二次喫煙の　害を示した　ＭＲＩ

Special MRI Shows Secondhand Smoke Damages Lungs
Researchers say their study is the first to prove a connection

December 10, 2007

MONDAY, Nov. 26 (HealthDay News) -- Using a special type of magnetic resonance imaging (MRI), U.S. researchers have identified structural damage to the lungs caused by secondhand smoke. This is the first study to produce evidence of such a link, they added. "It's long been hypothesized that prolonged exposure to secondhand smoke may cause physical damage to the lungs, but previous methods of analyzing lung changes were not sensitive enough to detect it," Chengbo Wang, magnetic resonance physicist at The Children's Hospital of Philadelphia, said in a prepared statement. Wang's team used long-time-scale, global helium-3 diffusion MRI to study the lungs of seven current and former smokers and 36 people who'd never smoked. Of those 36 people, 18 had a high level of secondhand smoke exposure. The results showed that 57 percent of smokers and 33 percent of the nonsmokers with high exposure to secondhand smoke appeared to have early signs of lung damage. In addition, 14 percent of smokers and 67 percent of nonsmokers with high exposure to secondhand smoke showed evidence of developing respiratory problems such as asthma or chronic bronchitis. "These findings suggest that breathing secondhand smoke can injure your lungs," Wang said. "Since legislation to limit public exposure to secondhand smoke is still being considered in many states, we hope that our work can be used to add momentum to the drive to pass such legislation." The study was slated to be presented Monday at the Radiological Society of North America annual meeting, in Chicago.

特殊な磁気共鳴画像法（MRI）を使用することにより、受動喫煙による肺の構造的損傷が初めて明確に示され、米シカゴで開かれた北米放射線学会（RSNA）年次集会で発表された。 　長期間の受動喫煙への曝露が肺に物理的な損傷をもたらすとの仮説は以前からあったものの、これまでの分析方法では感度が不十分なため確認することができなかったと、発表者の米フィラデルフィア小児病院（ペンシルベニア州）のChengbo Wang氏は述べている。 　Wang氏らは、「long-time-scale, global helium-3 diffusion MRI」（長期スケール包括的ヘリウム-3拡散MRI）と呼ばれる技術を用いて、現喫煙者および元喫煙者7人、非喫煙者36人（このうち18人は高レベルの受動喫煙に曝露）の肺を調べた。その結果、喫煙者の57％、受動喫煙レベルの高い非喫煙者の33％に肺損傷の初期徴候がみられた。さらに、喫煙者の14％、受動喫煙レベルの高い非喫煙者の67％に、喘息や慢性気管支炎などの呼吸器障害の発症が認められた。 　この結果は、受動喫煙が肺を損傷することを示すという。公共の場での受動喫煙を防止するための法案が米国の多くの州で検討されており、今回の研究がこのような法案通過を促すきっかけとなるよう期待すると、Wang氏は述べている。（