ABSTRACT
Objective:To investigate the value of conventional MRI and high resolution diffusion weighted imaging (DWI) for preoperative discrimination between nasopharyngeal-skull base osteomyelitis (NP-SBO) and locoregionally advanced nasopharyngeal carcinoma (LA-NPC).Methods:From January 2017 to October 2021, 27 patients of NP-SBO and 32 patients of LA-NPC were retrospectively analyzed at the Eye & ENT Hospital of Fudan University. The clinical characteristics and conventional MRI features were collected, and the apparent diffusion coefficient (ADC) values of polygonal (ADC polygonal) and small circle were measured from readout segmentation of long variable echo-trains (RESOLVE) DWI. MRI features included laterality, margin, signal intensity of T 1WI and T 2WI, enhancement degree, component, abscess, deep mucosal white line, bone invasion, lymph nodes involvement and other accompany symphtoms. The independent sample t test, χ 2 test or Fisher exact test were used to compare the features and ADC values of the NP-SBO and LA-NPC groups. The logistic regression was applied to select independent predictors in the distinguishing LA-NPC from NP-SBO. Then, the conventional MRI model, ADC model and conventional MRI in combination with ADC model were built. The area under the receiver operating characteristic curve (AUC) of models were compared using DeLong test. Results:The age, diabetic status, cranial nerve deficits, inner component, abscess, deep mucosal white line, lymph nodes involvement and ADC polygonal were significantly different between NP-SBO and LA-NPC groups ( P<0.05). The logistic regression analysis showed that ADC polygonal (OR=0.972, 95%CI 0.951-0.993, P=0.011) and abscess (OR=0.101, 95%CI 0.013-0.774, P=0.027) were the independent predictors in the discrimination of NP-SBO and LA-NPC. The AUC (95%CI) of conventional MRI model (abscess), ADC model (ADC polygonal) and combination model were 0.634 (0.499-0.756), 0.870 (0.757-0.943), and 0.925(0.829-0.979), respectively. The AUC of combination model was higher than that of conventional MRI model ( Z=4.77, P<0.001), while there was no difference between combination model and ADC model ( Z=1.87, P=0.062). The AUC of conventional MRI model was lower than that of ADC model ( Z=2.84, P=0.005). Conclusion:Conventional MRI in combination with RESOLVE DWI shows good performance in differentiating between NP-SBO and LA-NPC, especially for abscess in combination with ADC polygonal value.
ABSTRACT
Objective:To explore CT and MRI features of the endolymphatic sac tumor (ELST).Methods:The CT and MRI morphology confirmed by surgical pathology for 19 patients with ELST were retrospectively analyzed from June 2011 to May 2019 in Eye & ENT Hospital of Fudan University. The features of CT and MRI included location, size, adjacent structures invasion, CT values, bone destruction, features of T 1WI and T 2WI, enhancement distribution characteristics, dynamic enhancement curve morphology, DWI signal characteristics. The ADC values of the lesions and ipsilateral medial pterygoid muscles were compared using a paired t test. Results:Nineteen ELST patients (one with bilateral diseases) were included. Totally 20 ears (right 9 and left 11) of 13 females and 6 males were studied. The masses with slightly high-density and obscure boundary were located around the vestibular aqueduct at the posterior edge of the petrosal bone. Bone destruction involved mastoid process of the middle ear (16 ears), jugular foramen (11 ears), semicircular canal (10 ears), facial nerve canal (7 ears) and internal auditory canal (9 ears). A large amount of residual bone could be found in the interior of nineteen masses. The CT value was (78.6±21.9) HU. The lesion showed central iso-intensity and peripheral hyperintensity on T 1WI and T 2WI in 16 ears, while no obvious hyperintensity on T 1WI in the other 4 ears. The hyperintensity on T 1WI was around the margin of the lesion in 10 ears, situated at lateral side in 5 ears and all over the lesion in 1 ear. Flow voids signals could be seen in 9 ears as well. Liquid-liquid plane was seen on T 2WI in 2 ears. The solid mass portion which showed iso-intensity on both T 1WI and T 2WI presented marked enhancement on contrast-enhanced T 1WI, while other part of the mass no enhancement. DWI of 14 ears illustrates no evidence of restricted diffusion, and the ADC value [(1.25±0.08)×10 -3 mm 2/s] was slightly higher than that of the medial pterygoid muscles ( t=4.437, P=0.001). The style of time-signal intensity curves of the dynamic contrast-enhanced MRI was rapidly ascending followed by descending curves in 2 ears. Conclusion:Imaging findings of ELST have some characteristics, including located around the vestibular aqueduct at the posterior edge of the petrosal bone, bone destruction, peripheral hyperintensity on T 1WI and no restricted diffusion, which is helpful for its diagnosis.