Near-infrared imaging of the sinuses: preliminary evaluation of a new technology for diagnosing maxillary sinusitis

A Comparison of Near-Infrared Imaging and Computerized Tomography Scan for Detecting Maxillary Sinusitis

OBJECTIVE

To investigate the use of near-infrared (NIR) imaging as a tool for outpatient clinicians to quickly and accurately assess for maxillary sinusitis and to characterize its accuracy compared to computerized tomography (CT) scan.

METHODS

In a prospective investigational study, NIR and CT images from 65 patients who presented to a tertiary care rhinology clinic were compared to determine the sensitivity and specificity of NIR as an imaging modality.

RESULTS

The sensitivity and specificity of NIR imaging in distinguishing normal versus maxillary sinus disease was found to be 90% and 84%, normal versus mild maxillary sinus disease to be 76% and 91%, and mild versus severe maxillary sinus disease to be 96% and 81%, respectively. The average pixel intensity was also calculated and compared to the modified Lund-Mackay scores from CT scans to assess the ability of NIR imaging to stratify the severity of maxillary sinus disease. Average pixel intensity over a region of interest was significantly different (P < .001) between normal, mild, and severe disease, as well as when comparing normal versus mild (P < .001, 95% CI 42.22-105.39), normal versus severe (P < .001, 95% CI 119.43-174.14), and mild versus severe (P < .001, 95% CI 41.39-104.56) maxillary sinus disease.

CONCLUSION

Based on this data, NIR shows promise as a tool for identifying patients with potential maxillary sinus disease as well as providing information on severity of disease that may guide administration of appropriate treatments.

Near-infrared Transillumination and Photodynamic Therapy Using Hypericin in Animal Laryngeal Tumors

BACKGROUND

We aimed to validate a pilot study of photodiagnosis using near infrared (NIR) transillumination and assess the clinical efficacy of hypericin-mediated photodynamic therapy (HYP-PDT) in a rabbit laryngeal cancer model in order to develop a novel therapeutic modality with complete remission and preservation of the functional organ.

METHODS

(1) In vitro study: VX tumor cells were subcultured and subjected to HYP-PDT. (2) In vivo study: A laryngeal cancer model was developed in which 12 rabbits were inoculated with a VX tumor suspension in the submucosal area of the left vocal fold using a transoral approach. All rabbits underwent NIR transillumination using light with a wavelength of 780 nm. The survival periods of the three treatment groups (6 rabbits in Group A: HYP-PDT, 3 each in Groups B and C: laser irradiation or HYP administration only) were analyzed.

RESULTS

The higher the HYP concentration, the lower the VX cell viability in response to HYP-PDT using 590 nm LED. Following HYP-PDT, small tumors in Group A-1 rabbits healed completely and the animals demonstrated a long survival period, and larger tumors in Group A-2 healed partially with a survival period that extended over 3 weeks after inoculation. The survival of Groups B and C were not different over the first 3 weeks of the study, and were shorter than in Group A.

CONCLUSION

We found HYP-PDT could be a curative therapy for early-stage cancers that may also preserve organ function, and may inhibit tumor progression and metastasis during advanced stages of laryngeal cancer.

Digital diaphanoscopy of the maxillary sinuses: A revival of optical diagnosis for rhinosinusitis

PURPOSE

The non-invasive diagnosis of acute rhinosinusitis (ARS) remains an unresolved problem of modern otolaryngology. Analog diaphanoscopy of reduced transillumination (shading) could be enhanced by a digital image processing of the maxillary sinuses. By this means, the limited ergonomics of this safe and low-cost method can be overcome, and merits renewed the investigation. Here, we compared the diagnostic sensitivity and specificity of digital diaphanoscopy and computed tomography (CT) in detecting shading in the maxillary sinus.

MATERIALS AND METHODS

We examined 103 adults using both digital diaphanoscopy of the maxillary sinus and native-phase cranial CT. We developed a scoring system for investigation of shading in the maxillary sinus using diaphanoscopy and compared the sensitivity and specificity with that of CT. Also, we documented a follow-up of acute rhinosinusitis.

RESULTS

In diagnosing shading in the maxillary sinus, digital diaphanoscopy had a sensitivity of 86% and a specificity of 88%. Digital diaphanoscopy can be used not only in the screening of ARS but also for documentation of its course.

CONCLUSION

This study supports the role of modern digital diaphanoscopy in the diagnosis of shading in the maxillary sinus, especially in patients with ARS when CT imaging is not recommended. The ergonomics of analog diaphanoscopy could be significantly improved for physicians and patients by the implementation of modern hardware and software components. Further development of the technique and the use of several discrete wavelengths will improve this method's sensitivity and specificity.

Monte Carlo modeling of light propagation in the human head for applications in sinus imaging

Sinus blockages are a common reason for physician visits, affecting one out of seven people in the United States, and often require medical treatment. Diagnosis in the primary care setting is challenging because symptom criteria (via detailed clinical history) plus objective imaging [computed tomography (CT) or endoscopy] are recommended. Unfortunately, neither option is routinely available in primary care. We previously demonstrated that low-cost near-infrared (NIR) transillumination correlates with the bulk findings of sinus opacity measured by CT. We have upgraded the technology, but questions of source optimization, anatomical influence, and detection limits remain. In order to begin addressing these questions, we have modeled NIR light propagation inside a three-dimensional adult human head constructed via CT images using a mesh-based Monte Carlo algorithm (MMCLAB). In this application, the sinus itself, which when healthy is a void region (e.g., nonscattering), is the region of interest. We characterize the changes in detected intensity due to clear (i.e., healthy) versus blocked sinuses and the effect of illumination patterns. We ran simulations for two clinical cases and compared simulations with measurements. The simulations presented herein serve as a proof of concept that this approach could be used to understand contrast mechanisms and limitations of NIR sinus imaging.

In vivo deep brain imaging of rats using oral-cavity illuminated photoacoustic computed tomography

Using internal illumination with an optical fiber in the oral cavity, we demonstrate, for the first time, photoacoustic computed tomography (PACT) of the deep brain of rats in vivo. The experiment was performed on a full-ring-array PACT system, with the capability of providing high-speed cross-sectional imaging of the brain. Compared with external illumination through the cranial skull, internal illumination delivers more light to the base of the brain. Consequently, in vivo photoacoustic images clearly reveal deep brain structures such as the hypothalamus, brain stem, and cerebral medulla.

Extratympanic observation of middle ear structure using a refractive index matching material (glycerol) and an infrared camera

High-resolution computed tomography has been used mainly in the diagnosis of middle ear disease, such as high-jugular bulb, congenital cholesteatoma, and ossicular disruption. However, certain diagnoses are confirmed through exploratory tympanotomy. There are few noninvasive methods available to observe the middle ear. The purpose of this study was to investigate the effect of glycerol as a refractive index matching material and an infrared (IR) camera system for extratympanic observation. 30% glycerol was used as a refractive index matching material in five fresh cadavers. Each material was divided into four subgroups; GN (glycerol no) group, GO (glycerol out) group, GI (glycerol in) group, and GB (glycerol both) group. A printed letter and middle ear structures on the inside tympanic membrane were observed using a visible and IR ray camera system. In the GB group, there were marked a transilluminated letter or an ossicle on the inside tympanic membrane. In particular, a footplate of stapes was even transilluminated using the IR camera system in the GB group. This method can be useful in the diagnosis of diseases of the middle ear if it is clinically applied through further studies.

Rhinosinusitis in children

Rhinosinusitis is the inflammation of the mucous membranes of nose and paranasal sinus(es). 5-13% of upper respiratory tract infections in children complicate into acute rhinosinusitis. Though not life threatening, it profoundly affects child's school performance and sleep pattern. If untreated, it could progress to chronic rhinosinusitis (CRS). The pathogens involved in perpetuation of CRS consist of multidrug-resistant mixed microflora. CRS is challenging to manage and could further extend to cause eye or intracranial complications. In children, CRS diagnosis is often either missed or incomprehensive. Due to this, morbidity and strain on healthcare budget are tremendous. Flexible fiberoptic endoscopy has revolutionized management of CRS. Its utility in children is being increasingly recognized. Optimal management entails specific appropriate antimicrobials as well as treatment of underlying causes. The aim is to normalize sinus anatomy and physiology and regain normal mucociliary function and clearance.