肺部CTA可以分辨肺栓塞之外的狀況

作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　August 31, 2009 — 根據9月份美國放射學期刊(American Journal of Roentgenology)的研究結果，孩童的肺部電腦斷層血管攝影(computed tomography angiography，CTA)，可以分辨肺栓塞(pulmonary embolism，PE)之外的狀況，包括骨折和心臟病。
　　
　　第一作者、哈佛醫學院、兒童醫院的Edward Y. Lee醫師在新聞稿中表示，CTA最重要的好處之一，是在無肺栓塞證據下，顯示出孩童與成人病患之其他診斷的能力。
　　
　　該研究使用波士頓兒童醫院的資訊系統進行研究，目標在於評估臨床懷疑但排除PE孩童之其他診斷的類型和頻率。對於臨床懷疑PE、在2004年7月至2008年3月進行肺部CTA的所有小兒病患(18歲以下)，由兩位有經驗的小兒放射專家回顧他們的肺部CTA檢查結果。這些放射專家系統性回顧無PE證據之89名病患的96件診斷品質的肺部CTA檢查，尋找肺部、縱膈、呼吸道、心血管系統、肋膜以及骨骼等可能的其他診斷。
　　
　　CTA顯示沒有PE的89名孩童中，28人是男孩、61名女孩；34個住院病患以及62名門診病患；平均年紀為13.4 ± 4.7歲(年齡範圍：2個月–18歲)。沒有PE證據的96件肺部CTA檢查中，39 (41%)件顯示正常結果，其他57件(59%)檢查有其他診斷：包括22件肺炎、22件肺萎陷、3件惡性疾病。
　　
　　沒有PE證據的每件CTA檢查中，顯示有先天心臟病、肺高壓、心包膜積水，也顯示有肺結節、肋骨骨折、右心房血栓、脂肪栓塞。
　　
　　17名病患顯示與現有異常有關的肋膜積水，包括8例肺炎、8例肺萎陷、1例肋骨骨折。
　　
　　Lee醫師表示，最常見的兩個其他診斷是肺炎與肺萎陷。不過，在整個胸腔，有多種其他診斷，包括先天心臟病、肺高壓、肋骨骨折等等。CTA的最重要好處在於，在無肺栓塞證據下，顯示出孩童與成人病患之其他診斷的能力。
　　
　　研究限制包括屬於回溯設計，未適當評估心臟內的結構、缺乏與傳統肺血管攝影的關聯、對於認為的其他診斷缺乏確定性的標準參考檢查。此外，研究對象是大型4級兒童醫院的病患，而限制了一般性，且研究結果有一些重覆，因為3個病患有1次以上的CTA檢查。
　　
　　Lee醫師結論表示，我們的發現強調，當解釋孩童肺部CTA檢查時，肺動脈之外其他系統性研究的重要性。
　　  

Pulmonary CTA May Identify Conditions Other Than Pulmonary Embolism

By Laurie Barclay, MD
Medscape Medical News

August 31, 2009 — Pulmonary computed tomography angiography (CTA) in children can identify conditions other than pulmonary embolism (PE), including fractures and heart disease, according to the results of a study reported in the September issue of the American Journal of Roentgenology.

"One of the most important advantages of CTA is its ability to show alternative diagnoses in pediatric and adult patients without evidence of pulmonary embolism," lead author Edward Y. Lee, MD, MPH, from Children's Hospital Boston and Harvard Medical School in Boston, Massachusetts, said in a news release.

The goal of this study was to assess the frequency and types of alternative diagnoses identified in children with clinically suspected but excluded PE, with use of the Children's Hospital Boston information system. For all consecutive pediatric patients (< 18 years old) with clinically suspected PE who had pulmonary CTA from July 2004 to March 2008, two experienced pediatric radiologists reviewed their pulmonary CTA studies. These radiologists systematically reviewed 96 diagnostic-quality pulmonary CTA studies without evidence of PE from 89 patients, looking for a possible alternative diagnosis in the lungs, mediastinum, central airways, cardiovascular system, pleura, and skeleton.

Of the 89 children without CTA evidence of PE, 28 were boys and 61 were girls; 34 were inpatients and 62 were outpatients; and mean age was 13.4 ± 4.7 years (age range, 2 months - 18 years). Of the 96 pulmonary CTA studies without evidence of PE, 39 (41%) showed normal results, and the remaining 57 studies (59%) had alternative diagnoses. These were pneumonia in 22, atelectasis in 22, and malignant disease in 3 studies.

Each of the pulmonary CTA studies without evidence of PE showed congenital heart disease, pulmonary hypertension, and pericardial effusion, and 1 each showed pulmonary nodules, rib fractures, right atrial thrombus, and fat embolism.

Pleural effusions associated with coexisting abnormalities were present in 17 patients, including 8 with pneumonia, 8 with atelectasis, and 1 with rib fractures.

"The two most common alternative diagnoses were pneumonia and atelectasis," Dr. Lee said. "However, a variety of other alternative diagnoses, including congenital heart disease, pulmonary hypertension, rib fractures, and more, were identified throughout the thorax....One of the most important advantages of CTA is its ability to show alternative diagnoses in pediatric and adult patients without evidence of pulmonary embolism."

Limitations of this study include retrospective design, suboptimal evaluation of intracardiac structures, lack of correlation with conventional pulmonary angiography, and lack of confirmatory standard reference tests for all the suggested alternative diagnoses. In addition, the setting in a large tertiary children's hospital limited generalizability, and there was slight duplication of results because 3 patients had more than 1 pulmonary CTA study,

"Our findings emphasize the importance of systemically searching beyond the pulmonary arteries for an alternative diagnosis when interpreting pulmonary CTA studies in children," Dr. Lee concluded.

AJR Am J Roentgenol. 2009;193:888-894.