Multidetector CT and CT angiography in mesenteric ischemia

Purpose

To evaluate the role of 64-multidetector CT in assessment of mesenteric vascular ischemia in clinically suspected patients.

Patients and methods

This study included 38 patients during period from October 2009 to October 2011. The patients age ranged from 38 to 72 year old (mean age was 57 ± 11.2 years). All cases met the criteria of acute non traumatic (28 patients) or chronic abdominal pain (10 patients) and suspected mesenteric vascular ischemia. All 38 cases were evaluated in surgery department, then underwent CT of the abdomen and pelvis & CTA by using 64 multislice GE light speed VCT. MDCT& CT angiographic findings were correlated with surgical findings in acute mesenteric ischemia (AMI) cases & conventional angiography in chronic mesenteric ischemia (CMI) cases.

Results

MDCT findings alone were nonspecific for detection of MI. The sensitivity, specificity& accuracy of CTA in diagnosis of AMI after surgical confirmation were 96%, 66.6% & 92.8% respectively, while in CMI the sensitivity, specificity & accuracy were 88.8%, 100%, 90% respectively, after confirmation by conventional angiography.

Conclusion

CTA scan appears to be an excellent tool to find out and localize cases of AMI rather than in CMI cases.     

Multidetector CT angiography in the evaluation of acute mesenteric ischemia

The aim of this study was to determine the accuracy of multidetector row CT angiography in the diagnosis of acute mesenteric ischemia. Ninety-three consecutive studies on 91 patients with clinically suspected acute mesenteric ischemia underwent abdominal CT angiography as the first, and usually the sole, diagnostic procedure. CT was performed with a multidetector 16-row CT system from the level of the diaphragm to the pelvis in two phases: early arterial and late portal phase. CT examinations were reviewed by the duty radiologist. Final diagnosis was established by a senior radiologist. CTA was diagnostic in 92 studies. Mesenteric ischemia was diagnosed in 18 patients, 14 of them were of the thromboembolic type and four from the nonocclusive type. Positive CTA findings were confirmed by surgery in 13 patients and by clinical follow-up in three cases. Other reasons for abdominal pain were diagnosed by CT in 38 patients out of the remaining 74. There were two false positive and two false negative CT results, resulting in an overall accuracy of 95.6%. Multidetector CT angiography is a fast and accurate investigation for the diagnosis of acute mesenteric ischemia and in most cases can be used as the sole diagnostic procedure.     

Evaluating mesenteric ischemia with multidetector-row CT angiography

Multidetector-row computed tomographic (MDCT) angiography is an established non-invasive imaging modality to evaluate the mesenteric vasculature. It has an important role in diagnostic algorithms for assessment of suspected acute and chronic mesenteric ischemia. Clinical success for synchronizing a MDCT volumetric acquisition with a bolus of contrast medium and also for depicting vascular pathology with high accuracy relies on implementing several key principles. This can be more challenging with advanced generation MDCT scanners. This article reviews the technical principles fundamental to evaluating the mesenteric vasculature with MDCT angiography. An overview of clinical application is also presented.     

Multidetector CT angiography in Takayasu arteritis

Objective

To analyse the spectrum of Takayasu's arteritis (TA) on multidetector CT angiography (MDCTA).

Materials and methods

A retrospective analysis of the MDCTA findings was performed on 15 patients clinically diagnosed as Takayasu's arteritis. The spectrum and incidence of imaging findings on CTA were compared to studies in literature on catheter angiography in Takayasu's arteritis. Laboratory parameters were available in nine patients. The disease was considered active if erythrocyte sedimentation rate (ESR) levels were elevated and ‘C’ reactive protein (CRP) was positive. An attempt was made to correlate disease activity with the imaging findings.

Results

Ascending aorta, arch of aorta and descending thoracic aorta were involved in 14 out of 15 (93%) patients. The wall thickness varied between 1 and 10 mm with maximal involvement in arch and descending thoracic aorta. Major neck vessels were involved in 11 (73%) patients with most pronounced changes seen in the brachiocephalic trunk, left common carotid artery (CCA) and left subclavian artery (SCA). Abdominal aorta and its branches were involved in all the 11 (100%) patients in whom abdominal CTA was performed. Celiac axis and SMA were involved in 10 (91%) and seven (64%) patients, respectively while renal artery stenosis was present in five (45%) patients. In six patients, ESR was elevated and CRP was positive indicating active disease. All patients in whom the laboratory parameters were available showed mural thickening in the aorta and at least one of the neck vessels except for one patient with inactive disease who had aortic mural thickening only.

Conclusion

MDCTA provides information about both the vessel wall and lumen in patients with Takayasu's disease.     

Non-occlusive mesenteric ischemia: etiology, diagnosis, and interventional therapy

Non-occlusive mesenteric ischemia (NOMI) compromises all forms of mesenteric ischemia with patent mesenteric arteries. It generally affects patients over 50 years of age suffering from myocardial infarction, congestive heart failure, aortic insufficiency, renal or hepatic disease and patients following cardiac surgery. Non-occlusive disease accounts for 20-30% of all cases of acute mesenteric ischemia with a mortality rate of the order of 50%. Acute abdominal pain may be the only early presenting symptom of mesenteric ischemia. Non-invasive imaging modalities, such as CT, MRI, and ultrasound, are able to evaluate the aorta and the origins of splanchnic arteries. Despite the technical evolution of those methods, selective angiography of mesenteric arteries is still the gold standard in diagnosing peripheral splanchnic vessel disease. In early non-occlusive mesenteric ischemia, as opposed to occlusive disease, there is no surgical therapy. It is known that mesenteric vasospasm persists even after correction of the precipitating event. Vasospasm frequently responds to direct intra-arterial vasodilator therapy, which is the only treatment that has been shown to be effective.     

Usefulness of multidetector-row CT (MDCT) for the diagnosis of non-occlusive mesenteric ischemia (NOMI): Assessment of morphology and diameter of the superior mesenteric artery (SMA) on multi-planar reconstructed (MPR) images

Objective

The purpose of this study was to assess the efficacy of multidetector-row CT (MDCT) for the diagnosis of non-occlusive mesenteric ischemia (NOMI) by analyzing morphology and diameter of superior mesenteric artery (SMA). We assessed whether MDCT was as useful as angiography for the diagnosis of NOMI.

Materials and methods

Four patients who were diagnosed with NOMI were retrospectively analyzed. All patients had 8-row MDCT followed by laparotomy. Two of them underwent angiography after MDCT. The morphology and diameter of SMA of these cases was analyzed on multi-planar reconstructed (MPR) images. The mean diameter of SMA of NOMI cases was compared to that of 13 control cases.

Results

MPR images of all NOMI cases showed irregular narrowing of the SMA, spasm of the arcades of SMA, and poor demonstration of intramural vessels. MPR images of two patients who had angiography were concordant with their angiograms. The mean diameter of SMA of NOMI patients was 3.4 ± 1.1 mm, which was statistically smaller than that of 13 control patients, 6.0 ± 1.5 mm (P < 0.05, Wilcoxon rank sum tests).

Conclusion

Angiography has been recognized essential for the diagnosis of NOMI. This study shows the possibility of MDCT to be an equivalently useful modality compared to angiography for the diagnosis of NOMI by interpreting morphologic appearance and diameter of SMA. Introduction of MDCT in the decision tree of NOMI treatment may bring the benefit of prompt diagnosis and subsequent early and efficient initiation of therapy, which may improve the mortality.     

Limitations of angiography for mesenteric ischemia caused by midgut carcinoid tumors

Mesenteric ischemia associated with carcinoid tumors often presents with nonspecific abdominal pain and is usually due to mesenteric branch artery occlusion caused by elastic vascular sclerosis. Mesenteric ischemia was defined by the operative findings of cyanosis or infarction. Eleven patients with intraabdominal metastatic carcinoid tumor were evaluated by angiography. Angiographic narrowing and occlusion of multiple peripheral jejunal and ileal intramesenteric branch arteries was present in 3 patients with mesenteric ischemia, but also occurred in 5 of 8 patients without mesenteric ischemia. Other angiographic abnormalities included staining of the primary tumor (5) or metastases (6), tenting of small mesenteric vessels (5), and occlusion of draining mesenteric veins (2). We conclude that in patients with midgut carcinoid tumors, angiographic narrowing and occlusion of peripheral mesenteric arteries most likely represents elastic vascular sclerosis, is indicative of mesenteric invasions of tumor, but correlates poorly with the presence of ischemia in the subtended bowel. Alternatively, a normal selective arteriogram should exclude mesenteric ischemia as the cause of abnormal pain.     

Mechanical Thrombectomy Using the Solitaire AB Device for Acute Embolic Mesenteric Ischemia

Purpose

To review preliminary efficacy and safety outcomes of mechanical thrombectomy using the Solitaire AB device combined with thromboaspiration for treatment of acute embolic occlusion of the superior mesenteric artery (SMA).

慢性系膜动脉缺血的腔内治疗:我们理解了多少

收集并总结慢性系膜动脉缺血腔内治疗的临床资料.以"系膜动脉缺血"、"球囊血管成形"、"系膜动脉支架"和"肠坏死"为主题词经Medline搜索相关文献,对腔内治疗大于5例的文献进行分析.分析16个系列研究共328例患者.所有治疗指征都是症状型系膜动脉狭窄.治疗成功率91%.75%患者症状消失且不需要再次干预治疗.28%患者随访中发现再狭窄.9%出现了并发症,包括夹层、远端栓塞、中转为传统手术、感染及穿刺点部位血栓和出血等.30 d病死率3%.腔内治疗系膜动脉狭窄或闭塞安全、有效,支架植入有更高的技术成功率.但即使是腔内治疗非常成功,依然有三分之一的患者可能出现再狭窄.     

Acute mesenteric ischemia: recent advances in diagnosis and endovascular therapy

Acute mesenteric ischemia is a complex disorder associated with high morbidity and mortality. Recent advances in interventional radiology techniques have provided a variety of less invasive, endovascular approaches to the treatment of acute mesenteric ischemia. This article reviews the etiologies and imaging findings of acute mesenteric ischemia and describes evolving endovascular therapies.     

多层螺旋CT评价急性肠系膜缺血严重性的实验研究

目的：建立犬急性肠系膜缺血（AMI）的动物模型,探讨MSCT表现与缺血时间、缺血程度的相关性,并与病理对照,评价MSCT对AMI的诊断价值。材料和方法：健康成年杂种犬18只,体重15～20kg,雌雄不限。应用Seldinger技术经犬右股动脉穿刺,以无水乙醇栓塞肠系膜上动脉远端的空肠及回肠分支,建立犬AMI模型。将18只AMI模型犬于栓塞术前、术后1～6h行MSCT平扫及双期增强扫描,每隔1h随机处死3只,取缺血段肠标本。结果：18只实验犬均成功建立AMI模型。缺血不同时段的CT表现不同,早期表现为肠系膜水肿、肠腔扩张、肠壁增厚,后期出现腹水、肠壁积气及门静脉积气。术后异常肠壁的增强幅度均小于术前,3～6h组大体和组织学观察可见肠壁缺血的改变。结论：多层螺旋CT可明确诊断肠系膜缺血,且随着缺血时间的延长CT表现逐渐增多,其增强幅度与其缺血时间及缺血程度呈负相关。     

Mesenteric CT angiography: a discussion of techniques and selected applications

Sixty-four slice MDCT with advanced three-dimensional (3D) visualization software provides a unique opportunity for noninvasive evaluation of the mesenteric vasculature. Although standard axial computed tomography (CT) scanning has always allowed identification of the mesenteric arteries and veins, it is limited in its ability to adequately image small branches and complex anatomy. However, the submillimeter collimation possible with 64-slice CT scanners now allows the acquisition of true isotropic data and therefore high spatial resolution is now maintained in any imaging plane. This ability to visualize the mesenteric vasculature in real-time using 3D rendering and multiplanar reconstruction is crucial for comprehensive review of the complex mesenteric vessels. In this article, we discuss CT scanning protocols and 3D imaging techniques that can be utilized for CT angiography of the mesenteric vessels. Additionally, we will discuss several key conditions that illustrate the value of 3D imaging over standard axial images in mesenteric CT angiography.     

Post traumatic arterial occlusive mesenteric ischemia: a rare case report

Mesenteric ischemia is an uncommon condition with very high mortality rates characterized by inadequate blood supply, inflammatory injury, and subsequent necrosis of the bowel wall. Acute arterial mesenteric ischemia is usually caused by cardiac emboli, atherosclerotic vascular disease, aortic aneurysm, or dissection. We report a case of a 60-year-old male who presented to the accident and emergency department complaining of abdominal pain following blunt abdominal trauma. An urgent contrast enhanced computed tomography scan demonstrated superior mesenteric artery thrombosis with ischemic small bowel. Surgical intervention was carried out with resection of the necrotic bowel followed by anastomosis. Acute occlusive mesenteric ischemia needs to be considered in cases of blunt trauma presenting with abdominal pain. Proper early diagnosis and management is essential as it carries a high risk of morbidity and mortality.     

Multidetector CT chest with bronchial and pulmonary angiography determining causes,site and vascular origin of bleeding in patients with hemoptysis

Objective

To assess the role of MDCT chest with bronchial and pulmonary angiography in determining the cause, site of bleeding, and its vascular origin in patients presenting with hemoptysis.

Materials and methods

Fifty patients suffering from hemoptysis were evaluated by MDCT with bronchial and pulmonary angiographic techniques.

Results

MDCT chest with angiography revealed the cause in 84% of cases, the site and vascular origin in 76% of cases presenting with hemoptysis.

Conclusion

MDCT of the chest with bronchial and pulmonary angiography is considered a primary noninvasive imaging modality in the evaluation of patients with hemoptysis. It also serves as a guide for other diagnostic or therapeutic procedures.     

急性非闭塞性肠系膜血管缺血的诊断和介入治疗

目的探讨选择性肠系膜上动脉造影,经肠系膜上动脉持续灌注罂粟碱在诊断和治疗急性非闭塞性肠系膜血管缺血(NOMI)的价值。方法回顾分析从1999年8月到2005年3月经选择性肠系膜上动脉造影确诊,并行介入诊疗的18例NOMI。明确NOMI诊断后即行经导管肠系膜上动脉灌注罂粟碱治疗。结果本组18例NOMI中15例患者治愈;3例有效,介入治疗后腹痛减轻,但仍有局限性的腹膜刺激征,转外科行肠切除治愈;1例10d后死于严重肺部感染导致的呼吸衰竭。结论选择性肠系膜上动脉造影持续经导管肠系膜上动脉灌注罂粟碱是NOMI有效的诊断和治疗方法。     

CT angiographic demonstration of a mesenteric vessel "whirlpool" in intestinal malrotation and midgut volvulus: a case report

Although the color Doppler ultrasonography diagnosis of intestinal malrotation with midgut volvulus, based on the typical "whirlpool" appearance of the mesenteric vascular structures is well-defined in the peer-reviewed literature, the combination of both the angiographic illustration of these findings and the contemporary state-of-the-art imaging techniques is lacking. We report the digital subtraction angiography and multidetector computed tomography angiography findings of a 37-year-old male with intestinal malrotation.     

Incidental findings on cardiac computed tomography. Should we look?

Although the intent of cardiac computed tomographic angiography (CTA) is to visualize the coronary, aortic, and cardiac structures, portions of noncardiac structures are visible on the scan. Because cardiac CT scanning is primarily obtained with a small field of view (to maximize coronary visualization with highest spatial resolution), some have argued that the scans should be secondarily reconstructed to further evaluate portions of the lung, breast, and bone. The suggested benefits of a routine radiologist overread of the extracardiac structures for incidental findings have not been scientifically validated and mostly come from anecdotal experiences. The same anecdotal arguments were used to support body scanning; the idea that complete visualization of all structures will lead to earlier cancer detection and therefore better outcomes. Every center that has ever offered body scanning can show a case of early detection of lung cancer, renal cancer, and colon cancer, thus proving their efficacy. However, body scanning has been uniformly discouraged, most strongly by the American College of Radiology and other professional organizations, because of the high number of false-positive findings, low ratio of true positives to false positives, high follow-up costs, and increased anxiety, all without proof of improvement in outcomes. Similar arguments were also made for routine chest x-rays in smokers, until studies showed that earlier detection of lung masses did not lead to improvement in outcomes. Preliminary studies are showing that enlarging the field for CTA scans to look for incidental findings will suffer the same fate as body scanning and chest x-rays, as another form of screening that cannot be medicolegally justified because of severely high false-positive rates and no improvement in outcomes. Until data are available to the opposite, we should use our good judgment and restraint and not perform large-field reconstructions for the explicit purpose of screening.     

Assessment of ureteral obstruction in patients with compromised renal function: Value of Curved Planar Reformations in MDCT

Objective

To evaluate the usefulness of MDCT using a curved planar reformation technique for the noninvasive assessment of the causes and level of ureteral obstruction in patients with compromised renal function.

Patients and methods

Between January 2012 and February 2013, 50 patients with clinical and sonographic manifestations of ureteral obstruction underwent non-contrast multidetector CT (MDCT) using a 16-slice machine. A total of 65 ureters were examined. Curved planar reformation images were performed to display the entire course of ureters in the same image. All patients had renal impairment with serum creatinine greater than 2.0 mg/dl. The gold standard for diagnosis of the cause of obstruction was ureteroscopy and/or open surgery. The sensitivity, specificity and overall accuracy of MDCT using curved planar reformation in the diagnosis of ureteral obstruction were calculated in comparison with the gold standard.

Results

A total of 65 ureters were examined (35 unilateral, 15 bilateral). The most common cause of ureteric obstruction was ureteric stone representing 27/65 (41.5%), followed by ureteric stricture representing 23/65 (35.4%). The lower third was the most affected in our study, it was encountered in 38/65 ureters (58.46%). The total sensitivity, specificity and accuracy of CPR for the cause of the ureteric obstruction were 98.5%, 98.5% and 97.8%, respectively (P value >0.05). CPR also was more sensitive and accurate for the level of ureteral obstruction with a total sensitivity of 100% and accuracy of 100% (P value >0.001).

Conclusion

Curved planar reformation MDCT is a useful noninvasive technique which is accurate in diagnosing the cause and level of ureteral obstruction in patients with compromised renal functions and is helpful for planning the therapeutic management of such patients.     

Potential Influence of Acute CT on Inpatient Costs in Patients with Ischemic Stroke

RATIONALE AND OBJECTIVES: Patients presenting with ischemic brain symptoms have widely variable outcomes dependent to some degree on the pathologic basis of their stroke syndrome. The purpose of this study was to determine the cost implications of the emergency use of a computed tomographic (CT) protocol comprising unenhanced CT, head and neck CT angiography, and whole-brain CT perfusion. MATERIALS AND METHODS: By using a retrospective patient database from a tertiary care facility and publicly available cost data, the authors derived the potential savings from the use of CT angiography. CT perfusion, or both at hospital arrival by means of a cost model. The cost of the CT angiography-CT perfusion protocol was determined from Medicare reimbursement rates and compared with that of traditional imaging protocols. Cost savings were estimated as a decrease in the length of stay for most stroke patients, whereas the most benign (lacunar) strokes were assumed to be managed in a non-acute setting. Misdiagnosis cost (erroneously not admitting a patient with nonlacunar stroke) was calculated as the cost of a severe complication. Sensitivity testing included varying the percentage of misdiagnosed patients and admitting patients with lacunar stroke. RESULTS: The nationwide net savings that would result from the adoption of the CT angiography-CT perfusion protocol are in the $1.2 billion range (-$154 million to $2.1 billion) when patients with lacunar strokes are treated nonacutely and $1.8 billion when those patients are admitted for acute care. CONCLUSION: The results demonstrate the potential effect of implementing a CT angiography-CT perfusion protocol. In particular, prompt CT angiography-CT perfusion imaging could have an effect on the cost of acute care in the treatment of stroke.