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A Risk Model for Predicting Central Lymph Node Metastasis of Papillary Thyroid Microcarcinoma Including Conventional Ultrasound and Acoustic Radiation Force Impulse Elastography

View Article: PubMed Central - PubMed

ABSTRACT

The aim of this prospective study was to propose a new rating system using a risk model including conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography for predicting central lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC).

A total of 252 patients with PTMCs were enrolled, who were preoperatively evaluated by US and ARFI elastography including virtual touch tissue imaging (VTI) and virtual touch tissue quantification (VTQ). Risk factors of independent variables for central LNM were analyzed by univariate and multivariate analyses. A multivariate analysis was performed to create a predicting model and rating system.

Of the 252 patients, 72 (28.6%) had central LNMs. Multivariate analysis revealed that rare internal flow (odds ratio [OR]: 4.454), multiple suspicious foci on US (OR: 5.136), capsule involvement (OR: 20.632), and VTI area ratio (VAR) > 1 (OR: 5.621) were independent risk factors for central LNM. The final predicting model was obtained and the risk score (RS) was defined as 1.5 × (if rare internal flow) + 1.6 × (if multiple suspicious foci on US) + 1.7 × (if VAR > 1) + 3.0 × (if capsule involvement). The rating system was divided into 5 stages. Stage I, <1.5; Stage II, 1.5 to 3.0; Stage III, 3.1 to 4.7; Stage IV, 4.8 to 6.3; and Stage V, 6.4 to 7.8. The risk rates of central LNM were 3.4% (2/59) in Stage I, 13.3% (13/98) in Stage II, 54.2% (39/72) in Stage III, 72.2% (13/18) in Stage IV, and 100% (5/5) in Stage V (P < 0.001).

The results indicated that rare internal flow, multiple suspicious foci, capsule involvement on US, and VAR > 1 on ARFI elastography are the risk factors for predicting central LNM. The risk model developed in the study clearly predicts the risk of central LNM in patients with PTMC and thus has a potential to avoid unnecessary central compartment node dissection.

No MeSH data available.


Related in: MedlinePlus

Conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography findings of central lymph node metastasis (LNM) in a 36-year-old female patient with right papillary thyroid microcarcinoma (PTMC). (A) A longitudinal US image shows that a 10-mm PTMC invades thyroid capsule with a loss of echogenicity (arrow). (B) Rare internal flow is found on color Doppler flow image of the PTMC. (C) A virtual touch tissue imaging (VTI) image shows that the VTI area ratio (VAR) (linered/lineyellow) is larger than 1. (D) SWV of 2.24 m/s is displayed on virtual touch tissue quantification (VTQ) image. SWV = shear wave velocity.
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Figure 1: Conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography findings of central lymph node metastasis (LNM) in a 36-year-old female patient with right papillary thyroid microcarcinoma (PTMC). (A) A longitudinal US image shows that a 10-mm PTMC invades thyroid capsule with a loss of echogenicity (arrow). (B) Rare internal flow is found on color Doppler flow image of the PTMC. (C) A virtual touch tissue imaging (VTI) image shows that the VTI area ratio (VAR) (linered/lineyellow) is larger than 1. (D) SWV of 2.24 m/s is displayed on virtual touch tissue quantification (VTQ) image. SWV = shear wave velocity.

Mentions: Multivariate logistic regression analysis entering all independent variables in this study was performed and determined that the predictors such as multiple suspicious foci on US (OR: 5.136, P < 0.001), rare internal flow (OR: 4.454, P = 0.001), capsule involvement (OR: 20.632, P < 0.001), and VAR > 1 (OR: 5.621, P < 0.001) were independent risk factors for predicting central compartment LNM (Figure 1). Age (OR: 0.942, P < 0.001) and taller than wide shape (OR: 0.314, P = 0.006) were significantly associated with low risk for central compartment LNM (Table 3).


A Risk Model for Predicting Central Lymph Node Metastasis of Papillary Thyroid Microcarcinoma Including Conventional Ultrasound and Acoustic Radiation Force Impulse Elastography
Conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography findings of central lymph node metastasis (LNM) in a 36-year-old female patient with right papillary thyroid microcarcinoma (PTMC). (A) A longitudinal US image shows that a 10-mm PTMC invades thyroid capsule with a loss of echogenicity (arrow). (B) Rare internal flow is found on color Doppler flow image of the PTMC. (C) A virtual touch tissue imaging (VTI) image shows that the VTI area ratio (VAR) (linered/lineyellow) is larger than 1. (D) SWV of 2.24 m/s is displayed on virtual touch tissue quantification (VTQ) image. SWV = shear wave velocity.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4998281&req=5

Figure 1: Conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography findings of central lymph node metastasis (LNM) in a 36-year-old female patient with right papillary thyroid microcarcinoma (PTMC). (A) A longitudinal US image shows that a 10-mm PTMC invades thyroid capsule with a loss of echogenicity (arrow). (B) Rare internal flow is found on color Doppler flow image of the PTMC. (C) A virtual touch tissue imaging (VTI) image shows that the VTI area ratio (VAR) (linered/lineyellow) is larger than 1. (D) SWV of 2.24 m/s is displayed on virtual touch tissue quantification (VTQ) image. SWV = shear wave velocity.
Mentions: Multivariate logistic regression analysis entering all independent variables in this study was performed and determined that the predictors such as multiple suspicious foci on US (OR: 5.136, P < 0.001), rare internal flow (OR: 4.454, P = 0.001), capsule involvement (OR: 20.632, P < 0.001), and VAR > 1 (OR: 5.621, P < 0.001) were independent risk factors for predicting central compartment LNM (Figure 1). Age (OR: 0.942, P < 0.001) and taller than wide shape (OR: 0.314, P = 0.006) were significantly associated with low risk for central compartment LNM (Table 3).

View Article: PubMed Central - PubMed

ABSTRACT

The aim of this prospective study was to propose a new rating system using a risk model including conventional ultrasound (US) and acoustic radiation force impulse (ARFI) elastography for predicting central lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC).

A total of 252 patients with PTMCs were enrolled, who were preoperatively evaluated by US and ARFI elastography including virtual touch tissue imaging (VTI) and virtual touch tissue quantification (VTQ). Risk factors of independent variables for central LNM were analyzed by univariate and multivariate analyses. A multivariate analysis was performed to create a predicting model and rating system.

Of the 252 patients, 72 (28.6%) had central LNMs. Multivariate analysis revealed that rare internal flow (odds ratio [OR]: 4.454), multiple suspicious foci on US (OR: 5.136), capsule involvement (OR: 20.632), and VTI area ratio (VAR) &gt; 1 (OR: 5.621) were independent risk factors for central LNM. The final predicting model was obtained and the risk score (RS) was defined as 1.5&#8202;&times;&#8202;(if rare internal flow) + 1.6&#8202;&times;&#8202;(if multiple suspicious foci on US) + 1.7&#8202;&times;&#8202;(if VAR &gt; 1) + 3.0&#8202;&times;&#8202;(if capsule involvement). The rating system was divided into 5 stages. Stage I, &lt;1.5; Stage II, 1.5 to 3.0; Stage III, 3.1 to 4.7; Stage IV, 4.8 to 6.3; and Stage V, 6.4 to 7.8. The risk rates of central LNM were 3.4% (2/59) in Stage I, 13.3% (13/98) in Stage II, 54.2% (39/72) in Stage III, 72.2% (13/18) in Stage IV, and 100% (5/5) in Stage V (P&#8202;&lt;&#8202;0.001).

The results indicated that rare internal flow, multiple suspicious foci, capsule involvement on US, and VAR &gt; 1 on ARFI elastography are the risk factors for predicting central LNM. The risk model developed in the study clearly predicts the risk of central LNM in patients with PTMC and thus has a potential to avoid unnecessary central compartment node dissection.

No MeSH data available.


Related in: MedlinePlus