Orbital magnetic resonance imaging of giant cell arteritis with ocular manifestations: a systematic review and individual participant data meta-analysis.

OBJECTIVES: We conducted a systematic review and individual participant data meta-analysis of publications reporting the ophthalmologic presentation, clinical exam, and orbital MRI findings in patients with giant cell arteritis and ocular manifestations. METHODS: PubMed and Cochrane databases were searched up to January 16, 2022. Publications reporting patient-level data on patients with ophthalmologic symptoms, imaged with orbital MRI, and diagnosed with biopsy-proven giant cell arteritis were included. Demographics, clinical symptoms, exam, lab, imaging, and outcomes data were extracted. The methodological quality and completeness of reporting of case reports were assessed. RESULTS: Thirty-two studies were included comprising 51 patients (females = 24; median age, 76 years). Vision loss (78%) and headache (45%) were commonly reported visual and cranial symptoms. Ophthalmologic presentation was unilateral (41%) or bilateral (59%). Fundus examination most commonly showed disc edema (64%) and pallor (49%). Average visual acuity was very poor (2.28 logMAR ± 2.18). Diagnoses included anterior (61%) and posterior (16%) ischemic optic neuropathy, central retinal artery occlusion (8%), and orbital infarction syndrome (2%). On MRI, enhancement of the optic nerve sheath (53%), intraconal fat (25%), and optic nerve/chiasm (14%) was most prevalent. Among patients with monocular visual symptoms, 38% showed pathologic enhancement in the asymptomatic orbit. Six of seven cases reported imaging resolution after treatment on follow-up MRIs. CONCLUSIONS: Vision loss, pallid disc edema, and optic nerve sheath enhancement are the most common clinical, fundoscopic, and imaging findings reported in patients diagnosed with giant cell arteritis with ocular manifestations, respectively. MRI may detect subclinical inflammation and ischemia in the asymptomatic eye and may be an adjunct diagnostic tool. CLINICAL RELEVANCE STATEMENT: Brain and orbital MRIs may have diagnostic and prognostic roles in patients with suspected giant cell arteritis who present with ophthalmic symptoms.

Otopathologic and Computed Tomography Correlation of Internal Auditory Canal Diverticula in Otosclerosis.

INTRODUCTION: Internal auditory canal (IAC) diverticula, also known as IAC cavitary lesions or anterior cupping of the IAC, observed in otopathologic specimens and high-resolution computed tomography (CT) scans of the temporal bone are thought to be related to otosclerosis. Herein, we examined the usefulness of CT scans in identifying diverticula and determined whether IAC diverticula are associated with otosclerosis on otopathology. METHODS: One hundred five consecutive specimens were identified from the National Temporal Bone Hearing and Balance Pathology Resource Registry. Inclusion criteria included the availability of histologic slides and postmortem specimen CT scans. Exclusion criteria included cases with severe postmortem changes or lesions causing bony destruction of the IAC. RESULTS: Ninety-seven specimens met criteria for study. Of these, 42% of the specimens were from male patients, and the average age of death was 77 years (SD = 18 yr). IAC diverticula were found in 48 specimens, of which 46% were identified in the CT scans. The mean area of the IAC diverticula was 0.34 mm 2 . The sensitivity and specificity of detecting IAC diverticula based on CT were 77% and 63%, respectively. Overall, 27% of specimens had otosclerosis. Histologic IAC diverticula were more common in specimens with otosclerosis than those without (37.5% versus 16%; p = 0.019). Cases with otosclerosis had a greater mean histologic diverticula area compared with nonotosclerosis cases (0.69 mm 2 versus 0.14 mm 2 ; p = 0.001). CONCLUSION: IAC diverticula are commonly found in otopathologic specimens with varied etiologies, but larger diverticula are more likely to be associated with otosclerosis. The sensitivity and specificity of CT scans to detect IAC diverticula are limited.

Computed Tomography Density as a Bio-marker for Histologic Grade of Otosclerosis: A Human Temporal Bone Pathology Study.

HYPOTHESIS: Computed tomography (CT) density measurement can be used to objectively distinguish otosclerosis from normal bone and to determine histologic grades of otosclerosis. BACKGROUND: Otosclerosis can be seen on CT as subtle radiolucent areas. An objective radiologic measurement that corresponds to known otosclerosis pathology may improve diagnostic accuracy, and could be used as a radiologic biomarker for otosclerosis grade. METHODS: A blinded, randomized evaluation of both histologic grade on histopathology slides and CT density measurement was performed on 78 human temporal bone specimens (31 with otosclerosis and 47 controls) that had undergone high-resolution multi-detector CT before histologic processing. Assessments were performed at 11 regions of interest (ROIs) in the otic capsule for each specimen. RESULTS: The CT density measurement mean (Hounsfield Units) ± standard deviation for all ROIs (Nos. 1-9) was 2245 ± 854 for grade 0 (no otosclerosis, n = 711), 1896 ± 317 for grade 1 (inactive otosclerosis, n = 109), and 1632 ± 255 for grades 2 and 3 combined (mixed/active otosclerosis, n 35). There was a strong inverse correlation of CT density to histologic grade at ROIs Nos. 1-5 (ANOVA, p < 0.0001). The inter-rater reliability for CT density was very good (correlation coefficient 0.87, p < 0.05). ROC curves suggested a cut-off of 2,150HU to distinguish otosclerosis from normal bone, and 1,811HU to distinguish low grade from mixed/high grade otosclerosis. CONCLUSIONS: In human temporal bone specimens, CT density may be used to distinguish normal bone from bone involved by otosclerosis. A higher histologic grade (i.e., indicating a more active otosclerotic focus) correlated with lower density.

Molecular immuno-imaging improves tumor detection in head and neck cancer.

Detection and accurate delineation of tumor is important for the management of head and neck squamous cell carcinoma (HNSCC) but is challenging with current imaging techniques. In this study, we evaluated whether molecular immuno-imaging targeting myeloperoxidase (MPO) activity, an oxidative enzyme secreted by many myeloid innate immune cells, would be superior in detecting tumor extent compared to conventional contrast agent (DTPA-Gd) in a carcinogen-induced immunocompetent HNSCC murine model and corroborated in human surgical specimens. In C57BL/6 mice given 4-nitroquinoline-N-oxide (4-NQO), there was increased MPO activity in the head and neck region as detected by luminol bioluminescence compared to that of the control group. On magnetic resonance imaging, the mean enhancing volume detected by the MPO-targeting agent (MPO-Gd) was higher than that by the conventional agent DTPA-Gd. The tumor volume detected by MPO-Gd strongly correlated with tumor size on histology, and higher MPO-Gd signal corresponded to larger tumor size found by imaging and histology. On the contrary, the tumor volume detected by DTPA-Gd did not correlate as well with tumor size on histology. Importantly, MPO-Gd imaging detected areas not visualized with DTPA-Gd imaging that were confirmed histopathologically to represent early tumor. In human specimens, MPO was similarly associated with tumors, especially at the tumor margins. Thus, molecular immuno-imaging targeting MPO not only detects oxidative immune response in HNSCC, but can better detect and delineate tumor extent than nonselective imaging agents. Thus, our findings revealed that MPO imaging could improve tumor resection as well as be a useful imaging biomarker for tumor progression, and potentially improve clinical management of HNSCC once translated.

CT-based assessment of laryngeal fracture patterns and associated soft tissue abnormality.

OBJECTIVE: Acute traumatic injuries to the larynx, including fractures of the hyoid bone, cricoid, and thyroid cartilage, are uncommon injuries. The purpose of this study was to assess fracture and soft tissue patterns associated with laryngeal trauma. METHODS: This was a retrospective review of patients with laryngeal fractures who presented to two level I trauma centers and underwent CT imaging. Imaging findings, including fractures of the cartilaginous structures of the larynx and hyoid bone, and soft tissue abnormalities including focal hematoma, edema with non-focal hemorrhage, and additional penetrating injuries were recorded. Frequencies of fracture patterns were recorded. RESULTS: Thyroid cartilage fractures were most frequently observed occurring in 45/55 patients, followed by cricoid fractures in 13/55 patients. Hyoid fractures were encountered in 8/55 patients. Multi-site fractures were observed in 12/55 patients with thyroid-cricoid fractures occurring in 8/12 patients, followed by thyroid-hyoid fractures in 2/12 patients. Most multi-site fractures occurred in association with focal supraglottic hematomas (10/12), supraglottic edema and non-focal hemorrhage (11/12), and focal subglottic hematoma (5/12). All 13 cricoid fractures occurred with either focal supraglottic hematoma (7), focal subglottic hematoma (4), or edema with non-focal hemorrhage (13). CONCLUSIONS: Thyroid cartilage fractures were the most frequently encountered fracture, followed by cricoid cartilage fractures. Cricoid fractures always occurred with soft tissue abnormalities. Recognition of fracture patterns in the setting of laryngeal trauma and associated patterns of soft tissue injury is important for practicing radiologists for early diagnosis of these conditions and reduction of associated morbidity. KEY POINTS: • Acute fractures to the larynx may be isolated fractures or occur as multi-focal fractures. • Thyroid cartilage fractures are the most frequent fractures followed by cricoid cartilage fractures. • Cricoid cartilage fractures always occurred in association with soft tissue abnormalities.

Orbital Involvement by Biphenotypic Sinonasal Sarcoma With a Literature Review.

PURPOSE: To document a case of a biphenotypic sinonasal sarcoma that impinged on the orbit via a tumor-induced mucocele and review the previous literature devoted to this condition. METHODS: A clinicopathologic case report with detailed histopathologic, immunohistochemical, and radiological studies with tabulations of previously reported cases and immunohistochemical stains for ruling out mimicking lesions. RESULTS: A biphenotypic sinonasal sarcoma arose from the ethmoid sinus in a middle-aged man. The tumor induced a mucocele that bowed the medial orbital lamina papyracea into the orbit and caused diplopia and mild proptosis. The biopsy's dual positivity for S100 and smooth muscle actin together with positive paired box 3 immunohistochemical staining established the diagnosis of biphenotypic sinonasal sarcoma. CONCLUSION: Biphenotypic sinonasal sarcoma, which can involve the orbit in 25% of cases, is a rare head and neck malignancy that has only recently been described. Biphenotypic sinonasal sarcoma is a low-grade, locally aggressive, nonmetastasizing sarcoma displaying both neural and muscle differentiation. It is further characterized by rearrangements of the PAX3 gene with multiple fusion partners, most commonly MAML3 (Mastermind like transcriptional coactivator 3). It occurs predominantly in middle-aged women and exclusively in the sinonasal tract. However, it can spread throughout the central facial structures to invade the brain if not detected early. Ophthalmologists should be aware of this new entity to avoid delays in diagnosis and treatment. The previous literature devoted to this condition was reviewed and analyzed for clinical, radiological, histopathological, and immunohistochemical features. In circumstances where molecular testing is not available, paired box 3 immunohistochemical staining can be used as an alternative diagnostic marker. The current case is most unusual because the orbital findings were induced by a mucocele caused by the tumor that obstructed the sinus ostium. This produced diplopia without direct tumor invasion into the orbital fat.

The Cochlear Cleft: CT Correlation With Histopathology.

OBJECTIVE: To show the histologic correlate of the cochlear cleft, a small low density focus just anterior to the oval window seen on computed tomography (CT) in three temporal bone specimens. PATIENTS: Three temporal bone specimens donated to the National Temporal Bone Registry from patients aged 34 weeks gestation, 42 years, and 89 years with cochlear clefts seen on CT were studied. INTERVENTION: Review and comparison of postmortem high-resolution CT and temporal bone histopathology MAIN OUTCOME MEASURE:: Correlation of CT findings with temporal bone histopathology. RESULTS: The cochlear cleft visible on CT as a pericochlear lucency anterior to the oval window corresponds to fatty marrow in areas of incomplete endochondral ossification of the otic capsule. The cochlear cleft is distinct from the fissula ante fenestram and can be present in adults. CONCLUSION: In these three cases, the cochlear cleft represents an area of fatty marrow from incomplete ossification of the otic capsule and can be present in adults. Care should be taken when interpreting temporal bone CT to avoid mistaking the cochlear cleft for true pathology (otosclerosis) of the temporal bone.

Nontraumatic Head and Neck Emergencies.

Head and neck imaging is an intimidating subject for many radiologists because of the complex anatomy and potentially serious consequences of delayed or improper diagnosis of the diverse abnormalities involving this region. The purpose of this article is to help radiologists to understand the intricate anatomy of the head and neck and to review the imaging appearances of a variety of nontraumatic head and neck conditions that bring patients to the emergency department, including acute infectious and inflammatory diseases and acute complications of head and neck neoplasms. These conditions are presented in five sections on the basis of their primary location of involvement: the oral cavity and pharynx, neck, sinonasal tract, orbits, and ears. Important anatomic landmarks are reviewed briefly in each related section.Online supplemental material is available for this article.©RSNA, 2019.

Vestibular Aqueduct Morphology Correlates With Endolymphatic Sac Pathologies in Menière's Disease-A Correlative Histology and Computed Tomography Study.

HYPOTHESIS: The vestibular aqueduct (VA) in Menière's disease (MD) exhibits different angular trajectories depending on the presenting endolymphatic sac (ES) pathology, i.e., 1) ES hypoplasia or 2) ES degeneration. BACKGROUND: Hypoplasia or degeneration of the ES was consistently found in inner ears affected by MD. The two etiologically distinct ES pathologies presumably represent two disease "endotypes," which may be associated with different clinical traits ("phenotypes") of MD. Recognizing these endotypes in the clinical setting requires a diagnostic tool. METHODS: 1) Defining the angular trajectory of the VA (ATVA) in the axial plane. 2) Measuring age-dependent normative data for the ATVA in postmortem temporal bone histology material from normal adults and fetuses. 3) Validating ATVA measurements from normative CT imaging data. 4) Correlating the ATVA with different ES pathologies in histological materials and CT imaging data from MD patients. RESULTS: 1) The ATVA differed significantly between normal adults and MD cases with ES degeneration, as well as between fetuses and MD cases with ES hypoplasia; 2) a strong correlation between ATVA measurements in histological sections and CT imaging data was found; 3) a correlation between the ATVA, in particular its axial trajectory in the opercular region (angle αexit), with degenerative (αexit < 120°) and hypoplastic ES pathology (αexit > 140°) was demonstrated. CONCLUSION: We established the ATVA as a radiographic surrogate marker for ES pathologies. CT-imaging-based determination of the ATVA enables endotyping of MD patients according to ES pathology. Future studies will apply this method to investigate whether ES endotypes distinguish clinically meaningful subgroups of MD patients.

Individualization of Clinical Target Volume Delineation Based on Stepwise Spread of Nasopharyngeal Carcinoma: Outcome of More Than a Decade of Clinical Experience.

PURPOSE: Radiation-related toxicity in nasopharyngeal carcinoma (NPC) is common. There are no well-established guidelines for clinical target volume (CTV) delineation with long-term follow-up. Current consensus continues to rely heavily on bony landmarks and fixed margins around the gross tumor volume (GTV), an approach used to define fields in the conventional 2- and 3-dimensional radiation therapy era. METHODS AND MATERIALS: We retrospectively evaluated patients with newly diagnosed nonmetastatic NPC treated with definitive radiation therapy using a technique of CTV delineation based on individual tumor extent and the orderly stepwise pattern of tumor spread. Dosimetric comparisons were made between national protocol HN001 and our contouring strategies on a representative early- and advanced-stage NPC. The primary endpoints were patterns of failure and local control; secondary endpoints included regional control and survival, estimated using the Kaplan-Meier method. RESULTS: Between 1999 and 2013, 73 patients (88% with stage 3-4 disease) were treated with median follow-up of 90 months for surviving patients. Median dose to GTV was 70 Gy. Four patients developed local recurrence and 1 patient developed regional recurrence. All locoregional recurrences occurred within the high-dose GTV. The 5-year local control, regional control, and overall survival was 94% (95% confidence interval [CI], 85%-98%), 99% (95% CI, 90%-100%), and 84% (95% CI, 73%-91%), respectively. Compared with HN001, our contouring strategy resulted in 62% and 36% reduction in CTV for T1 and T4 disease, respectively. In the T1 tumor, the reduction of doses to the contralateral parotid, optic nerve, and cochlea were 54%, 50%, 34% respectively. In the T4 case, there was a decrease of optic chiasm dose of 46% and contralateral optic nerve of 37%. There were 10 grade 3 toxicities. There was no grade 2 or higher xerostomia and no grade 4/5 toxicity. CONCLUSIONS: Our long-term experience with individualized CTV delineation based on stepwise patterns of spread results in excellent local control, with no recurrence outside the GTV.

Arterial Anomalies of the Middle Ear: A Pictorial Review with Clinical-Embryologic and Imaging Correlation.

The differential diagnosis of a red and/or pulsatile retrotympanic mass includes aberrant internal carotid artery, persistent stapedial artery (PSA), glomus tympanicum, and dehiscent jugular bulb. By recognizing the features of aberrant internal carotid artery and PSA on high-resolution computed tomography, these entities can be assessed by the radiologist. PSA is further classified by type because each type demonstrates a unique set of imaging features in addition to features common to all types. Although rarely encountered, it is important to reliably and consistently detect these anomalies because failure to do so can lead to disastrous surgical outcomes.

Clinicopathologic and Magnetic Resonance Imaging Analysis of a Multifocal Orbital Lymphoid Tumor.

OBJECTIVE: To distinguish between a multifocal orbital lymphoid tumor and a major simulator represented by a diffuse lymphaticovenous malformation. METHODS: We performed a comparison of clinical and radiographic (magnetic resonance imaging [MRI]) findings of these two disparate entities and demonstrated how a misdiagnosis can be prevented. RESULTS: Orbital lymphoid tumors develop in adults at around 60 years of age, whereas extensive lymphaticovenous malformations are generally detected in the first decade. Despite these differences, this is the first description of clinical confusion between them. MRI with gadolinium injection in the current lymphoid tumor displayed a low signal on T2-weighted images, rapid and uniform enhancement, and reduced diffusion. Lymphaticovenous malformations are heterogeneous, display poor or only focal perfusion, and fail to exhibit diminished diffusion. Newer techniques such as diffusion-weighted imaging and dynamic contrast-enhanced imaging may be able to provide additional differential diagnostic information. The final pathologic diagnosis was an extranodal marginal zone lymphoma. CONCLUSIONS: Despite the obvious distinctions between orbital lymphoid tumors and lymphaticovenous malformations, several clinical radiologic specialists misdiagnosed the present orbital lesion as a vascular lesion. A combined clinicoradiographic analysis should obviate such errors and facilitate the correct diagnosis in the future.

Atypical MRI and Histopathological Findings in Dermoid Cyst.

On images, a dermoid cyst is often described as resembling a "sack of marbles" or "marbles in a bag". Typically, it comprises an inhomogeneity filled with multiple nodules in a fluid matrix on both computed tomography and magnetic resonance imaging (MRI). How it appears, however, will vary depending on its histological contents, which may cause confusion in arriving at a diagnosis. This report describes a dermoid cyst in the floor of the mouth of a 55 year-old woman that showed an atypical internal appearance on MRI. Most of the lesion showed homogeneous high signal intensity on T1 - and T2-weighted images, suggesting that it was derived from fat. A small area within the mass, however, showed moderate signal intensity almost equal to that of muscle on T1-weighted images and high signal intensity on fat-suppressed T2-weighted images. Given the location of the lesion, a dermoid cyst was one possible diagnosis. A lipoma or lipoma variants were also considered, however, based on signal intensity. Histopathological section of the excised specimen revealed a dermoid cyst with sebaceous glands in its walls and keratin in its cavity. Dermoid cysts show variation in their internal structures and contents. Since MRI can reflect such histological variation, signal intensity requires careful interpretation.

Noncontrast vestibular schwannoma surveillance imaging including an MR cisternographic sequence: is there a need for postcontrast imaging?

OBJECTIVE: The purpose of this study was to evaluate the use of a noncontrast MRI protocol that includes a cisternographic sequence (CISS/FIESTA/3D DRIVE) compared to a protocol that includes a gadolinium-enhanced sequence in order to determine whether a noncontrast approach could be utilized to follow vestibular schwannomas. METHODS: A total of 251 patients with vestibular schwannomas who underwent MRI of the temporal bones that included both cisternographic sequence and postcontrast T1 imaging between January 2000 and January 2016 for surveillance were included in this retrospective study. The size of the vestibular schwannomas was independently assessed on a noncontrast MR cisternographic sequence and compared to size measurements on a postcontrast sequence. The evaluation of intralesional cystic components (identified as T2 signal hyperintensity) and hemorrhagic components (identified with intrinsic T1 hyperintensity) on noncontrast MR sequences was compared to evaluation on postcontrast MR sequences to determine whether additional information could be derived from the postcontrast sequences. Additionally, any potentially clinically significant, incidentally detected findings on the postcontrast T1 sequences were documented and compared with the detection of these findings on the precontrast images. RESULTS: No significant difference in vestibular schwannoma size was found when comparing measurements made on the images obtained with the MR cisternographic sequence and those made on images obtained with the postcontrast sequence (p = 0.99). Noncontrast MR images were better (detection rate of 87%) than postcontrast images for detection of cystic components. Noncontrast MR images were also better for identifying hemorrhagic components. No additional clinically relevant information regarding the tumors was identified on the postcontrast sequences. CONCLUSIONS: Based on the results of this study, a noncontrast MR protocol that includes a cisternographic sequence would be sufficient for the accurate characterization of size and signal characteristics of vestibular schwannomas, obviating the need for gadolinium contrast administration for the routine surveillance of these lesions.

Toward Optimizing Cervical Vestibular Evoked Myogenic Potentials (cVEMP): Combining Air-Bone Gap and cVEMP Thresholds to Improve Diagnosis of Superior Canal Dehiscence.

OBJECTIVE: To develop a novel approach combining low-frequency air-bone gap (ABG) and cervical vestibular evoked myogenic potential (cVEMP) thresholds to improve screening for superior canal dehiscence (SCD) syndrome. STUDY DESIGN: Retrospective study. SETTING: Tertiary care center. PATIENTS: One hundred forty patients with SCD and 21 healthy age-matched controls were included. Ears for each patient were divided into three groups based on computed tomography (CT) findings: 1) dehiscent, 2) thin, or 3) unaffected. MAIN OUTCOME MEASURES: cVEMP and audiometric thresholds were analyzed and differences among groups were evaluated. RESULTS: We define the third window indicator (TWI) as the cVEMP thresholds at 500, 750, and 1000 Hz adjusted for the ABG at 250 Hz (i.e., subtracting ABG from cVEMP threshold). The TWI differentiates between dehiscent and nondehiscent control ears with a sensitivity of 82% and specificity of 100%, corresponding to a positive predictive value of 100%. ABGs and cVEMP thresholds were similar for healthy controls and patients with thin bone over the superior canal. CONCLUSION: This is the largest study to date examining the usefulness of cVEMPs in the diagnosis of SCD. Our "third window indicator" (TWI) combines cVEMP thresholds with the ABG at 250 Hz to improve the ability to screen patients with SCD symptoms.

Precurved Cochlear Implants and Tip Foldover: A Cadaveric Imaging Study.

Objective This study aims to define a reliable protocol for radiographic identification of placement and tip foldover of newly designed precurved and straight electrodes. Study Design Prospective imaging study. Setting Academic institution. Methods Three models of cochlear implants (Cochlear, MED-EL, and Advanced Bionics) were inserted into fresh cadaveric specimens (n = 2) in 3 configurations (normal positioning in the scala tympani, intracochlear tip foldover, and placement into the vestibular system) for a total of 9 implant scenarios. Specimens were imaged with plain radiography in Stenvers projection, as well as by high-resolution computed tomography. Results Electrode placement and presence or absence of electrode tip foldover were easily identified in all 9 scenarios on plain radiography based on the described technique. Each was confirmed with high-resolution computed tomography. Plain film temporal bone images of new electrode designs with proper and improper placement are provided for reference. Conclusion A defined protocol for intraoperative plain film radiography allowed for reliable imaging of 3 newly designed cochlear implant electrodes and immediate identification of extracochlear placement and tip foldover. Findings may be used for intraoperative confirmation of electrode array placement.

Chapter 2 Squamous Cell Carcinoma of the Head and Neck-Imaging Evaluation of Regional Lymph Nodes and Implications for Management.

The presence of cervical lymph node metastases is a major prognostic factor in squamous cell carcinoma of the head and neck. The presence of a solitary ipsilateral metastatic lymph node reduces expected survival by almost 50%, and the presence of regional metastatic nodes at the time of presentation is the strongest predictor of recurrence or the development of distant metastases or both. Therefore, accurate identification of metastatic cervical lymph nodes is essential for staging and treatment planning. Pretreatment imaging is important for identifying clinically occult pathologic nodes as well as delineating nodal size and morphologic characteristics used in staging. The role of imaging and its implications for management are reviewed, with emphasis on the traditional modalities and imaging criteria, including evaluation for extranodal extension.

Applications of Dual-Energy Computed Tomography for the Evaluation of Head and Neck Squamous Cell Carcinoma.

There are multiple emerging applications of dual-energy computed tomography (DECT) for the evaluation of pathology in the head and neck, in particular head and neck squamous cell carcinoma. Studies suggest that DECT image sets reconstructed as supplements to routine diagnostic images may improve lesion visualization, determination of tumor extent, and identification of invasion of critical anatomic structures. This article reviews the evidence for the use and potential advantages of supplementary DECT reconstructions for the evaluation of head and neck squamous cell carcinoma. A summary of potentially useful reconstructions and a suggested approach for multiparametric DECT evaluation of head and neck cancer based on current evidence are presented.

Low-Energy Virtual Monochromatic Dual-Energy Computed Tomography Images for the Evaluation of Head and Neck Squamous Cell Carcinoma: A Study of Tumor Visibility Compared With Single-Energy Computed Tomography and User Acceptance.

OBJECTIVE: Dual-energy computed tomography (CT) 40-keV virtual monochromatic images (VMIs) have been reported to improve visualization of head and neck squamous cell carcinoma, but a direct comparison to single-energy CT (SECT) is lacking, and there is debate regarding subjective user preference. We compared 40-keV VMIs with SECT and performed a subjective evaluation of their utility and acceptability for clinical use. METHODS: A total of 60 dual-energy CT and 60 SECT scans from 2 different institutions were evaluated. Tumor conspicuity was evaluated objectively using absolute and relative attenuation and subjectively by 3 head and neck specialists and 3 general radiologists. RESULTS: Tumors had significantly higher absolute and relative attenuation on 40-keV VMIs (P < 0.0001). Subjectively, the 40-keV VMIs improved visualization, with substantial (κ, 0.61-0.80) to almost perfect (κ, 0.81-1) interrater agreements. CONCLUSIONS: The 40-keV VMIs improve tumor visibility objectively and subjectively both by head and neck specialists and general radiologists.