Lower limb deep venous thrombus magnetic resonance imaging method and device

Abstract

The invention provides a lower limb deep venous thrombus magnetic resonance imaging method and device. On the premise that no contrast media are used, injuries to a patient are avoided, and meanwhile the imaging effect is improved. The method includes the steps that blood flow signals of lower limb deep veins are suppressed, blood vessel wall and thrombus signals of the lower limb deep veins are retained, and preprocessed signals of the lower limb deep veins are obtained; the preprocessed signals of the lower limb deep veins are sampled through a variable-turning-angle spin echo sequence or a fast small-angle gradient echo sequence; according to sampled data, a lower limb deep venous thrombus magnetic resonance image is acquired. By means of the technical scheme, on one hand, blood vessel walls, blood flow and thrombi of the lower limb deep veins can be accurately differentiated, and whether thrombi exist in blood vessels or not can be visually displayed; on the other hand, the lower limb deep venous thrombus magnetic resonance image obtained through the method and device can display whether thrombi exist in the lower limb deep veins or not and the distribution positions of the thrombi, the thrombi can be preliminarily staged, and practical and effective information is provided for clinical treatment.

Description

technical field [0001] The invention belongs to the field of medical imaging, in particular to a magnetic resonance imaging method and device for deep vein thrombosis of lower extremities. Background technique [0002] At present, there are four types of imaging techniques that can be used for the examination of deep vein thrombosis (Deep Vein Thrombosis, DVT) of the lower extremities, including venous angiography (Digital Subtraction Angiography, DSA), ultrasound, CT, and magnetic resonance imaging. These four types of methods have their own advantages and disadvantages. For example, DSA can accurately determine the presence or absence of thrombus and its distribution range, but this method is invasive and only used in the process of interventional treatment; although ultrasound is noninvasive, it is convenient and simple. However, it relies too much on the doctor's technique and experience, and this technology can only determine the distribution range of thrombus, but cann...

AI Technical Summary

Problems solved by technology

[0003] Magnetic resonance imaging techniques commonly used in the clinical diagnosis of DVT mainly include enhanced magnetic resonance angiography (Contrast Enhanced Magnetic Resonance Venography, CE-MRV), balanced steady-state free precession imaging (balanced Steady-state Free Precession, bSSFP) and inversion gradient echo-based imaging. There are three magnetic resonance direct thrombus imaging techniques (Magnetic Resonance Direct Thrombus Imaging, MRDTI), among which CE-MRV is often used to determine the presence or absence and distribution of thrombus, and can preliminarily estimate the thrombus age based on the enhanced performance of thrombus and vessel wall, but CE-MRV examination needs to accurately estimate the circulation time of the target blood vessel, and the scanning operation is difficult. At the same time, the use of contrast agent not only increases the examination cost, but also cannot be used in patients with severe renal insufficiency and pregnant women. The natural brightness of bSSFP technology The blood effect makes the blood flow in the lumen of the vessel show high signal and the thrombus shows low signal without using contrast agent. In terms of judging whether the vessel is occluded, the effect is similar to CE-MRV, but bSSFP technology can only be used for DVT The rapid screening of thrombus can not clearly show the size of thrombus, and cannot judge the age of thrombus. It is also susceptible to banding artifacts caused by the inhomogeneity of the main magnetic field of the magnetic resonance system. As for MRDTI, it is a T1-weighted technique. Gradient echo sequence, which utilizes the unique paramagnetic properties of methemoglobin in subacute thrombus to directly image the thrombus, has high specificity and sensitivity, but MRDTI technology relies too much on methemoglobin content to shorten T1 relaxation time, so that the thrombus appears as a bright signal in the image, so only the thrombus with high methemoglobin content (acute → subacute) or subacute phase can be diagnosed, while the hyperacute and subacute thrombus with low methemoglobin content can be diagnosed. chronic thrombosis powerlessness

Recently, a magnetic resonance vessel wall imaging technique was proposed to achieve clinical examination and diagnosis of DVT, but this technique uses a three-dimensional fast spin-echo sequence, which has very limited suppression effect on blood flow signals and cannot completely suppress venous vessels. The blood flow signal in the cavity makes the imaging result easily polluted by the blood flow signal, and it is difficult to accurately distinguish the vessel wall, blood flow and thrombus

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