Diagnostic Value of Superb Microvascular Imaging of the Rotator Cuff Interval for the Early Diagnosis of Frozen Shoulder

Figures & data

Figure 1 Measurement of coracohumeral ligament and capsule thickness. (A) Coracohumeral ligament. The arrow indicated coracohumeral ligament; (B) Glenohumeral joint capsule. The arrow indicated glenohumeral joint capsule.

Abbreviations: CO, coracoid; HH, head of humerus.

Figure 2 The blood flow signals. (A) Grade 0: no blood flow signals; (B) Grade 1: one or two dot-like blood flow signals; (C) Grade 2: three or four short linear blood flow signals; (D) Grade 3: branching or mesh-like blood flow signals.

Table 1 Characteristics of the Patients

Characteristics	Healthy Controls (n=77)	Patients (n=79)	P
Sex			0.432
Male	42 (54.5)	48 (60.8)
Female	35 (45.5)	31 (39.2)
Hypertension	6 (7.8)	13 (16.5)	0.098
Diabetes	2 (2.6)	4 (5.1)	0.423
Thyroid Disease	4 (5.2)	15 (19.0)	0.008
Medication and Rehab history	0 (0.0)	3 (3.8)	0.084
BMI			0.789
Underweight	5 (31.3)	11 (68.8)
Normal	49 (57.6)	36 (42.4)
Overweight	13 (34.2)	25 (65.8)
Obese	9 (60)	6 (40)
Age (years)	55.09±9.18	57.05±10.61	0.219
Height (cm)	167.50±9.86	169.26±8.85	0.242
Weight (Kg)	66.02±8.00	68.18±11.09	0.167
Pain score (points)	1.00±0.00	6.00±2.00	<0.001

Table 2 Ultrasound Feature Indicators Between the Two Groups

Characteristics	Healthy Controls (n=77)	Patients (n=79)	P
Rotator cuff gap hypoechoic	37 (48.1)	64 (81.0)	<0.001
Coracohumeral ligament thickness (mm)	2.03±0.97	2.60±1.01	<0.001
Glenohumeral joint capsule thickness (mm)	2.46±1.17	3.10±0.99	<0.001
SMI blood flow grading			<0.001
0	0 (0.0)	0 (0.0)
1	59 (76.6)	14 (17.7)
2	18 (23.4)	45 (57.0)
3	0 (0)	20 (25.3)
PDUS blood flow grading			0.014
0	10 (13)	7 (8.9)
1	50 (64.9)	40 (50.6)
2	17 (22.1)	29 (36.7)
3	0 (0)	3 (3.8)

Abbreviations: SMI: superb microvascular imaging; PDUS: power Doppler ultrasound.

Table 3 ROC Analysis

Test Result Variable	AUC	Standard error	P	95% CI	Youden index	Cutoff	Sensitivity (%)	Specificity (%)	DeLong test (vs SMI)
SMI blood flow grading	0.824	0.0338	<0.0001	0.755–0.880	0.589	1	82.28	76.62	–
PDUS blood flow grading	0.600	0.0453	0.0265	0.519–0.678	0.184	1	40.51	77.92	<0.001
Rotator cuff gap hypoechoic	0.665	0.043	0.001	0.585–0.738	0.330	1	81.01	51.95	0.001
Coracohumeral ligament thickness	0.643	0.046	0.002	0.563–0.718	0.426	2.3	60.76	81.82	0.003
Glenohumeral joint capsule thickness	0.651	0.048	0.002	0.571–0.726	0.488	2.73	70.89	77.92	0.005

Figure 3 Receiver operating characteristics (ROC) curves for different features.

Table 4 Activity in the Patient Group in Relation to the SMI Blood Flow Grading

Activity	SMI Blood Flow Grading				P
	0 (n=0)	1 (n=14)	2 (n=45)	3 (n=20)
External rotation <30° (n=65)	0 (0.0)	7 (10.6)	41 (62.1)	18 (27.3)	0.007
Internal rotation <30° (n=32)	0 (0.0)	3 (9.4)	22 (68.8)	7 (21.9)	0.630
Abduction <30° (n=61)	0 (0.0)	5 (8.2)	40 (65.6)	16 (26.2)	0.013
Flexion <30° (n=58)	0 (0.0)	10 (17.2)	35 (60.3)	13 (22.4)	0.562

Data Sharing Statement

All data generated or analyzed during this study are included in this published article.