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Objective:To investigate the value of low-energy virtual monoenergetic image (VMI) at 45 keV in visualizing the primary tumor and T staging of hypopharyngeal squamous cell carcinoma.Methods:The clinical and imaging data of 58 patients with hypopharyngeal squamous cell carcinoma from April 2018 to January 2020 at Eye & ENT Hospital, Fudan University were analyzed retrospectively. All the patients underwent a venous phase contrast-enhanced dual-source dual-energy CT scan before treatment. The VMI at 45 keV and standard linearly blended image (30% 80 kV+70% 140 kV) were acquired from dual-energy post-processing software. One senior radiologist and one junior radiologist independently assessed the visibility of the tumor on the 45 keV VMI and standard linearly blended image using a 5-point Likert rating scale. Furthermore, the senior radiologist assessed the visibility of the tumor at each subsite (piriform fossa, posterior pharyngeal wall, postcricoid region) and determined the invasion depth of the tumor (extension to esophagus, invasion to strip muscles and prevertebral muscles) and performed the T staging of the primary tumor using the two sets of images blindly. The accuracy of T staging was calculated, using pathological T staging (surgical cases) or clinical T staging (non-surgical cases) as the gold standard. The image scores of the two sets of images were compared using Wilcoxon rank sum test. McNemar-Bowker test was used to compare the accuracy of T staging using the two sets of images.Results:The overall image scores of the 45 keV VMI and standard linearly blended image from the senior radiologist were 3.5 (3, 4) and 3 (2, 3) respectively ( Z=-7.03, P<0.001), and the scores from the junior radiologist were 3 (3, 4) and 2 (2, 3) ( Z=-6.93, P<0.001). The scores of the 45 keV VMI were significantly higher than those of the standard linearly blended image in visualizing tumors in the piriform fossa, posterior pharyngeal wall, and postcricoid region, as well as in detecting invasion to the strip muscles ( P<0.05). There was no significant difference in the scores of the two sets of images in determining whether the tumor extended to esophagus or invaded prevertebral muscles ( P>0.05). Referring to pathological and clinical T stage, the accuracy of T staging determined by the 45 keV VMI and standard linearly blended image was 87.9% (51/58) and 81.0% (47/58) respectively, and the difference was not significant (χ 2=3.33, P=0.189). Conclusions:The 45 keV VMI is superior to the standard linearly blended image in visualizing tumors and detecting invasion to the strip muscles of hypopharynx squamous cell carcinoma. However, the accuracy of determining T staging using 45 keV VMI is slightly improved than that of standard linearly blended image, and the difference is not statistically significant. In determining whether the tumor extends to esophagus or invades prevertebral muscles, 45 keV VMI shows no significant advantage over standard linearly blended image.
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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.
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<p><b>OBJECTIVE</b>To evaluate the value of HRCT with multi-planar reformation (MPR) in the diagnosis of otosclerosis.</p><p><b>METHODS</b>138 ears in 129 patients with otosclerosis confirmed by surgery were evaluated retrospectively, using the MPR image along stapes as standard image, and 132 normal ears were collected as the control group.</p><p><b>RESULTS</b>In the otosclerosis group, HRCT-MPR was positive in 108 ears, suspicious positive in 12 ears, and negative in 18 ears.In the control group, HRCT-MPR was positive in 4 ears, suspicious positive in 9 ears, and negative in 119 ears. The sensitivity for HRCT-MPR was 87.0% and the specificity was 90.2%. However, with 2 mm axial CT alone, the sensitivity was only 47.8%.The positive findings were mainly fenestral foci which related to stapes.</p><p><b>CONCLUSIONS</b>HRCT-MPR showed high rate of sensitivity and specificity.We recommend the MPR image along stapes as standard image for otosclerosis diagnosis.</p>