You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
injuries and accidents are the main causes of morbidity , limb amputation and mortality worldwide .
these injuries need prompt intervention and management due to limited time of tissue viability ( 1 ) .
if hard signs of vascular injuries ( i.e. pulsatile hemorrhage , expansile hematoma , palpable thrill and pulselessness ) exist , an urgent surgical intervention would be needed ( 2 ) .
there are some cases in which surgeon can not precisely judge the condition due to coexistence of other injuries and lack of classic clinical signs ( 3 ) . in such instances , which are not rare
although its sensitivity and specificity values for detecting vascular injuries have been reported as 95% to 100% and 90% to 98% , respectively , it is an aggressive and expensive modality , which needs special conditions ( 4 , 5 ) .
nonetheless , among these suspicious cases , the results of angiographies have been normal or near normal and even a small defect might be noted , which would not change the management course of such cases with trauma ( 5 ) .
hence , many have tried to substitute angiography with noninvasive modalities such as serial physical examination alone or in combination with other methods including ankle brachial index ( abi ) , arterial pressure index ( api ) or doppler ultrasonography ( usg ) ( 6)color doppler usg is a noninvasive method widely used for the diagnosis of vascular diseases because of its acceptable accuracy in detection of vascular lesions ( 7 ) .
in this study , we compared the accuracy of color doppler usg in the diagnosis of traumatic vascular injuries with that of angiography .
this study was performed in one year and included 75 patients with probable arterial injury in extremities referred to the radiology department of imam reza hospital to undergo angiography .
examination was performed while the patient was prepared for angiography to prevent wasting time in trauma management .
we used a siemens g40 color doppler usg ( germany ) device with a 6- to 10-mhz linear vascular probe .
depending on the site of injury , blood flow condition inside the artery and doppler waveform patterns were recorded on three distinct points as follows : on ulnar and radial arteries in wrist , brachial artery in antecubital fossa , and axillary artery in axillary fossa for upper limb ; and on anterior and posterior tibial arteries in ankle , popliteal artery in popliteal fossa and common and superficial femoral arteries in inguinal region of the lower limb . in the presence of any change in normal doppler pattern ,
normal doppler study wave was defined as a triphasic pattern in all examination points ( figure 1 ) .
this triphasic pattern has three components : rapid antegrade flow with a peak in systole , early diastolic reversal of flow and slow antegrade flow at late diastole .
any other patterns such as damping were considered as abnormal . a , common femoral artery .
c , anterior tibial artery . after performing angiography , normal finding on angiography was defined as a full column linear and regular intraluminal contrast pattern .
abnormal findings were defined as any interruption of the normal continuity or irregularity of the intraluminal borders ( e.g. arterial emboli ) .
eleven of 75 cases were female ( 14.7% ) and 64 ( 85.3% ) were male .
fifty - eight patients ( 77.3% ) had lower limb trauma , while upper limb trauma was seen in 17 patients ( 22.7% ) .
the most common cause of trauma was motor vehicle accidents ( 77.3% ) ( table 1 ) .
thirty - six patients ( 48% ) had normal angiography findings , while evidences of arterial injury were noticed in 39 patients ( 52% ) .  
doppler ultrasound assessments showed a normal pattern in 35 cases ( 46.7% ) and abnormal findings in 40 ones ( 53.3% ) ( table 2 ) .  
, our findings showed a sensitivity of 94.9% and a specificity of 91.7% for doppler usg . positive and negative predictive values of doppler usg were 92.5% and 94.3% , respectively .
patients with abnormal findings on doppler usg were carefully evaluated for a cut - off point indicating a true and obvious arterial injury ; however , this finding was reported only in 26 cases ( 34.7% ) .
considering doppler cutoff point , sensitivity and specificity values of doppler usg were 66.6% and 100% , respectively , and its positive and negative predictive values were 73% and 100% , respectively .
motor vehicle accidents are the most common causes of injury in urban and suburban areas ( 8) . among different types of vascular injuries , extremity vascular injuries are one of the most critical types of limb injuries that could be life or limb threatening ( 6 ) .
arteriography as the gold standard to diagnose arterial injuries has a sensitivity of 95% to 100% and specificity of 90% to 98% .
nonetheless , due to its invasive nature , it is associated with some complications in 2.6% of patients and even higher risk in patients with trauma and other coexistent injuries .
transferring a critically - ill patient to angiography ward and injecting contrast media might make the situation even worse and cause serious problems ( 9 ) .
therefore , considering these special conditions , performing angiography in any multiple trauma case with findings suggestive of arterial limb injury is questionable .
a recent systematic review of 51 articles showed that computed tomography angiography ( cta ) is the main replacement of angiography ( 10 ) . nonetheless , color doppler usg is nonaggressive and less expensive as a bedside method for saving patient s time and minimizing potential risks of other diagnostic interventions ( 7 ) .
bynoe et al . reported sensitivity and specificity of 95% and 99% for doppler usg in detection of limb vascular injuries , respectively ( 11 ) .
reported similar results and according to the literature review , both sensitivity and specificity of doppler usg to diagnose traumatic limb vascular injury are higher than 95% , which seems acceptable for a screening and diagnostic method ( 12 , 13 ) . in our study ,
doppler usg had a sensitivity of 94.8% and specificity of 91.6% to detect vascular injuries with positive and negative predictive values of 92.5% and 94.2% , respectively .
considering doppler cutoff point , sensitivity and specificity of doppler usg were 66.6% and 100% , respectively , and its positive and negative predictive values were 73% and 100% , respectively .
there were only three cases with abnormal findings in doppler and normal findings in angiograms , two of which were due to an arterial spasm ( one in posterior tibial artery and another in the radial artery ) .
the third one was due to hematoma on the fractured forearm , which pushed the artery away from its normal position and therefore , the normal path of artery could not be detected well by doppler usg , while angiography showed all the artery length and its shifting to the medial side .
there were two cases with normal findings in doppler usg and abnormal findings in angiograms .
one case had pseudo aneurysm of the distal superficial femoral artery ( due to knee dislocation ) , which was not detected by doppler usg because of its thick dressings .
another one was a case of cutting of proximal portion of the posterior tibial artery on angiograms , while normal wave pattern was recorded on doppler usg because of collateral arteries .
doppler usg was not quite accurate to detect the lesion in such instances as limb splints , in situ hematoma , or patient s pain leading to lack of cooperation for optimal evaluations .
color doppler usg fulfilled required criteria of a screening test with a high sensitivity , acceptable specificity , availability , and being inexpensive and noninvasive ; therefore , it might be considered as a suitable screening test for those with suspicious vascular injury .
although doppler usg has some diagnostic limitations in locating the exact point of artery cut - off point and the traumatized area , it would be recommended as a suitable screening test in patients with limb trauma suspicious for vascular injuries because of its high sensitivity and specificity as well as availability , inexpensiveness and noninvasiveness .
background : traumatic events are one of the major causes of arterial injuries . 
 physical examination is not a good predictor of the extent of injuries and arteriography is considered as the gold standard for this purpose . in the recent years , noninvasive modalities are increasingly replacing diagnostic arteriography . 
 color doppler ultrasonography ( usg ) is an excellent method to investigate arterial diseases.objectives:the present study aimed to evaluate the diagnostic value of color doppler usg compared to conventional angiography in traumatic arterial injuries of extremities.patients and methods : seventy - five patients with extremity trauma suspicious for arterial injury were examined by color doppler usg just before angiography . 
 doppler pattern and flow states were assessed , then angiography was performed . 
 the results of duplex usg were compared with angiography.results:color doppler usg had a sensitivity of 95% and specificity of 98% in diagnosis of arterial injury . 
 positive and negative predictive values of doppler usg were 92.5% and 94.2% , respectively.conclusions:color doppler usg can be used as a reliable modality with acceptable sensitivity and specificity values to screen hemodynamically stable patients with limb trauma suspicious for arterial injury .