Table 2 Characteristics of included studies

Akopov and Whitman [19]

In-hospital

AIS

TCD

MRA, CT

12

Only the results of TCD that was performed within 24 h after ictus were analysed

MRA was performed together with the first TCD examination for seven patients (included in the analysis). For all others, MRA was performed 24–72 h after the ictus and close to the second TCD (not included in the analysis)

Unclear—TCD was performed by the authors

Not specified

2 MHz

Bar et al. [23]

In-hospital

AIS

TCCS ± contrast enhancement

CTA

31

Within 3 h

20 min

Three skilled sonographers with at least 5 years of experience in ultrasound diagnostics

Sector

2–4 MHz

Boddu et al. [24]

Unclear—“in the laboratory”

AIS

TCD

MRA

128

Not specified—within 24 h in 33% of participants and within maximum 29 h in 67% of participants

From 30 to 300 min (median 60 min)

Credentialed neurosonologist

Not specified

2 MHz

Brunser et al. [25]

In-hospital

AIS

TCD (PMD)

CTA

100

Mean 468 min ± SD 343.2 min

Mean 77.8 min ± SD 88.5 min

Experienced sonographer certified by the American Society of Neuroimaging

Not specified

Gerriets et al. [26]

In-hospital

AIS, MLS

TCCS

CT

40

Only results of TCCS examination that were performed 8 ± 3 and 16 ± 3 h from onset were analysed

6 h

Unclear—“three investigators”

Sector

2.5 MHz

Gerriets et al. [27]

In-hospital

AIS

TCCS ± contrast enhancement

CTA, MRA, DSA

58

Immediately on admission, within 6 h from symptom onset (mean 3.4 h)

Mean time difference = 0.8 h in 14 patients; 6.1 in 18 patients

Doctors with at least 1 year of experience in the field of colour-coded duplex sonography of the brain-supplying arteries

Sector

2–2.5 MHz

Goertler et al. [41]

Presumably in-hospital, department of neurology

AIS

TCCS

Contrast-enhanced TCCS

23

Within 5 h

Not specified but both tests performed within 5 h from symptom onset

A sonographer

Sector

2–2.5 MHz

Guan et al. [28]

In-hospital

AIS

TCD

CTA

128

The mean time from symptom onset to admission was 12.3 (10.1) hours

The mean time from admission to TCD was 15.5 (SD 10.1) minutes

The mean time interval between both examinations was 89.7 (77.8) min

65% patients—less than 30 min difference between them; 25%, 31–90 min; 15%, more than 90 min but less than 180 min

Experienced sonographer

Not specified

2 MHz

Kadimi et al. [43]

Not specified—presumably in-hospital

AIS

TCD

CT

4

Within 6 h

Not specified—both CT and TCD were performed within 6 h of the onset of symptoms

Not specified

Sector

2 MHz

Kenton et al. [29]

In-hospital

AIS

TCCS

MRA

30

Ranged from 4 to 24 h, mean 15.4 h

Within 4 h, range 15 min to 4 h; median, 2 h

Not specified

Curved phase array

2.25 MHz

Kern et al. [30]

In-hospital, stroke unit

ICH

Native transcranial b-mode ultrasound, UPI with contrast enhancement

CT

12

Unclear—on day 1 as soon as possible after admission

4.1 ± 2.5 h on day 1 (CT first)

Sonographers

Sector

2–4 MHz

Kukulska-Pawluczuk et al. [44]

In-hospital

ICH, MLS

TCCS

CT

39

The time between initial symptoms of focal neurologic deficit and hospital admission ranged from 1.5 to 48 h with a median of 5.9 h. Index test was performed not later than 12 h after initial CT which was done directly upon admission

Not more than 12 h

Unknown

Sector

2.5 MHz

Leanyvari et al. [45]

Unclear

AIS

TCD

CT

12

Within 12.5 ± 8 h after stroke onset or not more than 24.5 h

TCD measurements were made before or no more than 4 h after CT

Not specified

Not specified

2 MHz

Matsumoto et al. [31]

In-hospital

ICH

TCCS

CT

20

Within 21 h (within 12 h of the CT study which was performed 4.6 ± 4.4 h from symptom onset)

Within 12 h (mean 3.9 ± 4.1 h)

Not specified

Sector

2.5 MHz

Nasr et al. [32]

Outpatient, TIA clinic

AIS

TCCS

MRI-3D-TOF angiography

116

Unclear but presumably within 24 h from the onset

4 h

Unclear

Not specified

Ovesen [42]

In-hospital

ICH

Transcranial b-mode ultrasound

CT, CTA

25

Within 4.5 h

Mean 61.1 min (SD 26.6)

Unclear (“a single observer”)

Sector

1.7–3.1 MHz

Panerai et al. [20]

In-hospital

AIS

TCD

MRI-DWI

11 plus 9 healthy controls

Within 48 h

Median time interval 2 h (range 0.5–8 h)

Unclear—performed “in a dedicated cardiovascular research laboratory”

Not specified

2 MHz

Rathakrishnan et al. [33]

In-hospital

AIS

TCD

CTA

15

Not specified

Within 24 h

Not specified, a stroke neurologist credentialed in cerebrovascular ultrasound interpreted the TCD findings

Not specified

2 MHz

Seidel et al. [34]

In-hospital

AIS, HT

TCCS

CT

32

For the purpose of the current review only TCCS findings which were obtained < 12 and 24 ± 4 h from symptoms onset were analysed

Unclear but before TCCS

Sonographer

Sector

2–4 MHz

Seidel et al. [35]

In-hospital

AIS, HT

TCCS

CT, MRI in individual cases

55

Within 32 h (mean time 10.6 h (SD, 7.2; median, 8.5; interquartile range, 6.5 h after stroke symptom onset)

Within mean time of 14 h (CT was performed immediately after stroke symptom onset with mean 3.3 h; SD, 3.0; median, 2.0; interquartile range, 3.75)

The ultrasound investigator

Sector

2 MHz

Stolz et al. [36]

In-hospital

AIS, ICH, MLS

TCCS

CT

61

Unclear, presumably within 24 h

3–12 h

Four sonographers with sufficient experience with the method

Not specified

2–2.5 MHz

Tang et al. [37]

In-hospital, stroke unit

ICH, MLS

TCCS

CT

51

Unclear but presumably within 24 h because time from symptom onset to reference imaging was 4.1 ± 3.7 h

Not more than 12 h, average interval was 5.9 ± 4.0 h

Well-trained and experienced sonographers

Sector

2 MHz

Tsivgoulis et al. [38]

Emergency department

AIS

TCD

CTA

132

Within 24 h

Range 10–130 min (median 35 min)

Experienced sonographers

Not specified

2 MHz

Tsivgoulis et al. [39]

Emergency room

AIS

TCD (PMD)

CTA, MRA, DSA

213

Within 24 h

Presumed 24 h, angiography was performed within 48 h from ictus

Stroke neurologists with specialised training and credentials in cerebrovascular ultrasound

Not specified

2 MHz

Viola et al. [21]

In-hospital

AIS

TCD (3D)

MRA, CT

47 plus 67 healthy controls

Within 3–24 h

Unclear, presumably not more than 24 h—both tests were performed 3–24 h from onset

Not specified

Not specified

2 MHz

Wada et al. [40]

Not specified

AIS

TCCS

DSA

40

Within 24 h

Not specified—“immediately before cerebral angiography”

Unclear

Not specified

2–3 MHz, 3700 Hz pulse repetition frequency, low-pass filter was 50 Hz

Zubkov et al. [46]

In-hospital

AIS

TCD

CTA

31

Approximately 30 h after symptom onset

Unclear, presumably within 24 h

Experienced ultrasonographers

Not specified

2 MHz