Temporal Computed Tomography Research Articles

Training and validation of a deep learning U-net architecture general model for automated segmentation of inner ear from CT

BackgroundThe intricate three-dimensional anatomy of the inner ear presents significant challenges in diagnostic procedures and critical surgical interventions. Recent advancements in deep learning (DL), particularly convolutional neural networks (CNN), have shown promise for segmenting specific structures in medical imaging. This study aimed to train and externally validate an open-source U-net DL general model for automated segmentation of the inner ear from computed tomography (CT) scans, using quantitative and qualitative assessments.MethodsIn this multicenter study, we retrospectively collected a dataset of 271 CT scans to train an open-source U-net CNN model. An external set of 70 CT scans was used to evaluate the performance of the trained model. The model’s efficacy was quantitatively assessed using the Dice similarity coefficient (DSC) and qualitatively assessed using a 4-level Likert score. For comparative analysis, manual segmentation served as the reference standard, with assessments made on both training and validation datasets, as well as stratified analysis of normal and pathological subgroups.ResultsThe optimized model yielded a mean DSC of 0.83 and achieved a Likert score of 1 in 42% of the cases, in conjunction with a significantly reduced processing time. Nevertheless, 27% of the patients received an indeterminate Likert score of 4. Overall, the mean DSCs were notably higher in the validation dataset than in the training dataset.ConclusionThis study supports the external validation of an open-source U-net model for the automated segmentation of the inner ear from CT scans.Relevance statementThis study optimized and assessed an open-source general deep learning model for automated segmentation of the inner ear using temporal CT scans, offering perspectives for application in clinical routine. The model weights, study datasets, and baseline model are worldwide accessible.Key PointsA general open-source deep learning model was trained for CT automated inner ear segmentation.The Dice similarity coefficient was 0.83 and a Likert score of 1 was attributed to 42% of automated segmentations.The influence of scanning protocols on the model performances remains to be assessed.Graphical

Performance evaluation of a 4D similarity filter for dynamic CT angiography imaging of the liver.

Dynamic computed tomography (CT) angiography of the abdomen provides perfusion information and characteristics of the tissues present in the abdomen. This information could potentially help characterize liver metastases. However, radiation dose has to be relatively low for the patient, causing the images to have very high noise content. Denoising methods are needed to increase image quality. The purpose of this study was to investigate the performance, limitations, and behavior of a new 4D filtering method, called the 4D Similarity Filter (4DSF), to reduce image noise in temporal CT data. The 4DSF averages voxels with similar time-intensity curves (TICs). Each phase is filtered individually using the information of all phases except for the one being filtered. This approach minimizes the bias toward the noise initially present in this phase. Since the 4DSF does not base similarity on spatial proximity, loss of spatial resolution is avoided. The 4DSF was evaluated on a 12-phase liver dynamic CT angiography acquisition of 52 digital anthropomorphic phantoms, each containing one hypervascular 1cm lesion with a small necrotic core. The metrics used for evaluation were noise reduction, lesion contrast-to-noise ratio (CNR), CT number accuracy using peak-time and peak-intensity of the TICs, and resolution loss. The results were compared to those obtained by the time-intensity profile similarity (TIPS) filter, which uses the whole TIC for determining similarity, and the combination 4DSF followed by TIPS filter (4DSF + TIPS). The 4DSF alone resulted in a median noise reduction by a factor of 6.8, which is lower than that obtained by the TIPS filter at 8.1, and 4DSF + TIPS at 12.2. The 4DSF increased the median CNR from 0. 44 to 1.85, which is less than the TIPS filter at 2.59 and 4DSF + TIPS at 3.12. However, the peak-intensity accuracy in the TICs was superior for the 4DSF, with a median intensity decrease of -34 HU compared to -88 and -50 HU for the hepatic artery when using the TIPS filter and 4DSF + TIPS, respectively. The median peak-time accuracy was inferior for the 4DSF filter and 4DSF + TIPS, with a time shift of -1 phases for the portal vein TIC compared to no shift in time when using the TIPS. The analysis of the full-width-at-half-maximum (FWHM) of a small artery showed significantly less spatial resolution loss for the 4DSF at 3.2 pixels, compared to the TIPS filter at 4.3 pixels, and 3.4 pixels for the 4DSF + TIPS. The 4DSF can reduce noise with almost no resolution loss, making the filter very suitable for denoising 4D CT data for detection tasks, even in very low dose, i.e., very high noise level, situations. In combination with the TIPS filter, the noise reduction can be increased even further.

Temporal CT Evaluation of the Relationships between Basic Anatomical Structures and the Round Window: Importance for the Cochlear Implant Surgery

Abstract Objectives In the present study, we investigated the round window (RW) and neighboring anatomical structures using temporal computed tomography (CT) which are important for cochlear implant (CI) electrodes. Methods In this retrospective study, the temporal CT images of 112 adult patients (45 males and 67 females) were evaluated. We classified mastoid pneumatization, and measured RW diameter, RW–carotid canal (CC) distance, RW–facial nerve mastoid segment (FNMS) distance, RW–pyramidal eminence distance, RW–jugular bulb (JB) distance, and RW–internal acoustic canal (IAC) distance. Additionally, RW–cochlea angle and RW–facial nerve angle were also measured. Results RW diameters in males were significantly higher than those in females bilaterally (p < 0.05). RW–CC distance and RW–JB distance were both smaller than 10 mm. RW–IAC distance was 2.54 to 2.68 mm, and RW–FNMS distance was 4.20 to 4.40 mm. RW–cochlea angle ranged from 39.62 to 41.91 degrees and RW–FN angle ranged from 17.28 to 18.40 degrees. Males showed better mastoid pneumatization values (p < 0.05). In higher RW diameters, RW–JB distance decreased, and in pneumatized mastoids, RW–JB distance increased. RW–JB distance and RW–CC distance were detected to increase together (p < 0.05). Conclusion RW is crucial anatomic structure for CI surgeries. RW diameters are between 1.21 and 1.35 mm and lower in the females. Males exhibited better mastoid pneumatization values than the females, and CC and JB distances from RW were farther in well-pneumatized mastoids. Future studies should include comprehensive clinical and surgical findings.

Evaluation of high placed jugular bulbus density with multislice temporal computed tomography

Aims: In this study, it is aimed to investigate the density of high placed jugular bulbus (HPJB), which is useful to know from a clinical and surgical perspective. Methods: Between the dates of May and November 2023, temporal computed tomography (CT) scans which took place in the CT (General Electric) were evaluated retrospectively.742 cases and 1484 ears were included in the study. Jugular bulbus (JB) was evaluated based on the internal acoustic canal (IAC). Results: The age range of 742 cases was 18-72. Of the cases, 796 were women and 688 were men. HPJB was detected in 44 (3%) of 1484 ears. Of the 44 ears in which HPJB was detected, 26 (59%) were located on the right and 18 (41%) were located on the left. HPJB were monitored more frequently on the right side. Conclusion: HPJB can cause various otological symptoms, especially tinnitus. Additionally, not knowing the existence of HPJB increases morbidity rates, especially in lateral skull base surgery. In various otological findings of unknown etiology and preoperatively before lateral skull base surgery, the jugular bulb should be evaluated with temporal CT.

The Compatibility of Preoperative Temporal Bone CT Scan Interpretation and Intraoperative Findings in Chronic Suppurative Otitis Media at Dr. Zainoel Abidin Hospital Banda Aceh

Introduction: Chronic suppurative otitis media (CSOM) is middle ear and mastoid infection that causes hearing loss globally. Computed Tomography (CT)-Scan of the temporal bone is useful for assessing the pathogenesis of the disease and estimating the prognosis. In addition, evaluation of CT-Scan in patients with CSOM is useful for selecting the appropriate surgical procedure to minimize post-surgical complications. This study aims to assess the suitability of temporal CT-Scan interpretation to intraoperatif findings in CSOM patients. Methods: This is an observational study with cross-sectional design conducted at the dr. Zainoel Abidin General Hospital, Banda Aceh. The components of suitability evaluation include cholesteatoma, scutum erosion, ossicles, tegmen tympani, facial canal, posterior wall and sigmoid sinus wall. The interpretation suitability of temporal CT-Scan and intraoperatif findings was performed using the Kappa test. Results: A total of 18 CSOM patients were involved in this study with a mean age of 32.44 years and dominated by the safe type with a percentage of 55.6%. Interpretation of ossicular erosion based on temporal CT scan has very strong suitability with the intraoperatif findings with k=0.88 followed by posterior wall erosion (k=0.684), scutum erosion (k=0.679), tympanic tegmen erosion (k=0.455) and facial canal erosion (k=0.341). The findings of cholesteatoma and erosion of the sigmoid sinus wall had a very low suitability (k<0.001). Conclusion: Temporal CT scan in CSOM patients has relatively good suitability with intraoperatif findings in evaluating erosion of the ossicles, posterior wall, and scutum. Another examination modality is necessary to assess and improve the accuracy of disease pathogenesis.

4D imaging of void nucleation, growth, and coalescence from large and small inclusions in steel under tensile deformation

• High spatial and temporal resolution synchrotron X-ray CT enabled 4D imaging of void nucleation, growth, and coalescence with unprecedented details. • Large inclusion particles in SA508 steel led to large and prolate voids which, while striking, did not affect crack formation. • The final fracture was induced by densely populated carbide precipitates that led to small but closely spaced voids which quickly coalesced to form micro-cracks. • The results challenge established theories on ductile fracture and could potentially lead to new strategies for steel making. Samples of SA508 grade 3 nuclear pressure vessel ferritic steel were subjected to tensile straining whilst being simultaneously imaged in 3D in real time using high resolution, high frame rate time-lapse synchrotron computed tomography (CT). This enabled direct observation of void development from nucleation, through growth to coalescence and final failure validating many inferences made post-mortem or by theoretical models, as well as raising new points. The sparse, large inclusions were found to nucleate voids at essentially zero plastic strain (consistent with zero interfacial strength); these became increasingly elongated with straining. In contrast, a high density of small spherical voids were found to nucleate from the sub-micron cementite particles at larger strains (> 200%) only in the centre of the necked (high triaxiality) region. An interfacial strength approaching 2100 MPa was inferred and soon after their nucleation, these small voids coalesce to form internal microcracks that lead to the final failure of the specimen. Perhaps surprisingly, under these conditions of generally low triaxial constraint the large voids are simply cut across and appear to play no significant role in determining the final failure. The implications of these results are discussed in terms of ductile fracture behaviour and the Gurson model for ductile fracture.

4DRoot: Root phenotyping software for temporal 3D scans by X-ray computed tomography.

Currently, plant phenomics is considered the key to reducing the genotype-to-phenotype knowledge gap in plant breeding. In this context, breakthrough imaging technologies have demonstrated high accuracy and reliability. The X-ray computed tomography (CT) technology can noninvasively scan roots in 3D; however, it is urgently required to implement high-throughput phenotyping procedures and analyses to increase the amount of data to measure more complex root phenotypic traits. We have developed a spatial-temporal root architectural modeling software tool based on 4D data from temporal X-ray CT scans. Through a cylinder fitting, we automatically extract significant root architectural traits, distribution, and hierarchy. The open-source software tool is named 4DRoot and implemented in MATLAB. The source code is freely available at https://github.com/TIDOP-USAL/4DRoot. In this research, 3D root scans from the black walnut tree were analyzed, a punctual scan for the spatial study and a weekly time-slot series for the temporal one. 4DRoot provides breeders and root biologists an objective and useful tool to quantify carbon sequestration throw trait extraction. In addition, 4DRoot could help plant breeders to improve plants to meet the food, fuel, and fiber demands in the future, in order to increase crop yield while reducing farming inputs.

Surgical importance of the tympanic bone: multidetector computed tomography findings.

ObjectivesTo measure tympanic bone thickness (anterior-superior, anterior-inferior, and inferior wall), external ear canal length, and tympanomandibular distance that can be useful in cases that undergo tympanic bone resection.Materials and MethodsThe temporal computed tomography (CT) images of 349 patients were retrospectively evaluated. The anterior-inferior, anterior-superior, and inferior wall thicknesses; tympanomandibular distance; and external auditory canal (EAC) bone canal length were measured from the narrowest part of the canal. The shapes of the EAC in the coronal and sagittal planes were also examined.ResultsThe numbers of female and male patients were similar, and the mean age was 49.45±13.95 years. The anterior-superior, anterior-inferior, and inferior wall thicknesses were 1.92±0.60, 2.54±0.74, and 9.16±2.20 mm, respectively. The anterior-superior and anterior-inferior wall thicknesses and canal lengths were greater on the right side (P<0.001). All measurement values were higher in males, except right tympanomandibular distance (P<0.05). A non-significant negative correlation was found between the age of the participants and the left anterior-inferior wall and tympanomandibular distance on both sides. Intra-observer agreement was high for all measurements. We observed four main shapes in the external ear canal in the coronal plane Type 3, Type 2, Type 1, and Type 4 in order of frequency on the right, and Type 2, Type 3, Type 1, and Type 4 on the left. In the sagittal plane, we detected three shapes oval (74.4%), triangular (16.3%), and round (9.4%).ConclusionThe anterior wall thicknesses and tympanomandibular distance should be measured on preoperative temporal bone CT to safely perform tympanic bone anterior resection, which is required in some otological procedures, and also to prevent temporomandibular joint damage.

The Role of Fusion Technique of Computed Tomography and Non-echo-planar Diffusion-weighted Imaging in the Evaluation of Surgical Cholesteatoma Localization.

Objective:In recent years, the fusion of computed tomography (CT) and non-echo-planar diffusion-weighted magnetic resonance imaging (non- EPI DWI) has been preferred in cholesteatoma localizations. This study aimed to investigate the role of CT and non-EPI DWI fusion imaging in cholesteatoma localizations.Methods:This retrospective study included 39 patients who underwent chronic otitis media operation [mean age of 35.10±15.33 years (18-67 years), 64.1% female, and 35.9% male] and had preoperative high-resolution temporal bone CT and non-EPI DWI examinations. Images were sent to the Advantage Workstation VolumeShare 7 for fusion. These selected images were fused on the workstation and were manually corrected by the radiologist. The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracies of fused images of CT and non-EPI DWI were evaluated according to anatomic cholesteatoma localizations based on surgical data.Results:The sensitivity, specificity, positive and negative predictive values, and diagnostic accuracies of non-EPI DWI for detecting cholesteatomas were 97.14%, 75.00%, 97.14%, 75.00%, and 94.87%, respectively. Three true-negative, one false-positive, and one false-negative case were observed according to surgical results in detecting the presence of a cholesteatoma with non-EPI DWI. Moderate agreement was determined between the surgical and radiological results in detecting the presence of a cholesteatoma (k=0.721). Detecting the lesion of localization on the fused images compared to surgical found an almost perfect agreement in the mastoid antrum (k=0.948), strong agreement in the hypotympanum and mastoid cells (k=0.894), moderate agreement in the epitympanum (k=0.653), and weak agreement in those in the mesotympanum (k=0.540).Conclusions:The surgeons’ determinations are supported by the guidance of temporal CT and non-EPI DWI fused images. Therefore, preferring the fusion imaging technique could increase the quality of life by reducing unnecessary operations.

Mitochondrial encephalomyopathy involves ophthalmology otorhinolaryngology neurology and their clinical features

Objective:This study aimed to provide better understanding of the otolaryngologic features, combined with ophthalmologic and neurologic characteristics in mitochondrial encephalomyopathy（MEM）, and to help ENT and auditory practitioner making correct diagnosis as well. Methods:Twenty-eight patients with MEM were enrolled between September 2001 and January 2020. Information about family histories and clinical symptoms was retrospectively analyzed. All patients underwent otorhinolaryngological, ophthalmological and neurological examinations, including: pure-tone audiometry, acoustic immittance（AI）, distortion-product otoacoustic emissions（DPOAE）, auditory brainstem response（ABR）, cochlear micropotential（CM）, speech discrimination score（SDS）, electroneurography（ENoG）, computed tomography（CT） of the temporal bone and cranial magnetic resonance weighted imaging scan（MRI）, muscle biopsy and mtDNA gene testing. Results:ENT subjective manifestations were present in 15 cases （53.6%） with sensorineural hearing loss（SNHL）, 4（14.3%） with tinnitus, 4（14.3%） with facial weakness, 3（10.7%） with dysphagia, 1（3.6%） with auditory agnosia. Ophthalmological and neurological symptoms included ptosis in 16 cases （57.1%）, exercise intolerance in 16（57.1%）, optic atrophy in 15（53.6%）, muscular atrophy in 6（21.4%）, and stroke-like episodes in 5（17.9%）. The results of objective examinations were as follows: DPOAE were not elicited in 18（64.3%） cases, ABR abnormalities in 18（64.3%） cases, hearing threshold shift in 15（53.6%） cases, AI normal and CM was not detected in all cases, SDS decreased in 6（21.4%） cases, facial ENoG abnormalities in 4（14.3%） cases, laryngeal ENoG abnormalities in 3（10.7%） cases, EMG abnormalities in 6（21.4%） cases, and ECG abnormalities in 8（28.6%） cases. Temporal CT were normal, but cranial MRI abnormalities were found in 19 cases（67.9%）, including central nerve demyelination, white matter hyperintensities, generalized cerebellar and cerebral atrophy, multiple cortical/subcortical infarct-like lesions, basal ganglia calcification. Conclusion:Multisystemic syndromes in MEM can present as a variety of otolaryngological, ophthalmological and neurological abnormalities, such as ptosis, audio-visual disturbance, exercise intolerance and stroke-like episodes etc. SNHL, tinnitus, auditory agnosia, facial weakness and dysphagia were ENT specific manifestations. SNHL in MEM is bilateral symmetrical progressive or of sudden onset since teenage. mtDNA testing may be helpful for adolescent patient whose SNHL was associated with neuromuscular symptoms. Muscle biopsy should be considered when middle-aged patients developed facial weakness and dysphagia. DPOAE and ABR are the optimal objective audiometric tests to monitor the progression of MEM associated with SNHL.

Traumatic dislocation of middle ear ossicles: A new computed tomography classification predicting hearing outcome.

To assess the feasibility of radiologic measurements and find out whether hearing outcome could be predicted based on computer tomography (CT) scan evaluation in patients with temporal bone fractures and suspected ossicular joint dislocation. We assessed 4002 temporal bone CT scans and identified 34 patients with reported ossicular joint dislocation due to trauma. We excluded those with no proven traumatic ossicular dislocation in CT scan and patients with bilateral temporal bone fractures. We measured four parameters such as malleus-incus axis distance, malleus-incus angle at midpoints, malleus- incus axis angle and ossicular joint space. The contralateral healthy side served as its own control. Hearing outcome 1-3 months after the index visit was analyzed. We assessed diagnostic accuracy and performed a logistic regression using radiologic measurement parameters for outcome prediction of conductive hearing loss (defined as >20dB air-bone gap). We found excellent inter-rater agreement on the measurement of axis deviation between incus and malleus in CT scans (interclass correlation coefficient 0.81). The larger the deviation of incus and malleus axis, the higher probability of poor hearing outcome (odds ratio (OR) 2.67 per 0.1mm, p = .006). A cut-off value for the axis deviation of 0.25mm showed a sensitivity of 0.778 and a specificity of 0.94 (p < .001) for discrimination between poor and good hearing outcome in terms of conductive hearing loss. Adequate assessment of high resolution CT scans of temporal bone in which ossicular chain dislocation had occurred after trauma was feasible. Axis deviations of the incus and the malleus were strongly predictive for poor hearing outcome in terms of air conduction 1-3 months after trauma. We propose a 3-level classification system for hearing outcome prediction based on radiologic measures.

Feature-based automated segmentation of ablation zones by fuzzy c-mean clustering during low-dose computed tomography.

Intra-procedural monitoring and post-procedural follow-up is necessary for a successful ablation treatment. An imaging technique which can assess the ablation geometry accurately is beneficial to monitor and evaluate treatment. In this study, we developed an automated ablation segmentation technique for serial low-dose, noisy ablation computed tomography (CT) or contrast-enhanced CT (CECT). Low-dose, noisy temporal CT and CECT volumes were acquired during microwave ablation on normal porcine liver (four with non-contrast CT and eight with CECT). Highly constrained backprojection (HYPR) processing was used to recover ablation zone information compromised by low-dose noise. First-order statistic features and normalized fractional Brownian features (NBF) were used to segment ablation zones by fuzzy c-mean clustering. After clustering, the segmented ablation zone was refined by cyclic morphological processing. Automatic and manual segmentations were compared to gross pathology with Dice's coefficient (morphological similarity), while cross-sectional dimensions were compared by percent difference. Automatic and manual segmentations of the ablation zone were very similar to gross pathology (Dice Coefficients: Auto.-Path.=0.84±0.02; Manu.-Path.=0.76±0.03, P=0.11). The differences in ablation area, major diameter and minor diameter were 17.9±3.2%, 11.1±3.2% and 16.2±3.4%, respectively, when comparing automatic segmentation to gross pathology, which were lower than the differences of 32.9±16.8%, 13.0±9.8% and 21.8±5.8% when comparing manual segmentation to gross pathology. Manual segmentations tended to overestimate gross pathology when ablation area was less than 15 cm2 , but the automated segmentation tended to underestimate gross pathology when ablation zone is larger than 20 cm2 . Fuzzy c-means clustering may be used to aid automatic segmentation of ablation zones without prior information or user input, making serial CT/CECT has more potential to assess treatments intra-procedurally.

Design, simulation and reconstruction for a fast speed two-phase flow CT with 241Am gamma ray sources

Computer tomography (CT) is a useful probe to measure two-phase flow parameters. Because of the dynamic characteristic of the two-phase flow, the high temporal CT is required. A compact CT system, consists of seven isotope γ-ray sources, seven groups of cadmium zinc telluride (CdZnTe) detectors and collimators, is proposed. The 241Am is selected as the source by balancing its ability to distinguish water and air and transmission power for the acrylic pipeline. The virtual pixels are interpolated to increase the number of projections from Monte Carlo simulation. The reconstruction accuracy and speed for different phantoms with maximum likelihood expectation maximization (MLEM), Tikhonov regularization, total variation (TV) regularization and genetic algorithm (GA) are compared. The results show TV algorithm achieves a good balance between accuracy and speed, and GA has the highest accuracy but lowest speed in high spatial resolution reconstruction. The temporal resolution can be increased by sacrificing the spatial resolution.

Clinical effects of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck

Objective: To explore the clinical effects of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck. Methods: From January 2016 to August 2019, 10 male patients, aged from 20 to 52 years with post-burn facial and cervical scar deformities, were admitted to the First People's Hospital of Zhengzhou, with the size of scar ranging from 15 cm×7 cm to 23 cm×11 cm. In the first stage, a cylindrical skin and soft tissue expander with rated capacity ranging from 400 to 600 mL was placed in the frontal-parietal region. Another cylindrical expander with rated capacity ranging from 50 to 100 mL was placed in the temporal region of the patient with scars in front of the ear and in cheek. The injection time was 3 to 5 months with the total injection volume being 1.5 to 2.5 times of the rated capacity of expander. In the second stage, the superficial temporal artery frontal branch and its branches were explored, the expander was removed, the scars in the face and neck were conducted resection and contracture relaxation, and the single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region for reconstruction was performed. When the branches of the superficial temporal vessels were difficult to be detected by Doppler ultrasonic blood stream detector, the patient underwent computed tomography (CT) angiography and three-dimensional reconstruction. The donor site in frontal-parietal region was directly sutured, and the wound of the exposed donor site at the pedicle and temporal region was temporarily covered with scar skin. After the suture wound was healed and the hair in expanded flap grew out, hair removal and laser hair removal were performed. Three to four weeks after transplantation of expanded flap, the flap pedicle was cut off, restored, and trimmed in the third stage. The status about the completion of operation, the implantation of expander in the temporal region, CT angiography and three-dimensional reconstruction were recorded. The effective resection area of expanded flap, the length across the midline and the length of the pedicle, and the survival status of the expanded flap and complications after operation were observed. The appearance of donor and recipient sites, the scar recurrence, the appearance and function improvement of patients, and the satisfaction degree of patients were followed up. Results: All the 10 patients successfully completed three stages of operation, of which 6 patients had an auxiliary expander placement in the temporal region, and 5 patients underwent CT angiography and three-dimensional reconstruction. The effective resection area of expanded flap ranged from 18 cm×8 cm to 25 cm×13 cm. The distal end of the flap across the midline extended 4-6 cm to the opposite side, and the length of pedicle was 2-6 cm. All the expanded flaps of patients survived well after formation and transfer. The venous reflux disorder and obvious swelling occurred in 6 patients at the distal end of the flap after operation, and the blood supply recovered after acupuncture bloodletting, etc. Follow-up of 6 to 24 months showed that the color, texture, and thickness of the expanded flaps were similar to those of the facial skin, and no recurrence of scar was observed; the incision in the donor site of the frontal-parietal region was concealed, the hair growth of the temples and head was normal, and the reconstructed hairline was natural; compared with those before operation, the appearance, head-up, mouth-opening, and other functions of patients were significantly improved; the patients were satisfied with the effect of reconstruction. Conclusions: Clinical application of single pedicle transfer of expanded axial flap across the midline of the frontal-parietal region in reconstruction of large scar deformities in the face and neck can achieve a good appearance and function, and the donor site shows good shape, which enriches the application range of the trans-regional blood supply flap. It is a reliable method for reconstruction of large scar deformities in the face and neck.

Optimal Imaging at the Primary Stroke Center.

Optimal Imaging at the Primary Stroke Center.

Anatomical landmarks for cochlear implantatıon in ossifıed cochleas.

In this study, we aimed to introduce the facial nerve as a new anatomical landmark which can be used in ossified cochleas during cochlear implantation. We also set out to define a safe line to preserve the internal auditory canal (IAC) while drilling the basal turn of the cochlea. Thirty patients who had temporal computed tomography (CT) were studied. The distances from the facial nerve and the round window to the IAC, carotid artery, and jugular bulb were measured in the reformatted CT images. We have created a line in the direction of the stapedial tendon from the round window to the IAC and called it ROWIAC (Round window-IAC) line. We have investigated whether this line intersects the IAC and measured the distances from this line to the IAC. Fifty-four temporal CT scans were included to the study. The mean distances from the facial nerve to the IAC, carotid artery, and jugular bulb were 8.8 ± 0.9, 15.0 ± 2.0, and 12.2 ± 2.9mm, respectively. The mean distances from the round window to these structures were 3.8 ± 0.7, 9.4 ± 2.2, and 8.3 ± 2.9mm, respectively. ROWIAC line did not intersect the IAC in any of the patients. The mean distance between this line and the IAC was 0.8 ± 0.4mm. We propose that facial nerve and ROWIAC line can be used as potential landmarks during cochlear implantation in ossified cochleas to protect the adjacent neurovascular structures.

Contribution of Reformatted Multislice Temporal Computed Tomography Images in the Planes of Stenvers and Pöschl to the Diagnosis of Superior Semicircular Canal Dehiscence.

In the diagnosis of superior semicircular canal dehiscence (SSCD), computed tomography (CT) is the only imaging method. The aims of the study were to show that reformat images are more accurate than standard planes for diagnosis of SSCD and to determine the prevalence of SSCD. The retrospective review yielded 1309 temporal CTs performed in our radiology department for any reason. Two radiologist interpreted CTs in standard planes collaboratively. Patients with SSCD were reinterpreted in Pöschl and Stenvers planes by 2 radiologists separately. Statistical analysis was made by accepting that 2 radiologists diagnosis were accurate in Pöschl plane. Coronal plane sensitivity 86%, specificity 64%, Stenvers plane sensitivity 96%, and specificity 52% have been found in the mean result of 2 observers (P < 0.001). In the diagnosis of SSCD, standard and Stenvers planes can cause false-negative and false-positive diagnoses. Interpretation in Pöschl plane can significantly increase sensitivity, specificity, negative, and positive predictive values for diagnosing dehiscence.

Clinical usefulness of temporal subtraction CT in detecting vertebral bone metastases

PurposeThe purpose of this study was to determine whether temporal subtraction (TS) computed tomography (CT) contributes to the detection of vertebral bone metastases. MethodThe calculation of TS CT was composed of bony landmark detection, bone segmentation with a multiatlas-based method, and spatial registration. Temporal increase and decrease of the CT values were visualized in blue and red, respectively. Paired CT images of 20 patients with cancer and newly-developed vertebral metastases were analyzed. Control CT examinations of 20 different patients were also included. The presence of vertebral metastases on the TS CT was evaluated by two board-certified radiologists. Five additional board-certified radiologists and five radiology residents independently interpreted the 40 paired CT images with and without TS CT. ResultsIn the lesion conspicuity evaluation, 96% of vertebral metastases were scored as excellent or good. In the image interpretation examination, according to free-response receiver operating characteristics analysis, the overall figure of merit (FOM) of the board-certified radiologist group was 0.892 and 0.898 with and without TS CT, respectively. The FOM of the resident group improved from 0.849 to 0.902 with viewing TS CT. In the sub-analysis focusing on the location of the lesion, the FOM of the resident group significantly improved from 0.75 to 0.92 in vertebral arch lesions (p = 0.001). ConclusionsThe TS CT may be useful to detect vertebral metastases because almost all the vertebral metastases were shown to be favorable visualization. The TS CT was proven to be especially helpful for radiology residents in detecting vertebral arch metastases.

Variations of the vascular canals in the cochlear implant candidates

ObjectiveTo evaluate the incidence of vascular canal variations in the pediatric cochlear implant (CI) candidates. MethodsWe retrospectively reviewed temporal bone computed tomography (CT) images of the CI candidates between November 2013 and November 2018. The presence of high riding jugular bulb, dehiscent jugular bulb, jugular bulb diverticulum, bulging of sigmoid sinus, mastoid emissary vein (MEV), carotid canal dehiscence, and aberrant internal carotid canal were evaluated. Findings were compared with a control group of normal-hearing subjects. ResultsTemporal CT images of 118 CI candidates and 119 control group participants were evaluated. The vascular canal anomalies were found in 88 (37.3%) temporal bones of the CI candidates and 49 (20.6%) of the control group (p < 0.001). In 236 temporal CT scans of the CI candidates and 238 temporal CT scans of the control group, we found MEV in 19.1% and 6.3%, high riding jugular bulb in 11.4% and 10.5%, dehiscent jugular bulb in 2.1% and 1.3%, jugular bulb diverticulum in 6.4% and 1.7%, bulging sigmoid sinus in 11.4% and 4.2%, carotid canal dehiscence in 0.8% and 1.3%, and aberrant internal carotid canal in 0 and 0.8%, respectively. Jugular bulb diverticulum (p = 0.01), bulging of the sigmoid sinus (p = 0.003), and MEV (p < 0.001) were more frequent in the CI candidates. ConclusionVascular canal variations are more common in the CI candidates and should be evaluated before CI surgery.

Noise reduction and image quality in ultra-high resolution computed tomography of the temporal bone using advanced modeled iterative reconstruction.

Background The novel advanced modeled iterative reconstruction (ADMIRE) algorithm in ultra-high-resolution (UHR) computed tomography (CT) of the temporal bone has not yet been systematically evaluated. Purpose To assess the potential of ADMIRE in temporal bone UHR CT. Material and Methods Forty-four patients who underwent UHR CT of the temporal bone using z-axis UHR protocol were retrospectively selected for analysis. Images were reconstructed using filtered back projection (FBP) and ADMIRE with multiple strength levels. Regions of interest were drawn in the posterior fossa and petrous bone. The average density (in Hounsfield units [HU]) and the image noise (standard deviation of density values) were extracted. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were then calculated. Additionally, a subjective qualitative analysis was performed using a five-point Likert scale. The potential dose reduction was extrapolated from objective analysis and confirmed in an additional phantom study. Results The image noise was significantly lower, and the SNR and CNR were significantly higher in ADMIRE reconstructions levels A2–A5 than in FBP ( P &lt; 0.001, respectively). Subjective image quality was significantly higher in ADMIRE levels A2–A5 than in FBP ( P &lt; 0.001) and it was rated best in ADMIRE level A3. Confirmed by the results from the phantom study, a dose reduction of at least 40% was feasible while maintaining image quality. Conclusions The ADMIRE reconstruction algorithm significantly improves image quality and reduces noise on temporal bone UHR CT scans. Thus, it allows for substantial dose reduction.