In-vitro study on the accuracy of a simple-design CT-guided stent for dental implants
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An individual surgical stent fabricated from computed tomography (CT) data, called a CT-guided stent, would be useful for accurate installation of implants. The purpose of the present study was to introduce a newly developed CT-guided stent with a simple design and evaluate the accuracy of the stent placement.A resin template was fabricated from a hog mandible and a specially designed plastic plate, with 4 metal balls inserted in it for radiographic recognition, was attached to the occlusal surface of the template. With the surgical stent applied, CT images were taken, and virtual implants were placed using software. The spatial positions of the virtually positioned implants were acquired and implant guiding holes were drilled into the surgical stent using a specially designed 5-axis drilling machine. The surgical stent was placed on the mandible and CT images were taken again. The discrepancy between the central axis of the drilled holes on the second CT images and the virtually installed implants on the first CT images was evaluated.The deviation of the entry point and angulation of the central axis in the reference plane were 0.47±0.27 mm, 0.57±0.23 mm, and 0.64±0.16°, 0.57±0.15°, respectively. However, for the two different angulations in each group, the 20° angulation showed a greater error in the deviation of the entry point than did the 10° angulation.The CT-guided template proposed in this study was highly accurate. It could replace existing implant guide systems to reduce costs and effort.Abstract Background Although the relatively high incidence of coronal fractures in the supracondylar–intercondylar fractures is well established, little is currently known about the morphology of those fractures. Herein, we characterized the coronal fractures in AO/OTA type 33-C3 and assessed their differences with Busch–Hoffa fractures (33-B3). Methods We retrospectively collected 61 cases of AO/OTA type 33-B or C fractures with coronal plane fragments and generated three-dimensional fracture maps of those with coronal fractures based on CT imaging and measured angle α (the angle between the coronal fracture and the posterior condyle axis in the axis plane) and angle β (the angle between the coronal fracture and the posterior femoral cortex in the sagittal plane). Results Thirty-three cases (32%) of AO/OTA type 33-C fractures contained coronal fragments. Most of them were type 33-C3 fractures. Angles α and β for type 33-C3 were significantly smaller than for type B3 at the lateral condyle, while the angles at the medial condyle were not significantly different. The fracture maps showed that the coronal fractures and the articular comminution area were more anterior in type 33-C3. Conclusions The incidence of coronal fractures was 32% and 67% in AO/OTA types 33-C and 33-C3, respectively. Our findings suggest that coronal fractures differed between both types, emphasizing the potential need for different treatment approaches.
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This study aimed to compare measurement of the lateral cerebral ventricular diameter using either the traditional axial view or the coronal plane.We performed a prospective study on 144 fetuses, 77 evaluated as part of a routine fetal scan and 67 referred for a neurosonogram. Distal lateral ventricles were measured both in axial and coronal plane.Good visualization of the ventricles was achieved in 91% of the cases using the coronal plane (both ventricles) and in 95% of the cases using the axial plane (only the distal ventricle) (p > 0.001). The mean width of the distal lateral ventricle in the axial plane was 7.9 ± 1.9 mm versus 8.2 ± 1.9 mm on the coronal plane (p < 0.001). This larger diameter by 0.3 mm was not dependent on the indication for the scan or the gestational age. Slight asymmetry was present on coronal images in the routine group (0.2 mm), and that was even larger in the referral group (1.6 mm) (p < 0.001).Coronal measurement of both ventricles is feasible and has the advantage over measurement in the axial view in which only the distal ventricle is clearly visible and measurable.
Lateral ventricles
Cerebral ventricle
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Morphology
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In order to determine the value of coronal magnetic resonance (MR) in diagnosing thoracic abnormalities, the multisection coronal spin echo MR images were reviewed of 10 normal subjects and 20 patients with thoracic abnormalities. In the abnormal patients, coronal images were compared with transaxial MR images obtained with TR values of 0.5 and 2.0 sec. In general, coronal imaging was of value in several situations. It allowed structures oriented in the coronal plane to be imaged along their longitudinal axes, provided an additional perspective and increased the confidence of diagnosis, and helped clarify anatomic relationships difficult or impossible to resolve on transaxial images because of volume averaging. Specifically, coronal images were sometimes superior to transaxial images in evaluating the aorticopulmonary window and masses at the lung apex or base. Transaxial images were often superior in evaluating the pretracheal space, subcarinal space, and hili. Within the pulmonary hili, lateral hilar masses were better defined on coronal images than were anterior or posterior hilar masses. Coronal images obtained with a TR of 1.0 sec (10 sections) allow evaluation of most node-bearing mediastinal compartments and provide adequate mass/fat contrast.
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Objective:The effects on treatment of coronal fractures with hydrocylapatite have been evaluated.Methods:Flling with hydrocylapatite cataplasm and coronal coverage were performed after disinfections in 68 cases coronal fractures.Results:in 68 cases after treatment of coronal fractures,52 cases succeed,9 cases normal,7 cases failed.Conclusion:it is a ideal method to treat coronal fractures with filling hydroxylapatie.
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Objective To assess the value of coronal MPR of 64-slice spiral CT in investigation of the cause of bowel obstruction.Methods Thirty-eight patients with different kinds of bowel obstruction underwent 64-slice spiral CT examination,and the data of axial and coronal image were reconstructed.Then the images were analyzed respectively by 4 readers in group A and B.Doctors in one group viewed the axial images first,then the coronal images,while in the other group viewed the coronal images first and then the axial images.The CT findings were compared with the surgical and pathologic results.Results The accuracy of coronal MPR of 64-slice spiral CT for investigating the cause of bowel obstruction was similar to that of axial MPR(86.84% vs 89.47%),and both had high accuracy.Diagnostic accuracy and confidence of doctors were improved obviously with the combination of axial images and coronal images(both 94.73%).Conclusion Coronal MPR of 64-slice spiral CT has very high clinical application value for diagnosing bowel obstruction.Diagnostic accuracy and doctors' confidence are improved with the help of axial images.
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To evaluate the use of coronal magnetic resonance (MR) imaging in assessment of disk position in the temporomandibular joint (TMJ), sagittal and coronal 1.5-T MR images were obtained of 158 TMJs in 79 patients. From the sagittal images, medial or lateral displacement was suspected in 24 joints. Displacement could be confirmed from coronal images in 21 joints but could not be confirmed in three. In 18 other joints, the coronal images revealed a lateral or medial displacement that was not evident on sagittal images. In seven of these 18, displacement was purely lateral or purely medial, whereas the other 11 had a combination of anterior and lateral or medial displacement. On the basis of only sagittal images, the seven with pure displacement would have been diagnosed as normal. Use of the coronal plane added diagnostic information to that obtained with sagittal imaging and may increase diagnostic accuracy. Coronal images are therefore recommended as a supplement to sagittal images in MR imaging evaluation of the TMJ.
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Objective To study the imaging features of the normal vestibular aqueduct (VA) on coronal CT scans, to provide further evidence for the diagnosis of sensorineural hearing loss of unknown reason.Materials and Methods Both axial and coronal CT scanning were performed in 52 cases (104 normal ears). The width and length of VA, as well as the angle between the long axis of VA and horizontal level were measured. The data thus obtained were statistically analyzed. Results On coronal plane, both the displaying rate and measurable rate of VA isthmus were 100%. On axial plane, the displaying rate of VA isthmus was 100%, while its measurable rate was only 88.3%. Both the displaying rate and measurable rate of the posterior part of VA were 61.5%. On coronal plane, the width and length of VA isthmus were (0.87±0.57) mm and (3.07±1.34) mm, while the width and length of the posterior part of VA were 1.23±0.51mm and (4.89±1.61) mm, respectively. The normal upper limit of VA isthmus was 4.4mm by 1.5mm (length by width).Conclusion On coronal plane, the VA course can be well demonstrated and the VA isthmus can be easily measured. The normal values of VA isthmus on coronal plane are proposed. Combination of coronal with axial images will improve the diagnostic accuracy of VA dilatation and, thus, help find out the etiology of sensorineural hearing loss.
Vestibular aqueduct
Horizontal plane
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The results of a study undertaken prospectively in 1983 and 1984 to assess the value of computed tomography (CT) and conventional tomography in the planning of radiotherapy for laryngeal cancer are presented. Of 32 cases treated in 1983, 23 had both CT scans and coronal plane tomography prior to radiotherapy. At the end of 1983 these radiographs were reviewed and an assessment made of their value in treatment planning. As a result of this review it was decided that cancers of the larynx confined to the vocal cords should routinely have conventional coronal plane tomograms rather than CT scans. All other cases were to have CT scans and not tomograms. The results of following this policy in 1984 confirm that it is effective. There was no detriment to patients with early vocal cord cancers in performing coronal plane tomograms rather than CT scans. The survival at 24 months of both cohorts was 93%. In the more invasive cancers of the larynx, greater information about the extent of the disease was obtained using CT scans, and improved treatment plans resulted. When compared with a historical group, there appears to be an advantage for local control, 27.3% of the study group suffering local recurrence as opposed to 53.6% of the historical group.
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