В связи с тем, что МРТ становится доступнее и появляются небольшие аппараты МРТ для исследования одной конечности считаю актуальным пересмотр отношения к роли МРТ - как к более-менее рутинному (следующему после УЗДС, когда результаты УЗДС сомнительны) методу диагностики тромбоза глубоких вен голени.
Допустимо ли по Вашему мнению в клиниках травматологического профиля, не оснащённых аппаратами УЗДС с высокой проникающей и разрешающей способностью, но в арсенале которых есть МРТ (типа MSK Extreme) - использование этих аппаратов в качестве основного метода диагностики ТГВ?
Health Technol Assess. 2006 May;10(15):1-168, iii-iv.
Measurement of the clinical and cost-effectiveness of non-invasive diagnostic testing strategies for deep vein thrombosis.
Goodacre S, Sampson F, Stevenson M, Wailoo A, Sutton A, Thomas S, Locker T, Ryan A.
Medical Care Research Unit, University of Sheffield, UK.
Abstract
OBJECTIVES: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance. Also to identify practical diagnostic algorithms for DVT, and estimate the diagnostic accuracy, clinical effectiveness and cost-effectiveness of each. DATA SOURCES: Electronic databases (to April 2004). A postal survey of hospitals in the UK. REVIEW METHODS: Selected studies were assessed against validated criteria. A postal survey of hospitals in the UK was undertaken to describe current practice and availability of tests, and identify additional diagnostic algorithms. Pooled estimates of sensitivity, specificity and likelihood ratios were obtained for each test using random effects meta-analysis. The effect of study-level covariates was explored using random effects metaregression. A decision-analytic model was used to combine estimates from the meta-analysis and estimate the diagnostic performance of each algorithm in a theoretical population of outpatients with suspected DVT. The net benefit of using each algorithm was estimated from a health service perspective, using cost--utility analysis, assuming thresholds of willingness to pay of pound 20,000 and pound 30,000 per quality-adjusted life-year (QALY). The model was analysed probabilistically and cost-effectiveness acceptability curves were generated to reflect uncertainty in estimated cost-effectiveness. RESULTS: Individual clinical features are of limited diagnostic value, with most likelihood ratios being close to 1. Wells clinical probability score stratifies proximal, but not distal, DVT into high-, intermediate- and low-risk categories. Unstructured clinical assessment by experienced clinicians may have similar performance to Wells score. In patients with clinically suspected DVT, D-dimer has 91% sensitivity and 55% specificity for DVT, although performance varies substantially between assays and populations. D-dimer specificity is dependent on pretest clinical probability, being higher in patients with a low clinical probability of DVT. Plethysmography and rheography techniques have modest sensitivity for proximal DVT, poor sensitivity for distal DVT, and modest specificity.
Ultrasound has 94% sensitivity for proximal DVT, 64% sensitivity for distal DVT and 94% specificity. Computed tomography scanning has 95% sensitivity for all DVT (proximal and distal combined) and 97% specificity. Magnetic resonance imaging has 92% sensitivity for all DVT and 95% specificity. The diagnostic performance of all tests is worse in asymptomatic patients. The most cost-effective algorithm discharged patients with a low Wells score and negative D-dimer without further testing, and then used plethysmography alongside ultrasound, with venography in selected cases, to diagnose the remaining patients. However, the cost-effectiveness of this algorithm was dependent on assumptions of test independence being met and the ability to provide plethysmography at relatively low cost. Availability of plethysmography and venography is currently limited at most UK hospitals, so implementation would involve considerable reorganisation of services. Two algorithms were identified that offered high net benefit and would be feasible in most hospitals without substantial reorganisation of services. Both involved using a combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of pound 10,000 or pound 20,000 per QALY the optimal strategy involved discharging patients with a low or intermediate Wells score and negative D-dimer, ultrasound for those with a high score or positive D-dimer, and repeat scanning for those with positive D-dimer and a high Wells score, but negative initial scan. For thresholds of pound 30,000 or more a similar strategy, but involving repeat ultrasound for all those with a negative initial scan, was optimal. CONCLUSIONS: Diagnostic algorithms based on a combination of Wells score, D-dimer and ultrasound (with repeat if negative) are feasible at most UK hospitals and are among the most cost-effective. Use of repeat scanning depends on the threshold for willingness to pay for health gain. Further diagnostic testing for patients with a low Wells score and negative D-dimer is unlikely to represent a cost-effective use of resources. Recommendations for research include the evaluation of the costs and outcomes of using the optimal diagnostic algorithms in routine practice, the development and evaluation of algorithms appropriate for specific groups of patients with suspected DVT, such as intravenous drug abusers, pregnant patients and those with previous DVT, the evaluation of the role of plethysmography: interaction with other diagnostic tests, outcome of low-risk patients with negative plethysmography and measurement of the costs of providing plethysmography, and methodological research into the incorporation of meta-analytic data into decision-analytic modelling.
PMID: 16707072 [PubMed - indexed for MEDLINE]
Postgrad Med. 2010 Mar;122(2):66-73.
Diagnosing deep vein thrombosis. Somarouthu B, Abbara S, Kalva SP.
Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
bsomarouthu@partners.orgAbstract
In this article, we discuss the approach for diagnosing deep vein thrombosis (DVT) in different patient populations. Clinical features and probability assessment guide further diagnostic tests. D-dimer testing is used as screening test; however, duplex ultrasound remains the primary confirmatory test. Computed tomography and magnetic resonance imaging are used only in select patient populations, such as when ultrasound results are equivocal, in patients suspected of central venous DVT, or as a part of combined protocol for diagnosis of pulmonary embolism. Contrast phlebography and plethysmography do not have much of a role during routine diagnosis of DVT.
PMID: 20203457 [PubMed - indexed for MEDLINE]
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Мощность его ниже чем у стационарных сканеров, но это не мощность излучения, а мощность центрального и графического процессоров, объем оперативной памяти и др. особенности его "харда". На глубину проникновения луча эти параметры никоим образом не влияют. Если пациент очень тучный, можно воспользоваться конвексным датчиком, обладающим меньшей частотой излучения и соответственно большим проникновением в ткани. Что такое дистальный ТГВ? Тромбоз ЗББВ? ЗББВ - главный и самый мощный коллектор оттока крови от стопы, они - составная и неотделимая часть венозной помпы, там высокий кровоток и самостоятельно, так сами по себе они не затромбируются. Тромбоз чаще всего изначально происходит в мышечных синусах голени, поэтому начинается поиск ТГВ именно от туда - а здесь достаточно лоджик-бука за 600 тысяч рублей (вместе с линейным датчиком). МРТ малым аппаратом для одной ноги несомненно даст интересную информацию, лично я с такими аппаратами не встречался и было бы интересно посмотреть как они выглядят и работают. Но для диагностики ТГВ именно в травматологии этот метод будет малопригоден, опять-таки из-за металлоконструкций. ИМХО.
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