertebral soft-tissue biopsies should be considered over bone and end plate biopsies, and preprocedural antibiotic administration does not appear to impact biopsy results. CLINICAL IMPACT. Understanding and correctly applying reported statistics contribute to appropriate interpretation of the abundant literature on this topic and optimization of care for patients with diskitis-osteomyelitis.

Evaluation of Accuracy and Performance of a Novel, Fully Gantry Integrated 3D Laser System for Computed Tomography Guided Needle Placement: A Phantom Study.

The purpose of this phantom study was to compare the accuracy, speed and technical performance of CT guided needle placement using a conventional technique versus a novel, gantry integrated laser guidance system for both an expert and a novice. A total of 80 needle placements were performed in an abdominal phantom using conventional CT guidance and a laser guidance system. Analysis of pooled results of expert and novice showed a significant reduction of time (277 vs. 204 s, p = 0.001) and of the number of needle corrections (3.28 vs. 1.58, p < 0.001) required when using laser guidance versus conventional technique. No significant improvement in absolute (3.81 vs. 3.41 mm, p = 0.213) or angular deviation (2.85 vs. 2.18°, p = 0.079) was found. With either approach, the expert was significantly faster (conventional guidance: 207 s vs. 346 s, p < 0.001; laser guidance: 144 s vs. 264 s, p < 0.001) and required fewer needle corrections (conventional guidance: 4 vs. 3, p = 0.027; laser guidance: 2 vs. 1, p = 0.001) than the novice. The laser guidance system helped both the expert and the novice to perform CT guided interventions in a phantom faster and with fewer needle corrections compared to the conventional technique, while achieving similar accuracy.

Combination of image-guided IMRT and IGBT in locally advanced carcinoma cervix: Prospective evaluation of toxicities and clinical outcomes from a tertiary cancer center in India.

We aimed to assess the toxicity profile and clinical outcome in patients with locally advanced cervical cancer (LACC) treated with a combination of image-guided intensity-modulated radiation therapy (IG-IMRT) and image-guided brachytherapy (IGBT). 25 LACC patients were recruited in this single-arm prospective study. Whole pelvis IG-IMRT was delivered (45 Gy with simultaneously integrated nodal boost of 55 Gy in 25 fractions), with concurrent weekly cisplatin (40 mg/m2). Patients received IGBT of 7 Gy each in 4 fractions to high-risk clinical target volume (HR-CTV). First fraction was done under MRI, and subsequent fractions were performed under CT guidance. Primary endpoint was acute toxicity, and secondary endpoints were 2-year loco-regional control and late toxicity. The median age was 52 years, and FIGO 2018 stage distribution was IIA2, IIB, IIIB, and IIIC1 in 12%, 40%, 20%, and 28% patients, respectively. All patients received concurrent chemotherapy with median number of 5 cycles (range, 4-5 cycles). Grade 1 and 2 diarrhea, and grade 1 cystitis was reported in 4 (16%), 3 (12%), and 2 (8%) patients, respectively. Grade 1 and 2 anemia, and grade 1 and 2 dermatitis were observed in 3 (12%) and 2 (8%), and 3 (12%) and 3 (12%) patients, respectively. No patient reported grade 3-4 acute toxicity. At median follow-up of 29.5 months (range, 25-37 months), late grade 1 bladder toxicity was observed in 1 (4%) patient. Loco-regional control at 1 and 2 years were 96% and 92%, respectively. The combination of IG-IMRT and IGBT yielded excellent outcomes in terms of acute toxicity and loco-regional control.

Benefit Over Risk Assessment of CT-guided Lung Core Needle Biopsy With the Coaxial Technique.

Lung percutaneous needle biopsy (PNB) under CT guidance can be performed with a single-needle or with a coaxial (CX) technique. This study evaluated the CX technique in a large cohort of patients who underwent to CT-guided lung PNB in our Institute over a period of 7 years. We retrospectively collected and analyzed data relative to 700 CT-guided lung PNBs performed from August 2012 to August 2019 in 700 patients (M:F=436:264; mean age=69 years, range=6-93 years) with normal coagulation and pulmonary function. PNB was considered diagnostic if at least one of the collected tissue specimens allowed for histological diagnosis. Pulmonary hemorrhage (PH) and pneumothorax (PNX) were evaluated as present or absent. Statistical analysis was made by Chi-square test of Pearson, Fisher's exact test and Wilcoxon test. The CX technique showed a high diagnostic accuracy (93.0%) and allowed the collection of a great number of appropriate tissue specimens with a single pleural puncture (≥3 specimens in 77.4% of cases). PH was the complication more frequent (55.4%), without significant clinical impact. Global PNXs incidence was high (42.9%), but the introducer allowed to aspirate the PNX with a lower percentage of chest tube placement vs. PNXs not aspirated (6.3% and 13.3%, respectively). This large retrospective study confirmed the high diagnostic accuracy of lung PNB with the CX technique and allowed identification of significant factors to achieve a greater diagnostic power and decrease complication rates.

8 Hybrid intracavitary and interstitial brachytherapy for cervical cancer in the outpatient setting

Image-guided hybrid intracavitary and interstitial brachytherapy (HBT) for the treatment of locally advanced cervical cancer may improve outcomes compared to intracavitary brachytherapy alone. Pain control is usually achieved with general anesthesia (GA), which increases both treatment duration and the risk of complications with each treatment. Here we detail the results of our institution's protocol with CT-guided interstitial needle placement, utilizing minimal sedation. A single-institutional database of patients who underwent HBT for cervical cancer from June 2018 to May 2020 was queried. Patterns of anesthesia usage, step-by-step procedural times, medication usage, and treatment-related complications were reviewed. All patients had a Smit sleeve placed in the OR under GA days before their first HBT treatment. Prior to HBT, patients received minimal sedation, composed of oral lorazepam and hydrocodone/acetaminophen. Tandem and ovoids were inserted and interstitial needles were placed under CT guidance. The patients were moved from the CT table to a surgical bed, and then to the radiation vault for treatment delivery. The applicator was then removed and vaginal packing was inserted if any bleeding occurred. A total of 244 implants were placed in 63 patients under minimal sedation. 61 patients (96.8%) tolerated the procedure, 2 (3.2%) required epidural anesthesia, and 0 required transition to GA. The median time for the entire procedure (CT room entry to exit of the HDR room) was 70.0 mins (mean 70.3 mins, range 54–100 mins). The median time for the interstitial needle insertion portion was 9.0 mins (mean 9.8 mins, range 4–24 mins). Bleeding occurred in 54 (22.1%) implants, which resolved after 3 minutes of vaginal packing (mean 3.33 mins, range 1–8 mins). Our outpatient HBT protocol was efficient and well-tolerated, with reasonable bleeding rates which were minimal and quickly resolved. HBT with minimal sedation was achievable at a high percentage (96.8%). The performance of HBT without GA may reduce treatment time, costs, and anesthesia-related adverse effects. Treatment with minimal sedation has the potential to enable more universal use of HBT, improve brachytherapy dosimetry, and enhance patient outcomes. Further investigation is warranted.

Accuracy of CT-Guided Core-Needle Biopsy in Diagnosis of Thoracic Lesions Suspicious for Primitive Malignancy of the Lung: A Five-Year Retrospective Analysis.

Lung cancer represents a heterogeneous group of neoplasms, with the highest frequency and mortality in both sexes combined. In a clinical scenario characterized by the widespread of multidetector-row spiral CT, core-needle biopsy under tomographic guidance is one of the main and safest methods to obtain tissue specimens, even though there are relatively high rates of pneumothorax (0-60% incidence) and pulmonary hemorrhage (4-27% occurrence rates). The aim of this retrospective study is to assess the diagnostic accuracy of CT-guided core-needle biopsy in the diagnosis of primary lung malignancies and to compare our results with evidence from the literature. Our analysis included 350 thoracic biopsies, performed from 2017 to 2022 with a 64-row CT guidance and 16/18 G needles mounted on a biopsy gun. We included in the final cohort all samples with evidence of primary lung malignancies, precursor lesions, and atypia, as well as inconclusive and negative diagnoses. There was sensitivity of 90.07% (95% CI 86.05-93.25%), accuracy of 98.87% (95% CI 98.12-99.69%), positive predictive value of 100%, and negative value of 98.74% (95% CI 98.23-99.10%). Specificity settled at 100% (93.84-100%). The AUC was 0.952 (95% CI 0.924-0.972). Only three patients experienced major complications after the procedure. Among minor complications, longer distances from the pleura, the presence of emphysema, and the lower dimensions of the lesions were correlated with the development of pneumothorax after the procedure, while longer distances from the pleura and the lower dimensions of the lesions were correlated with intra-alveolar hemorrhage. Immunohistochemistry analysis was performed in 51% of true positive cases, showing TTF-1, CK7, and p40 expression, respectively, in 26%, 24%, and 10% of analyzed samples. The CT-guided thoracic core-needle biopsy is an extremely accurate and safe diagnostic procedure for the histological diagnosis of lung cancer, a first-level interventional radiology exam for peripheral and subpleural lesions of the lung, which is also able to provide adequate samples for advanced pathologic assays (e.g., FISH, PCR) to assess molecular activity and genetic sequencing.

Bone Marrow Biopsy, Does CT Guidance Add Value?

Background: Bone marrow aspirate and biopsies (BMAB) remain a corner stone in the diagnosis and management of various hematologic disorders. Specialized testing, such as cytogenetics, immunophenotypic and molecular analysis performed on these specimens, plays a crucial role in diagnosis and staging of Leukemias/Lymphomas, as well as in finding out molecular targets for potential therapeutic benefits. Thus, inadequate, and poor-quality specimens can limit making a precise diagnosis and providing optimal treatment. At our institution, we recognized that a substantial number of non-CT guided BMAB were being reported as suboptimal, although diagnosis was being made. Also, recently more CT guided (CTG) BMAB are being implemented. A drawback with CTG BMAB is scheduling delays, that can potentially result in treatment delays, and fatal outcomes especially in conditions like Acute Leukemias. Additionally, there is concern of higher cost associated with CT guided BMAB. Therefore, we performed a retrospective analysis on BMAB procedures performed at our institution between January 2019 and April 2022. Purpose:Evaluate and compare the quality of BMAB procedures performed with and without CT guidance (blind procedure) at our institution, and their respective waiting times.Identify potential areas for improvement.Provide data to help guide in choosing the most appropriate procedure. Methods: We retrospectively reviewed all adult BMAB procedures performed at our institution between January 2019 and April 2022, including patient demographics. Pathology reports were reviewed for adequacy of aspirate smears and core biopsies. Samples were deemed inadequate even if one of bone marrow aspirate or core or clot specimens were described by the pathologist as "suboptimal", "inadequate", "fragmented", "crushed", "hemodiluted", "no spicules", or "scant". Waiting period for the procedure was defined as the duration of time (in days) from the date of placing an order for biopsy (CTG or blind) to the date of procedure. CTG BMAB are typically performed by intervention radiologists (IR) while bind BMAB are usually performed by Oncologists (Fellows or attendings) at our institutions. Results: A total of 469 posterior iliac crest bone marrow aspirate and biopsy procedures were performed. More patients underwent BMAB procedure under CT guidance (61% vs 39% for non-CTG). More CTG BMAB samples were categorized as adequate (69%), compared to the non CTG (55%), (p=0.02). No statistical difference was noted in patient's age (p=0.639) or gender (p=.22) or Body mass index (BMI) (p=2.05) of CTG and non CTG groups (see table). The mean waiting period was longer for CTG procedure (27 days +/- 20 (0-135), compared to non CTG (15 days +/- 17 (0-105) (p=0.031). Although our pathologist described a sample as "suboptimal", a definitive diagnosis was still able to be made in all cases using the available bone marrow clot, aspirate and core specimens. Conclusion/Interventions: CTG BMAB procedures were more likely to result in adequate samples when compared to non-CTG procedures, however with longer waiting period and higher costs. So, we propose that obtaining non-CTG BMAB will improve cost effectiveness and reduce the wait times. To improve the adequacy of non CTG BMAB, we propose some interventions: 1. Provide an organized training during fellowship that includes theory followed by simulation, and practice-based training under supervision. 2. Discuss ICSH (International Council for Standardization in Hematology) guidelines for bone marrow adequacy criteria with the providers. For example, the length of a core biopsy from an adult should be at least 2cm. As our study suggests significant scheduling delays with CTG BMAB, such orders when requested, may be considered as urgent procedures to avoid potential treatment delays and poor outcomes. Alternately, when an aggressive hematologic disorder like acute leukemia is suspected, blind approach may be undertaken for prompt diagnosis. Interestingly, BMI was not significantly different in the two groups. However, if locating physical landmarks is impaired by body habitus, then CT guided BMAB should be strongly considered. We would like to highlight the importance of having adequate personnel including nurse navigators, technicians who play a vital role in obtaining timely insurance clearance, and procedure scheduling. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

MSS11 Presentation Time: 4:35 PM: Evaluation of Autocontouring in the Interstitial HDR Brachytherapy of Liver Tumors

<h3>Purpose</h3> The use of artificial intelligence (AI) in radiation therapy has been increased in the last years. The aim of this work is to investigate the use of AI in contouring during the interstitial HDR brachytherapy of the primary and secondary liver tumors. <h3>Materials and Methods</h3> 25 patients with 37 hepatic lesions of histologically confirmed primary and secondary liver tumors. The Liver tumors were treated by single fractioninterstitial HDR brachytherapy. The Brachytherapy Applicators were implanted into the tumor regions under CT guidance. Subsequently, a Planning CT with contrast medium and a slice thickness of 1.25 mm was performed. Retrospectively, the organs at risk (OAR) were assessed by an experienced Radiation Oncologist, as well as using AI by the autocontouring software Limbus Contour v.1.5.0. Here the calculations were performed once by the CPU (Central Processing Unit) and once by the GPU (Graphics Processing Unit). A PC with the Intel® Xeon® E5-2620V3 processor (CPU), 2.40 GHz, was used, as well as a graphics card (GPU) NVIDIA Quadro K620, 2GB GDDR3. The following organs at risk contoured: Liver, kidneys, stomach, intestine, heart, esophagus, and lungs. The time required for time required to contour the organs at risk was compared. <h3>Results</h3> The types of Tumor were illestrated in Figure 1. For the experienced radiation oncologist, the mean±standard deviation was 17.08±0.61 minutes. The software required a mean of 3.71±0.45 minutes for the CPU calculations. When using the GPU, the calculation time was only 2.24±0.23 minutes. The contouring times differed significantly (p <0.001). In 21 metastases, the contouring of Stomach was required, in 26 metastases required contouring of the right kidney, and in 33 metastases the contouring of intestine was required. <h3>Conclusions</h3> The application of artificial intelligence to interstitial HDR brachytherapy of the liver brachytherapy can shorten the treatment by about 15 minutes on average. This reduces the unpleasant lying time with applicators for the patient.

Contribution of Stereotaxic Biopsy in the Management of Brain Tumors: About 101 Cases

Introduction: The advent of Stereotaxic Biopsy (STB) and the development of CT and MRI have improved the management of brain tumours. The aim of this study is to evaluate the role of STB in the management of brain tumors. Material and Methods: Retrospective study from 2000 to 2020 concerning 101 consecutive patients with brain tumours, having benefited from a STB, collected in the neurosurgery departments of the the public hospital establishment of AIT IDDIR and Mustapha and Mustapha BACHA university hospital center. The seat of the lesion is deep or functional (the Rolondic region, hemispherical, basal ganglia, lateral ventricles and brainstem and pineal region). STB was performed under CT guidance in all cases. For pineal tumours, arteriography with venographic time and preoperative MRI has been deemed useful to avoid hemorrhagic complications. Results: In 101 cases, the STB was conclusive on the first attempt (90%). The repetition of the STB made it possible to re-establish a precise diagnosis in (5.94%) It was malignant lesions (70% of the cases). The average age of the patients was 46 years (3 to 72) with a male predominance. The topography of the lesions is: 75.13% in the Rolondic region, Central Gray Nuclei, Brainstem and pineal region; 12.87% in the corpus callosum and lateral ventricles and 12.5% in the eloquent superficial lesion. Postoperative complications are dominated by mortality 5.9% followed by partial epileptic seizure 2.98% and severe neurological disorders 1.98%, bilateral ptosis 1.98% and hemiplegia 0.99%. Perioperative mortality fell from 10.45% before 2005 to 1% after 2006 (Chi-square; p = 0.010). Conclusion: STBs should be staged and repeated in case of inconclusive histology. For small deep lesions STB under MRI conditions is necessary. For pineal tumours, it must be performed by the transtemporal orthogonal approach.

Multi-Institutional Comparison of Ablative Radiation Therapy in 5 Versus 15-25 Fractions for Locally Advanced Pancreatic Cancer

<h3>Purpose/Objective(s)</h3> Ablative RT doses ∼100Gy BED₁₀ are associated with improved overall survival (OS) in patients with locally advanced unresectable pancreatic cancer (LAPC), but the optimal fractionation scheme remains unknown. <h3>Materials/Methods</h3> We performed a retrospective analysis of consecutive LAPC patients treated at 2 high-volume institutions with either 50 Gy in 5 fractions using a 0.35T MR Linac and online adaptive replanning between 2018-2021 or 67.5-75 Gy in 15-25 fractions using CBCT guidance and selective offline adaptive replanning between 2016-2019. All were treated with breath hold or gating. Elective nodal coverage was used in 94%. Clinical characteristics between the groups were compared using Fisher's exact test. Freedom from local progression (FFLP) by RECIST and OS were estimated from time of RT with the Kaplan-Meier method. Log-rank test and Cox proportional hazards regression model were used for univariate (UVA) and multivariate (MVA) analyses. <h3>Results</h3> 183 patients were evaluated including 62 (34%) treated with 50 Gy in 5 fractions, 23 (123%) treated with 67.5 Gy in 15 fractions, and 98 (54%) treated with 75 Gy in 25 fractions. Median age was 67 years (range 35 to 91), 53% were male, 72% had a head tumor location, 81% were T3/4 with a median tumor size of 3.8 cm (range 1.4-7.4 cm) and 38% were lymph node positive. Patients receiving 5 fractions were more likely to be N0 than patients receiving 15-25 fractions (69.3% vs 44.6%, p=0.0219), and there were no other clinical differences between the groups. 98% received induction chemotherapy for a median of 3.9 months (FOLFIRINOX 61%, Gemcitabine/Nab-paclitaxel 29%, other 10%). Median follow-up was 38 months. Median FFLP and OS were 31 and 18 months, with 2-yr FFLP and 2-yr OS of 62.9% (95%CI 47.9 – 69.3%) and 36.2% (26.0 – 40.9%), respectively. There were no significant differences in FFLP (HR= 1.493, 95%CI 0.8030 – 2.775, p=0.1598) or OS (HR=1.321, 95%CI 0.8835 – 1.974, p=0.1580) between patients receiving 5 vs 15-25 fractions, respectively, on UVA. Likewise, after adjusting for T stage, nodal status, tumor size, chemotherapy type and duration, there were no significant differences in OS between the groups on MVA (HR=1.234, 95%CI 0.8151 – 1.833, p=0.3070). The rate of grade 3+ GI bleeding was 4.8% and 8% (p=0.5476) in patients receiving 5 vs 15-25 fractions, respectively. <h3>Conclusion</h3> In appropriately selected LAPC patients, ablative RT (BED₁₀ ∼100 Gy) in 5 fractions delivered with MR guidance and online adaptive replanning or 15-25 fractions delivered with CT guidance and selective offline adaptive replanning both appear to achieve excellent efficacy and minimal severe toxicity. Choice of fractionation scheme should be based on anatomical considerations and available technology.

Friday, June 17, 20223:30 PM - 3:45 PMPO12: Time Investment and Planning Benefit of Serial Treatment Planning MRI Scans for HDR Intracavitary Brachytherapy for Cervix Cancer

<h3>Purpose</h3> To estimate the time investment and planning benefit of acquiring treatment planning MRI scans for each insertion for tandem and ring (T&R) cases. <h3>Materials and Methods</h3> Fourteen (14) consecutive cervical cancer patients who underwent intracavitary HDR brachytherapy with T&R applicator were retrospectively analyzed. All patients received 28Gy in 4 fractions delivered in 2 insertions (Ins1 and Ins2), with 2 fractions per insertion, after completion of EBRT. All insertions were performed under general anesthesia with intraoperative CT and MRI guidance. Target (Cx) and normal tissues were contoured on each MRI scan at the time of the procedure. Four patients who did not have both insertions using MRI planning were excluded. Image registration of Ins2 to Ins1 was retrospectively performed in Eclipse (Varian Medical Systems, Palo Alto, CA) based on applicator position. Target contour from Ins2 (Cx2) was copied to the Ins1 structure set (Cx2reg) using this registration. The following metrics were recorded: volume of Cx1, Cx2, and dice similarity coefficient of the two [DSC = 2*(volCx1+volCx2)/(overlap between Cx1 and Cx2reg)] (0 indicates no overlap between the contours; 1 indicates perfect overlap). Target D90 using MRI for each insertion (D90 Cx1 on plan of Ins1 + D90 Cx2 on plan of Ins2) and using only Ins1 MRI (D90 Cx1 on plan of Ins1 + D90 Cx2reg on plan of Ins1). One patient had a replan for the second fraction of the first insertion was therefore excluded from the D90 analysis. Additional time required for MRI-based planning was calculated using the timestamps of the last in-room CT and of the T2 MRI. <h3>Results</h3> Cx1 and Cx2 volumes [median, interquartile range (IQR)] were 26.0 cm³ (IQR 11.3 cm³) and 22.9 cm³(IQR 16.7 cm³). DSC was 0.73 (IQR 0.05). Target D90 (as % of prescription dose) using MRI for each insertion vs. using only Ins1 MRI information for Ins2 was 109.6% (IQR 4.8%) vs. 110.1% (IQR 7.5%). Additional time for MRI-based planning was 38.8 minutes (IQR 6.3 minutes). <h3>Conclusions</h3> The addition of an MRI for Ins2 added only modest alterations in the target volume and D90, however, did add approximately 40 minutes of added time under anesthesia. The projected target coverage if Cx1 was used in insertion 2 instead of Cx2 would be sufficient and could be more efficient in terms of scan and, potentially, contouring time. This study supports the hypothesis that the time commitment required for MRI acquisition for Ins2 may not be justified by a planning advantage. Limiting factors of this study: contouring and fusion uncertainties; our methods did not consider changes in organs-at-risk between insertions; limited number of patients.