Role of multi-parametric ultrasound in transient perivascular inflammation of the carotid artery syndrome

Abstract

Introduction: The term "carotidynia" has been used to describe a symptom or a nosologic entity characterized by pain in the lateral neck region and over the carotid bifurcation. Recent advances in diagnostic imaging and the introduction of diagnostic criteria have led to the adoption of term "Transient perivascular inflammation of the carotid artery" (TIPIC) syndrome.

Method: A retrospective analysis of the Radiology Department's database was performed to identify cases with the diagnosis of TIPIC syndrome. The purpose was to identify ultrasound images including B-mode technique, colour, power Doppler technique and contrast-enhanced ultrasound (CEUS).

Findings: In total, five patients with the diagnosis of TIPIC syndrome are presented in this review. TIPIC syndrome is a clinic-radiologic entity characterized by pain over the carotid area, a symptom referring to a wide differential diagnosis where imaging plays a crucial role for proper diagnosis and treatment. Characteristic imaging findings on conventional ultrasound and CEUS are presented in this review.

Discussion: TIPIC syndrome can be investigated with virtually any imaging modality. Ultrasound typically reveals perivascular infiltration and a hypoechoic intimal plaque, while no significant luminal narrowing is appreciated. Computed tomography angiography and magnetic resonance angiography also demonstrate these vascular wall changes primarily affecting the distal common carotid artery, the carotid bulb and possibly the internal carotid artery proximal part. Contrast enhancement is a very characteristic and constant finding of TIPIC lesions, suggestive of the inflammatory nature of the disease and can be appreciated on computed tomography angiography and magnetic resonance angiography. CEUS has been recently used and successfully observed contrast enhancement of the lesions, similar to computed tomography angiography and magnetic resonance angiography.

Conclusion: Ultrasound remains the first-line modality for the evaluation of TIPIC syndrome, capable of providing all the information needed, especially if supplemented with the administration of microbubbles so that the enhancement of lesions can be evaluated.

Keywords: Carotid; contrast-enhanced ultrasound; transient perivascular inflammation of the carotid artery syndrome; ultrasound.

Figure 1.

A 52-year-old male patient presenting with pain over the carotid area and diagnosed with TIPIC syndrome. Axial B-mode image (a) showing perivascular infiltration in the form of hypoechoic mural thickening eccentrically affecting the external carotid artery (arrowhead). Axial (b) and longitudinal (c) power Doppler images showing only mild luminal narrowing. Longitudinal CEUS image after the administration of microbubbles (d) and a few seconds later (e) showing the presence of microbubbles within the hypoechoic lesions. Temporal maximum intensity projection CEUS image (f) showing the enhancement of lesions. CEUS also provides the possibility to quantify lesion enhancement (g) using time-intensity curves. Note that the lesion (green curve) enhances equally to the lumen (yellow curve) and a few seconds later than the latter. Axial (h) and sagittal (i) CTA images showing the eccentric mural thickening affecting the left proximal external carotid artery. Note the presence of mural thickening affecting the media and adventitia, adjacent fat stranding and the soft-tissue intimal component of the lesion causing mild luminal stenosis. Intense enhancement was demonstrated after the administration of contrast medium as it is demonstrated in the comparative image prior and after to the administration of contrast medium (j).

Figure 2.

A 40-year old male patient presented with recurrent short episodes of pain during the last weeks located at the region of the right carotid bifurcation. The pain increased by turning the head to the left side and occasionally the pain irradiated to the ipsilateral ear. It vanished within few days to a course of non-steroidal anti-inflammatory drug (ibuprofen). The patient was a cigarette smoker, but no other cardiovascular risk factors were known. He did not remember any previous trauma of the neck. Based on the clinical presentation and the results on standard and CEUS imaging, the diagnosis of TIPIC syndrome was made. B-mode US imaging using a 3–9 MHz linear probe revealed a perivascular hypoechogenic thickening at the origin of the right external carotid artery with outward extension of the vessel (a) but no relevant stenosis of the carotid artery on colour-Doppler US (b). The mass had an onionskin like appearance. After a bolus injection of 2.5 ml SonoVue™, the lesion in the longitudinal (c) and transversal view (d) revealed microbubbles within perivascular lesion on CEUS suggesting a vascularized and non-specific inflammatory process.

Figure 3.

A 68-year-old female subject with arterial hypertension and smoking history. She had pain at the left carotid bifurcation without trauma and no neurological symptoms. The pain decreased after treatment with a non-steroidal anti-inflammatory drug (ibuprofen). B-mode US imaging using a 5–12 MHz linear probe a perivascular hypoechogenic thickening with a onionskin like appearance at the origin of the left carotid artery in the longitudinal view (a) and in the cross-section view (b) with outward extension of the vessel and subjacent a hyperechoic, calcified luminal plaque but no relevant stenosis of the carotid artery. After 10 days, the patient was spontaneously asymptomatic. B-mode US imaging revealed a complete disappearance of the previously documented perivascular thickening at the origin of the left carotid artery. In the longitudinal (c) and cross-section view (d), only the calcified non-stenotic carotid plaque was left. Based on the clinical presentation, the course with spontaneous clear resolution of the symptoms and morphological alteration on standard US imaging the diagnosis of TIPIC syndrome in the region of an arteriosclerotic carotid plaque was made.