Transcavernous Resection of an Upper Clival Chondrosarcoma: “Cavernous Sinus as a Route”: 2-Dimensional Operative Video

Complete resection of skull base chondrosarcomas offers the potential for a durable, or even lifelong, cure and is best achieved at the first surgery.1,2 When a skull base chondrosarcoma is located at the upper clivus and in the interpeduncular cistern and invading laterally toward the petrous apex and cavernous sinus, the traditional approaches, ie, endonasal endoscopic or middle fossa approaches, are not adequate for the exposure and resection. The transcavernous sinus approach has been utilized to remove tumor from the cavernous sinus and as a corridor to the interpeduncular cistern and upper clivus, originally described for the clipping of basilar apex aneurysms. We present a case of a chondrosarcoma centered in the upper clivus and eroding the right posterior clinoid, analogous to the location of a giant basilar apex aneurysm. Detailed study of the tumor extension, bony invasion, and relationship with neuroanatomy dictated the most effective surgical approach.3,4 Neuronavigation and intraoperative magnetic resonance imaging (MRI) facilitated the gross total resection of the tumor in the Advanced Multimodality Image-Guided Operating (AMIGO) suite. Achieving a gross total tumor removal of this World Health Organization (WHO) grade I chondrosarcoma, adjuvant irradiation can be withheld1 and the patient monitored with serial imaging. The patient did well after the surgery. The patient consented for surgery and the use of photography.

Recurrent Chordoma Resection in the Advanced Multimodality Image Guided Operating Suite: 2-Dimensional Operative Video

Recurrent skull base chordomas are challenging lesions. They already had maximum radiation, and in the absence of any effective medical treatment, surgical resection is the only treatment.1,2 Surgery on recurrent previously radiated chordomas, however, carries much higher risk and the likelihood of subtotal resection. Maximizing tumor resection allows longer tumor control.3-5 The Advanced Multimodality Image Guided Operating Suite developed at the Brigham and Women's Hospital, Harvard Medical School, with the support of the National Institutes of Health, provides an optimal environment to manage these tumors. It offers the capability to obtain and integrate multiple modalities during surgery, including magnetic resonance imaging (MRI), positron emission tomography-computed tomography (PET-CT), endoscopy, ultrasound, fluoroscopy, and the ability to perform emergent endovascular procedures.5-7 The patient is a 39-yr-old male, presenting after 19 yr follow-up of a surgical resection and proton beam treatment for a skull base chordoma. He developed progressive ophthalmoplegia due to recurrence of his chordoma at the right petrous apex and cavernous sinus. Preoperative angiography demonstrated narrowing of the petrous segment of the right carotid artery suspect of radiation-induced angiopathy. The presence of radiation-induced angiopathy increases the risk of intraoperative carotid rupture, and the availability of endovascular intervention in the operative suite added favorable preparedness to deal with such complications if they happen. Given the clinical and radiological progression, surgical intervention was carried out through the prior zygomatic approach with the goal of performing maximum resection.8 The patient had an uneventful postoperative course and remained stable until he had a second recurrence 4 yr later. The patient consented to the procedure.

Validation of Automated Biventricular Myocardial Segmentation from Coronary Computed Tomographic Angiography for Multimodality Image Fusion

PurposeImage fusion strategies of myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA) have shown increased diagnostic power. However, their clinical feasibility is hindered by the lack of efficient algorithms for the extraction of cardiac anatomy from CCTA datasets. The aim of this work was to validate our previously published algorithm for automated cardiac segmentation of CCTAs in a larger cohort of subjects while testing its application in clinical settings.MethodsThree borders were automatically and manually extracted on sixty-three clinical CCTAs: left and right endocardia (LV, RV) and the biventricular epicardium (EPI). Impact of image resolutions and inter-operator variability on accuracy and robustness of automated processing were evaluated. Automated algorithm accuracy was assessed with the Dice Similarity Coefficient (DSC) and the surface-to-surface distance metric. Relevant quantities were compared for automated versus manual segmentations: LV and RV volumes, myocardial mass and LV myocardial mass.ResultsLower resolution images offered an acceptable trade-off for accuracy and processing time (45 sec). DSC for LV, RV, EPI borders were 0.88, 0.80 and 0.89. Automated versus manual correlation coefficients for LV and RV vol, myo and LV mass were 0.96, 0.73, 0.84 and 0.67 with inter-operator agreement > 0.93 for three variables. Consistent and improved results were evidenced at higher resolutions.ConclusionOur algorithms allowed efficient automated cardiac segmentation from CT imagery with minimal user intervention, clinically acceptable times and accuracy. The reported results show promise for its use in a clinical environment, specifically in the context of image fusion.

Comparison of radiographer interobserver image registration variability using cone beam CT and MR for cervix radiotherapy

Objectives: The aim of this study was to assess the consistency of therapy radiographers performing image registration using cone beam computed tomography (CBCT)-CT, magnetic resonance (MR)-CT, and MR-MR image guidance for cervix cancer radiotherapy and to assess that MR-based image guidance is not inferior to CBCT standard practice. Methods: 10 patients receiving cervix radiation therapy underwent daily CBCT guidance and magnetic resonance (MR) imaging weekly during treatment. Offline registration of each MR image, and corresponding CBCT, to planning CT was performed by five radiographers. MR images were also registered to the earliest MR interobserver variation was assessed using modified Bland–Altman analysis with clinically acceptable 95% limits of agreement (LoA) defined as ±5.0 mm. Results: 30 CBCT-CT, 30 MR-CT and 20 MR–MR registrations were performed by each observer. Registration variations between CBCT-CT and MR-CT were minor and both strategies resulted in 95% LoA over the clinical threshold in the anteroposterior direction (CBCT-CT ±5.8 mm, MR-CT ±5.4 mm). MR–MR registrations achieved a significantly improved 95% LoA in the anteroposterior direction (±4.3 mm). All strategies demonstrated similar results in lateral and longitudinal directions. Conclusion: The magnitude of interobserver variations between CBCT-CT and MR-CT were similar, confirming that MR-CT radiotherapy workflows are comparable to CBCT-CT image-guided radiotherapy. Our results suggest MR–MR radiotherapy workflows may be a superior registration strategy. Advances in knowledge: This is the first publication quantifying interobserver registration of multimodality image registration strategies for cervix radical radiotherapy patients.