2015 HSC Section 1 Book of Articles

A. Tekes et al. / Clinical Radiology 69 (2014) 443 e 457

subtraction angiography, or magnetic resonance imaging (MRI), and MR angiography/venography (MRA/MRV). US is often used as the fi rst line of imaging, given the lack of ionizing radiation, no need for sedation/general anaes- thesia, and bed-side imaging capabilities. Structural im- aging data can be combined with fl ow dynamics of the VA, which is valuable in the classi fi cation of the lesion. However, operator dependence and small fi eld of view are limiting factors in diagnosis and follow-up. MRI is the reference standard in most cases given the high soft- tissue resolution, different sequences, and fat suppres- sion capabilities enabling clear differentiation/demarca- tion of the VA from surrounding soft tissues, along with dynamic contrast-enhanced (DCE) imaging information. DCE-MRA provides high temporal resolution and pro- duces imaging of the lesion in the arterial, capillary, venous, and delayed venous phases 4,5 in the order of seconds. 6 Rapid DCE-MRA data acquisition is based on a combination of parallel imaging and k-space under- sampling. 7 View-sharing and keyhole techniques are used by fully sampling the central k-space during each acqui- sition, although only a small fraction of the k-space pe- riphery is acquired at the same time. A full k-space periphery is generated for each image by adding infor- mation from previous and subsequent acquisitions to obtain a sharp, high-resolution image with good image contrast. The high-resolution components encoded in the k-space periphery are relatively stable over time, whereas the low-frequency k-space centre carries the signi fi cant contrast changes during bolus passage. The full anatomical extent of the anomaly can be evalu- ated in relation to adjacent nerves, and MRA/MRV can identify the feeding artery and draining vein ( Table 2 ). Response to treatment can be reliably evaluated over time by changes in size and fl ow characteristics. 8,9 VTs include infantile haemangiomas (IHs), congenital haemangiomas (CHs) including non-involuting congenital haemangiomas (NICHs) and rapidly involuting congenital haemangiomas (RICHs), as well as kaposiform hae- mangioendotheliomas (KHEs), among others. Age of pre- sentation (prenatal, neonatal, early childhood/adult), presence or absence of overlying telangiectatic vessels, lighter peripheral ring, presence of high fl ow, and tem- poral evolution of the mass (involution, no involution) are important clinical criteria to approach diagnosis in VTs. Haemangiomas Infantile haemangioma IHs compromise approximately 90% of all VTs and are the most common VTs of infancy with higher incidence in the white Caucasian infants. The highest incidence is noted in the preterm infants weighing less than 1000 g. 10 The head and neck regions are involved most frequently (60% of cases), followed by the trunk (25% of cases), and extremities (15% of cases). 11 Vascular tumours

Table 1 Vascular anomalies (simpli fi ed and adapted from ISSVA 1996). Vascular tumours

Infantile haemangiomas Congenital haemangiomas

Rapidly involuting congenital haemangiomas Non-involuting congenital haemangiomas

Kaposiform haemangioendothelioma Others Vascular malformations Slow- fl ow vascular malformations Venous malformations Lymphatic malformations Capillary malformations Fast- fl ow vascular malformation Arteriovenous malformations/ fi stulas Combined complex vascular malformations Capillary e venous Capillary e arteriovenous Lymphaticovenous malformation

Glowacki in 1982. 2 This classi fi cation system divides VAs into two separate categories, vascular tumours (VTs) and vascular malformations (VaMs). 3 Congenital soft-tissue VAs can present anywhere in the body from head to toe, with variable size and in fi ltration; thus, a multidisciplinary approach is crucial in the management and treatment of these patients. Consistent use of correct terminology will improve communication between different specialists and avoid misunderstandings. Given the rarity of some of the VAs, and overlapping clinical and imaging features, experience of the team taking care of the patient is extremely important. The accurate classi fi cation and treatment of VAs is best performed by those groups who see a large volume of patients, and as a consequence can see the patterns of VAs in the clinical appearance coordinated with the imaging appearance. This is why the development of multidisciplinary VAs centres is essential for accurate diagnosis and management of these patients. In the present authors ’ clinical practice, we often see patients who say that their doctor had never seen anything like that before and had no idea what it was, let alone how to treat it. VAs can be imaged using ultrasonography (US), computed tomography (CT), CT angiography, digital

Table 2 Key magnetic resonance imaging features of vascular anomalies.

IH

VM LM

AVM

Solid mass Phlebolith

Yes

No

No No

No No

No

Yes

Enhancement Avid

Variable None (cysts ’

Avid serpiginous

homogeneous

periphery)

DCE-MRA

Arterial

Venous None

Arterial with early venous drainage

IH, infantile haemangioma; VM, venous malformation; LM, lymphatic mal- formation; AVM, arteriovenous malformation; DCE-MRA, dynamic contrast- enhanced magnetic resonance imaging.

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