RPS 808 - Imaging the skull base and face

Author Block: S. Zhou¹, L. Mei¹, H. Liu¹, X. M. Liu², J. Li¹; ¹Changsha/CN, ²Guangzhou/CN
Purpose: To compare the diagnostic performance of dual-layer spectral detector CT (DLCT) and high-resolution CT (HRCT) in differentiating middle ear cholesteatoma and chronic suppurative otitis media.
Methods or Background: This prospective, institutional review board-approved study included sixty-six patients who were preliminary diagnosed as cholesteatoma or otitis media, and received DLCT scanning before surgery. Thirty-three patients were finally diagnosed cholesteatoma based on intraoperative or pathological findings. Two blinded readers (Reader 1: one radiologist; Reader 2: one otologist) provided diagnoses and diagnostic confidence scores using a five-point scale, based on HRCT images and DLCT multi-parameter images, including virtual mono-energetic image at 40keV (VMI 40keV) and effective atomic number (Zeff). Diagnostic accuracy of HRCT and DLCT maps were compared using McNemar’s test. Interobserver agreement was evaluated by Kappa statistic.
Results or Findings: HRCT and DLCT identified a total of 27/33 and 31/33 cholesteatomas by Reader 1, 19/33 and 30/33 cholesteatomas by Reader 2 respectively. The sensitivity, specificity, PPV, NPV, accuracy of HRCT and DECT by Reader 1 were 81.8, 75.8, 77.1, 68.2, 78.8% and 93.9, 69.7, 75.6, 92.0, 87.5%, by Reader 2 were 57.6, 90.9, 86.3, 68.2, 74.2% and 90.9, 75.8, 78.9, 89.3, 83.3%, respectively. Compared to HRCT, the diagnostic sensitivity of DLCT increased for both readers, with a statistically significantly improvement in Reader 2 (p＜0.05). Diagnostic confidence scores of DLCT versus HRCT by Reader 1 and Reader 2 both improved significantly (4.85±0.36 vs 3.77±1.30, 4.44±0.73 vs 3.45±0.98, respectively, all p＜0.05). Interobserver reproducibility was higher for diagnoses made with DLCT maps (k =0.717) than for that made with HRCT images (k = 0.495).
Conclusion: Spectral CT improved diagnostic performance and interobserver reproducibility of determination of cholesteatoma versus otitis media.
Limitations: None
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: lRB of Xiangya Hospital

Author Block: P. Rondi¹, E. Massoni¹, A. Borghesi¹, P. Bossi², C. Resteghini², D. Farina¹, M. Ravanelli¹; ¹Brescia/IT, ²Milan/IT
Purpose: Aim of this study is to identify the best response criteria in patients with sinonasal cancer undergoing induction chemotherapy (IC).
Methods or Background: Patients enrolled in SINTART-1 and SINTART-2 were included in this study. Unidimensional diameters (antero-posterior, AP; latero-lateral, LL; cranio-caudal, CC), maximum axial area (Amax) and volume (V) were performed on MRI by two radiologists. RECIST 1.1 assessment was included as a categorical variable. Variables were evaluated at baseline, after 1st chemotherapy cycle and at best response. Interobserver repeatability was analyzed.
Stepwise univariable and multivariable Cox proportional-hazards regression models were used to correlate variables with Disease-Free Survival (DFS) and Overall Survival (OS).
Results or Findings: 60 patients were included in this study. Interobserver correlation at baseline and after 1st IC cycle was excellent for V (0.916 and 0.928 respectively), CC diameter (0.96 and 0,863) and AP diameter (0.846 and 0.796); good for LL diameter and moderate for Amax.
RECIST 1.1 criteria after 1st IC cycle and at best response were not correlated with OS and DFS. Volume variation after 1st IC cycle and at best response was the variable most correlated with OS (p<0.0001and p=0.002) and DFS (p<0.0001and p=0.005).
At the multivariable analysis V variation after 1st IC cycle and at best response resulted to be the only variable statistically associated with OS (p<0.001 and p=0.0019 respectively) and DFS (p=0.0004and p=0.004respectively).
Conclusion: Volume variation should be preferred to RECIST 1.1 and other measurements as objective radiological response in sinonasal cancer.
Limitations: The main limitation of this study is that despite considering two prospective studies the size of the cohort is small and this could reduce the statistical power.
Funding for this study: This study has received no funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The ethics committee of participating centers have approved this study

Author Block: U. B. Abdullaeva¹, B. Pape², J. Hirvonen³; ¹Tashkent/UZ, ²Turku/FI, ³Tampere/FI
Purpose: To review the diagnostic accuracy of MRI in detecting orbital and intracranial invasion of sinonasal malignancies using histopathological or surgical evidence as the reference standard.
Methods or Background: The systematic review protocol was pre-registered in the Prospective Register of Systematic Reviews (PROSPERO) under registration number CRD42024492090. A systematic search of the studies in English was conducted in PubMed and Embase, limited to articles published since 1990. We included studies that used preoperative MRI to detect intracranial and orbital invasion of sinonasal malignancies, using histological or surgical confirmation as the reference standard, and reported patient numbers in each class required for assessing diagnostic accuracy. The outcome measures were sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Heterogeneity was assessed with the Higgins inconsistency test (I2).
Results or Findings: Seven original articles with 546 subjects were included in the review, six of these in the meta-analysis. Pooled overall accuracy for orbital invasion was higher at 0.88 (95% CI, 0.75-0.94) than for intracranial invasion - 0.80 (95% CI, 0.76-0.83). Meta-analytic estimates and their 95% confidence intervals were as follows for intracranial/orbital invasion: sensitivity 0.77 (0.69-0.83)/ 0.71 (0.40-0.90); specificity 0.79 (0.74-0.83)/0.91 (0.78-0.97); PPV 0.76 (0.64-0.85)/0.78 (0.61-0.88); and NPV 0.82 (0.72-0.89)/0.90 (0.63-0.98). Significant heterogeneity was observed in the Higgins inconsistency test (I2) for orbital invasion (84%, 83%, and 93% for sensitivity, specificity, and NPV, respectively).
Conclusion: MRI yielded moderate to high diagnostic accuracy for intracranial and orbital invasion, but there are limitations leading to false diagnoses. Loss of the hypointense zone on MRI predicts dural invasion. Infiltration of the extraconal fat beyond the periorbita is an MRI feature of orbital invasion.
Limitations: Limitations include a small number of predominantly retrospective studies, some with a small subset of patients.
Funding for this study: Funding was provided by the Sigrid Jusélius Foundation, grant number 240053.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Since this is a systematic review, Institutional Review Board approval was not necessary.

Author Block: M. Saini, S. Manchanda, A. S. Bhalla, D. Kandasamy; New Delhi/IN
Purpose: Sinonasal area is affected by a wide spectrum of benign and malignant tumours presenting with nonspecific symptoms and differentiation solely based on conventional magnetic resonance imaging has only limited specificity

To evaluate the role of newer imaging techniques like intravoxel incoherent motion (IVIM), diffusion kurtosis imaging (DKI) and dynamic contrast enhanced MRI (DCE-MRI) in differentiating benign and malignant sinonasal masses
Methods or Background: A prospective study was performed on 30 patients with sinonasal masses (18 malignant and 12 benign) who underwent routine MRI, DWI, IVIM and DCE MRI. Apparent diffusion coefficient (ADC) from diffusion weighted imaging, true diffusion coefficient (Dt), Pseudodiffusion coefficient (Dx), perfusion fraction (f) from IVIM, apparent kurtosis coefficient (Kapp) and apparent diffusion coefficient (Dapp) from DKI, semiquantitative and quantitative perfusion parameters from DCEMRI were measured and compared between two groups.
Results or Findings: The mean ADC, Dt and Dapp values were significantly lower in malignant sinonasal lesions than in benign sinonasal lesions with p values of 0.000, 0.015 and 0.030 respectively. The mean Kapp value was higher in malignant lesions than in benign lesions (p value of 0.001). There was no significant difference Dx, f and in semiquantitative and quantitative perfusion parameters.
Conclusion: The mean ADC derived from the DWI, Dt derived from IVIM, and Dapp & Kapp derived from the DKI can be used as a non-invasive method to differentiate benign and malignant sinonasal masses. Among these, ADC is the best parameter to differentiate, however there is no incremental role of DKI and IVIM over conventional DWI. The perfusion parameters showed no significant difference
Limitations: The sample size was small and a heterogeneous group of pathologies were included in the final analysis. In addition, the b values were set arbitrarily in the IVIM-DKI sequence.
Funding for this study: No funding was provided for this study
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Study was preapproved by the Institute Review Board (IRB) [Ref No: IECPG-487/25.08.2021].

Author Block: H. S. Leung, K. K. F. Tsoi, Q-Y. H. Ai, A. D. King; Hong Kong/HK
Purpose: Osteoradionecrosis is one the long-term complications associated with radiotherapy for nasopharyngeal carcinoma (NPC), and may result in the significant complications particularly skull base osteomyelitis (SBOM). A limited number of clinical case series have reported on SBOM and their predictors, imaging features and associations with other radiation-induced complications remain poorly understood. This study is to evaluate the imaging factors associated with SBOM in patients with previous irradiation for NPC.
Methods or Background: This is a retrospective matched case-control study, of patients with clinically proven SBOM and computer tomography (CT) scan performed at diagnosis selected as cases, while controls were selected within NPC post-RT patients and without SBOM, matched by initial staging and time from initial treatment. CT studies were reviewed for the presence of bone exposure to aerodigestive tract, bony sclerosis, bone loss and dehiscence and abscess formation; baseline demographics and clinical outcomes were analyzed by logistic regression and survival analyses.
Results or Findings: A total of 31 SBOM cases and 31 controls were analysed. Presence of bone exposure to aerodigestive tract is the only independent factor associated with SBOM (p<0.001 by McNemar’s test), while the degree of bone loss also shows borderline significance (p=0.052 by Wilcoxon sign rank test). Bone exposure to upper aerodigestive tract remains significant upon regression controlling for bone loss and staging of initial NPC. SBOM patients had worse survival with a higher incidence of other RT-related complications including carotid occlusion, blowout or RT-induced malignancy.
Conclusion: The presence of bone exposure to upper aerodigestive tract is an independent factor associated with SBOM, which could be helpful in early identification and treatment to avoid complications of SBOM which adversely affects survival.
Limitations: Recall bias from retrospective study.
Funding for this study: Nil
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study has been approved by Joint CUHK-NTEC Clinical Research Ethics Committee; The Chinese University of Hong Kong (Reference number: CREC 2024.306)

Author Block: C. Nadler, Y. Pakanaev-Levi, H. Rushinek, N. Yavnai, Y. Zadik, I. Zeevi; Jerusalem/IL
Purpose: Bone lesions demonstrated on Computed Tomography (CT) images may be differentiated by several methods including Hounsfield Unit (HU) analysis. However, the routine use of this method in pre-operative assessment of jaw lesions remains underexplored. We aimed to distinguish using HU analysis 3 types of jaw lesions.
Methods or Background: We retrospectively included pre-operative Multidetector CT (MDCT) scans of patients with unilocular hypodense jaw lesions, with histologically proven, non-inflame either odontogenic keratocyst OKC, central giant cell granuloma CGCG or unicystic ameloblastoma UA. Demographic data and anonymized DICOM files were retrieved. Two observers, blinded to the lesions’ diagnosis, measured three HU values for each lesion, in axial slices, on Philips IntelliSpace Portal software. Statistical analysis included intra and inter-observer reliability and validity evaluations as well as comparisons of mean HU values between the different lesions and between the same lesion in different jaws
Results or Findings: Our cohort included 30 jaw lesions (17 OKCs, 8 CGCGs and 5 UAs). Mean HU values for OKCs, CGCGs and UAs were 27.99±13.8, 70.68±46.3 and 31.38±7.4, respectively. Statistically significant difference was found between mean HU values of OKC, CGCG and UA (P=0.035). Following additional pooled analysis, mean HU values of CGCG was statistically higher than OKC and UA (<0.001). No statistically difference was found between HU values of different lesions in different jaws.
Conclusion: Pre-operative differentiation using HU analysis may be used to diagnose CGCG from OKC and UA. Future multi-center studies with additional types of lesions are needed to substantiate our results
Limitations: Our limitation included: small sample size, as is a result of stringent inclusion criteria and the transition of referrals from MDCT to CBCT and the fact that all cases were from a single medical center.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study protocol was approved by the Institutional Review Board

Author Block: X-Y. Pu, H. Hu, J. Zhou, L. Jinling, X-Q. Xu, F-Y. Wu; Nanjing/CN
Purpose: To evaluate the performance of dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in determining disease activity of thyroid-associated ophthalmopathy (TAO) and to establish their additional value for staging TAO compared to conventional T2-weighted imaging (T2WI).
Methods or Background: Seventy-two patients with TAO (48 active, 96 eyes; 24 inactive, 48 eyes) who underwent DCE, DWI and T2WI with fat suppression were prospectively enrolled. Simplified histogram parameters (mean, max, min) of DCE-MRI derived parameters (Ktrans, Kep, Ve), apparent diffusion coefficient (ADC) and signal intensity ratio (SIR) at extraocular muscles were calculated for each orbit and compared between the active and inactive groups. Multivariate analyses were used to identify independent predictors. Receiver operating characteristic curves analyses and DeLong tests were performed to evaluate and compare the performances of the identified significant imaging parameters and their combinations.
Results or Findings: Active TAO patients showed significantly higher mean and maximum Ve, higher minimum, mean and maximum ADC, higher minimum, mean and maximum SIR than inactive patients (P < 0.05). The mean Ve, mean ADC and mean SIR were found to be independent predictors for active TAO (all P < 0.05). Combination of mean Ve, mean ADC and mean SIR outperformed mean SIR alone in staging TAO (AUC, 0.839 vs 0.769, P = 0.016).
Conclusion: DCE-MRI and DWI could help to determine the disease activity of TAO. DCE-MRI-derived Ve and DWI-derived ADC values could provide added value to conventional T2WI-derived SIR in staging TAO
Limitations: First, the sample size was relatively small. More research should be done to increase the number of datasets to verify our findings. Second, only multiparametric MRI-derived simplified histogram metrics were analysed. Future studies integrating radiomics and machine learning have the potential to further improve staging performance.
Funding for this study: Jiangsu Province Hospital (the First Affiliated Hospital with Nanjing Medical University) Clinical Capacity Enhancement Project (JSPH-MC-2021-8 to Xiao-Quan Xu) , Jiangsu Province Capability Improvement Project through Science, Technology and Education (JSDW202243 to Fei-Yun Wu) and National Natural Science Foundation of China (NSFC) (81801659 to Hao Hu),
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Institutional Review Board of the First Affiliated Hospital of Nanjing Medical University (IRB No.2021-SRFA-024)