Service d'ORL, hôpital Purpan, CHU de Toulouse, place du Dr-Baylac, 31059 Toulouse cedex 9, France.
Eur Ann Otorhinolaryngol Head Neck Dis. 2011 Nov;128(5):230-5. doi: 10.1016/j.anorl.2011.02.016. Epub 2011 Oct 19.
High-resolution CT imaging is essential to diagnosis and follow-up of temporal bone pathology. Morphologically, CT is the reference examination. The requirement of long-term follow-up thus exposes patients to cumulative radiation doses. Limiting exposure to ionizing radiation is an increasing concern of public health authorities. The principal advantage of Cone Beam CT (CBCT) lies in a significant reduction in radiation dose. The main objective of the present study was to assess the morphologic concordance between CBCT and Multislice Helical Computed Tomography (MSCT) on 20 anatomic landmarks corresponding to regions of interest in clinical practice. The secondary objectives were to compare the two techniques qualitatively in stapes and footplate assessment and measurement of footplate thickness, and quantitatively in terms of dosimetry.
An experimental anatomical study was performed on 12 temporal bones from fresh human cadavers of unknown clinical history. Each underwent CBCT and MSCT.
There was no significant difference in morphologic assessment of the temporal bones on the two techniques. Exploration of the stapes, incudostapedial joint, anterior stapediovestibular joint and footplate was qualitatively more precise on CBCT, and footplate thickness showed less overestimation than on MSCT. CBCT delivered 22 times less radiation than MSCT under the present experimental conditions.
CBCT provides reliable morphologic assessment of temporal bone, thanks to higher spatial resolution than on MSCT, with significantly reduced radiation dose.
高分辨率 CT 成像对于诊断和随访颞骨病变至关重要。从形态学上看，CT 是参考检查。因此，长期随访的要求使患者暴露于累积辐射剂量下。限制电离辐射的暴露是公共卫生当局日益关注的问题。锥形束 CT（CBCT）的主要优势在于显著降低了辐射剂量。本研究的主要目的是评估 20 个解剖学标志（对应于临床实践中的感兴趣区域）的 CBCT 与多层螺旋 CT（MSCT）之间的形态学一致性。次要目标是定性比较两种技术在评估镫骨和镫骨底板以及测量底板厚度方面的差异，并在剂量学方面进行定量比较。
对 12 个来自无临床病史的新鲜人尸颞骨进行了实验性解剖研究。每个颞骨都接受了 CBCT 和 MSCT 检查。
两种技术对颞骨的形态评估没有显著差异。在 CBCT 上，对镫骨、砧镫关节、前砧镫关节和底板的探查更为精确，且底板厚度的高估程度小于 MSCT。在本实验条件下，CBCT 的辐射量比 MSCT 少 22 倍。
由于 CBCT 的空间分辨率高于 MSCT，因此可以提供可靠的颞骨形态评估，同时显著降低了辐射剂量。
