Core Needle Biopsy of the Thyroid: 2016 Consensus Statement and Recommendations from Korean Society of Thyroid Radiology
Korean J Radiol. 2017 Jan-Feb; 18(1): 217–237.
1. Core needle biopsy (CNB) has been suggested as a complementary diagnostic method to fine-needle aspiration in patients with thyroid nodules.
2.Many recent CNB studies have suggested a more advanced role for CNB, but there are still no guidelines on its use.
3.Therefore, the Task Force Committee of the Korean Society of Thyroid Radiology has developed the present consensus statement and recommendations for the role of CNB in the diagnosis of thyroid nodules.
4. Summary on CNB for thyroid nodules.
|Indication||1. CNB could be alternative to FNA in evaluation of thyroid nodules in selected cases|
|Device and procedure||2. Modern CNB devices, particularly 18–21-gauge, spring-activated, core needles, are recommended for procedure|
|3. Patients with bleeding tendency, such as those taking anticoagulation medications or with disorders affecting coagulation cascade, should be thoroughly evaluated and any problems corrected before CNB|
|4A. CNB should be performed by experienced operators under US guidance|
|4B. Manual compression of biopsy site should be performed immediately after procedure for 20 to 30 minutes|
|Clinical outcomes||5. CNB can be used as alternative to FNA for thyroid nodules with non-diagnostic cytology in previous FNA|
|6. CNB may be used as alternative to FNA for thyroid nodules with atypia (follicular lesion) of undetermined significance in previous FNA|
|7A. CNB has advantages to differentiate encapsulated follicular neoplasm from non-neoplastic nodule|
|7B. CNB cannot differentiate follicular thyroid carcinoma from follicular adenoma|
|8. CNB may be used as alternative to FNA for calcified thyroid nodules|
|9. CNB may achieve low rates of non-diagnostic and inconclusive results for initially detected thyroid nodules. However, utility of CNB as first-line diagnostic tool for these nodules is uncertain based on current evidence|
|10A. CNB can be used as alternative to FNA in patients with clinical and radiological features of uncommon malignancies (anaplastic carcinoma, lymphoma, or medullary carcinoma)|
|10B. CNB can be used as alternative to FNA for thyroid nodules with US–cytology discordance in previous FNA|
|Complications||11. CNB is safe, well-tolerated, and associated with low incidence of complications when performed by experienced operators|
CNB = core needle biopsy, FNA = fine-needle aspiration, US = ultrasound
5. With advances in core biopsy devices, spring-activated single- or double-action needles have been applied to thyroid nodule diagnosis.
6.In addition, widespread use of high-resolution US enables accurate diagnosis and minimization of complications.
7. Core needle biopsy (CNB) has been reported to be an effective and safe biopsy method for thyroid nodules. CNB has the potential to overcome the limitations of FNA permitting feasible immunochemical staining.
Core needle biopsy could be an alternative to FNA in the evaluation of thyroid nodules in selected cases.
9. Devices CNB devices have a smaller bore (usually 18–21 gauge) and spring-activated needles.
10.Large-needle biopsy, performed without US guidance with a large-bore needle, is not recommended for thyroid nodules.
11.The proper CNB needle conditions for thyroid nodules The use of 18–21-gauge needles is universal for thyroid nodules, 18-gauge needles have been mainly used in Korea.
12. Length of the stylet, namely, the penetration length, can be selected according to the size of nodule and is usually 1–2 cm.
Core needle device.
A. Stylet and specimen notch (arrows). B. Cutting cannula.
13.Core needle biopsy needles are composed of two needles, the stylet and the cutting cannula. The stylet or inner needle has an approximately 2-mm-long sharply sloped tip to penetrate tissue and a specimen notch for holding the sampled tissue. The cutting cannula or the outer blade is the outer component of the CNB needle and plays a role in cutting the tissue and placing it on the specimen notch.
14.The semi-automated needle enables a relatively safe procedure, despite the presence of a risky aspect because operators manually push the stylet into the tissue.
15.There are various kinds of spring power. Although a device with a strong spring can better penetrate hard tissues such as calcifications or fibrosis, it has higher potential for injury of normal tissue or vessels.
16.The amount of tissue obtained depends on the needle thickness and the length of the specimen notch.
17.[Recommendation 2] Modern CNB devices, particularly 18–21-gauge, spring-activated, core needles, are recommended for the procedure.
18.[Recommendation 3] Patients with bleeding tendency, such as those taking anticoagulation medications or with disorders affecting the coagulation cascade, should be thoroughly evaluated and any problems corrected before CNB.
19. Core needle biopsy should be performed by experienced operators under US guidance.
20. Operators should determine the appropriate type of CNB needle and access route via preprocedural US evaluation, which is also important for improving safety and diagnostic accuracy.
21.Although no standard technique for thyroid CNB has been established, the KSThR recommend the following techniques for effective and safe procedures.
22. Experience is one of the most important factors for CNB safety.dles: a free-hand technique or a US probe-guiding device.
23.Patients lie down in a supine position with their neck fully extended. Local anesthesia with 1% lidocaine applied using a finer needle through the route is recommended. Figure 2 shows a CNB procedure on US. To pass through the skin and thyroid capsule, a snapping movement of the wrist is favored for effective rapid needle passage and to reduce pain.
24.Skin puncture can be effectively performed without skin incision by introducing the needle through the entry hole created by the needle or by direct skin puncture with a rapid snapping movement of the wrist with the core needle. The entire length of the CNB needle must be monitored during the procedure and the needle should remain parallel to the axis of the US probe during the procedure, which is mandatory for the optimal US guidance of CNB.
25. CNB may also be technically difficult when there is a small nodule located in the deep posterior area of the thyroid gland. In this situation, first insert a stylet into the nodule by manually advancing the stylet and then elevate the nodule with the inserted stylet. The direction of firing would be changed after positioning the stylet to a safer lateral or oblique lateral direction and, then, the cutting cannula can be safely fired.
26.Sometimes, thyroid nodules containing severe fibrosis and/or heavy calcification may be too hard to be penetrated by a CNB needle. To successfully obtain samples from such hard nodules, operators can try to stab the nodule with a needle tip to identify a weak point, use a double-action needle with spring power, and/or adjust the specimen notch direction. Sometimes, the nodule is so hard that the needle may be deflected and damage adjacent structures. Thus, before sampling hard nodules, careful evaluation of the surrounding structures is vital.
(A) CNB should be performed by experienced operators under US guidance.
(B) Manual compression of the biopsy site should be performed immediately after the procedure for 20 to 30 minutes.
27. [Recommendation 5]
Core needle biopsy can be used as an alternative to FNA for thyroid nodules with non-diagnostic cytology in previous FNA.
Core needle biopsy may be used as an alternative to FNA for thyroid nodules with atypia (follicular lesion) of undetermined significance in previous FNA.
(A) CNB has advantages to differentiate encapsulated follicular neoplasms from non-neoplastic nodule.
(B) CNB cannot differentiate follicular thyroid carcinoma from follicular adenoma.
Core needle biopsy may be used as an alternative to FNA for calcified thyroid nodules.
Core needle biopsy may achieve low rates of non-diagnostic and inconclusive results for initially detected thyroid nodules. However, the utility of CNB as a first-line diagnostic tool for these nodules is uncertain based on current evidence.
(A) CNB can be used as an alternative to FNA in patients with clinical and radiological features of uncommon malignancies (anaplastic carcinoma, lymphoma, or medullary carcinoma).
(B) CNB can be used as an alternative to FNA for thyroid nodules with US–cytology discordance in previous FNA.
33.Complications CNB is safe, well-tolerated, and associated with a low incidence of complications when performed by experienced operators.
34.The reported complication rate ranges from 0 to 4.1%, with the major complication rate ranging from 0 to 1.9%.
35.Because CNB is performed under real-time US guidance, serious complications seem to be rare.
36.Nonetheless, various complications may occur, including hematoma, hoarseness, infection, hemoptysis, edema, vasovagal reaction, and dysphagia.
37.Besides these complications, a recent large single-center study (6687 thyroid nodules of 6169 patients) found low rates of major and minor complications (4/6169 [0.06%] and 49/6169 [0.79%], respectively) and no procedure-related death or sequelae.
38. Two recent studies compared the pain and tolerability of FNA and CNB and concluded that the two procedures are similar in terms of pain and tolerability.
39. [Recommendation 11]
Core needle biopsy is safe, well-tolerated, and associated with a low incidence of complications when performed by experienced operators.
The KSThR has suggested these recommendations to improve the efficacy and safety of CNB in the diagnosis of thyroid nodules. The operators performing CNB should know the basic CNB techniques and perithyroidal anatomy and have experience with image-guided interventions.