American Journal of Neuroradiology最新文献

Background and purpose: Neonatal hypocalcemia is the most common metabolic disorder, and whether asymptomatic disease should be treated with calcium supplements remains controversial. We aimed to quantify neonatal hypocalcemia's global CBF and cerebral metabolic rate of oxygen (CMRO₂) using physiologic MR imaging and elucidate the pathophysiologic vulnerabilities of neonatal hypocalcemia.

Materials and methods: A total of 37 consecutive patients with neonatal hypocalcemia were enrolled. They were further divided into subgroups with and without structural MR imaging abnormalities, denoted as neonatal hypocalcemia-a (n = 24) and neonatal hypocalcemia-n (n = 13). Nineteen healthy neonates were enrolled as a control group. Brain physiologic parameters determined using phase-contrast MR imaging, T2-relaxation-under-spin-tagging MR imaging, and brain volume were compared between patients with neonatal hypocalcemia (their subgroups) and controls. Predictors for neonatal hypocalcemia-related brain injuries were identified using multivariate logistic regression analysis and expressed as ORs with 95% CIs.

Results: Patients with neonatal hypocalcemia showed significantly lower CBF and CMRO₂ compared with controls. Furthermore, the neonatal hypocalcemia-a subset (versus controls or neonatal hypocalcemia-n) had significantly lower CBF and CMRO₂. There was no obvious difference in CBF and CMRO₂ between the neonatal hypocalcemia-n subset and controls. CBF and CMRO₂ were independently associated with neonatal hypocalcemia. The ORs were 0.80 (95% CI, 0.65-0.99) and 0.97 (95% CI, 0.89-1.05) for CBF and CMRO₂, respectively.

Conclusions: Neonatal hypocalcemia with structural damage may exhibit lower hemodynamics and cerebral metabolism. CBF may be useful in assessing the need for calcium supplementation in asymptomatic neonatal hypocalcemia to prevent brain injury.

Benign and malignant pediatric orbital lesions can sometimes have overlapping features on conventional MR imaging sequences. MR imaging of 27 children was retrospectively reviewed to describe the signal of some common pediatric extraocular orbital lesions on arterial spin-labeling and to evaluate whether this sequence helps to discriminate malignant from benign masses, with or without ADC value measurements. Qualitative and quantitative assessments of arterial spin-labeling CBF and ADC were performed. All lesions were classified into 3 arterial spin-labeling perfusion patterns: homogeneous hypoperfusion (pattern 1, n = 15; benign lesions), heterogeneous hyperperfusion (pattern 2, n = 9; cellulitis, histiocytosis, malignant tumors), and homogeneous intense hyperperfusion (pattern 3, n = 3; infantile hemangiomas). Arterial spin-labeling can be a valuable tool to improve the diagnostic confidence of some orbital lesions, including infantile hemangioma. An algorithm is proposed.

Background and purpose: Accurate segmentation of brain metastases is important for treatment planning and evaluating response. The aim of this study was to assess the performance of a semiautomated algorithm for brain metastases segmentation using Background Layer Statistics (BLAST).

Materials and methods: Nineteen patients with 48 parenchymal and dural brain metastases were included. Segmentation was performed by 4 neuroradiologists and 1 radiation oncologist. K-means clustering was used to identify normal gray and white matter (background layer) in a 2D parameter space of signal intensities from postcontrast T2 FLAIR and T1 MPRAGE sequences. The background layer was subtracted and operator-defined thresholds were applied in parameter space to segment brain metastases. The remaining voxels were back-projected to visualize segmentations in image space and evaluated by the operators. Segmentation performance was measured by calculating the Dice-Sørensen coefficient and Hausdorff distance using ground truth segmentations made by the investigators. Contours derived from the segmentations were evaluated for clinical acceptance using a 5-point Likert scale.

Results: The median Dice-Sørensen coefficient was 0.82 for all brain metastases and 0.9 for brain metastases of ≥10 mm. The median Hausdorff distance was 1.4 mm. Excellent interreader agreement for brain metastases volumes was found with an intraclass correlation coefficient = 0.9978. The median segmentation time was 2.8 minutes/metastasis. Forty-five contours (94%) had a Likert score of 4 or 5, indicating that the contours were acceptable for treatment, requiring no changes or minor edits.

Conclusions: We show accurate and reproducible segmentation of brain metastases using BLAST and demonstrate its potential as a tool for radiation planning and evaluating treatment response.

Background and purpose: Chondrosarcoma and synovial chondromatosis of the temporomandibular joint share overlapping clinical and histopathologic features. We aimed to identify CT and MR imaging features to differentiate chondrosarcoma from synovial chondromatosis of the temporomandibular joint.

Materials and methods: The CT and MR images of 12 and 35 patients with histopathologically confirmed chondrosarcoma and synovial chondromatosis of the temporomandibular joint, respectively, were retrospectively reviewed. Imaging features including lesion size, center, enhancement, destruction/sclerosis of surrounding bone, infiltration into the tendon of the lateral pterygoid muscle, calcification, periosteal reaction, and osteophyte formation were assessed. A comparison between chondrosarcoma and synovial chondromatosis was performed with a Student t test for quantitative variables and the Fisher exact test or linear-by-linear association test for qualitative variables. Receiver operating characteristic analysis was performed to determine the diagnostic performance for differentiation of chondrosarcoma and synovial chondromatosis based on a composite score obtained by assigning 1 point for each of 9 imaging features.

Results: High-risk imaging features for chondrosarcoma were the following: lesion centered on the mandibular condyle, destruction of the mandibular condyle, no destruction/sclerosis of the articular eminence/glenoid fossa, infiltration into the tendon of the lateral pterygoid muscle, absent or stippled calcification, periosteal reaction, internal enhancement, and size of ≥30.5 mm. The best cutoff value to discriminate chondrosarcoma from synovial chondromatosis was the presence of any 4 of these high-risk imaging features, with an area under the curve of 0.986 and an accuracy of 95.8%.

Conclusions: CT and MR imaging features can distinguish chondrosarcoma from synovial chondromatosis of the temporomandibular joint with improved diagnostic performance when a subcombination of 9 imaging features is used.

Background and purpose: The frequency and utility of gadolinium in evaluation of acute pediatric seizure presentation is not well known. The purpose of this study was to assess the utility of gadolinium-based contrast agents in MR imaging performed for the evaluation of acute pediatric seizure presentation.

Materials and methods: We identified consecutive pediatric patients with new-onset seizures from October 1, 2016, to September 30, 2021, who presented to the emergency department and/or were admitted to the inpatient unit and had an MR imaging of the brain for the evaluation of seizures. The clinical and imaging data were recorded, including the patient's age and sex, the use of IV gadolinium, and the underlying cause of epilepsy when available.

Results: A total of 1884 patients were identified for inclusion. Five hundred twenty-four (28%) patients had potential epileptogenic findings on brain MR imaging, while 1153 (61%) patients had studies with normal findings and 207 (11%) patients had nonspecific signal changes. Epileptogenic findings were subclassified as the following: neurodevelopmental lesions, 142 (27%); intracranial hemorrhage (traumatic or germinal matrix), 89 (17%); ischemic/hypoxic, 62 (12%); hippocampal sclerosis, 44 (8%); neoplastic, 38 (7%); immune/infectious, 20 (4%); phakomatoses, 19 (4%); vascular anomalies, 17 (3%); metabolic, 3 (<1%); and other, 90 (17%). Eight hundred seventy-four (46%) patients received IV gadolinium. Of those, only 48 (5%) cases were retrospectively deemed to have necessitated the use of IV gadolinium: Fifteen of 48 (31%) cases were subclassified as immune/infectious, while 33 (69%) were neoplastic. Of the 1010 patients with an initial noncontrast study, 15 (1.5%) required repeat MR imaging with IV contrast to further evaluate the findings.

Conclusions: Gadolinium contrast is of limited additive benefit in the imaging of patients with an acute onset of pediatric seizures in most instances.

Background and purpose: The time course of changes in posterior fossa morphology, quality of life, and neurologic function of patients with Chiari I malformation after craniocervical decompression requires further elaboration. To better understand the pace of these changes, we longitudinally studied patients with Chiari I malformation, with or without syringomyelia, before and after the operation for up to 5 years.

Materials and methods: Thirty-eight symptomatic adult patients (35 women, 3 men) diagnosed with Chiari I malformation only (n = 15) or Chiari I malformation and syringomyelia (n = 23) and without previous Chiari I malformation surgery were enrolled in a clinical study. Patients underwent outpatient study visits and MR imaging at 7 time points (ie, initial [before the operation], 3 months, 1 year, 2 years, 3 years, 4 years, and 5 years) during 5 years. The surgical procedure for all patients was suboccipital craniectomy, C1 laminectomy, and autologous duraplasty.

Results: Morphometric measurements demonstrated an enlargement of the CSF areas posterior to the cerebellar tonsils after the operation, which remained largely stable through the following years. There was a decrease in pain and improved quality of life after the operation, which remained steady during the following years. Reduction in pain and improved quality of life correlated with CSF area morphometrics.

Conclusions: Most changes in MR imaging morphometrics and quality of life measures occurred within the first year after the operation. A 1-year follow-up period after Chiari I malformation surgery is usually sufficient for evaluating surgical efficacy and postoperative MR imaging changes.

Background and purpose: White matter lesions are commonly found in patients with Fabry disease. Existing studies have shown elevated diffusivity in healthy-appearing brain regions that are commonly associated with white matter lesions, suggesting that DWI could help detect white matter lesions at an earlier stage This study explores whether diffusivity changes precede white matter lesion formation in a cohort of patients with Fabry disease undergoing yearly MR imaging examinations during a 5-year period.

Materials and methods: T1-weighted anatomic, FLAIR, and DWI scans of 48 patients with Fabry disease (23 women; median age, 44 years; range, 15-69 years) were retrospectively included. White matter lesions and tissue probability maps were segmented and, together with ADC maps, were transformed into standard space. ADC values were determined within lesions before and after detection on FLAIR images and compared with normal-appearing white matter ADC. By means of linear mixed-effects modeling, changes in ADC and ΔADC (relative to normal-appearing white matter) across time were investigated.

Results: ADC was significantly higher within white matter lesions compared with normal-appearing white matter (P < .01), even before detection on FLAIR images. ADC and ΔADC were significantly affected by sex, showing higher values in men (60.1 [95% CI, 23.8-96.3] ×10^-6mm²/s and 35.1 [95% CI, 6.0-64.2] ×10^-6mm²/s), respectively. ΔADC increased faster in men compared with women (0.99 [95% CI, 0.27-1.71] ×10^-6mm²/s/month). ΔADC increased with time even when only considering data from before detection (0.57 [95% CI, 0.01-1.14] ×10^-6mm²/s/month).

Conclusions: Our results indicate that in Fabry disease, changes in diffusion precede the formation of white matter lesions and that microstructural changes progress faster in men compared with women. These findings suggest that DWI may be of predictive value for white matter lesion formation in Fabry disease.

Background and purpose: Brain atrophy is an important surrogate for brain reserve, the capacity of the brain to cope with acquired injuries such as acute stroke. It is unclear how well atrophy measurements on MR imaging can be reproduced using NCCT imaging. We aimed to compare pragmatic atrophy measures on NCCT with MR imaging in patients with acute ischemic stroke.

Materials and methods: This is a post hoc analysis, including baseline NCCT and 24-hour follow-up MR imaging data from the Safety and Efficacy of Nerinetide (NA-1) in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial. Cortical atrophy was measured using the global cortical atrophy scale, and subcortical atrophy was measured using the intercaudate distance-to-inner-table width (CC/IT) ratio. Agreement and correlation between these measures on NCCT and MR imaging were calculated using the Gwet agreement coefficient 1 and Pearson correlation coefficients, respectively.

Results: Among 1105 participants in the ESCAPE-NA1 trial, interpretable NCCT and 24-hour MR imaging were available in 558 (50.5%) patients (mean age, 67.2 [SD, 13.7] years; 282 women). Cortical atrophy assessments performed on NCCT underestimated atrophy severity compared with MR imaging (eg, patients with global cortical atrophy of ≥1 assessed on NCCT = 133/558 [23.8%] and on MR imaging = 247/558 [44.3%]; a 20.5% difference). Overall, cortical (ie, global cortical atrophy) atrophy assessments on NCCT had substantial or better agreement with MR imaging (Gwet agreement coefficient 1 of > 0.784; P < .001). Subcortical atrophy measures (CC/IT ratio) showed strong correlations between NCCT and MR imaging (Pearson correlation = 0.746, P < .001).

Conclusions: Brain atrophy can be evaluated using simple measures in emergently acquired NCCT. Subcortical atrophy assessments on NCCT show strong correlations with MR imaging. Although cortical atrophy assessments on NCCT are strongly correlated with MR imaging ratings, there is a general underestimation of atrophy severity on NCCT.

Background and purpose: An MRI of the fetus can enhance the identification of perinatal developmental disorders, which improves the accuracy of ultrasound. Manual MRI measurements require training, time, and intra-variability concerns. Pediatric neuroradiologists are also in short supply. Our purpose was developing a deep learning model and pipeline for automatically identifying anatomic landmarks on the pons and vermis in fetal brain MR imaging and suggesting suitable images for measuring the pons and vermis.

Materials and methods: We retrospectively used 55 pregnant patients who underwent fetal brain MR imaging with a HASTE protocol. Pediatric neuroradiologists selected them for landmark annotation on sagittal single-shot T2-weighted images, and the clinically reliable method was used as the criterion standard for the measurement of the pons and vermis. A U-Net-based deep learning model was developed to automatically identify fetal brain anatomic landmarks, including the 2 anterior-posterior landmarks of the pons and 2 anterior-posterior and 2 superior-inferior landmarks of the vermis. Four-fold cross-validation was performed to test the accuracy of the model using randomly divided and sorted gestational age-divided data sets. A confidence score of model prediction was generated for each testing case.

Results: Overall, 85% of the testing results showed a ≥90% confidence, with a mean error of <2.22 mm, providing overall better estimation results with fewer errors and higher confidence scores. The anterior and posterior pons and anterior vermis showed better estimation (which means fewer errors in landmark localization) and accuracy and a higher confidence level than other landmarks. We also developed a graphic user interface for clinical use.

Conclusions: This deep learning-facilitated pipeline practically shortens the time spent on selecting good-quality fetal brain images and performing anatomic measurements for radiologists.