Effect of Matrix Size and Acquisition Mode on Image Quality and Radiation Dose of Ultra-High-Resolution CT of the Temporal Bone: An Anatomical Study.

Purpose: To compare image quality and radiation exposure between super- and ultra-high-resolution helical and super-high-resolution volumetric CT of the temporal bone. Methods: Six cadaveric temporal bone specimens were used to evaluate key temporal bone structures using the following CT reconstruction and acquisition modes: helical and single-volume acquisition modes in super-high resolution (0.25-mm slice thickness, 10242 matrix), and helical mode in ultra-high resolution (0.25-mm slice thickness, 20482 matrix). Two observers performed 5 previously described preoperative measurements, measured noise and signal-to-noise ratios for air, and noise for bone, and rated the visualization of 5 anatomical structures on a 4-point scale, for each reconstruction mode. Radiation dose exposure was recorded for each examination. Results: There was no significant difference between any of the quantitative or qualitative measurements in any of the reconstruction and acquisition modes. There was a slight increase in noise and a decrease in signal-to-noise ratio in the air using the single-volume mode (115 ± 13.1 HU and 8.37 ± 0.91, respectively) compared to the helicoidal super-high-resolution (92.4 ± 11.8 HU and 10.8 ± 1.26, respectively) and helicoidal ultra-high-resolution (91.1 ± 10.7 HU and 10.9 ± 1.39, respectively) modes (P < .002). The volumic CT dose index was 50.9 mGy with helical acquisition and 29.8 mGy with single-volume acquisition mode (P < .0001). Conclusion: The single-volume super-high-resolution acquisition mode allows a reduction in radiation dose exposure without compromising image quality compared to helical scanning, but with a slightly lower signal-to-noise ratio in air with the single-volume mode, while there was no difference in image quality between the helical super- and ultra-high-resolution modes.

Optimized 3D-FLAIR sequences to shorten the delay between intravenous administration of gadolinium and MRI acquisition in patients with Menière's disease.

OBJECTIVES: The aim of this study was to shorten the 4-h delay between the intravenous administration of gadolinium and MRI acquisition for hydrops evaluation using an optimized 3D-FLAIR sequence in patients with Menière's disease. METHODS: This was a single-center prospective study including 29 patients (58 ears), recruited between November 2020 and February 2021. All patients underwent a 3-T MRI with an optimized 3D-FLAIR sequence without contrast then at 1 h, 2 h, and 4 h after intravenous administration of gadobutrol. The signal intensity ratio was quantitatively assessed with the region of interest method. We also evaluated the volume of endolymphatic structures (saccule, utricle) then the presence of endolymphatic hydrops and blood-labyrinthine barrier impairment at each acquisition time. RESULTS: For all ears, the signal intensity ratio was significantly non-inferior at 2 h compared to 4 h, with a mean geometric signal intensity ratio at 0.83 (95% CI: 0.76 to 0.90, one-sided p < .001 for non-inferiority at -30% margin). Mean volume equivalence of saccule and utricle between 2 and 4 h was proven at a ± 0.20 standardized deviation equivalence margin. Intra-rater agreements (Cohen's kappa) were all greater than 0.90 for all endolymphatic hydrops location and blood-labyrinthine-barrier impairment between the 2- and 4-h assessments. CONCLUSIONS: We demonstrated that using an optimized 3D-FLAIR sequence we could shorten the acquisition from 4 to 2 h with a high reliability for the diagnosis of endolymphatic hydrops and blood-labyrinthine-barrier impairment. CLINICAL TRIAL REGISTRATION: Clinical trial no: 38RC15.173 KEY POINTS: • Magnetic resonance imaging with delayed 3D-FLAIR sequences allows the diagnosis of endolymphatic hydrops in patients with definite Menière's disease. • An optimized 3D-FLAIR sequence with a long TR of 16000 ms and a constant flip angle allows for reducing the delay between intravenous injection of gadobutrol and MRI acquisition from 4 to 2 h to diagnose endolymphatic hydrops. • Reducing this delay between intravenous injection and MRI acquisition could have implications for clinical practice for both patients and imaging departments.

Endovascular treatment of infectious intracranial aneurysms complicating infective endocarditis: a series of 31 patients with 55 aneurysms.

PURPOSE: Endovascular treatment (EVT) has become a major option in management of infectious intracranial aneurysms (IIAs) complicating infective endocarditis. We report a retrospective, single-center series of consecutive patients with IIAs treated by EVT. METHODS: Patients were included from January 2009 to July 2020. IIAs were diagnosed on DSA. Each patient underwent a neurological assessment before and after EVT and was followed up by imaging within 15 days of EVT. Safety was assessed on the evolution of NIHSS score. A minor stroke was defined as a worsening of NIHSS < 4 points. Efficacy was defined as the absence of hemorrhagic event during cardiac surgery and the exclusion of the IIA on control imaging. RESULTS: Sixty-two IIAs (30 ruptured) were diagnosed in 31 patients. Fifty-six IIAs were diagnosed on the first DSA and 6 on the early control exploration. EVT was achieved in 55 IIAs by parent artery occlusion with glue in 52 distal IIAs and coils in 3 proximal IIAs. IIAs were located in 90.9% of cases on a fourth-division branch of a cerebral artery. The neurological examination remained unchanged in 29 patients (93.5%), and 2 patients suffered minor stroke. EVT was performed before cardiac surgery in 20/22 patients. All treated IIAs were excluded on follow-up imaging. No hemorrhage was observed during cardiac surgery or in the aftermath. Seven (11.3%) unruptured IIAs were not embolized. CONCLUSION: EVT of IIAs by occlusion of the parent artery is effective in preventing rupture and carries no significant neurological risk.

Recurrent vestibulopathy: are cVEMP, oVEMP and inner ear MRI useful to distinguish patients with Menière's disease and vestibular migraine?

PURPOSE: The aim of this study was to assess the rate of endolymphatic hydrops (EH) on MRI and the rate of otolithic dysfunction with cVEMP and oVEMP, in patients with recurrent vertigo such as Menière's disease (MD), vestibular migraine (VM) and vestibular Menière's disease (vMD). METHODS: In this retrospective study, we performed 3D-FLAIR sequences with delayed acquisition in 20 MD, 20 VM and 20 vMD patients. Each subject was then assessed for the presence of EH on MRI. All patients underwent pure-tone audiometry, cVEMP and oVEMP. RESULTS: In MD patients, EH was observed in 18 (90%) out of 20 patients while EH was observed in only 1 MV (5%) and 1 vMD (5%) patients. We found significant differences between groups for the presence of EH on MRI (p = 0.001). MD patients had significant higher PTA level (p < 0.001) and oVEMP impairment than MV and vMD (p = 0.08 and p = 0.06, respectively). However, no significant differences were observed for cVEMP impairment, either asymmetric ratio (p = 0.36) and 1000/500 ratio (p = 0.20). CONCLUSIONS: Concerning cVEMP, we observed no significant differences between VM, vMD and MD. However, we observed higher oVEMP impairment, PTA level and EH on MRI in MD patients. We believe that MRI could be used to differentiate MD from VM patients with cochlear symptoms. However, in cases of migraine associated with recurrent vertigo and without cochlear symptoms, we believe that MRI is not a useful tool to differentiate between VM and vMD.

Functional treatment of temporal bone chondroblastoma: retrospective analysis of 3 cases.

PURPOSE: To describe and analyse functional treatment of temporal bone chondroblastoma (TBCh). METHODS: From January 2000 to June 2019, at the Department of Otorhinolaryngology, Hôpital Lariboisière, Paris, France, patients with TBCh were enrolled in this study. All cases routinely performed pre-operatory work-up including evaluation of performance status, audio-vestibular function test, ear endoscopy, contrasted CT scan and MRI of head and neck region; in one case we also performed an angio-CT scan. All patients underwent resection of the tumour with a "functional" approach RESULTS: Three male patients (mean age 46,6 years)-two primary tumours and one recurrence-were treated. In all three cases the tumour invaded the middle ear with a variable degree of hearing loss and infiltration of temporal bone structures. All surgeries were performed with a microscopic approach associated with open/endoscopic approach when necessary. Inner ear and facial nerve were speared in all cases and the TMJ was partially resected in 2 cases due to its moderate involvement. At present, after a mean follow-up of 103 months (range 40-225 months), only one case presented recurrence which has been successfully treated with radiotherapy. CONCLUSIONS: Our results of treatment suggest that functional surgery can be relevant in the management of TBCh since it is focused on both treatment of this pathology and maintenance of a good quality of life.

MRI contribution for the detection of endolymphatic hydrops in patients with superior canal dehiscence syndrome.

PURPOSE: Patients with superior semicircular canal dehiscence syndrome, which can only be treated by surgery, present cochleo-vestibular symptoms related to a third-mobile window but also endolymphatic hydrops. Since cVEMP and oVEMP are disturbed by the presence of the dehiscence, the aim of the study is to assess the value of MRI for the diagnosis of endolymphatic hydrops in patients with superior semicircular canal dehiscence syndrome in comparison with cVEMP and oVEMP. METHODS: In this retrospective cohort study we enrolled 33 ears in 24 patients with superior semicircular dehiscence syndrome who underwent a 4-h delayed intravenous Gd-enhanced 3D-FLAIR MRI and pure tone audiometry, cVEMP and oVEMP. For each patient MRI images were evaluated by two radiologists who used a compartmental endolymphatic hydrops grading system in comparison with cVEMP and oVEMP. RESULTS: Endolymphatic hydrops was found on MRI in 9 out of 33 SCDS ears (27.3%). We found no significant correlation between the presence of endolymphatic hydrops on MRI and cVEMP and oVEMP (p = 0.36 and p = 0.7, respectively). However, there was a significant correlation between the presence of endolymphatic hydrops on MRI and the degree of sensorineural hearing loss, Air Conduction-Pure Tone Average level (p = 0.012) and Bone Conduction-Pure Tone Average level (p = 0.09), respectively. CONCLUSION: We demonstrated that EH might be observed in 27.3% of superior semicircular dehiscence syndrome ears. The role of inner ear MRI is important to detect endolymphatic hydrops, since cVEMP and oVEMP are disturbed by the presence of the dehiscence, because these patients could benefit from a medical treatment. LEVEL OF EVIDENCE: Level 3.

MRI diagnosis of saccular hydrops: Comparison of heavily-T2 FIESTA-C and 3D-FLAIR sequences with delayed acquisition.

PURPOSE: Currently, 3D-FLAIR sequence performed 4hours after the intravenous administration of a single dose of contrast media is the imaging technique of choice for the diagnosis of saccular hydrops (SH). Recently, the diagnosis of SH has also been reported with heavily-T2 weighted sequences. MATERIALS AND METHODS: In this retrospective imaging study, we performed 3D-FLAIR sequences 4hours after contrast media administration and 3D FIESTA-C sequences before and 4hours after contrast media administration in 30 patients with unilateral definite, probable or possible clinical diagnosis of Menière's disease (MD). Two radiologists, blinded to the clinical data, independently assessed the presence of saccular hydrops. Inter-reader agreement tests were performed. RESULTS: On delayed post-contrast 3D-FLAIR sequence, 15 patients out of 30 referred with a SH that was never seen on the controlateral asymptomatic side. The specificity and the sensitivity to detect MD side were 100% and 50% respectively. On non-enhanced 3D FIESTA-C sequence, 16 patients out of 30 (53%) referred with a saccular hydrops that was observed in 6 patients on the clinical asymptomatic ear. The specificity and the sensitivity to detect MD side were 80% and 33% respectively. On delayed 3D FIESTA-C sequence, 13 patients out of 30 (43%) referred with a saccular hydrops that was seen in 4 patients on the controlateral asymptomatic side. The specificity and the sensitivity to detect MD side were 83% and 27% respectively. CONCLUSION: Delayed post-contrast 3D-FLAIR is highly specific of MD symptoms while 3D FIESTA-C sequences are less sensitive and specific for the diagnosis of SH.

The vestibular aqueduct ossification on temporal bone CT: an old sign revisited to rule out the presence of endolymphatic hydrops in Menière's disease patients.

OBJECTIVES: Menière's disease (MD) is associated with endolymphatic hydrops (EH), which is an accumulation of excessive endolymphatic fluid in the inner ear. However, using temporal bone CT, lower visualization rates of the vestibular aqueduct (VA) in these patients have also been reported. METHODS: In this retrospective single-center imaging study, we have included 25 healthy subjects and 47 patients having a definite, probable, or possible clinical diagnosis of MD that underwent temporal bone CT and inner ear MRI performed 4 h after contrast media administration. Two radiologists independently ranked the morphology of the VA in healthy subjects and in MD patients, using a three-level score (completely visible, discontinuous, and not visible). Each subject was then graded, based on both the VA's appearance and on EH presence. RESULTS: In healthy subjects, the VA was normal (grade 0) in 22/25 (88%) ears and discontinuous (grade I) in 3 healthy ears (12%). In the symptomatic ears of MD patients, we found 17/56 ears (30.3%) with VA grade 0, 15/56 ears (26.8%) with grade I, and 24/56 ears (42.8%) with grade II (p < 0.001). In MD patients, EH was observed in 46/94 ears (48.9%). A VA of grade 0 would eliminate the presence of EH with a negative predictive value of 88.6%, while a VA grade II would predict the presence of saccular hydrops with a positive predictive value of 93.1%. CONCLUSION: The evaluation by temporal bone CT of the VA can predict the presence of EH on MRI with a high positive predictive value. KEY POINTS: • The evaluation by temporal bone CT of the vestibular aqueduct can predict the presence of EH on MRI. • A vestibular aqueduct of grade 0 would eliminate the presence of EH on MRI with a negative predictive value of 88.6%. • A vestibular aqueduct grade II would predict the presence of endolymphatic hydrops on MRI with a positive predictive value of 93.1%.

Endolymphatic Hydrops Secondary to Spontaneous Intracranial Hypotension.

BACKGROUND: Spontaneous intracranial hypotension may be associated with neuro-otological symptoms that might mimic Menière's disease. CASE PRESENTATION: We report the case of a 53-year-old male presenting bi-frontal headache with recurrent spells of vertigo, left fluctuating hearing loss, and tinnitus. Dedicated brain and inner ear Magnetic Resonance Imaging, including a post-contrast 4 hours delayed FLAIR sequence, revealed typical signs of spontaneous intracranial hypotension associated with endolymphatic hydrops involving the left saccule and cochlea. CONCLUSIONS: Audio vestibular manifestations mimicking Menière's disease in spontaneous intracranial hypotension could be explained by endolymphatic hydrops, which can be detected using dedicated magnetic resonance imaging sequences.

High frequency of ophthalmic origin of the middle meningeal artery in chronic subdural hematoma.

PURPOSE: Embolization of middle meningeal artery (MMA) has been proposed for postoperative recurrences and primary treatment of chronic subdural hematoma (CSDH). This endovascular intervention is safe only when MMA originates from the internal maxillary artery. The aim of this study was to report an unusual high frequency of MMA originating from the ophthalmic artery, which prohibits this treatment. METHODS: In this retrospective study, we reviewed the anatomical origin of the MMA in patients with CSDH who were referred to our center for endovascular treatment between January 2017 and May 2019 (42 patients with 58 CSDH). We compared the prevalence of this variant in a control group of 66 patients who underwent embolization for epistaxis during the same period. RESULTS: In CSDH group, MMA originated from the ophthalmic artery in 8 out of 58 internal carotid arteries (13.8%). In the control group, this variant was observed in only 1 case out of 131 internal carotid arteries (0.7%) (OR = 20; 95% CI 2.6 to 925.2, p = 0.0003). CONCLUSION: In this study, we report an extremely high prevalence of MMA originating from the ophthalmic artery in CSDH. In the hypothesis of prospective studies, a priori recognition of this variant will be necessary in order to exclude patients in whom endovascular treatment will not be feasible.

Isolated enhancement of the superior semi-circular canal on inner ear MRI: acute vestibular syndrome or superior semi-circular canal dehiscence?

PURPOSE: Recently, it has been reported that patients with acute vestibular syndrome (AVS) could present a marked enhancement of the semi-circular canals, involving mostly the superior semi-circular canals on delayed inner ear MRI. METHODS: We reported one patient having AVS and another one having superior semi-circular canal dehiscence syndrome (SCDS) who underwent delayed inner ear MRI performed 4 h after contrast media administration. RESULTS: On delayed inner ear MRI, a marked enhancement of the superior semi-circular canal was observed in both patients. Although the clinical presentation is clearly not the same, the co-existence between these two disorders is possible. For this reason, in patients with AVS, the presence of a marked enhancement of the superior semi-circular canal should rule out the presence of a co-existing SCDS on temporal bone CT, particularly if the patient reported cochlear symptoms such as pulsatile tinnitus and/or autophony. CONCLUSION: To our knowledge, this is the first report showing this finding on delayed inner ear MRI in a patient with SCDS. In AVS patients, this radiological anomaly could be particularly disturbing and should rule out the presence of a co-existing SCDS.

Electrophysiological and inner ear MRI findings in patients with bilateral vestibulopathy.

PURPOSE: Bilateral vestibulopathy (BV) is an uncommon disorder and the etiology remained idiopathic in most cases. Delayed 3D-FLAIR sequences have provided new insights into various inner ear diseases, allowing the evaluation of the endolymphatic space and the permeability of the blood-labyrinthine barrier (BLB). The aim of this study was to assess both the morphology of the endolymphatic space and the permeability of the BLB in patients with BV as evaluated by delayed 3D-FLAIR sequences. METHODS: In this retrospective study, we performed 3D-FLAIR sequences 4 h after administering contrast media to 42 patients with BV. Two radiologists independently evaluated the morphology of the endolymphatic space (either vestibular atelectasis or endolymphatic hydrops) and the permeability of the BLB. RESULTS: Morphologic anomalies of the endolymphatic space and vestibular blood-labyrinthine barrier impairment were observed in 59.6% of patients with BV. Bilateral vestibular atelectasis (VA) was found in 21 patients (50%), involving only the utricle and all three ampullas while the saccule was always observed with no sign of collapse: idiopathic BV (n = 19), aminoglycoside administration (n = 1) and few days following abdominal surgery (n = 1). One patient had bilateral vestibular malformation. BLB impairment was observed in five patients (11.9%): paraneoplastic (n = 1), lymphoma (n = 1), autoimmune (n = 1), and vestibular "neuritis" (n = 2). Seventeen patients (40.4%) had normal MRI with no endolymphatic space anomaly or BLB impairment. CONCLUSION: Patients with BV presented with morphologic anomalies of the endolymphatic space or BLB impairment in 59.6% of patients.

The vestibular aqueduct sign: Magnetic resonance imaging can detect abnormalities in both ears of patients with unilateral Meniere's disease.

BACKGROUND AND PURPOSE: In patients with Meniere's disease (MD), saccular hydrops can only be studied by magnetic resonance imaging (MRI) at a late stage when the disease is already responsible for moderate to severe hearing loss. However, these patients may also present vestibular aqueduct (VA) abnormalities. MATERIALS AND METHODS: In this prospective study (38RC14.428 for healthy subjects/38RC15.173 for patients), imaging was carried out on a 3T MRI scanner. Twenty healthy subjects (13 women, median age 53.5 [52.2-66.7]) and twenty MD patients (9 women, median age 54.5 [52-66.7]) had MRI scans with 3D-FLAIR sequences without injection, then 4 hours after a single intra-venous dose of contrast agent. Two radiologists independently ranked the morphology of the VA in the healthy subjects and in MD patients, using a three-level score (completely visible, discontinuous and not visible). Each subject was then graded, based on both the VA's appearance and on saccular hydrops presence. Inter-reader agreement tests were performed. RESULTS: In controls and patients, VA modifications were symmetrical without significant difference between the symptomatic and asymptomatic ears. The presence of at least one ear with discontinuous VA showed a correlation with clinical MD (P < 0.001) with a sensitivity of 90%. Ten patients had saccular hydrops, but only in the symptomatic ears. The evaluation of VA did not differ between MRI, both within MRI series or between the two radiologists (kappa without and with contrast agent = 0.9 and 0.92 respectively). CONCLUSION: Analysis of the vestibular aqueduct by MRI detects abnormalities in both ears of patients with unilateral MD.

Detection of intralabyrinthine abnormalities using post-contrast delayed 3D-FLAIR MRI sequences in patients with acute vestibular syndrome.

PURPOSE: 3D-FLAIR sequences with delayed acquisition after contrast medium injection have demonstrated new insights into blood-labyrinthine barrier (BLB) abnormalities in various diseases. The aim of this study was to assess the BLB in patients referred with unilateral acute vestibular syndrome (UAVS). MATERIALS AND METHODS: In this retrospective multicenter imaging study, we performed 3D-FLAIR and steady-state free precession (SSFP) sequences 4 h after contrast medium administration in 26 healthy volunteers and in 30 patients with UAVS. Two radiologists, blinded to the clinical data, independently assessed the asymmetrical enhancement of the labyrinthine structures and the vestibular nerve on 3D-FLAIR sequences, and the signal of the labyrinthine structures on SSFP sequences. Inter-reader agreement tests were performed. RESULTS: An asymmetrical enhancement of the semicircular canals was observed in 26 out of 30 ears (86.6%, p < 0.001) and never observed in healthy subjects. An asymmetrical enhancement of the vestibular nerve was never observed in either patients or healthy subjects. An asymmetrical enhancement of the cochlea was observed on the 3D-FLAIR sequence in 6 out of 30 ears only in the patients' group (20%, p = 0.03) and always associated with an enhancement of at least one semicircular canal. A low signal on SSFP sequences was observed only in 11 out of 30 symptomatic ears (36.7%, p < 0.001), involving the utricle in 7 ears and the superior semicircular canal in 4 ears. CONCLUSION: Patients with typical UAVS presented with semicircular canal enhancement on MRI, while an asymmetrical enhancement of the vestibular nerve was not displayed. TRIAL REGISTRATION: NCT02529475 KEY POINTS: • Patients with typical vestibular neuronitis presented with semicircular canal enhancement on MRI in 87% of cases. • An enhancement of the vestibular nerve was never displayed.

In vivo imaging of saccular hydrops in humans reflects sensorineural hearing loss rather than Meniere's disease symptoms.

OBJECTIVES: A case-controlled imaging study demonstrated that saccular hydrops was specific to Meniere's disease (MD), but only present in a subset of patients. Here, we compared patients with definite MD, vertigo and sensorineural hearing loss (SNHL) to elucidate the relationship between saccular hydrops and extent of SNHL. METHODS: In this prospective study, we performed 3D-FLAIR sequences between 4.5 and 5.5 h after contrast media injection in patients with MD (n=20), SNHL (n=20), vertigo (n=20) and 30 healthy subjects. Two radiologists independently graded saccular hydrops. ROC analysis was performed to determine the hearing loss threshold to differentiate patients with saccular hydrops. RESULTS: Saccular hydrops was found in 11 of 20 MD patients, 10 of 20 SNHL patients and in none of the vertigo patients and healthy subjects. In SNHL patients, 45 dB was the threshold above which there was a significant association with saccular hydrops, with sensitivity of 100 % and specificity of 90 %. In MD patients, 40 dB was the threshold above which there was a significant association with saccular hydrops, with sensitivity of 100 % and specificity of 44 %. CONCLUSIONS: Our results indicate saccular hydrops as a feature of worse than moderate SNHL rather than MD itself. KEY POINTS: • MRI helps clinicians to assess patients with isolated low-tone sensorineural hearing loss. • Saccular hydrops correlates with sensorineural hearing loss at levels above 40 dB. • Vertigo patients without sensorineural hearing loss do not have saccular hydrops. • Saccular hydrops is described in patients without clinical diagnosis of Meniere's disease.

MRI of endolymphatic hydrops in patients with Meniere's disease: a case-controlled study with a simplified classification based on saccular morphology.

OBJECTIVES: Endolymphatic hydrops (EH) can be studied in patients by MRI. With the semi-quantitative grading system, previous imaging studies showed discrepancies in the occurrence and grading of EH in patients with Meniere's disease (MD). Here, we compared the inversion of the saccule to utricle area ratio (SURI) with the semi-quantitative method of grading conventionally used to diagnose MD. METHODS: Imaging was carried out on a 3-T MRI scanner. We performed 3D-FLAIR sequences 4 h after a single intravenous dose of contrast agent. Two radiologists independently studied the morphology of the inner ear structures in the healthy subjects and MD patients. Each subject was then graded on the basis of the EH semi-quantitative analysis and on saccular morphology using axial and sagittal reference slices in the vestibule plane. RESULTS: Thirty healthy subjects and 30 MD patients had MRI scans. Using the semi-quantitative method, we found no significant difference in the number of subjects with EH between the two groups. SURI was found in 15 out of 30 MD patients and in none of the 30 healthy subjects. In three MD patients the saccule was not visible. CONCLUSION: SURI is currently the most specific criterion for imaging diagnosis of MD. KEY POINTS: • Half of MD patients presented with inversion of the saccule to utricle ratio. • Saccular analysis is crucial when assessing patients with Meniere's disease. • In some patients, the saccule is not visible, suggestive of intra-labyrinthine fistulae.

Influence of inversion time on endolymphatic hydrops evaluation in 3D-FLAIR imaging.

The MRI evaluation of endolymphatic hydrops currently relies on inversion recovery sequences. Signal intensity of such sequences depends on the Inversion Time (TI) parameter. Here, we assessed endolymphatic compartment variation with two 3D-FLAIR sequences, closely similar except for the TI (2300 and 2400ms), in healthy volunteers and patients. We found that the semi-quantitative method of grading was highly dependent on the TI, contrasting with the recently proposed saccular-based grading of endolymphatic hydrops.

Ultra-high-resolution CT of the temporal bone: The end of stapes prosthesis dimensional error and correlation with patient symptoms.

PURPOSE: To describe the reliability of ultra-high-resolution computed tomography (UHR-CT) in the measurement of titanium stapes prostheses using manufacturer data as a reference. MATERIALS AND METHODS: This retrospective study included patients treated by stapedectomy with titanium prostheses who underwent UHR-CT between January 2020 and October 2023. Images were acquired using an ultra-high-resolution mode (slice thickness: 0.25 mm; matrix, 1024 × 1024). Two radiologists independently evaluated the length, diameter, and intra-vestibular protrusion of the prosthesis. Post-operative air-bone gaps (ABGs) were recorded. RESULTS: Fourteen patients were enrolled (mean age, 44.3 ± 13.8 [SD] years, 9 females), resulting in 16 temporal bone UHR-CTs. The exact length was obtained in 81.3 % (n = 13/16) and underestimated by 0.1 to 0.3 mm in the remaining 18.7 % (n = 3/16) CT scans for both readers (mean misestimation: -0.02 ± 0.06 [SD] mm, overall underestimation of 0.43 %). The exact diameter was reported in 75 % (n = 12/16) and 87.5 % (n = 14/16) of the CT scans for readers 1 and 2, respectively, and was off by 0.1 mm in all discrepancies (mean misestimation: 0.01 ± 0.04 [SD] mm, overall overestimation of 2.43 %). Intravestibular prosthesis protrusion was of 0.5 ± 0.43 [SD] mm (range: 0-1) and 0.49 ± 0.44 [SD] mm (range: 0-1.1) for readers 1 and 2, respectively, and did not correlate with ABGs (r = 0.25 and 0.22; P = 0.39 and 0.47 for readers 1 and 2, respectively). Intra and interobserver agreements were excellent. CONCLUSION: UHR-CT provides 99.6 % and 97.6 % accuracy for prosthesis length and diameter measurements, respectively.

Measurement of stapes footplate thickness using ultra-high-resolution computed tomography: stapes axial plane correlates better with otosclerosis than lateral semicircular canal plane.

BACKGROUND, AIMS: Stapes footplate thickness measurement using ultra-high-resolution CT has been described only in the lateral semicircular canal plane. The purpose of this study was to compare stapes footplate thickness between the lateral semicircular canal and stapes axial planes in patients with otosclerosis compared to controls. MATERIAL AND METHODS: We performed a retrospective single-center study of patients undergoing high-resolution temporal bone CT. Two radiologists measured stapes footplate thickness in both the lateral semicircular canal and stapes axial planes. RESULTS: Between February 2020 and October 2022, we collected 81 ears from 49 patients (75% of women; mean age 51.22 ± 16.6 years, 17 otosclerosis, and 64 controls). In the stapes axial plane, there was a significant anterior thickening in otosclerosis patients (Reader 1: 0.52 ± 0.12 [0.3-0.7] vs. 0.41 ± 0.08 [0.3-0.6], p = 0.001; Reader 2: 0.54 ± 0.06 [0.5-0.7] vs. 0.39 ± 0.08 [0.2-0.6], P < 0.001) compared to controls. These differences were not significant using the lateral semicircular canal plane. CONCLUSION: The stapes footplate was thickened at its AC in otosclerosis patients using only the stapes axial plane. SIGNIFICANCE: We propose to use the stapes axial plane instead of the lateral semicircular canal plane when analyzing the stapes.

Ultra-high-resolution CT of the temporal bone: Comparison between deep learning reconstruction and hybrid and model-based iterative reconstruction.

PURPOSE: The purpose of this study was to evaluate the ability of ultra-high-resolution computed tomography (UHR-CT) to assess stapes and chorda tympani nerve anatomy using a deep learning (DLR), a model-based, and a hybrid iterative reconstruction algorithm compared to simulated conventional CT. MATERIALS AND METHODS: CT acquisitions were performed with a Mercury 4.0 phantom. Images were acquired with a 1024 × 1024 matrix and a 0.25 mm slice thickness and reconstructed using DLR, model-based, and hybrid iterative reconstruction algorithms. To simulate conventional CT, images were also reconstructed with a 512 × 512 matrix and a 0.5 mm slice thickness. Spatial resolution, noise power spectrum, and objective high-contrast detectability were compared. Three radiologists evaluated the clinical acceptability of these algorithms by assessing the thickness and image quality of the stapes footplate and superstructure elements, as well as the image quality of the chorda tympani nerve bony and tympanic segments using a 5-point confidence scale on 13 temporal bone CT examinations reconstructed with the four algorithms. RESULTS: UHR-CT provided higher spatial resolution than simulated conventional CT at the penalty of higher noise. DLR and model-based iterative reconstruction provided better noise reduction than hybrid iterative reconstruction, and DLR had the highest detectability index, regardless of the dose level. All stapedial structure thicknesses were thinner using UHR-CT by comparison with conventional simulated CT (P < 0.009). DLR showed the best visualization scores compared to the other reconstruction algorithms (P < 0.032). CONCLUSION: UHR-CT with DLR results in less noise than UHR-CT with hybrid iterative reconstruction and significantly improves stapes and tympanic chorda tympani nerve depiction compared to simulated conventional CT and UHR-CT with iterative reconstruction.