Aortic branch artery pseudoaneurysms accompanying aortic dissection. Part I. Pseudoaneurysm anatomy

PURPOSE: Small areas of blood flow are sometimes seen within an otherwise thrombosed false lumen on computed tomography (CT) scans of intramural hematomas of the aorta. These are blood-filled spaces that, although they have no apparent communication with the true lumen, appear isodense with the aorta on contrast-enhanced CT scans. The purpose of this report is to describe angiographic and autopsy studies that establish the nature of this entity and describe the principal CT features distinguishing it from a penetrating ulcer. MATERIALS AND METHODS: Conventional angiographic and CT aorta findings in two cases with small collections of contrast material within an otherwise thrombosed false lumen of an aortic dissection are discussed. Also examined is another case with pathologic and histologic findings in addition to those of small collections of contrast material within an otherwise thrombosed false lumen of an aortic dissection, which illustrate the pathoanatomy of these lesions. RESULTS: Angiographic and necropsy evidence shows that some of these lesions represent branch artery pseudoaneurysms and, as such, are secondary to an intramural hematoma, not the primary cause of it. CONCLUSIONS: Difficulty in demonstrating communication between these collections of contrast material and the adjacent true lumen of the aorta on helical CT examinations and the characteristic location of these lesions along the nonpleural portion of the aortic circumference distinguish them from penetrating ulcers and should suggest the diagnosis of branch artery pseudoaneurysm. Demonstration of a branch artery originating from the contrast collection confirms the diagnosis. These branch artery pseudoaneurysms should be distinguished from penetrating atherosclerotic ulcers.     

The normal distribution of thoracoabdominal aorta small branch artery ostia

The purpose of this study was to determine the normal distribution of aortic branch artery ostia. CT scans of 100 subjects were retrospectively reviewed. The angular distributions of the aorta with respect to the center of the T3 to L4 vertebral bodies, and of branch artery origins with respect to the center of the aorta were measured. At each vertebral body level the distribution of intercostal/lumbar arteries and other branch arteries were calculated. The proximal descending aorta is posteriorly placed becoming a midline structure, at the thoracolumbar junction, and remains anterior to the vertebral bodies within the abdomen. The intercostal and lumbar artery ostia have a distinct distribution. At each vertebral level from T3 caudally, one intercostal artery originates from the posterior wall of the aorta throughout the thoracic aorta, while the other intercostal artery originates from the medial wall of the descending thoracic aorta high in the chest, posteromedially from the mid-thoracic aorta, and from the posterior wall of the aorta low in the chest. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Lumbar branches originate only from the posterior wall of the abdominal aorta. Aortic branch artery origins arise with a bimodal distribution and have a characteristic location. Mediastinal branches of the thoracic aorta originate from the medial and anterior wall. Knowing the location of aortic branch artery ostia may help distinguish branch artery pseudoaneurysms from penetrating ulcers.     

MR evaluation of chronic aortic dissection

Thirty patients with suspected or known chronic aortic dissection were imaged with magnetic resonance (MR), CT, and angiography. Five of these patients had previously undergone surgical repair of the ascending aorta for a type A dissection. Magnetic resonance demonstrated an intimal flap and a double lumen in 25 cases. In four cases with a thrombosed false lumen, proved angiographically, an intimal flap and double channel were not seen. In two of four aortic dissections with a thrombosed false lumen, CT made the diagnosis by showing displaced intimal calcifications not visualized on MR. In one case the aortic dissection was made on CT and angiography but was not supported by MR which showed an aortic aneurysm, subsequently confirmed at surgery. Magnetic resonance, CT, and aortography differentiated between type A (nine patients) or B (20 patients) dissection in all cases and demonstrated extension into the abdominal aorta. Extension into the iliac arteries was seen on MR in three patients but missed in nine patients. Magnetic resonance differentiated the true and false lumen in all but one case. Thrombosis of the false channel was identified in four cases by a decrease in signal intensity on the second echo image. Cardiac gating and longitudinal contiguous sections seemed to be more suitable for appreciation of the relationships with arch vessels. Transverse contiguous slices allowed determination of the origin of celiac, mesenteric, and renal arteries from either the true or the false lumen. This study confirms that MR is an accurate and noninvasive method for the evaluation and follow-up of chronic aortic dissection, obviating the need for iodinated contrast media.     

多层螺旋CT血管成像在主动脉壁间血肿的临床应用

目的探讨主动脉壁间血肿（IMH）MSCT表现和诊断价值。方法10例经多层螺旋CT诊断及临床证实的IMH,男6例,女4例。使用16层螺旋CT检查,应用多平面重建、最大密度投影和容积成像等后处理方法显示壁间血肿及穿透性溃疡。结果10例IMH中,A型2例,B型8例,其中2例局限于胸主动脉,6例累及胸腹主动脉（止于肾动脉上方2例,髂总动脉分叉上方2例,2例累及双侧髂总动脉）。MSCT表现为主动脉腔内新月形或环形充盈缺损,内壁较光整,钙化内膜片内移及局灶性尖角样穿透溃疡形成,主动脉腔内无明确内膜片显示。结论多层螺旋CT能为主动脉壁间血肿的诊断、鉴别诊断和治疗提供准确的信息。     

Postoperative evaluation of composite aortic grafts: comparison of angiography and CT

Postoperative angiography and computerised tomography were performed in 10 patients 8 to 57 months after surgical repair (nine composite, one distal graft) of aneurysms of the thoracic aorta (six dissecting, four true aneurysms). Angiography and angio-CT showed chronic dissection of the distal aorta in five of six patients with dissecting aneurysms and detected a pseudoaneurysm originating from the distal suture line in another patient. CT may serve as an initial procedure for postoperative examinations after surgery of aortic aneurysms to demonstrate the state of the false lumen and the formation of pseudoaneurysms. The coronary arteries and aortic valve function have to be evaluated by angiography.     

Aortic Branch Artery Pseudoaneurysms Associated with Intramural Hematoma: When and How to Do Endovascular Embolization

Purpose

To describe when and how to perform endovascular embolization of aortic branch artery pseudoaneurysms associated with type A and type B intramural hematoma (IMH) involving the descending thoracic and abdominal aorta (DeBakey I and III) that increased significantly in size during follow-up.

Materials and Methods

Sixty-one patients (39 men; mean ± standard deviation age 66.1 ± 11.2 years) with acute IMH undergoing at least two multidetector computed tomographic examinations during follow-up for 12 months or longer were enrolled. Overall, 48 patients (31 men, age 65.9 ± 11.5) had type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III).

Results

Among the 48 patients, 26 (54 %; 17 men, aged 64.3 ± 11.4 years) had 71 aortic branch artery pseudoaneurysms. Overall, during a mean follow-up of 22.1 ± 9.5 months (range 12–42 months), 31 (44 %) pseudoaneurysms disappeared; 22 (31 %) decreased in size; two (3 %) remained stable; and 16 (22 %) increased in size. Among the 16 pseudoaneurysms with increasing size, five of these (three intercostal arteries, one combined intercostobronchial/intercostal arteries, one renal artery), present in five symptomatic patients, had a significant increase in size (thickness >10 mm; width and length >20 mm). These five patients underwent endovascular embolization with coils and/or Amplatzer Vascular Plug. In all patients, complete thrombosis and exclusion of aortic pseudoaneurysm and relief of back pain were achieved.

Conclusion

Aortic branch artery pseudoaneurysms associated with type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III) may be considered relatively benign lesions. However, a small number may grow in size or extend longitudinally with clinical symptoms during follow-up, and in these cases, endovascular embolization can be an effective and safe procedure.     

Magnetic resonance imaging of aortic aneurysm

Magnetic resonance (MR) imaging in 16 patients with aortic aneurysm used a field of 5,000 Gauss and spin echo multisection imaging with two echos. Results were compared retrospectively with those of echotomography, computed tomography and angiography. Surgical exploration allowed correlation with histopathology in 13 patients. The external diameter of aneurysm and of its residual lumen and length of aneurysm were in each case evaluated precisely by MR. In patients with abdominal aneurysm, MR images identified the limits of the aneurysm in relation to renal and iliac arteries. In aneurysms of thoracic aorta, synchronization of signal with an ECG and longitudinal imaging provided data on relations of aneurysm with supraaortic trunks. In 2 patients with extensive, partially thrombosed thoracic and abdominal aorta aneurysm, MR imaging could not eliminate a diagnosis of aortic dissection with thrombosed false lumen. Finally, aortic wall calcifications were never apparent on MR images.     

旋转肾动脉DSA的临床应用

目的　探讨旋转肾动脉DSA临床应用的可行性。方法　回顾性分析 48例肾肿瘤患者腹主动脉DSA检查中肾动脉的解剖情况。测量 5 0例腹部CT增强扫描肾动脉开口的位置、方向。观察 16例旋转肾动脉DSA的效果。结果　 48例常规腹主动脉DSA中 ,右肾动脉开口、主干及分支显示不清分别为 12例、5例及 10例。左肾动脉开口、主干及分支显示不清分别为 8例、4例及 6例。 5 0例腹部CT增强扫描显示 :右肾动脉开口位于腹主动脉侧壁、侧前壁以及侧后壁分别为 4例、2 4例及 3例。左肾动脉开口位于腹主动脉侧壁、侧前壁以及侧后壁分别为 13例、2例及 13例。两肾动脉开口位于腹主动脉同一水平面 11例。 16例旋转肾动脉DSA中 ,两侧肾动脉旋转 6例 ,单侧肾动脉旋转 10例。肾动脉开口狭窄 3例 ,主干狭窄 2例 ,肾肿瘤供血动脉 7例 ,排除肾动脉狭窄 4例。结论　旋转肾动脉DSA有助于详细显示肾动脉的解剖细节。     

CT diagnosis of acute aortic dissection; clinical importance of acute aortic dissection with non-opacified false lumen

Sixteen (47.5%) of 35 patients with acute aortic dissection showed a non-opacified crescent in the aorta on an initial contrast CT. Seven of these 16 patients underwent cineangiography soon after the initial CT, and in all 7 patients, neither an intimal tear nor an intimal flap was obtained. All but one of above 16 patients were followed by CT. Mean duration of follow-up was 9.6 months. In 10 of 15 patients with non-opacified false lumen, the false lumen remained non-opacified until the last examination. Moreover, in 6 of these 10 patients, the false lumen shrunk, and in the other 3, it disappeared completely on follow-up CT. On the other hand, in remaining 5 of these 15 patients who were initially diagnosed to have non-opacified false lumen, the false lumen became opacified and enlarged in size on follow-up CT performed in the first 14 weeks. Moreover, in 4 of these 5 patients, the false lumen became opacified in the only first 6 weeks. No matter how intensive care should be paid at least for the first 6 weeks, it seems that patients with aortic dissection which have non-opacified false lumen had good prognosis in comparison to patients with ordinary aortic dissections which have opacified false lumen. We believe aortic dissection with non-opacified false lumen may consist of two type of aortic dissection, one has no intimal tear, the other has some intimal tears and a thrombosed false lumen. In conclusion, CT is the most useful modality in diagnosing acute aortic dissection. The reasons are the incidence of acute aortic dissection with non-opacified false lumen was high, patients with non-opacified false lumen had good prognosis, and it was difficult to diagnose aortic dissection with non-opacified false lumen by conventional cineangiography and/or DSA.     

MDCT findings of aortic branch artery pseudoaneurysms associated with type B intramural haematoma

Purpose

The purpose of this study was to evaluate prevalence, morphological characteristics and evolution of aortic branch artery pseudoaneurysms associated with type B aortic intramural haematoma (IMH) using multidetector computed tomography (MDCT).

Materials and methods

We enrolled 14 patients (nine men; mean age 64.6±9.6; range 42?C75 years) with a diagnosis in the acute phase of type B IMH without evidence of intimal tear. All patients underwent clinical and MDCT follow-up.

Results

Twenty-two pseudoaneurysms in six patients (6/14, 43%) were observed at MDCT. In the majority of patients (5/6, 83%) the pseudoaneurysms were multiple and involved the branches of the descending thoracic aorta (14/22, 64%), mainly the intercostal arteries (11/22, 50%). At a mean follow-up of 10.6±8.7 months, 21 pseudoaneurysms showed resolution, reduction or dimensional stability (95%), whereas only one increased in size (5%).

Conclusions

Aortic branch artery pseudoaneurysms associated with IMH may be considered a benign disease, as the majority of cases resolved or did not change in size, with haematoma resorption. However, because a dynamic change in pseudoaneurysms in the acute and subacute phases was frequently observed, close clinical and imaging follow-up is mandatory.     

Multidetector CT angiography using a dual-head power injector and bolus tracking for the diagnosis of aortic aneurysms at reduced contrast material dosage

RATIONALE AND OBJECTIVES: To establish the utility of multidetector computed tomography (CT) angiography using dual-head power injector in the diagnosis of aortic diseases. METHODS: In a prospective study, 151 patients with aortic diseases were examined by four-detector CT. Scanning was performed using bolus tracking technique. In all patients nonionic contrast was injected at the rate of 1.5 mL/sec. One hundred one patients were examined with dual-head power injector using 0.6 mL/kg contrast flushed by 30 mL of saline solution (group D). Fifty patients were examined with single-head power injector using 1.0 mL/kg contrast only (group S). We evaluated CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and bilateral common femoral arteries. RESULTS: There were no statistically significant difference of CT values at descending aorta, upper abdominal aorta, abdominal aortic bifurcation, and right common femoral artery. At left common femoral artery, CT values in group D were higher than those in group S with statistically difference (P < .05). In group D, about 40% dose reduction was achieved without reducing image qualities. CONCLUSION: Multidetector CT angiography using dual-head power injector was valuable for the contrast dose reduction of aortic diseases.     

外伤性主动脉夹层的CT诊断(附2例报告)

目的：探讨外伤性主动脉夹层的早期CT表现。方法：回顾性分析在我院漏诊及确诊的外伤性主动脉夹层的CT表现。2例中1例行3次CT平扫,1例行CT平扫和增强扫描。结果：2例均为DeBakeyIU型主动脉夹层,1例3次CT平扫示降主动脉管腔进行性增宽,伴双侧胸腔积液;此例因漏诊,患者于2周后死亡。另1例CT平扫示降主动脉增粗,CT增强扫描明确诊断,主要表现为降主动脉扩张,可见真腔、假腔及内膜线;此例患者行支架植入术后,患者预后良好。结论：对于胸部外伤患者,CT平扫时应注意观察主动脉的直径,如果降主动脉增粗、尤其是进行性增粗时,应考虑主动脉夹层的可能。     

64层螺旋CT对主动脉夹层的应用价值

目的:探讨64层螺旋CT诊断主动脉夹层的临床价值。方法:39例拟诊为主动脉病变的患者作为本组研究对象,对所有患者行CT平扫及增强扫描。CT平扫图像上观察内膜钙化的移位、主动脉直径扩大、心包和/或纵隔积血、胸腔积液/血。并对A型和B型主动脉夹层的平扫征象进行统计学比较。CT增强图像上观察低密度的内膜瓣、破口(入口和再入口)、真假腔及主要动脉分支受累情况。结果:21例主动脉夹层中,CT平扫观察到钙化的内膜瓣移位9例(42.9%),主动脉直径增宽8例(38.1%),心包和/或纵隔积血8例(38.1%),胸腔积液/血5例(19.0%)。CT增强扫描对主动脉夹层内膜瓣的显示率达100%(21/21),对真、假腔的显示率为100%(21/21),对破口的显示率为85.7%(18/21)。8例(38.1%)弓上血管受累,5例(19.0%)内脏血管受累。结论:64层螺旋CT对主动脉夹层有较高的诊断价值,能较好的显示夹层的真假腔、内膜瓣及破口,并且可以显示主要动脉受累情况,为外科的手术治疗提供重要信息。     

Separate origins of the left internal and external carotid arteries from the aorta in a patient with intracerebral hemorrhage

Agenesis of the left common carotid artery with separate origins of the left internal and external carotid arteries from the aorta is an extremely rare anomaly. This anomaly is typically asymptomatic unless associated with other conditions. We report a case of separate origins of the left internal and external carotid arteries from the aorta in a patient with intracerebral hemorrhage. A 42-year-old man was transferred to our hospital by ambulance because of left hemiparesis. Computed tomography scan revealed right putaminal hemorrhage. Computed tomography angiography and digital subtraction angiography demonstrated independent origins of the left internal carotid artery and external carotid artery from the aortic arch. Right internal carotid angiography revealed blood supply to the left anterior cerebral artery and middle cerebral artery via the anterior communicating artery. The separate origins of the left internal and external carotid arteries from the aorta may cause hemodynamic stress to the contralateral side, leading to right intracerebral hemorrhage.     

多层螺旋CT对主动脉夹层动脉瘤的诊断价值

目的探讨多层螺旋CT对主动脉动脉瘤的诊断价值。方法对25例主动脉瘤患者于临床症状出现后进行多层螺旋CT平扫加增强扫描并利用原始数据在AW4．3工作站进行MPR及VR后处理。结果横轴位图像上可观察到真假腔形态、大小、剥脱的内膜片、破口位置及内膜和主动脉壁钙化,MPR重建图像能观察主动脉弓受累情况,确定内膜剥离范围,显示内膜与各分支血管之间的关系,按DeBakey分型,本组患者表现为Ⅰ型4例,Ⅱ型2例,Ⅲ型19例。结论多层螺旋CT能直观、立体显示真、假腔的形态、大小,破口位置及其与大分支血管的关系,因而它应是诊断夹层动脉瘤的首选检查方法。     

Hepatoma feeding arteriogram created by CT during aortography using IVR 64-multidetector-row CT for catheterization in transcatheter arterial chemoembolization for hepatocellular carcinoma

CT during aortography (CTAo) using IVR 64-multidetector-row CT (IVR-64MDCT) enables the rapid and simultaneous depiction of both the hepatic and extrahepatic feeding arteries in hepatocellular carcinoma (HCC), and can be achieved using a reasonable volume of contrast medium. The scan time is approximately 6 s from the diaphragm to the kidney using CTAo with 64MDCT with a slice thickness and slice interval of 0.5 mm. The hepatoma feeding arteriogram appears in the angiographic monitor after CTAo, and can then be used to guide catheterization. We introduce the process for creating a hepatoma feeding arteriogram, synthesized from the following three volume-rendered images: background bone, aorta to hepatic-branch artery, and hepatoma to feeding artery. Uniquely, the hepatoma feeding arteriogram enables investigation of the feeding artery from the tumor side, rather than from the aorta side, and appears superior to selective arteriography in terms of detecting small HCC and its accompanying fine feeding arteries. Identification of these arteries by CT angiography with intravenous contrast medium injection is difficult because of the similarity in CT values between the feeding artery and the surrounding liver, thereby preventing the creation of a hepatoma feeding arteriogram. CTAo accelerates the process of deciding upon the catheter treatment strategy, shifting the decision to the point at which the feeding artery is investigated, because the hepatoma feeding arteriogram enables instant identification of the feeding artery and its connection to the hepatic branch artery. CTAo with IVR-64MDCT can potentially contribute to remarkable advances in IVR, especially transcatheter arterial chemoembolization for HCC.     

Analysis of intimal extent and predictors of renal atrophy in patients with aortic dissection

Background The intimal flap of aortic dissection may extend to the abdominal branches and probably lead to malperfusion syndrome. Renal malperfusion and renal atrophy are significantly related to patient outcomes. Purpose To study the extent of the intimal flap and predisposing factors for renal atrophy in patients with aortic dissection. Material and Methods From January 2001 to June 2008, 176 (137 men, aged 21-86 years, mean 51.9 years) of 225 subjects with aortic dissection and computed tomography (CT) met the inclusion criteria for this study. Of these 176 patients, 35 (19.9%) developed unilateral renal atrophy. A review of the CT was conducted to classify aortic branch vessel perfusion into three types: type 1, in which the branch vessels are perfused exclusively from the true lumen; type 2, in which the branches are perfused from both the true and false lumens; and type 3, in which the branches are perfused exclusively from the false lumen. Variables including age, gender, type of aortic dissection, type of perfusion of the abdominal branches, and the presence of thrombi in the false lumen were analyzed to determine whether these factors were related to the left or right side and global or focal renal atrophy. Results Of 880 abdominal branches in 176 patients, 622 (70.7%) were classed as perfusion type 1, 50 (5.7%) as type 2, and 208 (23.6%) as type 3. Type 3 perfusion was most commonly observed in the left renal artery, at a frequency of 31.7% (66/208). Partial thrombosis in the false lumen above the level of the renal arteries was seen in 68.8% of patients; such thrombi and type 3 perfusion of the renal artery were significantly related to renal atrophy. The laterality (left or right) and extent (global or focal) of renal atrophy were not related to age, gender, type of aortic dissection, or perfusion type. Conclusion Type 3 perfusion is most frequent in the left renal artery, and such perfusion and partial thrombi in the false lumen above the renal arteries are significantly related to the development of renal atrophy.     

Differentiation between dissection and a true aneurysm of the descending thoracic aorta using magnetic resonance tomography

The case reviewed here demonstrates that magnetic resonance imaging in contrast to CT and i.v. DSA can differentiate between aortic dissection with partially thrombosed false lumen and a true aneurysm using the spin-echo and the gradient-echo technique. The gradient-echo technique was able to depict the moving intimal flap as well as the higher blood flow velocity in the true lumen.     

Cervical vertebral artery variations: an anatomic study

In this article, we present 5 cases of uncommon anomalous vertebral arteries and discuss the possible embryologic etiologies. These cases include a left vertebral artery as the 2nd branch off the left subclavian, a left vertebral artery with 2 origins, a right vertebral artery arising as the last branch off the aorta, a right vertebral artery arising as the 2nd branch off the right subclavian artery, and right vertebral artery with proximal duplication as the 2nd branch off the right subclavian artery.     

Femoral artery pseudoaneurysms: value of color Doppler sonography in predicting which ones will thrombose without treatment.

OBJECTIVE. The purpose of this study was to evaluate the Doppler imaging characteristics of femoral artery pseudoaneurysms occurring after cardiac catheterization to determine if color Doppler sonography can be used to predict which pseudoaneurysms would ultimately thrombose spontaneously. MATERIALS AND METHODS. Over a 30-month-period, 24 pseudoaneurysms were studied with serial color Doppler sonography. The color flow, B-mode, and Doppler spectral images and clinical records of patients whose pseudoaneurysms demonstrated spontaneous thrombosis were compared with those of patients who required surgical repair of the pseudoaneurysm. RESULTS. We found no statistically significant differences between the patients whose pseudoaneurysms demonstrated spontaneous thrombosis and those treated surgically in regard to clinical parameters or the volume of the pseudoaneurysm, percentage of flow within the pseudoaneurysm, ratio of forward to reversed flow velocity in the pseudoaneurysm neck, duration of diastolic flow in the pseudoaneurysm neck, or length of pseudoaneurysm neck. However, on color Doppler images, the volume of flow in the lumens of pseudoaneurysms that thrombosed spontaneously (1.8 +/- 3.3 ml) was significantly smaller than the volume of flow in the lumens of those treated surgically (4.4 +/- 3.2, ml, p = .02). CONCLUSION. We conclude that pseudoaneurysms with small volumes of flow in the lumen are more likely to thrombose than are those with large volumes of flow in the lumen. However, color Doppler sonographic characteristics cannot be used to predict subsequent thrombosis.