Med Bull Sisli Etfal Hosp. 2021; 55(1): 12-17 | DOI: 10.14744/SEMB.2020.80270

Comparison of MRI and 18F-FDG PET/CT in the Liver Metastases of Gastrointestinal and Pancreaticobiliary Tumors

Mehmet Tahtabasi¹, Sukru Mehmet Erturk², Muzaffer Basak^3
1Department of Radiology, University of Health Sciences Turkey, Mehmet Akif Inan Training and Research Hospital, Sanliurfa, Turkey
²Department of Radiology, Istanbul University Faculty of Medicine, Istanbul, Turkey
³Department of Radiology, University of Health Sciences Turkey, Sisli Hamidiye Etfal Teaching and Research Hospital, Istanbul, Turkey

Objectives: To compare the efficacy of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT) and magnetic resonance imaging (MRI) in the detection of liver metastases originating from the gastrointestinal system (GIS) and the pancreaticobiliary (PB) system.
Methods: This retrospective study included 42 patients with primary GIS (stomach or colorectal) or PB system malignancies that metastasized to the liver, histopathologically confirmed diagnoses, and MRI and 18F-FDG PET/CT images. The MRI and 18F-FDG PET/CT images were analyzed. Student's t-test was used to compare the two modalities in terms of determining the number of metastases, and Cohen's kappa test was conducted to determine the agreement between the modalities.
Results: Twenty-eight (66.7%) of the patients included in this study were male, and the mean age was 60.67±9.4 years. Colon (n=25; 59.5%) and pancreatic (n=7; 16.6%) adenocarcinomas were the most common primary tumors that had metastasized to the liver. MRI detected more metastases in 12 (28.5%) patients, less in seven (16.6%), and an equal number of metastases in 23 (54.7%). No statistically significant difference was observed between the number of metastases detected by MRI and 18F-FDG PET/CT (7.55±7.96 and 6.36±7.28, respectively; p=0.11). There was a moderate agreement between the two modalities (kappa value=0.423). Most of the metastases detected on MRI but not seen on 18F-FDG PET/CT (n=10, 23.8%) were lesions smaller than 10 mm. For the eight (19%) patients with lymph node metastases, the number of metastatic lymph nodes detected by MRI and 18F-FDG PET/CT was similar (12 and 14, respectively, p>0.05).
Conclusion: MRI can detect small lesions at an early stage, and 18F-FDG PET/CT shows the metabolic activity of lesions; therefore, the combined use of the two modalities can potentially offer a beneficial outcome for patients.

Keywords: Liver metastasis, gastrointestinal tumor, pancreatic tumor; magnetic resonance imaging; positron emission tomography.

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Gastrointestinal ve Pankreatiko-Bilyer Tümörlerin Karaciðer Metastazlarýnda MRG ve 18F-FDG PET/CT'nin Karþýlaþtýrýlmasý

Mehmet Tahtabasi¹, Sukru Mehmet Erturk², Muzaffer Basak^3
1Saðlýk Bilimleri Üniversitesi, Mehmet Akif Ýnan Eðitim ve Araþtýrma Hastanesi, Radyoloji Bölümü, Þanlýurfa
²Ýstanbul Üniversitesi Ýstanbul Týp Fakültesi, Radyoloji Anabilim Dalý, Ýstanbul
³Saðlýk Bilimleri Üniversitesi, Þiþli Hamidiye Etfal Eðitim ve Araþtýrma Hastanesi, Radyoloji Bölümü, Ýstanbul

Amaç: Gastrointestinal sistem (GÝS) ve pankreatiko-bilyer (PB) sistem kaynaklý karaciðer metastazlarýnýn tespitinde 18F-fluorodeoxyglucose pozitron emisyon tomografi (18F-FDG PET/BT) ve manyetik rezonans görüntüleme (MRG)’nin etkinliðinin karþýlaþtýrýlmasýdýr.
Gereç ve Yöntemler: Bu retrospektif çalýþmaya primer GÝS (mide veya kolorektal) veya PB sistem malignitesi olup karaciðere metastaz yapmýþ, histopatolojik olarak tanýsý doðrulanmýþ, MRG ve 18F-FDG PET/BT’si bulunan 42 hasta dahil edildi. MRG ve 18F-FDG PET/BT görüntüleri prospektif olarak analiz edildi. Metastaz sayýlarýnýn tespitinde iki modaliteyi karþýlaþtýrmak için Student's t-testi ve modaliteler arasý uyumu belirlemek için Cohen’s kappa testi kullanýldý.
Bulgular: Çalýþmaya dahil edilen hastalarýn 28 (%66.7)’i erkek olup, yaþ ortalamasý 60.67±9.4 yýl idi. Kolon (n=25; %59.5) ve pankreas (n=7; %16.6) adenokarsinomu metastaz yapan en sýk primer tümörlerdi. MRG ile 12 (%28.5) hastada daha fazla sayýda, 7 (%16.6) hastada daha az sayýda ve 23 (%54.7) hastada ise eþit sayýda metastaz tespit edildi. MRG ve 18F-FDG PET/BT ile tespit edilen metastaz sayýsý arasýnda istatistiksel olarak anlamlý fark yoktu (sýrasýyla; 7.55 ± 7.96 ve 6.36 ± 7.28; p = 0.11). Ýki modalite arasýnda orta derece uyum mevcuttu (kappa deðeri = 0.423). MRG’de tespit edilip 18F-FDG PET/BT’de görülmeyen metastazlarýn büyük kýsmý (n=10, %23,8) 10 mm’den küçük lezyonlardý. Lenf nodu metastazý olan 8 (%19) hastada MRG ve 18F-FDG PET/BT’nin lenf nodu saptama sayýlarý benzerdi (sýrasýyla, 12’ye 14 adet, p> 0.05).
Sonuç: MRG’nin lezyonlarý küçük boyutlarda erken aþamada tespit etmesi ve 18F-FDG PET/BT’nin lezyonlarýn metabolik aktivitesini göstermesi nedeniyle her iki modalitenin kombine kullanýlmasý hastalara daha fazla fayda saðlayacaktýr. (SETB-2020-11-234)

Anahtar Kelimeler: Karaciðer metastazý, Gastrointestinal tümör, Pankreas tümörü, Manyetik rezonans görüntüleme, Pozitron emisyon tomografisi

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