Learning curve for fusion magnetic resonance imaging targeted prostate biopsy and three-dimensional transrectal ultrasonography segmentation.

OBJECTIVE: To report the learning curve of multiple operators for fusion magnetic resonance imaging (MRI) targeted biopsy and to determine the number of cases needed to achieve proficiency. MATERIALS AND METHODS: All adult males who underwent fusion MRI targeted biopsy between February 2012 and July 2021 for clinically suspected prostate cancer (PCa) in a single centre were included. Fusion transrectal MRI targeted biopsy was performed under local anaesthesia using the Koelis platform. Learning curves for segmentation of transrectal ultrasonography (TRUS) images and the overall MRI targeted biopsy procedure were estimated with locally weighted scatterplot smoothing by computing each operator's timestamps for consecutive procedures. Non-risk-adjusted cumulative sum (CUSUM) methods were used to create learning curves for clinically significant (i.e., International Society of Urological Pathology grade ≥ 2) PCa detection. RESULTS: Overall, 1721 patients underwent MRI targeted biopsy in our centre during the study period. The median (interquartile range) times for TRUS segmentation and for the MRI targeted biopsy procedure were 4.5 (3.5, 6.0) min and 13.2 (10.6, 16.9) min, respectively. Among the 14 operators with experience of more than 50 cases, a plateau was reached after 40 cases for TRUS segmentation time and 50 cases for overall MRI targeted biopsy procedure time. CUSUM analysis showed that the learning curve for clinically significant PCa detection required 25 to 45 procedures to achieve clinical proficiency. Pain scores ranged between 0 and 1 for 84% of patients, and a plateau phase was reached after 20 to 100 cases. CONCLUSIONS: A minimum of 50 cases of MRI targeted biopsy are necessary to achieve clinical and technical proficiency and to reach reproducibility in terms of timing, clinically significant PCa detection, and pain.

3D-CEUS/MRI-CEUS fusion imaging vs 2D-CEUS after locoregional therapies for hepatocellular carcinoma: a multicenter prospective study of therapeutic response evaluation.

OBJECTIVES: To compare the diagnostic accuracy of 3D contrast-enhanced ultrasound (CEUS)/MRI-CEUS fusion imaging with 2D-CEUS in assessing the response of hepatocellular carcinoma (HCC) to locoregional therapies in a multicenter prospective study. MATERIALS AND METHODS: A consecutive series of patients with HCC scheduled for locoregional treatment were enrolled between April 2021 and March 2023. Patients were randomly divided into 3D-CEUS/MRI-CEUS fusion imaging group (3D/fusion group) or 2D-CEUS group (2D group). CEUS was performed 1 week before and 4-6 weeks after locoregional treatment. Contrast-enhanced MRI (CE-MRI) 4-6 weeks after treatment was set as the reference standard. CEUS images were evaluated for the presence or absence of viable tumors. Diagnostic performance criteria, including sensitivity, specificity, accuracy, and area under the curve (AUC), were determined for each modality. RESULTS: A total of 140 patients were included, 70 patients in the 2D group (mean age, 60.2 ± 10.4 years) and 70 patients in the 3D/fusion group (mean age, 59.8 ± 10.6 years). The sensitivity of the 3D/fusion group was 100.0% (95% CI: 75.9, 100.0), higher than that of the 2D group (55.6%, 95% CI: 22.7, 84.7; p = 0.019). The specificity of the 3D/fusion group was 96.3% (95% CI: 86.2, 99.4), which was comparable to that of the 2D group (98.4%, 95% CI: 90.0, 99.9; p = 0.915). The AUC of the 3D/fusion group was 0.98 (95% CI: 0.95, 1.00), higher than that of the 2D group (0.77, 95% CI: 0.56, 0.98; p = 0.020). CONCLUSION: 3D-CEUS/MRI-CEUS fusion imaging exhibits superior diagnostic accuracy in evaluating the treatment response to locoregional therapies for HCC. CLINICAL RELEVANCE STATEMENT: 3D-CEUS/MRI-CEUS fusion imaging can be applied for post-treatment assessment of residual tumors in HCC undergoing locoregional treatment, offering potential benefits in terms of accurate diagnosis and clinical management. KEY POINTS: Evaluating for HCC recurrence following locoregional therapy is important. 3D-CEUS/MRI-CEUS fusion imaging achieved a higher sensitivity than 2D-CEUS in assessing residual tumors after locoregional therapies. 3D-CEUS/MRI-CEUS fusion imaging can help clinicians intervene early in residual HCC lesions after locoregional treatment.

Multicenter and inter-software evaluation of ablative margins after thermal ablation of colorectal liver metastases.

PURPOSE: To assess the association between minimal ablative margin (MAM) and local tumor progression (LTP) following CT-guided thermal ablation of colorectal liver metastases (CRLM) in a multicenter cohort and across two confirmation software. MATERIALS AND METHODS: This multicenter retrospective study included patients who underwent CT-guided radiofrequency or microwave ablation for CRLM between 2009 and 2021 in three institutions. Three-dimensional (3D) MAM was retrospectively assessed using dedicated ablation confirmation software by automatic non-rigid (Ablation-fit) or semi-automatic rigid co-registration (SAFIR) of intraprocedural pre- and post-ablation contrast-enhanced CT scans by two independent reader teams blinded to patient outcomes. LTP was assessed on a per-tumor basis. Factors associated with LTP-free survival were assessed using multivariable Cox regression analysis. RESULTS: Overall, 113 patients (mean age: 67 ± 10 years; 78 men) who underwent thermal ablation for 189 CRLM (mean diameter: 1.9 ± 1.1 cm) met the inclusion criteria. 173/189 (92%) CRLM could be successfully analyzed using both software. Over a median follow-up of 31 months (IQR: 22-47), 21 of 173 CRLM (12.1%) developed LTP. On multivariable analysis, 3D MAM was independently associated with LTP in both software (Ablation-fit: HR 0.47, 95% CI: 0.36-0.61, p < 0.001; SAFIR: HR 0.42, 95% CI: 0.32-0.55, p < 0.001). No LTP was observed in CRLM ablated with MAM ≥ 4 mm (Ablation-fit) and ≥ 5 mm (SAFIR). The per-tumor median absolute difference in MAM quantification between both software was 2 mm (IQR: 1-3). CONCLUSION: MAM was independently associated with LTP after thermal ablation of CRLM across multicenter data and two confirmation software. Ablations achieving a MAM ≥ 5 mm were associated with local control in both software. CLINICAL RELEVANCE STATEMENT: MAMs from intraprocedural contrast-enhanced CT were independently associated with LTP after thermal ablation of CRLM across multicenter data and two confirmation software, with a margin ≥ 5 mm associated with local control in both software. KEY POINTS: Sufficient ablative margins are critical for local control following thermal ablation of CRLM. Intraprocedural CT-derived MAM was the only independent factor associated with LTP across two confirmation software. No LTP was observed in CRLM ablated with a MAM ≥ 5 mm.

Validation of a novel AI-based automated multimodal image registration of CBCT and intraoral scan aiding presurgical implant planning.

OBJECTIVES: The objective of this study is to assess accuracy, time-efficiency and consistency of a novel artificial intelligence (AI)-driven automated tool for cone-beam computed tomography (CBCT) and intraoral scan (IOS) registration compared with manual and semi-automated approaches. MATERIALS AND METHODS: A dataset of 31 intraoral scans (IOSs) and CBCT scans was used to validate automated IOS-CBCT registration (AR) when compared with manual (MR) and semi-automated registration (SR). CBCT scans were conducted by placing cotton rolls between the cheeks and teeth to facilitate gingival delineation. The time taken to perform multimodal registration was recorded in seconds. A qualitative analysis was carried out to assess the correspondence between hard and soft tissue anatomy on IOS and CBCT. In addition, a quantitative analysis was conducted by measuring median surface deviation (MSD) and root mean square (RMS) differences between registered IOSs. RESULTS: AR was the most time-efficient, taking 51.4 ± 17.2 s, compared with MR (840 ± 168.9 s) and SR approaches (274.7 ± 100.7 s). Both AR and SR resulted in significantly higher qualitative scores, favoring perfect IOS-CBCT registration, compared with MR (p = .001). Additionally, AR demonstrated significantly superior quantitative performance compared with SR, as indicated by low MSD (0.04 ± 0.07 mm) and RMS (0.19 ± 0.31 mm). In contrast, MR exhibited a significantly higher discrepancy compared with both AR (MSD = 0.13 ± 0.20 mm; RMS = 0.32 ± 0.14 mm) and SR (MSD = 0.11 ± 0.15 mm; RMS = 0.40 ± 0.30 mm). CONCLUSIONS: The novel AI-driven method provided an accurate, time-efficient, and consistent multimodal IOS-CBCT registration, encompassing both soft and hard tissues. This approach stands as a valuable alternative to manual and semi-automated registration approaches in the presurgical implant planning workflow.

Automated artificial intelligence-based three-dimensional comparison of orthodontic treatment outcomes with and without piezocision surgery.

OBJECTIVE(S): This study aims to evaluate the influence of the piezocision surgery in the orthodontic biomechanics, as well as in the magnitude and direction of tooth movement in the mandibular arch using novel artificial intelligence (AI)-automated tools. MATERIALS AND METHODS: Nineteen patients, who had piezocision performed in the lower arch at the beginning of treatment with the goal of accelerating tooth movement, were compared to 19 patients who did not receive piezocision. Cone beam computed tomography (CBCT) and intraoral scans (IOS) were acquired before and after orthodontic treatment. AI-automated dental tools were used to segment and locate landmarks in dental crowns from IOS and root canals from CBCT scans to quantify 3D tooth movement. Differences in mesial-distal, buccolingual, intrusion and extrusion linear movements, as well as tooth long axis angulation and rotation were compared. RESULTS: The treatment time for the control and experimental groups were 13.2 ± 5.06 and 13 ± 5.52 months respectively (P = .176). Overall, anterior and posterior tooth movement presented similar 3D linear and angular changes in the groups. The piezocision group demonstrated greater (P = .01) mesial long axis angulation of lower right first premolar (4.4 ± 6°) compared with control group (0.02 ± 4.9°), while the mesial rotation was significantly smaller (P = .008) in the experimental group (0.5 ± 7.8°) than in the control (8.5 ± 9.8°) considering the same tooth. CONCLUSION: The open source-automated dental tools facilitated the clinicians' assessment of piezocision treatment outcomes. The piezocision surgery prior to the orthodontic treatment did not decrease the treatment time and did not influence in the orthodontic biomechanics, leading to similar tooth movements compared to conventional treatment.

Can 3-dimensional cranial ultrasound be used to successfully reconstruct a 2-dimensional image without compromising on image quality in a neonatal population?

BACKGROUND: Cranial ultrasound is frequently performed in neonatal intensive care units and acquiring 2-dimensional (D) images requires significant training. Three-D ultrasound images can be acquired semi-automatically. OBJECTIVE: This proof-of-concept study aimed to demonstrate that 3-D study image quality compares well with 2-D. If this is successful, 3-D images could be acquired in remote areas and read remotely by experts. MATERIALS AND METHODS: This was a prospective study of 20 neonates, who underwent both routine 2-D and 3-D cranial ultrasounds. Images were reconstructed into standard views extracted from the 3-D volume and evaluated by three radiologists blinded to the acquisition method. The radiologists assessed for the presence of anatomical landmarks and overall image quality. RESULTS: More anatomical structures were identified in the 3-D studies (P<0.01). There was a trend that 3-D ultrasound demonstrated better image quality in the coronal plane, and 2-D in the sagittal plane, only reaching statistical significance for two coronal views and two sagittal views. CONCLUSION: Overall, this study has demonstrated that 3-D cranial ultrasound performs similarly to 2-D and could be implemented into neonatal practice.

Diagnostic utility of 3D MRI sequences in the assessment of central, recess and foraminal stenoses of the spine: a systematic review.

OBJECTIVE: To perform a systematic literature review on the diagnostic utility of 3D MRI sequences in the assessment of central canal, recess and foraminal stenosis in the spine. METHODS: The databases PubMed, MEDLINE (via OVID) and The Cochrane Central Register of Controlled Trials, were searched for studies that investigated the diagnostic use of 3D MRI to evaluate stenoses in various parts of the spine in humans. Three reviewers examined the literature and conducted systematic review according to PRISMA 2020 guidelines. RESULTS: Thirty studies were retrieved from 2 595 publications for this systematic review. The overall diagnostic performance of 3D MRI outperformed the conventional 2D MRI with reported sensitivities ranging from 79 to 100% and specificities ranging from 86 to 100% regarding the evaluation of central, recess and foraminal stenoses. In general, high level of agreement (both intra- and interrater) regarding visibility and pathology on 3D sequences was reported. Studies show that well-optimized 3D sequences allow the use of higher spatial resolution, similar scan time and increased SNR and CNR when compared to corresponding 2D sequences. However, the benefit of 3D sequences is in the additional information provided by them and in the possibility to save total protocol scan times. CONCLUSION: The literature on the spine 3D MRI assessment of stenoses is heterogeneous with varying MRI protocols and diagnostic results. However, the 3D sequences offer similar or superior detection of stenoses with high reliability. Especially, the advantage of 3D MRI seems to be the better evaluation of recess stenoses.

Comparison of prone and upright, stereotactic, and tomosynthesis-guided biopsies with secondary analysis of ultrasound-occult architectural distortions.

OBJECTIVES: Compare prone and upright, stereotactic, and tomosynthesis-guided vacuum-assisted breast biopsies (prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB) in a community-practice setting and review outcomes of ultrasound-occult architectural distortions (AD). METHODS: Consecutive biopsies performed at two community-based breast centers from 2016 to 2019 were retrospectively reviewed. Technical details of each procedure and patient outcomes were recorded. Separate analyses were performed for ultrasound-occult ADs. Two sample t-tests and Fisher's exact test facilitated comparisons. RESULTS: A total of 1133 patients underwent 369 prone DM-VABB, 324 prone DBT-VABB, 437 upright DM-VABB, and 123 upright DBT-VABB with 99.2%, 100%, 99.3%, and 99.2% success, respectively (p-values > 0.25). Mean lesion targeting times were greater for prone biopsy (minutes: 6.94 prone DM-VABB, 8.54 prone DBT-VABB, 5.52 upright DM-VABB, and 5.51 upright DBT-VABB; p-values < 0.001), yielding longer total prone procedure times for prone biopsy (p < 0.001). Compared to DM-VABB, DBT-VABB used fewer exposures (p < 0.001) and more commonly targeted AD, asymmetries, or masses (p < 0.001). Malignancy rates were similar between procedures: prone DM-VABB 22.4%, prone DBT-VABB 21.9%, upright DM-VABB 22.8%, and upright DBT-VABB 17.2% (p-values > 0.19). One hundred forty of the 1133 patients underwent 145 biopsies for ultrasound-occult AD (143 DBT-VABB and 2 DM-VABB). Biopsy yielded 27 malignancies and 47 high-risk lesions (74 of 145, 51%). Malignancy rate was 20.7% after surgical upgrade of one benign-discordant and two high-risk lesions. CONCLUSIONS: All biopsy procedure types were extremely successful. The 20.7% malignancy rate for ultrasound-occult AD confirms a management recommendation for tissue diagnosis. Upright biopsy was faster than prone biopsy, and DBT-VABB used fewer exposures than DM-VABB. CLINICAL RELEVANCE: Our results highlight important differences between prone DM-VABB, prone DBT-VABB, upright DM-VABB, and upright DBT-VABB. Moreover, the high likelihood of malignancy for ultrasound-occult AD will provide confidence in recommending tissue diagnosis in lieu of observation or clinical follow-up. KEY POINTS: • Upright and prone stereotactic and tomosynthesis-guided breast biopsies were safe and effective in the community-practice setting. • The malignancy rate for ultrasound-occult architectural distortion of 20.7% confirms the management recommendation for biopsy. • Upright procedures were faster than prone procedures, and tomosynthesis-guided biopsy used fewer exposures than stereotactic biopsy.

3D-validation of a simple tool to measure tibiofemoral axial rotation in tibial plateau fractures.

OBJECTIVES: Rotated tibial plateau fractures (TPF) frequently involve multiple planes of movement, yet current presurgical assessment methods do not account for tibiofemoral axial rotation. This study introduces and validates a simple tool to measure rotation-the Gerdy-Tibial-Tuberosity-Surgical-Epicondylar-Axis (GTT-SEA) angle. METHODS: Forty-seven preoperative 2D CT from a TPF database at a tertiary trauma center were retrieved, and 3D models reconstructed. Three observers made repeated 2D and 3D measurements of the GTT-SEA angle, spaced 4 weeks apart, for 20 patients. Inter- and intra-observer agreement and 2D-3D correlation were calculated. A reference angle was defined from non-operated patients, to classify 28 patients with MRI into neutral, external rotation, and internal rotation groups. The classification agreement and soft tissue involvement between groups were analyzed. RESULTS: Mean 2D GTT-SEA angle was 17.65 ± 2.36° in non-operated patients, and 13.86 ± 3.90° in operated patients. 3D GTT-SEA angle was 18.92 ± 4.53° in non-operated patients, and 14.76 ± 6.03° in operated patients. 2D-3D correlation was moderate to good (ICC 0.64 ~ 0.83). Two-dimensional (ICC 0.70) and 3D (ICC 0.55) inter-observer agreements were moderate; 2D (ICC 0.82 ~ 0.88) and 3D (ICC 0.76 ~ 0.95) intra-observer agreements were good to excellent. Rotation classification agreement was slight (kappa 0.17) for 2D and good (kappa 0.76) for 3D. More popliteofibular ligament injury was detected in rotated knees (p = 0.016). CONCLUSIONS: The GTT-SEA angle offers simple, accessible, yet reliable measurement of tibiofemoral axial rotation. Though a true reference range remains to be determined, this tool adds valuable information to existing TPF classifications, potentially allowing assessment of soft tissue involvement in TPF. CLINICAL RELEVANCE STATEMENT: The GTT-SEA angle will benefit patients who sustain tibial plateau fractures, by allowing physicians to more accurately measure and plan for the injury in 3D, and raising suspicion for otherwise undetected soft tissue injuries, which can impact operative outcomes. KEY POINTS: • Traumatic fractures of the tibial plateau may contain rotation-induced soft tissue injuries. • A new tool to measure axial rotation between the femur and tibia was found to have moderate to excellent inter- and intra-rater reliability. • The tool may have potential in predicting soft tissue injury and assisting with the decision to receive MRI.

Exploration of thoracoabdominal aortic mixed reality optimisation and its clinical application value in type A aortic dissection.

OBJECTIVES: This study aimed to explore the feasibility of low-dose computed tomography (CT)-based mixed reality and its clinical role in type A aortic dissection (TAAD) operations. METHODS: Eighty-seven patients diagnosed with TAAD were prospectively enrolled and underwent thoracoabdominal aorta mixed reality. They were randomly divided into a low-dose mixed reality group, a conventional mixed reality group and a conventional thoracoabdominal aorta computed tomography angiography (CTA) group. Three-dimensional modelling, mixed reality and CT reconstruction technology were selected. The radiation dose and image quality were compared using Student's t test. Doctors with different seniorities evaluated the clinical application value of thoracoabdominal aorta mixed reality using a Likert scale. The consistency was assessed using the Cohen kappa coefficient (k). The Pearson chi-square test was used to test the correlation of perioperative index results in TAAD operations. RESULTS: Low-dose CT technology can be effectively applied to thoracoabdominal aorta mixed reality and reduces the radiation dose by approximately 59% and the operation time and auxiliary cardiopulmonary bypass time by approximately 22% and 29%, respectively. The subjective scores of doctors with different seniorities on the clinical application value of thoracoabdominal aorta mixed reality were higher than those of thoracoabdominal aorta CTA (all p > 0.05). CONCLUSIONS: Low-dose CT can be effectively used in thoracoabdominal aortic mixed reality to reduce the radiation dose while ensuring quality. Low-dose thoracoabdominal aortic mixed reality has clinical application value and can effectively reduce the operation time and auxiliary cardiopulmonary bypass time in TAAD operations. KEY POINTS: • Low-dose CT technology can ensure the mixed reality quality of the thoracoabdominal aorta with a radiation dose reduction of approximately 59%. • Compared with thoracoabdominal aorta CTA, low-dose thoracoabdominal aorta mixed reality can reduce the operation time and auxiliary cardiopulmonary bypass time by approximately 20% and 29%, respectively, in TAAD operations. • The application value of low-dose thoracoabdominal aorta mixed reality in operation scheme formulation, operation risk assessment, operation navigation and diagnosis and treatment under safe distance was greater than that of thoracoabdominal aorta CTA in TAAD.

First experience of evaluation of the impact of high-matrix size reconstruction in image quality in arterial CT runoff studies of the lower extremities.

OBJECTIVES: To determine whether image reconstruction with a higher matrix size improves image quality for lower extremity CTA studies. METHODS: Raw data from 50 consecutive lower extremity CTA studies acquired on two MDCT scanners (SOMATOM Flash, Force) in patients evaluated for peripheral arterial disease (PAD) were retrospectively collected and reconstructed with standard (512 × 512) and higher resolution (768 × 768, 1024 × 1024) matrix sizes. Five blinded readers reviewed representative transverse images in randomized order (150 total). Readers graded image quality (0 (worst)-100 (best)) for vascular wall definition, image noise, and confidence in stenosis grading. Ten patients' stenosis scores on CTA images were compared to invasive angiography. Scores were compared using mixed effects linear regression. RESULTS: Reconstructions with 1024 × 1024 matrix were ranked significantly better for wall definition (mean score 72, 95% CI = 61-84), noise (74, CI = 59-88), and confidence (70, CI = 59-80) compared to 512 × 512 (wall = 65, CI = 53 × 77; noise = 67, CI = 52 × 81; confidence = 62, CI = 52 × 73; p = 0.003, p = 0.01, and p = 0.004, respectively). Compared to 512 × 512, the 768 × 768 and 1024 × 1024 matrix improved image quality in the tibial arteries (wall = 51 vs 57 and 59, p < 0.05; noise = 65 vs 69 and 68, p = 0.06; confidence = 48 vs 57 and 55, p < 0.05) to a greater degree than the femoral-popliteal arteries (wall = 78 vs 78 and 85; noise = 81 vs 81 and 84; confidence = 76 vs 77 and 81, all p > 0.05), though for the 10 patients with angiography accuracy of stenosis grading was not significantly different. Inter-reader agreement was moderate (rho = 0.5). CONCLUSION: Higher matrix reconstructions of 768 × 768 and 1024 × 1024 improved image quality and may enable more confident assessment of PAD. CLINICAL RELEVANCE STATEMENT: Higher matrix reconstructions of the vessels in the lower extremities can improve perceived image quality and reader confidence in making diagnostic decisions based on CTA imaging. KEY POINTS: • Higher than standard matrix sizes improve perceived image quality of the arteries in the lower extremities. • Image noise is not perceived as increased even at a matrix size of 1024 × 1024 pixels. • Gains from higher matrix reconstructions are higher in smaller, more distal tibial and peroneal vessels than in femoropopliteal vessels.

A learning curve in 3D virtual surgical planned orthognathic surgery.

OBJECTIVES: To assess the surgical accuracy of 3D virtual surgical planned orthognathic surgery and the influence of posterior impaction and magnitude of the planned movements on a possible learning curve. MATERIALS AND METHODS: This prospective cohort study included subjects who underwent bimaxillary surgery between 2016 and 2020 at the Department of Oral and Maxillofacial Surgery of the Radboud University Medical Center, Nijmegen. 3D virtual surgical planning (VSP) was performed with CBCT data and digitalized dentition data. By using voxel-based matching with pre- and postoperative CBCT data the maxillary movements were quantified in six degrees of freedom. The primary outcome variable, surgical accuracy, was defined as the difference between the planned and achieved maxillary movement. RESULTS: Based on 124 subjects, the surgical accuracy increased annually from 2016 to 2020 in terms of vertical translations (0.82 ± 0.28 mm; p = 0.038) and yaw rotations (0.68 ± 0.22°; p = 0.028). An increase in surgical accuracy was observed when combining all six degrees of freedom (p = 0.021) and specifically between 2016 and 2020 (p = 0.004). An unfavorable learning curve was seen with posterior impaction and with a greater magnitude of movements. CONCLUSION: The present study demonstrated a significant increase in surgical accuracy annually and therefore supports the presence of a learning curve. CLINICAL RELEVANCE: Cases with planned maxillary posterior impaction and/or a great magnitude of jaw movements should be transferred from the 3D VSP with extra care to obtain a satisfactory surgical accuracy.

Influence of age and diet consistency on the oral muscle pressure of orthodontically treated and untreated subjects with normal occlusion and comparison of their 3D facial shape.

OBJECTIVES: (1) To investigate the effect of age and diet consistency on maximum lips, tongue and cheek pressure of orthodontically treated and untreated subjects with normal, Class I dental occlusion, (2) to find out whether there is a muscle imbalance between anterior tongue and lip pressure in the same subjects at different ages and (3) to compare the 3D facial shape of treated and untreated individuals. MATERIAL AND METHODS: Subjects with normal occlusion were prospectively grouped into orthodontically treated/untreated and in children/adolescents/adults. Iowa Oral Performance Instrument was used to record the maximum muscle pressure. Two-way ANOVA and Tukey post hoc test analysed age-specific differences in muscle pressure. Two-way ANCOVA analysed the effect of diet consistency on muscle pressure. Lips and tongue imbalance was analysed using z-scores and 3D faces using a generalized Procrustes analysis. RESULTS: One hundred thirty-five orthodontically untreated and 114 treated participants were included. Muscle pressure was found to increase with age in both groups, except for the tongue in treated subjects. No differences in the balance between lips and tongue muscle pressure were found, but a higher cheek pressure in untreated adults (p<0.05) was observed. 3D facial shapes showed subtle differences. Untreated subjects with soft diet consistency showed lower lip pressure (p<0.05). CONCLUSION: Oral muscle pressure of orthodontically treated patients without relapse does not differ from that of untreated patients with Class-I occlusion. CLINICAL RELEVANCE: This study provides normative lip, tongue and cheek muscle pressure in subjects with normal occlusion, which can be used for diagnosis, treatment planning and stability.

Slim the face or not: 3D change of facial soft and hard tissues after third molars extraction: a pilot study.

BACKGROUND: Whether slim the face or not after removed third molars is the concern of some orthodontic treatment candidates. The aim of this article is to explore the volume changes of facial soft and hard tissues after third molars extraction, as well as develop a reproducible clinical protocol to precisely assess facial soft tissue volume change. METHODS: A non-randomized, non-blind, self-controlled pilot study was conducted. 24 adults aged 18-30 had ipsilateral third molars extracted. The body weight change was controlled within 2 kg. Structured light scans were taken under a standardized procedure pre-extraction (T0), three (T1), and six (T2) months post-extraction; CBCTs were taken at T0 and T2. The projection method was proposed to measure the soft tissue volume (STV) and the soft tissue volume change (STVC) by the Geomagic software. The hard tissue volume change (HTVC) was measured in the Dragonfly software. RESULTS: The final sample size is 23, including 5 males (age 26.6 ± 2.5 years) and 18 females (age 27.3 ± 2.5 years). The HTVC was - 2.33 ± 0.46ml on the extraction side. On the extraction side, the STV decreased by 1.396 (95% CI: 0.323-2.470) ml (P < 0.05) at T1, and increased by 1.753 (95% CI: -0.01-3.507) ml (P = 0.05) at T2. T2 and T0 had no difference (P > 0.05). The inter and intra-raters ICC of the projection method was 0.959 and 0.974. There was no correlation between the STVC and HTVC (P > 0.05). CONCLUSIONS: After ipsilateral wisdom teeth extraction, the volume of hard tissue on the extraction side reduces, and the volume of facial soft tissue does not change evidently. However, further research with large sample size is still needed. The STV measurement has excellent repeatability. It can be extended to other interested areas, including forehead, nose, paranasal, upper lip, lower lip and chin, which is meaningful in the field of orthodontics and orthopedics. TRIAL REGISTRATION: ChiCTR, ChiCTR1800018305 (11/09/2018), http://www.chictr.org.cn/showproj.aspx?proj=28868 .

[Automatic determination of mandibular landmarks based on three-dimensional mandibular average model].

OBJECTIVE: To explore an efficient and automatic method for determining the anatomical landmarks of three-dimensional(3D) mandibular data, and to preliminarily evaluate the performance of the method. METHODS: The CT data of 40 patients with normal craniofacial morphology were collected (among them, 30 cases were used to establish the 3D mandibular average model, and 10 cases were used as test datasets to validate the performance of this method in determining the mandibular landmarks), and the 3D mandibular data were reconstructed in Mimics software. Among the 40 cases of mandibular data after the 3D reconstruction, 30 cases that were more similar to the mean value of Chinese mandibular features were selected, and the size of the mandibular data of 30 cases was normalized based on the Procrustes analysis algorithm in MATLAB software. Then, in the Geomagic Wrap software, the 3D mandibular average shape model of the above 30 mandibular data was constructed. Through symmetry processing, curvature sampling, index marking and other processing procedures, a 3D mandible structured template with 18 996 semi-landmarks and 19 indexed mandibular anatomical landmarks were constructed. The open source non-rigid registration algorithm program Meshmonk was used to match the 3D mandible template constructed above with the tested patient's 3D mandible data through non-rigid deformation, and 19 anatomical landmark positions of the patient's 3D mandible data were obtained. The accuracy of the research method was evaluated by comparing the distance error of the landmarks manually marked by stomatological experts with the landmarks marked by the method of this research. RESULTS: The method of this study was applied to the data of 10 patients with normal mandibular morphology. The average distance error of 19 landmarks was 1.42 mm, of which the minimum errors were the apex of the coracoid process [right: (1.01±0.44) mm; left: (0.56±0.14) mm] and maximum errors were the anterior edge of the lowest point of anterior ramus [right: (2.52±0.95) mm; left: (2.57±1.10) mm], the average distance error of the midline landmarks was (1.15±0.60) mm, and the average distance error of the bilateral landmarks was (1.51±0.67) mm. CONCLUSION: The automatic determination method of 3D mandibular anatomical landmarks based on 3D mandibular average shape model and non-rigid registration algorithm established in this study can effectively improve the efficiency of automatic labeling of 3D mandibular data features. The automatic determination of anatomical landmarks can basically meet the needs of oral clinical applications, and the labeling effect of deformed mandible data needs to be further tested.

[Radiographic diagnosis of distal fibula avulsion fractures: Comparison of ankle X-ray and three-dimensional reconstruction of CT].

OBJECTIVE: To investigate the difference in sensitivity between X-ray and three-dimensional reconstruction of computed tomography (3D-CT) for the diagnosis of distal fibular avulsion fracture, and the radiographic presentation of the ossicle. METHODS: From January to October 2018, 92 patients with distal fibular avulsion fracture were visited for surgical treatment in Department of Sports Medicine, Peking University Third Hospital, and 60 cases were finally enrolled according to the inclusion and exclusion criteria. Intraoperative detection was regarded as the gold standard, and the diagnostic sensitivity of preoperative ankle X-ray and 3D-CT for the distal fibular avulsion fractures was statistically determined. The ossicle maximum diameter as well as the degree of its displacement were also measured. On 3D-CT, the distance from the ossicle center point to the anterior fibular tuberosity (a), the distance to the fibular tip (b), and the a/b value was used to present the ossicle displacement. RESULTS: Among the 60 patients, 36 and the 52 patients were correctly detected by X-ray and 3D-CT, respectively, and the sensitivities was 60.0% and 86.7%, respectively (P=0.004). The mean diameter of the ossicle on X-ray and 3D-CT was (9.2±3.9) mm and (10.5±3.2) mm, respectively. The mean distance from the ossicle center to the anterior fibular tuberosity (a) was (17.5±3.6) mm and the mean distance to the fibular tip (b) was (17.4±4.8) mm, with mean a/b values of 1.1±0.7. The intraclass correlation coefficients (ICC) for each measurement ranged from 0.891-0.998 with a high degree of consistency. CONCLUSION: Compared with X-ray, 3D-CT has higher sensitivity in diagnosing distal fibular avulsion fractures, can help clinicians evaluate ossicle's location and choose surgical methods, and is recommended to be performed in patients with suspected distal fibula avulsion fractures in clinical practice.

CT imaging-based approaches to cochlear duct length estimation-a human temporal bone study.

OBJECTIVES: Knowledge about cochlear duct length (CDL) may assist electrode choice in cochlear implantation (CI). However, no gold standard for clinical applicable estimation of CDL exists. The aim of this study is (1) to determine the most reliable radiological imaging method and imaging processing software for measuring CDL from clinical routine imaging and (2) to accurately predict the insertion depth of the CI electrode. METHODS: Twenty human temporal bones were examined using different sectional imaging techniques (high-resolution computed tomography [HRCT] and cone beam computed tomography [CBCT]). CDL was measured using three methods: length estimation using (1) a dedicated preclinical 3D reconstruction software, (2) the established A-value method, and (3) a clinically approved otosurgical planning software. Temporal bones were implanted with a 31.5-mm CI electrode and measurements were compared to a reference based on the CI electrode insertion angle measured by radiographs in Stenvers projection (CDLreference). RESULTS: A mean cochlear coverage of 74% (SD 7.4%) was found. The CDLreference showed significant differences to each other method (p < 0.001). The strongest correlation to the CDLreference was found for the otosurgical planning software-based method obtained from HRCT (CDLSW-HRCT; r = 0.87, p < 0.001) and from CBCT (CDLSW-CBCT; r = 0.76, p < 0.001). Overall, CDL was underestimated by each applied method. The inter-rater reliability was fair for the CDL estimation based on 3D reconstruction from CBCT (CDL3D-CBCT; intra-class correlation coefficient [ICC] = 0.43), good for CDL estimation based on 3D reconstruction from HRCT (CDL3D-HRCT; ICC = 0.71), poor for CDL estimation based on the A-value method from HRCT (CDLA-HRCT; ICC = 0.29), and excellent for CDL estimation based on the A-value method from CBCT (CDLA-CBCT; ICC = 0.87) as well as for the CDLSW-HRCT (ICC = 0.94), CDLSW-CBCT (ICC = 0.94) and CDLreference (ICC = 0.87). CONCLUSIONS: All approaches would have led to an electrode choice of rather too short electrodes. Concerning treatment decisions based on CDL measurements, the otosurgical planning software-based method has to be recommended. The best inter-rater reliability was found for CDLA-CBCT, for CDLSW-HRCT, for CDLSW-CBCT, and for CDLreference. KEY POINTS: • Clinically applicable calculations using high-resolution CT and cone beam CT underestimate the cochlear size. • Ten percent of cochlear duct length need to be added to current calculations in order to predict the postoperative CI electrode position. • The clinically approved otosurgical planning software-based method software is the most suitable to estimate the cochlear duct length and shows an excellent inter-rater reliability.

Comparison of CAIPIRINHA-accelerated 3D fat-saturated-SPACE MRI with 2D MRI sequences for the assessment of shoulder pathology.

OBJECTIVES: To compare the performance of 6-min MRI with a fat-saturated 3D-controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) Sampling perfection with application-optimized contrast using different flip angle evolution (SPACE) TSE protocol with 10-min 2D TSE MRI protocol for assessment of abnormalities of the shoulder. METHODS: Forty-nine subjects underwent both 3D fat-saturated-CAIPIRINHA SPACE and 2D TSE sequences of the shoulder on a 3.0-T system. Following randomization and anonymization, two musculoskeletal radiologists evaluated the 2D and 3D images independently for image quality and diagnostic capability. Descriptive statistics, inter-observer, and inter-method concordance were investigated. p values < 0.05 were considered significant. RESULTS: For image quality assessment, 2D images were similar to 3D CAIPIRINHA SPACE images (p = 0.05). 3D had lower noise standard deviation (SD) and higher fluid CNR than 2D images (p = 0.00). For diagnostic capability assessment, using 2D TSE as a standard of reference, sensitivity, specificity, and accuracy of 3D SPACE were, respectively, 94.81%, 94.12%, and 94.39% for tendon abnormalities; 97.06%, 80.00%, and 91.84% for acromioclavicular joint abnormalities; 88.89%, 100.00%, and 93.89% for adjacent bone alterations; and 97.30%, 100%, and 97.96% for joint fluid/effusion assessment. The inter-method concordance was moderate to almost perfect. The inter-observer-concordance of the shoulder assessment was also moderate to almost perfect, with SSP lesions demonstrating the greatest concordance. CONCLUSIONS: The performance of 6-min 3D fat-saturated-CAIPIRINHA SPACE MRI for shoulder MRI is similar to that of 10-min 2D TSE MRI. 3D fat-saturated-CAIPIRINHA SPACE MRI can be utilized to reduce scan time without degradation in image quality. KEY POINTS: • CAIPIRINHA acceleration 3D fat-saturated-MRI of the shoulder is achievable in 6 min with high spatial resolution. • 3D fat-saturated CAIPIRINHA MRI is similar to 2D MRI in the shoulder assessment. • 3D CAIPIRINHA MRI images enable rapid diagnosis of shoulder abnormalities without image quality degradation.

3D CAIPIRINHA SPACE versus standard 2D TSE for routine knee MRI: a large-scale interchangeability study.

OBJECTIVE: To perform a large-scale interchangeability study comparing 3D controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) sampling perfection with application optimized contrast using different flip angle evolutions (SPACE) TSE with standard 2D TSE for knee MRI. METHODS: In this prospective study, 250 patients underwent 3 T knee MRI, including a multicontrast 3D CAIPIRINHA SPACE TSE (9:26 min) and a standard 2D TSE protocol (12:14 min). Thirty-three (13%) patients had previous anterior cruciate ligament and/or meniscus surgery. Two radiologists assessed MRIs for image quality and identified pathologies of menisci, ligaments, and cartilage by using a 4-point Likert scale according to the level of diagnostic confidence. Interchangeability of the protocols was tested under the same-reader scenario using a bootstrap percentile confidence interval. Interreader reliability and intermethod concordance were also evaluated. RESULTS: Despite higher image quality and diagnostic confidence for standard 2D TSE compared to 3D CAIPIRINHA SPACE TSE, the protocols were found interchangeable for diagnosing knee abnormalities, except for patellar (6.8% difference; 95% CI: 4.0, 9.6) and trochlear (3.6% difference; 95% CI: 0.8, 6.6) cartilage defects. The interreader reliability was substantial to almost perfect for 2D and 3D MRI (range κ, 0.785-1 and κ, 0.725-0.964, respectively). Intermethod concordance was almost perfect for all diagnoses (range κ, 0.817-0.986). CONCLUSION: Multicontrast 3D CAIPIRINHA SPACE TSE and standard 2D TSE protocols perform interchangeably for diagnosing knee abnormalities, except for patellofemoral cartilage defects. Despite the radiologist's preference for 2D TSE imaging, a pursuit towards time-saving 3D TSE knee MRI is justified for routine practice. KEY POINTS: • Multicontrast 3D CAIPIRINHA SPACE and standard 2D TSE protocols perform interchangeably for diagnosing knee abnormalities, except for patellofemoral cartilage defects. • Radiologists are more confident in diagnosing knee abnormalities on 2D TSE than on 3D CAIPIRINHA SPACE TSE MRI. • Despite the radiologist's preference for 2D TSE, a pursuit towards accelerated 3D TSE knee MRI is justified for routine practice.

Assessment of hepatic arterial hemodynamics with 4D flow MRI: in vitro analysis of motion and spatial resolution related error and in vivo feasibility study in 20 volunteers.

OBJECTIVES: To assess the ability of four-dimensional (4D) flow MRI to measure hepatic arterial hemodynamics by determining the effects of spatial resolution and respiratory motion suppression in vitro and its applicability in vivo with comparison to two-dimensional (2D) phase-contrast MRI. METHODS: A dynamic hepatic artery phantom and 20 consecutive volunteers were scanned. The accuracies of Cartesian 4D flow sequences with k-space reordering and navigator gating at four spatial resolutions (0.5- to 1-mm isotropic) and navigator acceptance windows (± 8 to ± 2 mm) and one 2D phase-contrast sequence (0.5-mm in -plane) were assessed in vitro at 3 T. Two sequences centered on gastroduodenal and hepatic artery branches were assessed in vivo for intra - and interobserver agreement and compared to 2D phase-contrast. RESULTS: In vitro, higher spatial resolution led to a greater decrease in error than narrower navigator window (30.5 to -4.67% vs -6.64 to -4.67% for flow). In vivo, hepatic and gastroduodenal arteries were more often visualized with the higher resolution sequence (90 vs 71%). Despite similar interobserver agreement (κ = 0.660 and 0.704), the higher resolution sequence had lower variability for area (CV = 20.04 vs 30.67%), flow (CV = 34.92 vs 51.99%), and average velocity (CV = 26.47 vs 44.76%). 4D flow had lower differences between inflow and outflow at the hepatic artery bifurcation (11.03 ± 5.05% and 15.69 ± 6.14%) than 2D phase-contrast (28.77 ± 21.01%). CONCLUSION: High-resolution 4D flow can assess hepatic artery anatomy and hemodynamics with improved accuracy, greater vessel visibility, better interobserver reliability, and internal consistency. KEY POINTS: • Motion-suppressed Cartesian four-dimensional (4D) flow MRI with higher spatial resolution provides more accurate measurements even when accepted respiratory motion exceeds voxel size. • 4D flow MRI with higher spatial resolution provides substantial interobserver agreement for visualization of hepatic artery branches. • Lower peak and average velocities and a trend toward better internal consistency were observed with 4D flow MRI as compared to 2D phase-contrast.