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OBJECTIVES: Developing new high relaxivity gadolinium-based contrast agents (GBCAs) for magnetic resonance imaging (MRI) allowing dose reduction while maintaining similar diagnostic efficacy is needed, especially in the context of gadolinium retention in tissues. This study aimed to demonstrate that contrast-enhanced MRI of the central nervous system (CNS) with gadopiclenol at 0.05 mmol/kg is not inferior to gadobutrol at 0.1 mmol/kg, and superior to unenhanced MRI. MATERIALS AND METHODS: PICTURE is an international, randomized, double-blinded, controlled, cross-over, phase III study, conducted between June 2019 and September 2020. Adult patients with CNS lesions were randomized to undergo 2 MRIs (interval, 2-14 days) with gadopiclenol (0.05 mmol/kg) then gadobutrol (0.1 mmol/kg) or vice versa. The primary criterion was lesion visualization based on 3 parameters (border delineation, internal morphology, and contrast enhancement), assessed by 3 off-site blinded readers. Key secondary outcomes included lesion-to-background ratio, enhancement percentage, contrast-to-noise ratio, overall diagnostic preference, and adverse events. RESULTS: Of the 256 randomized patients, 250 received at least 1 GBCA administration (mean [SD] age, 57.2 [13.8] years; 53.6% women). The statistical noninferiority of gadopiclenol (0.05 mmol/kg) to gadobutrol (0.1 mmol/kg) was achieved for all parameters and all readers (n = 236, lower limit 95% confidence interval of the difference ≥-0.06, above the noninferiority margin [-0.35], P < 0.0001), as well as its statistical superiority over unenhanced images (n = 239, lower limit 95% confidence interval of the difference ≥1.29, P < 0.0001).Enhancement percentage and lesion-to-background ratio were higher with gadopiclenol for all readers ( P < 0.0001), and contrast-to-noise ratio was higher for 2 readers ( P = 0.02 and P < 0.0001). Three blinded readers preferred images with gadopiclenol for 44.8%, 54.4%, and 57.3% of evaluations, reported no preference for 40.7%, 21.6%, and 23.2%, and preferred images with gadobutrol for 14.5%, 24.1%, and 19.5% ( P < 0.001).Adverse events reported after MRI were similar for gadopiclenol (14.6% of patients) and gadobutrol (17.6%). Adverse events considered related to gadopiclenol (4.9%) and gadobutrol (6.9%) were mainly injection site reactions, and none was serious. CONCLUSIONS: Gadopiclenol at 0.05 mmol/kg is not inferior to gadobutrol at 0.1 mmol/kg for MRI of the CNS, confirming that gadopiclenol can be used at half the gadolinium dose used for other GBCAs to achieve similar clinical efficacy.

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Epilepsy is among one of the most common neurologic disorders. The role of magnetic resonance imaging (MRI) in the diagnosis and management of patients with epilepsy is well established, and most patients with epilepsy are likely to undergo at least one or more MRI examinations in the course of their disease. Recent advances in high-field MRI have enabled high resolution in vivo visualization of small and intricate anatomic structures that are of great importance in the assessment of seizure disorders. Familiarity with normal anatomic variations is essential in the accurate diagnosis and image interpretation, as these variations may be mistaken for epileptogenic foci, leading to unnecessary follow-up imaging, or worse, unnecessary treatment. After a brief overview of normal imaging anatomy of the mesial temporal lobe, this article will review a few important common and uncommon anatomic variations, mimics, and pitfalls that may be encountered in the imaging evaluation of patients with epilepsy.

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The purpose of this systematic review is to identify trends and extent of variability in intracranial vessel wall MR imaging (VWI) techniques and protocols. Although variability in selection of protocol design and pulse sequence type is known, data on what and how protocols vary are unknown. Three databases were searched to identify publications using intracranial VWI. Publications were screened by predetermined inclusion/exclusion criteria. Technical development publications were scored for completeness of reporting using a modified Nature Reporting Summary Guideline to assess reproducibility. From 2,431 articles, 122 met the inclusion criteria. Trends over the last 23 years (1995-2018) show increased use of 3-Tesla MR (P < .001) and 3D volumetric T1-weighted acquisitions (P < .001). Most (65%) clinical VWI publications report achieving a noninterpolated in-plane spatial resolution of ≤.55 mm. In the last decade, an increasing number of technical development (n = 20) and 7 Tesla (n = 12) publications have been published, focused on pulse sequence development, improving cerebrospinal fluid suppression, scan efficiency, and imaging ex vivo specimen for histologic validation. Mean Reporting Summary Score for the technical development publications was high (.87, range: .63-1.0) indicating strong scientific technical reproducibility. Innovative work continues to emerge to address implementation challenges. Gradual adoption into the research and scientific community was suggested by a shift in the name in the literature from "high-resolution MR" to "vessel wall imaging," specifying diagnostic intent. Insight into current practices and identifying the extent of technical variability in the literature will help to direct future clinical and technical efforts to address needs for implementation.

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Variations in the venous drainage of the central nervous system can have imaging and clinical findings that mimic pathology, presenting a challenge for neuroimagers and clinicians. Patients with these variants may undergo unnecessary testing, and patients with pathology may receive delayed diagnoses because of overlap with benign findings. Consequently, the accurate identification of venous variations on cross-sectional imaging and angiography and their potential causes are critical for differentiating benign imaging variants from potential pathologic processes requiring further evaluation. For example, in the epidural space, benign dilation of the epidural venous plexus may be mistaken for evidence of a fistula, abscess, or metastasis. Hypoplasia of a dural venous sinus or an arachnoid granulation may mimic venous sinus thrombosis. The superior ophthalmic vein may demonstrate benign dilation in intubated patients, mimicking thrombosis, increased intracranial pressure, orbital varix, inflammatory pseudotumor, or other conditions. Furthermore, certain venous variations, such as the occipital sinus or emissary veins, may complicate surgery or herald pathology and should be reported. In addition, some supposedly benign variations, such as the developmental venous anomaly, can be complicated by pathology. The objective of this review article is to provide a descriptive and pictorial review of common anatomic and physiologic variations in the venous drainage system of the brain, spine, and orbits that can mimic pathology. Neuroimaging findings of related pathologies and differences in clinical presentations will also be discussed to assist in the approach to differential diagnosis.

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Wallerian degeneration (WD) is defined as progressive anterograde disintegration of axons and accompanying demyelination after an injury to the proximal axon or cell body. Since the 1980s and 1990s, conventional magnetic resonance imaging (MRI) sequences have been shown to be sensitive to changes of WD in the subacute to chronic phases. More recently, advanced MRI techniques, such as diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI), have demonstrated some of earliest changes attributed to acute WD, typically on the order of days. In addition, there is increasing evidence on the value of advanced MRI techniques in providing important prognostic information related to WD. This article reviews the utility of conventional and advanced MRI techniques for assessing WD, by focusing not only on the corticospinal tract but also other neural tracts less commonly thought of, including corticopontocerebellar tract, dentate-rubro-olivary pathway, posterior column of the spinal cord, corpus callosum, limbic circuit, and optic pathway. The basic anatomy of these neural pathways will be discussed, followed by a comprehensive review of existing literature supported by instructive clinical examples. The goal of this review is for readers to become more familiar with both conventional and advanced MRI findings of WD involving important neural pathways, as well as to illustrate increasing utility of advanced MRI techniques in providing important prognostic information for various pathologies.

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BACKGROUND AND PURPOSE: Hyperintensity on T1-weighted imaging in perilesional vasogenic edema has been reported as a useful sign for differentiating cavernous malformation from other hemorrhagic intra-axial masses. In this study, we investigated the frequency of perilesional hyperintensity on T1-weighted imaging in patients with intra-axial hemorrhagic and nonhemorrhagic brain masses. METHODS: The study was performed with the approval of the institutional review board. Magnetic resonance images of 218 patients with 282 intra-axial brain masses (129 metastases, 46 gliomas, 18 primary central nervous system lymphomas [PCNSLs], 25 intracerebral hemorrhages, 50 cavernous malformations, and 14 patients with brain abscesses) were evaluated. The signal intensity in perilesional area was qualitatively evaluated on T1-weighted sequences. In addition, signal intensity in perilesional area was quantitatively measured on T1-weighted sequences and normalized to the contralateral white matter. RESULTS: Hyperintensity on T1-weighted imaging in perilesional vasogenic edema was found in 12 (9%) of 129 metastases, 8 (16%) of 50 cavernous malformations, 1 (4%) in 25 nonneoplastic intracerebral hemorrhages, and none of the patients with high-grade glioma, PCNSL, or abscess. All of the lesions with perilesional hyperintensity showed either acute or subacute hemorrhage. Pairwise comparison of qualitative hyperintensity on T1-weighted imaging demonstrated no significant difference between the groups. Perilesional hyperintensity on T1-weighted imaging showed high specificity in both metastasis and cavernous malformation groups (94%). CONCLUSION: Perilesional hyperintensity on T1-weighted imaging is not limited to cavernous malformations and frequently evident with melanoma and other hemorrhagic metastasis to the brain. In our experience, it was not seen in high-grade glioma, PCNSL, and brain abscess.

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Developmental venous anomalies (DVAs) are the most common cerebral vascular malformations and are usually found incidentally on neuroimaging studies. Despite the benign nature of DVAs, occasionally, they can be symptomatic. The objective of this article is to review the spectrum of imaging findings of DVAs on conventional and advanced imaging studies. In addition, neuroimaging findings of symptomatic DVAs as well as imaging mimicks will also be described to assist in the approach to differential diagnosis.

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Abstract: Dural metastases are an unusual form of spread in treated sinonasal malignancies. An analysis is presented of 20 cases of dural metastases diagnosed during imaging follow-up in a selection of cases in which anterior craniofacial resection was performed. They included 12 undifferentiated sinonasal carcinomas, 7 olfactory neuroblastomas, and 1 adenoid cystic carcinoma case. Dural metastases appeared on an average of 7.3 years after treatment in olfactory neuroblastoma. The maximum distance from malignancy to dural metastases was 14 cm for olfactory neuroblastoma, and 4.3 cm for undifferentiated sinonasal carcinoma. Dural metastases in the Burr holes were observed in 50% of undifferentiated sinonasal carcinoma, and 29% of olfactory neuroblastomas. Dural metastases presented as a nodular (60%), multinodular (10%), cystic (15%), and plaque (15%) pattern. These are suggestive of a local venous spread mechanism related to tumour rupture during surgery of anterior cranial fossa. Long-term follow-up with cranial inclusion would be indicated, given the possible late and distant presentation of dural metastases.

Resumen: Presentamos las metástasis durales como forma inusual de diseminación de tumores nasosinusales malignos tratados; se revisan 20 casos diagnosticados durante el seguimiento imagenológico a un grupo tratado con resección craneofacial anterior. Evaluamos metástasis durales en 12 carcinomas nasosinusales indiferenciados, 7 neuroblastomas olfatorios y un carcinoma adenoquístico. En neuroblastomas olfatorios aparecieron metástasis durales en promedio 7,3 años postratamiento. La distancia máxima del tumor a la metástasis fue de 14 cm para neuroblastoma olfatorio y de 4,3 cm para carcinoma nasosinusal indiferenciado. Observamos metástasis durales en los agujeros de trepanación en el 50% de los carcinomas nasosinusales indiferenciados y en el 29% de los neuroblastomas olfatorios. Las metástasis durales presentaron patrón nodular (60%), multinodular (10%), quístico (15%) y en placa (15%). Proponemos un mecanismo venoso local de diseminación relacionado a disrupción tumoral o quirúrgica de la fosa craneal anterior. El seguimiento a largo plazo con inclusión craneal estaría indicado por la posible presentación tardía y distante de metástasis durales.

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