胸部の正常CT(肺、胸膜、縦隔、心臓)

胸部の正常CT(肺、胸膜、縦隔、心臓)

胸部の正常CT(肺、胸膜、縦隔、心臓)


イントロダクション

本e-Anatomyモジュールは、通常胸部CT検査に基づく胸部解剖学(肺、胸膜、心臓、大動脈、胸部リンパ節、その他関連する解剖学構造)に特化しています。

日常的な診療実践において放射線科医の方々を支援するために製作されました(例えば、肺区域解剖・肺がんの治療前ステージ分類のためのIASLCリンパ節マップ・TAVRの計画や胸部大動脈瘤経過観察のための胸部大動脈の測定といったトピックを重点的に扱っています)。また本モジュールは、医学生、放射線科・呼吸器科・放射線腫瘍学・胸部外科学分野の研修医の方々が、胸部放射線解剖学について学ぶための教育的ツールとしてもお使いいただけます。

機器と方法

胸部コンピュータ断層撮影は、フランスのIMAIOSの設立者であるAntoine Micheau医師(放射線科医)によって健康な43歳男性に対し実施されました。Siemens Somatom Definition Edgeを用いて以下の技術的条件のもとで行われました。

コリメーション: 128 x 0.6 mm電圧、実効mAs値: 100 kV, 70 eff. mAs
ピッチ: 1.7DLP: 172 mGy cm
スキャン時間 2.5 sCTDIvol: 2.77 mGy
スキャン長: 580 mm実効線量: 2.49 mSv
回転時間: 0.28 s心拍数: 64 bpm

 

ヨード造影剤(オムニパーク[イオヘキソール]350注シリンジ)の注入を行い、心電図同期法(ECG gating)を用いました。

縦隔条件で、冠状断と矢状断のMPR像を利用しました。
一般解剖学、体表解剖学、胸部の骨、胸部の筋、気管と気管支、肺、胸部の血管、胸大動脈、肺動脈、肺静脈、上大静脈を含む胸部の3Dボリュームレンダリング画像を作成しました。
解剖学的ラベリングは、Antoine Micheau医師によってTerminologia Anatomica 2に基づき行われました。
ラベリングの際には、避けられない多少の解剖学的変異を認めました。詳細は以下に記載されています。

 

解剖学的変異と胸部CTの解剖学的ラベリングに関する筆者の注釈:

  • In the lower lobe of the left lung, there is an inconstant subsuperior pulmonary segment that is seen in approximately 30% of individuals, located between the superior and basal segments of the lower lobe. For pedagogical purposes, we included it in the superior segment of right lower lung, but we termed his bronchus as subpsuperior bronchus (S*), and his artery as subsuperior artery (A*).
  • The lower lobe of the right lung has two superior segmental bronchi, with separate origins from the right inferior lobar bronchus.
  • In the lower left lobe, it is not clear if there is a common basal anteromedial segment, or if these segments are separated (this is the option we chose for labeling, but consequently, the anterior segment appears to be slightly lateral and the lateral segment appears to be slightly posterior….).
  • Segmental and subsegmental pulmonary arteries are generally parallel to segmental and subsegmental bronchi and run alongside them. This is in contrast to the course of most pulmonary veins, which run independently of bronchi within interlobular septa. In this module, the segmental arteries were named according to the bronchopulmonary segments that they feed, following the Terminologia Anatomica 2 (we just added the terms interlobar arteries, used in daily practice). However, the proximal portions of the arteries can run independently of their respective bronchi for short segments. Frequently, there are also accessory arteries from neighboring segments, particularly in the right upper lobe. Segmental and subsegmental pulmonary arteries vary considerably in the location of their origins, in whether they arise as common trunks with other arteries or as separate arteries, and in their number. Here are the variations encountered in this e-Anatomy module:

        - There is an additional segmental middle lobar artery, draining the upper lateral part of middle lobe, and connected directly to the left lower lobe artery.
        - There are two separate superior and subsuperior segmental arteries in the right lung.
        - There are at least 3 separate superior segmental arteries in the left lung.

  • In our case, the brachiocephalic artery shares a common origin with the left common carotid artery forming a bovine arch, most common variant of the aortic arch (near 15% population).
  • For the measurements of aortic diameters, we put colored lines as overlay on axial, coronal, sagittal and 3VR, however these landmarks are inevitably imprecise because the measurements of the diameters of the aorta must imperatively be measured on multiplanar reconstructions perpendicular to the aorta (blood flow) and not directly on axial, coronal or frontal images.
  • Some structures like the phrenic nerve along with the pericardiacophrenic artery and vein, or some lymph nodes of the thorax cannot be clearly seen on this CT. But for educational purposes, we put anatomical labels on the presumed place of these structures.
  • The IASLC lymph node map provides a reproducible and consistent set of definitions for the discussion of regional lymphadenopathy in patients with lung cancer. However, because of its comprehensiveness and text-based presentation, it may be challenging to grasp, remember, and apply during daily practice especially on thorax CTs. More importantly, ambiguities may emerge when its definitions are rigorously applied during interpretation of CT images. That’s why we used the article of El-Sherief et al. (Radiographics) for the delimitations of the thoracic lymph node area. The main changes concern the lower boundary of station 1 (thoracic inlet with sagittal oblique plane preferred to the clavicles) and the lower boundary of the station 4 (it should be on the right side of the inferior border of the azygos vein, and on the left side of the superior border of the left main pulmonary artery, but the result is unclear for the precarinal space that is included in station 4 during daily practice.

 

利用可能なコンテンツはありません

  • Kandathil A, Chamarthy M. Pulmonary vascular anatomy & anatomical variants. Cardiovasc Diagn Ther. 2018;8(3):201-207. doi:10.21037/cdt.2018.01.04
  • https://www.med-ed.virginia.edu/courses/rad/CTPA/02anat/anat-02-02.html
  • El-Sherief AH, Lau CT, Wu CC, Drake RL, Abbott GF, Rice TW. International association for the study of lung cancer (IASLC) lymph node map: radiologic review with CT illustration. Radiographics. 2014 Oct;34(6):1680-91. doi: 10.1148/rg.346130097. PMID: 25310423.
  • Terminologia anatomica: international anatomical terminology By the Federative Committee on Anatomical Terminology (FCAT).  Stuttgart:  Georg Thieme Verlag.  ISBN-10: 3-13-114361-4. ISBN-13: 978-3-13-114361-7
  • Netter, Frank H. (2011) Atlas of human anatomy /Philadelphia, PA: Saunders/Elsevier
  • Pocket Atlas of Human Anatomy: 5th edition - W. Dauber, Founded by Heinz Fene