With recent advances in target

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C a r d i o p u l m o n a r y I m a g i n g • P i c t o r i a l E s s ay Tsai et al. CT-Guided Lung Biopsy

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Cardiopulmonary Imaging Pictorial Essay

I-Chen Tsai1,2 Wei-Lin Tsai1,2 Min-Chi Chen1,3 Gee-Chen Chang 4,5,6 Wen-Sheng Tzeng 3,7,8 Si-Wa Chan1 Clayton Chi-Chang Chen1,3,9,10 Keywords: biopsy, CT, lung, lung Tsai IC, Tsai WL, Chen MC, etcancer al. DOI:10.2214/AJR.08.2113 Received November 15, 2008; accepted after revision April 17, 2009. 1 Department of Radiology, Taichung Veterans General Hospital, Taichung, Taiwan. 2

Institute of Clinical Medicine, National Yang Ming University, Taichung, Taiwan.

3 Department of Radiological Technology and Graduate Institute of Radiological Science, Central Taiwan University of Science and Technology, Taichung, Taiwan. 4 Division of Chest Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan. 5 School of Medicine, China Medical University, Taichung, Taiwan. 6

Institute of Biomedical Sciences, National Chung-Hsing University, Taichung, Taiwan. 7 Department of Medical Imaging, Chi-Mei Foundation Medical Center, No. 901, Chung Hwa Rd., Yong Kang City, Tainan 710, Taiwan. Address correspondence to W. S. Tzeng. 8 Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. 9 Department of Physical Therapy, Hungkuang University of Technology, Taichung, Taiwan. 10 Department of Physical Therapy and Assistive Technology, National Yang Ming University, Taipei, Taiwan.

CME This article is available for CME credit. See www.arrs.org for more information. AJR 2009; 193:1228–1235 0361–803X/09/1935–1228 © American Roentgen Ray Society

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CT-Guided Core Biopsy of Lung Lesions: A Primer OBJECTIVE. CT-guided core biopsy is playing an increasing role in the diagnosis of benign disease, cellular differentiation, somatic mutation analysis, and molecular fingerprint analysis. CONCLUSION. In this article, we summarize the basic concepts, protocols, and techniques that we use for CT-guided core biopsy of lung lesions to assist radiologists in obtaining diagnostic specimens while reducing preventable complications.

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ith recent advances in target therapy [1], obtaining tumor tissue to analyze for the molecular fingerprint of somatic mutation for personalized medicine will be a major trend in the future [1]. In addition to its traditional diagnostic role, CT-guided lung biopsy also plays a key role in personalized treatment [2]. Compared with aspiration cytology, coaxial core biopsy is preferred because it can obtain multiple large specimens for diagnosis [3] and molecular analysis [2]. Thus, in the near future, CT-guided coaxial core biopsy will be an important technique in the personalized treatment of lung cancer. Many radiologists around the world are well trained for fine-needle aspiration of lung lesions. However, a coaxial needle requires careful manipulation to avoid an air embolism. Core biopsy requires special attention to avoid cutting the vessel surrounding the tumor in order to prevent major hemorrhage. Many experienced medical centers report the low complication rate and safety of CT-guided biopsy. At our institute, the complication rates are 27.9% for pneumothorax (21.3% resolved spontaneously, 6.6% requiring tube drainage), 14.8% for hemoptysis, 0.3% for severe hemothorax requiring endotracheal intubation, and 0% for procedure-related mortality, which is similar to previous reports [2–4]. Overall, national surveys [5, 6] continue to show major complications and death. This means many radiologists may benefit from a guide to help improve their technique and to reduce procedure-related complications. In this article, we share our key concepts and techniques regarding CTguided core biopsies of lung lesions.

Basic Concepts Respiratory Motion The lower lung zones (below the hili) are more affected by respiratory motion than the upper (Figs. 1–3). Contrary to conventional practice, we allow the patient to breathe freely and quietly during the biopsy procedure (Fig. 3). There are two reasons for not making them hold their breath: Reproducibility of diaphragm position between breath-holds is not good, and after a breath-hold, the following deep respiration may cause needle laceration to the pleura. We directly observe the patient’s breath rhythm and insert the needle during inspiration. Cardiac Motion The left lingula, near the left ventricle and pulmonary trunk, is most affected by cardiac motion (Fig. 4). While performing biopsy in the lingula, take care to avoid myocardium or epicardial coronary artery injury. Chest Wall Vessels Generally, avoid all vessels greater than 5 mm seen on chest CT. When biopsying an anterior lesion behind vessels in the upper chest, such as the subclavian or internal thoracic vessels, a path should be chosen that avoids the vessels (Fig. 5). Also, to avoid intercostal arteries, insert the coaxial needle above rather than below the rib. Preprocedural Laboratory Check Coagulation factors, such as platelet count, prothrombin time, and activated partial thromboplastin time, should be checked before the procedure. Any anticoagulants or platelet inhibitors such as aspirin should be

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withheld. Use the British Thoracic Society guideline as a general reference for proper biopsy procedures [7]. Fissures In our experience, traversing the fissure with a 17-gauge coaxial needle results in a high probability of pneumothorax. Informed consent should be obtained for all biopsies, but if there is likelihood of traversing a fissure, the patient should be informed of the increased risk of a pneumothorax as a complication. Shock Wave Injury During Biopsy When the biopsy gun fires, the shock wave distal to the biopsy needle tip is strong. The areas lateral to the needle will be also affected by the vibration. Shock wave injury to lung parenchyma is usually evidenced by mild hemorrhage (Figs. 1 and 6). Thus, these regions, distal to the tip and lateral to the needle, should be considered danger zones. Major vessels should be well away from these danger zones. Informed Consent Because CT-guided lung biopsy is an invasive procedure with potential complications, including death [5, 6], obtaining informed consent with the patient and his or her family understanding the procedure and potential risks is important. The British Thoracic Society [7] guideline further suggests, “Operators should audit their own practice and calculate their complication rates to inform patients before consent is given.” Scan Protocols During the procedure, we obtain a routine low-dose axial scan with 120 kVp, 30 mAs per slice, 0.75-second rotation time, and collimation of 8 × 5 mm on a 64-MDCT scanner (Brilliance 64, Philips Healthcare). For scanners of other vendors, the suggested axial scanning parameters are 120 kVp, 30 mAs per slice, 0.5- to 1-second rotation time, and collimation of 5 mm. The window center and width are 0 and 2,800 HU, respectively, which allows simultaneous visualization of vessels, tumor, pneumothorax, bone, muscle, and fat. The procedure is performed with a “move off and scan” approach [2–4, 8–10] (Fig. 7) to minimize radiation exposure to the operator as compared with CT fluoroscopy [11]. If multiplanar reformation or volume-rendering images are needed for detailed needle localization, we obtain a low-dose thin-collimation spiral scan (120 kV, 40 mAs per slice, rotation time of 0.75

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second, pitch of 0.924, collimation of 64 × 0.625 mm) (Figs. 3 and 8). “The patient as partner” approach cannot be overemphasized [8]. We routinely inform the patient that the procedure takes only about 30 minutes and that his or her cooperation is the key to success [8]. Techniques Coaxial Technique The coaxial technique to obtain a core biopsy is suggested for the following reasons: It yields good stabilization in the chest wall because of the lightness of the coaxial needle; and it allows multiple sampling, improving diagnostic yield [12]. When performing the coaxial technique, never leave the outer cannula inside the patient without the inner stylet (Fig. 9). To do so in a small branch of a pulmonary vein could result in a devastating air embolism, leading to myocardial infarction, stroke, or even death [13]. At our institute, we use a 17-gauge coaxial needle (TruGuide, Bard) with a length of 13 cm for most cases. Sometimes, a 17-gauge coaxial needle with a length of 17 cm is used for deep lesions. The core biopsy is routinely performed with the matching 18-gauge cutting needle (Magnum Needles, Bard) and biopsy gun (Magnum, Bard). Local Anesthesia The distance between the skin and pleura should be measured. The needle tip should never advance through pleura (Fig. 2) when injecting local anesthesia (Xylocaine 2% [lidocaine], AstraZeneca). Otherwise, pneumothorax might develop, making the following procedure more difficult. Sterile Drape as Needle Holder If the distance between skin and pleura is short, the fixing force from the chest wall to stabilize the coaxial needle may be weak (Fig. 2). In such circumstances, we shape a sterile drape into a needle holder during scanning. The needle can then be fixed in the planned direction to provide more information during the following scan (Fig. 2). If the needle is aimed at the lesion on the following scan, you may insert the needle farther according to the direction indicated by your handmade needle holder. Dynamic Needle Manipulation When inserting the coaxial needle, a rapid thrust to the subpleural region for at least 1 cm should be done (Figs. 1 and 10) to avoid nee-

dle tip laceration to the pleura and to avoid the outer cannula slipping into the pleural space during breathing. It is a dynamic process (Fig. 1) from skin to the lesion; always use the latest scan for planning, and do not strictly adhere to the initial planning and angle. During the whole procedure, the patient moves, lung parenchyma moves, and pneumothorax might develop. Thus, only some procedures exactly follow your initial planning; most cases require adaptation and modification during the procedure (Fig. 1). Final Manipulation Final manipulation is an important technique for increasing diagnostic yield and avoiding complications. If the coaxial needle is inserted to the periphery of the tumor rather than the center, we still can get diagnostic tissue by aligning the coaxial needle to the lesion before biopsy. Direct inspection can confirm if the specimen is adequate (Fig. 6). Also, postbiopsy scanning can help in localizing the biopsy direction by visualizing the small hemorrhage caused by the shock wave of the biopsy gun (Fig. 6). The final manipulation technique is particularly useful in conducting small nodule core biopsy (Fig. 6) on lesions located near the diaphragm (Fig. 3) and avoiding vessel injury (Fig. 11). Biopsy Under Pneumothorax CT-guided biopsy of lung lesions can be done under stable pneumothorax, if the lesion is close to the pleural surface [10]. The pneumothorax may be caused by previous sonographically guided biopsy or by the first coaxial needle entry. When pneumothorax occurs, scan the same position 3 minutes later to see if the pneumothorax is progressing. If progressing, we suggest insertion of a pigtail catheter and stopping the procedure. If the pneumothorax is stable, with the final manipulation technique, diagnostic specimens can be obtained [10] (Fig. 12). Biopsy Groove Length Selection In our system, two biopsy sample lengths can be selected, 22 and 15 mm. The general principle is to use the long groove for obtaining more tissue (Fig. 6). The short biopsy groove is only used for avoiding injury to the vessels behind the tumor. Review Your Cases After the procedure, review to see how closely the procedure followed your plan (Figs. 1–3, 6, 8, 11, 12), to see if the specimen

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obtained was adequate for the pathologist, and to determine whether the patient developed complications. Conclusion Because CT-guided core biopsy is playing an increasing role in benign disease diagnosis, cellular differentiation, somatic mutation analysis, and molecular fingerprint analysis, radiologists should be familiar with the associated techniques so that they may safely obtain diagnostic specimens while minimizing complications. Acknowledgments We thank Chih-Ming Chiang, Yung-Chieh Chang, and Wan-Chun Liao for preparation of the figures. References 1. Paez JG, Jänne PA, Lee JC, et al. EGFR mutations in lung cancer: correlation with clinical response to gefitinib therapy. Science 2004; 304:1497–1500

Fig. 1—57-year-old woman with 1.5-cm groundglass opacity lesion over right lung apex who underwent CT-guided biopsy. Pathology revealed adenocarcinoma. Case shows that biopsy procedure is dynamic process. A, Axial low-dose CT scan over right lung apex. After injection of local anesthesia, leave hypodermic needle (arrow) as you planned to see whether needle is really aimed at lesion (T). In this image, needle is aimed at left periphery, not center, of tumor. B, After several courses of needle advancement and manipulation, coaxial needle (arrow) is placed at periphery of tumor (T) and biopsy track traverses tumor center. Exchange inner stylet for biopsy needle, which is attached to biopsy gun. After biopsy, because of shock wave produced by biopsy gun, mild hemorrhage is seen in distal portion of needle tip (white arrowheads) and lateral to biopsy needle (black arrowheads). See Figure S1 in supplemental data at www.ajronline.org to view dynamic process, from injecting local anesthesia to final biopsy.

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2. Chen CM, Chang JW, Cheung YC, et al. Computed tomography-guided core-needle biopsy specimens show epidermal growth factor receptor mutations in patients with non-small-cell lung cancer. Acta Radiol 2008; 49:991–994 3. Anderson JM, Murchison J, Patel D. CT-guided lung biopsy: factors influencing diagnostic yield and complication rate. Clin Radiol 2003; 58:791–797 4. Charig MJ, Phillips AJ. CT-guided cutting needle biopsy of lung lesions: safety and efficacy of an outpatient service. Clin Radiol 2000; 55:964–969 5. Richardson CM, Pointon KS, Manhire AR, Macfarlane JT. Percutaneous lung biopsies: a survey of UK practice based on 5444 biopsies. Br J Radiol 2002; 75:731–735 6. Tomiyama N, Yasuhara Y, Nakajima Y, et al. CTguided needle biopsy of lung lesions: a survey of severe complication based on 9783 biopsies in Japan. Eur J Radiol 2006; 59:60–64 7. Manhire A, Charig M, Clelland C, et al. Guidelines for radiologically guided lung biopsy. Thorax 2003; 58:920–936

8. Moore EH. Technical aspects of needle aspiration lung biopsy: a personal perspective. Radiology 1998; 208:303–318 9. Gupta S, Seaberg K, Wallace MJ, et al. Imagingguided percutaneous biopsy of mediastinal lesions: different approaches and anatomic considerations. RadioGraphics 2005; 25:763–786 10. Chang YC, Wang HC, Yang PC. Usefulness of computed tomography-guided transthoracic smallbore coaxial core biopsy in the presence of a pneumothorax. J Thorac Imaging 2003; 18:21–26 11. Stoeckelhuber BM, Leibecke T, Schulz E, et al. Radiation dose to the radiologist’s hand during continuous CT fluoroscopy-guided interventions. Cardiovasc Intervent Radiol 2005; 28:589–594 12. Lucidarme O, Howarth N, Finet JF, Grenier PA. Intrapulmonary lesions: percutaneous automated biopsy with a detachable, 18-gauge, coaxial cutting needle. Radiology 1998; 207:759–765 13. Ghafoori M, Varedi P. Systemic air embolism after percutaneous transthoracic needle biopsy of the lung. Emerg Radiol 2008; 15:353–356

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Fig. 2—82-year-old man with lymphoma after treatment, now with growing tumor over right upper lobe of lung, who was referred for CT-guided lung biopsy. Pathology revealed tuberculosis. This case shows sterile-drape-as-needle-holder technique for trajectory alignment. A, Initial CT scan and trajectory planning. In initial localization scan, plan trajectory from right lateral chest wall to tumor (T) with 55° angle from vertical line (white double arrow). Then skin-to-pleura (black double arrow) and skin-to-lesion distances are measured. Skin-to-pleura distance is only 22 mm. Because hypodermic needle for local anesthesia is 32 mm long, needle cannot be totally inserted, or puncture to pleura may cause pneumothorax. B, CT scan after administration of local anesthesia. Because of thin chest wall, needle (arrow) angle (61°) differs from that initially planned (55°). Distal extended line, as shown by beam-hardening artifact (white arrowheads), is not aimed at tumor (T). Plan was to pass coaxial needle between two visualized small vessels (black arrowheads) and biopsy tumor. C, Photograph during biopsy after coaxial needle insertion with hand support. With assistance of technologist, operator inserted coaxial needle (arrow) into chest wall at 55° angle. Sterile drape (D) was prepared for later use. D, Photograph during biopsy after coaxial needle insertion without hand support. Because chest wall is thin, fixation force is insufficient. Needle toppled (arrow), making angle much larger than 55°. This is not angle we want, and scan will not provide information for further needle adjustment. Sterile drape (D) was prepared for later use. E, Photograph during coaxial needle insertion with sterile drape as needle holder. Sterile drape (D) is shaped to support needle (arrow). With assistance of technologist, needle is now at 55°, angle we want. At this time, operator can leave scanning room and obtain another axial scan to confirm trajectory. F, Next CT scan with coaxial needle (arrow) supported by sterile drape (D). Needle angle now is exactly 55°. Beam-hardening artifact (white arrowheads), which serves as extension of needle, is also aimed at tumor. Two vessels (black arrowheads) near tumor (T) should be avoided during further needle insertion. G, Axial low-dose CT scan with coaxial needle on periphery of tumor. After two attempts, coaxial needle (arrow) is now on periphery of tumor (T) without having injured any visible vessel (black arrowheads). With beam-hardening artifact (white arrowheads), biopsy track is confirmed to traverse tumor. Biopsy is then successfully completed without complication. Note that 4° of inaccuracy would injure major pulmonary vessel branch.

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Fig. 3—76-year-old man with underlying hepatocellular carcinoma. New nodule in right lower lobe of lung was noted in routine follow-up abdominal CT scan. CT-guided biopsy revealed organizing pneumonia. Case shows techniques of near-diaphragm lesion biopsy and z-axis final manipulation. A, Localization prone CT scan. This image shows two potential approaches (white and black arrows) to lesion (T). Posterolateral approach (white arrow) is feasible, but sharp angle between needle path and pleura could potentially result in pneumothorax. Distal shock wave of posterolateral approach might injure paravertebral vessels such as intercostal arteries. Thus, we decided to use posterior approach (black arrow). Rib is blocking posterior approach, so we decided to use z-axis manipulation to approach tumor. B, CT scan after coaxial needle approached lesion (T). Scan level is slightly caudad to that in A. We inserted needle in periphery of tumor (T), and we planned to do final manipulation in z-axis to approach tumor. Biopsy could not be performed without manipulation (arrowheads) because diaphragm would be injured. C, Sagittal reformation of needle and lesion (T) after biopsy. Coaxial needle is now inserted in tumor periphery, where, with z-axis final manipulation (curved arrow), needle can aim at center of tumor (T). With postbiopsy hemorrhage posterior to tumor, biopsy direction is confirmed. Actual biopsy track (black arrowheads) is different from original needle direction (white arrowheads). In this case, diaphragm was successfully avoided and tumor biopsied without complication.

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Fig. 4—72-year-old man undergoing ECG-gated cardiac CT. Images and cine figures are reconstructed in lung window with large field of view to show effect of cardiac motion on lung parenchyma and implications for CT-guided biopsy. A, Axial nongated image at aortic root. If cardiac CT raw data are reconstructed without ECG signal, reconstructed still image is same as routine chest CT scan. In lungs, regions near left ventricle (black arrowheads), right ventricular outflow tract (RVOT), and pulmonary trunk are affected by cardiac motion, as shown by motion artifact (white and black arrowheads). Left lingula (black arrowheads) is affected most, followed by right middle lobe (white arrowhead). Note that perihilar areas and regions near descending aorta (DAO) are not affected. See Figure S4A in supplemental data at www.ajronline.org to view lung movement during heart cycle at this level. LAA = left atrial appendage, AAO = ascending aorta. B, Axial nongated image at level of left ventricular outflow tract. Left lingula (black arrowheads) is affected by left ventricular (LV) motion. At this level, right middle lobe (white arrowhead) is not obviously affected by right ventricular (RV) motion. See Figure S4B in supplemental data at www.ajronline.org to view lung movement during heart cycle. DAO = descending aorta, LA = left atrium, RA = right atrium.

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Fig. 5—Chest wall vessels related to CT-guided biopsy. Images from different patients show anatomic details. A, Axial chest CT scan at level of subclavian vessels in 68-year-old man. Tumor (T) over left lung apex is noted. Anterolateral approach (dashed arrow) would injure subclavian vessels (arrowheads). Thus, posterior approach (solid arrow) is better. Even though image here shows rib blocking posterior approach, with patient in prone position, relationship between lesion and rib may change. Otherwise, z-axis manipulation can be used to approach lesion, as shown in Figure 3. B, Axial low-dose scan during CT-guided biopsy in 56-year-old woman. Even with low-dose CT scan during biopsy, internal thoracic vessels (white arrowheads) and lateral thoracic vessels (black arrowheads) can be well visualized; these are vessels to be avoided. Injuring internal thoracic artery in patient after coronary artery bypass surgery may cause myocardial infarction. C, Volume-rendering technique of intercostal arteries (arrows and arrowheads), ribs, and scapula (S) in 56-year-old woman. Intercostal arteries above lower margin of scapula are small and almost invisible (arrows). However, intercostal arteries below scapula are larger (white and black arrowheads). In lateral and posterolateral wall (white arrowheads), intercostal arteries are located at inferior margin of ribs. However, at posteromedial wall, course is unpredictable. Intercostal arteries could be in center of intercostal space or even at superior margin of rib (black arrowheads). Thus, when doing CT-guided biopsy for apical lung lesion with posterior approach, intercostal arteries are not of concern. If lateral or posterolateral approach is used, avoid inserting needle from inferior margin of ribs. On axial low-dose CT scan, intercostal arteries are not visible because of volume averaging.

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Fig. 6—65-year-old woman with 7-mm ground-glass nodule over right lower lung. Case shows importance of final manipulation in small-nodule core biopsy. Pathology revealed adenocarcinoma. A, Axial image with coaxial needle inserted. Even after meticulous manipulations, coaxial needle is not aiming at small nodule. Thus, we use final manipulation technique (arrow) to align coaxial needle to small nodule (arrowheads) before performing biopsy. In small-nodule biopsy, remember to use long biopsy groove (in this case, 22 mm) to totally traverse small nodule so as to obtain large diagnostic specimen. B, Axial CT scan after biopsy. Notice shock wave hemorrhage (white arrowheads) traversing small nodule (black arrowheads), confirming correct direction of final manipulation. C, Photograph of biopsy groove shows 7-mm nodule (arrowheads) is successfully sampled. Pathology revealed adenocarcinoma.

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Tsai et al.

A Fig. 7—Photograph of scene of CT-guided biopsy. We use IV stand, bracket (B), and plank, available from any hardware store, to make portable platform to position protractor (P) close to coaxial needle to avoid visualization bias. Protractor should be calibrated by spirit level (SL) with paper or tongue depressors. Also, we designed rear sight (such as one on rifle) to aim at coaxial needle for precision. In technologist’s (T) eye, coaxial needle will appear in long slit of rear sight, making it easy to confirm angle. Isolation gown on radiologist (R) is not sterile; thus, sleeve is rolled up to avoid contaminating sterile gloves and sterile area.

Fig. 9—Stylet exchange technique to avoid air embolism. A, Photograph during stylet exchange. After coaxial needle is inserted into tumor periphery, we exchange inner stylet for biopsy needle. During exchange, left hand (LH) should fix outer needle (white arrowhead) position on patient to prevent further insertion. Little finger (arrow) rests on patient and remaining fingers are used to fix outer cannula, while right hand (RH) is screwing inner stylet (black arrowhead). B, Photograph during stylet exchange. When inner stylet is removed, thumb (black arrowhead) should be used to cover proximal hole of outer needle before biopsy needle, attached to biopsy gun (G), enters. Little finger (arrow) still rests on patient and remaining fingers fix outer cannula (white arrowhead). This is important technique to prevent air embolism, which can result in myocardial infarction, stroke, or death.

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Fig. 8—62-year-old man with left upper lobe nodule near hilum. CT-guided biopsy revealed adenocarcinoma. With proper planning and good technique, even hilar lesions can be biopsied successfully without complication. A, Axial low-dose CT scan after coaxial needle is inserted into tumor periphery. With precise planning and meticulous manipulation, all visible vessels are avoided. Closest vessel is only 5 mm away from needle. Although tree-in-bud pattern (black arrowheads) is noted in adjacent region, tumor (white arrowhead) proves to be adenocarcinoma. Surgical pathology revealed tree-in-bud pattern to be tuberculosis. This is case of mixed tuberculosis and adenocarcinoma. B, Slab volume-rendering image of CT scan. Tumor (arrowhead) is surrounded by many hilar vessels. If we can find trajectory avoiding all visible vessels, biopsy can still be done without complication.

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CT-Guided Lung Biopsy

Fig. 10—Distance between tips of outer cannula and inner stylet is shown in photograph of tip of coaxial needle. Most coaxial needles, like one seen here, have 5-mm gap between inner needle tip (black arrowhead) and outer cannula tip (white arrowhead). When performing subpleural lesion biopsy, never let outer needle tip slip into pleural space because that will result in pneumothorax. Also notice that scale on needle counts from tip of outer needle (white arrowhead), which means that first tick (arrow) is 1.5 cm, rather than 1.0 cm, from inner needle tip.

Fig. 11—38-year-old woman with right lower lobe mass who underwent CT-guided biopsy. Pathology revealed adenocarcinoma. Case shows importance of final manipulation to avoid vessel injury. Axial low-dose CT scan during procedure shows needle is inserted into periphery of tumor (T). Bronchus (white arrowhead) and vessel (black arrowhead) behind tumor should be avoided during biopsy. If biopsy is done without any manipulation, vessel (black arrowhead) behind tumor will be injured because beam-hardening artifact (straight arrows) is traversing vessel wall. Thus, before biopsy, we manipulate coaxial needle (curved arrow) to aim at medial portion of tumor. Specimen was then successfully obtained without complication such as pulmonary hemorrhage.

Fig. 12—56-year-old man with right lower lobe subpleural nodule needing CT-guided biopsy. Case shows that biopsy can still be done under stable pneumothorax. After coaxial needle was inserted through pleura, pneumothorax (asterisk) developed immediately. Although location of needle tip is as planned, nodule (T) is going distally with partially collapsed lung. With final manipulation, coaxial needle is angled (curved arrow) and inserted deeper (straight arrow) before biopsy gun is fired. Specimen was successfully obtained. Culture revealed nontuberculous Mycobacterium organism. H = hematoma caused by injection of local anesthetic.

F O R YO U R I N F O R M AT I O N

• This article is available for CME credit. See www.arrs.org for more information. • The data supplement accompanying this article can be viewed from the information box in the upper right corner of the article at: www.ajronline.org.

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