Lung-RADS Category 4X: Does It Improve Prediction of Malignancy in Subsolid Nodules?
Purpose To evaluate the added value of Lung CT Screening Reporting and Data System (Lung-RADS) assessment category 4X over categories 3, 4A, and 4B for differentiating between benign and malignant subsolid nodules (SSNs). Materials and Methods SSNs on all baseline computed tomographic (CT) scans from the National Lung Cancer Trial that would have been classified as Lung-RADS category 3 or higher were identified, resulting in 374 SSNs for analysis. An experienced screening radiologist volumetrically segmented all solid cores and located all malignant SSNs visible on baseline scans. Six experienced chest radiologists independently determined which nodules to upgrade to category 4X, a recently introduced category for lesions that demonstrate additional features or imaging findings that increase the suspicion of malignancy. Malignancy rates of purely size-based categories and category 4X were compared. Furthermore, the false-positive rates of category 4X lesions were calculated and observer variability was assessed by using Fleiss κ statistics. Results The observers upgraded 15%-24% of the SSNs to category 4X. The malignancy rate for 4X nodules varied from 46% to 57% per observer and was substantially higher than the malignancy rates of categories 3, 4A, and 4B SSNs without observer intervention (9%, 19%, and 23%, respectively). On average, the false-positive rate for category 4X nodules was 7% for category 3 SSNs, 7% for category 4A SSNs, and 19% for category 4B SSNs. Of the falsely upgraded benign lesions, on average 27% were transient. The agreement among the observers was moderate, with an average κ value of 0.535 (95% confidence interval: 0.509, 0.561). Conclusion The inclusion of a 4X assessment category for lesions suspicious for malignancy in a nodule management tool is of added value and results in high malignancy rates in the hands of experienced radiologists. Proof of the transient character of category 4X lesions at short-term follow-up could avoid unnecessary invasive management.©RSNA, 2017.
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Kaman
K
Chung
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Colin
C
Jacobs
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Ernst T
ET
Scholten
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Jin Mo
JM
Goo
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Helmut
H
Prosch
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Nicola
N
Sverzellati
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Francesco
F
Ciompi
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Onno M
OM
Mets
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Paul K
PK
Gerke
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Mathias
M
Prokop
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Bram
B
van Ginneken
From the Department of Radiology and Nuclear Medicine, Radboud University Nijmegen Medical Center, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands (K.C., C.J., E.T.S., F.C., P.K.G., M.P., B.v.G., C.M.S.P.); Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (J.M.G.); Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.M.G.); Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria (H.P.); Division of Radiology, Department of Clinical Sciences, University of Parma, Parma, Italy (N.S.); Department of Radiology, University Medical Center Utrecht, the Netherlands (O.M.M.); and Department of Radiology, Meander Medical Center, Amersfoort, the Netherlands (C.M.S.P.).
Cornelia M
CM
Schaefer-Prokop
D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging* / Q000473:pathology*; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed / Q000379:methods