Linear sign in cystic brain lesions ≥5 mm: A suggestive feature of perivascular space

Giant Tumefactive Perivascular Space: Advanced Fusion MR Imaging and Tractography Study-A Case Report and a Systematic Review

Perivascular spaces (PVSs) are small extensions of the subpial cerebrospinal space, pial-lined and interstitial fluid-filled. They surround small penetrating arteries, and veins, crossing the subarachnoid space to the brain tissue. Magnetic Resonance Imaging (MRI) shows a PVS as a round-shape or linear structure, isointense to the cerebrospinal fluid, and, if larger than 1.5 cm, they are known as giant/tumefactive PVSs (GTPVS) that may compress neighboring parenchymal/liquoral compartment. We report a rare asymptomatic case of GTPVS type 1 in a diabetic middle-aged patient, occasionally discovered. Our MRI study focuses on diffusion/tractography and fusion imaging: three-dimensional (3D) constructive interference in steady state (CISS) and time of fly (TOF) sequences. The advanced and fusion MR techniques help us to track brain fiber to assess brain tissue compression consequences and some PVS anatomic features as the perforating arteries inside them.

The landscape of brain tumor mimics in neuro-oncology practice

BACKGROUND AND OBJECTIVE

Differentiating neoplastic and non-neoplastic brain lesions is essential to make management recommendations and convey prognosis, but the distinction between brain tumors and their mimics in practice may prove challenging. The aim of this study is to provide the incidence of brain tumor mimics in the neuro-oncology setting and describe this patient subset.

METHODS

Retrospective study of adult patients referred to the Division of Neuro-oncology for a presumed diagnosis of brain tumor from January 1, 2005 through December 31, 2017, who later satisfied the diagnosis of a non-neoplastic entity based on neuroimaging, clinical course, and/or histopathology evaluation. We classified tumor mimic entities according to clinical, radiologic, and laboratory characteristics that correlated with the diagnosis.

RESULTS

The incidence of brain tumor mimics was 3.4% (132/3897). The etiologies of the non-neoplastic entities were vascular (35%), inflammatory non-demyelinating (26%), demyelinating (15%), cysts (10%), infectious (9%), and miscellaneous (5%). In our study, 38% of patients underwent biopsy to determine diagnosis, but in 26%, the biopsy was inconclusive.

DISCUSSION

Brain tumor mimics represent a small but important subset of the neuro-oncology referrals. Vascular, inflammatory, and demyelinating etiologies represent two-thirds of cases. Recognizing the clinical, radiologic and laboratory characteristics of such entities may improve resource utilization and prevent unnecessary as well as potentially harmful diagnostic and therapeutic interventions.

Aggravation of Enlarged Perivascular Spaces in the Centrum Semiovale of Patients with Aneurysmal Subarachnoid Hemorrhage

PURPOSE

This study aimed to investigate whether enlarged perivascular spaces (ePVS) within the basal ganglia (BG) or centrum semiovale (CSO) aggravate in patients with aneurysmal subarachnoid hemorrhage (aSAH).

METHODS

We retrospectively evaluated 139 patients who had undergone brain magnetic resonance imaging (MRI) within 1 month of aSAH occurrence from January 2007 to November 2018. Follow-up brain MRI of 99 patients were available. We scored ePVS in the BG and CSO on a score of 0-4 (0 = no ePVS, 4 ≥ 40 ePVS) on initial and follow-up T2-weighted MRI. Aggravation of ePVS was defined as an ePVS score increase of ≥ 1 on follow-up MRI compared to the initial score. We compared the characteristics between patients with and without aggravation of ePVS and investigated associated variables using logistic regression.

RESULTS

Aggravation of ePVS in the CSO and BG was noted in 31 (31.3%) and 6 (6.1%) patients, respectively. After adjusting for age, sex, and the MRI follow-up period, aggravation of ePVS in the CSO was independently associated with a high Fisher grade (p = 0.007) and high burden of initial ePVS in the CSO (p = 0.049).

CONCLUSION

Aggravation of ePVS, particularly those in the CSO, had occurred in the long-term follow-up of aSAH patients. This was independently associated with a high burden of aSAH. The amount of subarachnoid blood might have aggravated the drainage of interstitial fluid through glymphatic dysfunction.

Large anterior temporal Virchow–Robin spaces: Evaluating MRI features over the years—Our experience and literature review

Dilated Virchow–Robin spaces (VRSs) are expansions of the normal perivascular spaces with a short axis greater than 2 mm or, according to some authors, greater than 3 mm. They are usually documented at the basal ganglia, at the convexity white matter (WM) and centrum semiovale, and at the mesencephalon. The anterior temporal WM is a recently described preferential location for large (≥5 mm) VRSs. The aim of our study was to evaluate the magnetic resonance imaging (MRI) features and their modifications during a long-term follow-up period (≥24 months) of the anterior temporal VRSs with a retrospective analysis among all brain MRI studies performed at our institution between January 2010 and January 2017. In our study, the presence and the stability of characteristic MRI features certainly increased our diagnostic confidence allowing us to continue conservative approach while the surrounding signal change, as reported in the literature, should not in itself prompt alternative diagnoses to be entertained.