Defining the Shape of the Mylohyoid Muscle: A Morphometric Imaging Study.

OBJECTIVES: Implantable hypoglossal nerve stimulation (HNS) therapy is an evolving therapeutic alternative for patients with refractory obstructive sleep apnea (OSA). The muscular anatomy of this region has implications for surgical access through this zone as well as positioning and anchoring of hardware in this area. The purpose of this study was to radiologically describe the topography of the mylohyoid muscle and adjacent structures across a wide age spectrum. METHODS: We retrospectively evaluated computed tomography scans of the neck in 102 patients who were imaged for reasons unrelated to the floor of mouth or submental space. Patients with prior surgery or pathology in the area of interest were excluded. Fourteen relevant muscle measurements were made on a midline sagittal image and a coronal image positioned at the midpoint between the hyoid bone and the mandible. RESULTS: We included 49 men and 53 women with an average age of 44 years (range 19-70). The average mylohyoid length was 42 mm; the average distance between the anterior digastric bellies was 17 mm. The average angle of the central mylohyoid was 174° in the sagittal plane and 164° in the coronal plane. Several measurements were significantly correlated with patient age, including the angle measurements and the distance between the digastric muscles. Aberrant digastric anatomy was common. CONCLUSIONS: The mylohyoid muscle has multiple radiologically distinct segments with predictable curvatures. An understanding of submental muscular anatomy, along with its variability between patients, may be beneficial to the development of bilateral implantable neurostimulation technology for the treatment of refractory OSA. LEVEL OF EVIDENCE: N/A Laryngoscope, 2024.

Imaging of Maxillofacial Injuries.

This article reviews the system of facial buttresses and discusses the role of diagnostic imaging in the evaluation of the patient with maxillofacial trauma.

Rate of metallic foreign bodies found on orbital radiographs prior to MRI.

OBJECTIVE: The purpose of this research is to more precisely quantify the positivity rate for conventional radiographs (CR) of the orbit performed for the purpose of pre-MR screening in patients at risk of having a radio-opaque orbital foreign body (ROFB). METHODS: By review of electronic medical records, we identified 47,237 patients who had undergone orbital CR for clearance of ROFB prior to MRI. The reports from these examinations were manually reviewed, and the examinations with positive findings were re-interpreted by a CAQ-certified head and neck radiologist. The rate of ROFB found in these examinations was reported and compared to historical estimates in the literature. RESULTS: 328 of the 47,237 examinations (0.69 %) were originally interpreted as positive for ROFB. Upon re-review, only 39 of the 47,237 examinations (0.083 %, 95 % CI 0.06 %-0.11 %) contained ROFB that were in locations that posed a risk to ocular or vascular structures or were in an equivocal location. Almost all of the patients with false-positive initial interpretations had been denied MRI. DISCUSSION: The rate of ROFB discovered on clearance CR of the orbits prior to MRI is far less than previously estimated in the radiology literature. More conservative guidelines for MR clearance may be useful to reduce costs, mitigate imaging delays, and avoid unnecessary denial of imaging.

The Sagittal Angle of the Trigeminal Nerve at the Porus Trigeminus is a Radiologic Predictor of Surgical Outcome in Microvascular Decompression for Classical Trigeminal Neuralgia.

BACKGROUND AND OBJECTIVES: Classical trigeminal neuralgia (cTN) is a painful disease. Microvascular decompression (MVD) provides immediate and durable relief in many patients. A variety of positive and negative prognostic biomarkers for MVD have been identified. The sagittal angle of the trigeminal nerve at the porus trigeminus (SATNaPT) is an MRI biomarker that can identify a subset of patients with cTN whose trigeminal nerve anatomy is different from normal controls. The purpose of this case-control study was to determine whether an abnormally hyperacute SATNaPT is a negative prognostic biomarker in patients with cTN undergoing MVD. METHODS: Preoperative MRIs from 300 patients with cTN who underwent MVD were analyzed to identify patients with a hyperacute SATNaPT (defined as less than 3 SDs below the mean). The rate of surgical success (pain-free after at least 12 months) was compared between patients with a hyperacute SATNaPT and all other patients. RESULTS: Patients without a hyperacute SATNaPT had an 82% likelihood of surgical success, whereas patients with a hyperacute SATNaPT had a 58% likelihood of surgical success ( P < .05). Patients with a hyperacute SATNaPT who also had no evidence of vascular compression on preoperative MRI had an even lower likelihood of success (29%, P < .05). CONCLUSION: In patients with cTN being considered for MVD, a hyperacute SATNaPT is a negative prognostic biomarker that predicts a higher likelihood of surgical failure. Patients with a hyperacute SATNaPT, particularly those without MRI evidence of vascular compression, may benefit from other surgical treatments or a modification of MVD to adequately address the underlying cause of cTN.

Arrested Descent of the Thyroid: A New Manifestation of Abnormal Thyroid Embryology.

In this article, we review the normal embryology of the thyroid gland, categorize the ways in which this embryology can fail, and describe how those failures manifest clinically and radiologically. Finally, we describe a new manifestation of abnormal thyroid embryology. Laryngoscope, 134:995-997, 2024.

CT of the Larynx: Is an Additional High-Resolution Acquisition Necessary for Diagnostic Accuracy?

BACKGROUND AND PURPOSE: Diagnostic CT of the larynx is historically performed with a protocol that combines a standard neck CT with dedicated imaging through the larynx. Multichannel CT scanners, however, allow high-resolution reformatted images of the larynx to be created directly from the initial neck acquisition data. The purpose of this study was to determine whether reformatted laryngeal images derived from a standard neck CT acquisition provide information comparable with that of separate dedicated high-resolution laryngeal images. MATERIALS AND METHODS: The CT protocol for suspected laryngeal masses at our institution consists of a standard neck acquisition followed by a second acquisition focused on the larynx. We enrolled 200 patients who had undergone this protocol for a suspected laryngeal mass. Two head and neck radiologists independently reviewed each of the 200 scans twice. In one session, the entire scan was available, while in the other session, only images derived from the standard neck acquisition were available. The main outcome variable was the frequency of discrepant tumor staging between the interpretation sessions. No pathologic reference standard was used. RESULTS: Radiologist A had discrepant staging in 45 of the 200 scans (23%; 95% CI, 17%-29%). Radiologist B had discrepant staging in 42 of the 200 scans (21%; 95% CI, 16%-27%). Fifty-three of the 87 discrepancies (61%) reflected improper downstaging of the laryngeal tumor on standard images alone, while the other 34 (39%) had improper upstaging on standard images alone. CONCLUSIONS: Reformatted images from our institution's standard neck CT acquisition were less accurate than dedicated images of the larynx for analysis of laryngeal tumor extension. Focused images of the larynx were needed to optimize interpretation.

Prevalence of Cochlear-Facial and Other Non-Superior Semicircular Canal Third Window Dehiscence on High-Resolution Temporal Bone CT.

BACKGROUND AND PURPOSE: The radiologic prevalence of superior semicircular canal dehiscence in the asymptomatic population has been widely studied, but less is known about the rates of other forms of third window dehiscence. Per the existing literature, the radiologic prevalence of cochlear-facial nerve dehiscence, for example, exceeds that seen in histologic studies, suggesting that conventional CT is unreliable for cochlear-facial dehiscence. These studies relied on nonisometric CT acquisitions, however, and underused multiplanar reformatting techniques, leading to false-positive findings. Our purpose was to determine the rate of cochlear-facial dehiscence and other non-superior semicircular canal third window dehiscences on optimized CT in asymptomatic patients. MATERIALS AND METHODS: Sixty-four-channel temporal bone CT scans from 602 patients in emergency departments were assessed for cochlear-facial and other non-superior semicircular canal third window dehiscences by using high-resolution, multiplanar oblique reformats. Confidence intervals for dehiscence prevalence were calculated using the Newcombe 95% interval confidence method. RESULTS: Of 602 patients, 500 were asymptomatic, while 102 had an imaging indication consistent with possible third window syndrome (symptomatic). Eight asymptomatic patients (1.6%) had cochlear-facial dehiscence, while 43 (8.4%) had jugular bulb-vestibular aqueduct dehiscence. There was no statistically significant difference between the prevalence of cochlear-facial dehiscence or jugular bulb-vestibular aqueduct dehiscence in asymptomatic patients compared with symptomatic patients. Cochlear-carotid canal, cochlear-internal auditory canal, and cochlear-petrosal sinus dehiscences were not observed. CONCLUSIONS: Sixty-four-channel CT with multioblique reformatting is sensitive and specific for identifying cochlear-facial dehiscence, with rates similar to those in postmortem series. Jugular bulb-vestibular aqueduct dehiscence is a common incidental finding and is unlikely to produce third window physiology. Other non-superior semicircular canal third window dehiscences are rare in asymptomatic patients.

Hematoma Progression Rates on Head Computed Tomography for Fluid Levels versus Mimics in Patients with Primary Intracerebral Hemorrhage.

BACKGROUND: Among stroke patients, primary intracerebral hemorrhage has the highest mortality rate. Expansion of hematoma plays a prognostic role in these patients. Although fluid levels have been shown to predict subsequent hematoma expansion, there are mimics of fluid levels that may confuse interpretation. We hypothesized that patients with true fluid levels on head computed tomography (CT) have higher hematoma progression rates and worse outcomes compared with patients who have fluid level mimics on CT. METHODS: Adult patients presenting with intracerebral hemorrhage described as a fluid level on initial CT interpretation were included. Medical records were reviewed to extract relevant clinical variables. A CAQ-certified neuroradiologist retrospectively determined whether there was a true fluid level or mimic on CT and then evaluated follow-up CT scans for radiologic progression. We compared radiologic progression, mortality, and anticoagulation status between patients with true fluid levels and fluid level mimics. RESULTS: The study included 12 patients, 8 with true fluid levels and 4 with radiologic mimics. The patients with true fluid levels had a significantly higher likelihood of radiographic progression (P = 0.014). Differences in outcome, use of anticoagulation therapy, and average international normalized ratio were not significant. CONCLUSIONS: A fluid level within intraparenchymal hemorrhage on head CT scan is associated with higher likelihood of intracerebral hemorrhage progression. However, this applies only to true fluid levels, with mimics having a lower likelihood of progression. A careful analysis of potential fluid levels is necessary before assigning prognostic implications.

Persistent craniopharyngeal canal with an associated sphenoid sinus fistula.

Persistent craniopharyngeal canal (PCC) is a rare congenital anomaly that appears as a linear well-corticated canal running from the sella through the clivus and into the nasopharynx. Case reports of this anomaly have shown it is associated with a range of craniofacial defects, pituitary abnormalities, and meningoencephaloceles. It predisposes patients to bacterial meningitis. In this case a 46-year-old gentleman presenting for preoperative planning for surgical drainage of Potts Puffy tumor was found to have a PCC on CT and MRI. Imaging also demonstrated the presence of chronic inflammation and a fistula extending from the tract into the sphenoid sinus. This unusual presentation of a PCC with a sphenoid sinus fistula broadens the potential clinical presentations of PCC and further emphasizes the ability of this anomaly to serve as a conduit for CNS infection.

Cranial Nerve Anatomy.

The 12 cranial nerves (CNs) all have important functions. All, except the accessory nerve, arise solely within the cranial vault. We will discuss each CN function along with its entire CN course. The modality of choice for evaluation of the CN itself is typically MRI, however, CT is very important to access the bony foramina and CN boundaries..

Definitive local therapy to head and neck squamous cell carcinoma with distant metastasis.

Objectives: Data on the efficacy of including definitive local therapy to the primary site for head and neck squamous cell carcinoma (HNSCC) patients with synchronous distant metastasis are lacking. In multiple different solid tumor types, there has been benefit when using systemic therapy followed by local consolidative therapy (stereotactic ablative radiotherapy or surgery) directed at metastases. We proposed to retrospectively evaluate patients at our institution that received definitive treatment to the primary. Methods: Single institution retrospective study evaluating 40 patients with metastatic HNSCC treated with definitive surgery (55%) or chemoradiation (45%) to the primary site from 2000 to 2020. The major endpoints were overall survival (OS) and progression-free survival (PFS) for the total population and multiple sub-groups. Some variables were evaluated with multiple covariates Cox model. Results: The median PFS was 8.6 months (95% CI, 6.4-11.6), and OS was 14.2 months (95% CI, 10.9-27.5). In 28% of patients that received induction therapy, there was a twofold increase in median overall survival to 27.5 months. In the 33% of patients that received anti-PD-1 mAb as part of their treatment course, the median OS was significantly increased to 41.7 months (95% CI, 8.7-NR) versus 12.1 months (95% CI, 8.4-14.4) with a 5-year OS of 39%. Multivariate analysis for OS showed significance for age at diagnosis, use of IO, and number of metastatic sites. Conclusion: We observed impressive survival outcomes in metastatic HNSCC patients treated with definitive local therapy to the primary site in addition to induction and/or immunotherapy. Further study is warranted.Level of Evidence: 3.

Elexacaftor-Tezacaftor- Ivacaftor improves sinonasal outcomes in cystic fibrosis.

BACKGROUND: Many individuals with cystic fibrosis (CF) have chronic rhinosinusitis resulting in nasal obstruction, sinus infections, and repeated surgeries. Elexacaftor-tezacaftor-ivacaftor is a highly effective modulator therapy approved for individuals aged 6 years or older with CF who have at least one F508del allele or other responsive mutation. The current study tests the hypothesis that ELX/TEZ/IVA improves sinonasal disease in CF. METHODS: The study was a pre/post, observational cohort study conducted at two sites. Participants underwent a study visit prior to starting ELX/TEZ/IVA and a second visit at a median of 9 months on therapy. Each visit included sinus CT scan, rigid nasal endoscopy, and sweat chloride measurement. Symptoms were measured with the 22 item Sinonasal Outcome Test at scheduled intervals during the study. Regression models were used to test for improvement in symptoms, endoscopy, and CT scales. RESULTS: The study enrolled 34 individuals, with a median age of 27 years (range 12-60). Symptoms improved within 7 days of therapy and plateaued by day 28. Endoscopic crusting resolved and nasal polyposis improved, with a decrease in size or resolution of polyps. Sinus opacification and mucosal thickening improved on CT radiographs with treatment. CONCLUSIONS: Sinonasal symptoms improved rapidly and durably for at least 180 days on ELX/TEZ/IVA therapy. Objective measures of disease including endoscopic and CT findings improved with ELX/TEZ/IVA.

Chronic encapsulated expanding hematomas after stereotactic radiosurgery for intracranial arteriovenous malformations.

OBJECTIVE: Cerebral arteriovenous malformations (AVMs) are rare cerebral vascular lesions that are associated with high morbidity and mortality from hemorrhage; however, stereotactic radiosurgery (SRS) is a well-validated treatment modality. Few reports have delineated a subgroup of patients who develop delayed chronic encapsulated expanding hematomas (CEEHs) despite angiographic evidence of AVM obliteration following radiosurgery. In this report, the authors performed a retrospective review of more than 1000 radiosurgically treated intracranial AVM cases to delineate the incidence and management of this rare entity. METHODS: Between 1988 and 2019, 1010 patients with intracranial AVM underwent Gamma Knife SRS at the University of Pittsburgh Medical Center. In addition to a review of a prospective institutional database, the authors performed a retrospective chart review of the departmental AVM database to specifically identify patients with CEEH. Pertinent clinical and radiological characteristics as well as patient outcomes were recorded and analyzed. RESULTS: Nine hundred fifty patients with intracranial AVM (94%) had sufficient clinical follow-up for analysis. Of these, 6 patients with CEEH underwent delayed resection (incidence rate of 0.0045 event per person-year). These patients included 4 males and 2 females with a mean age of 45.3 ± 13.8 years at the time of initial SRS. Four patients had smaller AVM volumes (4.9-10 cm3), and 3 of them were treated with a single SRS procedure. Two patients had larger-volume AVMs (55 and 56 cm3), and both underwent multimodal management that included staged SRS and embolization. Time to initial recognition of the CEEH after initial SRS ranged between 66 and 243 months. The time between CEEH recognition and resection ranged from 2 to 9 months. Resection was required because of progressive neurological symptoms that correlated with imaging evidence of gradual hematoma expansion. All 6 patients had angiographically confirmed obliteration of their AVM. Pathology revealed a mixed chronicity hematoma with areas of fibrosed blood vessels and rare areas of neovascularization with immature blood vessels but no evidence of a persistent AVM. All 6 patients reported persistent clinical improvement after hematoma resection. CONCLUSIONS: CEEH after SRS for AVM is a rare complication with an incidence rate of 0.0045 event per person-year over the authors' 30-year experience. When clinical symptoms progress and imaging reveals progressive enlargement over time, complete resection of a CEEH results in significant clinical recovery. Knowledge of this rare entity facilitates timely detection and eventual surgical intervention to achieve optimal outcomes.

Interrater Reliability of NI-RADS on Posttreatment PET/Contrast-enhanced CT Scans in Head and Neck Squamous Cell Carcinoma.

Purpose To evaluate the interrater reliability among radiologists examining posttreatment head and neck squamous cell carcinoma (HNSCC) fluorodeoxyglucose PET/contrast-enhanced CT (CECT) scans using Neck Imaging Reporting and Data System (NI-RADS). Materials and Methods In this retrospective study, images in 80 patients with HNSCC who underwent posttreatment surveillance PET/CECT and immediate prior comparison CECT or PET/CECT (from June 2014 to July 2016) were uploaded to the American College of Radiology's cloud-based website, Cortex. Eight radiologists from seven institutions with variable NI-RADS experience independently evaluated each case and assigned an appropriate prose description and NI-RADS category for the primary site and the neck site. Five of these individuals were experienced readers (> 5 years of experience), and three were novices (< 5 years of experience). In total, 640 lexicon-based and NI-RADS categories were assigned to lesions among the 80 included patients by the eight radiologists. Light generalization of Cohen κ for interrater reliability was performed. Results Of the 80 included patients (mean age, 63 years ± 10 [standard deviation]), there were 58 men (73%); 60 patients had stage IV HNSCC (75%), and the most common tumor location was oropharynx (n = 32; 40%). Light κ for lexicon was 0.30 (95% CI: 0.23, 0.36) at the primary site and 0.31 (95% CI: 0.24, 0.37) at the neck site. Light κ for NI-RADS category was 0.55 (95% CI: 0.46, 0.63) at the primary site and 0.60 (95% CI: 0.48, 0.69) at the neck site. Percent agreement between lexicon and correlative NI-RADS category was 84.4% (540 of 640) at the primary site and 92.6% (593 of 640) at the neck site. There was no significant difference in interobserver agreement among the experienced versus novice raters. Conclusion Moderate agreement was achieved among eight radiologists using NI-RADS at posttreatment HNSCC surveillance imaging. Keywords: CT, PET/CT, Head/Neck, Neck, Neoplasms-Primary, Observer Performance Supplemental material is available for this article. © RSNA, 2021.

Epidural Contrast Volume on Post-Myelogram Lumbar CT Predicts the Rate of Subsequent Blood Patch Treatment.

BACKGROUND AND PURPOSE: Headaches due to cerebrospinal fluid (CSF) leakage are a well-known complication of dural puncture. The purpose of this study was to determine whether the presence and volume of epidural contrast on postmyelogram CTs of the lumbar spine were associated with post-dural puncture headaches (PDPHs) requiring epidural blood patch (EBP) treatment. METHODS: A retrospective case control study of all fluoroscopically guided lumbar myelograms performed over a 5-year period by a single radiology practitioner assistant was performed. Ten patients who underwent EBP treatment after their myelograms were identified. Forty-six patients with similar demographics who did not receive blood patches were then selected. CT-lumbar myelogram images of patients and controls were reviewed. The volume of epidural contrast was then quantified as "severe" or "mild." Severe epidural contrast was defined as contrast detected in the ventral epidural space, the extra-foraminal space, or extending greater than or equal to the length of two vertebral bodies from the level of dural puncture. RESULTS: Some amount of epidural contrast was seen in all patients. However, a severe volume of epidural contrast was associated with increased risk for PDPH requiring an EBP (odds ratio = 37.00; 95% CI = 4.1-330.8, p = 0.0012). CONCLUSION: Severe epidural contrast on postmyelogram CTs of the lumbar spine was associated with an increased risk of PDPH requiring EBP treatment. When present, this finding can alert the proceduralist that the patient may require closer observation and follow up with earlier intervention.