Image-guided Procedures Research Articles

Regional perception and multi-scale feature fusion network for cardiac segmentation

Objective. Cardiovascular disease (CVD) is a group of diseases affecting cardiac and blood vessels, and short-axis cardiac magnetic resonance (CMR) images are considered the gold standard for the diagnosis and assessment of CVD. In CMR images, accurate segmentation of cardiac structures (e.g. left ventricle) assists in the parametric quantification of cardiac function. However, the dynamic beating of the heart renders the location of the heart with respect to other tissues difficult to resolve, and the myocardium and its surrounding tissues are similar in grayscale. This makes it challenging to accurately segment the cardiac images. Our goal is to develop a more accurate CMR image segmentation approach. Approach. In this study, we propose a regional perception and multi-scale feature fusion network (RMFNet) for CMR image segmentation. We design two regional perception modules, a window selection transformer (WST) module and a grid extraction transformer (GET) module. The WST module introduces a window selection block to adaptively select the window of interest to perceive information, and a windowed transformer block to enhance global information extraction within each feature window. The WST module enhances the network performance by improving the window of interest. The GET module grids the feature maps to decrease the redundant information in the feature maps and enhances the extraction of latent feature information of the network. The RMFNet further introduces a novel multi-scale feature extraction module to improve the ability to retain detailed information. Main results. The RMFNet is validated with experiments on three cardiac data sets. The results show that the RMFNet outperforms other advanced methods in overall performance. The RMFNet is further validated for generalizability on a multi-organ data set. The results also show that the RMFNet surpasses other comparison methods. Significance. Accurate medical image segmentation can reduce the stress of radiologists and play an important role in image-guided clinical procedures.

Interventional Pain Procedures: A Narrative Review Focusing on Safety and Complications. Part 1 Injections for Spinal Pain.

In recent years, there has been a considerable increase in the number of image-guided interventional procedures performed for the management of acute and chronic pain. Concomitantly, there has also been an increase in the complication rate related to these procedures. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopic- or ultrasound-guided) interventional procedures. We conclude that although complications from interventional pain procedures can be mitigated to a certain degree, they cannot be eliminated altogether. In order to avoid adverse events, patient safety should be given considerable attention and physicians should be constantly aware of the possibility of developing complications.

A comparison of perceived image quality between computer display monitors and augmented reality smart glasses

IntroductionAugmented-reality (AR) smart glasses provide an alternative to standard computer display monitors (CDM). AR smart glasses may provide an opportunity to improve visualisation during fluoroscopy and interventional radiology (IR) procedures when there can be difficulty in viewing intra-procedural images on a CDM. The aim of this study was to evaluate radiographer perception of image quality (IQ) when comparing CDM and AR smart glasses. Methods38 radiographers attending an international congress evaluated ten fluoroscopic-guided surgery and IR images on both a CDM (1920 × 1200 pixels) and a set of Epson Moverio BT-40 AR smart glasses (1920 × 1080 pixels). Participants provided oral responses to pre-defined IQ questions generated by study researchers. Summative IQ scores for each participant/image were compared between CDM and AR smart glasses. ResultsOf the 38 participants, the mean age was 39 ± 1 years. 23 (60.5%) participants required corrective glasses. In terms of generalisability, participants were from 12 different countries, the majority (n = 9, 23.7%) from the United Kingdom. For eight out of ten images, the AR smart glasses demonstrated a statistically significant increase in perceived IQ (median [IQR] 2.0 [-1.0 to 7.0] points) when compared to the CDM. ConclusionAR smart glasses appear to show improvements in perceived IQ when compared to a CDM. AR smart glasses could provide an option for improving the experiences of radiographers involved in image-guided procedures and should be subject to further clinical evaluations. Implications for practiceOpportunities exist to improve perceived IQ for radiographers when reviewing fluoroscopy and IR images. AR smart glasses should be further evaluated as a potential opportunity to improve practice when visual attention is split between positioning equipment and image review.

Toward reliable calcification detection: calibration of uncertainty in object detection from coronary optical coherence tomography images.

Optical coherence tomography (OCT) has become increasingly essential in assisting the treatment of coronary artery disease (CAD). However, unidentified calcified regions within a narrowed artery could impair the outcome of the treatment. Fast and objective identification is paramount to automatically procuring accurate readings on calcifications within the artery. We aim to rapidly identify calcification in coronary OCT images using a bounding box and reduce the prediction bias in automated prediction models. We first adopt a deep learning-based object detection model to rapidly draw the calcified region from coronary OCT images using a bounding box. We measure the uncertainty of predictions based on the expected calibration errors, thus assessing the certainty level of detection results. To calibrate confidence scores of predictions, we implement dependent logistic calibration using each detection result's confidence and center coordinates. We implemented an object detection module to draw the boundary of the calcified region at a rate of 140 frames per second. With the calibrated confidence score of each prediction, we lower the uncertainty of predictions in calcification detection and eliminate the estimation bias from various object detection methods. The calibrated confidence of prediction results in a confidence error of , suggesting that the confidence calibration on calcification detection could provide a more trustworthy result. Given the rapid detection and effective calibration of the proposed work, we expect that it can assist in clinical evaluation of treating the CAD during the imaging-guided procedure.

Interventional Pain Procedures: A Narrative Review Focusing On Safety and Complications. PART 2 Interventional Procedures For Back Pain.

In patients where conservative approaches have failed to relieve from chronic pain, interventional procedures may be an option in well selected patients. In recent years there has been an increase in the use and development of invasive procedures. Concomitantly, there has also been an increase in the complications associated with these procedures. Taken this into consideration, it is important for healthcare providers to take a cautious and vigilant approach, with a focus on patient safety, in order to minimize the risk of adverse events and ensure the best possible outcome for the patient. This may include careful selection of patients for procedures, use of proper techniques and equipment, and close monitoring and follow-up after the procedure. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopy or ultrasound-guided) interventional procedures and provide strategies to reduce the risk of these complications. We conclude that although complications from interventional pain procedures can be mitigated to a certain degree, they cannot be eliminated altogether. In order to avoid adverse events, patient safety should be given considerable attention and physicians should be constantly aware of the possibility of developing complications.

Contrast-enhanced ultrasound for abdominal image-guided procedures.

Since FDA approval for contrast-enhanced ultrasound (CEUS), clinical applications have increased to include diagnostic imaging of hepatic, renal, and other abdominal lesions. The modality has also demonstrated utility in certain image-guided procedures. Intravascular ultrasound contrast agents use microbubbles to improve visibility of solid tumors. Lesions not well seen on grayscale or Doppler ultrasound may become amenable to CEUS-guided biopsy or ablation. This pictorial essay provides eleven examples to illustrate the current use of CEUS in a variety of abdominal image-guided procedures.Hepatic, renal, peritoneal, and soft tissue cases are presented. CEUS can improve visualization and targeting in abdominal image-guided procedures, without nephrotoxicity or radiation exposure.

Image-Guided Ablation of Recurrent or Unresectable Intrahepatic Cholangiocarcinoma

PurposeTo assess the safety and effectiveness of image-guided ablation of recurrent or unresectable intrahepatic cholangiocarcinoma (ICC). Materials and MethodsIn this retrospective study, 25 patients (14 women; age, 36–84 years) underwent 37 image-guided liver tumor ablation procedures to treat 47 ICCs (May 2004 to January 2022). At initial diagnosis, 20 patients had Stage 1 or 2 disease and 5 had Stage 3 or 4 disease. Before ablation, 19 (76.0%) of the 25 patients had progressed through prior treatments, including resection (n = 11), chemotherapy (n = 11), transarterial embolization (n = 3), or radiotherapy (n = 1); 6 (24.0%) of the 25 patients were treatment naïve. Ablation modality selection was based on patient and tumor characteristics and operator preference. Primary outcomes included local progression–free survival (LPFS) and overall survival (OS) after ablation. Statistical analysis included Kaplan-Meier (KM) survival analyses and Cox proportional hazards models. ResultsThe mean ablated tumor size was 2.0 cm ± 1.2 (range, 0.5–5.0 cm). The 1-, 2-, and 5-year LPFS rates were 84.0% (95% CI, 72.9–96.8), 73.0% (95% CI, 59.0–90.4), and 59.5% (95% CI, 41.6–85.1), respectively. The 1-, 2-, and 5-year secondary LPFS rates were 89.5% (95% CI, 80.2–99.9), 81.9% (95% CI, 69.4–96.6), and 75.6% (95% CI, 60.2–94.9). The 1-, 2-, and 5-year LPFS rates for tumors ≤2 cm in size were all 95.8% (95% CI, 88.2–100.0). The 1-, 2-, and 5-year OS rates were 78.5% (95% CI, 63.5–97.2), 68.4% (95% CI, 51.3–91.1), and 43.5% (95% CI, 23.5–80.5). Larger tumor size was associated with decreased time to local progression (hazard ratio, 1.93; P = .012). ConclusionsPercutaneous ablation provided favorable intermediate to long-term disease control for patients with recurrent or inoperable cholangiocarcinoma.

Introduction to interventional oncology: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

Interventional radiology (IR) is a valuable resource when caring for pediatric solid tumor patients. As minimally invasive, image-guided procedures become more relied upon to answer challenging diagnostic questions and provide alternative therapeutic options, IR is poised to become a contributing member of the multidisciplinary oncology team. Improved imaging techniques allow for better visualization during biopsy procedures, transarterial locoregional treatments have the potential to deliver targeted cytotoxic therapy while limiting systemic side effects, and percutaneous thermal ablation can be used to treat chemo-resistant tumors of various solid organs. Additionally, interventional radiologists are able to perform routine, supportive procedures for oncology patients that include central venous access placement, lumbar punctures, and enteric feeding tube placements with high levels of technical success and excellent safety profiles.

Augmenting Image-Guided Procedures through In Situ Visualization of 3D Ultrasound via a Head-Mounted Display.

Medical ultrasound (US) is a commonly used modality for image-guided procedures. Recent research systems providing an in situ visualization of 2D US images via an augmented reality (AR) head-mounted display (HMD) were shown to be advantageous over conventional imaging through reduced task completion times and improved accuracy. In this work, we continue in the direction of recent developments by describing the first AR HMD application visualizing real-time volumetric (3D) US in situ for guiding vascular punctures. We evaluated the application on a technical level as well as in a mixed-methods user study with a qualitative prestudy and a quantitative main study, simulating a vascular puncture. Participants completed the puncture task significantly faster when using 3D US AR mode compared to 2D US AR, with a decrease of 28.4% in time. However, no significant differences were observed regarding the success rate of vascular puncture (2D US AR-50% vs. 3D US AR-72%). On the technical side, the system offers a low latency of 49.90 ± 12.92 ms and a satisfactory frame rate of 60 Hz. Our work shows the feasibility of a system that visualizes real-time 3D US data via an AR HMD, and our experiments show, furthermore, that this may offer additional benefits in US-guided tasks (i.e., reduced task completion time) over 2D US images viewed in AR by offering a vividly volumetric visualization.

Introduction to interventional radiology's role in palliative care for children with cancer: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper.

As palliative care continues to be an area of increasing emphasis in pediatric oncology programs, it is important to raise awareness about minimally invasive, image-guided procedures that can supplement more conventional palliative interventions, such as systemic analgesics, external beam radiation, and locoregional anesthesia. These procedures, when performed for appropriately selected patients, can often facilitate discharge from an inpatient facility, and help patients meet their end-of-life goals. This article specifically discusses three palliative procedures performed by interventional radiologists that can assist pediatric palliative care teams in: (a) percutaneous thermal ablation of painful bone metastases, (b) cryoneurolysis, and (c) tunneled drainage catheter placement for malignant pleural effusions and ascites.

Safety of High-Frequency Jet Ventilation During Image-Guided Thermal Ablation Procedures.

Percutaneous thermal ablative technique is a common radiological procedure for malignant lesions treatment. Controlled assisted ventilation during general anesthesia is the usual mode of ventilation, but high-frequency jet ventilation (HFJV) can be a helpful alternative for the operator. The objective was to evaluate the safety of HFJV during thermal ablation procedures. This monocentric prospective analysis included adult patients undergoing percutaneous thermal ablation procedures for abdominal tumor performed under HFJV. Procedures with a transpulmonary path were excluded. The primary outcome was the incidence of respiratory complications. Secondary outcomes included gas exchange modifications (hypercapnia, hypoxemia, pulmonary atelectasis) and the incidence of barotrauma. Sixty patients were included during the study period. The mean duration time was 88min. All procedures went according to the protocol and there was no respiratory complication. There was no barotrauma event. Three patients had an exhaled capnia above 45mmHg at the end of the procedure which normalized within 10min of conventional ventilation. HFJV during thermal ablation procedures is safe regarding gas exchange and barotrauma. This technique could be an interesting alternative to conventional ventilation during image-guided thermal ablation procedures. Clinical Trials database This study was registered in Clinical Trials database (NCT04209608).

Establishment of an interdisciplinary vascular anomalies program in Tanzania, East Africa.

The aim of this project is the sustainable implementation of a vascular anomalies (VA) program in Tanzania. In 2021 the first interdisciplinary VA program was initiated at Muhimbili National Hospital (MNH), Dar Es Salaam, Tanzania in a stepwise approach. During the planning phase the clinical need for minimally-invasive therapies of VAs and the preexisting structures were assessed by the local Interventional Radiology (IR) team at MNH. During the initiation phase, an IR team from two German VA centers joined the interdisciplinary team at MNH for clinical workup, image-guided procedures and follow-up. VA patients were recruited from existing patient records or seen at clinics as de novo presentations following nationwide advertisement. In the post-processing phase joined online conferences for follow-up and support in management of new patients were established. Further follow-up was supported by attending providers from other established VA centers, traveling to bolster the primary operators of MNH. The first interdisciplinary VA program was successfully launched in Tanzania. Minimally-invasive treatments were successfully trained, by performing ultrasound-guided sclerotherapy with polidocanol and bleomycin in twelve patients with slow-flow malformations, one endovascular embolization of a high-flow malformation, and medical treatment of an aggressive infantile hemangioma. Regular online follow-up presentations have been initiated. Follow-up evaluation and required treatment was sustained when appropriate. The presented "hands-on" training set the ground for the first interdisciplinary VA program in Tanzania. This framework is expected to establish comprehensive and sustainable care of patients with VAs in East Africa and can serve as a blueprint for other sites.

Imaging incidence and type in primary care patients with low back pain: a cross-sectional study on new referrals to an Australian specialist spinal surgical centre.

Introduction Low back pain (LBP) is common and a significant cause of morbidity. Many patients receive inappropriate imaging for LBP in primary care. Aim To explore the incidence and type of spinal imaging conducted for LBP patients referred from general practice for specialist surgical opinion, and evaluate whether imaging conformed to clinical guidelines. Methods Audit of a sequential cohort (n = 100) of new LBP patients referred from primary care for specialist opinion at a suburban Australian capital city independent Spinal Centre. Results In the 6 months before referral, 90% (95% CI 83-95%) of patients underwent spinal imaging. Imaging was performed in 95% of those who did and 79% of those who did not meet guidelines for radiological investigation. 35% of patients were inappropriately imaged and 3% inappropriately not imaged. Spinal computed tomography (CT) imaging was used in 52% of patients, magnetic resonance imaging (MRI) in 42% and image-guided lumbar spinal interventional procedures in 28%. Discussion Most patients with LBP referred for surgical opinion have diagnostic radiological investigations whether or not it is indicated by clinical guidelines. The more frequent use of spinal CT compared to MRI may be due to idiosyncrasies of the Australian Medicare Benefits Schedule (MBS) rebate system. The findings of this pilot study provide support for the changes recommended by the 2016 MBS Review Taskforce on LBP that permit GP access to subsidised lumbar MRI, while constraining access to lumbar CT, and provide novel data about spinal imaging and practice in this cohort of patients.

Assessment of occupational eye lens exposure during image-guided orthopedic procedures

This study aimed to investigate the level of exposure of eye lenses in orthopedic surgeons performing routine clinical work and to determine future monitoring practice, as Serbian radiation protection law still employs higher limits. The dose was measured monthly in terms of H (0.03) with three different dosimeters placed on a 3-D-printed headband, worn on a forehead by three orthopedic surgeons, during all procedures involving fluoroscopy. The mean dose for the left and right eye was 271 ? 109 ?Sv and 269 ? 101 ?Sv, respectively, with no significant difference (p-value 0.977) between the left and right eye observed. Considering the highest recorded monthly value, the annual dose is expected to be 4.85 mSv without protective items, well below the new ICRP limit of 20 mSv. There was no observed correlation between eye lens dose and both fluoroscopy time and exposure parameters. Considering the cumulative impact of dose and the evidence pointing to an elevated incidence of lenticular opacities for cumulative doses exceeding 10 mSv, it is advisable to institute ongoing monitoring, especially when new surgeons incorporate image-guided procedures or when novel techniques are introduced into surgical practice.

Enhancing mummy ‘palaeobiographies’ through the use of multidisciplinary techniques and approaches

Scientific examination of mummies has provided a better understanding of the ancestry, diet, disease, medical practices, mummification processes, culture and society of human populations worldwide and from different epochs. However, many examinations have been invasive and/or destructive, leading to current-day concerns among archaeologists and mummy custodians about this methodology. Multidisciplinary approaches, notably minimally invasive biopsy, endeavour to maximise the amount of data obtained from a sample whilst minimising its size and the effects on the mummy. As an illustration of the wealth of data that can be obtained from non- and minimally invasive image-guided procedures on wrapped mummified bodies, we report here on such a study of Takabuti, an Egyptian woman who lived in Thebes during the first millennium BCE.Multiplanar and 3D reconstructive computerised whole-body tomographic imaging (CT) revealed age at death and confirmed the inscriptional evidence from the coffin regarding sex. A notable finding was ante-mortem damage to the ribs indicative of a blow by a sharp, possibly curved, object from behind, suggesting that Takabuti was murdered. Fifty milligrams of bone and thigh muscle were taken for respectively genomic and proteomic analysis. mtDNA revealed the rare Eurasian H4a1 haplogroup suggestive of the introduction of new gene pools during the Late Period. Identification and quantification of the structural and functional proteins and metabolically important enzymes indicate protracted leg muscle activity in the hours before death. Chemical analysis, microscopy and radiocarbon dating of 20–30 mg needle biopsy samples of the packing material inserted during mummification discovered wood shavings, including imported cedar, and congealed resin. Organic analyses revealed the resin to be largely vegetal in origin including wood and aromatic/preservative oils derived from Pinaceae species, identical to the mummification balm removed from the original bandages. Once the age of the trees from which the sawdust was derived has been taken into account, the packing material’s radiocarbon date indicated mummification in the Third Intermediate Period and in keeping with the previously dated hair and the stylistic dating of the coffin that placed it in the 25th Dynasty.We have shown that CT scanning combined with targeted invasive biopsy needle sampling provides a wealth of scientific information with minimal disturbance to the mummy. Molecular, biochemical and geochemical analytical techniques allow statistically robust replicate sampling but require the removal of only milligram quantities. This approach forms the basis of a generic ‘palaeobiographical’ approach to the examination of naturally and artificially preserved bodies in which both soft tissues and bone are present.

Ultrasound-guided retrograde tibial access through chronically occluded tibial arteries: a last resort recanalization technique.

PURPOSE We aimed to demonstrate the feasibility of ultrasound (US)-guided retrograde tibial access through chronically occluded tibial arteries as a bailout endovascular recanalization procedure in patients with critical limb ischemia (CLI). METHODS Fifty-one CLI patients with failed conventional antegrade tibiopedal recanalization required retrograde tibiopedal access in the same session. In all of these patients, the target tibial artery was chronically occluded in at least the distal half of the cruris. Access attempts were made under real-time US by a single operator experienced in image-guided vascular access procedures. Fluoroscopy was used only as an adjunct during advancement of a 0.018 inch guidewire. If access to the artery was successful by the retrograde route, the occluded artery was usually predilated with a 2 mm balloon, and the standard endovascular treatment was mostly performed through the antegrade route. RESULTS Patients had athereosclerosis (n=35) or Buerger's disease (n=32) and presented with Rutherford category IV and category V. Successful placement of a guidewire in the occluded artery lumen was achieved in 81% of all patients, whereas, treatment success, i.e. angiographic demonstration of in-line flow at the end of procedure, was achieved in 49%. No significant procedure-related complications were observed. Of 33 limbs with initially successful endovascular treatment, 6 required minor and 1 required major amputation during follow-up. CONCLUSION US-guided retrograde access through completely occluded tibial arteries is difficult but feasible. Half of the tibial arteries that could not be recanalized otherwise were converted to successful recanalization by this method.

Multi-objective optimization for X-ray exposure reduction during image-guided needle-based procedure

ABSTRACT Nowadays, an increasing number of surgical operations are guided by intra-operative imaging, especially Cone Beam Computed Tomography (CBCT) systems using X-rays. We deal with the problem of reducing the X-ray dose received by the patient and the staff while ensuring reasonable visibility of the region of interest during needle-based ablation procedures. We achieved this by implementing a numerical multi-optimisation algorithm using as input numerical X-ray simulation providing both medical staff and patient exposure, as well as an estimation of the fluorescence-based ablation needle visibility. Our algorithm can find the Pareto front in this multi-objective function problem. The Pareto front is suggested to the operator who can then select the best configuration according to the defined priority level regarding each exposure and visibility. We have been able to reduce in simulations the clinician’s dose by 61.8%, the patient’s dose by 45.1% and increase the region of interest visibility by 28.6% in-plane axis view and, respectively, by 41.5%, 60.4% and 41.0% in progression view.

Management of doses from medical exposures in interventional radiology: an integrative review

Interventional radiology (IR) uses minimally invasive image-guided procedures that may require a long duration and deliver high radiation doses to the patient. The most current studies on management and dose reduction in IR have shown to be of fundamental importance in radiation protection practices. The objective of this study was to survey what has been published in the national and international literature on the doses received by patients undergoing IR procedures. It consisted of an integrative review study carried out in Scielo, Pubmed, and INIS databases in the time frame of 2016-2021, using as descriptors: interventional radiology, radiation injuries, radiological protection, dosimetry; and their equivalents in English: interventional radiology, radiation injuries, radiological protection, and dosimetry. The initial sample consisted of 68 full articles related to the theme, published during the study period. Of these, 11 articles were selected and made up the final sample. The results indicate that the use of software in dose management and monitoring has proven to be an important tool in radiological protection. The implementation of dose reduction strategies and increased awareness about the use and effects of radiation result in significantly lower doses to both professionals and patients. No national study on dose management has been identified, highlighting the need to promote the subject in the country. The main recommendations identified were the introduction of technologies and the training of the workers involved.

PP109 Efficacy And Safety Of High-Intensity Focused Ultrasound In Parkinson’s Disease

IntroductionParkinson’s disease (PD) is the second most common neurodegenerative disease in the world. High-intensity focused ultrasound (HIFU) is a new non-invasive therapeutic option for treating the motor symptoms of PD. HIFU is an imaging-guided procedure for therapeutic brain ablation that has been used for patients with essential tremor and neuropathic pain. It is indicated for patients older than 22 years of age who have PD that is refractory to drug treatment and are ineligible for surgery. The objective of this study was to conduct an early assessment of HIFU subthalamotomy for the treatment of motor symptoms in patients with PD.MethodsHIFU was identified by the early awareness and alert system, SINTESIS- nuevas tecnologías, of the Agencia de Evaluación de Tecnologías Sanitarias at the Instituto de Salud Carlos III. Relevant literature published to October 2021 was identified by searching PubMed, EMBASE, ClinicalTrials.gov, and the Cochrane Library.ResultsOne prospective study and one randomized controlled trial (RCT) were found that assessed the efficacy and safety of HIFU subthalamotomy for treating the motor symptoms of PD. The Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale Part III (MDS-UPDRS III) was used to measure changes in symptoms (>30% change from baseline was considered clinically relevant). Both studies reported a reduction of symptoms in the intervention group. The MDS-UPDRS III score changed from 16.6 to 7.5 six months after treatment in the prospective study and from 19.9 to 9.9 four months after treatment in the RCT (a decrease of 11.6 points was observed after 12 months). The main adverse events reported were dyskinesia, speech and gait disturbances, and weakness, all of which resolved without treatment.ConclusionsThe results regarding the efficacy and safety of HIFU for treating the motor symptoms of PD are promising. HIFU is a non-invasive procedure that eliminates the risks associated with surgery. Although rapid diffusion of this technology is expected, further studies and economic evaluation are needed.

Safety and technical success of diphenhydramine as an alternative local anaesthetic agent for radiology procedures

To evaluate retrospectively the safety and technical success of subcutaneous diphenhydramine as an alternative local anaesthetic for radiology procedures. Between January 2000 and April 2021, 84 image-guided procedures were performed in 81 adult patients (mean age 61 years, 86% female) using 1% injectable diphenhydramine as a local anaesthetic. Indications were history of severe allergy to "-caine" local anaesthetics in 76 (90%) patients and recent administration of bupivacaine liposomal injectable suspension in eight (10%) patients. Twelve of the 84 (14%) procedures were performed with concomitant moderate sedation. Patient characteristics, procedural techniques, and clinical outcomes were reviewed. Early and delayed (30-day) complications were classified as either related to local diphenhydramine injection or to the procedure itself. Procedure-related complications were gradated using the Clavien-Dindo system. Percutaneous biopsy was the most frequently performed procedure (57/84, 67%). Fifty-nine (70%) of the 84 procedures were ultrasound guided. The most common procedural site was the breast (34/84, 40%). All procedures were technically successful. There were two minor injection-related complications related to post-procedural pain. A single minor procedure-related complication involved a patient requiring hospital admission for post-renal biopsy related haematuria. Injectable diphenhydramine appears to be a safe and effective local anaesthetic alternative in patients with "-caine" class contraindications undergoing radiology procedures. A future prospective trial would be useful to assess the safety profile in an large cohort of patients.