508 コーンビーム型 3 次元 CT 画像より構築したヒト大腿骨近位部の有限要素モデル

Objective To establish a way to measure the injury severity of articular surface due to posterior malleolus fracture and investigate its clinical significance based on three-dimensional reconstruction technique. Methods Between May 2009 and March 2014, 138 cases of peri-ankle injury combined with posterior malleolus fracture were treated. Lateral radiographs were reviewed to measure the ratio of posterior fragment area to distal tibial plafond area using the common method. Three-dimensional CT images were examined to measure ratio of the area of injury using the three-dimensional measuring method. Statistical comparison was made using the t-test and intraclass correlation coefficient (ICC). Results Measurement failed on 33 lateral radiographs and 13 three-dimensional CT images. Six cases cannot be measured by both imaging technology, so results of 98 cases were compared. Ratio of posterior fragment area to tibial plafond area was (16.2±7.2)% measured by radiographs and was (29.6±10.1)% by three-dimensional CT scans (P<0.05). Three-dimensional CT measurements showed higher intra and inter-observer agreement (ICC of 0.973 to 0.942) than that in radiographic measurements (ICC of 0.875 to 0.860). Conclusion Three-dimension CT assessment of the extent of injury to articular surface because of posterior malleolus fracture is reliable and reproducible, but radiographic assessment may underestimate the injury and influence the choice of surgical indications. Key words: Ankle injuries; Imaging, three-dimensional; Tomography, X-ray computed

Technological advances in computer image analysis have made possible three-dimensional (3D) surface reformations of anatomic structures from contiguous axial CT slices. We have recently utilized this new imaging technique in six patients with primary, isolated craniosynostosis. In each case 3D CT demonstrated the exact extent of synostosis, and in five cases 3D CT images facilitated surgical planning by precisely localizing the proper site for craniectomy. Three-dimensional CT may be a useful adjunct to imaging and surgical planning in this condition.

Objective To investigate the influence of bony lacrimal passage anatomy in the management of nasolacrimal duct obstruction treated by retrograde intubation procedure.Methods 75 eyes of 71 cases of primary nasolacrimal duct obstruction in adults were studied.The patients underwent three-dimensional CT imaging before surgery to detect the length and minimum diameter of bony lacrimal passage.The Y shape silicone tubes were intubated in lacrimal passages retrogradely.The tubes were removed at 3 months after surgery.The patients were followed up for over 1 year.Results The tubes were intubated successfully by one surgery in all cases.When the tubes were removed,saline irrigation revealed complete free passages in 67 eyes (89.33％) and some blockage in 8 eyes (10.67％).At 1-3 months after removal of the tubes,canalicular obstructions were found in 14 eyes.These 14 cases were regarded as the uncured group and other 61 eyes were regarded as the cured group.The average lengths of bony lacrimal passage were (13.40 ± 0.51) mm in the cured group and (13.71 ± 0.41) mm in the uncured group.The minimum diameters of bony lacrimal passage were (3.47 ±0.34) mm in the cured group and (3.23 ±0.28) mm in the uncured group.The differences of average lengths and minimal diameters of bony lacrimal passage in two groups were statistically significant (t =4.81,P ＜ 0.01 ; t =5.64,P ＜ 0.01).Conclusion Retrogarde intubation procedure has good clinical efficacy in the treatment of nasolacrimal duct obstruction.The individual operation should be designed based on the three-dimensional CT imaging of bony lacrimal passage to increase the success rate of surgery. Key words: Obstruction, nasolacrimal duct; Intubation, retrograde; Study, clinical

6538 POSTER Comparison of the Different Planning Targets Defined Basing on Three-dimensional CT and Four-dimensional CT Images for Liver Cancer

In anterior cruciate ligament (ACL) reconstruction, sharp angulation of the graft at tunnel aperture increases local strain to the graft. The purpose of this study is to investigate the relationship between femoral tunnel location and femoral graft bending angle after ACL double bundle reconstruction (ACL-DBR) with two different drilling techniques. In ACL-DBR, femoral tunnel was created by two techniques; outside-in technique (26 patients, group A) and transportal technique (25 patients, group B). CT scan was taken at 1week postoperatively. The position of femoral tunnel exit on the lateral femoral cortex, and intra-articular femoral and tibial tunnel aperture of the anteromedial bundle (AMB) and postero-lateral bundle (PLB) was measured using a rectangular frame on three-dimensional CT images. Femoral graft bending angle was measured using two-dimensional CT images. Femoral tunnel exits of AMB and PLB in group A were significantly anterior and proximal than those in group B (p<0.05), while there was no significant difference in intra-articular femoral and tibial tunnel apertures between group A and B. A mean femoral graft bending angle of AMB was 80.3° in group A and 69.2 degrees in group B, respectively (p<0.05). A mean femoral graft bending angle of PLB was 66.3° in group A and 64.6° in group B, respectively. In both groups, a significant (p<0.05) correlation (r<-0.4) was observed between the position of the femoral tunnel exit (anterior-posterior ratio from femoral anterior border line) and the femoral graft bending angle in AMB. Since the femoral tunnel exit in outside-in technique was located more anterior and proximal, femoral graft bending angle of AMB in outside-in technique was greater than that in transportal technique. Anterior position of the femoral tunnel exit in AMB increased femoral graft bending angle in outside-in and transportal techniques.

The purpose of this study was to investigate enophthalmos by measuring the volume of various orbital structures using off-line computer techniques on images generated by a CT scanner. Eleven patients with enophthalmos had CT scans of the orbits consisting of 30 to 40 adjacent 1.5-mm slices. The data from the scans were analyzed on a Nova 830 stand-alone computer system using software programs that allowed measurement of total bony orbital volume, total soft-tissue volume, globe volume, orbital fat volume, neuromuscular tissue volume, and apex-to-globe distance in the horizontal plane. These data were analyzed comparing the volumes in the normal eye with the volumes in the enophthalmic eye in each patient. The analysis demonstrated a statistically significant increase in bony orbital volume in the enophthalmic eye, but the total soft-tissue volume, fat volume, neuromuscular tissue volume, and globe volume were the same as in the normal eye. The apex-to-globe distance, a measure of the degree of enophthalmos, was less in the enophthalmic eye than in the normal eye. These results suggest that in the majority of patients, the cause of posttraumatic enophthalmos is increased bony orbital volume rather than by soft-tissue loss or fat necrosis. (Several patients showed no volume discrepancies, and it is likely that cicatricial contracture is responsible for the enophthalmos in these cases.) This study suggests that the objective of surgery for correction of enophthalmos in patients with a volume discrepancy should be to decrease the volume of the bony orbit and to increase the anterior projection of the globe.

Clinical application of a solid three-dimensional model for orbital wall fractures

This study was conducted to evaluate the biomechanics of facial fractures caused by steering wheel loading. Twelve intact fresh human cadaver heads were impacted onto standard or energy-absorbing steering wheels with a custom-designed and validated vertical-drop apparatus. Either zygoma was impacted once at a velocity of 2.0-6.9 m/s. The specimens were oriented to permit a direct comparison between pretest and posttest radiography, and two-dimensional and three-dimensional CT images. Bone mineral content was determined, and biomechanical forces, accelerations, and deformations were recorded. More severe fractures were associated with higher forces on the zygoma. With increasing velocities, fractures initiated at the zygomatic region propagated to other unilateral regions such as the mandible and orbit or to the contralateral side. Less facial trauma was observed with energy-absorbing steering wheels compared with standard wheels at similar impact velocities. Bone mineral content did not correlate well with specimen age or with fracture severity. Clinically significant fractures were identifiable on 3-D CT images. The flexibility of 3-D CT in evaluating the spatial extent of facial abnormalities in different orientations may have significant impact in planning surgical procedures.

The purpose of this study was to obtain quantitative information of the relative displacements and rotations of the carpal bones during movement of the wrist. Axial helical CT scans were made of the wrists of 11 volunteers. The wrists were imaged in the neutral position with a conventional CT technique, and in 15-20 other postures (flexion-extension, radial-ulnar deviation) with a low-dose technique. A segmentation of the carpal bones was obtained by applying a deformable surface model to the regular-dose scan. Next, each carpal bone, the radius, and ulna in this scan was registered with the corresponding bone in each low-dose scan using a three-dimensional matching technique. A detailed definition of the surfaces of the carpal bones was obtained from the regular-dose scans. The low-dose scans provided sufficient information to obtain an accurate match of each carpal bone with its counterpart in the regular-dose scan. Accurate estimates of the relative positions and orientations of the carpal bones during flexion and deviation were obtained. This quantification will be especially useful when monitoring changes in kinematics before and after operative interventions, like mini-arthrodeses. This technique can also be applied in the quantification of the movement of other bones in the body (e.g., ankle and cortical spine).

Preoperative Planning of Pelvic Osteotomy Using Three-dimensional CT Imaging and Stereolithograph

ObjectiveTo compare a new classification with the Garden classification by exploring their relationships with vascular injury.MethodsThis retrospective study enrolled 73 patients with subcapital femoral neck fracture from July 2015 to November 2018, including 32 males and 41 females with an average age of 47.2 years. All patients were classified by the Garden classification using anteroposterior X‐ray imaging and by a new classification system based on three‐dimensional CT imaging. The blood supply of the affected femoral head in these patients was evaluated based on DSA images. Correlations between the two classifications and the degree of vascular injury were assessed.ResultsThe results of the DSA examination indicated that eight patients had no retinacular vessel injury, 20 patients had one retinacular vessel injury, 35 patients had two retinacular vessel injuries, and 10 patients had three retinacular vessel injuries. The degree of vascular injury was used to match the two fracture classifications. Forty‐nine Garden classifications (Type I‐IV: 8, 12, 23, 6, respectively, 67.12%) and 66 new classifications (Type I‐IV: 8, 20, 32, 6, respectively, 90.41%) corresponded to the degree of vascular injury (p < 0.05). The Garden classification showed moderate reliability, and the new classification showed near perfect agreement (Interobserver agreement of k = 0.564 [0.01] in Garden classification vs. Garden classification k = 0.902 [0.01] for the five observers).ConclusionsThe new classification system can accurately describe the degree of fracture displacement and judge the extent of vascular injury.

Orbital Volume Measurements in Enophthalmos Using Three-Dimensional CT Imaging

Three-dimensional computed tomographic scanning is a valuable adjunct in the diagnosis and treatment of disease processes involving the spine. We present our experience with this noninvasive radiological diagnostic technique in 32 patients with vertebral column abnormalities ranging from craniovertebral junction disorders to fractures of lumbar vertebrae. The three-dimensional CT images often demonstrate pathological conditions and occult lesions that are not adequately defined by conventional radiographic means.

Surgical treatment of internal carotid artery aneurysms around the carotid siphon is discussed. The surgical approach to the aneurysms in this region, is as follows: 1. A fronto-temporal approach with the patient in a 45 degrees semi-sitting position to decrease venous pressure. 2. A Dolenc approach cutting a part of the dura mater of the superior orbital fissure to facilitate removal of the anterior clinoid process and unroofing of the optic canal. 3. Opening the medial triangle followed by transection of the optic canal dural sheath. Carotid siphon aneurysms can be divided into three groups anatomically; aneurysms of the ophthalmic segment (C2), those of the clinoid segment (C3), and those of the horizontal segment (C4). We present 29 cases of aneurysms arising from the C2 or C2/3 segment, 14 cases arising from the C3 or C3/4 segment, and 11 cases arising from the C4 segment. Anatomic localization of the aneurysms was established preoperatively by angiography and three-dimensional CT imaging. Small aneurysms of the ophthalmic segment projecting infero-medially can be clipped using a contralateral approach via the prechiasmatic root. Aneurysms of the ophthalmic segment projecting superiorly can be clipped following resection of the anterior clinoid process. The clinoid process should be resected intradurally with direct visualization of the aneurysms. Straight side-angled clips are suitable for these aneurysms. Carotid cave aneurysms, which include aneurysms of the ophthalmic segment oriented infero-medially and of the clinoid segment projecting postero-medially, can be clipped using curved fenestrated clips via Dolenc's extradural approach. For accurate clipping, opening of the medial triangle and full mobilization of the IC at the clinoid segment and optic nerve by unroofing the optic canal are required. Aneurysms of the horizontal portion are clipped after full exposure of the artery in the cavernous sinus only when the aneurysms are large and symptomatic. We used the fronto-temporal and Dolenc approaches and applied fenestrated clips to aneurysms oriented or postero-medially and straight or oblique clips to aneurysms projecting antero-laterally. Out of 40 aneurysms which underwent surgical clipping, 37 resulted in good post-operative recovery. There were three deaths secondary to complications of vasospasm and three cases with post-operative visual loss. The classification of these aneurysms and the surgical techniques we employed are discussed in detail.

Hemoptysis is a common clinical emergency, bronchial arterial embolization is considered to be an effective treatment. The presence of coronary artery-bronchial artery fistula (CBF) may lead to recurrence of hemoptysis after treatment. It is necessary to investigate the imaging characteristics of a CBF and its correlation with the severity of pulmonary disease. With the development of multi-detector computed tomography, our study used the 320-slice CT bronchial artery angiography technology to observe and visualize blood vessels. The image and clinical data of 2015 hemoptysis patients with 320-slice CT bronchial artery angiography were retrospectively reviewed from January 2015 to December 2019. The axial and three-dimensional CT images were analyzed. The incidence, anatomical characteristics of CBF and pulmonary disease severity score were evaluated. A total of 12 CBF vessels were detected in 11 patients. We found that the incidence of CBF in this group was 0.55% (11/2015). Mean CBF diameter was 1.9 mm (1.2-2.5mm). The course of CBF usually was relatively fixed. The proportions of CBF originated from the left circumflex artery, right coronary artery, and left anterior descending artery were 75%, 16.7% and 8.3%, respectively. Preliminarily analysis of the correlation between the trend of CBF and the pulmonary diseases severity score showed that CBF was more likely to communicate with a bronchial artery on the side with a higher severity score. CBF may occur in patients with chronic pulmonary disease and hemoptysis, and its origin, course and trend are characteristic. Detailed and comprehensive computed tomography angiography image analysis is helpful to improve the clinical treatment of hemoptysis with CBF.