三维CT技术在牙槽突裂整复中的应用

在牙槽突裂治疗中,影像学评估至关重要,在植骨术前术后常规都会对牙槽突裂患者拍摄X线头颅全景片进行评估,但二维影像存在着影像重叠及模糊等问题。近年来,随着三维CT技术的不断发展,螺旋CT、锥形束CT等技术在121腔医学领域开始广泛应用。在牙槽突裂整复中,三维CT可用于评估术前裂隙大小、植骨术后的效果观察、计算术后植入骨吸收量等,并能以三维重建的方式较为直观地展示裂隙区域。除此之外,与常规螺旋CT相比,锥形束CT还具有价格便宜、辐射量小、清晰度高等优点。     

锥形束CT诊断上颌前牙区多生牙价值研究

目的回顾性分析锥形束CT（CBCT）在上颌前牙区多生牙诊断及定位中的价值。方法以经CBCT确诊为上颌前牙区多生牙的146例患者的195颗多生牙为研究对象,分析多生牙的数目、形态、大小、空间位置、生长方向及其与邻近组织的关系。结果146例患者年龄5~39岁,男女比例为2.95∶1, 其中102例（69.9%）为单颗多生牙。195
颗多生牙的长度平均为（11.97±2.40）mm,其中,126颗（64.6%）位于中线区,131颗（67.2%）为圆锥形,51颗（26.2%）牙根弯曲,98颗（50.3%）牙冠生长方向倒置,133颗（68.2%）与邻近恒牙或恒牙胚有接触,恒牙牙列常伴有各种异常。结论多生牙空间位置变异大,可引起恒牙列病变。CBCT检查能精确直观地显示上颌前牙区多生牙及其与周围组织关系,对多生牙的诊断及定位具有重要的指导意义。     

口腔颌面部异物36例临床分析

目的:探讨口腔颌面部异物伤的诊断与治疗及影像学诊断的重要性。方法 :选择2003-01—2010-12期间收治的,影像和病历资料完善的口腔颌面部异物存留伤36例。分析异物类型,并对临床疗效进行评估。结果:36例异物存留伤患者中,金属异物12例,非金属异物24例。择期异物取出26例;需要急诊清创者10例,而清创术可一期取出异物者6例,4例延期取出。30例经常规X线片检查后,需经CT或三维CT检查进一步定位,评估手术取出的可行性及风险。其中26例经手术取出,4例保留并观察。结论:三维CT在非金属异物存留伤诊疗中起到重要的作用;必须根据异物大小、部位及与周围大血管的毗邻关系,患者全身情况等综合因素判定是否手术及手术时机。     

Evaluation of the efficacy of a prosthodontic stent in determining the position of dental implants

Purpose: To evaluate the efficacy of a dual purpose (diagnostic and surgical) acrylic resin stent with gutta percha marker used in conjunction with 3D imaging in determination of the position and inclination of dental implants. Materials and Methods: This study was performed as a case control study. A total of 41 implants, of which 20 had been placed without the use of stents and 3D imaging (control group) and 21 were placed using stents and 3D imaging (study group), were studied. A diagnostic and surgical stent with radio‐opaque indicator (gutta percha) was fabricated to determine the planned prosthetic position and inclination of the implant. Computed tomography images were obtained and were analyzed using Denta Scan software. The position of the implant was analyzed in mesiodistal and buccolingual dimensions in terms of both position and angulation. SPSS v15.0 was used for statistical analysis (p < 0.05 was considered statistically significant). Results: The study group demonstrated an overall 98.9% efficacy of the test technique being used in the study. On qualitative assessment, the results obtained were within the defined ideal threshold level for four of five parameters (distance from buccal and lingual cortical plate, inter‐implant distance, and buccolingual angulation of the implant relative to underlying alveolar bone). For mesiodistal distance from adjacent teeth, the observation was not above threshold value for only one case. For the control group, the overall efficacy was 66.9%. Conclusion: The technique of combined use of a prosthodontic stent and 3D imaging is an efficacious and better technique in achieving an ideal position of dental implants as compared to conventional techniques using periapical and panoramic radiographs and a cast.     

颞下颌关节弥漫型巨细胞瘤的CT表现

目的:研究发生于颞下颌关节(temporomandibular joint,TMJ)的弥漫型巨细胞瘤的CT影像特点。方法:回顾性分析8例经病理检查证实、发生于TMJ区的弥漫型巨细胞瘤的CT图像。结果:8例中,男女比例为1∶1,平均年龄45.1岁,所有8例病变都表现为膨胀性生长的软组织肿块,且增强后有不同程度的强化。其中,6例肿块密度增高,关节间隙增宽。髁突骨质改变7例,另外6例颞骨关节面骨质破坏并侵犯颅内。结论:发生于TMJ的弥漫型巨细胞瘤的CT影像学特征表现为较高密度的软组织肿块,伴强化,髁突及颅底骨质破坏并侵犯颅内。     

华东地区正常少年儿童舌骨位置变化与年龄及性别的相关性分析

目的:通过测量华东地区不同年龄少年儿童颌面CT上舌骨的位置,研究少年儿童生长发育期间舌骨位置的变化及性别差异.方法:从上海交通大学医学院附属第九人民医院拍摄的(拍摄日期从2009年9月至2010年8月)颌面CT中筛选出281例华东地区少年儿童的CT图像,年龄6～18岁,男141例,女140例.将研究对象根据年龄分为4组,第1组为6～9岁(66例),第2组为10～12岁(62例),第3组为13～15岁(81例),第4组为16～18岁(72例).将CT原始图像数据通过三位图形软件进行三维重建,确定正中矢状面,在正中矢状面上测量舌骨点前后、垂直及相对颅底的位置参数.应用SPSS 16.0软件包中的t检验及线性相关分析对数据进行统计学分析.结果:舌骨前后向及相对颅底的位置在各年龄组均无性别差异.第3组和第4组舌骨垂直向位置有性别差异.男性舌骨前后、垂直向及相对颅底位置和女性舌骨垂直向位置与年龄呈正相关.上、下颌骨的位置与舌骨的位置相关.结论:在儿童期,舌骨位置未表现出性别差异;少年期,男性舌骨位置更低.随着年龄变化,男性舌骨位置表现出更大的变化.上、下颌骨位置影响舌骨的位置.     

Positron emission tomography/computed tomography surveillance in patients with Hodgkin lymphoma in first remission has a low positive predictive value and high costs

Background

The value of performing post-therapy routine surveillance imaging in patients with Hodgkin lymphoma is controversial. This study evaluates the utility of positron emission tomography/computed tomography using 2-[18F]fluoro-2-deoxyglucose for this purpose and in situations with suspected lymphoma relapse.

Design and Methods

We conducted a multicenter retrospective study. Patients with newly diagnosed Hodgkin lymphoma achieving at least a partial remission on first-line therapy were eligible if they received positron emission tomography/computed tomography surveillance during follow-up. Two types of imaging surveillance were analyzed: “routine” when patients showed no signs of relapse at referral to positron emission tomography/computed tomography, and “clinically indicated” when recurrence was suspected.

Results

A total of 211 routine and 88 clinically indicated positron emission tomography/computed tomography studies were performed in 161 patients. In ten of 22 patients with recurrence of Hodgkin lymphoma, routine imaging surveillance was the primary tool for the diagnosis of the relapse. Extranodal disease, interim positron emission tomography-positive lesions and positron emission tomography activity at response evaluation were all associated with a positron emission tomography/computed tomography-diagnosed preclinical relapse. The true positive rates of routine and clinically indicated imaging were 5% and 13%, respectively (P=0.02). The overall positive predictive value and negative predictive value of positron emission tomography/computed tomography were 28% and 100%, respectively. The estimated cost per routine imaging diagnosed relapse was US$ 50,778.

Conclusions

Negative positron emission tomography/computed tomography reliably rules out a relapse. The high false positive rate is, however, an important limitation and a confirmatory biopsy is mandatory for the diagnosis of a relapse. With no proven survival benefit for patients with a pre-clinically diagnosed relapse, the high costs and low positive predictive value make positron emission tomography/computed tomography unsuitable for routine surveillance of patients with Hodgkin lymphoma.     

Minimizing radiation dose for coronary CT angiography

Coronary CT angiography is a rapidly growing technique that offers distinct advantages over traditional imaging techniques. However, because of rapid growth of this technique, radiation dose safety has been placed under the spotlight. There are several main determinants of total radiation dose, and these are outlined in this review. Integration of these dose-saving techniques will go a long way in maintaining diagnostic image quality and improving patient safety.     

Morphology and Variation in Porpoise (Cetacea: Phocoenidae) Cranial Endocasts

Evolution of endocranial anatomy in cetaceans is important from the perspective of echolocation ability, intelligence, social structure, and alternate pathways for circulation to the brain. Apart from the importance of studying brain shape and asymmetries as they relate to aspects of behavior and intelligence, cranial endocasts can show a close correspondence to the hydrostatic shape of the brain in life, and canals and grooves can preserve features of the circulatory system. Multiple samples are rarely available for studies of individual variation, especially in fossils, thus a first step in quantifying variation and making comparisons with fossils is made possible with CT scans of osteological specimens. This study presents a series of high‐resolution X‐ray CT‐derived cranial endocasts of six extant species of Phocoenidae, a clade including some of the smallest and one of the rarest cetaceans. Degree of gyrification varies interspecifically and intraspecifically, possibly resulting from variation in preservation of the ossified meninges. Computed tomographic data show that visually assessed asymmetry in the cranial endocasts is not correlated with volumetric measurements, but nonetheless may reflect torsion in the skull's shape such that the right cerebral and cerebellar hemispheres extend rostrally and laterally more than the left. Vasculature and canals are similar to other described cetacean species, but the hypophyseal casts are unusual. Similarities between brain shape and volume measurements in the different species can be attributed to paedomorphism and concomitant variation in ecological preferences. This may explain similarities Neophocaena phocaenoides and Phocoena sinus share with the juvenile Phocoena phocoena specimen studied. Anat Rec, 296:979–992, 2013. © 2013 Wiley Periodicals, Inc.