AJNR. American journal of neuroradiology最新文献

With full FDA approval and Centers for Medicare & Medicaid Services coverage of lecanemab and donanemab, a growing number of practices are offering anti-amyloid immunotherapy to appropriate patients with cognitive impairment or mild dementia due to amyloid-positive Alzheimer disease. The goal of this article is to provide updated practical considerations for radiologists, including implementation of MR imaging protocols, workflows, and reporting and communication practices relevant to anti-amyloid immunotherapy and monitoring for amyloid-related imaging abnormalities (ARIA). On the basis of consensus discussion within an expanded American Society of Neuroradiology (ASNR) Alzheimer, ARIA, and Dementia Study Group, our purpose is the following: 1) summarize the FDA guidelines for the evaluation of radiographic ARIA; 2) review the 3 key MRI sequences for ARIA monitoring and standardized imaging protocols on the basis of ASNR-industry collaborations; 3) provide imaging recommendations for 3 key patient scenarios; 4) highlight the role of the radiologist in the care team for this population; 5) discuss implementation of MRI protocols to detect ARIA in diverse practice settings; and 6) present the results of the 2023 ASNR international neuroradiologist practice survey on dementia and ARIA imaging.

Background and purpose: Differentiating radiation necrosis (RN) from tumor progression (TP) after radiation therapy for brain metastases is an important clinical problem requiring advanced imaging techniques that may not be widely available and are challenging to perform at multiple time points. The ability to leverage conventional MRI for this problem could have a meaningful clinical impact. The purpose of this study was to explore contrast-enhanced T2 FLAIR (T2FLAIRc) as a new imaging biomarker of RN and TP.

Materials and methods: This single-institution retrospective study included patients with treated brain metastases undergoing DSC-MRI between January 2021 and June 2023. Reference standard assessment was based on histopathology or serial follow-up, including the results of DSC-MRI for a minimum of 6 months from the first DSC-MRI. The index test was implemented as part of the institutional brain tumor MRI protocol and preceded the first DSC-MRI. T2FLAIRc and gadolinium-enhanced T1 (T1c) MPRAGE signal were normalized against normal brain parenchyma and expressed as a z score. The mean signal intensity of enhancing disease for the RN and TP groups was compared using an unpaired t test. Receiver operating characteristic curves and area under the receiver operating characteristic curve (AUC) were derived by bootstrapping. The DeLong test was used to compare AUCs.

Results: Fifty-six participants (mean age, 62 [SD, 12.7] years; 39 women; 28 with RN, 28 with TP) were evaluated. The index MRI was performed, on average, 73 [SD, 34] days before the first DSC-MRI. Significantly higher z scores were found for RN using T2FLAIRc (8.3 versus 5.8, P < .001) and T1c (4.1 versus 3.5, P = .02). The AUC for T2FLAIRc (0.83; 95% CI, 0.72-0.92) was greater than that for T1c (0.70; 95% CI, 0.56-0.83) (P = .04). The AUC of DSC-derived relative CBV (0.82; 95% CI, 0.70-0.93) was not significantly different from that of T2FLAIRc (P = .9).

Conclusions: A higher normalized T1c and T2FLAIRc signal intensity was found for RN. In a univariable test, the mean T2FLAIRc signal intensity of enhancing voxels showed good discrimination performance for distinguishing RN from TP. The results of this work demonstrate the potential of T2FLAIRc as an imaging biomarker in the work-up of RN in patients with brain metastases.

Background and purpose: Contrast-enhanced MRI (CEMRI) is a commonly used imaging technique for craniopharyngioma surveillance; however, it carries risks such as allergic reaction and gadolinium deposition. This study evaluates the efficacy of non contrast-enhanced MRI (NCMRI) with a balanced steady-state free precession (bSSFP) sequence compared with CEMRI T1-weighted imaging for craniopharyngioma surveillance.

Materials and methods: Twenty-nine patients with craniopharyngioma (16 females/13 males, mean age =21.5 ± 4.3 years) with CEMRIs, including a bSSFP sequence, were evaluated. For each patient, 2 blinded neuroradiologists compared the dimensions of residual craniopharyngioma on non-contrast- and contrast-enhanced sequences. Tumor volume and solid/cystic component measurements were evaluated by using paired t-tests. Diagnostic confidence levels for non-contrast- and contrast-enhanced evaluations were measured by using a 3-point scale (2 = confident, 1 = adequate, 0 = unsure). Analyses of tumor involvement of cranial nerves (CNs) and adjacent vasculature and diagnostic confidence were performed by using Fisher exact and chi-square tests.

Results: No significant difference was observed between residual tumor volumes in both studies (18.86 ± 21.67 cm³ versus 17.64 ± 23.85 cm³, P = .55) and measurements of dominant solid component volume, number of cystic components, and largest cystic component volume (2.71 ± 3.47 cm³ versus 3.95 ± 5.51 cm³, P = .10; 2.5 ± 1.5 versus 2.9 ± 1.5, P = .10; 7.61 ± 13.41 versus 6.84 ± 13.37 cm³, P = .22, respectively). Tumor involvement of CNs II (P = .64), III (P = .42), and adjacent vasculature (P = .05) showed no significant differences in detection. Diagnostic confidence was comparable in evaluating CN II, vascular structures, and third ventricle (P > .05) involvement. Higher levels of confidence were observed with bSSFP sequences for the detection of CN III involvement (P = .0001) and with contrast-enhanced T1-weighted imaging for cavernous sinus involvement (P = .02).

Conclusions: NCMRI techniques by using a bSSFP sequence provide similar characterization of craniopharyngiomas as contrast-enhanced techniques.

Background and purpose: Mechanical thrombectomy (MT) along with emergent carotid stent placement (eCAS) has been suggested to have a greater benefit in patients with tandem lesions (TL), compared with other strategies of treatment. Nonetheless, there is no agreement on whether the intracranial occlusion should be treated before the cervical ICA lesion, or vice versa. In this retrospective multicenter study, we sought to compare clinical and procedural outcomes of the 2 different treatment approaches in patients with TL.

Materials and methods: The prospective databases of 17 comprehensive stroke centers were screened for consecutive patients with TL who received MT and eCAS. Patients were divided in 2 groups based on whether they received MT before eCAS (MT-first approach) or eCAS before MT (eCAS-first approach). Propensity score matching was used to estimate the effect of the retrograde-versus-anterograde approach on procedure-related and clinical outcome measures. These included the modified TICI score 2b-3, other procedure-related parameters and adverse events after the endovascular procedure, and the ordinal distribution of the 90-day mRS scores.

Results: A total of 295 consecutive patients were initially enrolled. Among them, 208 (70%) received MT before eCAS. After propensity score matching, 56 pairs of patients were available for analysis. In the matched population, the MT-first approach resulted in a higher rate of successful intracranial recanalization (91% versus 73% in the eCAS-first approach, P = .025) and a mean shorter groin-to-reperfusion time (72 [SD, 38] minutes versus 93 [SD, 50] minutes in the anterograde approach, P = .017). Despite a higher rate of efficient recanalization in the MT-first group, we did not observe a significant difference regarding the ordinal distribution of the 90-day mRS scores. Rates of procedure-related adverse events and the occurrence of both parenchymal hemorrhage types 1 and 2 were comparable.

Conclusions: Our study demonstrates that in patients with TL undergoing endovascular treatment, prioritizing the intracranial occlusion is associated with an increased rate of efficient MT and faster recanalization time. However, this strategy does not have an advantage in long-term clinical outcome. Future controlled studies are needed to determine the optimal treatment technique.

Cortically based brain tumors in children constitute a unique set of tumors with variably aggressive biologic behavior. Because radiologists play an integral role on the multidisciplinary medical team, a clinically useful and easy-to-follow flow chart for the differential diagnoses of these complex brain tumors is essential. This proposed algorithm tree provides the latest insights into the typical imaging characteristics and epidemiologic data that differentiate the tumor entities, taking into perspective the 2021 World Health Organization's classification and highlighting classic as well as newly identified pathologic subtypes by using current molecular understanding.

Background and purpose: Cerebellar heterotopia (CH) is a neuroradiologic abnormality that is poorly reported and investigated in the literature. It can be observed as an isolated finding, but it has been mainly reported in the context of cerebellar dysgenesis and syndromic conditions. This study aims to provide a comprehensive neuroradiologic, clinical, and genetic characterization of a cohort of pediatric patients with CH.

Materials and methods: Patients with a diagnosis of CH were systematically selected from the neuroimaging databases of the 4 Italian centers participating in this retrospective study. For each patient, information regarding demographic, clinical, genetic, and neuroradiologic data was collected.

Results: Thirty-two pediatric patients were recruited and subdivided into 2 groups: patients with isolated CH and/or cerebellar malformations (n = 18) and patients with CH associated with cerebral malformations (n = 14). Isolated CH consistently showed a peripheral subcortical localization in the inferior portion of cerebellar hemispheres, with either unilateral or bilateral distribution. Ten patients belonging to the second group had a diagnosis of CHARGE syndrome, and their nodules of CH were mainly but not exclusively bilateral, symmetric, located in the peripheral subcortical zone and the inferior portion of the cerebellar hemispheres. The remaining 4 patients of the second group showed either bilateral or unilateral CH, located in both the peripheral cortex and deep white matter and the superior and inferior portions of cerebellum. Patients with isolated CH showed a high prevalence of language development delay; neurodevelopmental disorders were the most represented clinical diagnoses. Recurring features were behavioral problems and motor difficulties. A conclusive genetic diagnosis was found in 18/32 patients.

Conclusions: We found distinctive neuroradiologic patterns of CH. Genetic results raise the possibility of a correlation between cerebellar morphologic and functional developmental disruption, underscoring the importance of CH detection and reporting to orient the diagnostic path.

Transcranial focused ultrasound (FUS) is a versatile, MR-guided, incisionless intervention with diagnostic and therapeutic applications for neurologic and psychiatric diseases. It is currently FDA-approved as a thermoablative treatment of essential tremor and Parkinson disease. However, other applications of FUS including BBB opening for diagnostic and therapeutic applications, sonodynamic therapy, histotripsy, and low-intensity focused ultrasound neuromodulation are all in clinical trials. While FUS targeting for essential tremor and Parkinson disease has classically relied on an indirect, landmark-based approach, development of novel, advanced MR imaging techniques such as DTI tractography and fast gray matter acquisition T1 inversion recovery has the potential to improve individualized targeting and thus potentially enhance treatment response, decrease treatment times, and avoid adverse effects. As the technology advances and the number of clinical applications increases, the role of the neuroradiologist on a multidisciplinary team will be essential in pairing advanced structural and functional imaging to further this image-guided procedure via a precision medicine approach. This multi-institutional report, written by an experienced team of neuroradiologists, neurosurgeons, and neurologists, summarizes current practices, the use of advanced imaging techniques for transcranial MR-guided high-intensity FUS, recommendations for clinical implementation, and emerging clinical indications.