3D-Printing of Arteriovenous Malformations for Radiosurgical Treatment: Pushing Anatomy Understanding to Real Boundaries

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: neurosurgical and otolaryngologic conditions

BACKGROUND

Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG.

CONCLUSIONS

This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions.

A patient-specific multi-modality abdominal aortic aneurysm imaging phantom

Purpose

Multimodality imaging of the vascular system is a rapidly growing area of innovation and research, which is increasing with awareness of the dangers of ionizing radiation. Phantom models that are applicable across multiple imaging modalities facilitate testing and comparisons in pre-clinical studies of new devices. Additionally, phantom models are of benefit to surgical trainees for gaining experience with new techniques. We propose a temperature-stable, high-fidelity method for creating complex abdominal aortic aneurysm phantoms that are compatible with both radiation-based, and ultrasound-based imaging modalities, using low cost materials.

Methods

Volumetric CT data of an abdominal aortic aneurysm were acquired. Regions of interest were segmented to form a model compatible with 3D printing. The novel phantom fabrication method comprised a hybrid approach of using 3D printing of water-soluble materials to create wall-less, patient-derived vascular structures embedded within tailored tissue-mimicking materials to create realistic surrounding tissues. A non-soluble 3-D printed spine was included to provide a radiological landmark.

Results

The phantom was found to provide realistic appearances with intravascular ultrasound, computed tomography and transcutaneous ultrasound. Furthermore, the utility of this phantom as a training model was demonstrated during a simulated endovascular aneurysm repair procedure with image fusion.

Conclusion

With the hybrid fabrication method demonstrated here, complex multimodality imaging patient-derived vascular phantoms can be successfully fabricated. These have potential roles in the benchtop development of emerging imaging technologies, refinement of novel minimally invasive surgical techniques and as clinical training tools.

Additive Fabrication of a Vascular 3D Phantom for Stereotactic Radiosurgery of Arteriovenous Malformations

In this study, an efficient methodology for manufacturing a realistic three-dimensional (3D) cerebrovascular phantom resembling a brain arteriovenous malformation (AVM) for applications in stereotactic radiosurgery is presented. The AVM vascular structure was 3D reconstructed from brain computed tomography (CT) data acquired from a patient. For the phantom fabrication, stereolithography was used to produce the AVM model and combined with silicone casting to mimic the brain parenchyma surrounding the vascular structure. This model was made with tissues-equivalent materials for radiology. The hollow vascular system of the phantom was filled with a contrast agent usually employed on patients for CT scans. The radiological response of the phantom was tested and compared with the one of the clinical case. The constructed model demonstrated to be a very accurate physical representation of the AVM and its vasculature and good morphological consistency was observed between the model and the patient-specific source anatomy. These results suggest that the proposed method has potential to be used to fabricate patient-specific phantoms for neurovascular radiosurgery applications and medical research.

Removal of Double Cavernous Angioma of the Frontal Lobe using a Three-Dimensional Printed Model: A Case Report

Cerebral cavernous angiomas are vascular anomalies with dilated spaces. We report the case of rare double cavernous angiomas causing higher brain dysfunction. A 74-year-old man exhibited cognitive dysfunction. Magnetic resonance imaging showed two tumors with hemorrhage in the left frontal lobe. Preoperative diagnosis was hemorrhage caused by cavernous angiomas. A 3D model of the double cavernous angioma was made to confirm their association with cortical veins and tumors. Tumors were removed using a single small corticotomy. This is the first report of a rare double cavernous angioma and the 3D printed model facilitated removal of the tumors.

Three-dimensional printing in radiation oncology: A systematic review of the literature

Purpose/objectives

Three‐dimensional (3D) printing is recognized as an effective clinical and educational tool in procedurally intensive specialties. However, it has a nascent role in radiation oncology. The goal of this investigation is to clarify the extent to which 3D printing applications are currently being used in radiation oncology through a systematic review of the literature.

Materials/methods

A search protocol was defined according to preferred reporting items for systematic reviews and meta‐analyses (PRISMA) guidelines. Included articles were evaluated using parameters of interest including: year and country of publication, experimental design, sample size for clinical studies, radiation oncology topic, reported outcomes, and implementation barriers or safety concerns.

Results

One hundred and three publications from 2012 to 2019 met inclusion criteria. The most commonly described 3D printing applications included quality assurance phantoms (26%), brachytherapy applicators (20%), bolus (17%), preclinical animal irradiation (10%), compensators (7%), and immobilization devices (5%). Most studies were preclinical feasibility studies (63%), with few clinical investigations such as case reports or series (13%) or cohort studies (11%). The most common applications evaluated within clinical settings included brachytherapy applicators (44%) and bolus (28%). Sample sizes for clinical investigations were small (median 10, range 1–42). A minority of articles described basic or translational research (11%) and workflow or cost evaluation studies (3%). The number of articles increased over time (P < 0.0001). While outcomes were heterogeneous, most studies reported successful implementation of accurate and cost‐effective 3D printing methods.

Conclusions

Three‐dimensional printing is rapidly growing in radiation oncology and has been implemented effectively in a diverse array of applications. Although the number of 3D printing publications has steadily risen, the majority of current reports are preclinical in nature and the few clinical studies that do exist report on small sample sizes. Further dissemination of ongoing investigations describing the clinical application of developed 3D printing technologies in larger cohorts is warranted.

A small 3D-printing model of macroadenomas for endoscopic endonasal surgery

PURPOSE

This paper examines the application of 3D printing technology in the endoscopic endonasal approach for the treatment of macroadenomas.

METHODS

We have retrospectively analysed 20 patients who diagnosed with macroadenoma underwent endoscopic transsphenoidal surgery in Wuhan Union hospital from January 2017 to May 2017. Among the 20 patients, 10 patients received the service of 3D printing technology preoperatively. The data of 3D processing and clinical result were recorded for further evaluation.

RESULTS

The 10 patients who received the service had a successful 3D printed model of their tumors, it shows the anatomy of sphenoid sinus, tumor location which were in good agreement with our intraoperative observations. The 10 patients who received the service had a less operation time (127.0 ± 15.53 vs. 143.40 ± 17.89), blood loss (159.90 ± 12.31 vs. 170.00 ± 29.06) and less postoperative complication rate (20% vs. 40%). the design time of the 3D images varies 2 h 10 min to 4 h 32 min. the printing time of the 3D models varies 10 h 12 min to 22 h 34 min.

CONCLUSIONS

The use of 3D printing technology has unquestionable potential applications to endoscopic endonasal approach for macroadenomas, in particular reflecting the complicated anatomy of sphenoid sinus and tumor location. Owing to the advantages of 3D printing technology, it may help the patients get a good prognosis.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

3D Printing is a Transformative Technology in Congenital Heart Disease

Survival in congenital heart disease has steadily improved since 1938, when Dr. Robert Gross successfully ligated for the first time a patent ductus arteriosus in a 7-year-old child. To continue the gains made over the past 80 years, transformative changes with broad impact are needed in management of congenital heart disease. Three-dimensional printing is an emerging technology that is fundamentally affecting patient care, research, trainee education, and interactions among medical teams, patients, and caregivers. This paper first reviews key clinical cases where the technology has affected patient care. It then discusses 3-dimensional printing in trainee education. Thereafter, the role of this technology in communication with multidisciplinary teams, patients, and caregivers is described. Finally, the paper reviews translational technologies on the horizon that promise to take this nascent field even further.

Application of Time-Resolved 3D Digital Subtraction Angiography to Plan Cerebral Arteriovenous Malformation Radiosurgery

BACKGROUND AND PURPOSE

Time-resolved 3D-DSA (4D-DSA) enables viewing vasculature from any desired angle and time frame. We investigated whether these advantages may facilitate treatment planning and the feasibility of using 4D-DSA as a single imaging technique in AVM/dural arteriovenous fistula radiosurgery.

MATERIALS AND METHODS

Twenty consecutive patients (8 dural arteriovenous fistulas and 12 AVMs; 13 men and 7 women; mean age, 45 years; range, 18-64 years) who were scheduled for gamma knife radiosurgery were recruited (November 2014 to October 2015). An optimal volume of reconstructed time-resolved 3D volumes that defines the AVM nidus/dural arteriovenous fistula was sliced into 2D-CT-like images. The original radiosurgery treatment plan was overlaid retrospectively. The registration errors of stereotactic 4D-DSA were compared with those of integrated stereotactic imaging. AVM/dural arteriovenous fistula volumes were contoured, and disjoint and conjoint components were identified. The Wilcoxon signed rank test and the Wilcoxon rank sum test were adopted to evaluate registration errors and contoured volumes of stereotactic 4D-DSA and integration of stereotactic MR imaging and stereotactic 2D-DSA.

RESULTS

Sixteen of 20 patients were successfully registered in Advanced Leksell GammaPlan Program. The registration error of stereotactic 4D-DSA was smaller than that of integrated stereotactic imaging (P = .0009). The contoured AVM volume of 4D-DSA was smaller than that contoured on the integration of MR imaging and 2D-DSA, while major inconsistencies existed in cases of dural arteriovenous fistula (P = .042 and 0.039, respectively, for measurements conducted by 2 authors).

CONCLUSIONS

Implementation of stereotactic 4D-DSA data for gamma knife radiosurgery for brain AVM/dural arteriovenous fistula is feasible. The ability of 4D-DSA to demonstrate vascular morphology and hemodynamics in 4 dimensions potentially reduces the target volumes of irradiation in vascular radiosurgery.