Percutaneous Transthoracic Cutting Needle Biopsy of Pulmonary Lesions: Comparison of the Use of 18 and 20 Gauge Needles

PURPOSE: We evaluated the usefulness of a CT guided percutaneous transthoracic cutting needle biopsy (PCNB) using a 20 gauge (G) needle for pulmonary lesions after a comparison with the use of an 18 G needle for diagnostic accuracy and complications. MATERIALS AND METHODS: From August 2005 to July 2007, 433 patients underwent a CT guided PCNB. A total of 191 patients were excluded from the study as these patients had benign lesions seen after PCNB, but did not receive a confirmation biopsy or undergo follow-up (> 1 year). We evaluated the diagnostic accuracy for the use of PCNB using the Chi-squared test and analyzed which factors (location and size of lesions, diameter of the needle, distance between the pleura and lesions, presence or not of emphysema) were related to occurrence of a pneumothorax after PCNB using a multi-variant regression test. RESULTS: The diagnostic accuracy for malignant lesions with the use of an 18 G and a 20 G needle were 95.4% and 97%, respectively. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for the use of an 18 G needle were 95.7 %, 100%, 100%, and 91.6%. The sensitivity, specificity, PPV, and NPV were 97.8%, 100%, 100%, and 95.0% for the use of a 20 G needle. A pneumothorax occurred in 5.5% (24/433) of the cases and was closely related to the distance from the pleura to the lesions. CONCLUSION: CT guided PCNB with the use of a 20 gauge needle provided good diagnostic accuracy and the procedure is safe to perform.

Contrast-Enhanced MR Angiography of Failing Hemodialysis Arteriovenous Fistulas and Grafts: A Preliminary Experience

PURPOSE: The purpose of this report is to evaluate the vascular stenosis for failing hemodialysis arteriovenous fistulas and grafts using contrast-enhanced MR imaging (CE-MRI) and to compare the results with digital subtraction angiography (DSA). MATERIALS AND METHODS: Nine patients (27 segmental vessels) with symptoms and signs of AVF stenosis or occlusion who presented to our medical department were recruited into this prospective comparative study. All of the patients with Brescia-Cimino arteriovenous fistula (AVF) or synthetic polytetrafluoroethylene (PTFE, Goretex(R)) loop graft underwent MRA and DSA of the fistula. MRA was performed with a 1.5-T system using VIBE sequence: TR/TE=3.5/1.5 msec, flip angle 20-25degrees, matrix 115x256, FOV 350x350, interpolated slice thickness 2.0 mm, fat suppression, scan time 13-18 sec and total time of 5 min. DSA was used as the reference standard for assessing the accuracy of MRA, and MRA was analyzed for the presence of stenosis or occlusion, a grading of stenosis, and the presence of collateral vessels. Two radiologists prospectively analyzed the MRAs by working in consensus. RESULTS: Regarding the stenotic grade, CE-MRA corresponded with the DSA in six patients (66.7%) and it overestimated the stenoses in three patients (33.3%). For the stenotic site, MRA had a sensitivity of 86.4%, a specificity of 40%, a positive predictive value of 32.1%, and a negative predictive value of 66.7%. CONCLUSION:Multiphase CE-MRA of the AVF noninvasively provided information comparable to that provided by DSA for the vascular stenosis regarding failing hemodialysis arteriovenous fistula.