Three-dimensional Imaging Software Research Articles

Assessing the Accuracy of Linear Alveolar Bone Measurements for Implant Planning Using Cone-Beam Computed Tomography by Comparing Three Competent Three-Dimensional Imaging Software: An In Vitro Study.

This study aims to assess the accuracy of linear alveolar bone measurements for implant planning using cone-beam computed tomography (CBCT) by comparing three 3D imaging software: CareStream (Carestream Health, Rochester, New York, United States), RadiAnt (Medixant, Poznan, Poland), and iRYS (Cefla s.c., Imola, Italy). Twenty-seven dry goat mandibles were used for this in-vitro study. Gutta-percha markers were placed on the mandibles, which were then scanned using a CBCT machine. Linear measurements of the alveolar bone were taken at the implant sites using CareStream, RadiAnt, and iRYS software, and compared to gold-standard measurements obtained using digital Vernier calipers. Measurements included bone height and width, and the absolute measurement errors were calculated to assess accuracy. iRYS consistently provided the most accurate measurements compared to the control, especially at lower error thresholds. RadiAnt tended to overestimate, while CareStream yielded intermediate values. Across all thresholds, iRYS showed the least deviation, followed by CareStream and RadiAnt. Statistical analysis showed no significant differences between the three software programs at higher error thresholds, confirming the reliability of each for implant planning. All three software programs (iRYS, CareStream, and RadiAnt) offered reliable and accurate measurements for implant planning using CBCT, with iRYS being the most accurate. Clinicians can confidently use any of the three, although iRYS may be preferred for cases requiring higher precision.

Evaluation of Soft Tissue Changes Following Orthognathic Surgery Using Virtual Surgical Planning Software.

Orthognathic surgery brings about a harmonious relationship between jaws, resulting in improved facial aesthetics. It is key to analyze if satisfactory results can be attained by using virtual surgical planning for orthognathic procedures so as to recommend it for routine clinical practice. The aims of this study were to evaluate the various soft tissue changes that take place following orthognathic surgery using three-dimensional (3D) imaging and virtual surgical planning software and quantify the accuracy of virtual surgical planning software on patients undergoing orthognathic surgery. This is an observational prospective study with a sample size of 12. In this prospective study, 12 patients undergoing orthognathic surgery were included following the inclusion and exclusion criteria. A usual pre-surgical work-up was done and a 3D replica of the facial skeleton was formulated using the software with the DICOM data acquired from the patient i.e., CT and scans of patient's dentition. Virtual surgical planning was done and splints were manufactured according to the desired newly achieved position. Patients were operated following the virtual surgical plan guided by the computer-aided design and computer-aided manufacturing (CAD-CAM) splints. Post-operative evaluation was done. As the study is more of a descriptive study to obtain detailed knowledge of a new procedure, only one group is being studied and hence there is no statistical testing included in this study. The mean discrepancy noticed after superimposition of soft tissue points was 0.92 with a standard deviation of 0.3. 3D CT virtual surgical planning is a reliable tool to achieve predictable and reliable post-operative results in orthognathic surgical cases.

Morphological and quantitative study of the inferior alveolar nerve canal in hemifacial microsomia.

This study aimed to probe into the anatomic course of inferior alveolar nerve canal (IANC) in hemifacial microsomia (HFM) on a large scale, morphological observations and further quantitative study were performed. Patients were classified by Pruzansky-Kaban classification. The anatomic course of IANC was analyzed morphologically with three-dimensional (3D) imaging software among 248 patients. Seven distances between fixed landmarks on both sides were measured for 236 patients. The differences between affected and unaffected sides were compared. Significant differences were found in the entrance (P < 0.001), route (P < 0.001), and exit (P < 0.05) of IANC in type IIb and III HFM. The higher the degree of mandibular deformity was, the higher the incidence of IANC variation was (P < 0.05). The distances in the horizontal aspect of IANC including from mandibular foramen to mental foramen (P < 0.05) and from mental foramen to gonion (P < 0.05) were significantly shorter on the affected side. Abnormalities of the anatomical course of IANC exist in patients with Pruzansky-Kaban type IIb and type III HFM. The reduction of IANC on the affected side in the horizontal distance is more obvious. Three-dimensional imaging assessment is recommended before surgery.

Three-Dimensional Assessment of the Pharyngeal Airway in Growing versus Non-Growing Subjects with/without Cleft Lip and Palate

Clefts of the lip or palate (CLPs) are the most common craniofacial birth defect, with a worldwide incidence of ~1 in 700 live births. The objective of this study is to assess the characteristics of the nasopharyngeal airway in growing vs. non-growing cleft lip/palate subjects and compare them with normal subjects. This retrospective study analyzed eighty-seven scans of three groups from cone beam computed tomography (CBCT). The cone beam computed tomography (CBCT) scans were coded and landmarks were identified using a Dolphin three-dimensional (3D) imaging software server (version 11.7; Patterson Dental Supply, Chatsworth, Calif). All values showed strong measurement reliability (&gt;80), except for the nasopharynx measurement. Regarding gender difference, for the nasopharynx, female subjects (1261.32 ± 713.94) showed the lowest significant values in non-growing unilateral compared to males (6496.8 ± 2987) at p = 0.008. For oropharynx, in the growing bilateral cleft group, male subjects (13,046.79 ± 5521.89) showed a significant difference (p = 0.046) compared to females (8468.98 ± 4279.99). MP-SN, B, A, SNA., SN.B., and ANS-ME showed significant differences for cephalometric parameters (p &lt; 0.05). Despite significant differences in linear and angular measurements, volumetric airway measurements showed no significant differences in the growing groups. For non-growing cleft subjects, the cleft anomaly significantly affected the nasal cavity and left maxillary sinus volumes.

Evaluation of the influence of hyoid bone position, volume, and types on pharyngeal airway volume and cephalometric measurements.

We aimed to explore the position, morphological, and morphometric properties of the hyoid bone (HB) and to investigate the effect of HB on the pharyngeal airway (PA) volume and cephalometric measurements. A total of 305 patients with CT images were included in the study. DICOM images were transferred to the InVivoDental three-dimensional imaging software. The position of the HB was determined based on the cervical vertebra level and in volume render tab, the bone was classified into six types after all structures around the HB were removed. Also, final bone volume was recorded. In the same tab, the pharyngeal airway volume was divided and measured in three groups (nasopharynx-oropharynx-hypopharynx). The linear and angular measurements were performed on the 3D cephalometric analysis tab. HB was most commonly located in C3 vertebra level (80.3%). While B-type was found to be the most frequent (34%), V-type was the least frequent (8%). The volume of the HB was found to be significantly higher in male (3205 mm3) than female (2606 mm3) patients. Also, it was significantly higher in the C4 vertebra group. The vertical height of the face was positively correlated with the HB volume, C4 level position, and increased oro-nasopharyngeal airway volume. The volume of the HB is found to differ significantly between genders and can potentially serve as a valuable diagnostic tool for understanding respiratory disorders. Its morphometric features are associated with increased face height and airway volume; however, are not related with the skeletal malocclusion classes.

Impact of tumor contact surface area on collecting system entry in robot-assisted partial nephrectomy: a retrospective analysis

BackgroundCollecting system entry in robot-assisted partial nephrectomy may occur even in cases showing a low N factor in the R.E.N.A.L nephrometry score. Therefore, in this study, we focused on the tumor contact surface area with the adjacent renal parenchyma and attempted to construct a novel predictive model for collecting system entry.MethodsAmong 190 patients who underwent robot-assisted partial nephrectomy at our institution from 2015 to 2021, 94 patients with a low N factor (1–2) were analyzed. Contact surface was measured with three-dimensional imaging software and defined as the C factor, classified as C1, < 10 cm [2]; C2, ≥ 10 and < 15 cm [2]; and C3: ≥ 15 cm [2]. Additionally, a modified R factor (mR) was classified as mR1, < 20 mm; mR2, ≥ 20 and < 40 mm; and mR3, ≥ 40 mm. We discussed the factors influencing collecting system entry, including the C factor, and created a novel collecting system entry predictive model.ResultsCollecting system entry was observed in 32 patients with a low N factor (34%). The C factor was the only independent predictive factor for collecting system entry in multivariate regression analysis (odds ratio: 4.195, 95% CI: 2.160–8.146, p < 0.0001). Models including the C factor showed better discriminative power than the models without the C factor.ConclusionsThe new predictive model, including the C factor in N1-2 cases, may be beneficial, considering its indication for preoperative ureteral catheter placement in patients undergoing robot-assisted partial nephrectomy.

Promising results of an non-invasive measurement of knee implant loosening using a loading device, CT-scans and 3D image analysis

BackgroundAfter total knee arthroplasty up to 13% requires revision surgery to address loosening. No current diagnostic modalities have a sensitivity or specificity higher than 70–80% to detect loosening, leading to 20–30% of patients undergoing unnecessary, risky and expensive revision surgery. A reliable imaging modality is required to diagnose loosening. This study presents a new and non-invasive method and evaluates its reproducibility and reliability in a cadaveric study. MethodsTen cadaveric specimens were implanted with a loosely fitted tibial components and CT scanned under load towards valgus and varus using a loading device. Advanced three-dimensional imaging software was used to quantify displacement. Subsequently, the implants were fixed to the bone and scanned to determine the differences between the fixed and the loose state. Reproducibility errors were quantified using a frozen specimen in which displacement was absent. FindingsReproducibility errors, expressed as mean target registration error, screw-axis rotation and maximum total point motion were 0.073 mm (SD 0.033), 0.129 degrees (SD 0.039) and 0.116 mm (SD 0.031), respectively. In the loose condition, all displacements and rotation changes were larger than the reported reproducibility errors. Comparing the mean target registration error, screw axis rotation and maximum total point motion in the loose condition to the fixed condition resulted in mean differences of 0.463 mm (SD 0.279; p = 0.001), 1.769 degrees (SD 0.868; p < 0.001) and 1.339 mm (SD 0.712; p < 0.001), respectively. InterpretationThe results of this cadaveric study show that this non-invasive method is reproducible and reliable for detection of displacement differences between fixed and loose tibial components.

Wear and Color Stability of Preheated Bulk-fill and Conventional Resin Composites.

Bulk-fill resin composite is commonly used in direct restorations. It is recommended that the high-viscosity version of these materials be preheated to improve flowability and adaptability. It is unknown what effects preheating (PH) might have on the wear resistance and color stability of these resin composites. This study compared the wear and color stability of high-viscosity bulk-fill and conventional resin composites with and without PH, using the CIEDE2000 formula. Thirty-two disc-shaped specimens (n=16, 10×3 mm) were prepared with Filtek One Bulk Fill Restorative (FOBFR; 3M ESPE) and Filtek Supreme Ultra (FSU, 3M ESPE) to determine wear. Each group was divided into subgroups based on preparation conditions, that is, PH and room temperature (RT) (n=8). Thermomechanical fatigue was applied to specimens, and volumetric material loss was calculated using a laser scanner (LAS-20, SD Mechatronik, Feldkirchen-Westerham, Germany) and three-dimensional imaging software (Geomagic, 3D Systems, Rock Hill, SC, USA). An additional 124 disc-shaped specimens (n=64, 10×1 mm) were prepared with FOBFR and FSU, and subgroups were formed based on preparation conditions (PH and RT, n=32). Specimens were aged for 14 days in coffee, grape juice, distilled water, and thermocycling (20,000 cycles, 5°C-55°C). To determine color change, the lightness (L), chroma (C), and hue (H) values were measured at baseline and after 14 days using the CIEDE2000 formula. All data were statistically analyzed, and a 95% significance level was set. In both the PH and RT groups, FSU exhibited greater wear than FOBFR (p<0.05). Both materials were subjected to increased wear as a result of PH. After aging, a significant difference in color change was observed (p<0.05) when controlling for time and resin composite type, except for deionized water and thermocycling (p>0.05). PH had no effect on the color stability of the resin composite at any time (p<0.05). The high-viscosity bulk-fill resin composite displayed superior wear resistance and similar color stability compared with its conventional counterpart. PH resin composite may increase its susceptibility to wear and has no effect on its color stability.

User of angiotensin-converting-enzyme inhibitor and/or angiotensin II receptor blocker might be associated with vascular calcification in predialysis chronic kidney disease patients: a retrospective single-center observational study

BackgroundVascular calcification is a prominent feature in chronic kidney disease (CKD) and diabetes mellitus. A recent report suggests that angiotensin II is protective to vascular calcification. Therefore, we investigated the relationship between vascular calcification and use of angiotensin-converting-enzyme inhibitor (ACEI) and/or angiotensin II receptor blocker (ARB) from a cross-sectional view.MethodsA total of 121 predialysis CKD patients (age 71 ± 12 y; male 72; estimated glomerular filtration rate (eGFR) 20.2 (11.8 - 40.3) mL/min/1.73 m2) who underwent thoracoabdominal plain computed tomography scan were included in this study. The total vascular calcification volume (Calc) was calculated with a three-dimensional imaging software and standardized by body surface area (BSA). The relevance between log [Calc/BSA] and ACEI/ARB use was investigated by multivariate linear regression analyses with or without a time-duration factor of ACEI/ARB use.ResultsThe Calc/BSA was 5.62 (2.01 - 12.7) mL/m2 in 121 patients. In multivariate analyses adjusted with age, sex, ACEI/ARB and log [eGFR], ACEI/ARB use is significantly and positively associated with log [Calc/BSA] (β = 0.2781, p = 0.0007). Even after the adjustment by age, sex, log [eGFR], phosphate, diabetes mellitus, systolic blood pressure, warfarin, hypertension, dyslipidemia, low-density lipoprotein cholesterol, diuretics and ACEI/ARB, ACEI/ARB use is significantly and positively associated with log [Calc/BSA] (β = 0.1677, p = 0.0487). When 90 patients whose time-duration of ACEI/ARB use was clear in medical records were studied, a multivariate analysis adjusted with age, sex, log [eGFR], and ACEI/ARB duration factors showed that the longer use of ACEI/ARB more than 2 years was significantly, independently and positively associated with log [Calc/BSA] (β = 0.2864, p = 0.0060).ConclusionsACEI/ARB user was associated with vascular calcification in predialysis patients with low eGFR. Prospective studies with larger numbers of patients or more in vitro studies are needed to confirm whether this phenomenon is due to the use of ACEI/ARB itself, the underlying disease condition or the prescription bias.

Three-dimensional measurement of radiographic bone–implant contact lengths of zygomatic implants in zygomatic bone: a retrospective study of 66 implants in 28 patients

Zygomatic implant treatment is widely applied for severe maxillary atrophy to help rehabilitate the maxillary dentition. This retrospective study was performed to evaluate the actual radiographic bone–implant contact (rBIC) lengths of zygomatic implants. The records of 28 patients who underwent zygomatic implant surgery and subsequent follow-up examinations between August 2013 and September 2018 in the Department of Oral and Maxillofacial Surgery, Taipei Tzu Chi Hospital were reviewed. The surgeries were performed by a single surgeon using the same treatment protocol. All patients had a computed tomography scan at 1year after the surgery. Using three-dimensional imaging software, an investigator measured the rBIC lengths of 66 implants and documented their clinical status. The implant survival rate was 100%. The mean rBIC length was significantly longer in male patients than in female patients (20.80±5.88mm versus 17.79±6.34mm; P=0.028). The mean rBIC length of double zygomatic implants was significantly longer when compared to that of single implants (21.11±6.23mm versus 17.75±5.85mm; P=0.027). This article is novel in reporting the exact rBIC lengths of zygomatic implants in a clinical setting. The results showed that zygomatic implants are a viable treatment modality for full-mouth rehabilitation.

Stress distribution of cementless stems with unique flanges in a rectangular cross-section: thermoelastic stress imaging study.

Objective: In this study, thermoelastic stress analysis was conducted to clarify the surface stress distribution of a femur in which a BiCONTACT E stem was inserted. The contact sites between the stem and femur were examined to investigate the association with the range of stress distribution.Materials and Methods: BiCONTACT E was set up using two synthetic femurs that mimic the morphology and mechanical properties of living bone. Preoperative planning was performed using three-dimensional imaging software. The synthetic bone was placed in a sample holder. After the stem was implanted into the synthetic bone, computed tomography imaging was performed. The contact sites between the stem and the cortical part of the synthetic bone were examined using the imaging software. Subsequently, thermoelastic stress measurements were performed on the sample.Results: The results of thermoelastic stress analysis indicated a minimum change in the sum of principal stresses [Δ (σ1+σ2)] on the medial side and a maximum change in the sum of principal stresses on the lateral side. Thus, no minimum change was observed in the sum of the principal stresses at the maximum proximal part. It is reasonable to assume that the use of a cementless stem can inevitably lead to bone atrophy in the proximal part of the femur. The contact sites between the stem and femur were also investigated, and the results of the study clearly and quantitatively demonstrated the correlation of the contact sites with a range of stress distributions.Conclusion: The surface stress distribution of a femur, in which a BiCONTACT E stem was inserted, was clarified. The contact sites between the stem and femur were also investigated. Furthermore, the correlation between these results and clinical bone response was investigated in this study.

The Characteristics of the Favard E4 Glenoid Morphology in Cuff Tear Arthropathy: A CT Study.

Background: Cuff tear arthropathy (CTA) is characterized by superior migration of the humeral head with superior erosion of the glenoid. Rarely, humeral head migration can be anteroinferior with associated anterior erosion of the glenoid, a pattern described by Favard as the type E4 glenoid. The purpose of this retrospective imaging study was to analyze the 2D and 3D characteristics of the E4 glenoid. Methods: A shoulder arthroplasty database of 258 cuff tear arthropathies was examined to identify patients with an E4 type deformity. This resulted in a study cohort of 15 females and 2 males with an average age of 75 years. All patients had radiographs and CT scans available for analysis. CT-scan DICOM (Digital Imaging and Communications in Medicine) data were uploaded to a validated three-dimensional (3D) imaging software. Muscle fatty infiltration, glenoid measurements (anteversion, inclination), and humeral head subluxation according to the scapular plane were determined. Results: The mean anteversion and inclination of the E4 cohort were 32° ± 14° and −5° ± 2, respectively. The mean anterior subluxation was 19% ± 16%. All cases had severe grade 3 or 4 fatty infiltration of the infraspinatus, whereas only 65% had grade 3 or 4 subscapularis fatty infiltration. A significant correlation existed between glenoid anteversion and humeral head subluxation (p < 0.001), but no correlation was found with muscle fatty infiltration. The CT analysis demonstrated an acquired erosive biconcave morphology in 11 patients (65%) and monoconcavity in 6 patients (35%). Conclusion: The E4 type glenoid deformity in cuff tear arthropathy is characterized by an anterior erosion and anteversion associated with anterior subluxation of the humeral head.

Comparative Reliability Assessment of Tooth Volume Measurement with Different Three-Dimensional Imaging Software

Objective. To evaluate the in vivo tooth volume through VRMesh and 3Matic programs and to compare the measurements to the physical volume. So, the aim of the study was to ensure the reliability and sensitivity of the three-dimensional software (VRMesh and 3Matic) in measuring tooth volume. Material and Methods. The volume of 26 extracted upper first premolars from orthodontic patients who had CBCT before orthodontic treatment were measured. Two different commercial programs, which were VRMesh and 3Matic, were used to calculate the volume of the segmented upper first premolar from CBCT. The in vivo tooth volume was compared to the physical tooth volume to examine the accuracy of the two software in measuring the tooth volume. Results. The difference between the mean of the in vivo and in vitro tooth volume measurements was too small, making it clinically nonsignificant. ANOVA test was used as a statistical tool, and no statistically significant difference was noticed among the measurements. The values were normally distributed when tested for normality by Kolmogorov-Smirnov and Shapiro-Wilk test. P value less than or equal to 0.05 ( P ≤ 0.05 ) was considered statistically significant. Conclusion. The assessment of the in vivo tooth volume measurement with different three-dimensional imaging software (VRMesh and 3Matic) programs in comparison with the tooth physical volume is reliable. The use of a mouse pen during the refining stage of the segmentation may have increased the accuracy of the procedure. The determined in vivo tooth volumes are dependable and can be applied in orthodontic diagnosis and treatment planning.

Three-dimensional evaluation of perirenal fat volume in patients with nephrolithiasis.

The concept of adipose tissue as an organ unto itself represents a new medical construct; already differences in the volume of perirenal fat around a tumor-bearing kidney have been described. We hypothesized that renal calculi may have similar impact on perirenal fat or alternatively abnormalities in urinary metabolites may be the result of perirenal fat affecting renal metabolism and subsequent stone formation. Accordingly, we conducted a study utilizing three-dimensional imaging software to evaluate perirenal fat volume (PFV) in patients with nephrolithiasis. Among 40 patients with a history of unilateral nephrolithiasis who underwent percutaneous nephrolithotomy between 2010 and 2016, the following data were acquired: body mass index, past medical history, stone characteristics and composition (i.e., calcium oxalate, calcium phosphate, uric acid, and struvite calculi). In addition, patients were stratified by dominant stone composition (≥ 50% fraction). Bilateral PFV measurements were obtained using the preoperative computed tomography scan and specialized three-dimensional imaging software. The PFV of stone-bearing kidneys was significantly greater than non-stone-bearing kidneys (397.3 and 323cc, respectively; p = 0.004), with the PFV difference in patients with CO-dominant stone-bearing kidneys reaching statistical significance (p = 0.003). Subgroup analysis showed greater PFV surrounding the stone-bearing kidney irrespective of gender (p = 0.03), with male patients possessing significantly greater stone-bearing (p = 0.01) and bilateral PFV (p = 0.01) compared to females. No significant correlations were found between PFV and stone volume or stone density. The PFV of calcium oxalate stone-bearing kidneys is significantly greater than non-stone-bearing kidneys for both male and female patients with nephrolithiasis.

A Novel Method to Calculate the Volume of Alveolar Cleft Defect Before Surgery.

This study aimed to evaluate a novel subtractive method for the precise calculation of alveolar cleft defect volume before surgery using the three-dimensional imaging software Mimics. Ten patients (3 female, 7 male, age range 8-12 years) with unilateral alveolar cleft were enrolled in the study. Preoperative helical computed tomography scans were performed for all patients. A new subtractive method was introduced to precisely calculate the alveolar cleft defect volume before surgery with the aid of Mimics. The DICOM data of every patient were processed using the subtractive method. Statistical analyses were performed using Pearson's correlation test and t test. The mean volume of the alveolar cleft defect was 1811.97 ± 817.90 mm. The mean time spent to calculate an alveolar cleft defect volume was 60.60 ± 11.67 minutes. The Pearson correlation test (r = 0.38, P = 0.279) indicated a poor correlation between alveolar cleft defect volume and calculation time. Preoperative knowledge of defect volume is crucial in alveolar cleft repair. Accurate estimation of graft volume in alveolar cleft patients can be performed using this new subtractive method. Compared with previous methods, this new subtractive method is time-saving and suitable for both unilateral and bilateral clefts. Surgeons can use this method to design a surgical plan for each patient before surgery within a short time, and with less cost.

Recording natural head position using an accelerometer and reconstruction from computed tomographic images.

ObjectivesThe concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position “when a man is standing and his visual axis is horizontal.” NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer.Materials and MethodsA total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements.ResultsThe average difference in the angles between the clinical photograph and the 3D model was 0.04° for roll and 0.29° for pitch. The paired ttests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05).ConclusionBy overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.

Cone-Beam Computed Tomography Analysis of Mucosal Thickening in Unilateral Cleft Lip and Palate Maxillary Sinuses.

To compare maxillary mucosal thickening and sinus volumes of unilateral cleft lip and palate subjects (UCLP) with noncleft (nonCLP) controls. Randomized, retrospective study of cone-beam computed tomographs (CBCT). University. Fifteen UCLP subjects and 15 sex- and age-matched non-CLP controls, aged 8 to 14 years. Following institutional review board approval and reliability tests, Dolphin three-dimensional imaging software was used to segment and slice maxillary sinuses on randomly selected CBCTs. The surface area (SA) of bony sinus and airspace on all sinus slices was determined using Dolphin and multiplied by slice thickness (0.4 mm) to calculate volume. Mucosal thickening was the difference between bony sinus and airspace volumes. The number of slices with bony sinus and airspace outlines was totaled. Right and left sinus values for each group were pooled (t tests, P > .05; n = 30 each group). All measures were compared (principal components analysis, multivariate analysis of variance, analysis of variance) by group and age (P ≤ .016 was considered significant). Principal components analysis axis 1 and 2 explained 89.6% of sample variance. Principal components analysis showed complete separation based on the sample on axis 1 only. Age groups showed some separation on axis 2. Unilateral cleft lip and palate subjects had significantly smaller bony sinus and airspace volumes, fewer bony and airspace slices, and greater mucosal thickening and percentage mucosal thickening when compared with controls. Older subjects had significantly greater bony sinus and airspace volumes than younger subjects. Children with UCLP have significantly more maxillary sinus mucosal thickening and smaller sinuses than controls.

Variations between Visually Estimated and Actual Convergence Angles of Tooth Preparations

Objectives: The purpose of this study was to compare the actual CA values of tooth preparations to those visually estimated by experienced prosthodontists, and to compare performance between prosthodontists. Materials and methods: Three prosthodontists visually estimated the mesiodistal and buccolingual convergence angles (MDCA and BLCA, respectively) of 65 randomly selected premolar preparations made by dental students on typodonts. Preparations were scanned in three dimensions and digitized. Actual MDCA and BLCA values were measured by three-dimensional imaging software. Data were analyzed by Friedman test (α=.05) and pairwise multiple comparisons with the Bonferroni adjustment (α=.0042). Results: The mean actual MDCA was 10.66 ± 3.96 degrees, compared to visual estimates of 13.86 ± 12.01, 21.94 ± 6.11, and 12.49 ± 8.38 degrees. The mean actual BLCA was 11.31 ± 4.80 degrees, compared to visual estimates of 13.32 ± 10.93, 23.52 ± 6.18, and 8.83 ± 5.75 degrees. The Friedman test resulted in χ2(3) = 68.54 (P<. 05) for MDCA and χ2(3) = 100.07 (P<.05) for BLCA. Multiple comparisons indicated that two prosthodontists provided CA estimates that were similar to each other (MDCA, P=1.0; BLCA, P=.042) and to the actual CA values (MDCA, P=.804 and P=.457; BLCA, P=1.0 and P=.006), whereas one prosthodontists provided higher CA estimates compared to the actual CA values and the other prosthodontists (P<.0042). Conclusions: One out of three of prosthodontists gave high CA estimates of tooth preparations compared to the actual CA and other prosthodontists’ estimates.

Three-Dimensional Ultrasound-Derived Physical Mitral Valve Modeling

Advances in mitral valve repair and adoption have been partly attributed to improvements in echocardiographic imaging technology. To educate and guide repair surgery further, we have developed a methodology for fast production of physical models of the valve using novel three-dimensional (3D) echocardiographic imaging software in combination with stereolithographic printing. Quantitative virtual mitral valve shape models were developed from 3D transesophageal echocardiographic images using software based on semiautomated image segmentation and continuous medial representation algorithms. These quantitative virtual shape models were then used as input to a commercially available stereolithographic printer to generate a physical model of the each valve at end systole and end diastole. Physical models of normal and diseased valves (ischemic mitral regurgitation and myxomatous degeneration) were constructed. There was good correspondence between the virtual shape models and physical models. It was feasible to create a physical model of mitral valve geometry under normal, ischemic, and myxomatous valve conditions using 3D printing of 3D echocardiographic data. Printed valves have the potential to guide surgical therapy for mitral valve disease.

Three-dimensional MDCT angiography of splanchnic arteries: pearls and pitfalls.

Fast scanning along with high resolution of multidetector computed tomography (MDCT) have expanded the role of non-invasive imaging of splanchnic arteries. Advancements in both MDCT scanner technology and three-dimensional (3D) imaging software provide a unique opportunity for non-invasive investigation of splanchnic arteries. Although standard axial computed tomography (CT) images allow identification of splanchnic arteries, visualization of small or distal branches is often limited. Similarly, a comprehensive assessment of the complex anatomy of splanchnic arteries is often beyond the reach of axial images. However, the submillimeter collimation that can be achieved with MDCT scanners now allows the acquisition of true isotropic data so that a high spatial resolution is now maintained in any imaging plane and in 3D mode. This ability to visualize the complex network of splanchnic arteries using 3D rendering and multiplanar reconstruction is of major importance for an optimal analysis in many situations. The purpose of this review is to discuss and illustrate the role of 3D MDCT angiography in the detection and assessment of abnormalities of splanchnic arteries as well as the limitations of the different reconstruction techniques.