Ultrasound Contrast Agent Needle Priming: Impact on Sonographic Biopsy Needle Visibility in a Porcine Liver Model.

PURPOSE: The visibility of biopsy needles in contrast-specific imaging mode can be improved by priming them with an ultrasound contrast agent (previously demonstrated in a phantom model/ex vivo). The purpose of this study was to validate this priming method in a porcine in vivo model. MATERIALS AND METHODS: Using a small syringe, full-core biopsy needles were primed with sulfur hexafluoride, an ultrasound contrast agent, with non-primed needles serving as controls (n = 30 + 30). Liver punctures were performed in a porcine model following intravenous administration of the same ultrasound contrast agent. Needle visibility, both in their entirety and at the tips, was evaluated in split-screen mode using contrast-specific imaging and B-mode (low mechanical index). The assessment included quantitative analysis, calculating the contrast-to-noise ratio, and qualitative evaluation through structured grading by three radiologists. RESULTS: After needle priming, the contrast-to-noise ratio was superior for the needle in its entirety in contrast-specific imaging mode (p < 0.001) and slightly inferior in B-mode (p = 0.008). No differences were observed for the needle tips in either imaging mode. Qualitatively, the needle visibility was deemed clinically superior after needle priming throughout in contrast-specific imaging mode (p < 0.001), whereas no clinically relevant differences in B-mode for either the needle in its entirety (p = 0.11) or the needle tip (p = 1) were observed. CONCLUSION: In this in vivo porcine liver model experiment, priming biopsy needles with ultrasound contrast agent improved needle visibility in contrast-specific imaging mode but slightly reduced it in B-mode. These findings support the method's use for biopsies requiring target visualization in contrast-specific imaging mode.

Ablative or Surgical Treatment for Small Renal Masses (T1a): A Single-Center Comparison of Perioperative Morbidity and Complications.

The purpose of this study is to evaluate the treatment safety of thermal ablation compared to surgical treatment of T1a tumors (small renal masses) at a high-volume center. We conducted an observational single-center study based on data collected form the National Swedish Kidney Cancer Register (NSKCR) between 2015 and 2021. In total, 444 treatments of T1a tumors were included. Patients underwent surgery (partial or total nephrectomy) or ablative treatment-radiofrequency ablation (RFA) or microwave ablation (MWA). Patient characteristics were retrieved from patient records, and tumor complexity was estimated from pre-interventional CT scans. The odds ratio (OR) of suffering from a severe surgical complication following ablative treatment was estimated using a logistic regression model adjusted for age, BMI, ASA physical status classification, smoking status and RENAL nephrometry score. The frequency of severe surgical complications was 6.3% (16/256 treatments) after surgical intervention and 2.1% (4/188 treatments) following ablative treatment. Our primary hypothesis that ablative treatment is associated with a lower risk of severe surgical complications is supported by the results (OR 0.39; 0.19-0.79; p = 0.013). When adjusting for age, smoking status, ASA score, BMI score and RENAL nephrometry score, we see an even greater difference between the two groups (OR 0.34; 0.17-0.68; p = 0.002). Our study was limited by the differences in patient and tumor characteristics between the two compared groups and the study design. If oncological outcomes are found to be comparable, ablative treatment should be considered as a first-line treatment for all small renal masses.

MRI detection of brain gadolinium retention in multiple sclerosis: Magnetization transfer vs. T1-weighted imaging.

BACKGROUND AND PURPOSE: Evidence of brain gadolinium retention has affected gadolinium-based contrast agent usage. It is, however, unclear to what extent macrocyclic agents are retained and whether their in vivo detection may necessitate nonconventional MRI. Magnetization transfer (MT) could prove suitable to detect gadolinium-related signal changes since dechelated gadolinium ions bind to macromolecules. Therefore, this study aimed to investigate associations of prior gadolinium administrations with MT and T1 signal abnormalities. METHODS: A cohort of 23 persons with multiple sclerosis (MS) (18 females, 5 males, 57 ± 8.0 years) with multiple past gadolinium administrations (median 6, range 3-12) and 23 age- and sex-matched healthy controls underwent 1.5 Tesla MRI with MT, T1-weighted 2-dimensional spin echo, and T1-weighted 3-dimensional gradient echo. The signal intensity index was assessed by MRI in gadolinium retention predilection sites. RESULTS: There were dose-dependent associations of the globus pallidus signal on gradient echo (r = .55, p < .001) and spin echo (r = .38, p = .013) T1-weighted imaging, but not on MT. Relative to controls, MS patients had higher signal intensity index in the dentate nucleus on T1-weighted gradient echo (1.037 ± 0.040 vs. 1.016 ± 0.023, p = .04) with a similar trend in the globus pallidus on T1-weighted spin echo (1.091 ± 0.034 vs. 1.076 ± 0.014, p = .06). MT detected no group differences. CONCLUSIONS: Conventional T1-weighted imaging provided dose-dependent associations with gadolinium administrations in MS, while these could not be detected with 2-dimensional MT. Future studies could explore newer MT techniques like 3D and inhomogenous MT. Notably, these associations were identified with conventional MRI even though most patients had not received gadolinium administrations in the preceding 9 years, suggestive of long-term retention.

Validation of Rapid Magnetic Resonance Myelin Imaging in Multiple Sclerosis.

OBJECTIVE: Magnetic resonance imaging (MRI) is essential for multiple sclerosis diagnostics but is conventionally not specific to demyelination. Myelin imaging is often hampered by long scanning times, complex postprocessing, or lack of clinical approval. This study aimed to assess the specificity, robustness, and clinical value of Rapid Estimation of Myelin for Diagnostic Imaging, a new myelin imaging technique based on time-efficient simultaneous T1 /T2 relaxometry and proton density mapping in multiple sclerosis. METHODS: Rapid myelin imaging was applied using 3T MRI ex vivo in 3 multiple sclerosis brain samples and in vivo in a prospective cohort of 71 multiple sclerosis patients and 21 age/sex-matched healthy controls, with scan-rescan repeatability in a subcohort. Disability in patients was assessed by the Expanded Disability Status Scale and the Symbol Digit Modalities Test at baseline and 2-year follow-up. RESULTS: Rapid myelin imaging correlated with myelin-related stains (proteolipid protein immunostaining and Luxol fast blue) and demonstrated good precision. Multiple sclerosis patients had, relative to controls, lower normalized whole-brain and normal-appearing white matter myelin fractions, which correlated with baseline cognitive and physical disability. Longitudinally, these myelin fractions correlated with follow-up physical disability, even with correction for baseline disability. INTERPRETATION: Rapid Estimation of Myelin for Diagnostic Imaging provides robust myelin quantification that detects diffuse demyelination in normal-appearing tissue in multiple sclerosis, which is associated with both cognitive and clinical disability. Because the technique is fast, with automatic postprocessing and US Food and Drug Administration/CE clinical approval, it can be a clinically feasible biomarker that may be suitable to monitor myelin dynamics and evaluate treatments aiming at remyelination. ANN NEUROL 2020;87:710-724.

Successful combined targeting of B- and plasma cells in treatment refractory anti-NMDAR encephalitis.

We describe an extremely severe case of therapy refractory NMDA receptor encephalitis (NMDAe) in a 26-year-old woman. After rituximab, bilateral oophorectomy, repeated cycles of high dose methylprednisolone and plasma exchange, she received repeated cyclophosphamide, tocilizumab (interleukin-6 inhibitor) and finally bortezomib (plasma cell depleting drug) leading to remission after 204days in intensive care. Two years after disease onset her cognitive functions are still affected, but slowly improving and the cerebral atrophy has been partly reversed. The cerebrospinal fluid biomarker profile suggests an early synaptic/dendritic process, with subsequent neuroaxonal degeneration motivating aggressive treatment early on.

Cortical superficial siderosis: Prevalence and biomarker profile in a memory clinic population.

OBJECTIVE: To gain further insight into cortical superficial siderosis (cSS), a new hemorrhagic neuroimaging marker of cerebral amyloid angiopathy (CAA), and to investigate the clinical, neuroimaging, genetic, and CSF biomarker profile of cSS in a large, consecutive memory clinic series. METHODS: We included 1,504 memory clinic patients undergoing dementia investigation including a brain MRI in our center. Routine CSF biomarker analysis was performed in 1,039 patients and APOE genotyping in 520 patients. MRIs were systematically evaluated for presumed marker of small vessel disease: cSS, cerebral microbleeds, enlarged perivascular spaces, white matter hyperintensities, and lacunes. RESULTS: cSS was detected in 40 patients (2.7%; 95% confidence interval [CI] 1.9-3.6); cSS was focal in 33 cases (2.2%; 95% CI 1.5-3.1) and disseminated in 7 (0.5%; 95% CI 0.2-1). Vascular dementia had the highest cSS prevalence (13%; 95% CI 5.4-24.9), followed by Alzheimer disease (5%; 95% CI 3.1-7.5). The most commonly affected area was the occipital lobe (70%; 95% CI 53.5-83.4). cSS was associated with lobar cerebral microbleeds (odds ratio [OR] 7.9; 95% CI 3.4-18.1; p < 0.001), high-degree centrum semiovale perivascular spaces (OR 1.7; 95% CI 1.2-2.6; p = 0.008), and white matter hyperintensities (OR 1.5; 95% CI 1.0-2.2; p = 0.062). APOE ε4/4 genotype was more common in cSS cases compared to those without. CSF ß-amyloid 42 was lower in patients with cSS (coefficient -0.09; 95% CI -0.15 to -0.03; p = 0.004). CONCLUSIONS: Our large series of memory clinic patients provides evidence that cSS is related to cerebrovascular disease and may be a manifestation of severe CAA, even in patients without intracerebral hemorrhage.