应用锥形束CT评价前牙唇舌侧牙槽骨高度及厚度的研究

目的评价锥形束CT(CBCT)在体内外定量测量前牙唇舌侧牙槽骨高度及厚度的准确性。方法体外实验利用CBCT测量10个干下颌骨下前牙牙槽窝的高度和厚度,并与直接测量结果进行比较;体内实验选取待拔除的22颗前牙,拔除前使用CBCT测量牙槽骨的高度和厚度,并与拔除后即刻直接测量的结果进行比较。结果体外实验CBCT与直接测量结果之间的差异无统计学意义(P>0.05);体内实验CBCT对唇侧牙槽骨厚度测量结果大于CBCT测量结果(P<0.05),而其他3个参数二者之间的差异无统计学意义,造成差异的原因可能与拔牙的损伤和CBCT拍摄过程中患者的移动有关。结论 CBCT可以较好地反映前牙唇舌侧牙槽骨高度和厚度的实际情况。     

Prevalence of and risk factors for postoperative complications after lower third molar extraction: A multicenter prospective observational study in Japan

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient’s background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040–1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333–3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050–2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079–6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574–4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction.     

A Pilot Retrospective Study on the Effect of Bone Grafting after Wisdom Teeth Extraction

This study aimed to retrospectively investigate the effect of bone graft after extraction of wisdom teeth impacting with the distal aspect of the second molar, on soft tissue wound healing, bone loss, and periodontal parameters. Sixteen patients treated an for impacted mandibular wisdom tooth at least one year ago were re-called (18 teeth). Dental panoramic tomography and periodontal parameters were assessed. A graft material was used to fill the post-extractive sockets in the test group (GUIDOR easy-graft CRYSTAL), whereas in the control group, the socket was filled using a collagen sponge and blood clot (Hemocollagene, Septodont, Matarò, Spain). The radiographic bone loss was measured at the distal aspect of the second molar. The Wilcoxon singed-rank test for paired data was performed to evaluate statistical differences. In the test group, only two cases out of nine showed bone loss, with an average of 0.55 ± 1.30 mm. Conversely, in the control group, five teeth out of nine showed bone resorption with an average of 1.22 ± 1.30 mm. However, the differences were not statistically significant. Periodontal parameters at the second molar demonstrated similar behavior between the test and control groups. Soft tissue healing complications were lower in the grafted compared to the comparator sites without reaching statistical significance. Within the limitations of the present study, no difference was found between the two groups.     

The analysis of root canal curvature and direction of maxillary lateral incisors by using cone-beam computed tomography: A retrospective study

The aim of this study was to investigate root canal curvature and direction of maxillary lateral incisors in Shandong, China.Cone beam computed tomography (CBCT) images of 176 maxillary lateral incisors of 88 patients were collected in Shandong Province, China. Software included with CBCT was used to measure the angle of root canal curvature of maxillary lateral incisors on the maximum bending plane. In addition, the direction of each root canal was recorded. The data were statistically analyzed by SPSS 17.0 software package.The results showed that all the samples had a single canal (Vertucci''s type I). The incidence of straight root canals, curved root canals, and S-type root canals was 39.2%, 58%, and 2.8%, respectively. The difference in the mean angle of root canal curvature failed to identify any differences between the left and right side (P > .05). The most curved root canal of maxillary lateral incisors oriented in the palato-distal direction.The maxillary lateral incisors were mainly curved root canals of which the proportion of moderate curvature was the largest. Software included with CBCT would provide some valuable information for root canal instrumentation of maxillary lateral incisors.     

Association between the eruption of the third molar and caries and periodontitis distal to the second molars in elderly patients

The objective of this study was to verify whether caries and periodontal diseases, when present on the distal surface of the second molars (M2s), are associated with the eruption of the third molars (M3s). In this split-mouth study, we evaluated 70 elderly patients with unilateral maxillary or mandibular M3s who presented to the outpatient clinics of two hospitals. Patients underwent comprehensive oral examinations and radiographical measurements, and we assessed the outcomes of periodontal disease and caries. Periodontal measurements included plaque index, bleeding on probing, and periodontal probing pocket depth (PD). Moreover, caries were assessed through visual–tactile examination and radiography. We performed the χ² test to determine factors associated with M3 and non-M3 outcomes. Eighty-one unilateral erupted M3s were observed in the study patients. Both the distobuccal region (p < 0.0001) and the distolingual region (p = 0.006) had a higher PD on the nonextraction side than the extraction side, and the caries rate was significantly higher on the nonextraction side than on the extraction side (p <0.0001 on M2 with caries and p = 0.003 on M2 with distal caries). M3 eruption, at the same or different occlusal plane levels of M2, is a risk factor for periodontal diseases and caries in M2s in elderly patients. M3s may continue to negatively impact dental health well into later life.     

Assessment of Differences in the Dimensions of Mandible Condyle Models in Fan- versus Cone-Beam Computer Tomography Acquisition

Modern treatment in the field of head and neck surgery aims for the least invasive therapy and places great emphasis on restorative treatment, especially in the case of injury and deformation corrective surgery. More and more often, surgeons use CAD/CAM (Computer-Aided Design and Computer-Aided Manufacturing) tools in their daily practice in the form of models, templates, and computer simulations of planning. These tools are based on DICOM (Digital Imaging and Communications in Medicine) files derived from computed tomography. They can be obtained from both fan-beam (FBCT) and cone-beam tomography (CBCT) acquisitions, which are subsequently segmented in order to transform them into a 1-bit 3D model, which is the basis for further CAD processes. Aim: Evaluation of differences in the dimensions of mandible condyle models in fan- versus cone-beam computer tomography for surgical treatment purposes. Methods: 499 healthy condyles were examined in CT-based 3D models of Caucasians aged 8–88 years old. Datasets were obtained from 66 CBCT and 184 FBCT axial image series (in each case, imaging both mandible condyles resulted in the acquisition of 132 condyles from CBCT and 368 condyles from FBCT) and were transformed into three-dimensional models by digital segmentation. Eleven different measurements were performed to obtain information whether there were any differences between FBCT and CBCT models of the same anatomical region. Results: 7 of 11 dimensions were significantly higher in FBCT versus lower in CBCT (p < 0.05).     

下颌第三磨牙阻生牙颊侧切口拔除的临床效果观察

目的观察下颌第三磨牙近中水平阻生颊侧切口拔除的临床效果。方法对60例拔除下颌第三磨牙近中水平阻生牙的患者,在进行切口选择时,采用颊侧垂直切口进行拔除,观察患者术后出血、疼痛、软组织水肿反应以及创口黏膜的愈合情况。结果 (1)60例拔除下颌第三磨牙近中水平阻生牙的患者中,30颗下颌第三磨牙近中水平阻生牙都能完整拔除;(2)采用颊侧垂直切口进行拔除时,手术区域牙体充分暴露,视野清晰,去除相关阻力时有足够的空间进行相关操作;(3)患者手术后局部炎症水肿症状少。结论采用颊侧垂直切口,适合应用于下颌第三磨牙水平阻生、近中阻生以及垂直阻生。     

Radiographic assessment of root canal morphology of mandibular central incisors using new classification system: A cross-sectional study

Lack of basic knowledge about the external and internal anatomies of the root canal system and common variations in teeth may lead to various procedural errors or treatment failure. In this study, the root canal configurations of mandibular incisors and the symmetry of the contralateral incisors of Saudi Arabian subpopulations were analyzed and determined using cone beam computed tomography (CBCT). A retrospective evaluation of 700 patients was conducted, and 1260 fully developed permanent mandibular central incisors were assessed. The number of root canals was determined, and the internal root canal anatomies were categorized based on Ahmed et al.’s criteria. The CBCT images were independently evaluated by 2 trained dentists and an endodontist. The data were assessed using the chi-square and one-way analysis of variance tests. All the mandibular central incisors included in the study were single-rooted. According to Ahmed et al’s classification system, the most common classification (82.6%) was ¹ManA¹ (Vertucci type I), followed by ¹ManA^1-2-1 (Vertucci type III; 13%). Second canals were more frequently recorded in the male participants than in the female participants. The root canal configuration between contralateral incisors was largely symmetrical. Most of the mandibular incisors in the examined Saudi Arabian population had a single canal. Nevertheless, a substantial number of patients had a complex root morphology. Hence, CBCT can be utilized as a potential supplementary tool during root canal treatment.     

Use of Noncontrast Computed Tomography of the Inferior Vena Cava for Real-Time Imaging Guidance for the Placement of Inferior Vena Cava Filters

Appropriate placement of an inferior vena cava (IVC) filter necessitates imaging of the renal veins because when an IVC filter is deployed its tip should be at or below the inferior aspect of the inferiormost renal vein. Traditionally, imaging during placement of IVC filters has been with conventional cavography and fluoroscopy. Recently, intravascular ultrasound has been used for the same purpose but with additional expense. Morbidly obese patients often exceed the weight limit of fluoroscopy tables. In addition, short obese patients are at risk of falling from narrow fluoroscopy tables. For such patients, computed tomography (CT) guidance is a viable alternative to conventional fluoroscopic guidance.IVC placement was performed in the CT suite for two obese patients who exceeded the weight limits of the available fluoroscopy tables. In one case, a Vena-Tech filter (Braun Medical, Melsungen, Germany) was placed using CT fluoroscopy. In the second case, a Recovery (Bard, Murray Hill, NJ) filter was placed using intermittent limited z-axis scanning.In the first case, the filter was placed below the level of the renal veins and above the confluence of the iliac veins, which is acceptable placement. In the second case, with refinement of technique, the filter tip was placed less than 1 cm below the inferiormost renal vein, which is considered optimal placement.CT of the IVC precisely images the renal veins and can characterize their number and their confluence with the IVC. CT guidance is a viable alternative to fluoroscopic guidance for the placement of IVC filters in morbidly obese patients.     

Mobile computed tomography for the efficient allocation of medical resources in patients with COVID-19 pneumonia: A case report

Rationale:The highly contagious Coronavirus 2019 (COVID-19) infection raise social and economic burden. Medical staff and resources are being diverted for the care of patients with COVID-19. There are problems for healthcare systems, including burnout syndrome for the medical staff and exhaustion of medical resources.Patient concerns:The patient was a 65-year-old woman presenting with fever, cough, and dyspnea due to COVID-19 pneumonia. She received antiviral agents, broad-spectrum antibiotics, and conservative treatment. Although her clinical condition improved, there was no significant improvement in portable chest X-ray results.Diagnoses:Due to concerns over the propagation of infection when transferring to patients for scanning and the need for excessive medical personnel to move patients, we moved a mobile chest computed tomography (CT) machine to an isolation ward for CT scanning.Interventions:We report our experience using mobile chest CT to effectively allocate medical resources and assess treatment response in patient with COVID-19 pneumonia.Outcomes:Follow-up mobile CT scans disclosed progressive resolution of the multifocal ground-glass opacities and mixed consolidations distributed peripheral to subpleural spaces. During the mobile chest CT scan, there were no adverse or unforeseen events. Three medical personnel were required to performed mobile chest CT, including a clinician, a nurse, and a radiologist.Lessons:As a result of using mobile chest CT on COVID-19 patients, the number of medical personnel required for CT scanning decreased by about 83%, rapid, and safe compared with a patient who performed conventional CT.     

Radiological findings of alveolar hydatid disease of the lung caused by Echinococcus multilocularis

Alveolar hydatid disease is a highly malignant form of echinococcosis caused by the larvae of the cestode Echinococcus multilocularis. Alveolar hydatid disease always affects the liver and can metastasise to the lungs and brain. The case reports describe the radiological features of alveolar hydatid disease of the lung caused by E. multilocularis. Multiple nodules which varied in size and shape were seen on CXR, CT showed most nodules to be lobulated, well circumscribed and of varying shape. Multiple lobulated lesions located between two segments of the lung and of varying shape appear to be characteristic of pulmonary alveolar hydatid disease caused by E. multilocularis.     

Hepatic veno-occlusive disease after taking Gynura Rhizome: The value of multidetector computed tomography in diagnosing the disease and evaluating the clinical therapeutic effect

Aim: We conducted this study to evaluate the role of multidetector computed tomography (MDCT) in diagnosing and differential diagnosis hepatic veno‐occlusive disease (HVOD), and as well as assessing the clinical therapeutic effects. Methods: From 2007 to 2010, 10 inpatients with weight increasing, liver pains, ascites, jaundice and history of taking gynura rhizome before hospitalization were scanned with a 64‐MDCT. The data were reconstructed every 0.625 mm and reviewed using multiplanar reconstruction (MPR) and liver CT angiography (CTA) on a GE AW4.2 workstation. Patients were re‐scanned with MDCT after medication so that the clinical therapeutic effect could be evaluated before the patients discharging from hospital. Results: In 10 HVOD patients, the diagnoses of MDCT were coincident with clinical results. All patients had ascites and pleural fluid, hepatomegaly except the caudate lobe in MDCT. Failure to view hepatic veins in hepatic 3 phase scans, but portal veins and inferior vena cava were unobstructed. In portal‐phase, hepatic enhancements were non‐uniform. Three patients were incorrectly diagnosed before hospital admission. All patients improved significantly after hepato‐protection and supporting therapy. No ascites, hydrothorax, hepatomegaly and obstruction of hepatic veins were observed by MDCT before patients were discharged from hospital. Conclusion: Multidetector computed tomography combined with MPR and liver CTA images are helpful in the diagnosis and differential diagnosis of HVOD and in the evaluation of clinical therapeutic effects.     

Factors affecting survival after excision of the rectum for cancer

PURPOSE: The aim of this study was to identify and categorize the independent prognostic effects of patient, clinical, operative, and pathology variables on long-term survival after anterior resection or abdominoperineal excision of the rectum for cancer. METHODS: Proportional hazards regression analysis was used to analyze prospective data from 709 patients who underwent surgery at Concord Hospital during a 23-year period. No patient received adjuvant therapy. RESULTS AND CONCLUSIONS: After adjusting for age and clinicopathologic stage, significantly poorer survival was experienced by males, patients with extensive tumor adherent to other organ(s), those with a high-grade tumor or a tumor showing venous invasion, those who had a postoperative cardiovascular or respiratory complication, and those who did not undergo surgery by a colorectal surgeon specialist. The nature of the operation performed had no independent effect on survival.Read at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996, and at the Tripartite Meeting, London, United Kingdom, July 8 to 10,1996.     

18F-FDG PET/CT imaging for aggressive melanotic schwannoma of the L3 spinal root: A case report

Rationale:Melanotic schwannoma (MS) is an unusual variant of a nerve sheath neoplasm that accounts for less than 1% of all primary peripheral nerve sheath tumors. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) has unique value in detecting malignant MS lesions. To date, only 4 cases of MS with hepatic metastasis have been reported. Herein, we report the fifth case, which is the first reported patient with MS of Asian ethnicity with hepatic metastasis.Patient concerns:A 29-year-old woman with a 1-day history of backache was admitted to our hospital. PET/CT showed a paravertebral heterogeneous soft tissue mass along the spinal nerve at the L2-L3 level with strong FDG uptake, and a nodule with increased FDG uptake in the lateral lobe of the left liver.Diagnosis:A puncture biopsy of the L3 bony destruction and surrounding soft tissue mass was performed. The final diagnosis was spinal MS with hepatic metastasis.Interventions:The patient underwent 6 courses of systemic chemotherapy.Outcomes:The patient did not receive further treatment for half a year after the end of chemotherapy and recovered well.Lessons:Unlike conventional schwannomas, which are completely benign, MS has an unpredictable prognosis. It is thought to have low malignant potential, and the malignant type tends to metastasize. FDG PET/CT has a unique and important value in the differential diagnosis of benign and malignant lesions, in detecting occult metastases, monitoring the treatment response, and assessing the prognosis of MS.     

Mycotic aneurysm of the root of left subclavian artery associated with aortic coarctation discovered by echocardiography

A 16‐year‐old girl was admitted with a 7‐month history of recurrent fever, weight loss of 5 kg, and general poor health status. Blood culture was positive with Streptococcus viridans. Transthoracic echocardiography established an aneurysm of the root of left subclavian artery, associated with an aortic coarctation just before the origin of the left subclavian artery with a velocity of 4.8 cm/s. Three‐dimensional echocardiography demonstrated the entire inner structure of the aneurysm. Computed tomography reconstruction confirmed the presence of aortic coarctation and mycotic aneurysm, it also revealed an aberrant right subclavian artery.     

Clinical Structural Anatomy of the Inferior Pyramidal Space Reconstructed Within the Cardiac Contour Using Multidetector‐Row Computed Tomography

Although many studies have described the detailed anatomy of the inferior pyramidal space, it may not be easy for cardiologists who have few chances to study cadaveric hearts to understand the correct morphology of the structure. The inferior pyramidal space is the part of extracardiac fibro‐adipose tissue wedging between the 4 cardiac chambers from the diaphragmatic surface of the heart. Many cardiologists have interests in pericardial adipose tissue, but the inferior pyramidal space seems to have been neglected. A number of important structures, including the coronary sinus, atrioventricular node, atrioventricular nodal artery, membranous septum, muscular atrioventricular sandwich (previously called the “muscular atrioventricular septum”), atrial septum, ventricular septum, aortic valvar complex, mitral valvar attachment, and tricuspid valvar attachment are associated with the inferior pyramidal space. We previously revealed its 3‐dimensional live anatomy using multidetector‐row computed tomography. Moreover, the 3‐dimensional understanding of the anatomy in association with the cardiac contour is important from the viewpoints of clinical cardiac electrophysiology. The purpose of this article is to demonstrate extended findings regarding the clinical structural anatomy of the inferior pyramidal space, which was reconstructed in combination with the cardiac contour using multidetector‐row computed tomography, and discuss the clinical implications of the findings.