Advances in imaging of the paranasal sinuses

Optimization of paranasal sinus CT procedure: Ultra-low dose CT as a roadmap for pre-functional endoscopic sinus surgery

OBJECTIVE

To assess image quality and radiation dose associated with ultra-low dose CT protocol for patients with benign paranasal sinus diseases undergoing functional endoscopic surgery (FESS).

METHODS

We scanned the head portion of Alderson RANDO phantom on a second generation, dual-source, multidetector-row CT scanner (Siemens Definition Flash) using standard-dose and five low-dose protocols. Two radiologists assessed the image quality for each protocol to determine best ultra-low-dose protocols for imaging patients with benign paranasal sinus diseases undergoing FESS. The ultra-low-dose CT protocols were then used for scanning. Thereafter, 40 adult patients (age range 18-54 years, M:F 23:17) were scanned with the four low dose scanning protocols (10 patients per protocol). On both transverse and coronal reformatted CT images, two radiologists assessed visibility of key anatomic landmarks for FESS on a 2-point scale (1 = clear and complete visualization; 2 = suboptimal visualization). Data were analyzed with descriptive statistics and Cohen's kappa coefficient for interobserver agreement.

RESULTS

In phantom study, the lowest dose scan protocol (CTDI_vol 2.1 mGy, 70 kV, 75 mAs) was unacceptable due to poor image quality. For patient studies, both radiologists gave acceptable image quality scores for ultra-low-dose scan protocol with axial scan mode, automatic tube potential selection and tube current modulation (CTDI_vol 2.2 mGy; DLP 22.9 mGy.cm) with up to 60% lower dose compared to prior standard-dose CT (CTDI_vol 5.3 mGy; DLP 73.5 mGy.cm).

CONCLUSIONS

Ultra-low-dose CT protocol provides sufficient image quality for scanning patients undergoing functional endoscopic surgery for benign paranasal sinus diseases.

Imaging Sinonasal disease with MRI: Providing insight over and above CT

This article illustrates and discusses the applications and value of magnetic resonance imaging (MRI) in the evaluation of sinonasal disease. There are several clinical scenarios where MRI can add value over conventional computed tomography (CT) evaluation of the sinonasal spaces. Specifically, MRI can provide insight through better depiction of the anatomy of certain sinonasal sub-sites including the olfactory structures. It can aid in evaluating anosmia, sinusitis (fungal sinusitis and complications), benign and malignant lesions, CSF leaks and pathology extending into sinonasal spaces.

PET/MR Imaging in Head and Neck Cancer: Current Applications and Future Directions

Clinical PET/MR imaging is being implemented at institutions worldwide as part of the standard-of-care imaging for select oncology patients. This article focuses on oncologic applications of PET/MR imaging in cancers of the head and neck. Although current published literature is relatively sparse, the potential benefits of a hybrid modality of PET/MR imaging are discussed along with several possible areas of research. With the increasing number of PET/MR imaging scanners in clinical use and ongoing research, the role of PET/MR imaging in the management of head and neck cancer is likely to become more evident in the near future.

Current Trends in Sinonasal Imaging

As endoscopic sinus surgery (ESS) has evolved since its introduction to the United States, so has technology for imaging the sinonasal cavities. Although imaging is most frequently performed for evaluating chronic sinusitis refractory to medical therapy, its uses have expanded beyond inflammatory sinus disease. Multidetector Computed Tomography is the current workhorse for both diagnosis and preoperative planning in prospective ESS patients, while MR imaging remains a complementary tool for evaluating suspected tumors or intracranial and orbital complications of rhinosinusitis. In this article, the authors review current trends and potential future directions in the use of these modalities for sinus imaging.

Imaging Characteristics of Olfactory Neuroblastoma (Esthesioneuroblastoma)

This presentation outlines the clinical and imaging characteristics of esthesioneuroblastoma.

Clinical application of virtual endoscopy as a support system for endoscopic sinus surgery

CONCLUSIONS

Computer processing of conventional CT images can provide virtual endoscopic images (VEIs). Surgeons observing these images feel as if they are observing the lesion using an endoscope. Simulation based on animated VEIs before endoscopic sinus surgery (ESS) is useful for the improvement of surgical safety and surgeons' education. Although the production of VEIs requires certain surgical experience, after the production of VEIs, surgeons can repeat simulation of a surgical procedure and have confidence in the actual operation.

OBJECTIVE

We investigated the clinical application of CT-reconstructed VEIs as a support system for ESS.

MATERIALS AND METHODS

A GE Light Speed Ultra 16 as a 16-slice CT scanner and Advantage Workstation 4.2 were used. Software called Navigator in this workstation allows the production of CT-reconstructed VEIs. We applied simulation based on VEIs to endoscopic operations for mucocele or sinusitis.

RESULTS

In nine cases of mucoceles and sinusitis, simulation based on animated VEIs was applied. According to the simulation, surgeries were performed, and the mucoceles and obstructed sinuses could be opened readily and safely. This system was more effective when there were landmarks such as polyps or irregular mucosal surfaces allowing macroscopic confirmation ahead of the viewpoint.

CT versus MR: still a tough decision

CT and MRI are the two most widely used imaging modalities for evaluating head and neck pathology. There is continued controversy in the literature about which modality is superior for imaging different areas of the head and neck. This article summarizes the literature supporting the use of CT, MRI, or both for specific clinical scenarios in otolaryngology. Familiarity with the benefits and potential pitfalls of each modality allows referring physicians and radiologists to tailor imaging regimens to the needs of individual patients.