http___medlib.mef.hr_1663__1.xml
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Ajduk, Marko and Pavić, Ladislav and Bulimbašić, Stela and Šarlija, Mirko and Pavić, Predrag and Patrlj, Leonardo and Brkljačić, Boris (2009) Multidetector-row computed tomography in evaluation of atherosclerotic carotid plaques complicated with intraplaque hemorrhage. Annals of Vascular Surgery, 23 (2). Abstract Objective: To determine sensitivity and specificity of multidetector-row computed tomography in detecting atherosclerotic carotid plaques complicated with intraplaque hemorrhage. ----- Material: Carotid plaques from 31 patients operated for carotid artery stenosis. ----- Methods: Results of preoperative multidetector-row computed tomography analysis of carotid plaques were compared with results of histological analysis of the same plaque areas. Carotid endarterectomy was performed within one week of multidetector-row computed tomography. American Heart Association classification of atherosclerotic plaques was applied for histological classification. ----- Results: Median tissue density of carotid plaques complicated with intraplaque hemorrhage was 22 Hounsfield units. Median tissue density of noncalcified segments of uncomplicated plaques was 59 Hounsfield units (p=0.0062). The highest tissue density observed for complicated plaques was 31 Hounsfield units. Multidetector-row computed tomography detected plaques complicated with hemorrhage with sensitivity of 100% and specificity of 64.7%, with tissue density of 31 Hounsfield units as a threshold value. ----- Conclusion: Multidetector-row computed tomography showed high level of sensitivity and moderate level of specificity in detecting atherosclerotic carotid plaques complicated with hemorrhage. Actions (login required) Downloads Downloads per month over past year
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Ajduk, Marko (2009) Mogućnost detekcije potencijalno vulnerabilnih karotidnih plakova višeslojnom kompjuteriziranom tomografijom - korelacija rezultata analize sa nalazima histološke analize. PhD thesis, Sveučilište u Zagrebu. Croatian abstract Moždani udar treći je vodeći uzrok smrti i drugi po učestalosti uzrok smrti među kardiovaskularnim bolestima u razvijenim zemljama. Aterosklerotski plak karotidne arterije uzrok je većine moždanih udara u bolesnika kod kojih je prisutan, bilo da uzrokuje embolizaciju u moždani krvotok bilo da dovodi do značajnih hemodinamskih poremećaja cerebralne cirkulacije. Predilekcijsko mjesto za nastanak aterosklerotskog plaka na karotidnom stablu je bifurkacija zajedničke karotidne arterije odnosno bulbus unutarnje karotidne arterije. Velike prospektivne randomizirane studije pokazale su korist od endarterektomije unutarnje karotidne arterije u simptomatskih bolesnika te u nešto manjoj mjeri i u onih bez simptoma. Zbog niske incidencije moždanog udara u asimptomatskih bolesnika nameće se potreba da se identificiraju podskupine asimptomatskih bolesnika sa povećanim rizikom, da bi se opravdalo kirurško liječenje. Histološki sastav plaka karotidne arterije je upravo jedan od parametara koji bi mogli ukazivati na povećan rizik od moždanog udara. Uz prisutne određene histološke karakteristike plaka indikacija za operaciju se može donijeti i pri suženjima manjim od onih koja se sada smatraju indikacijom za operaciju. Pokazano je da krvarenje u plak predstavlja znak nestabilnosti plaka i pogoduje njegovu povećanju, te da predstavlja kritični trenutak kada stabilni plak prelazi u nestabilni (vulnerabilni) plak, tj. plak koji češće dovodi do nastanka moždanog udara. Idealna dijagnostička metoda morala bi pored točnog određivanja stupnja suženja, omogućiti i uvid u sastav plaka, tj. ukazati na eventualno prisustvo karakteristika plaka koje ga čine vulnerabilnim. Mi smo ovim radom pokazali da MSCT može otkriti plak kompliciran krvarenjem sa osjetljivošću od 100% i specifičnošću od 70,4% uz graničnu vrijednost tkivne gustoće od 33,8 HU. Drugim riječima, ni jedan plak kojemu je izmjerena gustoća veća od 33,8 HU nije bio kompliciran s krvarenjem. Prosječno suženje karotidnih arterija mjereno MSCT-om bilo je 82,6% (± 9,6%), dok je doplerom dobiveno prosječno suženje od 80,4% (±10,0%). (p=0,066878, Z= 1,832496, Wilcoxonov test ), što je potvrdilo visoku podudarnost nalaza MSCT-a i doplera kod utvrđivanja stupnja suženja karotidne arterije. Našli smo da je medijan tkivne gustoće AHA VIb tipa karotidnih plakova bio 14,7 HU (raspon -17,6 do 31,8), dok je medijan tkivne gustoće plakova nekompliciranih krvarenjem bio 54,3 HU (raspon -23,6 do 150). Korištenjem Mann-Whitney U testa dobila se statistički značajna razlika tkivne gustoće u navedene dvije skupine plakova (p=0,00003, U=97,00). Opisivanjem ultrazvučno dominantno mekanih i miješanih plakova kao jedne grupe dobila se osjetljivost ultrazvuka u otkrivanju krvarenja u plak od 100% i specifičnost od 48,1% . Time se UZV osjetljivošću izjednačava MSCT-u dok mu je specifičnost manja za 22,3% (apsolutna razlika) od one koju je pokazao MSCT. Bolji rezultati ultrazvuka zasigurno bi se dobili korištenjem specijaliziranog softwarea koji omogućuje detaljniju analizu, detaljniju klasifikaciju i kvantifikaciju dobivenih nalaza. Također postoji mogućnost da bi se korištenjem drugačije (detaljnije) klasifikacije dobili drugačiji rezultati. Zbog količine zračenja i izlaganja bolesnika kontrastnom sredstvu, MSCT iako prema ovoj studiji superiorniji u odnosu na UZV u otkrivanju krvarenja u plak, kao jedina pretraga vjerojatno nije pogodna metoda za praćenje dinamike progresije stupnja suženja niti za otkrivanje eventualne naknadne pojave krvarenja u plak U ovom radu MSCT je pokazao vrlo visoku osjetljivost i umjerenu specifičnost u otkrivanju krvarenja u karotidni plak. Plakovi sa tkivnom gustoćom iznad 33,8 HU nisu bili komplicirani krvarenjem u plak. Tehnička poboljšanja CT opreme vjerojatno će poboljšati specifičnost ove metode. Dopler i MSCT daju gotovo identične rezultate u mjerenju stupnja suženja karotidne arterije. UZV je pokazao visoku osjetljivost ali nisku specifičnost u otkrivanju krvarenja u plak. Primjenom odgovarajućeg softwarea vjerojatno bi se poboljšala specifičnost ultrazvuka u otkrivanju krvarenja u plak. English abstract Stroke is third leading cause of death and second leading cause of death among patients with cardiovascular diseases in developed countries. Atherosclerotic carotid plaque is the main cause of most strokes in people with carotid artery disease, by either causing embolisation or reducing blood flow through cerebral circulation. Carotid artery bifurcation and proximal segment of the internal carotid artery are the usual locations of the atherosclerotic carotid plaque. Large randomized trials showed benefit of carotid endarterectomy in symptomatic patients and to a lesser degree in asymptomatic patients. To justify carotid endarterectomy in asymptomatic patients, higher risk supgroups of asymptomatic patients should be identified. Histological content of the atherosclerotic plaque could be one of the indicators of its higher propensity for causing a stroke. When certain histological characteristics of the plaque are present, decision for carotid endarterectomy could be made even when degree of stenosis is lower than that currently considered to be an indication for carotid endarterectomy. It has been shown that occurence of hemorrhage within the atherosclerotic plaque represents a transition point when a stable plaque becomes unstable (vulnerable) plaque i.e. it becomes more prone to causing a neurologic event. The ideal diagnostic method should provide precise measurement of the degree of carotid artery stenosis, and in the same time it should be able to give information about histological content of the plaque thus detecting some characteristics of the plaque that make it vulnerable. With this study, we showed that MSCT could detect hemorrhage within the atherosclerotic carotid plaque with a sensitivity of 100% and specificity of 70,4% with a cut-off value of tissue density of 33.8 HU. We found that no plaque with tissue density greater then 33.8 HU was complicated with hemorrhage within the plaque. The mean carotid artery stenosis measured by MSCT and doppler was 82.6% (± 9.6%) and 80.4% (±10.0%), respectively (p=0.066878, Z=1.832496, Wilcoxon test). These results confirmed a high degree of concordance of MSCT and doppler in measuring degree of carotid artery stenosis. The median tissue density of the plaques AHA type VIb was 14.7 HU (range -17.6 to 31.8), and the median tissue density of the plaques not complicated with hemorrhage was 54.3 HU (range -23.6 to 31.8). The Mann-Whitney U test showed significant difference between these two groups (p=0.00003, U=97.00). If plaques presented on ultrasound as predominantly soft and those of combined content had been considered as a single group we reached specificity of ultrasound in detecting hemorrhage within the plaque of 100% and specificity of 48.1%. By doing so, we equalled sensitivity of ultrasound with sensitivity of MSCT but at the cost of the specificity that was 22.3% (absolute difference) less than specificity of MSCT. Better results of ultrasound analysis would probably be obtained by using a specialized software which enables more detailed analysis, more detalied classification and quantification of the results. Also, there is posibility that different results would be found if different (more detailed) classification was used. Although we showed that MSCT was superior to ultrasound in detecting hemorrhage within the plaque, it is probably not the ideal method for niether follow up of the progression of carotid artery stenosis nor for detecting later occurence of the hemorrhage within the plaque, due to the exposure of the patients to radiation and contrast agent. In this study MSCT showed very high level of sensitivity and moderate level of specificity in detecting hemorrhage within the atherosclerotic plaque. The plaques with tissue density above 33.8 HU were not complicated with hemorrhage. Techical advancement of the CT equipment will probablay increase the specificity of the method. MSCT and doppler showed almost identical results in measuring degree of the carotid artery stenosis. Ultrasound showed very high level of sensitivity and low level of specificity in detecting hemorrhage within the plaque. By using specialized software, the specificity of the ultrasound could probably be increased. Actions (login required)