Amac: Bu calismanin amaci, entegre pozitron emisyon tomografisibilgisayarli tomografi (PET-BT) ve endobronsiyal ultrasonografi rehberliginde yapilan transbronsiyal igne aspirasyonunun (EBUS-TBIA) malign mediastinal/hiler lenf nodlarinin tanisindaki duyarliligi, ozgullugu ve tani degerini saptamak ve birbirleri ile kiyaslamaktir. Calisma plani: Ekim 2008 Nisan 2011 tarihleri arasinda bilinen primer malignitesi veya malignite suphesi olup, bilgisayarli toraks tomografisinde buyumus ve PET-BT’de hipermetabolik hiler/mediastinal lenfnodu saptanan ve sitolojik tani icin EBUS-TBIA yapilmis 131 olgunun (96 erkek, 35 kadin; ort. yas 58.3±8.4 yil; dagilim 42-75) dosyasi retrospektif olarak incelendi. EBUS-TBIA ile kesin tani konulamayan olgulara mediastinoskopi/video yardimli torakoskopik cerrahi (VYTC) gibi daha invazif girisimler uygulandi. PET-BT’de malignite icin standart maksimum alim (SUDmax) sinir degeri ≥3.0 olarak belirlendi. Malign mediastinal/hiler lenf nodlarinin tanisinda PET-BT ve EBUS-TBIA’nin duyarlilik, ozgulluk, tani degeri ve negatif ve pozitif ongordurucu degerleri hesaplandi. Sonuclar birbirleri ile karsilastirildi. Bul gu lar: Toplam 131 hastada 191 lenf nodu istasyonundan aspirasyon yapildi. Yuz kirk iki malign lenf nodundan 134’une EBUS-TBIA ile malignite tanisi konulurken, 127’sinin PET-BT’de SUDmax degerinin ≥3.0 oldugu goruldu. EBUS-TBIA ve PET-BT’nin malign mediastinal ve hiler lenf nodlarinin tanisindaki duyarlilik, ozgulluk, tani degeri ve negatif ve pozitif ongordurucu degerleri sirasiyla %94.3, %100, %95.8, %85.9, %100 ve %89.4, %18.3, %71.2, %37.5, %76.0 idi. EBUS-TBIA ve PET-BT’nin birlikte kullanimi ile duyarlilik %100’e ulasti. Sonuc: EBUS-TBIA’nin duyarlilik, ozgulluk, tani dogrulugu ve negatif ongordurucu degeri ve pozitif ongordurucu degeri PET-BT’den daha yuksektir. Klasik bilgilere gore PET-BT’nin yanlis pozitiflik oraninin yuksek olmasi nedeni ile mediastinal evrelemede histolojik dogrulamasinin yapilmasi gerekmektedir. EBUS-TBIA, PET-BT pozitif mediastinal/hiler lenf nodlarinin histolojik dogrulamasinda etkin, guvenilir ve minimal invasiv bir yontemdir. Anah tar soz cuk ler: Endonronsiyal ultrasonografi; ince igne aspirasyonu; akciger kanseri; lenf nodu; pozitron emisyon tomografisi-bilgisayarli tomografi; evreleme. Background:In this study, we aimed to identify the sensitivity, specificity and diagnostic accuracy of integrated positron emission tomographycomputed tomography (PET-CT) and endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in the diagnosis of malignant mediastinal/hilar lymph nodes and to compare with each other. Methods: Records of 131 patients (96 males, 35 females; mean age 58.3±8.4 years; range 42 to 75 years) with known primary or suspected malignancy who had enlarged and hypermetabolic hilar/mediastinal lymph nodes detected by thoracic CT and at PET-CT and in whom EBUS-TBNA performed for cytologic confirmation of the malignancy between October 2008 and April 2011 were retrospectively analyzed. More invasive procedures including mediastinoscopy/video-assisted thoracoscopic surgery (VATS) were performed in patients who did not receive definite diagnosis using EBUSTBNA. The maximum standardised uptake value (SUVmax) cut-off level of PET-CT was considered ≥3.0. The sensitivity, specificity, diagnostic accuracy, and negative and positive predictive values of PET-CT and EBUS-TBNA in diagnosis of malignant hilar/mediastinal lymph nodes were calculated. The results were compared with each other. Results:A total of 191 lymph node stations of 131 patients were aspirated from the LN stations. Of the 142 lymph nodes, 134 were diagnosed with malignancy using EBUS-TBNA, while SUVmax value was ≥3.0 in 127 by PET-CT. The sensitivity, spesificity, diagnostic accuracy, and negative and positive predictive values of EBUS-TBNA and PET-CT were 94.3%, 100%, 95.8%, 85.9%, 100% and 89.4%, 18.3%, 71.2%, 37.5%, 76.0%, respectively. With combined use of EBUS-TBNA and PET-CT, the sensitivity increased to 100%. Conclusion:The sensitivity, specificity, diagnostic accuracy, and negative predictive value and positive predictive value of EBUS-TBNA is higher than PET-CT. Based on conventional data, histological confirmation of PET-CT is necessary in mediastinal staging, due to high level of false positivity of PET-CT. EBUS-TBNA is an effective, reliable and minimally invasive method for histologic confirmation of PET-CT-positive malignant mediastinal/hilar lymph nodes.