Aneurysmal subarachnoid hemorrhage diagnosis with computed tomographic angiography and OsiriX

Virtual preoperative planning and 3D tumoral reconstruction with Horos open-source software

Background

Presurgical three-dimensional (3D) reconstructions allow spatial localization of cerebral lesions and their relationship with adjacent anatomical structures for optimal surgical resolution. The purpose of the present article is to present a method of virtual preoperative planning aiming to enhance 3D comprehension of neurosurgical pathologies using free DICOM image viewers.

Case Description

We describe the virtual presurgical planning of a 61-year-old female presenting a cerebral tumor. 3D reconstructions were created with the "Horos^®" Digital Imaging and Communications in Medicine viewer, utilizing images obtained from contrast-enhanced brain magnetic resonance imaging and computed tomography. The tumor and adjacent relevant structures were identified and delimited. A sequential virtual simulation of the surgical stages for the approach was performed with the identification of local gyral and vascular patterns of the cerebral surface for posterior intraoperative recognition. Through virtual simulation, an optimal approach was gained. Accurate localization and complete removal of the lesion were achieved during the surgical procedure. Virtual presurgical planning with open-source software can be utilized for supratentorial pathologies in both urgent and elective cases. Virtual recognition of vascular and cerebral gyral patterns is helpful reference points for intraoperative localization of lesions lacking cortical expression, allowing less invasive corticotomies.

Conclusion

Digital manipulation of cerebral structures can increase anatomical comprehension of neurosurgical lesions to be treated. 3D interpretation of neurosurgical pathologies and adjacent anatomical structures is essential for developing an effective and safe surgical approach. The described technique is a feasible and accessible option for presurgical planning.

Simulation of surgery for supratentorial gliomas in virtual reality using a 3D volume rendering technique: a poor man's neuronavigation

OBJECTIVE

Different techniques of performing image-guided neurosurgery exist, namely, neuronavigation systems, intraoperative ultrasound, and intraoperative MRI, each with its limitations. Except for ultrasound, other methods are expensive. Three-dimensional virtual reconstruction and surgical simulation using 3D volume rendering (VR) is an economical and excellent technique for preoperative surgical planning and image-guided neurosurgery. In this article, the authors discuss several nuances of the 3D VR technique that have not yet been described.

METHODS

The authors included 6 patients with supratentorial gliomas who underwent surgery between January 2019 and March 2021. Preoperative clinical data, including patient demographics, preoperative planning details (done using the VR technique), and intraoperative details, including relevant photos and videos, were collected. RadiAnt software was used for generating virtual 3D images using the VR technique on a computer running Microsoft Windows.

RESULTS

The 3D VR technique assists in glioma surgery with a preoperative simulation of the skin incision and craniotomy, virtual cortical surface marking and navigation for deep-seated gliomas, preoperative visualization of morbid cortical surface and venous anatomy in surfacing gliomas, identifying the intervenous surgical corridor in both surfacing and deep-seated gliomas, and pre- and postoperative virtual 3D images highlighting the exact spatial geometric residual tumor location and extent of resection for low-grade gliomas (LGGs).

CONCLUSIONS

Image-guided neurosurgery with the 3D VR technique using RadiAnt software is an economical, easy-to-learn, and user-friendly method of simulating glioma surgery, especially in resource-constrained countries where expensive neuronavigation systems are not readily available. Apart from cortical sulci/gyri anatomy, FLAIR sequences are ideal for the 3D visualization of nonenhancing diffuse LGGs using the VR technique. In addition to cortical vessels (especially veins), contrast MRI sequences are perfect for the 3D visualization of contrast-enhancing high-grade gliomas.

The venous delay phenomenon in computed tomography angiography: a novel imaging outcome predictor for poor cerebral perfusion after severe aneurysmal subarachnoid hemorrhage

OBJECTIVE

Diverse treatment results are observed in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH). Significant initial perfusion compromise is thought to predict a worse treatment outcome, but this has scant support in the literature. In this cohort study, the authors correlate the treatment outcomes with a novel poor-outcome imaging predictor representing impaired cerebral perfusion on initial CT angiography (CTA).

METHODS

The authors reviewed the treatment results of 148 patients with poor-grade aSAH treated at a single tertiary referral center between 2007 and 2016. Patients with the "venous delay" phenomenon on initial CTA were identified. The outcome assessments used the modified Rankin Scale (mRS) at the 3rd month after aSAH. Factors that may have had an impact on outcome were retrospectively analyzed.

RESULTS

Compared with previously identified outcome predictors, the venous delay phenomenon on initial CTA was found to have the strongest correlation with posttreatment outcomes on both univariable (p < 0.0001) and multivariable analysis (OR 4.480, 95% CI 1.565-12.826; p = 0.0052). Older age and a higher Hunt and Hess grade at presentation were other factors that were associated with poor outcome, defined as an mRS score of 3 to 6.

CONCLUSIONS

The venous delay phenomenon on initial CTA can serve as an imaging predictor for worse functional outcome and may aid in decision making when treating patients with poor-grade aSAH.

OsiriX software as a preoperative planning tool in cranial neurosurgery: A step-by-step guide for neurosurgical residents

Background:

OsiriX (Pixmeo, Switzerland) is an open-source Digital Imaging and Communications in Medicine (DICOM) viewer that is gaining more and more attention in the neurosurgical community because of its user-friendly interface, powerful three-dimensional (3D) volumetric rendering capabilities, and various options for data integration. This paper presents in detail the use of OsiriX software as a preoperative planning tool in cranial neurosurgery.

Methods:

In January 2013, OsiriX software was introduced into our clinical practice as a preoperative planning tool. Its capabilities are being evaluated on an ongoing basis in routine elective cranial cases.

Results:

The program has proven to be highly effective at volumetrically representing data from radiological examinations in 3D. Among its benefits in preoperative planning are simulating the position and exact location of the lesion in 3D, tailoring the skin incision and craniotomy bone flap, enhancing the representation of normal and pathological anatomy, and aiding in planning the reconstruction of the affected area.

Conclusion:

OsiriX is a useful tool for preoperative planning and visualization in neurosurgery. The software greatly facilitates the surgeon's understanding of the relationship between normal and pathological anatomy and can be used as a teaching tool.

Three-dimensional image reconstruction with free open-source OsiriX software in video-assisted thoracoscopic lobectomy and segmentectomy

OBJECTIVE

The aim of this retrospective study was to evaluate the practice and the feasibility of Osirix, a free and open-source medical imaging software, in performing accurate video-assisted thoracoscopic lobectomy and segmentectomy.

METHODS

From July 2014 to April 2016, 63 patients received anatomical video-assisted thoracoscopic surgery (VATS), either lobectomy or segmentectomy, in our department. Three-dimensional (3D) reconstruction images of 61 (96.8%) patients were preoperatively obtained with contrast-enhanced computed tomography (CT). Preoperative resection simulations were accomplished with patient-individual reconstructed 3D images. For lobectomy, pulmonary lobar veins, arteries and bronchi were identified meticulously by carefully reviewing the 3D images on the display. For segmentectomy, the intrasegmental veins in the affected segment for division and the intersegmental veins to be preserved were identified on the 3D images. Patient preoperative characteristics, surgical outcomes and postoperative data were reviewed from a prospective database.

RESULTS

The study cohort of 63 patients included 33 (52.4%) men and 30 (47.6%) women, of whom 46 (73.0%) underwent VATS lobectomy and 17 (27.0%) underwent VATS segmentectomy. There was 1 conversion from VATS lobectomy to open thoracotomy because of fibrocalcified lymph nodes. A VATS lobectomy was performed in 1 case after completing the segmentectomy because invasive adenocarcinoma was detected by intraoperative frozen-section analysis. There were no 30-day or 90-day operative mortalities CONCLUSIONS: The free, simple, and user-friendly software program Osirix can provide a 3D anatomic structure of pulmonary vessels and a clear vision into the space between the lesion and adjacent tissues, which allows surgeons to make preoperative simulations and improve the accuracy and safety of actual surgery.

Vestibulo-Oral inclination of maxillary and mandibular canines and bicuspids - a CBCT investigation

BACKGROUND

The aim of this retrospective study was to measure tooth and crowns axes of canines, first and second bicuspids of orthodontically untreated subjects with near normal occlusion to: 1. Define norms and reveal potential gender differences and 2. Discuss implications of the findings for orthodontics.

METHODS

The CBCT-datasets of 167 patients, 56 males (mean age 28.63 years ± 11.99 years) and 111 females (mean age 29.72 years ± 11.47 years) were used. Tooth- and crown axes were measured for right and left sides. Normal distribution was evaluated with the Kolmogorov-Smirnov-test. For gender comparison independent t-Tests and for comparison of right and left sides a paired t-Test were used for normally distributed data. For data not following normal distribution for gender comparison the Mann-Whitney-U-Test was used and for data comparing the two sides the Wilcoxon signed rank test was applied. The level of statistical significance was set at p ≤ 0.05.

RESULTS

Measurement of tooth axes revealed buccal inclination for both genders with maximum values for maxillary and mandibular canines. Statistical significant differences were only found for maxillary canines (P = 0.025) and lower second bicuspids (P = 0.016) respectively. Values for crown axes revealed oral inclination for both genders with maximum values for maxillary first bicuspids and in the mandible for first and second bicuspids. No statistical significant differences were found between the genders apart from asymmetry for crown axes for the upper first bicuspids for males (P = 0.006) and females (P < 0.001).

CONCLUSIONS

Our study reveals that irrespective of gender, oral inclination of the crowns of canines and premolars is the norm. The values of the most commonly used bracket prescriptions coincide with the average values found in our investigation. For esthetic reasons modifications of torque values can be considered.

Three dimensional anatomical exploration of the anterior hard palate at the level of the third ruga for the placement of mini-implants--a cone-beam CT study

AIM

The aim of this retrospective investigation was to measure vertical bone thickness on the hard palate, determine areas with adequate bone for the insertion of orthodontic mini-implants (MIs), and provide clinical guidelines for identification of those areas.

MATERIALS AND METHODS

Pre-treatment records of 1007 patients were reviewed by a single examiner. A total of 125 records fulfilled the inclusion criteria and were further investigated. Bone measurements were performed on cone-beam computed tomography scans, at a 90° angle to the bone surface, on 28 predetermined and standardized points on the hard palate. Bone thickness at various areas was associated to clinically identifiable areas on the hard palate by means of pre-treatment plaster models.

RESULTS

Bone thickness ranged between 1.51 and 13.86 mm (total thickness) and 0.33 and 1.65 mm (cortical bone thickness), respectively. Bone thickness was highest in the anterior palate and decreased significantly towards more posterior areas. Plaster model analysis revealed that bone thickness was highest at the level of the third palatal ruga.

CONCLUSIONS

The areas on the anterior palate with adequate bone thickness for successful insertion of orthodontic MI correspond to the region of the third palatal ruga. These results provide stable and clinically identifiable landmarks for the insertion of palatal MIs.