エコーでの大腿直筋の筋肉量評価

超音波エコーによる大腿直筋の筋肉量評価の信頼性と妥当性に関する論文を紹介します。

Tom Thomaes, et al: Reliability and validity of the ultrasound technique to measure the rectus femoris muscle diameter in older CAD-patients. BMC Medical Imaging 2012, 12:7 doi:10.1186/1471-2342-12-7

下記のHPで全文見ることができます。

http://www.biomedcentral.com/content/pdf/1471-2342-12-7.pdf

サルコペニアの診断で筋肉量減少の評価は必須ですが、DEXA、BIA、CT、MRIによる評価は容易ではありません。そこで超音波エコーとCTを比較して、大腿直筋の筋肉量評価の信頼性と妥当性を検証しています。

結果ですが、超音波エコーによる大腿直筋の筋肉量評価は信頼性（2回の測定）、妥当性（CTとの比較）とも良好でした。今回は高齢冠動脈疾患患者のみを対象としていますが、おそらく他の疾患の高齢者に対しても、超音波エコーによる筋肉量評価は有用だと考えます。

超音波エコーによる大腿直筋の筋肉量評価は、他の方法に比べると簡易で在宅でも評価可能ですが、それでも機械がないとできません。その場合には、大腿直筋の触診だけでも有用です。侵襲後や悪液質によるサルコペニアの方では、大腿直筋の筋萎縮が著明です。大腿四頭筋のMMTと一緒に評価するとよいと思います。

Abstract
Background
The increasing age of coronary artery disease (CAD) patients and the occurrence of
sarcopenia in the elderly population accompanied by ‘fear of moving’ and hospitalization in
these patients often results in a substantial loss of skeletal muscle mass and muscle strength.
Cardiac rehabilitation can improve exercise tolerance and muscle strength in CAD patients
but less data describe eventual morphological muscular changes possibly by more difficult
access to imaging techniques. Therefore the aim of this study is to assess and quantify the
reliability and validity of an easy applicable method, the ultrasound (US) technique, to
measure the diameter of rectus femoris muscle in comparison to the muscle dimensions
measured with CT scans.
Methods
45 older CAD patients without cardiac event during the last 9 months were included in this
study. 25 patients were tested twice with ultrasound with a two day interval to assess testretest
reliability and 20 patients were tested twice (once with US and once with CT) on the
same day to assess the validity of the US technique compared to CT as the gold standard.
Isometric and isokinetic muscle testing was performed to test potential zero-order
correlations between muscle diameter, muscle volume and muscle force.
Results
An intraclass correlation coefficient (ICC) of 0.97 ((95%CL: 0.92 – 0.99) was found for the
test-retest reliability of US and the ICC computed between US and CT was 0.92 (95%CL:
0.81 – 0.97). The absolute difference between both techniques was 0.01 ± 0.12 cm (p = 0.66)
resulting in a typical percentage error of 4.4%. Significant zero-order correlations were found
between local muscle volume and muscle diameter assessed with CT (r = 0.67, p = 0.001) and
assessed with US (r = 0.49, p < 0.05). Muscle strength parameters were also significantly
correlated with muscle diameter assessed with both techniques (range r = 0.45-r = 0.61,
p < 0.05).
Conclusions
Ultrasound imaging can be used as a valid and reliable measurement tool to assess the rectus
femoris muscle diameter in older CAD patients.