Magnetic Resonance Imaging-guided Percutaneous Coaxial Biopsy Of Small Pulmonary Nodules(≤2.0cm)

Part I:0.23T open MR Imaging-guided percutaneous coaxial biopsy of small pulmonary nodules (≤2cm):sequence selectionObjective:To evaluate the ability of0.23T low field interventional magnetic resonance imaging system frequently applied several sequences (FSE T1WI, FSE T2WI, FE T1WI, FSE T1WI enhanced, FE T1WI enhanced, CBASS) in displaying small pulmonary nodules (≤2.0cm).Materials and Methods:44small pulmonary nodules (≤2.0cm) in36patients were divided into three groups according to the nodule displaying in chest CT:solid nodules (n=28), ground glass nodules (n=9) and mixed nodules (n=7). We scan the44small pulmonary nodules by using of0.23T low field interventional magnetic resonance imaging system frequently applied several sequences (FSE Tl WI, FSE T2WI, FE T1WI, FSE T1WI enhanced, FE T1WI enhanced, CBASS), observe whether the nodule could be displayed, and measure the nodule diameters in the above sequences. Comparison of the nodule diameters in magnetic resonance sequences transaxial scans with the nodule diameters in CT pulmonary window, to determine whether the sequence can clearly and accurately show the pulmonary nodules. Additionally, we record the sequence scanning time, whether the nodule display could be interfered by the cardiovascular pulsation artifact and magnetic field inhomogeneity, to obtain a comprehensive judgment whether the sequence is suitable for application in magnetic resonance guided percutaneous puncture biopsy of small pulmonary nodules. Results:Solid nodules:FSE T1WI, FSE T2WI, FE T1WI, FSE T1WI+enhanced and FE T1WI+enhanced sequence can clearly display the nodules, there was no significant difference between the diameter of the nodules on MRI and the CT lung window. CBASS sequence can display solid nodules, but the diameter of the nodules on MRI was significantly less than on CT lung window.Ground glass nodules and mixed nodules:FSE T1WI+enhanced and FE T1WI+enhanced sequence scan could clearly display the nodules and accurately display the nodule size. Some ground glass nodules can not be clearly displayed in FSE T1WI, FE T1WI, FSE T2WI and CBASS sequence, and the nodule diameter on above sequence was smaller than that on CT lung window.Scan time:sequence scanning time within20seconds:FSE T1WI5slices (20s) and FE T1WI5slices (18s), suitable for application in patients who need hold breath; more than20seconds:FSE T2WI7slices (26s) and CBASS9slices (28s) is not suitable for application in patients who need hold breath.The heart and aortic pulsation artifact interference:the heart and aortic pulsation artifact interference in FSE T1WI, FSE T2WI, CBASS series axial scanning and FE T1WI sequence of coronal and sagittal scanning is light; the heart and aortic pulsation artifact interference in FE T1WI sequence axial scanning is serious.The inhomogeneous magnetic field interference:CBASS sequence is susceptible to be interfered by the inhomogeneous magnetic field, but the rest sequences have no problems.Conclusions:FSE T1WI enhanced sequence is most suitable for locating the position of small pulmonary nodules, and FE T1WI enhanced sequence is most suitable for monitoring the needle direction and position in the puncture procedure. Part Ⅱ:MRI-guided Percutaneous Coaxial Cutting Needle Biopsy of Small Pulmonary Nodules:FeasibilityObjectives:To prospectively evaluate the feasibility, safety and accuracy of magnetic resonance imaging (MRI)-guided percutaneous coaxial cutting needle biopsy of small (≤2.0cm in diameter) pulmonary nodules.Methods:Ninety-six patients (56men and40women) with96small lung nodules underwent MRI-guided percutaneous coaxial cutting needle biopsy. These lesions were divided into two groups according to maximum nodule diameters:0.5-1.0cm (n=25) and1.1-2.0cm in (n=71). The diagnostic accuracy, sensitivity, and specificity were calculated respectively, and comparison of the two groups was performed by use of Fisher’s exact test.Results:All specimens obtained were sufficient for diagnosis. Histological examination of needle biopsy revealed64malignant,30benign and2indeterminate nodules. The final clinical diagnoses from surgery or clinical follow-up were67malignant nodules and29benign nodules. The diagnostic performance of MRI-guided percutaneous coaxial cutting needle biopsy in diagnosing malignant tumours was as follows:accuracy,97%; sensitivity,96%; specificity,100%; positive predictive value,100%; and negative predictive value,91%. The accuracy, sensitivity and specificity were96%,94%and100%for the lesions1cm or smaller and97%,96%and100%for the lesions larger than1cm. There was no significant difference between the two groups (P>0.05, Fisher’s exact test). No serious complications occurred.Conclusions:MRI-guided percutaneous coaxial cutting needle biopsy is a safe and accurate diagnostic technique in the evaluation of small lung nodules.