MR and CT imaging features of sino-nasal organized hematomas.

AIM: To describe the MR and CT imaging features of organized hematomas [OH]. METHODS: A retrospective analysis of MR imaging and CT of eight patients [6 male, 2 females; age range is 6-86 years] with pathological proven OH was performed. Routine contrast MR and CT scan were done for all patients, and diffusion-weighted imaging and dynamic contrast CT were done for only five patients. Imaging analysis was done for the signal intensity, the enhancement pattern at MR imaging, the ADC value at DWI, bone remodeling at CT, and the neo-vascularization at dynamic contrast CT. RESULTS: OH revealed T2 hypo-intense of the matrix in all patients with complete [n = 3] and incomplete [n = 5] marginal hypo-intensity rim. The lesions revealed a frond-like pattern of contrast enhancement of the central part of the lesion that associated with a peripheral rim of contrast enhancement. OH revealed unrestricted diffusion with high ADC value [1.7-2.5 × 10-3 cm2/s] in 5 patients. CT scan showed geographic bone remodeling and thinning of the nasal turbinates, and the sinus wall and contrast CT showed neo-vascularization with frond-like branching arteries of the central part of the lesions in five patients. CONCLUSION: We conclude that MR and CT imaging findings can help in the diagnosis of OH.

Role of dynamic sleep MRI in obstructive sleep apnea syndrome.

PURPOSE: To identify obstruction sites of the upper airway during sleep in patients with obstructive sleep apnea syndrome (OSAS) under dynamic conditions and improve knowledge to guide surgical treatment and advancements. MATERIALS AND METHODS: The study included 15 patients (5 females and 10 males) who were diagnosed as having OSAS. Overall mean age was 40.2 years (± 7.01 years). All the patients underwent drug-induced sleep endoscopy (DISE) and dynamic sleep MRI. The presence, location, and direction of airway collapse were assessed. Dynamic MRI findings were correlated to DISE. Data of the site and direction of airway collapse were correlated with those of endoscopic findings and interobserver agreement was done. RESULTS: The dynamic images in sagittal section showed collapse of the upper airway at retropalatal level in 14 patients (93.33%) and at retroglossal level in seven patients (46.7%) and of these 14 patients; seven had combined retropalatal and retroglossal collapse. These findings were highly correlated with DISE findings with an excellent interobserver agreement for retropalatal and retroglossal levels (Kappa = 1 and 0.867, P value = 0.000), respectively. Objective measurements of the direction of collapse in axial dynamic sleep MRI images showed significant statistical correlation with endoscopic findings regarding retropalatal anteroposterior and circumferential collapse (Kappa = 0.58 and 0.52, P value = 0.02 and 0.03, respectively). CONCLUSION: Dynamic sleep MRI can reliably characterize the actual site of dynamic airway obstruction and has the potential of improving predictions of successful surgical outcomes in OSAS patients.

Arterial spin labeling and diffusion-weighted MR imaging: Utility in differentiating idiopathic orbital inflammatory pseudotumor from orbital lymphoma.

PURPOSE: To assess arterial spin-labeling (ASL) and diffusion-weighted imaging (DWI) and in combination for differentiating between idiopathic orbital inflammatory pseudotumor (IOIP) and orbital lymphoma. MATERIAL AND METHODS: A retrospective study was done on 37 untreated patients with orbital masses, suspected to be IOIP or orbital lymphoma that underwent ASL and DWI of the orbit. Quantitative measurement of tumor blood flow (TBF) and apparent diffusion coefficient (ADC) of the orbital lesion was done. RESULTS: There was a significant difference (P = 0.001) in TBF between patients with IOIP (n = 21) (38.1 ± 6.2, 40.3 ± 7.1 ml/100 g/min) and orbital lymphoma (n = 16) (55.5 ± 7.1, 56.8 ± 7.9 ml/100 g/min) for both observers respectively. Thresholds of TBF used for differentiating IOIP from orbital lymphoma were 48, 46 ml/100 g/min revealed area under the curve (AUC) of (0.958 and 0.921), and accuracy of (86% and 83%) for both observers respectively. There was a significant difference (P = 0.001) in ADC between patients with IOIP (1.04 ± 0.19, 1.12 ± 0.23 × 10-3 mm2/s) and orbital lymphoma (0.69 ± 0.10, 0.72 ± 0.11 × 10-3 mm2/s) for both observers respectively. Thresholds of ADC used for differentiating IOIP from orbital lymphoma were 0.84 and 0.86 × 10-3 mm2/s with AUC of (0.933 and 0.920), and accuracy of 89% and 90% for both observers respectively. The combined TBF and ADC used for differentiating IOIP from orbital lymphoma had AUC of (0.973 and 0.970) and accuracy of (91% and 89%) for both observers respectively. CONCLUSION: TBF and ADC alone and in combination are useful for differentiating IOIP from orbital lymphoma.