Determination of posterolateral oropharyngeal wall thickness and the potential implications for transoral surgical margins in tonsil cancer.

BACKGROUND: Margins in transoral surgery for tonsil cancer can be limited by oropharyngeal wall thickness (OWT), but the normal range is not well established. METHODS: In 240 noncancer subjects, OWT was measured bilaterally in the vicinity of the tonsils with MRI. Statistical analysis was performed to assess for interaction of age, sex, location, and obesity. RESULTS: Mean(SD) OWT measured 3.4(0.6) mm posteriorly, 3.7(2.0) mm between the styloglossus and stylopharyngeus, and 5.3(0.8) mm laterally. OWT was greater in men, correlated with obesity, decreased posteriorly and laterally in the 60-80 versus 40-59 year age groups, and increased when styloglossus/stylopharyngeus were closer. OWT was <5 mm in 36.7%-97.9% of locations, with the largest percentage below this threshold located posteriorly. CONCLUSIONS: OWT is frequently <5 mm, particularly in the posterior and intermuscular areas, suggesting that a smaller surgical margin may need to be accepted in transoral tonsil cancer surgery for anatomic reasons.

Analysis of MRI Volumetric Changes After Hypofractionated Stereotactic Radiation Therapy for Benign Intracranial Neoplasms.

PURPOSE: To quantitatively assess volumetric changes after hypofractionated stereotactic radiation therapy (HFSRT) in patients treated for vestibular schwannomas and meningiomas. METHODS AND MATERIALS: We retrospectively reviewed records of patients treated with HFSRT at our institution from 2002 to 2014. Patients received a median dose of 25 Gy in 5 fractions. After treatment, they underwent clinical and radiologic follow-up with magnetic resonance imaging (MRI) at 3- to 12-month intervals. Gross tumor volume was outlined on each thin slice of contrast-enhanced T1 series before and on each scan after HFSRT. Volumetric changes were calculated and compared with neuroradiologist interpretations. RESULTS: Forty-three patients underwent 182 MRI scans. Tumor types included vestibular schwannoma (n = 34) and meningioma (n = 9). Median follow-up time was 29 months. Median gross tumor volume was 3.1 cm3. Local control was 81.4% for the entire cohort at the time of last follow-up. Transient volume expansion was noted in 17 patients (50%) with vestibular schwannoma and 2 (22%) with meningioma. For all patients, transient volume expansion and subsequent regression occurred at a median time of 5.5 and 12 months, respectively. Neuroradiologist agreement with regard to tumor regression, progression, or stability occurred in 155 of 182 total reports (85%). The largest discordance identified was a stable finding on the MRI interpretation when the measured volumetric change exceeded 20% (n = 24 [13%]). CONCLUSIONS: HFSRT is associated with excellent local control and a low incidence of toxicity. With volumetric MRI measurement, transient volume expansion was a common finding and was associated with temporary adverse effects. Although the neuroradiologist's interpretation generally agreed with the volumetric MRI measurement, the overall 15% discordance rate emphasizes the potential benefit of considering volumetric measurements, which may help clinicians correlate posttreatment symptoms with MRI findings.

Magnetic Resonance Imaging Assessment of Vascular Contact of the Facial Nerve in the Asymptomatic Patient.

Objective The objective of this study was to determine the prevalence of facial nerve vascular contact on magnetic resonance imaging (MRI) in patients without hemifacial spasm (HFS). Study Design Our radiology database was queried to identify consecutive adult patients without a history of HFS, intracranial tumor, brain radiation therapy, intracranial surgery, traumatic brain injury, or trigeminal nerve vascular compression. One hundred high-resolution MRIs of the posterior fossa were independently reviewed by two neuroradiologists for facial nerve vascular contact (200 sides). Main Outcome Measures The prevalence of vascular nerve contact in the non-HFS patient, the location of contact along the facial nerve, the culprit vessel, and severity of compression was recorded. Results The presence of vascular contact in the non-HFS patient may be as high as 53%. It is typically mild to moderate in severity, most commonly involves the cisternal portion, and usually caused by the anterior inferior cerebellar artery. Conclusion Vascular contact of the facial nerve is frequently identified in asymptomatic individuals but tends to be more peripheral and mild compared with previous descriptions of neurovascular contact in HFS patients. These results should be considered in assessing the candidacy of HFS patients for microvascular decompression.

PET/CT imaging of conus medullaris metastasis from lung cancer.

An intradural extramedullary metastasis is usually detected at an advanced stage of the disease or during workup for manifestations of spinal cord compression. Early diagnosis of such a lesion is rare and mostly fortuitous. The authors present a case of treated nonsmall cell lung carcinoma with an asymptomatic conus medullaris metastasis, which was demonstrated by PET/CT imaging during restaging evaluation.