http://dx.doi.org/10.4046/trd.2012.72.1.63 ISSN: 1738-3536(Print)/2005-6184(Online) Tuberc Respir Dis 2012;72:63-67 CopyrightC2012. The Korean Academy of Tuberculosis and Respiratory Diseases. All rights reserved. 이중에너지컴퓨터단층촬영을통해진단된폐의미세혈관종양색전증 울산대학교의과대학서울아산병원 1 내과학교실, 2 호흡기내과학교실, 3 진단방사선학교실 Case Report 옥태진 1, 조민수 1, 장선주 1, 박한승 1, 박환성 1, 박세정 1, 윤신교 1, 이호수 1, 백충희 1, 김광운 1, 김달용 1, 홍윤기 2, 서준범 3, 오연목 2 Microvascular Pulmonary Tumor Embolism Detected by Perfusion Images of Dual-Energy Computed Tomography Tae Jin Ok, M.D. 1, Min Soo Cho, M.D. 1, Sun-Joo Jang, M.D. 1, Han-Seung Park, M.D. 1, Hwan Sung Park, M.D. 1, Se Jeong Park, M.D. 1, Shin Kyo Yoon, M.D. 1, Ho-Su Lee, M.D. 1, Chung Hee Baek, M.D. 1, Gwang Un Kim, M.D. 1, Dalyong Kim, M.D. 1, Yoonki Hong, M.D. 2, Joon Beom Seo, M.D., Ph.D. 3, Yeon-Mok Oh, M.D., Ph.D. 2 Departments of 1 Internal Medicine, 2 Pulmonary and Critical Care Medicine, and 3 Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea Although advances in multi-detector computed tomography (CT) technique make it possible to evaluate peripheral subsegmental pulmonary arteries, several studies have reported that small peripheral embolisms may still be missed. Recently, some reports demonstrated that dual-energy CT improved the capability to detect peripheral pulmonary embolism. We report a case of lymphoma presenting as disseminated microvascular pulmonary tumor embolism, detected by perfusion images using dual energy CT. Key Words: Neoplasm; Pulmonary embolism; Tomography, X-Ray Computed 서 폐동맥전산화단층혈관촬영술 (computed tomographic angiography, CTA) 은폐색전증의진단에표준적인영상학적검사로알려져있다. 최근다중검출기전산화단층촬영 (multi-detector computed tomography) 기술의발전으로말초세분엽혈관까지확인이가능해졌으나, 여전히미세혈관의폐색전을놓칠가능성이있다 1. 최근이중에너지단층촬영술 (dual energy computed tomography, DECT) 이일반적인폐동맥단층혈관촬영술에서 Address for correspondence: Yeon-Mok Oh, M.D., Ph.D. Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Poongnab2-dong, Songpa-gu, Seoul 138-736, Korea Phone: 82-2-3010-3136, Fax: 82-2-3010-6968 E-mail: ymoh55@amc.seoul.kr Received: Aug. 25, 2011 Revised: Sep. 2, 2011 Accepted: Sep. 26, 2011 론 발견되지않은미세혈관폐색전을찾는데도움이된다는보고들이있다 2,3. 저자들은폐혈관CTA에서는관찰되지않았으나 DECT 를통해확인된폐의파종성미세혈관종양색전증 (disseminated microvascular pulmonary tumor embolism, DMPTE) 을진단하여보고하는바이다. 증례환자 : 남자, 71세주소 : 호흡곤란과거력및현병력 : 본환자는 1개월전부터발생한호흡곤란과저산소증을주소로본원으로전원되었다. 이전에다른병력이없던환자로, 내원 1개월전부터서서히미열과전신쇠약감, 호흡곤란이발생하여내원 2주전외부병원에서폐렴또는폐색전증을의심하여경험적치료와검사를진행하였다. 외부병원내원당시 Wells score 상 low probability 였으며 D-dimer는 6.8μg/mL로증가되어있었다. 흉부CTA 와심부정맥혈전증에대한검사에서혈 63
TJ Ok et al: Microvascular pulmonary tumor embolism detected by dual-energy computed tomography 전의증거를찾지는못하였으나폐환기 / 관류스캔에서는양폐에다발성의환기 / 관류불균형이관찰되었다. 2주간의경험적인항응고치료에도불구하고점차심해지는호흡곤란과저산소증 ( 대기중동맥혈산소분압 55 60 mm Hg) 에대한진단과치료를위해본원에입원하였다. 가족력 : 특이사항없었다. 개인력 : 50갑년의흡연력이있었으며 1개월전에중단하였다. 진찰소견 : 혈압은 125/75 mm Hg, 맥박수 68회 / 분, 호흡수 20회 / 분, 체온 36.4 o C였다. 환자는만성병색소견을보였고, 전폐의시진, 청진, 타진, 촉진시특이사항은없었다. 양다리에부종및압통은관찰되지않았으며기타신체검진상의특이소견은없었다. 검사소견 : 일반혈액검사는백혈구 3,000/mm 3, 혈색소 9.4 g/dl, 혈소판 78,000/mm 3 으로범혈구감소증을보 였다. 혈청생화학검사는혈청총단백및알부민이각각 5.8 g/dl와 2.7 g/dl, aspartate aminotransferase 45 IU/L, alanine aminotransferase 53 IU/L, alkaline phosphatase 54 IU/L였다. 본원내원당시 D-dimer는 0.48μg/mL로정상범위였다. 대기중에서동맥혈가스분석결과는 ph 7.46, pco2 33.0 mm Hg, po2 60.0 mm Hg, bicarbonate 24 mm Hg였다. 영상소견 : 외부병원에서시행한단순흉부방사선사진에서는특별한이상소견을관찰할수없었다 (Figure 1). 폐동맥CTA에서도폐동맥색전의증거를찾을수없었으며, 폐실질내의특이소견도보이지않았다 (Figure 2). 폐환기 / 관류스캔상에서는양측폐의다발성관류결손을확인할수있었다 (Figure 3). 임상경과 : 입원후시행한심초음파에서삼첨판역류의속도는 3.3 m/s였으며폐환기 / 관류스캔, 폐동맥CTA에서는이전의검사들과변화가없었다. Wells score가낮고, 심부정맥혈전증의증거가없으며폐동맥CTA 에서도 Figure 1. Chest X-ray on admission revelaed no remarkable lesion despite hypoxemia. Figure 2. No tumor or thromboemboli was observed on the initial pulmonary computed tomographic angiography. Figure 3. Multiple ventilation/perfusion mismatching lesions were seen in both lung fields. 64
Tuberculosis and Respiratory Diseases Vol. 72. No. 1, Jan. 2012 Figure 4. Dual energy computed tomography showed a perfusion defect (marked with asterisk) in both sides of the lung field (left). The PET scan revealed a high FDG uptake in similar sites (right). PET: positron emission tomography. 고 찰 Figure 5. 18-FDG PET indicated a hypermetabolic lesion in the bone marrow. 색전이발견되지않아폐색전증으로진단하기힘든상태였다. 이에 DECT 를시행하여양측폐야에다발성조영제로조영이잘되지않는부분을확인하였으며, 이는핵의학검사에서의환기 / 관류불일치와일치하였다 (Figure 4). 폐색전증및환자의범혈구감소증과미열에대해숨은악성종양의가능성을배제하기위해 F-18 FDG를사용한전신양전자방출단층촬영술 (positron emission tomography, PET) 을시행하였으며, 전신의골수에 FDG 섭취증가소견이보였다 (Figure 5). 또한, 양측말초폐실질에도미만성의 FDG 섭취증가가관찰되었다. 저자들은이환자를혈액암에의한폐의파종성미세혈관종양색전증으로잠정진단하였다. 환자는이후골수검사에서 B-cell 림프종이진단되었으며항암치료를시행하였다. DMPTE 는악성종양을가진환자에서발생하는호흡곤란과저산소증의드문원인중하나로, 유방, 위, 폐등에서기원하는경우가많다 4. 이질환은일반흉부방사선사진이나, 특히폐색전의표준적진단도구인흉부CTA 등에서특별한소견이없어진단이어렵다 5. 이전연구들에서는환기 / 관류스캔이 DMPTE 의진단적가치를가지고있음을보고한바있다 6. 그러나 DMPTE 환자들은저산소증상태인경우가많아검사시간이비교적오래걸리는환기 / 관류스캔을시행하기가힘들고, macroalbumin 을사용한관류스캔이심각한저산소증을일으킨증례가보고된바있어안전성에문제가있다 7,8. 진단의정확성면에서도, 임상적으로폐색전확률이낮은환자에서는환기 / 관류스캔의진단의정확도가떨어진다 9. 따라서보다정확하면서도신속하고안전하게 DMPTE를진단할수있는진단기법이필요하다. Dual-energy technique 을사용한 DECT 는영상내에서요오드성분을직접적으로검출하여폐관류를반영하는요오드분포를직접볼수있다 10. 최근 Lee 등 3 의연구에서는기존 CTA에 DECT 를추가하여세분엽이하의미세혈관폐색전진단의민감도를올릴수있었다. 또한 Chae 등 2 의연구에서는 DECT 가폐색전의분포를반영하는 CTA obstruction score 또는 right ventricular-to-left ventricular diameter ratio 등과잘상관됨을보여주었다. 안전성측면에서도 DECT 는일반 CT에비해방사선피폭량이큰차이가없는것으로알려져있다 11. 따라서 DECT 는일반적인폐동맥CTA상폐쇄병변이없는환자들에서추가적인위험이나방사선피폭증가없이폐색전증유무와중증도에대해더많은정보를얻을수있다. 이증례에서는 PET도진단과정에많은도움이되었다. 65
TJ Ok et al: Microvascular pulmonary tumor embolism detected by dual-energy computed tomography PET는이미원발병변을알수없는암환자에서원발병소를찾기위한방법으로잘알려져있다 12. 또한대규모연구에서확인되지는않았으나 PET가종양에의한폐색전환자에서진단에도움이된다는보고들이있다 13. 본증례에서는악성병소의확인을위해 PET가시행되었으며, 골수전체에퍼져있는병소를확인할수있었고, 조직검사의목표를설정할수있었다. 이환자에서는 PET 에서폐실질내에서도 FDG 섭취가높게나타난점은, 특이적이지는않으나조직검사가나오지않은상태에서종양에의한 DMPTE의가능성을뒷받침해주는소견이라고할수있다. 종양에의한폐색전여부를정확하게진단하기위해서는폐의조직검사를통해종양세포를확인해야하지만, 위의사례들과같이환자가심한저산소증상태이며, 방사선학적검사상정상소견인경우가많아현실적으로는조직검사가불가능하여임상적진단을내릴수밖에없는경우가많다 4,5. Liang 등 14 이보고한증례에서는환자가저산소증과호흡곤란으로내원하여급성심장사를일으킨후시행한부검에서미세혈관을막는비소세포성폐암에의한 DMPTE가진단되었다. Georgin-Lavialle 등 15 이보고한증례에서는 CT상에서특이병변은없으나심한저산소증이있는환자로폐색전증의심하에시행한환기 / 관류스캔상에서관류결손을확인하였고피부의결절에서조직검사를시행하여림프종에의한 DMPTE 를진단하였다. 우리환자에서는비록폐조직을검사하지는못했으나, 환자가종양이있다는점을감안해도 Wells score 가낮아혈전에의한폐색전증의가능성이낮고, 임상및초음파소견상심부정맥혈전증의증거가관찰되지않으며, 환자가저산소증이있음에도 CTA 상큰혈전이관찰되지않고, PET 상폐의 FDG 섭취가증가되어있다는점등에서임상적으로혈전보다는종양에의한폐색전증의가능성이높을것으로진단하였다. 또한, DMPTE 는진단이어려울뿐만아니라진단이늦어져원인에대한치료가늦어질경우사망에이를수있는심각한질환이다. 본환자는생명을위협하는저산소증이발생하기전에 DECT 와 PET 를통해 DMPTE 와원발종양을진단할수있었다. 본저자들은암에의한폐색전이의심되는환자에서일반적인방법에더하여 DECT 와전신 PET를시행하는것이진단에큰도움이될수있음을문헌고찰과함께보고하는바이다. 참고문헌 1. Le Gal G, Righini M, Parent F, van Strijen M, Couturaud F. Diagnosis and management of subsegmental pulmonary embolism. J Thromb Haemost 2006;4:724-31. 2. Chae EJ, Seo JB, Jang YM, Krauss B, Lee CW, Lee HJ, et al. Dual-energy CT for assessment of the severity of acute pulmonary embolism: pulmonary perfusion defect score compared with CT angiographic obstruction score and right ventricular/left ventricular diameter ratio. AJR Am J Roentgenol 2010;194:604-10. 3. Lee CW, Seo JB, Song JW, Kim MY, Lee HY, Park YS, et al. Evaluation of computer-aided detection and dual energy software in detection of peripheral pulmonary embolism on dual-energy pulmonary CT angiography. Eur Radiol 2011;21:54-62. 4. Roberts KE, Hamele-Bena D, Saqi A, Stein CA, Cole RP. Pulmonary tumor embolism: a review of the literature. Am J Med 2003;115:228-32. 5. Schriner RW, Ryu JH, Edwards WD. Microscopic pulmonary tumor embolism causing subacute cor pulmonale: a difficult antemortem diagnosis. Mayo Clin Proc 1991;66:143-8. 6. Crane R, Rudd TG, Dail D. Tumor microembolism: pulmonary perfusion pattern. J Nucl Med 1984;25:877-80. 7. Chakeres DW, Spiegel PK. Fatal pulmonary hypertension secondary to intravascular metastatic tumor emboli. AJR Am J Roentgenol 1982;139:997-1000. 8. Child JS, Wolfe JD, Tashkin D, Nakano F. Fatal lung scan in a case of pulmonary hypertension due to obliterative pulmonary vascular disease. Chest 1975;67: 308-10. 9. Value of the ventilation/perfusion scan in acute pulmonary embolism. Results of the prospective investigation of pulmonary embolism diagnosis (PIOPED). The PIOPED Investigators. JAMA 1990;263:2753-9. 10. Sadigh G, Kelly AM, Cronin P. Challenges, controversies, and hot topics in pulmonary embolism imaging. AJR Am J Roentgenol 2011;196:497-515. 11. Hoey ET, Gopalan D, Ganesh V, Agrawal SK, Qureshi N, Tasker AD, et al. Dual-energy CT pulmonary angiography: a novel technique for assessing acute and chronic pulmonary thromboembolism. Clin Radiol 2009; 64:414-9. 12. Sève P, Billotey C, Broussolle C, Dumontet C, Mackey JR. The role of 2-deoxy-2-[F-18]fluoro-D-glucose positron emission tomography in disseminated carcinoma of unknown primary site. Cancer 2007;109:292-9. 13. Sone T, Yoshikawa K, Fukunaga M. Pulmonary tumor 66
Tuberculosis and Respiratory Diseases Vol. 72. No. 1, Jan. 2012 embolism from choriocarcinoma: detection with F-18 FDG positron emission tomography. Clin Nucl Med 2008;33:773-4. 14. Liang YH, Kuo SW, Lin YL, Chang YL. Disseminated microvascular pulmonary tumor embolism from nonsmall cell lung cancer leading to pulmonary hypertension followed by sudden cardiac arrest. Lung Cancer 2011;72:132-5. 15. Georgin-Lavialle S, Darmon M, Galicier L, Fysekidis M, Azoulay E. Intravascular lymphoma presenting as a specific pulmonary embolism and acute respiratory failure: a case report. J Med Case Reports 2009;3:7253. 67