Superb Microvascular Imaging Compared with Contrast-Enhanced Ultrasound for Assessing Laser Ablation Treatment of Benign Thyroid Nodules

Abstract

Purpose To compare superb microvascular imaging (SMI) with contrast-enhanced ultrasonography (CEUS) for evaluating the ablation of benign thyroid nodules. Methods 225 Patients with 256 benign thyroid nodules underwent conventional ultrasound, color Doppler flow imaging (CDFI), CEUS, and SMI before and after laser ablation. They were routinely followed up at 1, 3, 6, and 12 months. The volume and volume reduction rate of the ablated nodules was calculated. Results On SMI, the complete ablated nodules had no microvascular perfusion, while the incompletely ablated nodules had microvascular perfusion at the edge of the nodule. The percentages of the detected incompletely ablated nodules of SMI (37/256, 14.45%) and CEUS (41/256, 16.02%) were comparable, and both were significantly higher than CDFI (P< 0.001). CEUS was used as the criterion to determine whether the nodules were completely ablated. The sensitivity, specificity, and accuracy of SMI for detecting incompletely ablated nodules were 90.2, 98.2, and 100%, respectively. The volume of ablated nodules, as measured on ultrasound, was greater than that on CEUS or SMI (both P< 0.001), while CEUS and SMI were similar. The average volume reduction rate of nodules at 1, 3, 6, and 12 months was 40.25, 54.98, 76.83, and 95.43%, respectively. Conclusion SMI sensitively detected the capillaries within residual thyroid nodules after laser ablation. The lesion size and detection rate of incompletely ablated nodules via SMI was consistent with that of CEUS. SMI may replace CEUS in certain cases for monitoring the curative effect of laser ablation for benign thyroid nodules.

Evaluation of parenchymal vascularity of the thyroid gland with vascularization index by color superb microvascular imaging in patients with Graves’ disease

“…To the best of our knowledge, the present study is the first analysis which utilized the VI measured by cSMI in the assessment of thyroid vascularization in adult patients with diffuse thyroid disease. Other studies applying SMI to the thyroid gland in adults focused on thyroid nodules and malignancies (6,7,(23)(24)(25)(26)(27)(28) .…”

Clinical applications of Doppler ultrasonography for thyroid disease: consensus statement by the Korean Society of Thyroid Radiology

“…To overcome these disadvantages of CDUS, some authors have suggested that CEUS can be used as an ancillary diagnostic tool for detecting under-ablated portions after an RFA procedure [99][100][101]. Doppler US is also a primary imaging modality during follow-up after other ablation procedures, including laser ablation [102][103][104], microwave ablation [105][106][107], and highintensity focused US ablation [108,109]. Most studies have used a color Doppler technique [102,[104][105][106][107]109], while some have used PDUS [108], SMI [103], or CEUS [103].…”

“…Some researchers have suggested that the ablation zone is clearer with CEUS than with CDUS [110,111]. Furthermore, a recent study has suggested that the accuracy of SMI for the detection of undertreated areas after laser ablation of thyroid nodules is similar to that of CEUS [103].…”

“…Doppler US is also a primary imaging modality during follow-up after other ablation procedures, including laser ablation [ 102 - 104 ], microwave ablation [ 105 - 107 ], and high-intensity focused US ablation [ 108 , 109 ]. Most studies have used a color Doppler technique [ 102 , 104 - 107 , 109 ], while some have used PDUS [ 108 ], SMI [ 103 ], or CEUS [ 103 ]. Some researchers have suggested that the ablation zone is clearer with CEUS than with CDUS [ 110 , 111 ].…”

Evaluation of benign parotid gland tumors with superb microvascular imaging and shear wave elastography

“…To our knowledge, only a few reports can be found in the literature which evaluate the role of SMI in parotid gland tumors. Previous studies with SMI have addressed thyroid gland, lymph nodes, testes, and breast lesions (10,13,(25)(26)(27)(28)(29) .…”