Imaging of vascular inflammation with ultrasound

Clinical History

30-year-old woman with type I diabetes presented with high erythrocyte sedimentation rate (ESR) during pregnancy. No pathological correlation was revealed. Two months after the delivery of her baby the patient developed carotidynia over right neck and tinnitus. Malaise and night sweats were also reported. ESR levels were persistently high.

Imaging Findings

Carotid duplex ultrasound demonstrated homogeneous circumferential smooth thickening of the wall of the right common and the external carotid artery (Fig. 1, 2). MRA of the thoracic and abdominal aorta did not delineate other vascular lesions. An ultrasound examination of the abdomen showed multiple hypoechoic round lesions in the spleen with normal splenic size (Fig. 3). FDG-PET/CT revealed increased FDG uptake (SUVmax 5.3) that suggested lymphomatous involvement of the spleen. There was also increased uptake of FDG in the right side of the neck. The patient received chemotherapeutic agents and corticosteroids. ESR levels decreased but did not reach normal values (58 mm/hr). Two years after, in an ultrasound examination the patient showed extension of the pathological tissue to the innominate artery and similar pathological tissue around the wall of the left common carotid artery. Hypoechoic lesions of the spleen appeared less in number and more subtle to discern with ultrasound.

Discussion

Takayasu arteritis (TA) is an idiopathic medium and large vessel obliterative vasculitis that typically affects the aorta and its primary branches [1]. TA is reported in young individuals, mainly women of childbearing age [1]. Histologically, inflammatory cells such as mononuclear leukocytes and giant cells sum up in the adventitia and progressively extend to the intima [2]. In the early stages there is a perivascular cuffing of the vasa vasorum that is followed by fibrosis and calcification leading to segmental stenosis and occlusion [2]. Dilatation and aneurysm formation may be either primary or secondary arterial wall changes in TA [3]. A biopsy may not be practical if only the carotid arteries are involved. Angiography is particularly useful for the detection of the affected vessels [1]. A magnetic resonance study may be sufficient to delineate vascular lesions without proceeding to invasive angiographic methods [4]. Asymmetrical vascular bruits in large vessels, especially in young patients, necessitate ultrasound screening. Activity of the disease is evaluated by clinical findings such as extremity or visceral ischaemia, malaise, myalgias, arthralgias, night sweats and fever [5]. Yet the disease may have a quiescent clinical course and 50% of the patients may have normal ESR values [3]. In this setting, the activity of the disease may be documented by sequential angiographic studies that demonstrate new vascular abnormalities.
TA is thought to be secondary to an autoimmune process. Paraneoplastic TA should be considered on the basis of a suspicious clinical history or laboratory findings, or in patients who fail to respond to aggressive immunosuppressive therapy.
B-mode ultrasound shows the presence of smooth, concentric mildly echogenic wall thickening. The ultrasound findings, especially at the level of the carotid arteries are highly specific for TA and are characterised as macaroni sign [5].
Duplex ultrasound reveals increased levels of systolic and diastolic velocities that suggest stenotic changes. The presence of wall thickening that is not accompanied with increase in the velocity may be related to non-stenotic changes that may entail a more recent disease course [1].
To estimate the activity of the disease a contrast ultrasound examination or angiographic methods with contrast agents may help to identify contrast enhancement that is reported to correlate with ESR and CRP levels [6]. In the early phase of the disease, the enhancement may involve only the adventia while the media-intima may appear hypodense creating a double layer appearance of the arterial wall [5].

Differential Diagnosis List

Final Diagnosis

Takayasu arteritis

URL:	https://eurorad.org/case/14883
DOI:	10.1594/EURORAD/CASE.14883
ISSN:	1563-4086