What is Dolichoectasia?
Dolichoectasia is a rare cerebrovascular disorder characterized by abnormal fusiform dilatation, elongation, and tortuosity of cerebral arteries, most commonly affecting the vertebrobasilar system. 1
Pathological Characteristics
- The term "fusiform" describes the shape of these dilated vessels, distinguishing them from saccular aneurysms 1
- Dolichoectatic arteries have an abnormally large external diameter with a thin arterial wall, featuring degeneration of the internal elastic lamina, multiple gaps in the internal elastica, thinning of the media secondary to reticular fiber deficiency, and smooth muscle atrophy 2
- Activation of metalloproteinases and irregular turbulent blood flow cause irreversible disruption of the internal elastic lamina 3
Vascular Distribution
- The intracranial vertebral and basilar arteries (posterior circulation) are preferentially involved 2, 3
- While less common, dolichoectasia can also affect the anterior circulation, including the internal carotid arteries 4
- Having dolichoectasia of both posterior and anterior circulation simultaneously is extremely rare 4
Clinical Manifestations
The clinical presentations fall into three major categories:
- Acute brain ischemia: Flow in dilated arteries can become bidirectional, resulting in reduced antegrade flow and thrombus formation 2
- Progressive neurological deficits: Compression of cranial nerves, the brain stem, or the third ventricle can cause cranial neuropathies and hydrocephalus 2, 4
- Catastrophic hemorrhagic events: Vascular rupture can occur due to arterial wall degeneration 2, 5
- Elongation and angulation of arteries can stretch and distort the orifices of arterial branches, leading to decreased blood flow, especially in penetrating branches 2
Risk Factors and Epidemiology
- Traditional cardiovascular risk factors, including hypertension and male sex, are strongly associated with dolichoectasia 1
- The prevalence of dolichoectasia increases with age 3
- The relationship to atherosclerotic disease remains unclear, though both conditions may coexist 1
Diagnostic Approach
- Diagnosis requires visual assessment of vessel shape on imaging 3
- For posterior circulation involvement, apply Smoker's criteria for objective diagnosis 3
- Imaging should document vessel diameter, degree of tortuosity, and presence of associated complications like thrombus or mass effect 1
- Reproducible criteria for diagnosing anterior circulation dolichoectasia are lacking, making diagnosis more challenging in these cases 3, 6