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

Nondiagnostic Fine Needle Aspiration of Thyroid Nodules: Review of Predisposing Factors

OBJECTIVE

Fine needle aspiration (FNA) of thyroid nodules is the gold standard screening test for thyroid malignancy. Unfortunately, FNA may produce insufficient material for diagnosis. If nodules requiring FNA with a higher risk for nondiagnostic (ND) cytology could be identified pre-procedure, this might allow better patient guidance and potentially facilitate an altered approach to FNA.

METHODS

The literature investigating risk factors for ND cytology was reviewed, including studies of patient factors, sonographic or nodule factors, and procedural factors. Twenty-five studies that included assessment of at least two potential factors in ND outcomes for initial FNA were identified. Individual factors were evaluated in terms of the general consensus of studies reporting either a positive significant association with ND cytology or no association.

RESULTS

Most patient and nodule factors lack consensus as far as their association with ND cytology across these studies. Factors where there are some consensuses include practitioner experience, depth of nodule, and cystic content; however, hypervascularity of the nodule does not appear to have a consensus.

CONCLUSION

A number of study design improvements suggested by this review could realistically be incorporated into higher powered future studies. Novel factors such as tissue composition anterior to the nodule or the age of the patient could also be investigated in future work. Operator experience is the most convincing procedural factor, and approaches to future studies of the FNA technique itself are proposed. That said, the factors with consensus among studies can be seen leading candidates for this future research, and the published studies illuminate a number of as yet unexplored factors that could in many cases be studied retrospectively.

Ultrasound features affecting the sample adequacy after fine-needle aspiration of thyroid nodules with different risk stratification

BACKGROUND

The inadequacy samples caused by the internal characteristic structure of thyroid nodules are difficult to be solved.

OBJECTIVE

To evaluate the ultrasound features affecting the sample adequacy after fine-needle aspiration (FNA) of thyroid nodules with different risk stratification.

METHODS

592 thyroid nodules that underwent ultrasound-guided FNA were included in this retrospective study. The sample obtained by FNA were classified as inadequacy and adequacy according to the cytopathological results. Ultrasound features (ie., size, position, cystic predominance, composition, echo, shape, margin, and superficial annular calcification status) of the nodules were recorded and compared between the inadequacy sample group and adequacy sample group.

RESULTS

Multiple logistic regression shows that preponderant cystic proportion (OR, 0.384; P = 0.041), extremely hypoechogenicity and hypoechogenicity (OR, 6.349; P = 0.006) were the independent influencing factors of inadequate samples after FNA in benign expected nodules. In addition, nodule size ≤10 mm (OR, 1.960; P = 0.010) and superficially annular calcification (OR, 4.600; P <  0.001) were independent influencing factors for inadequate samples after FNA in malignant expected nodules.

CONCLUSION

The ultrasound features of hypoechogenicity or high cystic proportion in benign expected nodules and that of small size or annular calcification in malignant expected nodules were the risk factors for inadequacy samples by US-guided FNA.

Ultrasound-Guided Fine Needle Aspiration of Deep Thyroid Nodule: Is There a Correlation between the Nodule's Depth and Nondiagnostic Results?

Objective

To evaluate whether thyroid nodule depth correlates with nondiagnostic results in ultrasound-guided fine needle aspiration cytopathology.

Background

Many factors correlate with nondiagnostic ultrasound-guided fine needle aspiration cytology (FNAC) results, including older age, macrocalcification, small-sized nodules, aspirin medication, and cystic portion in more than 50% of the thyroid nodules. However, there are few studies which have examined whether there is a relationship between the depth of nodules and the percentage of nondiagnostic results in cytology (Bethesda category I). We conducted this study in order to investigate if such a correlation exists.

Materials and Methods

FNAC was performed on 283 thyroid nodules between January 2019 and December 2020. Cytological analyses of the nodules were reviewed and sorted as nondiagnostic and diagnostic according to the Bethesda score. Patient files and ultra sound (US) scans were reviewed for clinical information (such as age, sex, and ethnic group) and sonographic features of nodules (such as depth, size, cystic portion, type of calcification, and echogenicity) and were compared between the nondiagnostic and diagnostic nodule results. The depth of a nodule was calculated as the shortest distance from the skin to the most superficial border of the nodule in the axial plane, using our medical center's computer program, which allows reviewing all saved shots of the US scan.

Results

Age, sex, and ethnicity were not significantly different between the nondiagnostic group and the diagnostic group (p > 0.05). Nodule diameter, cystic portion, calcification, and echogenicity were also not associated with the frequency of nondiagnostic results. The depth of nodules ≥9 mm was correlated with nondiagnostic US-guided FNA cytological results (OR = 2.55, p=0.018).

Conclusions

Deep thyroid nodules correlated with nondiagnostic US-guided FNA cytological results. Further studies are needed for optimizing the approach to deep thyroid nodules in order to improve the efficacy of FNA in deep thyroid nodules.

Independent risk factors and feasibility of ultrasound diagnosis of ultrasound-guided non-cytologically diagnostic thyroid nodules

BACKGROUND

To explore the independent risk factors and feasibility of ultrasound diagnosis of ultrasound-guided non-cytologically diagnostic thyroid nodules.

METHODS

This study included 200 patients with thyroid nodules that were diagnosed or suspected of being Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules between January 2017 and January 2019. All patients received surgical treatment and pathological diagnosis, and were divided into a cytologically diagnostic group and a non-cytologically diagnostic group based on whether they could be diagnosed by ultrasound-guided fine needle aspiration cytology (UG-FNAC). Patients were further divided into benign and malignant groups according to the results of surgical pathology. Logistic regression analysis was used to clarify the risk factors that could not be cytologically diagnosed in TI-RADS 4 nodules. For the diagnosis of benign and malignant nodules, we combined contrast-enhanced ultrasound (CEUS) and ultrasound elastography (UE) to establish a joint scoring strategy. The diagnostic value of the joint scoring strategy was evaluated by receiver operating characteristic (ROC) curve.

RESULTS

A total of 216 TI-RADS type 4 nodules were detected in 200 patients. Among them, 40 nodules were included in the non-cytologically diagnostic group, and 176 nodules were included in the cytologically diagnostic group. The multi-parameter logistic regression showed that: aspect ratio <1, irregular edge, scattered coarse calcification, middle layer, and lower layer were independent influencing factors leading to undiagnosed puncture cytology. Among the 216 nodules in 200 patients, 168 were pathologically diagnosed as malignant nodules (malignant group), and 48 nodules were diagnosed as benign nodules (benign group). According to the joint scoring strategy, the distribution of comprehensive scores changes significantly at 5-6 scores while in malignant nodules, the distribution of comprehensive scores changes significantly at 6-7 scores. ROC curve analysis showed that the diagnostic value was the highest when '6 scores' was used as the critical point for diagnosis [area under curve (AUC) =0.893, P<0.05].

CONCLUSIONS

The combined scoring strategy of CEUS and UE was an effective method to diagnose TI-RADS4 nodules could not be diagnosed by UG-FNAC.

Application Value of Ultrasound-Guided Fine Needle Aspiration Cytological Examination and Ultrasound Evaluation

In this paper, chronic inflammatory cell infiltration was seen during this period. The reason for the false-positive result may be the atypical proliferation of cells caused by chronic inflammatory stimulation with malignant cytology. 12 cases of false negative results, including 2 cases of type I nodules, 10 cases of type III nodules, postoperative histology and pathology were papillary carcinoma, there are many reasons for false negative results, including the size of the nodules, the puncture operator, the technical level, internal tissue composition and properties of the nodules all affect the accuracy of puncture and cytopathology results. The satisfaction of puncture specimens of each group was calculated and compared. For thyroid nodules with the maximum diameter ≤5 mm, the satisfaction rate of puncture specimens was 87.2%, and the diagnostic sensitivity and accuracy of ultras guided fine needle aspiration biopsy were relatively low. Cytological results were in poor agreement with postoperative histological and pathological results, so it was recommended to take active follow-up for thyroid nodules with the maximum diameter ≤5 mm to reduce unnecessary puncture. The overall puncture success rate is relatively high, ≤10 mm low-echo nodules or even ≤5 mm nodules can be cytological puncture, especially the kind of close to the capsule, trachea and recurrent laryngeal nerve nodules, for the largest diameter of >5 mm, the satisfaction rate of puncture specimens is relatively high is 93.2%. Moreover, the sensitivity and accuracy of ultrasound guided fine needle aspiration biopsy were relatively high, and the cytological results were in good agreement with the postoperative histological and pathological results. Therefore, it was feasible to confirm the diagnosis of suspected malignant nodules by ultrasound. The diagnostic in each group and the consistency between cytological diagnosis and histological diagnosis were analyzed by comparing the histological and pathological results after surgery. Ultrasound-guided fine needle aspiration biopsy can be used more effectively in clinical practice.

The Diagnostic Role of Computed Tomography for ACR TI-RADS 4-5 Thyroid Nodules With Coarse Calcifications

Objectives: Coarse calcifications are prone to cause echo attenuation during ultrasonography (US) and hence affect the classification of benign and malignant nodules. This study aimed to investigate the diagnostic role of computed tomography (CT) for differentiating the American College of Radiology (ACR) Thyroid Imaging Reporting and Data System (TI-RADS) 4–5 nodules with coarse calcifications.

Methods: CT data of 216 ACR TI-RADS 4–5 nodules with coarse calcifications confirmed by surgery and pathology in 207 patients were analyzed retrospectively. Halo sign, artifacts, and CT values (i.e., Hounsfield unit) of the nodules were determined by two radiologists. Univariate analysis and binary logistic regression were used to determine the relationship of halo sign, artifact, and CT value with benign nodules. A predictive model for benign nodules with coarse calcifications was then constructed. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of halo sign, artifact, CT value, and logistic regression model.

Results: Of the 216 ACR TI-RADS 4–5 nodules with coarse calcifications, 170 were benign and 46 were malignant. There were 92 benign and 7 malignant nodules with halo sign (χ² = 22.067, P < 0.001), and 79 benign and 10 malignant nodules with artifacts (χ² = 9.140, P < 0.001). The CT values of benign and malignant nodules were 791 (543–1,025) Hu and 486 (406–670) Hu, respectively (Z = −5.394, P < 0.001). Binary logistic regression demonstrated that the halo sign, artifact, and CT value were independent predictors for benign nodules with coarse calcifications. The area under the ROC curve (AUC) of halo sign, artifact, CT value and regression model for predicting benign nodules with coarse calcifications were 0.776, 0.711, 0.784, and 0.850, respectively, and the optimal threshold of CT value was 627.5 Hu.

Conclusion: Halo sign, artifact, and CT value > 627.5 Hu were helpful for identifying ACR TI-RADS 4–5 thyroid benign nodules with coarse calcifications. The diagnostic performance of the logistic regression model was higher than that of any single indicator. Accurate identification of these indicators could identify benign nodules and reduce unnecessary surgical trauma.