Imaging of Skull Base and Orbital Invasion in Sinonasal Cancer: Correlation with Histopathology

The medial transorbital approach in cranioendoscopic skull base tumor resections for locally advanced tumors

BACKGROUND

Orbital structure preservation and avoidance of facial incisions without compromising oncological outcome are key to maintaining function and quality of life in locally advanced sinonasal tumor surgery. A transorbital approach at our institution has proven invaluable during cranioendoscopic skull base tumor resections and there are few descriptions of this in the literature.

METHODS

An IRB-approved retrospective chart review was conducted at a tertiary cancer center for patients between 2020 and 2022 undergoing cranioendoscopic tumor resections utilizing a transorbital approach. Data collected included histopathology, sinus origin, disease extent, stage, operative details, length of stay, neo-adjuvant treatment and adjuvant treatment. Recurrence, survival, and complication rates were assessed.

RESULTS

Four patients were identified for inclusion, including a SMARCB1-deficient carcinoma, esthesioneuroblastoma, squamous cell carcinoma and meningioma. All patients had resection of gross and microscopic disease with preservation of orbital contents. Post-operatively, one patient had mild diplopia on inferior gaze, all other patients had normal vision. Median follow-up was 9.5 months. One patient had recurrence of disease intracranially.

CONCLUSIONS

The cranioendoscopic approach with a medial transorbital incision has multiple benefits. It avoids the need for a Weber-Ferguson incision with associated facial scar, allows for early intra-operative assessment for orbital invasion using tactile feedback and safe dissection of disease while protecting the globe and rectus muscles. This leads to preservation of eye function while ensuring an oncological resection. Other advantages include ligation of the anterior ethmoid artery and access for reconstruction of the medial orbital wall.

Sinonasal Cancer: Improving Classification, Stratification and Therapeutic Options

The nasal cavities and paranasal sinuses are the site of origin of a wide spectrum of histologically and clinically distinct disease entities [...]

Diagnostic performance of MRI for the assessment of extraocular muscle invasion in malignant sinonasal tumors

PURPOSE

Preoperative assessment of extraocular muscle invasion is essential for therapeutic strategies and prognostic evaluation. The aim of this study was to assess the diagnostic accuracy of MRI for evaluation of extraocular muscle (EM) invasion by malignant sinonasal tumors.

MATERIALS AND METHODS

Consecutively, 76 patients of sinonasal malignant tumors with orbital invasion were included in the present study. Preoperative MRI imaging features were analyzed by two radiologists independently. The diagnostic performances of MR imaging features for detecting EM involvement were evaluated by comparing imaging findings to histopathology data.

RESULTS

A total of 31 extraocular muscles were involved by sinonasal malignant tumors in 22 patients, including 10 medial rectus muscles (32.2%), 10 inferior rectus muscles (32.2%), 9 superior oblique muscles (29.1%), and 2 external rectus muscles (6.5%). The EM involved by sinonasal malignant tumors usually showed relatively high signal intensity on T2-weighted images, indistinguishable from the tumor, nodular enlargement and abnormal enhancement (p = 0.001, < 0.001, < 0.001 and < 0.001, respectively). Using a combination of EM abnormal enhancement and indistinguishable from the tumor in multivariate logistic regression analysis, sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for detecting orbital EM invasion by sinonasal tumors were 93.5, 85.2, 76.3, 96.3 and 88%, respectively.

CONCLUSION

MRI imaging features show high diagnostic performance for the diagnosis of extraocular muscle invasion by malignant sinonasal tumors.

Utility of the deep learning technique for the diagnosis of orbital invasion on CT in patients with a nasal or sinonasal tumor

Background

In nasal or sinonasal tumors, orbital invasion beyond periorbita by the tumor is one of the important criteria in the selection of the surgical procedure. We investigated the usefulness of the convolutional neural network (CNN)-based deep learning technique for the diagnosis of orbital invasion, using computed tomography (CT) images.

Methods

A total of 168 lesions with malignant nasal or sinonasal tumors were divided into a training dataset (n = 119) and a test dataset (n = 49). The final diagnosis (invasion-positive or -negative) was determined by experienced radiologists who carefully reviewed all of the CT images. In a CNN-based deep learning analysis, a slice of the square target region that included the orbital bone wall was extracted and fed into a deep-learning training session to create a diagnostic model using transfer learning with the Visual Geometry Group 16 (VGG16) model. The test dataset was subsequently tested in CNN-based diagnostic models and by two other radiologists who were not specialized in head and neck radiology. At approx. 2 months after the first reading session, two radiologists again reviewed all of the images in the test dataset, referring to the diagnoses provided by the trained CNN-based diagnostic model.

Results

The diagnostic accuracy was 0.92 by the CNN-based diagnostic models, whereas the diagnostic accuracies by the two radiologists at the first reading session were 0.49 and 0.45, respectively. In the second reading session by two radiologists (diagnosing with the assistance by the CNN-based diagnostic model), marked elevations of the diagnostic accuracy were observed (0.94 and 1.00, respectively).

Conclusion

The CNN-based deep learning technique can be a useful support tool in assessing the presence of orbital invasion on CT images, especially for non-specialized radiologists.

PET-CT in Clinical Adult Oncology-V. Head and Neck and Neuro Oncology

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT) has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate attenuation correction, so that radioactivity from deep or dense structures can be better visualized, but with head and neck malignancies it is critical to provide correlating detailed anatomic imaging. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging, and surveillance. This series of six review articles provides an overview of the value, applications, and imaging and interpretive strategies of PET-CT in the more common adult malignancies. The fifth report in this series provides a review of PET-CT imaging in head and neck and neuro oncology.

Abstract

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging, and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In addition, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of oncology patients. Hundreds of different types of tumors exist, both pediatric and adult. A discussion of the role of FDG PET for all of these is beyond the scope of this review. Rather, this series of articles focuses on the most common adult malignancies that may be encountered in clinical practice. It also focuses on FDA-approved and clinically available radiopharmaceuticals, rather than research tracers or those requiring a local cyclotron. The fifth review article in this series focuses on PET-CT imaging in head and neck tumors, as well as brain tumors. Common normal variants, key anatomic features, and benign mimics of these tumors are reviewed. The goal of this review article is to provide the imaging professional with guidance in the interpretation of PET-CT for the more common head and neck malignancies and neuro oncology, and to inform the referring providers so that they can have realistic expectations of the value and limitations of PET-CT for the specific type of tumor being addressed.