Updated Imaging Features of Dysplastic Cerebellar Gangliocytoma.

OBJECTIVE: The aim of this study was to perform an updated review of the imaging features of dysplastic cerebellar gangliocytoma (DCG). METHODS: Imaging findings were retrospectively reviewed in 14 patients with DCG. The analysis included size, location, cyst formation, calcification, intralesional hemorrhage, enhancement pattern, and apparent diffusion coefficient (ADC). RESULTS: In addition to revisiting many well-established imaging features of DCG, enhancement was much more common (64.3%) than previously reported, and small enhancing veins were also frequently encountered within or along the periphery of the lesions (50%). Dysplastic cerebellar gangliocytomas had an elevated ADC compared with normal cerebellum (967.8 ± 115.7 vs 770.4 ± 47.3 × 10 mm/s; P < 0.0001). CONCLUSIONS: Enhancement on magnetic resonance imaging within DCG should be an accepted imaging finding rather than being viewed as uncommon or atypical. Dysplastic cerebellar gangliocytomas typically have an elevated ADC compared with normal cerebellum, which may assist in differentiation from other posterior fossa neoplasms.

Computed Tomography-Based Texture Analysis to Determine Human Papillomavirus Status of Oropharyngeal Squamous Cell Carcinoma.

OBJECTIVE: To determine whether machine learning can accurately classify human papillomavirus (HPV) status of oropharyngeal squamous cell carcinoma (OPSCC) using computed tomography (CT)-based texture analysis. METHODS: Texture analyses were retrospectively applied to regions of interest from OPSCC primary tumors on contrast-enhanced neck CT, and machine learning was used to create a model that classified HPV status with the highest accuracy. Results were compared against the blinded review of 2 neuroradiologists. RESULTS: The HPV-positive (n = 92) and -negative (n = 15) cohorts were well matched clinically. Neuroradiologist classification accuracies for HPV status (44.9%, 55.1%) were not significantly different (P = 0.13), and there was a lack of agreement between the 2 neuroradiologists (κ = -0.145). The best machine learning model had an accuracy of 75.7%, which was greater than either neuroradiologist (P < 0.001, P = 0.002). CONCLUSIONS: Useful diagnostic information regarding HPV infection can be extracted from the CT appearance of OPSCC beyond what is apparent to the trained human eye.

Hypoglossal Canal Lesions: Distinctive Imaging Features and Simple Diagnostic Algorithm.

OBJECTIVE: The objective of this study is to compare the prevalence of hypoglossal canal lesions and identify differentiating imaging features. MATERIALS AND METHODS: A 15-year retrospective review of lesions of the hypoglossal nerve and hypoglossal canal, excluding those in patients with metastasis or prior head and neck cancer and those treated with radiation or surgery, was performed. Clinical findings and lesion imaging features were documented. The contrast-enhanced T1-weighted nonenhancing cystic component of hypoglossal schwannomas was compared with size-matched pathologically proven vestibular schwannomas. RESULTS: Our review identified 40 lesions encroaching on the hypoglossal canal, located within the hypoglossal canal, or found in both locations: 16 hypoglossal schwannomas, 15 juxtaarticular cysts, and nine purely cystic hypoglossal canal lesions. Hypoglossal schwannomas, which were intradural when involving the premedullary cistern, most commonly enhanced heterogeneously, with a thick peripheral enhancing component, a central enhancing component, or both enhancing components. Juxtaarticular cysts encroaching on the hypoglossal canal were extradural, were contiguous with a craniocervical junction synovial joint, and showed thin rim enhancement. Hypoglossal canal nonenhancing cystic lesions were confined to the hypoglossal canal, had signal intensity equivalent to CSF, and lacked any contrast enhancement. CONCLUSION: Although hypoglossal schwannomas, juxtaarticular cysts, and hypoglossal canal nonenhancing cystic lesions may all encroach on or lie within the hypoglossal canal, purely cystic lesions are unlikely to be schwannomas. A diagnostic algorithm applying key imaging and clinical findings allows differentiation of these lesions, which have vastly different treatment regimens.

Imaging characteristics and clinical outcomes of biphenotypic sinonasal sarcoma.

OBJECTIVES: Biphenotypic sinonasal sarcoma (BSS) is a new, rare tumor characterized by concomitant neural and myogenic differentiation. The aim of this study is to describe the imaging characteristics and clinical outcomes of this neoplasm. METHODS: A retrospective review of BSS patients surgically treated within a tertiary academic health care system was performed. Imaging characteristics and clinical outcomes were reviewed. RESULTS: Five patients underwent surgical resection of BSS tumors. Negative surgical margins were achieved in four (80%) patients. There were no deaths but two (40%) patients developed local recurrences during the postoperative follow-up period (median follow-up 31.4 months). Review of imaging characteristics revealed a median tumor size of 3.8 cm in greatest dimension. All tumors were unilateral and centered within the nasoethmoidal region. In all cases, the tumors extended to the nasal septum, lamina papyracea, and anterior skull base with variable degrees of erosion through these structures. On CT, involved bony structures demonstrated mixed lytic and sclerotic pattern, with definitive hyperostotic bone identified in four (80%) cases. On MRI, tumors were isointense-to-mixed iso/hypointense on both T1- and T2-weighted sequences with one tumor demonstrating mixed T2 hyperintensity. All cases demonstrated gadolinium contrast enhancement. CONCLUSIONS: BSS is a locally aggressive tumor with a low risk of regional or distant metastases but has a significant rate of recurrence even with adequate resection. Despite its rarity, BSS should be considered in the differential diagnosis when imaging demonstrates a unilateral nasoethmoidal mass that is predominantly isointense to cerebral gray matter on T2-weighted MRI and is hyperostotic on CT. LEVEL OF EVIDENCE: 4.

Facial nerve venous malformation: A radiologic and histopathologic review of 11 cases.

OBJECTIVE: The purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve "hemangiomas" to confirm that these lesions are most characteristic of venous malformations rather than neoplasms. STUDY DESIGN: Retrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed. MATERIALS AND METHODS: A panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1). RESULTS: Lesions were composed of dilated vascular spaces with a simple, CD31-positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common. CONCLUSIONS: On the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations. LEVEL OF EVIDENCE: 4.

Neuroimaging abnormalities in patients with Cowden syndrome: Retrospective single-center study.

BACKGROUND: We retrospectively reviewed the neuroimaging findings of patients with Cowden syndrome and determined their frequency in a single cohort. METHODS: Electronic medical records were queried from January 1999 to January 2017 to identify patients who fit the clinical criteria for diagnosis of Cowden syndrome with or without a documented PTEN mutation. Patients with brain MRI examinations were then identified. RESULTS: We retrospectively identified 44 patients with Cowden syndrome, 22 of whom had neuroimaging for review. Eleven (50%) had Lhermitte-Duclos disease, 4 (18.1%) had meningiomas, 13 (59.1%) had at least one developmental venous anomaly, 3 had cavernous malformations, 2 had evidence of dural arteriovenous fistula, 7 had increased white matter signal abnormalities relative to age (31.8%), 4 had prominent perivascular spaces, cerebellar tonsillar ectopia was present in 7 of 21 (33.3%), and 1 had cortical malformation. CONCLUSIONS: It is important to recognize that in addition to Lhermitte-Duclos disease, other intracranial findings such as multiple venous anomalies, meningiomas, greater than expected white matter signal abnormality, prominent perivascular spaces, and cortical malformations may warrant a thorough evaluation for Cowden syndrome in the appropriate clinical setting. We further recommend that this broader spectrum of intracranial abnormalities be considered for addition to the Cowden syndrome diagnostic criteria at the time of next revision.

Normal Variant Occipital Pneumatization.

OBJECTIVE: Evaluate prevalence and pattern of occipital pneumatization (OP). PATIENTS: Individuals with imaging evidence of OP on computed tomography (CT). INTERVENTION(S): High resolution CT scans of the temporal bone. MAIN OUTCOME MEASURE: The prevalence and pattern of OP on 1000 CT scans performed at a large academic healthcare system. RESULTS: OP had a prevalence of 11.8% (n = 118) while occipital condyle pneumatization occurred in only 0.3%. Occipital air cells were right-sided in 27.1% (n = 32), left-sided in 51.7% (n = 61), and bilateral in 21.2% (n = 25), and OP was contiguous with the occipitomastoid suture. In cases of unilateral OP, the contralateral jugular foramen demonstrated relative enlargement (p = 0.006), but a direct association could not be established. CONCLUSIONS: The occipital bone is an accessory site of skull base pneumatization in 11.8% of the population undergoing temporal bone CT, while air cell extension into the occipital condyle occurs more rarely. These occipital air cells have a left-sided predilection and are always in direct proximity to the occipitomastoid suture, suggesting developmental egress from the mastoid. OP is a normal variant and lacks features of craniocervical pneumatization, which is a rare disorder.

Brain injury after cardiopulmonary arrest and its assessment with diffusion-weighted magnetic resonance imaging.

OBJECTIVE: To characterize the frequency and pattern of diffusion-weighted imaging (DWI) abnormalities detected as part of brain magnetic resonance imaging (MRI) and their association with short-term neurologic outcomes in patients successfully resuscitated after cardiopulmonary arrest (CPA). PATIENTS AND METHODS: We retrospectively analyzed a case series of patients who experienced CPA between May 1, 2000, and April 29, 2004, at St Luke's Hospital in Jacksonville, Fla. Eligible patients required treatment by the Code Blue team and had 1 DWI study before discharge or death. Two neuroradiologists jointly classified DWI abnormalities by anatomic location. Outcome was measured by Cerebral Performance Category score. RESULTS: Resuscitation was performed 628 times during the 48-month study period. Of 514 CPA survivors, 18 (3.5%) had MRI studies. The median age was 62 years (interquartile range [IQR], 49-73), and 10 were men. Median code duration was 16 minutes (IQR, 11-19 minutes), and median code-to-scan time was 72 hours (IQR, 28-229 hours). A DWI abnormality was noted in 9 (50%) of 18 patients. Cortical areas (global and regional) were the most common sites of restricted diffusion. Diffusion-weighted imaging abnormalities were present in 7 (70%) of 10 patients with a poor neurologic outcome at discharge. CONCLUSION: Magnetic resonance imaging is performed rarely after survival of CPA. In this study with limited sample size, a greater proportion of patients with normal DWI findings had a good neurologic outcome at the time of hospital discharge vs those with abnormal findings. Prospective studies of early and serial MRI (with DWI) are needed to confirm this association and to clarify the prognostic usefulness of such studies.

Diagnosing Large Vestibular Aqueduct: Radiological Review of High-Resolution CT Versus High-Resolution Volumetric MRI.

OBJECTIVES: To compare the diagnostic yield of high-resolution volumetric T2-weighted MRI (HRT2-MRI) with high-resolution computed tomography (HRCT) for diagnosis of large vestibular aqueduct (LVA). STUDY DESIGN: Three board-certified neuroradiologists performed an independent, blinded radiological review for diagnosing LVA with 2:1 age-matched controls on patients with both HRCT and HRT2-MRI imaging. SETTING: Tertiary referral center. PATIENTS: All patients between 2002 and 2016 with hearing loss who underwent both HRCT and HRT2-MRI and were diagnosed with LVA on either modality. MAIN OUTCOME MEASURES: Concordance rate for LVA between HRCT and HRT2-MRI. RESULTS: Concordance rate for HRCT and HRT2-MRI for diagnosing LVA was 88% (124/141) when assessing both the midpoint and external aperture diameters. Fifteen ears had LVA on computed tomography (CT), but not on magnetic resonance imaging (MRI); in comparison, two ears had LVA on MRI, but not on CT (p = 0.002). Excellent inter-rater reliability among the three radiologists was demonstrated. CONCLUSION: Historically, HRCT has been the imaging modality of choice for diagnosing LVA. Although a higher concordance rate of HRT2-MRI was found compared with previous studies utilizing earlier MRI technology, HRCT still detected a larger number of patients with clinically significant hearing loss compared with MRI. Given the high concordance rate and efficacy of both modalities in diagnosing LVA, the ultimate decision of which modality to choose may depend on other patient-specific and clinical factors.

Craniocervical Pneumatization: Estimation of Prevalence and Imaging of Treatment Response.

OBJECTIVE: Estimate the prevalence of craniocervical pneumatization (CCP) and describe successful treatment of this condition with clinical and radiologic correlation. PATIENTS: Individuals with documented CCP on computed tomography (CT). INTERVENTION(S): CT scans of the head, temporal bone, face, neck, and cervical spine. Cessation of habitual Valsalva maneuver (VM) and insertion of pressure-equalization (PE) tubes. MAIN OUTCOME MEASURE: The prevalence of CCP on CT examinations performed during two decades in a large academic healthcare system. Documentation of symptomatic and imaging improvement following treatment of CCP. RESULTS: Radiology database review identified two cases of CCP out of a total of 636,854 head and neck CT scans (0.00031%) or 43,553 temporal bone CT scans (0.0046%). Both CCP patients were symptomatic (aural fullness, hearing loss, vertigo) and practiced habitual VM. One patient showed decreased CCP 4 months following cessation of VM, whereas the other patient improved symptomatically and demonstrated reversion of CCP to normal bone on magnetic resonance imaging (MRI) within 3 years following PE tube placement. CONCLUSIONS: Acquired CCP is exceedingly rare and, when successfully treated, reversion to normal bone may accompany symptom resolution.

Maxillary sinus angiomyolipoma: A case report and overview.

Otolaryngologists are called upon to evaluate and treat sinonasal masses discovered incidentally on imaging studies. Although common conditions such as sinonasal polyps and mucus retention cysts predominate, it is prudent practice to formulate a differential diagnosis to identify unusual conditions. We present a case of a maxillary sinus mass in a 78-year-old man that was discovered incidentally on brain imaging and subsequently identified on biopsy as an angiomyolipoma (AML). AMLs are benign hamartomatous tumors that rarely occur in extrarenal locations. Only a few cases have been reported in the nasal cavity. We believe our case represents the first reported instance of AML arising within a maxillary sinus. Identification of intratumoral fat within the mass on imaging studies may suggest the diagnosis of AML preoperatively. Close interdisciplinary collaboration among the otorhinolaryngology, radiology, and pathology services is beneficial for patient management. We report this case to raise awareness that AML can arise in this previously unreported location. Moreover, we wish to emphasize that AML should be considered in the differential diagnosis when imaging studies demonstrate a well-defined, heterogeneous, fat-containing solitary mass in the nasal cavity or maxillary sinus.

Computed tomographic angiography with three-dimensional reconstruction for transoral laser microsurgery.

OBJECTIVE: To identify major arteries in relationship to large pharyngeal tumors during transoral laser microsurgery. STUDY DESIGN: Case series with planned data collection. SETTING: Mayo Clinic, Jacksonville, Florida. SUBJECTS AND METHODS: We developed a new technique that combines three-dimensional CT angiography and enhanced soft-tissue neck CT for evaluation of pharyngeal tumors before transoral laser microsurgery. Data from CT angiography were used to create three-dimensional images of the tumor and adjacent arterial branches to better orient the surgeon to the spatial relationships of major arteries and pharyngeal tumors. Included were selected patients who had large tumors involving the pharynx and who underwent transoral laser microsurgery. RESULTS: Eighteen patients were studied from June 2008 through January 2009. Tumor enhancement was absent or modest in four of 18 patients. Three of these four patients had superficial squamous cell carcinomas and one had adenoid cystic carcinoma. The remaining 14 patients had good tumor enhancement. The tumor involved the lingual artery in three and displaced the lingual or facial artery in two of these 14 patients. One anomalous right inferior thyroid artery was identified. Compared with routine enhanced soft-tissue neck CT, three-dimensional CT angiography greatly enhanced the anatomical relationships of the major arteries. In one patient, the surgeon's approach was changed after three-dimensional CT angiography demonstrated an encased lingual artery. CONCLUSION: Three-dimensional CT angiography was useful in identifying the anatomical orientation of major arteries and the planning of transoral laser microsurgery to treat tumors involving the pharynx.

Spontaneous craniospinal hypotension.

Spontaneous cerebrospinal fluid (CSF) leak has been called "spontaneous intracranial hypotension," emphasizing the intracranial symptoms and imaging findings. We present a patient with spontaneous CSF leak whose initial spinal magnetic resonance imaging (MRI) findings were thought to represent epidural tumor or infection. Subsequent MRI examinations showed an improvement of both intracranial and spinal CSF hypotension findings coinciding with clinical symptom resolution. We propose the term "spontaneous craniospinal hypotension" to better emphasize this syndrome's unifying intracranial and spinal pathophysiology and imaging findings.