Multi-modal imaging for the diagnosis of spontaneous visceral artery dissection: A case report

Abstract

BACKGROUND

Spontaneous visceral artery dissection (SVAD) is a rare condition that affects the visceral arteries, such as the celiac, superior mesenteric, and inferior mesenteric arteries, without involving the aorta. Organ ischemia or hemorrhage from vessel rupture can occur in SVAD; therefore, prompt detection and management is essential. Contrast-enhanced computed tomography (CECT) has been used to diagnose most of the previous cases, but few studies have explored the potential of contrast-enhanced ultrasound (CEUS) for early detection of this disease.

CASE SUMMARY

A 53-year-old male presented with complaints of poor appetite and abnormal liver function for the past 6 months. He had previously undergone transabdominal splenectomy, esophagogastric devascularization, and cholecystectomy for gallstones and severe portal hypertension. Liver ultrasound was performed in our department to assess liver status. An abnormal hepatic artery spectrum was observed, and dissection involving both the celiac artery and the common hepatic artery was observed. A CEUS was then performed and clearly showed the entry site of the intimal tear and the false lumen, and dissection was subsequently confirmed by CECT. The patient was asymptomatic; therefore, treatment to control the blood pressure was provided, and follow-up was recommended. After 6 months of follow-up, the celiac artery was found to be dilated with an adherent thrombus visible in the wall, and the common hepatic artery was occluded with the presence of collateralization. Despite these findings, no significant changes in liver function were observed.

CONCLUSION

Multi-modal imaging is effective in diagnosing SVAD, and conservative treatment is a choice for asymptomatic patients.

Key Words: Spontaneous visceral artery dissection; Celiac artery dissection; Contrast-enhanced computed tomography; Contrast-enhanced ultrasound; Case report

Core Tip: Spontaneous visceral artery dissection (SVAD) is a rare condition. Imaging examinations play an important role in the diagnosis of SVAD. Contrast-enhanced computed tomography has been used to diagnose most of the previous cases, but few studies have explored the potential of contrast-enhanced ultrasound (CEUS) for early detection of this disease. In our case, CEUS was used for early detection of the dissection, which was confirmed using other imaging modalities, and the condition was successfully managed with conservative therapy. This case demonstrates the diagnostic value of multi-modal imaging for this uncommon disease.

INTRODUCTION

Artery dissection is a life-threatening condition that occurs when a tear or rupture in the arterial lining allows blood to enter the arterial wall, separating its layers, and disrupting blood flow. Aortic dissection is a severe and fatal vascular disease with an annual incidence of 3.5-6/100000 per year[1]. Spontaneous visceral artery dissection (SVAD), which occurs without accompanying aortic dissection, is a rare condition. According to a recent systematic review, the main risk factors for SVAD are middle-aged male, hypertension or dyslipidemia, and smoking[2]. Additionally, SVAD may be caused by compression of the median arcuate ligament or a history of abdominal surgery[3,4]. Treatment for SVAD varies depending on the patient’s condition. Asymptomatic patients usually receive conservative treatment, whereas patients with persistent abdominal pain, ruptured aneurysm, or organ ischemia need urgent intervention, such as endovascular treatment[5].

Most of the previous cases have been diagnosed by contrast-enhanced computed tomography (CECT)[2,6], but the potential of contrast-enhanced ultrasound (CEUS) for early detection of this disease remains underexplored. We used CEUS to identify a case of artery dissection involving the celiac and common hepatic arteries at an early stage.

CASE PRESENTATION

Chief complaints

A 53-year-old male was admitted to our hospital with complaints of poor appetite and abnormal liver function during the previous 6 months.

History of present illness

Blood tests at the local hospital showed abnormalities in liver and renal functions, and ultrasound showed a hypoechoic nodule in the liver. The patient was transferred to our hospital for further diagnosis and treatment.

History of past illness

The patient had a history of viral hepatitis B for more than 20 years and had undergone transabdominal splenectomy, esophagogastric devascularization, and cholecystectomy 4 years earlier at our hospital for gallstones and severe portal hypertension. The patient had no history of hypertension, diabetes mellitus, or other abdominal surgery.

Personal and family history

There was no other personal or family history of acute or chronic disease.

Physical examination

The patient showed no jaundice on visual examination and no tenderness, rebound tenderness, or muscle tension on abdominal palpation.

Laboratory examinations

Liver function tests were performed at baseline, 3 months, and 6 months. Alanine aminotransferase was 45, 46, and 34 IU/L, respectively (reference range, < 50 IU/L). Aspartate aminotransferase was 38, 35, and 36 IU/L, respectively (reference range, < 40 IU/L). Total bilirubin was 31.9, 32.7, and 34.4 µmol/L, respectively (reference range, 5 µmol/L to 28 µmol/L).

Imaging examinations

Color Doppler imaging showed that the flow of blood in the common hepatic artery was slowed, and the resistance index was reduced. Additionally, right hepatic artery blood flow accelerating time was significantly prolonged, and blood flow was slowed (Figure 1A and B). A dissection of the celiac artery was detected, with two opposite flow signals in the lumen (Figure 1C and D). In the CEUS imaging, the contrast agent extravasated the vessel wall, and the common hepatic artery was narrowed (Figure 1E and F). The CECT images revealed a linear low-density area in the celiac artery wall, heterogeneous thickening of the celiac artery, and thinning of the common hepatic artery, with low-density material attached to their walls (Figure 2A and B); at 3 months of follow-up, the low-density material increased, and the common hepatic artery was narrowed (Figure 2C and D); at 6 months of follow-up, the celiac artery wall had more low-density material, and the common hepatic artery was occluded with evidence of collateralization (Figure 2E and F).

Figure 1 Ultrasound images of the patient. A and B: Hepatic artery and right hepatic artery flow spectrum; C: Rupture of the vessel wall (orange arrow); D: Color Doppler flow imaging of the celiac artery; E and F: Contrast-enhanced ultrasound imaging shows contrast agent extravasation outside the vessel wall and narrowing of the common hepatic artery (orange arrow).

Figure 2 Contrast-enhanced computed tomography images of the patient. A and B: Artery dissection is shown in the first computed tomography examination (orange arrow); C and D: Narrowing of the common hepatic artery at the 3-month follow-up (orange arrow); E and F: Occlusion of the common hepatic artery with collateralization at the 6-month follow-up (orange arrow).

FINAL DIAGNOSIS

Based on the analysis of multiple imaging information, the patient was finally diagnosed with SVAD.

TREATMENT

The patient chose conservative treatment rather than surgical intervention. During follow-up, the patient was treated with a daily oral dose of 0.5 mg entecavir, 12.5 mg carvedilol, and 5 mg amlodipine besylate.

OUTCOME AND FOLLOW-UP

During the follow-up period of 6 months, the patient did not experience any symptoms (e.g., abdominal pain), and the liver function tests did not show any significant abnormal changes.

DISCUSSION

The three main branches of the visceral arteries are the celiac, superior mesenteric, and inferior mesenteric arteries. An SVAD is a condition in which these arteries experience a tear or rupture in their lining without affecting the aorta. Superior mesenteric artery dissection is the most prevalent among the SVADs, followed by celiac artery dissection (CAD)[6]. CAD may propagate along the vessel wall and compromise its branches, such as the splenic and common hepatic arteries. With advancement and wider use of diagnostic imaging modalities in clinical settings, the detection rate of SVAD is increasing[7], but spontaneous celiac artery and common hepatic artery dissections are still extremely rare. When it occurs, SVAD requires prompt diagnosis and treatment, otherwise organ ischemia or vascular rupture causing massive bleeding may occur.

According to a recent systematic review, approximately 60% of patients with CAD exhibited nonspecific clinical symptoms, such as abdominal pain, malaise, and vomiting[2]. However, SVAD is a potential diagnosis of an acute abdomen that warrants clinical concern among patients who present with persistent abdominal pain[8]. The etiology of CAD is obscure. A systematic review revealed that hypertension, smoking, and hyperlipidemia were the top three risk factors for this patient group[2]. Furthermore, one possible cause is the compression of the median arcuate ligament, which exerts constant friction or stress on the celiac artery from the diaphragm during respiration[3]. Additionally, it was implicated that surgical manipulation may be a risk factor for celiac or hepatic artery dissection[4,9]. Our patient had a long history of alcohol consumption and smoking without confirmed hypertension. He had also undergone transabdominal splenectomy, esophagogastric devascularization and cholecystectomy 4 years earlier. He reported no other history of abdominal surgery. We hypothesize that the past trauma from abdominal surgery and the hemodynamic changes might have triggered the dissection of the celiac and common hepatic arteries.

Imaging plays a crucial role in the diagnosis of CAD, which has increased in prevalence with the advancement of imaging modalities[7]. The preferred diagnostic method for CAD is CECT/Computed tomography angiography, while magnetic resonance angiography and ultrasound are also viable options. Digital subtraction angiography is the gold standard for diagnosis; however, it is invasive. Previous studies have shown that most patients were diagnosed by CECT of the abdomen[2,6]. However, in our case, the patient had an ultrasound of the liver, and the physician observed abnormalities in the spectrum of the hepatic artery. He then traced the examination backward along the arterial course and finally located the artery dissection in the common hepatic artery and the celiac trunk. A CEUS was then performed on the patient. By dynamically observing the distribution of microbubbles in the celiac and common hepatic arteries, the site of the peritoneal rupture in the celiac artery was clearly identified, as well as the blood flow in the true and false lumens. In contrast to the static images of computed tomography, ultrasound imaging not only has the advantage of dynamically observing vessel movement, but has several other advantages. Color Doppler ultrasound can measure the velocity of blood flow at the most significant point of luminal narrowing, thereby indirectly determining the presence of organ ischemia. By observing the distribution of microbubbles, the location of the intimal tear can be visualized, and blood flow and thrombosis in the false lumen can be assessed. When blood flow was slow and could not be visualized on Color Doppler ultrasound, blood flow could be determined by observing the flow or absence of microbubbles, suggesting that CEUS was more sensitive in determining blood flow in the pseudo cavity. Therefore, it was suggested that CEUS be used as an imaging modality for long-term follow-up of patients with CAD[10].

The rates of conservative and surgical treatments for CAD vary widely, largely because of its unpredictable natural course[11]. For asymptomatic patients, doctors mostly recommend conservative treatment or regular follow-up. Conservative treatment consists mainly of antihypertensive, anticoagulant, and/or antiplatelet therapy[7]. Anticoagulation or antiplatelet therapy can help prevent thrombosis and maintain organ perfusion; however, the criteria for use of these agents are unclear. CAD can lead to thrombus formation at the entry site or in the false lumen, which can cause stenosis of the true lumen and obstruct blood flow, resulting in organ ischemia[12]. In our case, even though the hepatic artery was occluded, we did not provide surgical treatment because the liver is an organ with a dual blood supply. The CECT suggested that collateral circulation had formed around the occluded artery, and laboratory tests suggested that the patient did not have significant liver function abnormalities. A significant change in liver function would have been an indication that the CAD may have involved the hepatic artery, resulting in inadequate blood supply to the liver, which did not occur in our case. An additional concern was the possibility of splenic infarction if inhomogeneous splenic perfusion was observed[13], which also was not an issue in our case. Endovascular treatment such as stenting is recommended if symptoms persist, dissection progresses, or the aneurysm continues to enlarge, and surgery is the last option if complications are severe or endovascular treatment fails[14-16].

CONCLUSION

SVAD is a rare condition that requires prompt diagnosis and treatment to prevent organ ischemia or vascular rupture that results in massive bleeding. We identified this case early via CEUS, confirmed the diagnosis with other imaging modalities, and successfully managed it with conservative therapy. This case demonstrated the diagnostic value of multi-modal imaging for this uncommon disease. Conservative treatment is a reasonable choice for asymptomatic patients.