Cone-beam computed tomography fusion and navigation for real-time positron emission tomography-guided biopsies and ablations: a feasibility study

Could Maximum SUV be Used as Imaging Guidance in Large Lung Lesions Biopsies? Double Sampling Under PET-CT/XperGuide Fusion Imaging in Inhomogeneous Lung Uptaking Lesions to Show That it can Make a Difference

Introduction: The purpose of this study is to evaluate the diagnostic value of positron emission computed tomography-cone beam computed tomography (PET/CT-CBCT) fusion guided percutaneous biopsy, targeted to the maximum standardized uptake value (SUVmax) and minimum standardized uptake value (SUVmin) of large lung lesions. Materials and Methods: Inside a larger cohort of PET/CT-CBCT guided percutaneous lung biopsies, 10 patients with large pulmonary lesions (diameter > 30 mm) were selected retrospectively. These patients have been subjected to double biopsy sampling respectively in the SUVmax area and in the SUVmin area of the lesion. Technical success has been calculated. For each sample, the percentage of neoplastic, inflammatory, and fibrotic cells was reported. Furthermore, the possibility of performing immunohistochemical or molecular biology investigations to specifically define the biomolecular tumor profile was analyzed. Results: Nine lesions were found to be malignant, one benign (inflammation). Technical success was 100% (10/10) in the SUVmax samples and 70% (7/10) in the SUVmin samples (P-value: .21). In the first group, higher percentages of neoplastic cells were found at pathologic evaluation, while in the second group areas of inflammation and fibrosis were more represented. The biomolecular profile was obtained in 100% of cases (9/9) of the first group, while in the second group only in 33.3% of cases (2/6), with a statistically significant difference between the 2 groups (P-value: .011). Conclusion: A correlation between the standardized uptake value value and the technical success of the biopsy sample has been identified. PET/CT-CBCT guidance allows to target the biopsy in the areas of the tumor which are richer in neoplastic cells, thus obtaining more useful information for the planning of patient-tailored cancer treatments.

Irreversible electroporation for pancreatic cancer using intraprocedural cone-beam computed tomography fusion navigation: a case report

Background

Patients diagnosed with locally advanced pancreatic cancer are usually not eligible for surgical resection because of significant vascular involvement. Stereotactic body radiation therapy and chemotherapy are the treatments recommended by the National Comprehensive Cancer Network criteria. For patients who do not respond to or tolerate stereotactic body radiation therapy and/or chemotherapy, a new option is irreversible electroporation. Irreversible electroporation is a nonthermal minimally invasive ablation technique that uses electrical pulses to induce apoptosis of tumor cells without damage to the extracellular matrix, thus preserving ducts and vessels. Irreversible electroporation requires very precise needle placement, which has limited its ubiquitous use. Intraprocedural cone-beam computed tomography with navigation can be fused with previous imaging to provide real-time tumor navigation capabilities during the procedure to allow for more accurate needle placement and treatment. Here, we present a patient who underwent percutaneous irreversible electroporation with intraprocedural cone-beam computed tomography fusion guidance to treat his pancreatic cancer.

Case presentation

The patient, an 88-year-old White male, initially presented with abdominal pain, and was ultimately diagnosed with locally advanced pancreatic cancer. He has an excellent performance status and no other comorbidities. He was started on chemotherapy and radiation therapy, with good response. However, continued vascular involvement of the tumors precluded him from safe surgical resection. The patient underwent irreversible electroporation with intraprocedural cone-beam computed tomography fusion navigation. The primary lesion demonstrates no residual tumor, and the soft tissue involvement of the adjacent vasculature has stabilized.

Conclusions

Although not curative on its own, irreversible electroporation holds promise as a treatment option for patients with locally advanced pancreatic cancer to increase downsizing to curative surgery or increase quality of life. Cone-beam computed tomography navigation can improve irreversible electroporation by providing guidance during needle guidance. Image fusion with previous advanced imaging can improve lesion visualization and targeting, thereby improving the effectiveness of irreversible electroporation.

Alternative methods for local ablation-interventional pulmonology: a narrative review

OBJECTIVE

To discuss and summarise the background and recent advances in the approach to bronchoscopic ablative therapies for lung cancer, focusing on focal parenchymal lesions.

BACKGROUND

This series focusses on the challenges highlighted by increasing recognition of the prognostically more favourable oligometastatic disease rather than the more frequent, but prognostically poor, high tumour burden metastatic disease. While surgery, stereotactic body radiation therapy (SBRT), and trans-thoracic percutaneous ablative techniques such as microwave (MWA) and radiofrequency ablation (RFA) are well recognised options for selected cases of pulmonary oligometastasis, bronchoscopic approaches to pulmonary tumour ablation are becoming realistic alternatives. An underlying tenet driving research and implementation in this domain is that percutaneous ablative techniques are obliged to traverse the pleura leading to a high rate of pneumothorax, and risks also goes up for peri-vascular lesions. Historically low yield bronchoscopic targeting of isolated peripheral tumors have significantly improved by incorporating multi-modality high resolution imaging and processing, including navigation planning and real-time image guidances (ultrasound, electromagnetic navigation, cone-beam CT). Combining advanced image guidance with ablative technology adaptations for bronchoscopic delivery opens up the options for high dose local ablative therapies that may reduce transthoracic complications and provide palliative to curative options for limited stage primary and oligometastatic diseases.

METHODS

We conduct a narrative review of the literature summarizing the history of bronchoscopic tumor ablation approaches, technical details including biologic rational for their uses, and current evidence for each modality, as well as investigations into future applications. Because of the relative paucity of prospective studies, we have been very inclusive in our inclusion of experiences from the published clinical databases.

CONCLUSIONS

Whilst surgical resection and SBRT remain the current mainstay of curative therapies for peripheral cancers, in the foreseeable future, developments and further research will see bronchoscopic ablative therapies become viable lung sparing alternatives in those deemed suitable. The future is bright.

PET- and SPECT-based navigation strategies to advance procedural accuracy in interventional radiology and image-guided surgery

INTRODUCTION

Nuclear medicine has a crucial role in interventional strategies where a combination between the increasing use of targeted radiotracers and intraprocedural detection modalities enable novel, but often complex, targeted procedures in both the fields of interventional radiology and surgery. 3D navigation approaches could assist the interventional radiologist or surgeon in such complex procedures.

EVIDENCE ACQUISITION

This review aimed to provide a comprehensive overview of the current application of computer-assisted navigation strategies based on nuclear imaging to assist in interventional radiology and image-guided surgery. This work starts with a brief overview of the typical navigation workflow from a technical perspective, which is followed by the different clinical applications organized based on their anatomical organ of interest.

EVIDENCE SYNTHESIS

Although many studies have proven the feasibility of PET- and SPECT-based navigation strategies for various clinical applications in both interventional radiology and surgery, the strategies are spread widely in both navigation workflows and clinical indications, evaluated in small patient groups. Hence, no golden standard has yet been established.

CONCLUSIONS

Despite that the clinical outcome is yet to be determined in large patient cohorts, navigation seems to be a promising technology to translate nuclear medicine findings, provided by PET- and SPECT-based molecular imaging, to the intervention and operating room. Interventional Nuclear Medicine (iNM) has an exciting future to come using both PET- and SPECT-based navigation.

Role of Fusion Imaging in Image-Guided Thermal Ablations

Thermal ablation (TA) procedures are effective treatments for several kinds of cancers. In the recent years, several medical imaging advancements have improved the use of image-guided TA. Imaging technique plays a pivotal role in improving the ablation success, maximizing pre-procedure planning efficacy, intraprocedural targeting, post-procedure monitoring and assessing the achieved result. Fusion imaging (FI) techniques allow for information integration of different imaging modalities, improving all the ablation procedure steps. FI concedes exploitation of all imaging modalities’ strengths concurrently, eliminating or minimizing every single modality’s weaknesses. Our work aims to give an overview of FI, explain and analyze FI technical aspects and its clinical applications in ablation therapy and interventional oncology.

Comparison Between CBCT and Fusion PET/CT-CBCT Guidance for Lung Biopsies

PURPOSE

To establish the feasibility of performing percutaneous biopsy of lung lesions guided by fusion PET/CT-CBCT and to evaluate whether the metabolic information provided by a prior PET/CT scan add incremental benefits for diagnosis.

METHODS

We retrospectively reviewed data from 180 patients who underwent CBCT-guided lung biopsy (group 1-90 cases) or PET/CT-CBCT fusion-guided lung biopsy (group 2-90 cases). Technical and clinical success was calculated. We also evaluated the agreement between biopsy and definitive histology and the possibility to carrying out immunehistochemical and molecular biology analyses.

RESULTS

Technical success was achieved in 84/90 (93.3%) cases for group 1 and 89/90 (98.9%) for group 2 cases (p 0.054). Clinical success was achieved in 80/94 (95.2%) cases for group 1 and 88/89 (98.9%) cases for group 2. Sensitivity, specificity, positive and negative predictive values and accuracy rate were, respectively, 94.5%, 100.0%, 100.0%, 73.3% and 95.2% for group 1 and 98.6%, 100.0%, 100.0%, 94.4% and 98.9% for group 2 (p 0.167). Agreement between biopsy and definitive histology was reached in 85.7% for group 1 and in 96.2% for group 2 (p 0.211). Immunohistochemical and molecular biology investigations were possible in 66.7% for group 1 and in 77.0% for group 2 (p 0.297). No major complication occurred.

CONCLUSIONS

PET/CT-CBCT-guided lung biopsy is a feasible technique. In our retrospective case series, we found a higher clinical success rate, but no statistical difference was found.

State of the Art: Toward Improving Outcomes of Lung and Liver Tumor Biopsies in Clinical Trials-A Multidisciplinary Approach

PURPOSE

National Cancer Institute (NCI)-sponsored clinical trial network studies frequently require biopsy specimens for pharmacodynamic and molecular biomarker analyses, including paired pre- and post-treatment samples. The purpose of this meeting of NCI-sponsored investigators was to identify local institutional standard procedures found to ensure quantitative and qualitative specimen adequacy.

METHODS

NCI convened a conference on best biopsy practices, focusing on the clinical research community. Topics discussed were (1) criteria for specimen adequacy in the personalized medicine era, (2) team-based approaches to ensure specimen adequacy and quality control, and (3) risk considerations relevant to academic and community practitioners and their patients.

RESULTS AND RECOMMENDATIONS

Key recommendations from the convened consensus panel included (1) establishment of infrastructure for multidisciplinary biopsy teams with a formalized information capture process, (2) maintenance of standard operating procedures with regular team review, (3) optimization of tissue collection and yield methodology, (4) incorporation of needle aspiration and other newer techniques, and (5) commitment of stakeholders to use of guideline documents to increase awareness of best biopsy practices, with the goal of universally improving tumor biopsy practices.

Diagnostic value of navigation-guided core needle biopsy in deep regions of the head and neck with focal FDG uptake on 18F-FDG PET/CT

PURPOSE

The aim of this study was to evaluate the feasibility and diagnostic accuracy of core needle biopsy (CNB) in patients with focal fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) in deep regions of the head and neck, with the guidance of infrared navigation integrated with PET.

MATERIALS AND METHODS

Patients with suspected primary or recurrent malignancies of the head and neck on PET/CT, from June 2016 to December 2018, were included. Before CNB, the region of interest was delineated and the ideal needle entry points, target sites, and a number of trajectories were designed on iPlan CMF 3.0. CNB was performed with the guidance of infrared navigation integrated with PET, according to the pre-plan. Sensitivity and diagnostic accuracy were analyzed by comparing the biopsy results with the final diagnosis.

RESULTS

Thirty-one consecutive patients were included. Among the 31 lesions, 18 were skull base, six were infratemporal fossa, and seven were maxillary region. The median values for SUVmax, SUVmean, and MTV were 6.09 (range: 1.43-24.67), 3.41 (range: 0.38-20.96), and 25.83 (range: 3.54-361.94) for the 31 lesions, respectively. Combined needle approaches were employed, including temporal (nine), subzygomatic (19), paramaxillary (11), and retromandibular (16) approaches. The depths of the 31 deep-region lesions, measured from the needle entry site on the skin to the target point, ranged from 1.33 cm to 7.82 cm (median 4.25 cm). There were three non-diagnostic lesions resulting from CNB, and these were all skull base. The diagnostic accuracy was 90.3%, while the sensitivity was 88%. According to the binary logistic regression for the final diagnosis, the only significant parameter was SUVmax.

CONCLUSION

With the guidance of navigation integrated with PET, CNB is a feasible and accurate diagnostic modality, which is also an alternative to open biopsy in patients with suspected primary or recurrent malignancies in deep regions of the head and neck on PET/CT.

Using the Hybrid Operating Room in Thoracic Surgery: A Paradigm Shift

We describe the integration of the hybrid operation room cone-beam computed tomography (CT) scan technology into the practice of general thoracic surgery. The combination of the following three techniques: (1) cone-beam CT scan augmented navigational bronchoscopy, (2) cone-beam CT-guided percutaneous biopsy and/or fiducial placement, and (3) fiducial or image-guided video-assisted thoracic surgery resection, into a single-stage, single-provider procedure allows for diagnosis and treatment in one setting. Rapid on-site evaluation of cytological or pathology specimens is key to this "all-in-one" approach. The time from diagnosis to curative treatment can significantly be reduced using the hybrid operation room technology, leading to decreased upstaging, increased survival and facilitating the otherwise difficult intraoperative detection and resection of small and deeper lesions. Not only does this benefit the overall thoracic healthcare of the community but also provides a cost-effective paradigm for the institution.

Evaluation of the tumor registration error in biopsy procedures performed under real-time PET/CT guidance

PURPOSE

The purpose of this study is to quantify tumor displacement during real-time PET/CT guided biopsy and to investigate correlations between tumor displacement and false-negative results.

METHODS

19 patients who underwent real-time ¹⁸ F-FDG PET-guided biopsy and were found positive for malignancy were included in this study under IRB approval. PET/CT images were acquired for all patients within minutes prior to biopsy to visualize the FDG-avid region and plan the needle insertion. The biopsy needle was inserted and a post-insertion CT scan was acquired. The two CT scans acquired before and after needle insertion were registered using a deformable image registration (DIR) algorithm. The DIR deformation vector field (DVF) was used to calculate the mean displacement between the pre-insertion and post-insertion CT scans for a region around the tip of the biopsy needle. For 12 patients one biopsy core from each was tracked during histopathological testing to investigate correlations of the mean displacement between the two CT scans and false-negative or true-positive biopsy results. For 11 patients, two PET scans were acquired; one at the beginning of the procedure, pre-needle insertion, and an additional one with the needle in place. The pre-insertion PET scan was corrected for intraprocedural motion by applying the DVF. The corrected PET was compared with the post-needle insertion PET to validate the correction method.

RESULTS

The mean displacement of tissue around the needle between the pre-biopsy CT and the postneedle insertion CT was 5.1 mm (min = 1.1 mm, max = 10.9 mm and SD = 3.0 mm). For mean displacements larger than 7.2 mm, the biopsy cores gave false-negative results. Correcting pre-biopsy PET using the DVF improved the PET/CT registration in 8 of 11 cases.

CONCLUSIONS

The DVF obtained from DIR of the CT scans can be used for evaluation and correction of the error in needle placement with respect to the FDG-avid area. Misregistration between the pre-biopsy PET and the CT acquired with the needle in place was shown to correlate with false negative biopsy results.

Prospective Randomized Trial for Image-Guided Biopsy Using Cone-Beam CT Navigation Compared with Conventional CT

PURPOSE

To compare cone-beam computed tomography (CT) navigation vs conventional CT image guidance during biopsies.

MATERIALS AND METHODS

Patients scheduled for image-guided biopsies were prospectively and randomly assigned to conventional CT guidance vs cone-beam CT navigation. Radiation dose, accuracy of final needle position, rate of histopathologic diagnosis, and number of needle repositions to reach the target (defined as pullback to adjust position) were compared.

RESULTS

A total of 58 patients (mean age, 57 y; 62.1% men) were randomized: 29 patients underwent 33 biopsies with CT guidance and 29 patients with 33 lesions underwent biopsy with cone-beam CT navigation. The average body mass index (BMI) was similar between groups, at 28.8 kg/m(2) ± 6.55 (P = .18). There was no difference between groups in terms of patient and lesion characteristics (eg, size, depth). The average lesion size was 29.1 ± 12.7mm for CT group vs 32.1mm ±16.8mm for cone-beam CT group (P < 0.59). Location of lesions was equally divided between the 2 groups, 20 lung lesions, 18 renal lesions and 20 other abdominal lesions. Mean number of needle repositions in the cone-beam CT group was 0.3 ± 0.5, compared with 1.9 ± 2.3 with conventional CT (P < .001). The average skin entry dose was 29% lower with cone-beam CT than with conventional CT (P < .04 accounting for BMI). The average estimated effective dose for the planning scan from phantom data was 49% lower with cone-beam CT vs conventional CT (P = .018). Accuracy, defined as the difference between planned and final needle positions, was 4.9 mm ± 4.1 for the cone-beam CT group, compared with 12.2 mm ± 8.1 for conventional CT (P < .001). Histopathologic diagnosis rates were similar between groups, at 90.9% for conventional CT and 93.9% for cone-beam CT (P = .67).

CONCLUSIONS

Cone-beam CT navigation for biopsies improved targeting accuracy with fewer needle repositions, lower skin entry dose, and lower effective dose for planning scan, and a comparable histopathologic diagnosis rate.

PET-Based Percutaneous Needle Biopsy

PET can be used to guide percutaneous needle biopsy to the most metabolic lesion, improving diagnostic yield. PET biopsy guidance can be performed using visual or software coregistration, electromagnetic needle tracking, cone-beam computed tomography (CT), and intraprocedural PET/CT guidance. PET/CT-guided biopsies allow the sampling of lesions that may not be clearly visible on anatomic imaging, or of lesions that are morphologically normal. PET can identify suspicious locations within complex tumors that are most likely to contain important diagnostic and prognostic information.

18F-FDOPA PET/CT-Guided Radiofrequency Ablation of Liver Metastases from Neuroendocrine Tumours: Technical Note on a Preliminary Experience

AIM

To review our preliminary experience with 6-L-18F-fluorodihydroxyphenylalanine (18F-FDOPA) PET/CT-guided radiofrequency ablation (RFA) of liver metastases from neuroendocrine tumours (NETs).

MATERIALS AND METHODS

Three patients (mean age 51.3 years; range 43-56) with gastro-entero pancreatic NET (GEP-NET) liver metastases underwent 18F-FDOPA PET/CT-guided RFA. Patients were referred with oligometastatic hepatic-confined disease (1-6 metastases; <3 cm) on 18F-FDOPA PET/CT; poor lesion visualisation on US, CT, and MR; and ongoing symptoms. Procedures were performed in an interventional PET/CT scanner under general anaesthesia using a split-dose protocol. Lesion characteristics, procedural duration and technical success (accurate probe placement and post-procedural ablation-zone photopaenia), complications, patient and operator dose, and clinical outcomes were evaluated.

RESULTS

Thirteen liver metastases (mean size 11.4 mm, range 8-16) were treated in three patients (two presented with "carcinoid syndrome"). Technical success was 100 % with a mean procedural duration of 173.3 min (range 90-210) and no immediate complications. Mean patient dose was 2844 mGy·cm (range 2104-3686). Operator and radiographer doses were acceptable other than the operator's right hand in the first case (149 µSv); this normalised in the second case. There was no local tumour or extra-hepatic disease progression at mid-term follow-up (mean 12.6 months; range 6-20); however, two cases progressed with new liver metastases at different sites. There was 100 % clinical success (n = 2) in resolving carcinoid syndrome symptoms.

CONCLUSION

18F-FDOPA PET/CT-guided RFA appears technically feasible, safe, and effective in patients with GEP-NETs and low-burden hepatic metastases. Further prospective studies are required to elucidate its precise role in tailored multimodality management of GEP-NET liver metastases.

Image fusion and navigation platforms for percutaneous image-guided interventions

Image-guided interventional procedures, particularly image guided biopsy and ablation, serve an important role in the care of the oncology patient. The need for tumor genomic and proteomic profiling, early tumor response assessment and confirmation of early recurrence are common scenarios that may necessitate successful biopsies of targets, including those that are small, anatomically unfavorable or inconspicuous. As image-guided ablation is increasingly incorporated into interventional oncology practice, similar obstacles are posed for the ablation of technically challenging tumor targets. Navigation tools, including image fusion and device tracking, can enable abdominal interventionalists to more accurately target challenging biopsy and ablation targets. Image fusion technologies enable multimodality fusion and real-time co-displays of US, CT, MRI, and PET/CT data, with navigational technologies including electromagnetic tracking, robotic, cone beam CT, optical, and laser guidance of interventional devices. Image fusion and navigational platform technology is reviewed in this article, including the results of studies implementing their use for interventional procedures. Pre-clinical and clinical experiences to date suggest these technologies have the potential to reduce procedure risk, time, and radiation dose to both the patient and the operator, with a valuable role to play for complex image-guided interventions.

Real-Time In Vivo Characterization of Primary Liver Tumors With Diffuse Optical Spectroscopy During Percutaneous Needle Interventions: Feasibility Study in Woodchucks

OBJECTIVE

This study presents the first in vivo real-time optical tissue characterization during image-guided percutaneous intervention using near-infrared diffuse optical spectroscopy sensing at the tip of a needle. The goal of this study was to indicate transition boundaries from healthy tissue to tumors, namely, hepatic carcinoma, based on the real-time feedback derived from the optical measurements.

MATERIALS AND METHODS

Five woodchucks with hepatic carcinoma were used for this study. The woodchucks were imaged with contrast-enhanced cone beam computed tomography with a flat panel detector C-arm system to visualize the carcinoma in the liver. In each animal, 3 insertions were performed, starting from the skin surface toward the hepatic carcinoma under image guidance. In 2 woodchucks, each end point of the insertion was confirmed with pathologic examination of a biopsy sample. While advancing the needle in the animals under image guidance such as fluoroscopy overlaid with cone beam computed tomography slice and ultrasound, optical spectra were acquired at the distal end of the needles. Optical tissue characterization was determined by translating the acquired optical spectra into clinical parameters such as blood, water, lipid, and bile fractions; tissue oxygenation levels; and scattering amplitude related to tissue density. The Kruskal-Wallis test was used to study the difference in the derived clinical parameters from the measurements performed within the healthy tissue and the hepatic carcinoma. Kurtoses were calculated to assess the dispersion of these parameters within the healthy and carcinoma tissues.

RESULTS

Blood and lipid volume fractions as well as tissue oxygenation and reduced scattering amplitude showed to be significantly different between the healthy part of the liver and the hepatic carcinoma (P < 0.05) being higher in normal liver tissue. A decrease in blood and lipid volume fractions and tissue oxygenation as well as an increase in scattering amplitude were observed when the tip of the needle crossed the margin from the healthy liver tissue to the carcinoma. The kurtosis for each derived clinical parameter was high in the hepatic tumor as compared with that in the healthy liver indicating intracarcinoma variability.

CONCLUSIONS

Tissue blood content, oxygenation level, lipid content, and tissue density all showed significant differences when the needle tip was guided from the healthy tissue to the carcinoma and can therefore be used to identify tissue boundaries during percutaneous image-guided interventions.

Cone beam computed tomography images fusion in predicting lung ablation volumes: a feasibility study

BACKGROUND

Recently different software with the ability to plan ablation volumes have been developed in order to minimize the number of attempts of positioning electrodes and to improve a safe overall tumor coverage.

PURPOSE

To assess the feasibility of three-dimensional cone beam computed tomography (3D CBCT) fusion imaging with "virtual probe" positioning, to predict ablation volume in lung tumors treated percutaneously.

MATERIAL AND METHODS

Pre-procedural computed tomography contrast-enhanced scans (CECT) were merged with a CBCT volume obtained to plan the ablation. An offline tumor segmentation was performed to determine the number of antennae and their positioning within the tumor. The volume of ablation obtained, evaluated on CECT performed after 1 month, was compared with the pre-procedural predicted one. Feasibility was assessed on the basis of accuracy evaluation (visual evaluation [VE] and quantitative evaluation [QE]), technical success (TS), and technical effectiveness (TE).

RESULTS

Seven of the patients with lung tumor treated by percutaneous thermal ablation were selected and treated on the basis of the 3D CBCT fusion imaging. In all cases the volume of ablation predicted was in accordance with that obtained. The difference in volume between predicted ablation volumes and obtained ones on CECT at 1 month was 1.8 cm(3) (SD ± 2, min. 0.4, max. 0.9) for MW and 0.9 cm(3) (SD ± 1.1, min. 0.1, max. 0.7) for RF.

CONCLUSION

Use of pre-procedural 3D CBCT fusion imaging could be useful to define expected ablation volumes. However, more patients are needed to ensure stronger evidence.

Comparative evaluation of three-dimensional Gd-EOB-DTPA-enhanced MR fusion imaging with CT fusion imaging in the assessment of treatment effect of radiofrequency ablation of hepatocellular carcinoma

PURPOSE

To assess the feasibility of fusion of pre- and post-ablation gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-DTPA-MRI) to evaluate the effects of radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC), compared with similarly fused CT images

PATIENTS AND METHODS

This retrospective study included 67 patients with 92 HCCs treated with RFA. Fusion images of pre- and post-RFA dynamic CT, and pre- and post-RFA Gd-EOB-DTPA-MRI were created, using a rigid registration method. The minimal ablative margin measured on fusion imaging was categorized into three groups: (1) tumor protruding outside the ablation zone boundary, (2) ablative margin 0-<5.0 mm beyond the tumor boundary, and (3) ablative margin ≥5.0 mm beyond the tumor boundary. The categorization of minimal ablative margins was compared between CT and MR fusion images.

RESULTS

In 57 (62.0%) HCCs, treatment evaluation was possible both on CT and MR fusion images, and the overall agreement between them for the categorization of minimal ablative margin was good (κ coefficient = 0.676, P < 0.01). MR fusion imaging enabled treatment evaluation in a significantly larger number of HCCs than CT fusion imaging (86/92 [93.5%] vs. 62/92 [67.4%], P < 0.05).

CONCLUSIONS

Fusion of pre- and post-ablation Gd-EOB-DTPA-MRI is feasible for treatment evaluation after RFA. It may enable accurate treatment evaluation in cases where CT fusion imaging is not helpful.

Paediatric musculoskeletal interventional radiology

Interventional radiology technique is now well established and widely used in the adult population. Through minimally invasive procedures, it increasingly replaces surgical interventions that involve higher percentages of invasiveness and, consequently, of morbidity and mortality. For these advantageous reasons, interventional radiology in recent years has spread to the paediatric age as well. The aim of this study was to review the literature on the development, use and perspectives of these procedures in the paediatric musculoskeletal field. Several topics are covered: osteomuscle neoplastic malignant and benign pathologies treated with invasive diagnostic and/or therapeutic procedures such as radiofrequency ablation in the osteoid osteoma; invasive and non-invasive procedures in vascular malformations; treatment of aneurysmal bone cysts; and role of interventional radiology in paediatric inflammatory and rheumatic inflammations. The positive results that have been generated with interventional radiology procedures in the paediatric field highly encourage both the development of new ad hoc materials, obviously adapted to young patients, as well as the improvement of such techniques, in consideration of the fact that childrens' pathologies do not always correspond to those of adults. In conclusion, as these interventional procedures have proven to be less invasive, with lower morbidity and mortality rates as well, they are becoming a viable and valid alternative to surgery in the paediatric population.

Clinical experience with cone-beam CT navigation for tumor ablation

PURPOSE

To describe clinical use and potential benefits of cone-beam computed tomography (CT) navigation to perform image-guided percutaneous tumor ablation.

MATERIALS AND METHODS

All ablations performed between February 2011 and February 2013 using cone-beam CT navigation were included. There were 16 patients who underwent 20 ablations for 29 lesions. Cone-beam CT ablation planning capabilities include multimodality image fusion and tumor segmentation for visualization, depiction of the predicted ablation zones for intraprocedural planning, and segmentation of the ablated area for immediate verification after treatment. Number and purpose of cone-beam CT scans were examined. The initial ablation plan, defined as number of probes and duration of energy delivery, was recorded for the 20 of the 29 lesions ablated. Technical success and local recurrences were recorded. Primary and secondary effectiveness rates were calculated.

RESULTS

Image fusion was used for 16 lesions, and intraprocedural ultrasound was used for 4 lesions. Of the 20 ablations, where the ablation plans were recorded, there was no deviation from the plan in 14 ablations. In the remaining 6 ablations, iterative planning was needed for complete tumor coverage. An average of 8.7 cone-beam CT scans ± 3.2 were performed per procedure, including 1.3 ± 0.5 for tumor segmentation and planning, 1.7 ± 0.7 for probe position confirmation, and 3.9 ± 2 to ensure complete coverage. Mean follow-up time was 18.6 months ± 6.5. Ablations for 28 of 29 lesions were technically successful (96.5%). Of ablations performed with curative intent, technical effectiveness at 1 month was 25 of 26 lesions (96.1%) and 22 of 26 lesions (84.6%) at last follow-up. Local tumor progression was observed in 11.5% (3 of 26 lesions).

CONCLUSIONS

Cone-beam CT navigation may add information to assist and improve ablation guidance and monitoring.

Initial Experience of Utilizing Real-Time Intra-Procedural PET/CT Biopsy

OBJECTIVES

Nonreal-time Positron Emission Tomography/Computed Tomography (PET/CT) biopsies that use the image co-registration of a prior PET with an intra-procedural CT have been reported. The aim of this study was to report the initial experience of performing real-time intra-procedural PET/CT-guided biopsies.

MATERIALS AND METHODS

All patients (n = 4) had a prior PET/CT examination of the concerning lesion and no significant CT correlate. On the day of the biopsy, 5 mCi of 18F-fluorodeoxyglucose (FDG) or NaF18 was intravenously injected. After 60 min of biodistribution of the molecular probe, PET/CT images were obtained in a limited one bed position over the region of the concerning lesion to be biopsied.

RESULTS

One patient had a mesenteric mass and the other three had bone lesions, one located in the rib and two in the iliac bone. The pathology report revealed that two lesions (50%) were malignant and two lesions (50%) were benign. The results of the biopsy changed management in all cases. There was 0% complication rate.

CONCLUSIONS

No additional software or hardware is required to perform real-time intra-procedural PET/CT-guided biopsies. It can optimize the yield, especially in cases where there are no anatomical abnormalities. Real-time intra-procedural PET/CT biopsy may have benefits over conventional biopsy techniques in terms of accuracy.

C-arm cone-beam computed tomography in interventional oncology: technical aspects and clinical applications

C-arm cone-beam computed tomography (CBCT) is a new imaging technology integrated in modern angiographic systems. Due to its ability to obtain cross-sectional imaging and the possibility to use dedicated planning and navigation software, it provides an informed platform for interventional oncology procedures. In this paper, we highlight the technical aspects and clinical applications of CBCT imaging and navigation in the most common loco-regional oncological treatments.

Image fusion during vascular and nonvascular image-guided procedures

Image fusion may be useful in any procedure where previous imaging such as positron emission tomography, magnetic resonance imaging, or contrast-enhanced computed tomography (CT) defines information that is referenced to the procedural imaging, to the needle or catheter, or to an ultrasound transducer. Fusion of prior and intraoperative imaging provides real-time feedback on tumor location or margin, metabolic activity, device location, or vessel location. Multimodality image fusion in interventional radiology was initially introduced for biopsies and ablations, especially for lesions only seen on arterial phase CT, magnetic resonance imaging, or positron emission tomography/CT but has more recently been applied to other vascular and nonvascular procedures. Two different types of platforms are commonly used for image fusion and navigation: (1) electromagnetic tracking and (2) cone-beam CT. Both technologies would be reviewed as well as their strengths and weaknesses, indications, when to use one vs the other, tips and guidance to streamline use, and early evidence defining clinical benefits of these rapidly evolving, commercially available and emerging techniques.

Image-guided nerve cryoablation for post-thoracotomy pain syndrome

Chronic post-thoracotomy pain syndrome (PTPS) can cause significant patient distress and is frequently difficult to manage. Percutaneous intercostal nerve (ICN) cryoablation by palpation of surface landmarks can be risky, as inaccurate probe placement can lead to hemo- or pneumothorax. Experience with image-guided ICN cryoablation with treatment planning and device navigation is limited. A patient with intractable PTPS was treated with ICN cryoablation under cone-beam computed tomography guidance with software-assisted needle trajectory planning and ablation zone simulation. This procedure provided the patient ~8 weeks of relief. This case demonstrated that ICN cryoablation is feasible under image guidance with device navigation and ablation simulation and may result in a few months of pain relief in cases of intractable PTPS.

Percutaneous punctures with MR imaging guidance: comparison between MR imaging-enhanced fluoroscopic guidance and real-time MR Imaging guidance

PURPOSE

To evaluate and compare the technical accuracy and feasibility of magnetic resonance (MR) imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance for percutaneous puncture procedures in phantoms and animals.

MATERIALS AND METHODS

The experimental protocol was approved by the institutional animal care and use committee. Punctures were performed in phantoms, aiming for markers (20 each for MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance), and pigs, aiming for anatomic landmarks (10 for MR imaging-enhanced fluoroscopic guidance and five for MR imaging guidance). To guide the punctures, T1-weighted three-dimensional (3D) MR images of the phantom or pig were acquired. Additional axial and coronal T2-weighted images were used to visualize the anatomy in the animals. For MR imaging-enhanced fluoroscopic guidance, phantoms and pigs were transferred to the fluoroscopic system after initial MR imaging and C-arm computed tomography (CT) was performed. C-arm CT and MR imaging data sets were coregistered. Prototype navigation software was used to plan a puncture path with use of MR images and to superimpose it on fluoroscopic images. For real-time MR imaging, an interventional MR imaging prototype for interactive real-time section position navigation was used. Punctures were performed within the magnet bore. After completion, 3D MR imaging was performed to evaluate the accuracy of insertions. Puncture durations were compared by using the log-rank test. The Mann-Whitney U test was applied to compare the spatial errors.

RESULTS

In phantoms, the mean total error was 8.6 mm ± 2.8 with MR imaging-enhanced fluoroscopic guidance and 4.0 mm ± 1.2 with real-time MR imaging guidance (P < .001). The mean puncture time was 2 minutes 10 seconds ± 44 seconds with MR imaging-enhanced fluoroscopic guidance and 37 seconds ± 14 with real-time MR imaging guidance (P < .001). In the animal study, a tolerable distance (<1 cm) between target and needle tip was observed for both MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance. The mean total error was 7.7 mm ± 2.4 with MR imaging-enhanced fluoroscopic guidance and 7.9 mm ± 4.9 with real-time MR imaging guidance (P = .77). The mean puncture time was 5 minutes 43 seconds ± 2 minutes 7 seconds with MR imaging-enhanced fluoroscopic guidance and 5 minutes 14 seconds ± 2 minutes 25 seconds with real-time MR imaging guidance (P = .68).

CONCLUSION

Both MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance demonstrated reasonable and similar accuracy in guiding needle placement to selected targets in phantoms and animals.