| Spontaneous isolated superior mesenteric artery dissection(SISMAD)is a rare disease that occurs spontaneously and involves only the superior mesenteric artery.Acute abdominal pain is the most common clinical symptom.If the correct diagnosis can not be made in time,it may lead to large areas of intestinal ischemia and necrosis,and even death in some serious cases.However,the clinical symptoms and biochemical tests are lack of specificity,and it is easy missed diagnossis or even misdiagnosis.A simple,accurate and reproducible imaging examination method is urgently needed to diagnose and evaluate the curative effect dynamically.At present the imaging diagnosis of SISMAD mainly focuses on CT angiography(CTA)or digital subtraction angiography(DSA).CTA has the advantages of relatively noninvasive,safe,fast and accurate.It is an important imaging examination method for the diagnosis,prognosis evaluation and follow-up of SISMAD.However,it has radiation,contrast media allergy and other contraindications,such as diabetic patients taking dimethylbiguanide and patients with renal insufficiency.In addition,it is not suitable for multiple examinations in a short period of time.Ultrasound has the advantages of convenience,rapidity,low cost and no radiation,which is widely used in the diagnosis and follow-up of clinical diseases.Previous attempts at ultrasound examination failed due to poor quality of ultrasound machines and insufficient understanding of the disease.The ultrasound probe can make the blood vessel position relatively shallow by squeezing the abdominal wall,and the ultrasonic image quality can be clearly displayed.However,ultrasound has some limitations,such as excessive attenuation of ultrasound beam by adipose tissue in obese patients and secondary intestinal obstruction,which interferes with ultrasonic beam examination and affects the accurate diagnosis of SISMAD.With the rapid development of ultrasound technology,cardiac probe tissue harmonic imaging and contrast-enhanced ultrasound technology,ultrasound imaging effect is getting better and better.Tissue harmonic imaging(THI)is a kind of second harmonic amplification imaging with transmitting low-frequency fundamental wave and receiving double fundamental frequency.It can significantly improve the resolution and contrast of two-dimensional image,and improve the display ability of deep tissue.Contrast-enhanced ultrasound mainly uses contrast agent to enhance the backscatter of blood,and the contrast agent is accompanied by blood flow,so it reduces the occurrence of artifacts and greatly improves the resolution,sensitivity and specificity of ultrasound diagnosis.At present,there are few reports on the clinical application of ultrasound harmonic imaging and contrast-enhanced ultrasound for SISMAD.The purpose of this study was to investigate the specificity and dynamic evaluation value of ultrasound harmonic imaging and contrast-enhanced ultrasound in the diagnosis of SISMAD.PART I:Research on the clinical diagnosis of contrast-enhanced ultrasound and harmonic ultrasound imaging in spontaneous isolated superior mesenteric artery dissectionObjective:To investigate the specificity of harmonic imaging and contrast-enhanced ultrasound in the diagnosis of SISMAD.Methods:From May 2014 to July 2019,33 patients in Shandong Provincial Hospital with SISMAD were included.Two patients underwent ultrasound harmonic imaging without CTA,including 1 diabetic patient who took metformin and 1 patient with renal insufficiency.The remaining 31 patients underwent harmonic ultrasound imaging,contrast-enhanced ultrasound and CTA.1?Ultrasound harmonic imaging and contrast-enhanced ultrasound in the morphology diagnosis of SISMAD.Ultrasonic harmonic imaging,contrast-enhanced ultrasound and CTA were used to measure the distance from the rupture of SISMAD to the upper edge of superior mesenteric artery orifice,diameter,area,diameter stenosis rate and area stenosis rate of the narrowest true lumen in 31 cases three times respectively,and the average value was taken.According to the classification of isolated superior mesenteric artery dissection by Yun et al.in 2009,31 cases were divided into three types:Type ?,Type ?,and Type?.Type ? can be divided into two subtypes:Type ? A and Type ? B.The accuracy,sensitivity and specificity of ultrasound harmonic imaging and contrast-enhanced ultrasound were statistically analyzed comparing with the CTA subtypes.2.The hemodynamics of spontaneous isolated superior mesenteric artery dissection was evaluated by harmonic imaging and contrast-enhanced ultrasound.In order to better reflect the degree of true lumen stenosis and predict the clinical treatment effect,based on the different degree of true lumen stenosis monitored by Ultrasound Hemodynamics,a new classification was proposed:type A,type B and type C.type A was further divided into two subtypes A1 and A2.Type A:true lumen stenosis,but the peak flow velocity at the narrowest part of true lumen is less than 275 cm/s.Type A can be divided into two subtypes:A1 and A2:Type A1:the peak flow velocity at the narrowest part of true cavity is less than 180 cm/s;Type A2:the peak flow velocity at the narrowest part of true cavity is more than 180 cm/s;Type B:true lumen is obviously compressed,the peak flow velocity at the narrowest part of true lumen is more than 275 cm/s;type C both true and false lumens are occluded and no blood flow signal is found.Statistical methods:Paired sample t-test was performed on the measured values of ultrasound harmonic imaging and contrast-enhanced ultrasound and CTA measurement of superior mesenteric artery dissection.Kappa test was used to evaluate the consistency of ultrasound and CTA classification results.When kappa ? 0.75,the consistency was good and the reliability was high;0.75>kappa?0.4 was the general consistency;kappa<0.4 was the poor consistency.Results:1.Ultrasound harmonic imaging,contrast-enhanced ultrasound and CTA have high consistency in the morphological imaging diagnosis of SISMAD.Ultrasound harmonic imaging and contrast-enhanced ultrasound in the diagnosis of SISMAD classification(Yun classification)was compared with CTA(31 cases).CTA diagnostic classification:9 cases of type ? dissection,13 cases of type ?A,6 cases of type ? B,3 cases of type ?;ultrasonic diagnosis classification:8 cases of type ? dissection,12 cases of type ?A,7 cases of type ?B,and 4 cases of type ?.One case of type ? dissection was mistaken as type ?B due to the formation of false lumen thrombosis around the intimal outlet;one case of type ?A was mistakenly considered as type ? because of the severe stenosis of the true lumen,which was close to occlusion and the blood flow velocity was extremely slow.Color Doppler ultrasound did not detect obvious blood flow,so it was mistaken as type ?,but contrast-enhanced ultrasound could clearly show the true lumen linear signal.The accuracy,sensitivity and specificity of ultrasonography were 88.89%,100%,96.77%,92.31%,100%,96.77%for type ?A,100%,96.77%for type ?B,and 100%,96.43%and 95.77%for type ? dissection compared with CTA.The consistency test results of ultrasound and CTA showed that the kappa=0.817,which was high.The distance from the breach to the upper edge of superior mesenteric artery orifice,the true lumen diameter,the stenosis rate of true lumen diameter,the true lumen area and the stenosis rate of true lumen area were measured by harmonic imaging,contrast-enhanced ultrasound and CTA.There were no statistically significant differences in the breach to the upper edge of superior mesenteric artery orifice,the true lumen diameter,the stenosis rate of true lumen diameter,the true lumen area and the stenosis rate of true lumen area between ultrasound and CTA(P>0.05).2.The hemodynamic study of ultrasound harmonic imaging can better reflect the true lumen stenosis degree of SISMAD and predict the clinical curative effect.31 cases of isolated superior mesenteric artery dissection were classified as type A1 in 8 cases,type A2 in 12 cases,type B in 8 cases and type C in 3 cases.Type A(64.52%):true lumen stenosis,but the peak flow velocity at the narrowest part of true lumen is less than 275 cm/s.Type A can be divided into two subtypes:A1 and A2:Type A1(25.81%):the peak flow velocity at the narrowest part of true cavity is less than 180 cm/s;Type A2(38.71%):the peak flow velocity at the narrowest part of true cavity is more than 180 cm/s;Type B(25.81%):true lumen is obviously compressed,the peak flow velocity at the narrowest part of true lumen is more than 275 cm/s;type C(9.68%):both true and false lumens are occluded and no blood flow signal is foundConclusion:1.Ultrasound harmonic imaging,contrast-enhanced ultrasound and CTA have a high degree of consistency in the imaging diagnosis of spontaneous isolated superior mesenteric artery dissection.2.The study of hemodynamics of spontaneous isolated superior mesenteric artery dissection by harmonic imaging and contrast-enhanced ultrasound can monitor the degree of true lumen stenosis,and the new classification can provide objective imaging basis for clinical treatment.PART II:Dynamic evaluation of curative effect of spontaneous isolated superior mesenteric artery dissection by harmonic ultrasound imagingObjective:To explore the application value of ultrasonic harmonic imaging in the dynamic evaluation of the curative effect of SISMADMethods:33 patients with spontaneous isolated superior mesenteric artery dissection who were treated in Shandong provincial hospital from May 2014 to July 2019 were enrolled in this study.Two patients underwent ultrasound harmonic imaging without CTA,including 1 diabetic patient who took metformin and 1 patient with renal insufficiency.The remaining 31 patients underwent harmonic ultrasound imaging,contrast-enhanced ultrasound and CTA.Ultrasonic harmonic imaging was used to evaluate the morphological imaging diagnosis of spontaneous isolated superior mesenteric artery dissection.Dynamic follow-up observation with ultrasound harmonic imaging in the classification of spontaneous isolated superior mesenteric artery dissection was carried out in 1st,6th,12th and 24th months respectively.The effect of conservative treatment,the evaluation of stent after endovascular stent placement and the recanalization of superior mesenteric artery lumen after open surgery were evaluated.Ultrasound harmonic imaging was used to monitor the hemodynamics of spontaneous isolated superior mesenteric artery dissection.Results:1.Morphological evaluation of the curative effect of spontaneous isolated superior mesenteric artery dissection by ultrasonic harmonic imaging.The dynamic evaluation of curative effect of 33 patients with isolated superior mesenteric artery dissection was carried out at 1st,6th,12 thand 24th months respectively.2(6.06%)patients had a change in classification.One case changed from type ?B to type ?A at the first month,and one case changed from type ?A to type ? at the sixth month.Ultrasonic harmonic imaging can accurately diagnose the type changes of spontaneous isolated superior mesenteric artery dissection.Ultrasound harmonic imaging was used to evaluate the curative effect of 33 cases of isolated superior mesenteric artery dissection.Among them,11 cases(33.33%)underwent stent placement in superior mesenteric artery.The shape of stent was normal without distortion.l(3.03%)had thrombosis in the middle of stent,and the remaining stent was unobstructed;2(6.06%)had superior mesenteric artery embolectomy and endarterectomy.The lumen was unobstructed in 1 case(3.03%),and 1(3.03%)died of infection due to short bowel syndrome one month after operation.The remaining 20 patients adopted conservative treatment,and the clinical symptoms were relieved.2.Hemodynamic monitoring of spontaneous isolated superior mesenteric artery dissection by harmonic ultrasound imaging33 cases of SISMAD were classified as follows:type A1 9 cases,type A2 13 cases,type B 8 cases and type C 3 cases.9 cases(27.27%)of type A1 dissection had no increase of blood flow velocity and no restenosis of true lumen during follow-up.During the dynamic evaluation of curative effect,3 cases(9.09%)of type A2 dissection patients developed abdominal pain symptoms and aggravated.Ultrasound harmonic imaging showed that the true lumen became narrower,with the true lumen stenosis rates of 75%,78%and 85%,respectively.The blood flow velocity of the local true cavity was significantly increased,and the peak velocity was 310cm/s,321cm/s and 404cm/s,respectively.During the follow-up period,the treatment plans were changed and endovascular stent placements were given clinically.The other 10 cases(30.3%)of type A2 dissection showed no increase in blood flow velocity and no restenosis of true lumen during follow-up.19 cases(57.58%)of type A dissection had enlarged true lumenafter absorption of thrombus in the false lumen,and decreased peak velocity at narrowest true lumen(165.8±41.94 cm/s).8 cases(24.24%)of type B dissection had persistent abdominal pain and severe true lumen stenosis after 48 hours of conservative treatment.There were 3 cases(9.09%)of type C,of which 1 case was treated with endoluminal stent placement and 2 cases underwent open surgery(superior mesenteric artery thrombectomy and endarterectomy).One patient(3.03%)died of short bowel syndrome and abdominal infection one month after operation.Conclusion1:According to the clinical needs,ultrasound harmonic imaging can evaluate the curative effect of spontaneous isolated superior mesenteric artery dissection in real time and accurately.It is convenient,fast and feasible.2:Ultrasound harmonic imaging based on hemodynamics can monitor true lumen stenosis and blood flow velocity changes,which provideobjective imaging evidence clinical treatment options and evaluation. |
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