Perineural spread in head and neck malignancies: clinical significance and evaluation with 18F-FDG PET/CT.

Certain tumors of the head and neck use peripheral nerves as a direct conduit for tumor growth away from the primary site by a process known as perineural spread. Perineural spread is associated with decreased survival and a higher risk of local recurrence and metastasis. Radiologists play an important role in the assessment and management of head and neck cancer, and positron emission tomography/computed tomography (PET/CT) with 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) is part of the work-up and follow-up of many affected patients. Awareness of abnormal FDG uptake patterns within the head and neck is fundamental for diagnosing perineural spread. The cranial nerves most commonly affected by perineural spread are the trigeminal and facial nerves. Risk of perineural spread increases with a midface location of the tumor, male gender, increasing tumor size, recurrence after treatment, and poor histologic differentiation. Focal or linear increased FDG uptake along the V2 division of the trigeminal nerve or along the medial surface of the mandible, or asymmetric activity in the masticator space, foramen ovale, or Meckel cave should raise suspicion for perineural spread. If FDG PET/CT findings suggest perineural spread, the radiologist should look at available results of other imaging studies, especially magnetic resonance imaging, to confirm the diagnosis. Knowledge of common FDG PET/CT patterns of neoplastic involvement along the cranial nerves and potential diagnostic pitfalls is of the utmost importance for adequate staging and treatment planning.

ECG-gated cardiac MDCT for detection of systolic anterior motion of mitral valve.

OBJECTIVES: Evaluating ECG-gated cardiac MDCT detection of systolic anterior motion of the mitral valve, in comparison to trans-thoracic echocardiography as a gold standard. MATERIALS AND METHODS: Study group included 83 consecutive patients (57 men; average age 56.1 years) evaluated with both retrospective ECG-gated cardiac MDCT and trans-thoracic echocardiography within an interval of 30 days. ECG-gated cardiac MDCT imaging was performed with retrospective ECG- gating using 64-slice and 128-slice CT scanners with an inherent temporal resolution range of 75-165 ms. MDCT's and trans- thoracic echocardiograms were retrospectively and independently evaluated by experienced radiologist and cardiologist respectively, for presence of systolic anterior motion of the mitral valve. RESULTS: 7 patients (8.4%) were found to have systolic anterior motion by trans-thoracic echocardiography, from which 6 were found to have systolic anterior motion by ECG-gated cardiac MDCT. Of the 76 patients without systolic anterior motion on trans-thoracic echocardiography, all were correctly identified using ECG-gated cardiac MDCT. The sensitivity, specificity, positive and negative predictive values and accuracy of ECG-gated cardiac MDCT in identifying systolic anterior motion of the mitral valve were 85.7% (6/7), 100% (76/76), 100% (6/6), 98.7% (76/77) and 98.8% (82/83), respectively. CONCLUSION: ECG-gated cardiac MDCT is comparable to trans-thoracic echocardiography in detecting systolic anterior motion of the mitral valve.

Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica.

INTRODUCTION: Empty sella in MRI is an important finding associated with idiopathic intracranial hypertension (IIH). This study assesses the sensitivity and reproducibility of several morphological measures of the sella and pituitary gland to indentify the measure that best differentiates IIH from controls. Additionally, the study assesses reversal in gland compression following treatment. METHODS: Sagittal 3D-T1W sequence with 1 mm isotropic resolution was obtained from ten newly diagnosed IIH patients and 11 matched healthy controls. Follow-up MRI scans were obtained from eight patients at 1-week post-lumbar puncture and acetazolamide treatment. 1D and 2D measures of absolute and normalized heights and cross-sectional areas of the gland and sella were obtained to identify the measure that best differentiates IIH patients and controls. RESULTS: Overall area-based measurements had higher sensitivity than length with p < 0.0001 for sella area compared with p = 0.004 for normalized gland height. The gland cross-sectional areas were similar in both cohorts (p = 0.557), while the sella area was significantly larger in IIH, 200 ± 24 versus 124 ± 25 mm(2), with the highest sensitivity and specificity, 100% and 90.9%, respectively. Absolute gland area was the most sensitive measure for assessing post treatment changes, with 100% sensitivity and 50 % specificity. Average post-treatment gland area was 18% larger (p = 0.016). Yet, all eight patients remained within the empty sella range based on a normalized gland area threshold of 0.41. CONCLUSIONS: Sellar area is larger in IIH, and it demonstrated highest sensitivity for differentiating IIH from control subjects, while absolute gland area was more sensitive for detecting post treatment changes.