Shear wave elastography findings in Immunoglobulin A Nephropathy patients: is it more specific and sensitive for interstitial fibrosis or interstitial fibrosis/tubular atrophy?

Figures & data

Table 1. Laboratory data, demographic and ultrasonographic features of all patients (mean values).

	Group 1 (n = 30)	Group 2 (n = 32)	p Value
Systolic BP (mmHg)	132.5 ± 12.5	120.7 ± 0.7	<.05
Diastolic BP (mmHg)	83.5 ± 7.7	81.2 ± 0.9	>.05
Pulse rate	84.3 ± 4.7	85.9 ± 6.1	>.05
Urea (mg/dL)	34.2 ± 2.1	25.2 ± 3.1	<.05
Creatinine (mg/dL)	1.71 ± 0.8	0.6 ± 0.1	<.05
FBG (mg/dL)	96.4 ± 30.1	92.2 ± 4.2	>.05
Proteinuria (mg/day)	1813.5 ± 1390.5	80.2 ± 21.5	<.05
eGFR (mL/minute)	58.9 ± 34.3	118.5 ± 4.9	<.05
URD (mm)	103.4 ± 15.1	112.3 ± 10.9	>.05
URPT (mm)	14.5 ± 3.1	22.6 ± 2.3	<.05
ROI skin distance (mm)	36.3 ± 12.1	37.2 ± 4.3	>.05
YM (kPa)	25.9 ± 13.6	9.9 ± 2.8	<.05

Italic values represents as significance values.

BP: blood pressure; FBG: fasting blood glucose; eGFR: estimated glomerular filtration rate; URD: ultrasonographic renal dimension; URPT: ultrasonographic renal parenchymal thickness; mm: millimeter; ROI: region of interest; YM: young module.

Table 2. Factors affecting YM.

	Estimate	Std. error	Wald	df	p Value	95% confidence interval
						Lower Bound	Upper Bound
Threshold	–1.838	2.107	0.761	1	.383	–5.968	2.291
	1.046	2.068	0.256	1	.613	–3.008	5.099
Location
Age	0.037	0.031	0.385	1	<.05	–0.025	0.098
eGFR	–0.066	0.014	20.706	1	<.05	–0.094	–0.038
ROI (mm)	0.013	0.031	0.178	1	.673	–0.048	0.074
Gender	0.921	0.816	1.274	1	.259	–0.678	2.521
IF	0.058	0.011	15.836	1	<.05	0.041	0.085
IFTA	0.031	0.026	0.379	1	.235	2.342	5.283

eGFR: estimated glomerular filtration rate; IF: interstitial fibrosis; IFTA: interstitial fibrosis/tubular atrophy; ROI: region of interest.

Multivariate ordinal logistic regression analysis to evaluate the importance of each variable in determining YM.

Figure 1. Patient 1: light microscopic images of renal tissue that stage T1 (moderate IFTA)-stage F0 (absence of IF) and their SWE image. (a) H&E ×200. (b) Masson’s trichrome ×200. (c) YM = 7.2 kPa (compatible with the stage F0 (absence of IF)).

Figure 2. Patient 2: light microscopic images of renal tissue that stage T1 (moderate IFTA)-stage F2 (severe IF) and their SWE image. (a) H&E ×200. (b) Masson’s trichrome ×200. (c) YM = 29.7 kPa (compatible with the stage F2 (severe IF)).

Figure 3. Patient 3: light microscopic images of renal tissue that stage T2 (severe IFTA)-stage F1 (moderate IF) and their SWE image. (a) H&E ×200. (b) Masson’s trichrome ×200. (c) YM = 21.3 kPa (compatible with the stage F1 (moderate IF)).

Table 3. Sensitivity, specificity, PPV, NPV, accuracy of SWE, URD, URPT, and eGFR to diagnose presence of IF.

	Sensitivity	Specificity	PPV	NPV	Accuracy
SWE	89% (95% CI, 86.3–100)	90% (95 % CI, 82.4–100)	91% (95% CI, 86.3–100)	92% (95% CI, 82.4–100)	93% (95% CI, 85.2–100)
URD	43% (95% CI, 81.2–100)	84.8% (95% CI, 82.3–100)	88.5% (95% CI, 85.6–100)	42% (95% CI, 84.1–100)	57% (95% CI, 81–100)
URPT	52% (95% CI, 81.2–100)	85.2% (95% CI, 82.3–100)	86.7% (95% CI, 85.6–100)	56% (95% CI, 84.1–100)	77% (95% CI, 86.1–100)
eGFR	82% (95% CI, 85.4–100)	92% (95% CI, 82.1–100)	92% (95% CI, 85.4–100)	83% (95% CI, 81.4–100)	94% (95% CI, 89.2–100)

PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; SWE: shear wave elastography; URD: ultrasonographic renal dimensions; URPT: ultrasonographic renal parenchymal thickness; eGFR: estimated glomerular filtration rate.

Table 4. Sensitivity, specificity, PPV, NPV, accuracy of SWE, URD, URPT, and eGFR to diagnose presence of IFTA.

	Sensitivity	Specificity	PPV	NPV	Accuracy
SWE	65% (95% CI, 86.3–100)	51% (95% CI, 82.4–100)	78.1% (95% CI, 86.3–100)	49% (95% CI, 82.4–100)	54% (95% CI, 85.2–100)
URD	32% (95% CI, 83.5–100)	54.8% (95% CI, 86.3–100)	67.5% (95% CI, 80.7–100)	32% (95% CI, 81.1–100)	77.8 (95% CI, 82.1–100)
URPT	52% (95% CI, 82.2–100)	85.2% (95% CI, 84.3–100)	56.7% (95% CI, 80.7–100)	46% (95% CI, 84.1–100)	67% (95% CI, 86.1–100)
eGFR	66% (95% CI, 81.2–100)	84.6% (95% CI, 82.3–100)	68.2% (95% CI, 81.2–100)	55% (95% CI, 80.1–100)	68% (95% CI, 85.1–100)

PPV: positive predictive value; NPV: negative predictive value; CI: confidence interval; SWE: shear wave elastography; URD: ultrasonographic renal dimensions; URPT: ultrasonographic renal parenchymal thickness; eGFR: estimated glomerular filtration rate.