Advanced multiparametric magnetic resonance imaging of multinodular and vacuolating neuronal tumor

BACKGROUND AND PURPOSE

Multinodular and vacuolating neuronal tumor (MVNT) of the cerebrum is a rare brain lesion with suggestive imaging features. The aim of our study was to report the largest series of MVNTs so far and to evaluate the utility of advanced multiparametric magnetic resonance (MR) techniques.

METHODS

This multicenter retrospective study was approved by our institutional research ethics board. From July 2014 to May 2019, two radiologists read in consensus the MR examinations of patients presenting with a lesion suggestive of an MVNT. They analyzed the lesions' MR characteristics on structural images and advanced multiparametric MR imaging.

RESULTS

A total of 64 patients (29 women and 35 men, mean age 44.2 ± 15.1 years) from 25 centers were included. Lesions were all hyperintense on fluid-attenuated inversion recovery and T2-weighted imaging without post-contrast enhancement. The median relative apparent diffusion coefficient on diffusion-weighted imaging was 1.13 [interquartile range (IQR), 0.2]. Perfusion-weighted imaging showed no increase in perfusion, with a relative cerebral blood volume of 1.02 (IQR, 0.05) and a relative cerebral blood flow of 1.01 (IQR, 0.08). MR spectroscopy showed no abnormal peaks. Median follow-up was 2 (IQR, 1.2) years, without any changes in size.

CONCLUSIONS

A comprehensive characterization protocol including advanced multiparametric magnetic resonance imaging sequences showed no imaging patterns suggestive of malignancy in MVNTs. It might be useful to better characterize MVNTs.

Multinodular and Vacuolating Posterior Fossa Lesions of Unknown Significance

Multinodular and vacuolating neuronal tumor of the cerebrum is a rare supratentorial brain tumor described for the first time in 2013. Here, we report 11 cases of infratentorial lesions showing similar striking imaging features consisting of a cluster of low T1-weighted imaging and high T2-FLAIR signal intensity nodules, which we referred to as multinodular and vacuolating posterior fossa lesions of unknown significance. No relationship was found between the location of the lesion and clinical symptoms. A T2-FLAIR hypointense central dot sign was present in images of 9/11 (82%) patients. Cortical involvement was present in 2/11 (18%) of patients. Only 1 nodule of 1 multinodular and vacuolating posterior fossa lesion of unknown significance showed enhancement on postcontrast T1WI. DWI, SWI, MRS, and PWI showed no malignant pattern. Lesions did not change in size or signal during a median follow-up of 3 years, suggesting that multinodular and vacuolating posterior fossa lesions of unknown significance are benign malformative lesions that do not require surgical intervention or removal.

TIPIC Syndrome: Beyond the Myth of Carotidynia, a New Distinct Unclassified Entity

BACKGROUND AND PURPOSE

The differential diagnosis of acute cervical pain includes nonvascular and vascular causes such as carotid dissection, carotid occlusion, or vasculitis. However, some patients present with unclassified vascular and perivascular changes on imaging previously reported as carotidynia. The aim of our study was to improve the description of this as yet unclassified clinico-radiologic entity.

MATERIALS AND METHODS

From January 2009 through April 2016, 47 patients from 10 centers presenting with acute neck pain or tenderness and at least 1 cervical image showing unclassified carotid abnormalities were included. We conducted a systematic, retrospective study of their medical charts and diagnostic and follow-up imaging. Two neuroradiologists independently analyzed the blinded image datasets.

RESULTS

The median patient age was 48 years. All patients presented with acute neck pain, and 8 presented with transient neurologic symptoms. Imaging showed an eccentric pericarotidian infiltration in all patients. An intimal soft plaque was noted in 16 patients, and a mild luminal narrowing was noted in 16 patients. Interreader reproducibility was excellent. All patients had complete pain resolution within a median of 13 days. At 3-month follow-up, imaging showed complete disappearance of vascular abnormalities in 8 patients, and a marked decrease in all others.

CONCLUSIONS

Our study improved the description of an unclassified, clinico-radiologic entity, which could be described by the proposed acronym: TransIent Perivascular Inflammation of the Carotid artery (TIPIC) syndrome.

[Color Doppler imaging and central retinal artery occlusion]

PURPOSE

To assess the role of CDI of retrobulbar vessels in pathogenic diagnosis of CRAO.

METHODS

We have used a sonographer with 9 MHz linear probe.

RESULTS

We present four patients with CRAO that have no emboli visible on ophthalmoscopy The first patient had no blood flow signal on CDI on a surface of 2 millimeters behind the optic disc. B-scan ultrasound evaluation found a small round, moderate reflective echo within the optic nerve, 2 millimeters behind the optic disc. Carotid ultrasound examination found an ulcerated ateromatous plaque, as being the source of cholesterol emboli. The second patient had no detectable flow in central retinal artery due to multiple reverberations determined by calcic arterial emboli, placed 5 millimeters behind the optic disc. The chest X-ray showed an aortic plaque, considered the source of the emboli. The third patient had characteristic CDI findings for Horton disease: low blood velocities and high resistance index in all retrobulbar vessels, in both orbits. The diagnosis was sustained by carotid ultrasound. The last patient had a very low blood flow velocity in CRA, due to acute carotid occlusion.

CONCLUSIONS

Ultrasound investigation is a valuable diagnostic tool for identifying potential systemic conditions associated with CRAO.

[Giant cell arteritis with eye involvment--color Doppler imaging or retrobulabar vessels findings]

BACKGROUND

Giant cell arteritis (temporal arteritis) is a primary vasculitis, that affects large arteries, especially branches of the external carotid artery (ECA).

PURPOSE

To assess the role of CDI of retrobulbar vessels in the study of two patients with giant cell arteritis with eye involvement.

METHODS

We have used a sonographer with 8-15 MHz linear probe.

RESULTS

Both patients presented malaise, temporal headache, tender temporal arteries and signs of inflammation. The first patient had a central retinal artery obstruction of the right eye, and the second had anterior ischaemic optic neuropathy of the left eye. Temporal artery histology was positive in both cases. Ultrasound investigation was performed within the first 10 days of corticosteroid treatment. CDI of retrobulbar vessels detected low blood velocities, especially end-diastolic velocities and high resistance index in all retrobulbar vessels, in both orbits. Typical sonographic features in temporal arteritis were "halo", associated with stenoses or occlusions of branches of ECA.

CONCLUSIONS

Ultrasound investigation is a valuable diagnostic tool to investigate giant cell arteritis.

[Carotid-cavernous fistulas of low-flow type: color Doppler imaging of retrobulbar vessels findings]

BACKGROUND

Carotid-cavernous fistulas (CCF) of low-flow type are the results of development of communication between small arteries and veins of cavernous sinus.

PURPOSE

To assess the role of CDI of retrobulbar vessels in the study of two patients with CCF of low-flow type.

METHODS

We have used a sonographer with 9MHz linear probe.

RESULTS

. The initial diagnosis was suspected clinically: both patients presented unilateral chemosis and orbital bruit. It was sustained by CDI of retrobulbar vessels: reversed flow in the superior ophthalmic vein, with a venous arterialisation and confirmed with complete selective digital substraction angiography, which is essential for a correct diagnosis(early opacification of veins draining cavernous sinus, etc).

CONCLUSIONS

CDI of retrobulbar vessels is a repetitive non-invasive technique, which is used for monitoring carotid-cavernous fistulas of low-flow type, because they are sometimes a self-limiting pathology (spontaneous venous thrombosis).