Eur J Plast Surg (1999) 22:58±61
E. Zetterman ´ A. Salmi ´ S. Suominen ´ A. Karonen
Effect of cooling and warming on thermographic imaging
of the perforating vessels of the abdomen
Received: 4 March 1998 / Accepted: 8 December 1998
This paper has been presented at the 5. Annual Meeting of
EURAPS, Innsbruck, 25 May 1996.
E. Zetterman (
) ´ A. Salmi ´ S. Suominen ´ S. Asko-Seljavaara
Department of Plastic Surgery, Helsinki University Central Hospital,
Töölö Hospital, Topeliuksenkatu 5, FIN-00260 Helsinki, Finland
Tel. +358-9-4711; Fax +358-9-47187570
Helsinki Institute of Technology, Helsinki, Finland
Abstract The skin islands of musculocutaneous flaps are
nourished by perforating arteries. An easy method for ac-
curately locating these vessels preoperatively would be
valuable in flap design. Thermography is being developed
in our center as a tool to locate the perforating vessels,
which appear as ªhot spotsº on thermographic images.
The abdominal perforators of 16 women were mapped
out after warming or cooling the skin with COLDI-micro
thermocushions. In group I (n=8) the thermo packs were
applied to the lower abdominal skin for 30 s and in group
II (n=8) for 300 s. In both groups all hot spots disappeared
after warming. After cooling, the hot spots were clearer
and more readily visible than at room temperature. The
longer cooling time (300 s) gave a 3.4 times better con-
trast (p=0.03) than the shorter cooling time (30 s). The
longer the cooling time, the longer the hot spots were vis-
ible. This work shows that cutaneous perforators can be
sharply mapped preoperatively using thermography after
simple bed-side cooling.
Key words Thermography ´ Perforators ´ Free flaps ´
In plastic surgery, flap design requires precise knowledge
of the human anatomy and continues to be based on
knowledge acquired from cadaver dissections [7, 19, 21,
23]. Anatomical studies have shown the existence of
276 major cutaneous perforators . The anatomy of cu-
taneous vessels varies between individuals and in 2/3 of
people also between the left and right sides of the body
[12, 13, 21]. Doppler ultrasound, colour flow Doppler
and magnetic resonance imaging (MRI) have all been
used to detect skin vessels [1, 3, 6, 9, 13, 20]. The reliabil-
ity of these techniques is good, but limitations due to phy-
sician and machine severely hamper their everyday use.
Infrared thermography has been used since the late
1950s to monitor thermal radiation from the skin [14,
16, 22, 24]. Modern thermocameras can detect tempera-
ture differences of `0.1C. The temperature of the skin
surface is proportional to local blood flow, local metabol-
ic processes and heat radiation from the deeper tissues .
Under normal circumstances, the skin surface temperature
is influenced by underlying structures from a depth of
about 2 cm .
Musculocutaneous and direct cutaneous perforators
bring warm blood to the skin and are seen in thermo-
graphic images as warm areas called ªhot spotsº .
Thermography has been used for localising perforators
and for studying blood flow in free transverse rectus ab-
dominis musculocutaneous flaps (TRAM) both during
and after surgery .
The literature contains two Japanese reports of the pre-
operative use of thermography after rapid cooling (3±10 s)
[10, 11]. In these, short cooling rendered the hot spots
more visible but the effects of different temperatures were
not further analysed. The present idea was to use the
thermocamera as a bed-side tool for the design and study
of flaps and also for the postoperative monitoring of free
flaps. To this end it was necessary to establish the optimal
temperature at which skin perforators could be localised.
The abdominal skin was chosen for this study because its
anatomy and perforating vessels are well documented,
and because the free TRAM flap is one of the most fre-
quently used musculocutaneous flaps [4, 5].
Material and methods
The study comprised 16 female volunteers, whose body mass image
) ratio was 22.5 (range 18.4±31.6). With the exception