Shear wave elastography of thyroid nodules in routine clinical practice: preliminary observations and utility for detecting malignancy

Objective

To evaluate real-time shear wave ultrasound elastography (SWE) for characterizing focal thyroid lesions in routine clinical practice.

Methods

Seventy-four patients with 81 focal thyroid lesions undergoing conventional US with needle cytology also underwent SWE. Absolute and relative SWE stiffness measurements on colour-coded elastograms were correlated with cytology and their discriminatory performances assessed.

Results

Seventeen nodules were malignant (13 papillary, 4 other cancers), 45 benign (43 hyperplastic nodules, 2 focal thyroiditis), 5 indeterminate (“follicular lesions”), and 5 had inadequate cytology. SWE results were higher in malignant than benign nodules (P values 0.02–0.05) although their discriminatory performances were mediocre (AUCs 0.58–0.74). The most accurate SWE cut-off, 34.5 kPa for a 2-mm region of interest, achieved 76.9?% sensitivity and 71.1?% specificity for discriminating papillary cancer from benign nodules. No thresholds produced high sensitivity without lowering specificity appreciably, and vice versa. Nodule size correlated with SWE for benign nodules (P?<?0.01). Intranodular cystic change or calcification did not influence SWE. Qualitatively, elastographic artefacts and foci lacking colour elasticity signal occurred in some solid nodules.

Conclusion

Although malignant nodules are generally stiffer than benign nodules, the precision results do not suggest a definitive role for SWE, at present, in identifying or excluding thyroid malignancy.

Key Points

? Shear wave ultrasound elastography (SWE) offers new insight into thyroid disease. ? Papillary cancers have higher SWE indices (equating to higher stiffness) than benign nodules. ? SWE appears limited in terms of identifying or excluding thyroid malignancy accurately. ? Vertically aligned elastographic artefacts can occur in thyroid SWE. ? Areas lacking SWE colour signal can occur in some solid thyroid nodules.     

Quantitative assessment of shear-wave ultrasound elastography in thyroid nodules: diagnostic performance for predicting malignancy

Objectives

To evaluate the predictability of shear-wave ultrasound elastography (SWE) for thyroid malignancy and to compare the diagnostic performances of SWE and B-mode US.

Methods

Retrospective review of 99 patients who underwent SWE before US-guided fine-needle aspiration of thyroid nodules was performed. SWE elasticity indices of the mean (E_mean ), maximum (E_max), and minimum (E_min) of nodules were measured. Diagnostic performance of SWE was compared with that of B-mode US.

Results

Among a total of 99 nodules, 21 were papillary thyroid carcinoma (PTC) and 78 were benign. E_mean, E_max, and E_min were significantly higher in PTCs than in benign nodules (P?<?0.001). Sensitivity and specificity for predicting malignancy were 76.1 %, 64.1 % with E_max (65 kPa), 61.9 %, 76.1 % with E_min (53 kPa), and 66.6 %, 71.6 % with E_mean (62 kPa). Areas under the ROC curves (Az) of SWE values were not significantly different from those of US categories on B-mode US. However, combining E_mean and E_min with B-mode US of probably benign lesions improved the specificity (P?=?0.02, 0.007) for predicting PTC.

Conclusions

The quantitative parameter of SWE was significantly higher in PTC than in benign nodules, and combined use of quantitative SWE and B-mode US provided higher specificity for predicting malignancy.

Key Points

? Quantitative shear-wave elastography (SWE) helps differentiate benign from malignant nodules ? SWE and conventional ultrasound have comparable diagnostic performance for predicting thyroid malignancy ? Combined quantitative SWE and B-mode ultrasound is highly specific for thyroid malignancy     

Diagnostic accuracy of fine-needle aspiration versus core-needle biopsy for the diagnosis of thyroid malignancy in a clinical cohort

Objectives

To retrospectively compare the accuracy of fine-needle aspiration (FNA) and core-needle biopsy (CNB) for the diagnosis of thyroid malignancy

Methods

We evaluated the results of FNA and CNB in 555 consecutive thyroid nodules with final diagnoses (malignancy 318, benign 237). All patients underwent FNA and CNB simultaneously for each nodule. We assessed the sensitivity, specificity and accuracy of FNA, CNB and FNA/CNB for the diagnosis of thyroid malignancy.

Results

The sensitivity of FNA, CNB and FNA/CNB for thyroid malignancy was 68.6%, 86.8% and 90.6%, specificity 100%, 99.2% and 99.2%, and accuracy 82.0%, 92.1% and 94.2%, respectively. The sensitivity and accuracy of CNB or FNA/CNB for thyroid malignancy were significantly higher than those of FNA (P?P?Conclusions Our clinical cohort data demonstrated that CNB was more accurate for the diagnosis of thyroid malignancy than FNA, and FNA/CNB was more accurate than CNB alone in small thyroid nodules. CNB will play a complementary role in optimal surgical decision-making and the management of thyroid nodules.

Key Points

? CNB was more accurate for the diagnosis of malignancy than FNA. ? Combined FNA/CNB was more accurate than CNB alone in small thyroid nodules. ? CNB should play at least a complementary role in managing thyroid nodules.     

MRI-guided percutaneous coaxial cutting needle biopsy of small pulmonary nodules: feasibility

Objectives

To prospectively evaluate the feasibility, safety and accuracy of magnetic resonance imaging (MRI)-guided percutaneous coaxial cutting needle biopsy of small (≤2.0 cm in diameter) pulmonary nodules.

Methods

Ninety-six patients (56 men and 40 women) with 96 small lung nodules underwent MRI-guided percutaneous coaxial cutting needle biopsy. These lesions were divided into two groups according to maximum nodule diameters: 0.5–1.0 cm (n?=?25) and 1.1–2.0 cm (n?=?71). The diagnostic accuracy, sensitivity and specificity were calculated, and comparison of the two groups was performed using Fisher's exact test.

Results

All specimens obtained were sufficient for diagnosis. Histological examination of needle biopsy revealed 64 malignant, 30 benign and 2 indeterminate nodules. The final diagnoses from surgery or clinical follow-up were 67 malignant nodules and 29 benign nodules. The diagnostic performance of MRI-guided percutaneous coaxial cutting needle biopsy in diagnosing malignant tumours was as follows: accuracy, 97 %; sensitivity, 96 %; specificity, 100 %; positive predictive value, 100 %; and negative predictive value, 91 %. There was no significant difference between the two groups (P?>?0.05, Fisher's exact test). No serious complications occurred.

Conclusions

MRI-guided percutaneous coaxial cutting needle biopsy is a safe and accurate diagnostic technique in the evaluation of small lung nodules.

Key Points

? MRI-guided biopsy helps clinicians to assess patients with small lung nodules. ? Differentiation of malignant and benign nodules is possible with 97?% accuracy. ? MRI guidance enables accurate lung biopsy without ionising radiation. ? No serious complications occurred in MRI-guided lung biopsy.     

Radiofrequency ablation of benign non-functioning thyroid nodules: 4-year follow-up results for 111 patients

Objectives

To evaluate the clinical outcomes and safety of radiofrequency (RF) ablation for benign non-functioning thyroid nodules over a 4-year follow-up.

Methods

We evaluated 126 benign non-functioning thyroid nodules of 111 patients treated with RF ablation and followed-up more than 3 years. RF ablation was performed using the Cool-Tip RF system and an internally cooled electrode. Nodule volume and cosmetic and symptom scores were evaluated before treatment and during follow-up. Complications and factors related to efficacy were evaluated.

Results

The mean follow-up duration was 49.4?±?13.6 months. Thyroid nodule volume decreased significantly, from 9.8?±?8.5 ml before ablation to 0.9?±?3.3 ml (P?<?0.001) at final evaluation: a mean volume reduction of 93.4?±?11.7 %. The mean cosmetic (P?<?0.001) and symptom scores (P?<?0.001) improved significantly. Factors related to efficacy were initial solidity and volume. The overall recurrence rate was 5.6 % (7/126). The overall complication rate was 3.6 % (4/111).

Conclusions

RF ablation was effective in shrinking benign thyroid nodules and in controlling nodule-related problems over a 4-year follow-up. There were no life-threatening complications or sequelae. Therefore, RF ablation can be used as a non-surgical treatment for patients with benign non-functioning thyroid nodules.

Key Points

? Radiofrequency (RF) ablation provides a non-surgical option for benign non-functioning thyroid nodules ? RF ablation reduced non-functioning thyroid nodular volume by 93.5 % after 49 months ? Initial solidity and volume influenced the efficacy of RF ablation ? Larger thyroid nodules required more treatment sessions to achieve appropriate volume reduction ? Complete treatment of the periphery of the nodule is important in preventing marginal regrowth     

Diagnostic performances of shear wave elastography: which parameter to use in differential diagnosis of solid breast masses?

Objective

To evaluate which shear wave elastography (SWE) parameter proves most accurate in the differential diagnosis of solid breast masses.

Methods

One hundred and fifty-six breast lesions in 139 consecutive women (mean age: 43.54?±?9.94 years, range 21–88 years), who had been scheduled for ultrasound-guided breast biopsy, were included. Conventional ultrasound and SWE were performed in all women before biopsy procedures. Ultrasound BI-RADS final assessment and SWE parameters were recorded. Diagnostic performance of each SWE parameter was calculated and compared with those obtained when applying cut-off values of previously published data. Performance of conventional ultrasound and ultrasound combined with each parameter was also compared.

Results

Of the 156 breast masses, 120 (76.9 %) were benign and 36 (23.1 %) malignant. Maximum stiffness (Emax) with a cut-off of 82.3 kPa had the highest area under the receiver operating characteristics curve (Az) value compared with other SWE parameters, 0.860 (sensitivity 88.9 %, specificity 77.5 %, accuracy 80.1 %). Az values of conventional ultrasound combined with each SWE parameter showed lower (but not significantly) values than with conventional ultrasound alone.

Conclusions

Maximum stiffness (82.3 kPa) provided the best diagnostic performance. However the overall diagnostic performance of ultrasound plus SWE was not significantly better than that of conventional ultrasound alone.

Key Points

? SWE offers new information over and above conventional breast ultrasound ? Various SWE parameters were explored regarding distinction between benign and malignant lesions ? An elasticity of 82.3 kPa appears optimal in differentiating solid breast masses ? However, ultrasound plus SWE was not significantly better than conventional ultrasound alone     

Optimisation of volume-doubling time cutoff for fast-growing lung nodules in CT lung cancer screening reduces false-positive referrals

Objective

To retrospectively investigate whether optimisation of volume-doubling time (VDT) cutoff for fast-growing nodules in lung cancer screening can reduce false-positive referrals.

Methods

Screening participants of the NELSON study underwent low-dose CT. For indeterminate nodules (volume 50–500 mm³), follow-up CT was performed 3 months after baseline. A negative baseline screen resulted in a regular second-round examination 1 year later. Subjects referred to a pulmonologist because of a fast-growing (VDT <400 days) solid nodule in the baseline or regular second round were included in this study. Histology was the reference for diagnosis, or stability on subsequent CTs, confirming benignity. Mean follow-up of non-resected nodules was 4.4 years. Optimisation of the false-positive rate was evaluated at maintained sensitivity for lung cancer diagnosis with VDT <400 days as reference.

Results

Sixty-eight fast-growing nodules were included; 40 % were malignant. The optimal VDT cutoff for the 3-month follow-up CT after baseline was 232 days. This cutoff reduced false-positive referrals by 33 % (20 versus 30). For the regular second round, VDTs varied more among malignant nodules, precluding lowering of the VDT cutoff of 400 days.

Conclusion

All malignant fast-growing lung nodules referred after the 3-month follow-up CT in the baseline lung cancer screening round had VDT ≤232 days. Lowering the VDT cutoff may reduce false-positive referrals.

Key Points

? Lung nodules are common in CT lung cancer screening, most being benign ? Short-term follow-up CT can identify fast-growing intermediate-size lung nodules ? Most fast-growing nodules on short-term follow-up CT still prove to be benign ? A new volume-doubling time (VDT) cut-off is proposed for lung screening ? The optimised VDT cutoff may decrease false-positive case referrals for lung cancer     

Percutaneous transthoracic needle biopsy of small (≤1 cm) lung nodules under C-arm cone-beam CT virtual navigation guidance

Objectives

To describe our initial experience with percutaneous transthoracic needle biopsy (PCNB) of small (≤1 cm) lung nodules using a cone-beam computed tomography (CBCT) virtual navigation guidance system in 105 consecutive patients.

Methods

One hundred and five consecutive patients (55 male, 50 female; mean age, 62 years) with 107 small (≤1 cm) lung nodules (mean size, 0.85 cm?±?0.14) underwent PCNBs under CBCT virtual-navigation guidance system and constituted our study population. Procedural details—including radiation dose, sensitivity, specificity, diagnostic accuracy and complication rates of CBCT virtual navigation guided PCNBs—were described.

Results

The mean number of pleural passages with the coaxial needle, biopsies, CT acquisitions, total procedure time, coaxial introducer dwelling time, and estimated radiation exposure during PCNBs were 1.03?±?0.21, 3.1?±?0.7, 3.4?±?1.3, 10.5 min?±?3.2 and 7.2 min?±?2.5, and 5.72 mSv?±?4.19, respectively. Sixty nodules (56.1 %) were diagnosed as malignant, 38 (35.5 %) as benign and nine (8.4 %) as indeterminate. The sensitivity, specificity, and diagnostic accuracy of CBCT virtual-navigation-guided PCNB for small (≤1 cm) nodules were 96.7 % (58/60), 100 % (38/38) and 98.0 % (96/98), respectively. Complications occurred in 13 (12.1 %) cases; pneumothorax in seven (6.5 %) and haemoptysis in six (5.6 %).

Conclusion

CBCT virtual-navigation-guided PCNB is a highly accurate and safe diagnostic method for small (≤1 cm) nodules.

Key Points

? CBCT virtual-navigation guidance offers new biopsy options for lung nodules ? CBCT virtual-navigation-guided PCNB is highly accurate for small (≤1 cm) nodules ? CBCT virtual-navigation-guided PCNB for small (≤1 cm) nodules is safe ? Procedure time and radiation exposure of CBCT virtual-navigation-guided PCNB is reasonable     

Diagnostic performances of shear-wave elastography for identification of malignant breast lesions: a meta-analysis

Purpose

To examine the performance of shear-wave elastography (SWE) for the differentiation of benign and malignant breast lesions using a meta-analysis.

Materials and methods

PubMed, Embase and the Cochrane library were searched for studies published up to January 2014. The references of retrieved relevant articles were reviewed to identify potential publications. Random-effect meta-analysis was conducted to assess the overall sensitivity and specificity of SWE in the differentiation of breast lesions.

Results

A total of 11 articles, including 2424 patients, were included in the present meta-analysis. The summarized sensitivity and specificity of the shear wave elastography performance based on maximum elasticity were 0.93 (95 % CI 0.91–0.95) and 0.81 (95 % CI 0.78–0.83), respectively. For the mean elasticity, the summarized sensitivity and specificity were 0.94 (95 % CI 0.92–0.96) and 0.71 (95 % CI 0.69–0.74), respectively. The summarized sensitivity and specificity were 0.77 (95 % CI 0.70–0.83) and 0.88 (95 % CI 0.84–0.91) for the SD of elasticity.

Conclusion

SWE has a high sensitivity and specificity in the differentiation of benign and malignant breast lesions. More large and prospective studies are warranted to further examine the performance of SWE.     

Differentiation of benign from malignant solid breast masses: comparison of two-dimensional and three-dimensional shear-wave elastography

Objectives

To prospectively compare the diagnostic performances of two-dimensional (2D) and three-dimensional (3D) shear-wave elastography (SWE) for differentiating benign from malignant breast masses.

Methods

B-mode ultrasound and SWE were performed for 134 consecutive women with 144 breast masses before biopsy. Quantitative elasticity values (maximum and mean elasticity in the stiffest portion of mass, E_max and E_mean; lesion-to-fat elasticity ratio, E_rat) were measured with both 2D and 3D SWE. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity of B-mode, 2D, 3D SWE and combined data of B-mode and SWE were compared.

Results

Sixty-seven of the 144 breast masses (47 %) were malignant. Overall, higher elasticity values of 3D SWE than 2D SWE were noted for both benign and malignant masses. The AUC for 2D and 3D SWE were not significantly different: E_mean, 0.938 vs 0.928; E_max, 0.939 vs 0.930; E_rat, 0.907 vs 0.871. Either 2D or 3D SWE significantly improved the specificity of B-mode ultrasound from 29.9 % (23 of 77) up to 71.4 % (55 of 77) and 63.6 % (49 of 77) without a significant change in sensitivity.

Conclusion

Two-dimensional and 3D SWE performed equally in distinguishing benign from malignant masses and both techniques improved the specificity of B-mode ultrasound.

Key Points

? Shear-wave elastography (SWE) is increasingly used during ultrasound of the breast ? 2D and 3D SWE performed equally in distinguishing benign from malignant masses ? Either SWE method, combined with B-mode, outperformed B-mode ultrasound alone ? Quantitative elasticity was greater for 3D than 2D SWE for all masses     

Shear-wave elastography in the diagnosis of solid breast masses: what leads to false-negative or false-positive results?

Objective

To investigate the factors that have an effect on false-positive or false-negative shear-wave elastography (SWE) results in solid breast masses.

Methods

From June to December 2012, 222 breast lesions of 199 consecutive women (mean age: 45.3?±?10.1 years; range, 21 to 88 years) who had been scheduled for biopsy or surgical excision were included. Greyscale ultrasound and SWE were performed in all women before biopsy. Final ultrasound assessments and SWE parameters (pattern classification and maximum elasticity) were recorded and compared with histopathology results. Patient and lesion factors in the ‘true’ and ‘false’ groups were compared.

Results

Of the 222 masses, 175 (78.8 %) were benign, and 47 (21.2 %) were malignant. False-positive rates of benign masses were significantly higher than false-negative rates of malignancy in SWE patterns, 36.6 % to 6.4 % (P?<?0.001). Among both benign and malignant masses, factors showing significance among false SWE features were lesion size, breast thickness and lesion depth (all P?<?0.05). All 47 malignant breast masses had SWE images of good quality.

Conclusions

False SWE features were more significantly seen in benign masses. Lesion size, breast thickness and lesion depth have significance in producing false results, and this needs consideration in SWE image acquisition.

Key Points

? Shear-wave elastography (SWE) is widely used during breast imaging ? At SWE, false-positive rates were significantly higher than false-negative rates ? Larger size, breast thickness, depth and fair quality influences false-positive SWE features ? Smaller size, larger breast thickness and depth influences false-negative SWE features     

Q-Elastosonography of Solid Thyroid Nodules: Assessment of Diagnostic Efficacy and Interobserver Variability in a Large Patient Cohort

Objective

Evaluation of the diagnostic efficacy and interobserver agreement of Q-elastography in the differentiation of benign from malignant thyroid nodules.

Methods

A total of 344 thyroid nodules in 288 patients were examined with grey-scale and colour Doppler ultrasound (CDUS) and Q-elastography by two independent operators. Nodules with hypoechogenicity, poorly defined margins, microcalcifications, and intralesional vascularity were classified as suspicious. Diagnostic performances of CDUS features and Q-elastography for predicting thyroid malignancy were estimated using ROC analysis. Cytology or histopathology was the reference standard. Interobserver agreement in the evaluation of CDUS and Q-elastography was assessed using Cohen's k-statistic.

Results

Q-elastography showed excellent diagnostic performance for the prediction of thyroid malignancy, with sensitivity of 93 % and specificity of 92 % for operator 1 (best cutoff at 2.02), and sensitivity of 84 % and specificity of 79 % for operator 2 (best cutoff at 1.86). Performance of Q-elastography was superior to that of CDUS. Reproducibility of the findings was excellent for both Q-elastography and CDUS features as assessed with Cohen's k, which was highest for strain ratio measurements (0.95) and lowest for the echogenicity score (0.83).

Conclusions

Q-elastography showed excellent performance. It is a valid and reproducible diagnostic method as well as a promising tool for identifying suspicious solid thyroid nodules needing cytological assessment and surgery.

Key Points

? Elastography is an additional tool for optimal characterisation of malignant thyroid nodules. ? The use of semiquantitative elastographic evaluation increases the diagnostic performance, ? The interobserver agreement of quantitative elastography can be considered to be good.     

Persistent pulmonary subsolid nodules: model-based iterative reconstruction for nodule classification and measurement variability on low-dose CT

Objectives

To compare the pulmonary subsolid nodule (SSN) classification agreement and measurement variability between filtered back projection (FBP) and model-based iterative reconstruction (MBIR).

Methods

Low-dose CTs were reconstructed using FBP and MBIR for 47 patients with 47 SSNs. Two readers independently classified SSNs into pure or part-solid ground-glass nodules, and measured the size of the whole nodule and solid portion twice on both reconstruction algorithms. Nodule classification agreement was analyzed using Cohen’s kappa and compared between reconstruction algorithms using McNemar’s test. Measurement variability was investigated using Bland–Altman analysis and compared with the paired t-test.

Results

Cohen’s kappa for inter-reader SSN classification agreement was 0.541–0.662 on FBP and 0.778–0.866 on MBIR. Between the two readers, nodule classification was consistent in 79.8 % (75/94) with FBP and 91.5 % (86/94) with MBIR (p?=?0.027). Inter-reader measurement variability range was -5.0–2.1 mm on FBP and -3.3–1.8 mm on MBIR for whole nodule size, and was -6.5–0.9 mm on FBP and -5.5–1.5 mm on MBIR for solid portion size. Inter-reader measurement differences were significantly smaller on MBIR (p?=?0.027, whole nodule; p?=?0.011, solid portion).

Conclusions

MBIR significantly improved SSN classification agreement and reduced measurement variability of both whole nodules and solid portions between readers.

Key Points

? Low-dose CT using MBIR algorithm improves reproducibility in the classification of SSNs. ? MBIR would enable more confident clinical planning according to the SSN type. ? Reduced measurement variability on MBIR allows earlier detection of potentially malignant nodules.     

Diagnostic value of commercially available shear-wave elastography for breast cancers: integration into BI-RADS classification with subcategories of category 4

Objectives

To evaluate the diagnostic performance of shear-wave elastography (SWE) for breast cancer and to determine whether the integration of SWE into BI-RADS with subcategories of category 4 improves the diagnostic performance.

Methods

A total of 389 breast masses (malignant 120, benign 269) in 324 women who underwent SWE before ultrasound-guided core biopsy or surgery were included. The qualitative SWE feature was assessed using a four-colour overlay pattern. Quantitative elasticity values including the lesion-to-fat elasticity ratio (E_ratio) were measured. Diagnostic performance of B-mode ultrasound, SWE, or their combined studies was compared using the area under the ROC curve (AUC).

Results

AUC of E_ratio (0.952) was the highest among elasticity values (mean, maximum, and minimum elasticity, 0.949, 0.939, and 0.928; P?=?0.04) and AUC of colour pattern was 0.947. AUC of combined studies was significantly higher than for a single study (P?<?0.0001). When adding SWE to category 4 lesions, lesions were dichotomised according to % of malignancy: 2.1 % vs. 43.2 % (category 4a) and 0 % vs. 100 % (category 4b) for E_ratio and 2.4 % vs. 25.8 % (category 4a) for colour pattern (P?<?0.05).

Conclusions

Shear-wave elastography showed a good diagnostic performance. Adding SWE features to BI-RADS improved the diagnostic performance and may be helpful to stratify category 4 lesions.

Key points

? Quantitative and qualitative shear-wave elastography provides further diagnostic information during breast ultrasound. ? The elasticity ratio (E _ratio ) showed the best diagnostic performance in SWE. ? E _ratio and four-colour overlay pattern significantly differed between benign and malignant lesions. ? SWE features allowed further stratification of BI-RADS category 4 lesions.     

Evaluation of shearwave elastography for the characterisation of focal liver lesions on ultrasound

Objectives

To determine the elasticity characteristics of focal liver lesions (FLLs) by shearwave elastography (SWE).

Methods

We used SWE in 108 patients with 161 FLLs and in the adjacent liver for quantitative and qualitative FLLs stiffness assessment. The Mann–Whitney test was used to assess the difference between the groups of lesions where a P value less than 0.05 was considered significant.

Results

SWE acquisitions failed in 22 nodules (14 %) in 13 patients. For the 139 lesions successfully evaluated, SWE values were (in kPa), for the 3 focal fatty sparings (FFS) 6.6?±?0.3, for the 10 adenomas 9.4?±?4.3, for the 22 haemangiomas 13.8?±??5.5, for the 16 focal nodular hyperplasias (FNHs) 33?±??14.7, for the 2 scars 53.7?±?4.7, for the 26 HCCs 14.86?±?10, for the 53 metastasis 28.8?±?16, and for the 7 cholangiocarcinomas 56.9?±?25.6. FNHs had significant differences in stiffness compared with adenomas (P?=?0.0002). Fifty percent of the FNHs had a radial pattern of elevated elasticity. A significant difference was also found between HCCs and cholangiocarcinomas elasticity (P?=?0.0004).

Conclusions

SWE could be useful in differentiating FNHs and adenomas, or HCCs and cholangiocarcinomas by ultrasound.

Key Points

? Elastography is becoming quite widely used as an adjunct to conventional ultrasound ? Shearwave elastography (SWE) could help differentiate adenomas from fibrous nodular hyperplasia ? SWE could also be helpful in distinguishing between hepatocellular carcinomas and cholangiocarcinomas ? SWE could improve the identify hepatocellular carcinomas in cirrhotic livers     

Potential role of shear-wave ultrasound elastography for the differential diagnosis of breast non-mass lesions: preliminary report

Objectives

To report our preliminary experience with shear-wave elastography (SWE) for non-mass lesions (NMLs) in the breast and suggest a potential ancillary role of SWE for BI-RADS Category 4a NMLs in reducing the number of unnecessary benign biopsies.

Methods

A total of 310 breast lesions in 286 consecutive women who had been scheduled for US-guided automated gun biopsy or vacuum-assisted biopsy between June and December 2012 were initially included in this study. Finally, 33 women with 34 breast lesions classified as NMLs constituted our study population. Diagnostic performances of each quantitative SWE parameter were calculated. Histological diagnosis was used as a reference standard.

Results

Among the 34 breast NMLs, 22 (65 %) were benign and 12 (35 %) were malignant. E_mean value with cut-off set at 41.6 kPa had the highest Az value 0.788 (95 % CI, 0.625–0.951), showing sensitivity of 83.3 % and specificity of 68.2 %. By applying an E_mean value of 41.6 kPa or less as a criterion for downgrading soft BI-RADS category 4a NMLs to category 3 NMLs, 15 unnecessary biopsies could have been eliminated from the 19 BI-RADS category 4a lesions (79 %).

Conclusions

SWE features could increase positive predictive values and reduce unnecessary benign biopsies of category 4a NMLs.

Key points

? Ultrasound elastography is increasingly used to assess the stiffness of breast lesions ? Shear-wave elastography provides useful information about non-mass breast lesions ? Shear-wave elastography may render some biopsies of non-mass breast lesions unnecessary     

Core needle biopsy can minimise the non-diagnostic results and need for diagnostic surgery in patients with calcified thyroid nodules

Purpose

To evaluate the role of core needle biopsy (CNB) for calcified thyroid nodules.

Methods

Between October 2008 and July 2011, 264 patients underwent ultrasound-guided CNB for 272 calcified thyroid nodules at our institution. We retrospectively evaluated the incidence of technical failure, non-diagnostic readings, and the diagnostic performance of CNB, and analysed the relationship between the types of calcification and the CNB results. Finally, the incidence of diagnostic surgery was calculated.

Results

The incidence of technical failure was 1.1 % (3/275) and that of non-diagnostic results was 0.7 % (2/272). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CNB were 94.7 %, 89.5 %, 100 %, 100 %, and 90.2 %, respectively. There were no significant differences according to the calcification subtype for either the non-diagnostic results or the incidence of technical failure (P?>?0.99 and P?>?0.99). CNB could prevent diagnostic surgery for 92.9 % (13/14) of the patients who showed more than two non-diagnostic results in previous FNA.

Conclusions

CNB can minimise the non-diagnostic results as well as diagnostic surgery in patients with calcified thyroid nodules. Therefore, CNB may be used as a first-line diagnostic tool for calcified thyroid nodules rather than FNA.

Key points

? CNB results show the low incidence of technical failure (1.1 %, 3/275). ? CNB results show the low non-diagnostic rate (0.7 %, 2/272). ? There were no significant differences according to the calcification subtype. ? CNB can prevent unnecessary diagnostic surgery in 92.9 % (13/14).     

Visually assessed colour overlay features in shear-wave elastography for breast masses: quantification and diagnostic performance

Objectives

To determine whether colour overlay features can be quantified by the standard deviation (SD) of the elasticity measured in shear-wave elastography (SWE) and to evaluate the diagnostic performance for breast masses.

Methods

One hundred thirty-three breast lesions in 119 consecutive women who underwent SWE before US-guided core needle biopsy or surgical excision were analysed. SWE colour overlay features were assessed using two different colour overlay pattern classifications. Quantitative SD of the elasticity value was measured with the region of interest including the whole breast lesion.

Results

For the four-colour overlay pattern, the area under the ROC curve (Az) was 0.947; with a cutoff point between pattern 2 and 3, sensitivity and specificity were 94.4 % and 81.4 %. According to the homogeneity of the elasticity, the Az was 0.887; with a cutoff point between reasonably homogeneous and heterogeneous, sensitivity and specificity were 86.1 % and 82.5 %. For the SD of the elasticity, the Az was 0.944; with a cutoff point of 12.1, sensitivity and specificity were 88.9 % and 89.7 %. The colour overlay features showed significant correlations with the quantitative SD of the elasticity (P?<?0.001).

Conclusion

The colour overlay features and the SD of the elasticity in SWE showed excellent diagnostic performance and showed good correlations between them.

Key Points

? Shear-wave elastography provides both qualitative and quantitative information of breast mass stiffness ? Qualitative colour overlay features can be quantified to assess breast mass heterogeneity ? Qualitative and quantitative elasticity features can help differentiate benign and malignant lesions     

Cystic versus predominantly cystic thyroid nodules: efficacy of ethanol ablation and analysis of related factors

Objectives

To compare the efficacy of ethanol ablation (EA) of cystic and predominantly cystic thyroid nodules, and to evaluate factors affecting efficacy.

Methods

From October 2008 to December 2010, a total of 217 thyroid nodules were treated with EA. Nodule volumes, symptoms and cosmetic scores were evaluated before and after EA. EA efficacy in treating cystic and predominantly cystic nodules was compared; and factors related to EA efficacy in each type, including initial volume, solid component, vascularity, fluid nature, ethanol retention time and number of EA sessions, were evaluated.

Results

Mean nodule volume decreased from 15.7?±?18.1 ml to 3.0?±?7.9 ml (mean volume reduction, 85.2?±?16.1%) and the therapeutic success rate was 90.3% at last follow-up. EA was significantly more effective in cystic than predominantly cystic nodules. Independent predictors of EA efficacy for all nodules included initial volume, solid component and vascularity. Initial volume and vascularity were independent predictors of EA efficacy in predominantly cystic nodules, but no factor was independently related to efficacy in cystic nodules.

Conclusions

EA is effective in both cystic and predominantly cystic nodules, especially the former. EA is less effective in large or vascular predominantly cystic nodules, but is effective in cystic nodules regardless of related factors.

Key Points

? Ethanol ablation under ultrasound guidance is increasingly used for cystic thyroid nodules. ? EA seems effective for cystic and predominantly cystic nodules, especially cystic nodules. ? The effectiveness of EA was reduced in large or vascular predominantly cystic nodules.     

Prospective evaluation of solitary thyroid nodule on 18F-FDG PET/CT and high-resolution ultrasonography

Purpose

The utility of 18F-FDG PET/CT in the assessment of thyroid nodules is unclear as there are several conflicting reports on the usefulness of SUV as an indicator to distinguish benign from malignant thyroid lesions. This study incorporated an additional parameter, namely dual time point imaging, to determine the diagnostic accuracy of PET/CT imaging. The performance of 18F-FDG PET/CT was compared to that of high-resolution ultrasound which is routinely used for the evaluation of thyroid nodules.

Methods

Two hundred patients with incidentally detected solitary thyroid nodules were included in the study. Each patient underwent ultrasound and PET/CT evaluation within 7 days of each other, reported by an experienced radiologist and nuclear medicine specialist, respectively, in a blinded manner. The PET/CT criteria employed were maximum SUV (SUV_max) at 60 min and change in SUV_max at delayed (120 min) imaging. Final diagnosis was based on pathological evaluation and follow-up.

Results

Of the 200 patients, 26 had malignant and 174 had benign nodules. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of ultrasound were 80.8, 81.6, 39.6, 96.6 and 81.5%, respectively. Using SUV_max at 60 min as the diagnostic criterion, the above indices were 80.8, 84.5, 43.8, 96.7 and 84%, respectively, for PET/CT. The SUV_max of malignant thyroid lesions was significantly higher than benign lesions (16.2 ± 10.6 vs. 4.5 ± 3.1, respectively; p = 0.0001). Incorporation of percentage change in SUV_max at delayed imaging as the diagnostic criterion yielded a slightly improved sensitivity, specificity, PPV, NPV and accuracy of 84.6, 85.6, 46.8, 97.4 and 85.5%, respectively. There was a significant difference in percentage change in SUV_max between malignant and benign thyroid lesions (14.9 ± 11.4 vs. ?1.6 ± 13.7, respectively; p = 0.0001). However, there was no statistically significant difference (95% confidence interval) between the diagnostic performance of PET/CT and ultrasound.

Conclusions

Routine use of 18F-FDG PET/CT with SUV_max at 60 min as the sole diagnostic criterion does not appear to have a significant advantage over high-resolution ultrasound in the evaluation of thyroid nodules. Incorporation of dual time point imaging enhances image interpretation, and yields a higher diagnostic performance, yet it is not statistically significant. Bearing in mind the cost, limited availability and radiation exposure, routine use of 18F-FDG PET/CT for distinguishing benign from malignant thyroid nodules cannot be recommended.