Cone-beam computed tomography evaluation of palatogingival grooves: a retrospective study with literature review

Objectives

The purpose of the present study was to radiographically evaluate the prevalence and characteristics of palatogingival grooves (PGs) in maxillary anterior teeth on cone-beam computed tomography (CBCT) to better understand the nature of these defects.

Methods

The CBCT examinations of 993 teeth (330 canines, 315 lateral incisors, 348 central incisors) in 191 patients (87 males, 104 females; age range 16–80 years) were evaluated retrospectively. The diagnosis and radiographic condition of PGs were obtained by consensus among all observers. Verification of PGs was achieved from the patients’ clinical records, which were stored in a database after their clinical evaluation. Differences in age, sex, occurrence, and location were evaluated by the Chi-square test. The level of significance was set at p < 0.05.

Results

Among the 993 teeth examined, nine PGs were observed in seven lateral incisors and two central incisors in eight patients (four males and four females). There was one bilateral case in the lateral incisors. The frequencies of PG occurrence and affected patients were 0.90 and 4.18%, respectively, without significance for sex and location (p > 0.05).

Conclusions

PGs were a relatively infrequent anomaly of teeth in this population, but when present, clinicians should understand the clinical features of these root variations.

     

High-resolution spiral CT of the breast at very low dose: concept and feasibility considerations

Objective  

Mammography, today’s standard imaging approach, has deficits with respect to the superimposition of anatomical structures. Dedicated CT of the breast so far indicated that it can provide superior soft-tissue imaging, but that it still has significant limitations with respect to spatial resolution and dose. We have assessed novel dedicated breast CT technology.     

机器人辅助腹腔镜下根治性膀胱切除加尿流改道术的临床分析

目的 探讨采用da Vinci S机器人系统完成机器人辅助腹腔镜下根治性膀胱切除(robotic-assisted laparoscopic radical cystectomy,RARC)加尿流改道术的临床可行性,并总结技术特点和临床效果. 方法 2007年12月至2012年3月膀胱尿路上皮癌患者22例,男20例,女2例.年龄37～ 72岁,平均62岁.体质指数22.5 ～ 30.1 kg/m2,平均26.1 kg/m2.麻醉评分1～2分.术前肿瘤活检病理诊断为浸润性或高危的非肌层浸润性膀胱尿路上皮痛,术前检查均未发现有其他邻近脏器浸润、盆腔淋巴结转移或远处转移,临床分期均低于T2N0M0.全麻下行RARC加尿流改道术,其中行体外尿流改道术15例(原位新膀胱2例,回肠膀胱术13例),行完全腹腔镜下尿流改道术7例(回肠膀胱术2例,原位新膀胱5例). 结果 本组22例手术均获得成功.手术时间300 ～ 667 min,平均480 min;出血量100 ～ 1200 ml,平均550 ml;淋巴结清扫数目6～ 25枚,平均15枚.术后2～3d下地活动,3～4d肠功能恢复,术后住院时间8～35 d,平均16d.行原位新膀胱的患者术后1个月行膀胱造影确定无吻合口漏后拔除尿管和双侧输尿管支架管.术后随访4 ～ 49个月,平均32个月,复发2例,死亡1例,出现肾积水2例,其余病例肾功能均正常,尿控较满意. 结论 根据初期的手术操作过程和随访结果,RARC加尿流改道术在临床上是可行的.更多的操作经验、长期和随机的对照研究将有助于对这一技术进行评估和推广.     

Achieving routine submillisievert CT scanning: report from the summit on management of radiation dose in CT

This Special Report presents the consensus of the Summit on Management of Radiation Dose in Computed Tomography (CT) (held in February 2011), which brought together participants from academia, clinical practice, industry, and regulatory and funding agencies to identify the steps required to reduce the effective dose from routine CT examinations to less than 1 mSv. The most promising technologies and methods discussed at the summit include innovations and developments in x-ray sources; detectors; and image reconstruction, noise reduction, and postprocessing algorithms. Access to raw projection data and standard data sets for algorithm validation and optimization is a clear need, as is the need for new, clinically relevant metrics of image quality and diagnostic performance. Current commercially available techniques such as automatic exposure control, optimization of tube potential, beam-shaping filters, and dynamic z-axis collimators are important, and education to successfully implement these methods routinely is critically needed. Other methods that are just becoming widely available, such as iterative reconstruction, noise reduction, and postprocessing algorithms, will also have an important role. Together, these existing techniques can reduce dose by a factor of two to four. Technical advances that show considerable promise for additional dose reduction but are several years or more from commercial availability include compressed sensing, volume of interest and interior tomography techniques, and photon-counting detectors. This report offers a strategic roadmap for the CT user and research and manufacturer communities toward routinely achieving effective doses of less than 1 mSv, which is well below the average annual dose from naturally occurring sources of radiation.     

Volume-of-Interest Imaging of the Inner Ear in a Human Temporal Bone Specimen Using a Robot- Driven C-Arm Flat Panel Detector CT System

SUMMARY: VOI imaging can provide higher image quality at a reduced dose for a subregion. In this study with a robot-driven C-arm FDCT system, the goals were proof of feasibility for inner ear imaging, higher flexibility during data acquisition, and easier processing during reconstruction. First a low-dose OV scan was acquired allowing an orientation and enabling the selection of the VOI. The C-arm was then moved by the robotic system without a need for patient movement and the VOI was scanned with adapted parameters. Uncompromised artifact-free image quality was achieved by the 2-scan approach and the dose was reduced by 80%-90% in comparison with conventional MSCT and FPCT scans.     

颅底外面枕骨基底部及周边骨性结构的测量和临床意义

目的为斜坡区肿瘤手术提供解剖资料。方法20例整颅,10例行水平切面,10例行正中矢状切面。测量切牙孔、前鼻棘、后鼻棘、枕骨大孔前端、枕髁前端、卵圆孔、破裂孔、颈动脉管外口及舌下神经管外口的内侧缘至咽结节的距离;测量卵圆孔、破裂孔、颈动脉管外口及舌下神经管外口的内侧缘至正中线的距离;测量枕骨基底部颅底外面的长径、枕骨大孔纵径(FML)、枕骨大孔前正中点与枕髁后缘连线垂直距离(AOCP)、枕髁轴径(OCA)、枕髁间距。结果切牙孔后缘、前鼻棘、后鼻棘、枕骨大孔前端、枕髁前端、卵圆孔、破裂孔、颈动脉管外口及舌下神经管外口的内侧缘至咽结节的距离分别为(mm):72.12±4.25、77.77±3.89、33.73±2.07、13.14±1.91、15.71±1.74、27.51±2.12、15.98±1.98、25.93±2.23、19.15±1.49。卵圆孔、破裂孔、颈动脉管及舌下神经管外口的内侧缘至中线的距离分别为:25.55±1.63、11.72±1.70、25.75±1.98、17.41±1.41。枕骨基底部颅底外面长径、FML、AOCP、OCA、枕髁间距分别为(mm):28.80±2.67、35.84±2.59、17.10±1.13、24.55±2.35、21.07±1.92。结论经口咽至斜坡区的手术入路中,开骨窗时安全范围是以咽结节为中心,以15mm为半径做斜坡磨除;也可以做矩形骨窗,即以咽结节为中心开一长(高)25mm×宽20mm的骨窗。