PMC9560574_01
Frontal projection left frontal internal carotid artery 3D DSA demonstrates a giant terminal internal carotid artery aneurysm (a). T2W axial MR images 6 months (b,c), 18 months (d,e), 21 months (f), 27 months (g), 36 months (h), 51 months (i,j) and 119 months (k) after embolisation demonstrate development of progressive oedema and progressive enlargement of cystic spaces.
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A 61-year-old woman was found to have an incidental 20 mm left terminal internal carotid artery (ICA) aneurysm (Fig. 1a). Routine 6-month follow-up cranial MRI, demonstrated a small amount of surrounding oedema around the coiled aneurysm (Fig. 1b and c). Repeat MRI one year later revealed an increasing amount of perianeurysmal oedema as well as further aneurysmal growth (Fig. 1d and e).
PMC9560574_02
Frontal projection of a left internal carotid angiogram (a) demonstrates a large terminal internal carotid artery aneurysm. Axial unenhanced cranial CT scans (b,c), the day after embolisation, show a small amount of oedema in the left basal ganglia.. T2W axial MR images one month (d,e), 12 months (f,g,h) and 33 months after embolisation (i,j,k) show progressive oedema, development and enlargement of the perinaneurysmal cysts.
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A 68-year-old man was referred with an incidental 21 mm left terminal ICA aneurysm, that was treated with endovascular coiling (Fig. 2a). One day post coiling a cranial CT demonstrated some oedema superior to the coiled aneurysm (Fig. 2b and c). Follow-up cranial MRI at 1 month revealed persistent reactive oedema around the coiled aneurysm (Fig. 2d and e) which did not seem to respond to a trial of dexamethasone and nonsteroidal anti-inflammatory agents (NSAIDs). With the progression of oedema, a small cystic lesion with a diameter of 10.5 mm developed adjacent to the aneurysm and enlarged 12-33 months after embolisation (Fig. 2f-k) achieving a diameter of 3.3 cm.
PMC9560574_03
Frontal projection left internal carotid angiogram demonstrating the giant bifurcation left middle cerebral artery aneurysm (a), axial unenhanced cranial CT scan pre-embolisation demonstrating the aneurysm without associated oedema or cyst formation (b), and T2W axial MR images 6 months post embolisation (c,d,e), demonstrating the development of oedema in the left temporal lobe, deep to the insula and in the posterior limb of the left internal capsule and optic radiations. Axial T2W MR images at 14 months post embolisation (f,g,h), show some increase in oedema and enlargement of the cyst, 21 (i,j) and 27 (k) months post embolisation and 33 (l,m) months post embolisation, demonstrate further significant cyst enlargement with increasing oedema (i,j,k) and decrease in both oedema and cyst volume post shunt insertion (l,m). There has also been progressive ventricular enlargement, the result of a communicating hydrocephalus.
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A 75-year-old lady was referred with a large partly-thrombosed left middle cerebral artery bifurcation aneurysm, measuring 21 mm (Fig. 3a and b), identified on imaging to investigate an episode of collapse and speech disturbance. These follow-up MRI scans also revealed a significant amount of perianeurysmal oedema around the treated aneurysm, with the MR angiogram revealing a 14 mm associated cyst (Fig. 3c,d,e). The cyst expanded, measuring up to 44 mm and 50 mm at 4 and 6 months later respectively, once again in association with considerable surrounding oedema (Fig. 3f-k). She had further intervention 3 months later with the insertion of an access device and serial aspirations that resulted in symptomatic improvement and radiological volume reduction (Fig. 3 l,m).