Preoperative Imaging Information Research Articles

Application of a mixed reality device to oral surgery

Mixed reality refers to all technologies that combine real and virtual spaces to create a new space in which real and virtual objects interact in real time. Recently, the development of technology for superimposing three-dimensional computer graphics on real space has been dramatic. This technology has also been applied to oral surgery. This report describes five diverse cases of oral surgery that were treated using the latest mixed reality device (Microsoft®HoloLens2). Case 1 underwent temporomandibular joint mobilization for ankylosis. Case 2 underwent alveolar bone grafting for cheilognathopalatoschisis. Case 3 underwent genioplasty for jaw deformity. Case 4 underwent resection of a mandibular calcifying epithelial odontogenic tumor. Case 5 underwent open reduction and internal fixation for a mandibular fracture. In each case, three-dimensional images were created from the digital imaging and communications in medicine data of computed tomography images using the three-dimensional Slicer software, the images were edited using the Blender software, an application for HoloLens2 created using the Unity software, and HoloLens2 was worn by the surgical assistant to display the three-dimensional image in the surgical field through manual operations. The visibility of the three-dimensional images was good, and preoperative image information could be observed in real time.

Application of Surface Landmarks Combined with Image-Guided Sinus Location in the Retrosigmoid Approach and Their Clinic-Image Relationship Analysis.

Objectives During craniotomy for cerebellopontine angle (CPA) lesions, the exact exposure of the margin of the venous sinuses complex remains an essential but risky part of the procedure. Here, we revealed the exact position of the asterion and sinus complex by combining preoperative image information and intraoperative cranial landmarks, and analyzed their clinic-image relationship. Methods Ninety-four patients who underwent removal of vestibular schwannoma (VS) through retrosigmoid craniotomies were enrolled in the series. To determine the exact location of the sigmoid sinus and the transverse sinus and sigmoid sinus junction (TSSJ), we used preoperative images, such as computed tomography (CT) and/or magnetic resonance imaging (MRI) combined with intraoperative anatomical landmarks. The distance between the asterion and the sigmoid sinus was measured using MRI T1 sequences with gadolinium and/or the CT bone window. Results In 94 cases of retrosigmoid craniotomies, the asterion lay an average of 12.71 mm on the posterior to the body surface projection to the TSSJ. Intraoperative cranial surface landmarks were used in combination with preoperative image information to identify the distance from the asterion to the sigmoid sinus at the transverse sinus level, allowing for an appropriate initial burr hole (the margin of the TSSJ). Conclusion By combining intraoperative anatomical landmarks and preoperative image information, the margin of the TSSJ, in particular, the inferior margin of the transverse sinus, can be well and thoroughly identified in the retrosigmoid approach.

Prediction of pathological complete response using radiomics on MRI in patients with breast cancer undergoing neoadjuvant pharmacotherapy.

Neoadjuvant pharmacotherapy is essential for patients with breast cancer who wish to preserve the breast by shrinking the malignant tumor, allowing breast-conserving surgery. It may eliminate cancer cells completely, which is known as pathologic complete response (pCR). Patients with pCR have a lower risk of recurrence. The purpose of this study was to develop a method for predicting patients who achieve pCR by neoadjuvant pharmacotherapy using radiomic features in MR images. Fat-suppressed T2-weighted MR images of 64 cases were identified from the ISPY1 dataset. There were 26 cases of pCR and 38 cases of non-pCR. The image slice with the largest tumor diameter was selected from MR images, and the tumor region was manually segmented. A total of 371 radiomic features were calculated from the tumor region. We selected nine radiomic features using Lasso in this study. A support vector machine (SVM) with nine radiomic features was used for predicting patients with pCR. The result of the ROC analysis showed that the area under the curve of SVM was 0.92 for distinguishing between pCR and non-pCR. Although the input data contain data that were misclassified by SVM, the survival curve classified into the pCR group was at a higher position than the non-pCR group. However, the log-rank test was [Formula: see text]. We developed a method to predict patients with pCR by neoadjuvant pharmacotherapy using noninvasive MR images. The survival curve of patients classified as having pCR by the proposed method was higher than those classified as non-pCR. Since the proposed method predicts patients who achieve pCR by neoadjuvant pharmacotherapy, it enhances the value of preoperative image information.

Preoperative imaging evaluation of the absolute indication criteria for endoscopic submucosal dissection in early gastric cancer patients.

IntroductionGastric cancer (GC) is a common malignant tumor with a high mortality rate.AimTo determine the accuracy of preoperative imaging information obtained from the combined use of general gastroscopy (GS), endoscopic ultrasonography (EUS), and multi-detector computed tomography (MDCT) regarding absolute indication of endoscopic submucosal dissection (ESD) in early gastric cancer (EGC).Material and methodsThe relationship between clinical features of 794 EGC patients and lymph node metastasis (LNM) was analyzed. Multivariate logistic regression analysis was used to investigate the risk factors for LNM. Additionally, the accuracy of diagnosis of imaging techniques for ESD indications was determined by receiver operating characteristic (ROC) analysis.ResultsData showed that tumor size > 2 cm (p = 0.0071), T1b stage (p < 0.0001), undifferentiated histology (p < 0.0001), and vascular invasion (p = 0.0007) were independent risk factors for LNM in patients with EGC. Indications for ESD have a specificity of 100% for the diagnosis of patients with LNM. Additionally, the diagnostic efficacy of the use of GS, EUS, and MDCT in identifying node positive status, T1a disease, tumor size ≤ 2 cm, and ulceration was found to be moderate with area under the curve (AUC) of receiver operating characteristic curve (ROC) of 0.71, 0.64, 0.72, and 0.68, respectively. Furthermore, the use of imaging techniques for overall indication criteria for ESD had a moderate utility value with an AUC of 0.71.ConclusionsOur data suggested that, based on the combined use of GS, EUS, and MDCT, a high specificity of patient selection for ESD treatment can be achieved.

Evaluation of vascular invasion in patients with musculoskeletal tumors of lower extremities: use of time-resolved 3D MR angiography at 3-T.

Background Time-resolved angiography with stochastic trajectories (TWIST) sequence makes considerable progress in temporal and spatial resolution, which presents high potential in evaluation of vascular diseases. Purpose To assess magnetic resonance imaging (MRI) using TWIST MR angiography (MRA) sequence in the assessment of vascular invasion for bone and soft-tissue tumors in comparison to computed tomography angiography (CTA) as the reference standard. Material and Methods Thirty-three patients with lower extremity musculoskeletal tumors were imaged with conventional MR and TWIST MRA. CTA was performed 48 h later. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the femoral artery were calculated. Vascular invasion as determined by MRA and CTA was separately analyzed. Vascular invasion by MRA and CTA were analyzed with kappa coefficients to determine agreement between the imaging methods. Results Seven cases of bone and 26 cases of soft tissue tumors were examined. SNR and CNR of the femoral artery were excellent for TWIST MRA (mean ± SD values of 317 ± 80 and 276 ± 76, respectively). Based on the TWIST sequence, the vessels were free of tumor in 16 cases. Vascular displacement was found in 11 cases and vascular stenosis in six cases. The MRA findings conflicted with CTA findings in only one case. The kappa value was 0.953 ( P < 0.01). In five cases, vascular malformations were found with TWIST MRA but not CTA. Conclusion TWIST MRA enables accurate delineation of anatomical structures and tumor arterial involvement, providing reliable preoperative imaging information with respect to lower extremity musculoskeletal tumors.

Abstract P1-01-22: Use of Freehand SPECT for 3D Navigated Radio-Guided Axillary Sentinel Lymph Node Biopsy and Quality Assurance in Breast Cancer Surgery

Abstract Background: The sentinel lymph node (SLN) concept in breast cancer is an integral standard of care. However, several practical issues have been raised preventing proper identification of the sentinel node in certain clinical scenarios. Moreover, the criteria for definition of sentinel node have recently been questioned, including the value of dynamic information or the value of preoperative lymphoscintigraphy. The problems behind some of these questions rely on the impracticability to incorporate the preoperative imaging information into the operative procedure of sentinel lymph node biopsy (SLNB). Methods: For the freehand SPECT (fhSPECT, SurgicEye Germany) acquisition a gamma probe system and an infrared optical tracking system were combined in one system including a data processing unit in order to acquire the readouts of the probe and the position synchronously, process the readings into a 3D image and display them for the user. To date, 20 patients with invasive breast cancer undergoing SLNB were recruited and scanned intraoperatively using fhSPECT before excision of SLNs. The localization of SLNs with fhSPECT was compared to the position of SLNs detected using gamma probe and blue dye. FhSPECT was further used to prove the excision of the SLN postoperatively. Preoperative planar scintigraphy was used as a reference. Results: Preoperatively, 38 SLNs were mapped with conventional scintigraphy. In the pre-excision scan (performed in 19 of 20 patients) fhSPECT managed to map all but 3 SLNs in the identical position as compared to node location at planar scintigrams (34/37). Only in 1 patient fhSPECT did not find any SLN in the pre-excision scan. Gamma probe failed to detect any SLNs in 2 patients and mapped in total 30 of 38 nodes. 28 SLNs were resected and confirmed to be radioactive ex-vivo. fhSPECT detected 11 SLNs in 11 patients after primary SLN excision. In 4 cases additionally detected nodes were resected and confirmed to be radioactive, while in 7 cases harvesting of the additionally detected node was discarded as higher uptake SLNs had been removed already. In the remaining 9 patients no residual radioactivity was found in the axilla. Pre-excision fhSPECT acquisitions took approx. 3.1min (SD, 1.1min) while post-excision scans took 3.2min (SD, 0.9min). The surgical procedure was extended by 12min (6min before incision and 6min after excision of SLNs). Discussion: Intraoperative 3D imaging with fhSPECT for lymphatic mapping in breast cancer patients is feasible. Identification of the SLN can be repeated at any time during surgery to guide proper and precise resection of the sentinel node(s). For quality assurance the system can digitally document that all SLNs have been successfully removed. The freehand SPECT provides also new options concerning the above stated controversies in the principal sentinel lymph node concept. Controlled studies using 3D intraoperative imaging could help to clarify many of the discussed issues, including the role of lymphatic uptake on selecting the nodes for surgical resection. Also, the option to transfer dynamic information from preoperative imaging into the OR or the possibility to skip preoperative imaging bears additional advantages over the standard procedure. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-22.

Imaging the cerebrovascular tree in the cadaveric head for planning surgical strategy.

The objective of the study was to identify whether an integration of cadaveric dissections with preoperative imaging information may enable a better understanding of pathological anatomy, especially vascular lesions, and thus allow for greater precision in surgical planning. We selected a computed tomographic contrast agent and experimentally determined the proportion of it that could mix compatibly with the silicone compound. The resultant mixture was injected into the cerebrovascular systems of six fresh human cadaveric heads. The specimens underwent computed tomography for the purpose of digital virtual exposures in parallel with laboratory dissections performed on these specimens. The 1:8 ratio of contrast agent to silicone rubber was determined to be appropriate for both computed tomography and subsequent laboratory dissection of the specimens. The blood vessels in computed tomographic scans demonstrated a higher attenuation than surrounding soft tissues. The opacity consistency of the injected vessels was a critical parameter for a clear three-dimensional rendering of the vascular structures in the natural surroundings of the skull base. Static and dynamic three-dimensional images of the cadaveric vascular tree were obtained as viewed through surgical corridors of various skull base approaches. We demonstrated a new cadaveric preparation model for imaging and dissection. This model allows for static and dynamic three-dimensional examination of the surgical anatomy from a neurosurgeon's perspective. It may facilitate the study of cerebrovascular system morphology/pathology in relation to the skull base as a tool for surgical planning.

Endovascular repair of descending thoracic aortic aneurysms: an early experience with intermediate-term follow-up

Purpose: The purpose of this study was to report an initial experience with the endovascular repair of descending thoracic aortic aneurysm. Complications and intermediate-term morphologic changes were identified with the intent of altering patient selection and device design. Methods: Endografts were placed into 25 patients at high-risk for conventional surgical repair over a 3½–year period. Devices were customized on the basis of preoperative imaging information. Follow-up computed tomography scans were obtained at 1, 3, 6, and 12 months and yearly thereafter. Additional interventions occurred in the setting of endoleaks, migration, and aneurysm growth. Results: The overall 30-day mortality rate was 20% (12.5% for elective cases; 33% for emergent cases). There were 3 conversions to open repair. Neurologic deficits developed in 3 patients; 1 insult resulted in permanent paraplegia. Neurologic deficits were associated with longer endografts ( P = .019). Three endoleaks required treatment, and 1 fatal rupture of the thoracic aneurysm treated occurred 6 months after the initial repair. Migrations were detected in 4 patients. The maximal aneurysm size decreased yearly by 9.15% ( P = .01) or by 13.5% ( P = .0005) if patients with endoleaks (n = 3 patients) were excluded. Both the proximal and distal neck dilated slightly over the course of follow-up ( P = .019 and P = .001, respectively). The length of the proximal neck was a significant predictor of the risk for endoleakage ( P = .02). Conclusion: The treatment of descending thoracic aortic aneurysms with an endovascular approach is feasible and may, in some patients, offer the best means of therapy. Early complications were primarily related to device design and patient selection. All aneurysms without endoleaks decreased in size after treatment. Late complications were associated with changing aneurysm morphologic features and device migration. The morphologic changes remain somewhat unpredictable; however, alterations in device design may result in improved fixation and more durable aneurysm exclusion. (J Vasc Surg 2000;31:147-56.)

Intraoperative US in interactive image-guided neurosurgery.

Tissue movement can be a significant source of error in image-guided neurosurgery. A surgical guidance system that incorporates preoperative image information (eg, magnetic resonance [MR] imaging data) and intraoperative ultrasound (US) allows detection of tissue deformation during neurosurgery. An interactive image overlay tool allows a region of interest (ROl) to be defined and permits the operator to move the ROI over the MR or US image and overlay the associated image (US or MR) within the ROl. The system can be validated with a deformable multimodality phantom. Before deformation of the phantom, good agreement between the MR imaging and US data overlay confirms proper registration of the MR and US images; after deformation, the overlay demonstrates significant distortion of ventricles and movement of simulated blood vessels. Intraoperatively, this information helps establish the orientation of the US image being displayed by providing an oblique MR image that coincides with the live US view. The superior anatomic display of MR imaging also helps the surgeon interpret the corresponding US images. Finally, the system enables the surgeon to evaluate the patient-MR image registration by comparing structures on the MR images and live US images and using the overlay tool to visualize discrepancies.