vascular malformations ( vms ) of the hand are rare and can have a variable clinical progression .
such lesions may expand with the growth of the patient or progressive ectasia , but they do not proliferate . similarly , they do not undergo spontaneous resolution .
they can be classified as simple ( capillary , lymphatic , venous , or arteriovenous ) , combined ( defined as two or more vms found in one lesion ) , or in association with other anomalies .
arteriovenous malformations ( avms ) , including arteriovenous fistulas ( avfs ) , can present as congenital vascular lesions arising from errors in embryonic vasculogenesis or acquired in life secondary to trauma .
avms are characterized by high - velocity turbulent blood flow from an artery to a vein , bypassing a normal capillary bed and can be clinically staged according to shobinger .
high - flow avms of the upper limb can be classified as type a : anomalies with either single or multiple avfs , aneurysms , or ectasias of the arterial side of the circulation ; type b : anomalies with micro- or macro - fistulas that were localized to a single axial artery of the limb , hand , or digit ; type c : diffuse arteriovenous anomalies with macro- and micro - fistulous connections involving all tissues of the limb .
angiography is the current gold standard imaging modality and in majority of avms displays a central core , or nidus , of abnormal connections from enlarged feeding arteries to draining veins .
surgical or endovascular treatment can be complex with risk of uncontrollable bleeding , incomplete resection , and recurrence including rapid collateralization of adjacent arteries .
this may be complicated by skin necrosis leading to amputation and associated loss of function .
thermal imaging is a non - invasive , non - contact technology that does not require intravenous contrast agents .
it has been used experimentally in various areas of plastic surgery including free - flap monitoring , perforator and perforasome mapping , and burn depth assessment .
the infrared radiation that is emitted is a surrogate measure of blood flow and can be objectively quantified .
the majority of thermal imaging cameras measure infrared radiation in the 115 m range , with most clinical applications focusing on the long - wave infrared from 7 to 14 m .
recent smartphone - based systems have brought low - cost thermal imaging to the clinic as high - resolution industrial systems may be cost - prohibitive .
we present the case of a patient with an avm affecting the hand in which thermal imaging has been used as an adjunct to capture baseline images to allow monitoring of progression .
a 39-year - old female was referred to our regional peripheral vascular anomalies clinic with a 24-year history of a lesion affecting the left nondominant hand which started as a pea size mass , progressing to involve the palm , digits , and forearm .
she underwent a surgical debulking procedure at the age of 17 , but the lesion continued to expand .
schooling and work were unaffected till the age of 21 ; however , due to pain , weakness , and coordination difficulties , she was not able to return to employment . on examination , an extensive vascular anomaly was noted to involve the palm , index and middle fingers , and distal forearm and wrist [ figure 1a ] , with bruit and a palpable thrill .
an ultrasound doppler scan and magnetic resonance angiography confirmed the diagnosis of a high - flow avm , and digital subtraction angiography was used to define the anatomy of the malformation and shows features of a type - a avm [ figure 1b ] .
nerve conduction studies showed no evidence of compression neuropathy but some axonal loss , presumably due to mild ischemic changes secondary to the avm .
39-year - old female with a 24-year history of a lesion affecting the left nondominant hand diagnosed as a congenital arteriovenous malformation of the left hand and wrist .
( a ) photograph of the hand shows the arteriovenous malformation visibly involves the radial aspect of the palm and index finger and ( b ) digital subtraction angiography confirms a type - a arteriovenous malformation of the radial artery , palmar arch , and digital arteries of the index and middle fingers .
there is minimal contrast agent seen in the thumb , ring or little finger digital arteries ( black arrow ) .
steal  affecting the thumb , ring and little fingers ( white arrows ) , and ( d ) thermal image of the unaffected right hand for comparison . to monitor the 
steal  phenomenon affecting the thumb and ulnar - sided digits , a thermal image was recorded in the clinic using an flir sc660 thermal imaging camera ( flir systems inc . ,
images were recorded at 22c and 50% relative humidity at a distance of 70 cm after exposure of the hand for 3 min to allow surface cooling of the skin
. baseline images of the affected [ figure 1c ] and unaffected hand [ figure 1d ] were recorded for future monitoring of the avm with regards to progression of the lesion or of the steal phenomenon . to date , the patient has declined any radiological or surgical intervention to date and is managed with a compression garment and simple analgesia for pain relief .
avms of the hand are more likely to cause functional impairment than those at other sites , and surgical and/or embolization may have catastrophic consequences to the digits . a comprehensive review by upton et al .
, noted that only 12% of the upper limb vms were avms ( 4 type a , 15 type b , and 14 type c ) .
although avms are rare , they exhibit more aggressive and unpredictable clinical behavior than other forms of vms .
the fast turbulent flow created between the directly connected arterial and venous systems is responsible for a destructive hemodynamic effect that determines clinical symptoms and potentially high recurrence rates .
complete surgical excision in conjunction with embolization sometimes may be impossible without threatening the viability of the digits , and limited debulking may lead to recurrence .
avms can be located in various anatomic areas and sometimes occur simultaneously in several regions . in a study by vainyte et al .
, extracranial avms were analyzed , of which 80.4% were located in the extremities and the gluteal region , allowing easy access for thermal imaging . at present , progression of avms
there is no non - invasive objective test that can determine the evolution or expansion of the lesion , or associated distal vascular steal that may occur in the extremities .
although upton et al . , included distal vascular steal in the type - c avm classification , we have shown that this may still occur in type a lesions and could lead to symptoms requiring surgical intervention .
although no skin or trophic changes have been noted in the reported case , a combination of angiography and thermal imaging has indicated the presence of markedly reduced distal perfusion , which may be subclinical at present .
the natural history of avms of the hand can be variable , and thermal imaging provides an objective measure of progression that can determine the optimum time for surgery and/or embolization , balancing the risk of iatrogenic digital ischemia versus inherent vascular steal .
we suggest that thermal imaging is an adjunct that can be used in addition to clinical examination and/or angiography for the diagnosis and follow - up of arteriovenous malformations , to monitor progression or vascular steal , and also for recording recurrence after surgical excision . with the advantage of being a non - invasive imaging modality that does not require intravenous contrast , or ionizing radiation exposure
 vascular malformations of the hand are rare . 
 angiography is the current gold standard imaging modality . 
 thermal imaging is an emerging noninvasive , noncontact technology that does not require intravenous contrast agents . 
 we present the case of a patient with an arteriovenous malformation affecting the hand in which thermal imaging has been used as an adjunct to capture baseline images to allow monitoring of progression . 
 we suggest that thermal imaging provides an adjunct that can be used in addition to clinical examination and/or angiography for the diagnosis and routine follow - up of conservatively managed arteriovenous malformations , to monitor progression or vascular steal , and also for recording recurrence after surgical excision for which there is known to be a significant incidence . with the benefit of being a noninvasive imaging modality that does not require intravenous contrast , or ionizing radiation exposure , office - based thermal imaging may become commonplace . 
INTRODUCTION
CASE REPORT
DISCUSSION
CONCLUSIONs
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