Assessment of capillary density in systemic sclerosis with three different capillaroscopic methods.
OBJECTIVE
Capillary abnormalities, such as the enlargement and/or disappearance of capillary loops, occur early in the majority of patients with systemic sclerosis (SSc). The aim of this study was to compare three capillaroscopic methods of determining the capillary density in patients with SSc.


METHODS
Two of the three methods involved stereo-zoom microscopy at a magnification of 20 times, used either for direct counting, or with a camera and imaging software for determination of the capillary density on coded images. The third method was computerised nailfold video capillaroscopy with 300 x magnification using coded images. The capillary density (loops/mm) was determined on the fourth finger of the non-dominant hand with all three methods in 40 patients, 32 with limited cutaneous SSc (lcSSc) and 8 with diffuse cutaneous SSc (dcSSc), and in 21 healthy control subjects.


RESULTS
The median values of capillary density assessed with the three methods were: 4.3, 5.4 and 6.1 loops/mm in lc-SSc patients, 4.5, 5.0 and 6.3 loops/mm in dcSSc patients, and 7.0, 7.0 and 6.9 loops/mm in the controls. Capillary density was thus lower in lcSSc and dcSSc patients than in the controls according to all three methods. Agreement between the three methods was good in the controls. In patients, direct counting resulted in lower values than in the two computer-based methods.


CONCLUSIONS
Assessment of capillary density with three different methods showed good agreement between methods. All methods could differentiate between SSc patients and controls.
Department of Clinical Science, Lund University, Lund, Sweden. marie.wildt@med.lu.se
Marie
M
Wildt
Dirk M
DM
Wuttge
Roger
R
Hesselstrand
Agneta
A
Scheja
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002196:Capillaries / Q000473:pathology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D020678:Microscopic Angioscopy / Q000379:methods*; D008875:Middle Aged; D009262:Nails / Q000098:blood supply*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D045743:Scleroderma, Diffuse / Q000473:pathology*; D045745:Scleroderma, Limited / Q000473:pathology*; D012720:Severity of Illness Index; D013548:Sweden; D014741:Video Recording