Comparison of ultrasound-guided biopsy technique for thyroid nodules with respect to adequacy of cytological material

Thyroid US-guided FNA techniques: A prospective,randomized controlled study

BACKGROUND

Thyroid nodules are common in the general population. Ultrasonography is the most efficient diagnostic approach to evaluate thyroid nodules. The US FNAC procedure can be performed using either the short axis (perpendicular), or a long axis (parallel) approach to visualize the needle as it is advanced toward the desired nodule. The main aim of this study was to compare the percentage of non-diagnostic results between the long and short axis approach.

METHODS

A prospective study that included a randomized controlled trial and was divided into two arms-the short axis and the long axis-was conducted. A total of 245 thyroid nodules were collected through the fine needle aspiration cytology, performed with ultrasound, from march 2021 to march 2022. The patient's demographic information were collected and also nodules characteristics.

RESULTS

Of 245 nodules sampled, 122 were sampled with the long axis method, while 123 with the short axis method. There is not significantly less non diagnostic approach with either method compared to the other (11.5 % vs 16.3 % respectively).

DISCUSSION

Previous studies came to the conclusion that the long axis method yields fewer non diagnostic samples. This study evaluated the two FNA approaches which were proceeded by the same physician who is expert in both techniques.

CONCLUSION

The US FNAC performed in the long axis approach will not produce more conclusive results and less non diagnostic results (Bethesda category 1) than the short axis approach one.

Factors Influencing the Sample Adequacy of Ultrasound-Guided Fine-Needle Aspiration from Solid Thyroid Nodules for Liquid-Based Cytology: A Demographic, Sonographic, and Technical Perspective

Background and Objectives: To identify factors that influence the sample adequacy of solid thyroid nodules based on ultrasound-guided fine-needle aspiration (FNA) with subsequent liquid-based cytology. Materials and Methods: We retrospectively reviewed 855 patients who underwent ultrasound-guided FNA at our hospital between July 2019 and July 2020. The final analysis included 801 solid thyroid nodules in 801 patients. After reviewing the demographic data, ultrasonic features, and FNA technique-related factors, we defined 14 potential variables. For cytological results, the Bethesda categories II−VI were defined as adequate sample results. Univariate and multivariate analyses were performed to identify factors that influenced sample adequacy. Results: The adequate sample rate was 87.1%. The univariate analysis showed that four factors were related to adequate sampling in patients with thyroid FNA. These factors included age (p < 0.001), nodule orientation (p = 0.0232), calcification (p = 0.0034), and operator experience (p = 0.0286). After the multivariate analysis, five independent factors were identified to improve the diagnostic results of FNA for solid thyroid nodules: (1) the presence of Hashimoto’s thyroiditis (odds ratio (OR) = 1.810; 95% confidence interval (CI): 1.076−3.045; p = 0.0254), (2) a taller-than-wide orientation (OR = 2.038; 95% CI: 1.260−3.296; p = 0.0037), (3) the presence of calcification (OR = 1.767; 95% CI: 1.115−2.799; p = 0.0153), (4) four needle passes to obtain material (OR = 1.750; 95% CI: 1.094−2.799; p = 0.0196), and (5) an experienced operator (OR = 0.561; 95% CI: 0.319−0.987; p = 0.0451). Conclusions: A taller-than-wide orientation, the presence of calcification, and the presence of Hashimoto’s thyroiditis were found to affect the sample adequacy of ultrasound-guided FNA with liquid-based cytology. The sample adequacy could be improved when FNA is performed with four needle passes by experienced doctors.

Battle of the axes: simulation-based assessment of fine needle aspiration biopsies for thyroid nodules

Importance

Ultrasound-guided fine-needle aspiration biopsies (UGFNA) play a crucial role in the diagnosis of thyroid nodules. There are two techniques for performing an UGFNA: short-axis technique and long-axis technique. There is sparsity in the literature regarding the differences between these two techniques.

Objective

To compare the efficiency between long-axis and short-axis thyroid UGFNA techniques in trainees. Our secondary outcomes were to define the comfort level and learning curves of trainees.

Design

A longitudinal prospective cohort study, completed from December 2018 to November 2019, using the Blue Phantom Thyroid Model© for UGFNA. Face and construct validity of the model were verified. Residents completed UGFNA on an assigned nodule using both long-axis and short-axis techniques, the order of which was sequentially allocated. The rate and time to successful biopsy were obtained for both techniques. Biopsy attempts were repeated to establish learning curves.

Setting

Single-center study.

Participants

Fourteen Otolaryngology—Head & Neck Surgery residents at the University of Toronto.

Main outcome measure

Biopsy success and efficiency for novice learners completing UGFNA on a simulated thyroid model using long-axis and short-axis techniques.

Results

A trend towards higher odds of successful biopsy using the long-axis technique with no difference in procedure duration was observed (OR = 2.2, p = 0.095, CI = 0.87–5.39). Learning curve graphs appeared heterogenous according to trainee level. Trainees found the long-axis technique easier to perform (10/14, 71%), and the simulator valuable for learning (12/14, 86%).

Conclusion

Thyroid UGFNA using the long-axis technique may have an increased success rate and is generally favored by trainees for being easier to perform. Thyroid simulators have the potential to increase learner comfort and efficiency with UGFNA.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40463-022-00587-5.

US-guided FNA techniques for thyroid nodules is the short axis better than the long axis?

BACKGROUND

Ultrasound-guided fine needle aspiration cytology (FNAC US) has been proven to be an accurate and efficient tool in thyroid nodule evaluation. Thyroid nodule aspiration can be acquired with either of two techniques: the short axis, in which only the tip of the needle is observed, and the long axis, in which the entire length of the needle is observed. Our retrospective study aimed to compare the adequacy of the two techniques.

METHODS

FNAC US was performed in 538 thyroid nodules between January 2019 and December 2021. Data on the technique and the diagnostic accuracy were collected.

RESULTS

A total of 273 nodules were aspirated using the long axis technique, and 265 nodules were aspirated using the short axis technique. The diagnostic adequacies of the long axis technique were significantly higher than those of the short axis technique (92 % versus 86 %, respectively, p < 0.025).

CONCLUSION

In our study, the long axis technique provided more accurate cytological evaluation than the short axis technique.

LEVEL OF EVIDENCE

level 3.

High-Score US-Suspicious Subcentimeter Thyroid Nodules: What Factors Affect Adequate Sampling of US-Guided Fine-Needle Aspiration Biopsy?

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is diagnostic standard for thyroid nodules. However, the influence of adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules is not known well.

OBJECTIVES

To assess the factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules.

METHODS

Three hundred and forty-nine consecutive US-guided FNAB procedures were performed in 344 patients with subcentimeter thyroid nodules. The adequate sample rate was analyzed for all nodules on the basis of nodule-related and technical factors. The factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules were determined by multivariate logistic regression.

RESULTS

The adequate sample rate increased with larger nodules (72.7% for 3-6 mm nodules and 84.9% for 7-10 mm nodules (P=0.007)). The adequate sample rate was 63.9%, 81.3%, and 90.6% in nodules with macrocalcifcation, microcalcification, and no calcification, respectively (P < 0.001). The adequate sample rate was 71.8% for biopsies performed with a perpendicular needle path and 85.0% with a parallel needle path (P=0.004). The significant factors affecting adequate sample rate of US-guided FNAB for subcentimeter thyroid nodules were nodule size (P < 0.001; odds ratio (OR) for 7-10 mm nodules was approximately 3.0 times higher than that for 3-6 mm nodules), calcification (P < 0.001; OR for nodules without calcification was approximately 5.3 times higher than that for the nodules with macrocalcification), and needle path (P=0.044; OR for the use of the parallel needle path was about 1.8 times higher than that for the perpendicular needle path).

CONCLUSION

Nodule size, calcification, and needle path were the determinants of sample adequacy. The adequate sample rate was higher in larger nodules, in nodules without calcification, and upon using a parallel needle path for biopsy.

Nondiagnostic cytological results on ultrasound-guided fine needle aspiration: Does the thyroid nodule depth matter?

OBJECTIVE

To evaluate whether thyroid nodule depth and other ultrasound features can predict nondiagnostic cytological results on ultrasound-guided fine needle aspiration.

MATERIAL AND METHODS

This retrospective study included 412 thyroid nodules that underwent ultrasound-guided fine needle aspiration from 2014 to 2015. The nodules were classified as nondiagnostic and diagnostic by the cytopathological results. Clinical information of the patients (ie., age, sex) and ultrasound features (ie., size, depth, calcification, cystic content, vascularity) of the nodules were recorded and compared between the nondiagnostic group and diagnostic group.

RESULTS

Age and sex were not significantly different between the nondiagnostic group and diagnostic group (P > 0.05). Nodule depth >15 mm (OR, 7.128; P < 0.001), peripheral rim calcification (OR, 5.725; P = 0.01) and cystic content >50% (OR, 2.995; P = 0.018) were factors for the nondiagnostic ultrasound-guided fine needle aspiration cytopathological results. Macrocalcification in the nodule sized 5-10 mm was associated with the nondiagnostic results (P = 0.04). Nodule size and vascularity were not associated with the nondiagnostic results (P > 0.05).

CONCLUSIONS

Nodule depth >15 mm, peripheral rim calcification and cystic content >50% were three independent predictors of the nondiagnostic cytopathological results. Macrocalcification in the nodule sized 5-10 mm was also associated with the nondiagnostic results.

Ultrasound-guided fine needle aspiration of thyroid nodules: a consensus statement by the korean society of thyroid radiology

Ultrasound (US)-guided fine needle aspiration (US-FNA) has played a crucial role in managing patients with thyroid nodules, owing to its safety and accuracy. However, even with US guidance, nondiagnostic sampling and infrequent complications still occur after FNA. Accordingly, the Task Force on US-FNA of the Korean Society of Thyroid Radiology has provided consensus recommendations for the US-FNA technique and related issues to improve diagnostic yield. These detailed procedures are based on a comprehensive analysis of the current literature and from the consensus of experts.

Examining the Bethesda criteria risk stratification of thyroid nodules

BACKGROUND

The Bethesda criteria are proposed for appropriate stratification of malignancy risk in thyroid nodules, but controversy exists regarding their accuracy and reliability in decision making. Additionally, previous studies have suggested higher rates of both malignancy and false negative fine needle aspiration biopsy (FNA) associated with increasing nodule size. This study aims to determine the accuracy of ultrasound (US)-guided FNA using the current Bethesda criteria in surgical practice. We also aimed to investigate the relationship between nodule size and malignancy.

METHODS

A retrospective analysis of US-guided FNAs by a single surgeon during a 4.5 year period. FNA results using Bethesda criteria were compared to final surgical pathology.

RESULTS

611 patients with thyroid nodules underwent US-guided FNA. FNA results in 375 subsequently excised thyroid nodules were recorded according to the Bethesda criteria: 192 (51%) benign, 65 (17%) atypia of unknown significance/follicular lesion of undetermined significance (AUS/FLUS), 42 (11%), suspicious for follicular neoplasm (SFN), 17 (5%) suspicious for malignancy (SM), 28 (8%) malignancy, and 31 (8%) non-diagnostic. Malignancy was confirmed by surgical pathology in 15%, 34%, 50%, 88%, 100%, and 39% of the above groups respectively. Sensitivity, specificity, and false-negative rate were 61%, 99%, and 15% respectively. No correlation existed between the size of nodules with indeterminate FNA results and malignancy rate (p=0.89), or size of nodules with non-diagnostic FNA and malignancy rate (p=0.50).

CONCLUSION

The current Bethesda risk stratification system underestimated malignancy rates in benign, indeterminate and non-diagnostic cytopathologic categories in our experience. There was no positive linear correlation between nodule size and malignancy rate in these cytopathologic categories.

Resident experience increases diagnostic rate of thyroid fine-needle aspiration biopsies

RATIONALE AND OBJECTIVES

The aim of this study was to determine whether the diagnostic yield of thyroid fine-needle aspirations (FNAs) changes over the course of residency training.

MATERIALS AND METHODS

We identified 5418 ultrasound-guided thyroid nodule FNAs performed in our radiology department from 2004 through 2012. For each FNA, we recorded if the FNA was performed by a resident and if so the name of the resident and supervising attending radiologist. For each resident, we determined the level of training based on their graduation year from our residency program and the date of the FNA as well as prior surgical training and if they completed subsequent interventional radiology fellowship. Pathology reports were reviewed, and FNAs were classified as diagnostic or nondiagnostic (ND). Generalized mixed models were used to assess ND rate with postgraduate years, including residents with and without prior surgical training or if they subsequently completed an interventional radiology fellowship.

RESULTS

Of the 5418 thyroid FNAs, 3164 (58.4%) were performed by a radiology resident under the direct supervision of an attending physician. There was a significant decrease in ND rate as postgraduate years increased (P < .05). A significant decrease in ND rate was found as postgraduate years increased for residents without prior surgical training (P = .0007) or subsequent training in interventional radiology (P = .0014); however, no significant decrease was found for residents with surgical training (P = .37) or completing an interventional radiology fellowship (P = .08). In addition, no significant difference was found for ND rate between postgraduate year 4 (PGY4) and PGY5 (P > .05).

CONCLUSIONS

ND thyroid FNA rates progressively decrease with training level, suggesting that early and continued participation in procedures throughout residency improves outcomes. This is particularly true for residents without prior surgical training or subsequent interventional radiology fellowship.

Low nondiagnostic rate for fine-needle capillary sampling biopsy of thyroid nodules: a singular experience

OBJECTIVES

This study examined the hypothesis that sonographically guided fine-needle capillary thyroid biopsies performed by an experienced operator and with constant technique on nodules that meet the Society of Radiologists in Ultrasound criteria warranting biopsy can result in a nondiagnostic rate that is significantly lower than prior published reports.

METHODS

We retrospectively reviewed the sonographic and pathologic reports from 228 consecutive sonographically guided fine-needle capillary thyroid biopsies performed during a 3-year interval by a single operator with more than 15 years of experience performing fine-needle capillary thyroid biopsies. There were no exclusion criteria. Sonographic and pathologic reports from all nodules biopsied were included in the analysis. The radiologist's protocol included 6 fine-needle capillary biopsies, each with 20 passes of the needle into the periphery and/or solid components of the nodule. The cytologic specimens were reviewed off-site in adherence with the Bethesda system for reporting thyroid cytopathologic findings and classified as diagnostic or nondiagnostic. The nondiagnostic rate in this study was compared with the nondiagnostic rates in prior published reports.

RESULTS

Among the 228 fine-needle capillary thyroid biopsies performed during the study interval, cytologic analysis showed 1 nondiagnostic biopsy, yielding a nondiagnostic rate of 0.4%. This rate was significantly lower than previously published reports (P < .001).

CONCLUSIONS

Sonographically guided fine-needle capillary biopsies of the thyroid performed by an experienced radiologist can result in a nondiagnostic rate of less than 1%. This finding warrants further investigation into the reasons for the discrepancy between the results of this study and other previous reports.