Table 1.

Characteristics of the patients.

Patient ID	Demographics							Laboratory/Clinical			Venular density n./8 cm2
	Age	Sex	Educationa	Haemoglobin, g/dL	HbS, %	HbF, %	HU	MRI findings^	Clinical complications	HVLT-Rb, %	Total	Short (3–5 mm)	Long (9–10 mm)
01	31	F	4	11.0	89.7	5.2	Yes	BGpv, BGc	AVNc, retinopathy, ACSd	100	54	22	2
02	22	M	2	11.1	78.1	6.7	No	HC, BGpv	ACS, aplastic crisis, splenic sequestration	122	45	15	12
03	40	M	2	8.4	86.8	8.0	Yes	HC, BGpv	PHe, leg ulcers, priapism, retinopathy	29	11	10	0
04	20	M	1	10.1	86.1	11.3	Yes	HC	AVN	62	29	20	2
05	39	F	4	10.9	71.4	26.8	Yes		ACS, PH	100	35	20	4
06	34	F	2	6.8	70.4	27.6	Yes	SCI	Right occipital silent infarct, ACS, bone infarctions, PH	NAf	28	27	0
07	21	F	1	9.3	NA	NA	No	HC, BGpv	ACS, AVN, PH	67	32	23	2
08	35	F	4	9.4	77.1	7.5	Yes	BGc	Retinopathy	64	47	26	8
09	22	F	3	10.1	59.9	20.4	Yes	HC, BGpv	Retinopathy	73	33	11	7
10	46	F	2	9.7	58.1	24.8	Yes	HC, BGpv	Leg ulcers, PH	83	27	10	5
11	24	F	3	10.1	87.8	8.9	No	BGc	ACS	86	23	7	6
Median rangeg	31.0		2.0	10.1	77.6	10.1				78.0	32.0	20.0	4.0
	22–39		2–4	9–11	68–87	7–25				63–100	27–45	10–23	2–7

^a1 = less than high school, 2 = high school, 3 = some college, 4 = college completed.

^bHU: Hydroxyurea

^{^}All patients displayed perivascular spaces in the frontal white matter and varying levels of iron deposition. BGpv: perivascular spaces in the basal ganglia; HC: hippocampal cysts; BGc: basal ganglia cysts HVLT-R = Hopkins Verbal Learning Test – Revised. Results are expressed as % retention (delayed recall score / highest correct trial score).

^cAVN = avascular necrosis.

^dACS = acute chest syndrome.

^ePH = pulmonary hypertension by echocardiographic criteria (tricuspid regurgitant jet velocity > 3.0 m/s).

^fNA = not available because the patient left the facility before HVLT-R testing.

^gDenotes interquartile range.