Cross-sectional imaging evaluation of atypical and uncommon extra-nodal head and neck Non-Hodgkin lymphoma: Case series.

Extra-nodal Non-Hodgkin lymphoma (ENHL) of the head and neck is not uncommon and has variable clinical and imaging presentations. It represents about 25% of extra-nodal lymphomas. In addition, lymphoma is the third most common malignancy of the head and neck just after squamous cell carcinoma (SCC) and salivary gland neoplasms. Unlike SCC, ENHL usually presents as a well-defined mass in the oral cavity, along the pharyngeal mucosa, sinonasal cavity, orbit, and other different neck spaces. One of the common presentations of ENHL is the glandular type which can arise within the salivary or thyroid glands as marginal zone non-Hodgkin lymphoma. ENHL can infiltrate the bone resembling high grade osseous malignancies. Rarely, ENHL can present as perineural spread without definitive mass and manifest clinically with several neuropathies. In this case series, we presented different imaging features and presentation of ENHL of the head and neck. The knowledge of various presentations of ENHL of the head and neck can help early diagnosis and prompt management of these patients' population.

Multi-parametric magnetic resonance imaging evaluation of cerebral amyloid angiopathy related inflammation: Case series and review of literature.

Cerebral amyloid angiopathy related inflammation is a rare disorder in the spectrum of cerebral amyloid angiopathy which is characterized by vascular and/or perivascular inflammation related to Aß deposits. Clinically, the patient typically presents with acute to subacute encephalitis-like symptoms with focal neurological deficits, rapidly cognitive decline, and/or seizures. Typical magnetic resonance imaging findings include asymmetric mass-like non-enhancing white matter hyperintensity with scattered microhemorrhages. Additionally, in these cases diffusion weighted imaging, perfusion weighted imaging and magnetic resonance spectroscopy help to exclude neoplastic processes and could determine the correct diagnosis.

Accuracy of combined quantitative diffusion-weighted MRI and routine contrast-enhanced MRI in discrimination of benign and malignant salivary gland tumors.

BACKGROUND: Preoperative imaging of salivary gland tumors is important for predicting and differentiating benign from malignant tumors, and for aiding management planning. We aimed to investigate the accuracy of combined quantitative diffusion-weighted magnetic resonance imaging (MRI) and routine contrast-enhanced MRI in the evaluation of salivary gland tumors and the differentiation of benign from malignant tumors. RESULTS: This study included 51 patients with a total of 16 benign and 35 malignant lesions that were detected by histopathological analysis. There was a statistically significant difference between the apparent diffusion coefficient values (ADC) of malignant and benign lesions (0.69 ± 0.22 × 10-3 mm2/s and 1.39 ± 0.52 × 10-3 mm2/s respectively). The optimal cut-off ADC value was 1.08 with 75% specificity and 97% sensitivity. The routine contrast-enhanced MRI had predicted benign and malignant tumors with 65% sensitivity and 44% specificity. The sensitivity and specificity were greatly increased when quantitative diffusion-weighted MRI was combined with routine contrast-enhanced MRI: 100%, and 88% respectively. A receiver operating curve was generated. The area under curve was 0.88 (p < 0.001, 95% CI: 0.76-0.99). CONCLUSION: Combined quantitative diffusion-weighted MRI with ADC measurements and routine contrast-enhanced magnetic resonance imaging are helpful tools for the evaluation of salivary gland tumors and help differentiate benign from malignant lesions.

Characterization of pediatric head and neck masses with quantitative analysis of diffusion-weighted imaging and measurement of apparent diffusion coefficients.

PURPOSE: Our objective was to investigate the accuracy of quantitative diffusion-weighted imaging (DWI) to determine the histopathologic diagnosis of pediatric head and neck lesions. MATERIALS AND METHODS: This retrospective study included 100 pediatric patients recently diagnosed with head and neck tumors. All patients underwent preoperative conventional magnetic resonance imaging (MRI) and DWI. Each lesion was evaluated according to signal characteristics, enhancement pattern, and diffusivity. The average apparent diffusion coefficient (ADC) obtained from each tumor was compared to the histological diagnosis of benign, locally malignant, or malignant categories. RESULTS: Our retrospective study showed a significant negative correlation between average ADC and tumor histopathologic diagnosis (P < 0.001, r = -0.54). The mean ADC values of benign, locally malignant lesions, and malignant tumors were 1.65 ± 0.58 × 10-3, 1.43 ± 0.17 × 10-3, and 0.83 ± 0.23 × 10-3 mm2 s-1, respectively. The ADC values of benign and locally malignant lesions were overlapped. We found a cut-off value of ≥1.19 × 10-3 mm2s-1 to differentiate benign from malignant pediatric head and neck masses with a sensitivity of 97.3%, specificity of 80.0%, positive predictive value of 94.7%, and negative predictive value of 88.9%. CONCLUSION: Diffusion-weighted MRI study is an accurate, fast, noninvasive, and nonenhanced technique that can be used to characterize head and neck lesions. DWI helps to differentiate malignant from benign lesions based on calculated ADC values. Additionally, DWI is helpful to guide biopsy target sites and decrease the rate of unnecessary invasive procedures.