Role of Sonazoid-based contrast-enhanced ultrasonography in the microwave ablation of primary hyperparathyroidism

Figures & data

Figure 1. Diagrammatic representation of two different needle-tract routes (trans-thyroidal and direct approach) for percutaneous ablation. CCA: common carotid artery; IJV: internal jugular vein.

Figure 2. Flow chart of patients included in the study. sHPT: secondary hyperparathyroidism; MIBI: 99 m Tc-sestamibi; pHPT: primary hyperparathyroidism; MWA: microwave ablation; and PTX: parathyroidectomy.

Table 1. Baseline clinical and treatment characteristics of patients with pHPT (n = 40).

Characteristic	Data
Mean age (years)	54.9 ± 11.8
Sex (male/female)	12/28
Clinical manifestations
Nephrolithiasis (n)	6
Osteoporosis (n)	5
Asymptomatic (n)	29
Blood biochemistry
iPTH (pg/ml)	178.5 (134.5–229.3)
Calcium (mmol/l)	2.68 ± 0.24
25-hydroxyvitamin D (ng/ml)	23 (13.3–40)
No. of nodules	44
Maximum diameter (cm)	1.09 ± 0.28
Volume (cm^3)	0.36 ± 0.19
Nodule location
Normal location	40
Ectopic location	4
Within thyroid	2
Within carotid sheath	1
Upper mediastinum	1
Needle-tract routes
Trans-thyroidal approach	37
Direct approach	7
Microwave ablation
Ablation time per nodule (s)	218.4 ± 37.9
Ablation power per nodule (W)	41.5 (40–45)
Volume of hydrodissection solution (mL)	30.3 ± 6.0

pHPT: primary hyperparathyroidism.

Figure 3. CEUS displaying incomplete ablation in a 46-year-old woman with pHPT. (A) CEUS images immediately after MWA: non-enhancement area covers the pHPT nodule (arrows). (B) Color Doppler images 1 day after MWA: signs of punctate blood flow signals of the margin of the ablation zone (arrows). (C) CEUS images 1 day after MWA: the arterial phase demonstrates an annular enhancement area (arrows) around the ablation zone. (D) US images 1 year after ablation: the VRR of the ablation zone (arrows) is 83.6% ablation zone (arrows). CEUS: contrasted-enhanced ultrasound; pHPT: primary hyperparathyroidism; MWA: microwave ablation; VRR: volume reduction rate; US: ultrasound.

Table 2. Changes in US features and serum biochemical data before MWA and at each follow-up.

Follow-up time (number)	PTH (pg/ml)	Calcium (mmol/l)	Maximum diameter (cm)	Volume (cm^3)	VRR (%)
Pre-MWA	178.5 (134.5–229.3)	2.68 ± 0.24	1.09 ± 0.28	0.36 ± 0.19
Post-MWA
1 D (n = 38)	45.5 (33.3–57.5)*	2.41 ± 0.24*	–	–	–
7 D (n = 38)	75 (50.3–88.8)*	2.39 ± 0.15*	–	–	–
1 M (n = 38)	72 (64–97)*	2.35 ± 0.09*	–	–	–
6 M (n = 38)	47 (39–52)*	2.29 ± 0.07*	0.94 ± 0.22*	0.25 ± 0.11*	44.2 (21.4–63.9)
12M (n = 30)	47 (41–56.7)*	2.31 ± 0.07*	0.77 ± 0.17*	0.15 ± 0.07*	81.2 (53.9–91.4)

Data are presented as mean ± standard deviation. The numbers in parentheses represent ranges. —: not measured. Normal ranges: serum PTH, 15–65 pg/mL; serum calcium, 2.11–2.52 mmol/L. D: day; M: month; VRR: volume reduction rate; MWA: microwave ablation. ^∗ p < 0.05, versus before MWA.

Table 3. Complications and side effects following MWA.

Complications	N (%)	Treatment	Time to recovery (days)
Minor
Hoarseness	6 (15)	Recovered spontaneously	30–100
Hypocalcemia	4 (10)	Calcium supplementation	2–15
Hypoparathyroidism	1 (2.5)	None	7
Side effect
Pain	18 (45)	All patients were well tolerated	0
Neck swelling	40 (100)	None	0
Cough	2 (5)	Symptomatic treatment	2–3

MWA: microwave ablation.

Figure 4. CEUS displaying hidden nodule during hydrodissection in a 55-year-old woman with pHPT. (A) Routine US display a hypoechoic pHPT nodule with maximum diameter of 0.5 cm; (B) Preoperative nodule FNA biopsy indicates a parathyroid adenoma with the formation of microfollicles (H&E stain, ×200). (C) During hydrodissection, nodular changes in the surrounding tissues and the pHPT nodule are hypoechoic (arrow). (D) The injection of contrast agents display the uniform enhanced parathyroid nodule (arrows). CEUS: contrasted-enhanced ultrasound; pHPT: primary hyperparathyroidism; FNA: fine-needle aspiration.