The retrobulbar "spot sign"--ocular sonography for the differential diagnosis of temporal arteritis and sudden blindness

Contribution of Orbital Ultrasound to the Diagnosis of Central Retinal Artery Occlusion

We aimed to evaluate the diagnostic value of orbital ultrasound in the etiologic diagnosis of central retinal artery occlusion (CRAO). For this purpose, patients with CRAO evaluated at our center between 2011 and 2021 were reviewed. Demographic variables, vascular risk factors and ultrasound findings were collected. An orbital duplex was performed in all cases and complemented with other diagnostic explorations. We attended 36 cases of CRAO. In all patients, orbital ultrasound confirmed the diagnosis of CRAO: in 75% emboli material (spot sign) was observed in CRA and in 25% flow alteration in CRA without visible embolus. The positive spot sign (PSS) group differed from patients with negative spot sign (NSS) in terms of etiology: 8 PSS cases (29.6%) had a major cardioembolic cause, 4 (14.8%) a large vessel atheromatous disease, 15 (55.6%) an undetermined cause. Some 21 (77.8%) PSS patients had some minor cardioembolic cause, mainly calcifications of the left valves. In the NSS group, 2 (22%) were diagnosed with giant cell arteritis (GCA). In CRAO, the ultrasound spot sign could be a guide for the detection of embolic sources. Its absence makes it necessary to consider more strongly the possibility of arteritis. Furthermore, our findings suggest a key role of calcium embolism in PSS patients.

Transocular sonography in acute arterial occlusions of the eye in elderly patients: Diagnostic value of the spot sign

PURPOSE

To characterize the diagnostic yield of the spot sign in the diagnostic workup of acute arterial occlusions of the eye in elderly patients.

METHODS

Clinical characteristics of consecutive patients aged ≥ 50 years with acute central retinal artery occlusion (CRAO), branch retinal artery occlusion (BRAO) or anterior ischemic optic neuropathy (AION) were recorded. Videos of transocular sonography were assessed for the presence of the spot sign by two blinded readers. Group comparisons were made between CRAO-patients with and without the spot sign. Two experienced cardiovascular physicians allocated CRAO-cases to a presumed aetiology, without and with knowledge on the presence/absence of the spot sign.

RESULTS

One-hundred-twenty-three patients were included, 46 of whom suffered from CRAO. A spot sign was seen in 32 of 46 of patients with CRAO and in 7 of 23 patients with BRAO. Interobserver agreement was excellent (Cohen`s kappa 0.98). CRAO-patients with the spot sign significantly more frequently had a medical history of cardiovascular disease (62.8 vs. 21.4%, p = 0.03) and left heart valve pathologies (51.9 vs. 10%, p = 0.03). The spot sign was not found in any of the three patients with CRAO secondary to cranial giant cell arteritis. The assumed CRAO aetiology differed in 37% of cases between two cardiovascular physicians, regardless whether transocular sonography findings were known or not.

CONCLUSION

The spot sign is a simple sonographic finding with excellent interobserver agreement, which proofs the embolic nature of CRAO, but does not allow exact attribution of the underlying aetiology.

[Retinal artery occlusion]

Retinal artery occlusion leads to profound visual impairment in the affected eye. It is rarely caused by local ophthalmic pathologies. Most patients present with a large number of cardio- and cerebrovascular risk factors. Visual loss is the leading symptom in central retinal artery occlusion (CRAO), whereas a circumscribed visual field defect is claimed in branch retinal artery occlusion (BRAO). Although many attempts have been made to improve the course of the disease, no effective therapy is available. There is some hope that intravenous fibrinolysis could influence the natural course but the therapeutic window is small (ca. 4.5 h), and treatment efficacy is still not proven. It is important for ophthalmologists to guide the patients to a comprehensive and prompt neurological and cardiological diagnostic work-up.