Insights Into MRI Neuroimaging Patterns of COVID-19 in Children: A Retrospective Comprehensive Analysis.

RATIONALE AND OBJECTIVES: Neurological complications associated with coronavirus disease (COVID-19) have been reported in children; however, data on neuroimaging findings remain limited. This study aimed to comprehensively examine neuroimaging patterns of COVID-19 in children and their relationship with clinical outcomes. MATERIALS AND METHODS: This retrospective cross-sectional study involved reviewing the medical records and MRI scans of 95 children who developed new neurological symptoms within 2-4 weeks of clinical and laboratory confirmation of COVID-19. Patients were categorized into four groups based on guidelines approved by the Centers for Disease Control and Prevention (CDC). Initial brain/spinal MRI was performed. Images were reviewed by three blinded radiologists, and the findings were analyzed and categorized based on the observed patterns in the brain and spinal cord. Follow-up MRI was performed and analyzed to track lesion progression. RESULTS: Encephalopathy was the most common neurological symptom (50.5%). The most common initial MRI involvement patterns were non-confluent multifocal hyperintense white matter (WM) lesions (36.8%) and ischemia (18.9%). Most patients who underwent follow-up MRI (n = 56) showed complete resolution (69.9%); however, some patients developed encephalomalacia and myelomalacia (23.2% and 7.1%, respectively). Non-confluent hyperintense WM lesions were associated with good outcomes (45.9%, P = 0.014), whereas ischemia and hemorrhage were associated with poor outcomes (44.1%, P < 0.001). CONCLUSION: This study revealed diverse neuroimaging patterns in pediatric COVID-19 patients. Non-confluent WM lesions were associated with good outcomes, whereas ischemia and hemorrhage were associated with poorer prognoses. Understanding these patterns is crucial for their early detection, accurate diagnosis, and appropriate management.

Pediatric posterior reversible encephalopathy syndrome: Can MR imaging features predict outcomes in non-oncologic patients?

PURPOSE: Identify MR features predictive of poor outcomes in non-oncologic pediatric PRES. METHOD: A six-year search of all non-oncologic pediatric patients with clinical and MR features of PRES was performed. Modified Rankin scores were used to classify clinical outcomes into good versus poor, then clinical and MR features were compared among groups. Univariate and multivariate analysis was performed to identify MR predictors of poor outcomes for various imaging features, and p-values < 0.05 were considered statistically significant. RESULTS: One hundred and forty-one patients (mean age 10.1 ± 3.0 years, male to female ratio 1:1.1) were included. Clinically, nephrotic syndrome (p = 0.03), focal deficits (p = 0.04), longer hospitalization (p < 0.001), and mechanical ventilation (p < 0.001) were significantly associated with poor outcomes. Univariate analysis revealed that deep grey matter nuclei (OR = 5.29, 95 % CI: 1.6-18.0) and cerebellar edema patterns (OR = 3.49, 95 % CI: 1.3-9.5), cytotoxic edema (OR = 63.6, 95 % CI:16.5-244.2), hemorrhage (OR = 16.58, 95 % CI: 4.3-64.2), and severe PRES patterns (OR = 11.0, 95 % CI: 3.5-34.7) on MR were all significantly associated with poor outcomes (p-values = 0.008 and 0.014, <0.001, <0.001, and < 0.001, respectively). This remained true for cytotoxic edema (OR = 84.26, 95 % CI: 17.3-410.9, p-value < 0.001) and hemorrhage (OR = 44.56, 95 % CI: 6.9-289.7, p-value < 0.001) on multivariate analysis. CONCLUSION: Diffusion restriction and hemorrhage on initial MR scans were the two independent predictors of poor outcomes in non-oncologic pediatric patients.

Spectral augmentation for heart chambers segmentation on conventional contrasted and unenhanced CT scans: an in-depth study.

PURPOSE: Recently, machine learning has outperformed established tools for automated segmentation in medical imaging. However, segmentation of cardiac chambers still proves challenging due to the variety of contrast agent injection protocols used in clinical practice, inducing disparities of contrast between cavities. Hence, training a generalist network requires large training datasets representative of these protocols. Furthermore, segmentation on unenhanced CT scans is further hindered by the challenge of obtaining ground truths from these images. Newly available spectral CT scanners allow innovative image reconstructions such as virtual non-contrast (VNC) imaging, mimicking non-contrasted conventional CT studies from a contrasted scan. Recent publications have demonstrated that networks can be trained using VNC to segment contrasted and unenhanced conventional CT scans to reduce annotated data requirements and the need for annotations on unenhanced scans. We propose an extensive evaluation of this statement. METHOD: We undertake multiple trainings of a 3D multi-label heart segmentation network with (HU-VNC) and without (HUonly) VNC as augmentation, using decreasing training dataset sizes (114, 76, 57, 38, 29, 19 patients). At each step, both networks are tested on a multi-vendor, multi-centric dataset of 122 patients, including different protocols: pulmonary embolism (PE), chest-abdomen-pelvis (CAP), heart CT angiography (CTA) and true non-contrast scans (TNC). An in-depth comparison of resulting Dice coefficients and distance metrics is performed for the networks trained on the largest dataset. RESULTS: HU-VNC-trained on 57 patients significantly outperforms HUonly trained on 114 regarding CAP and TNC scans (mean Dice coefficients of 0.881/0.835 and 0.882/0.416, respectively). When trained on the largest dataset, significant improvements in all labels are noted for TNC and CAP scans (mean Dice coefficient of 0.882/0.416 and 0.891/0.835, respectively). CONCLUSION: Adding VNC images as training augmentation allows the network to perform on unenhanced scans and improves segmentations on other imaging protocols, while using a reduced training dataset.

In Vivo Molecular K-Edge Imaging of Atherosclerotic Plaque Using Photon-counting CT.

Background Macrophage burden is a major factor in the risk of atherosclerotic plaque rupture, and its evaluation remains challenging with molecular noninvasive imaging approaches. Photon-counting CT (PCCT) with k-edge imaging aims to allow for the specific detection of macrophages using gold nanoparticles. Purpose To perform k-edge imaging in combination with gold nanoparticles to detect and quantify the macrophage burden within the atherosclerotic aortas of rabbits. Materials and Methods Atherosclerotic and control New Zealand white rabbits were imaged before and at several time points up to 2 days after intravenous injection of gold nanoparticles (3.5 mL/kg, 65 mg gold per milliliter). Aortic CT angiography was performed at the end of the follow-up using an intravenous injection of an iodinated contrast material. Gold k-edge and conventional CT images were reconstructed for qualitative and quantitative assessment of the macrophage burden. PCCT imaging results were compared with findings at histologic examination, quantitative histomorphometry, transmission electron microscopy, and quantitative inductively coupled plasma optical emission spectrometry. Pearson correlations between the macrophage area measured in immunostained sections and the concentration of gold and attenuation measured in the corresponding PCCT sections were calculated. Results Seven rabbits with atherosclerosis and four control rabbits without atherosclerosis were analyzed. In atherosclerotic rabbits, calcifications were observed along the aortic wall before injection. At 2 days after injection of gold nanoparticles, only gold k-edge images allowed for the distinction of plaque enhancement within calcifications and for lumen enhancement during angiography. A good correlation was observed between the gold concentration measured within the wall and the macrophage area in 35 plaques (five per rabbit) (r = 0.82; 95% CI: 0.67, 0.91; P < .001), which was higher than that observed on conventional CT images (r = 0.41; 95% CI: 0.09, 0.65; P = .01). Transmission electron microscopy and inductively coupled plasma optical emission spectrometry analyses confirmed the gold k-edge imaging findings. Conclusion Photon-counting CT with gold nanoparticles allowed for the noninvasive evaluation of both molecular and anatomic information in vivo in rabbits with atherosclerotic plaques. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Leiner in this issue.

Quantifying differences in femoral head and neck asphericity in CAM type femoroacetabular impingement and hip dysplasia versus controls using radial 3DCT imaging and volumetric segmentation.

OBJECTIVE: Femoroacetabular impingement (FAI) and hip dysplasia are the most common causes of groin pain originating from the hip joint. To date, there is controversy over cut-off values for the evaluation of abnormal femoral head-neck anatomy with significant overlap between the normal and abnormal hips. Our aim was to perform three-dimensional CT analysis of femoral head and bump anatomy to quantify common hip pathologies (FAI and hip dysplasia) vs controls. METHODS: Consecutive patients who underwent three-dimensional CT imaging for hip dysplasia or CAM type FAI were compared to asymptomatic controls. α angles on radial CT and 3D volumetric femoral head and bump segmentations were performed by two readers. Inter- and intrapatient comparisons were performed including interreader and receiver operating characteristic analyses. RESULTS: 25 FAI patients, 16 hip dysplasia patients and 38 controls were included. FAI and dysplasia patients exhibited higher α angles and higher bump-head volume ratios than the controls (p < 0.05). Larger bump volumes were found among FAI than dysplasia patients and contralateral hips of FAI patients were also different than the controls. α angle at 2 o'clock and bump to head ratio showed the highest area under the curve for patients vs controls. The interreader reliability was better for volumetric segmentation (intraclass correlation coefficient = 0.35-0.84) as compared to the α angles (intraclass correlation coefficient = 0.11-0.44). CONCLUSION: Patients with FAI and dysplasia exhibit different femoral head anatomy than asymptomatic controls. Volumetric segmentation of femoral head and bump is more reliable and better demonstrates the bilateral femoral head anatomy differences in hip patients vs controls. ADVANCES IN KNOWLEDGE: Utilizing information from 3D volumetric bump assessment in patients with FAI and dysplasia, the physicians may be able to more objectively and reliably evaluate the altered anatomy for better pre-surgical evaluation.

Regional muscle changes in adult dysfunctional hip conditions of femoroacetabular impingement and hip dysplasia.

OBJECTIVE: To analyze regional muscle CT density and bulk in femoroacetabular impingement (FAI) and hip dysplasia (HD) versus controls. MATERIALS AND METHODS: Patients who obtained perioperative CT imaging for FAI and HD before surgery were retrospectively studied. Asymptomatic controls included for comparison. Two readers independently evaluated regional hip muscle [iliopsoas (IP), rectus femoris (RF), gluteus minimus (Gm), and medius (GM)] density, muscle area, and muscle circumference. Inter-observer reliability calculated using intra-class correlation coefficient (ICC). RESULTS: A consecutive series of 25 FAI patients, 16 HD patients, and 38 controls were recruited in the study. FAI patients had significantly greater Gm and GM circumferences as well as greater RF and IP areas on the normal side compared to the asymptomatic control group (p values 0.004, 0.032, 0.033, and 0.028, respectively). In addition, Gm and RF circumferences and RF area were significantly larger (p values 0.029, 0.036, and 0.014, respectively) in FAI patients on the affected side compared to the control group. HD patients had significantly smaller Gm and GM circumferences on the affected side than normal side measurements in FAI group (p values 0.043 and 0.003, respectively). Normal side GM circumference was also smaller in HD patients than normal side FAI hips (p value 0.02). There was no significant difference between the measurements on normal and abnormal sides in each disease group. No significant difference was found between measurements of HD compared to controls (p > 0.05). No muscle density differences were seen among different groups. There was moderate to excellent inter-reader reliability for all measurements except Gm muscle density. CONCLUSIONS: Muscle analysis was able to quantify differences among patients with FAI, HD, and asymptomatic controls. These changes could indicate either a muscle imbalance contributing to the pathology or disuse atrophy, which may have implications for specific muscle-strengthening therapies and rehabilitation procedures in such patients.

Management of uterine adenomyosis: current trends and uterine artery embolization as a potential alternative to hysterectomy.

Adenomyosis is a challenging clinical condition that is commonly being diagnosed in women of reproductive age. To date, many aspects of the disease have not been fully understood, making management increasingly difficult. Over time, minimally invasive diagnostic and treatment methods have developed as more women desire uterine preservation for future fertility or to avoid major surgery. Several uterine-sparing treatment options are now available, including medication, hysteroscopic resection or ablation, conservative surgical methods, and high-intensity focused ultrasound each with its own risks and benefits. Uterine artery embolization is an established treatment option for uterine fibroids and has recently gained ground as a safe and cost-effective method for treatment of uterine adenomyosis with promising results. In this review, we discuss current trends in the management of uterine adenomyosis with a special focus on uterine artery embolization as an alternative to hysterectomy.

Cam-type femoroacetabular impingement-correlations between alpha angle versus volumetric measurements and surgical findings.

AIM: Determine correlations of 3DCT cam-type femoroacetabular impingement (FAI) measurements with surgical findings of labral tear and cartilage loss. METHODS: Digital search of symptomatic cam-type FAI from July 2013 to August 2016 yielded 43 patients. Two readers calculated volumes of femoral head, bump, and alpha angles on 3DCT images. Correlations between CT and surgical findings, inter-, and intra-reader reliabilities were assessed using Spearman rank correlation and intraclass correlation coefficients (ICC). RESULTS: Thirteen men and 14 women aged 37 ± 10 (mean ± SD) years were included. Most common clinical finding was positive flexion-adduction-internal rotation (70.4%). Twenty-seven labral tears and 20 cartilage defects were surgically detected. Significant correlations existed between femoral bump, head volumes, and extent of the labral tear (p = 0.008 and 0.003). No significant correlations were found between the alpha angles at 12 to 3 o'clock and the extent of labral tear (p = 0.2, 0.8, 0.9, and 0.09) or any measurement with the cartilage loss (p values for alpha 12 to 3, bump, and head volumes = 0.7, 0.3, 0.9, 0.9, 0.07, and 0.2). Inter- and intra-reader reliabilities were excellent to moderate for femoral head and bump volumes (ICC = 0.85, 0.52, and 0.8, 0.5) and moderate to poor for alpha angles (ICC = 0.48, 0.40, 0.05, 0.25 and 0.3, 0.24, 0.29, 0.49). CONCLUSION: Three dimensional volumetric measurements of cam-type FAI significantly correlate with the extent of intraoperative labral tears. Superior inter- and intra-reader reliability to that of alpha angles renders it a more clinically relevant measurement for quantifying cam morphology. KEY POINTS: • The 3DCT bump volume and femoral head volume showed significant correlations with the extent of labral tear (p values = 0.008 and 0.003). • No significant correlations were seen between alpha angles and the extent of labral tear (p values > 0.05). • Inter- and intra-reader reliability was excellent to moderate (ICC = 0.85 and 0.52, 0.8, and 0.5) for femoral head and bump volumes while inter- and intra-reader reliability was fair to poor (ICC = 0.48, 0.40, 0.05, 0.25 and 0.3, 0.24, 0.29, 0.49) for alpha angles.

Magnetic Resonance Neurography of the Lumbosacral Plexus in Failed Back Surgery Syndrome.

STUDY DESIGN: Retrospective clinical case series. OBJECTIVE: To study the role of magnetic resonance neurography (MRN) of the lumbosacral plexus in management of patients with failed back surgery syndrome (FBSS). SUMMARY OF BACKGROUND DATA: FBSS is one of the major problems in health care, affecting up to 40% of patients after spine surgery. To date, no imaging modality has been used to effectively classify nerve compression, because nerve injuries are challenging to detect on conventional lumbar spine magnetic resonance imaging (MRI). To our knowledge, no previous studies have addressed the use of MRN in FBSS or compared it to lumbar spine MRI. METHODS: From 203 consecutive 3 T MRN studies of lumbosacral plexus in 1 year, 12% (25/203) presented as FBSS. Demographic data, number of previous lumbar MRIs and their findings, MRN findings, interval between MRI and MRN, pre-and post-MRN diagnosis, pain levels, and treatments were recorded. Changes in diagnosis, treatment, and outcomes after MRN were determined. RESULTS: The final sample of 25 patients had a mean age 62 ±â€Š15 and male to female ratio 1:1.08. Approximately 88% (22/25) had previous lumbar MRI, of which 27% had 3 or more. Most common imaging findings were neuroforaminal stenosis 22.6% (7/31) on MRI and neuropathy 22.9% (19/83) on MRN. Mean interval between MRI and MRN was 13.9 ±â€Š28.3 months. Lumbar MRIs were inconclusive in 36% (8/22). MRN detected 63% (52/83) more findings and changed the diagnosis and treatment in 12% and 48% of FBSS cases, respectively. Favorable outcomes were recorded in 40% to 67% of patients following MRN-guided treatments. CONCLUSION: FBSS is a complex problem and MRN of lumbosacral plexus impacts its management by better directing source of symptoms. LEVEL OF EVIDENCE: 4.

Series of rare lung diseases mimicking imaging patterns of common diffuse parenchymal lung diseases.

Diffuse parenchymal lung diseases (DPLDs) encompass a variety of restrictive and obstructive lung pathologies. In this article, the authors discuss a series of rare pulmonary entities and their high-resolution computed tomography imaging appearances, which can mimic more commonly encountered patterns of DPLDs. These cases highlight the importance of surgical lung biopsies in patients with imaging findings that do not show typical imaging features of usual interstitial pneumonia.

Magnetic Resonance Neurography in Chronic Lumbosacral and Pelvic Pain: Diagnostic and Management Impact-Institutional Audit.

BACKGROUND/OBJECTIVE: Low back and pelvic pain are among the most prevalent conditions worldwide, with major social and economic costs. The aim of this study was to evaluate the role of magnetic resonance neurography (MRN) of lumbosacral plexus in the management and outcomes of these patients with chronic pain. METHODS: Consecutive patients with chronic lumbosacral and pelvic pain referred for MRN over a year were included. Preimaging and postimaging clinical diagnosis and treatment, pain levels, and location were recorded. Pain-free survival was compared between treatments using a Cox proportional hazards model. RESULTS: A total of 202 patients with mean age 53.7 ± 14.8 years and a male/female ratio of 1:1.53 were included. Of these patients, 115 presented with radiculopathy (57%), 56 with pelvic pain (28%), and 31 with groin pain (15%). Mean initial pain level was 6.9 ± 1.9. Mean symptom duration was 4.21 ± 5.86 years. Of these patients, 143 (71%) had a change in management because of MRN. After MRN, reduction in pain levels was observed in 21 of 32 patients receiving conservative treatment (66%), 42 of 67 receiving injections (63%), and 27 of 33 receiving surgery (82%). Follow-ups were available in 131 patients. Median pain-free survival was 12 months. Patients treated with surgery had significantly lower pain recurrence than patients receiving other treatments in the same time frame (hazard ratio, 3.6; 95% confidence interval, 1.4-9.2; P = 0.0061). CONCLUSIONS: MRN use in chronic lumbosacral and pelvic pain led to a meaningful change in diagnosis and treatment. After MRN, conservative treatment and injections provided pain relief; however, patients benefited more from surgery than from any other treatment.

Hallux Valgus Evaluation on MRI: Can Measurements Validated on Radiographs Be Used?

Hallux valgus (HV) is a common deformity of the great toe affecting >23% of adults in the United States. The severity of the deformity is traditionally analyzed using radiographs to determine measurements such as the HV and intermetatarsal angles. We sought to determine the relationship between the radiographic and magnetic resonance imaging (MRI) measurements because this is not yet known. Two of us analyzed a series of 56 consecutive patients who had had radiographs and MRI performed on the same foot between April 27, 2015 and March 9, 2016 and who satisfied all other inclusion and exclusion criteria (age 18 to 100 years, no history of recent foot trauma, and no metal hardware in the foot). We found excellent interreader reliability (intraclass correlation 0.89 to 0.96) and intermodality agreement (intraclass correlation 0.83 to 0.91). The HV angle measured 15.0° ± 8.8° on the MRI scans and 13.8° ± 8.7° on the radiographs (mean difference -1.15° ± 3.89°), and the intermetatarsal angle was 9.0° ± 3.1° on the MRI scans and 8.8° ± 2.9° on the radiographs (mean difference -0.22° ± 2.10°). The HV measurements were reliable on both radiographs and MRI for the range of values tested. Small intermodality statistically significant differences in HV angle measurements were found; however, these might not be enough to be clinically significant.

Magnetic Resonance Neurography of Traumatic and Nontraumatic Peripheral Trigeminal Neuropathies.

PURPOSE: The clinical neurosensory testing (NST) is currently the reference standard for the diagnosis of traumatic and nontraumatic peripheral trigeminal neuropathies (PTNs), but exhibits both false-positive and false-negative results compared with surgical findings and frequently results in treatment decision delays. We tested the hypothesis that magnetic resonance neurography (MRN) of PTNs can serve as a diagnostic modality by correlating the NST, MRN, and surgical findings. MATERIALS AND METHODS: Sixty patients with traumatic and nontraumatic PTN of varying etiologies and Sunderland classifications underwent NST, followed by MRN using 1.5T and 3.0T scanners. The protocol included 2-dimensional and 3-dimensional (3D) imaging, including diffusion imaging and isotropic 3D PSIF. The MRN findings were read by 2 readers in consensus with the clinical findings but without knowing the side of abnormality. The MRN results were summarized using the Sunderland classification. In 26 patients, surgery was performed, and the Sunderland classification was assigned using the surgical photographs. Agreement between the MRN findings and NST/surgical classification was evaluated using kappa statistics. Pearson's correlation coefficient was used to assess the correlation between continuous measurements of MRN/NST and surgical classification. RESULTS: Of the 60 patients, 19 males and 41 females, mean age 41 years (range 12 to 75), with 54 complaints of altered sensation of the lip, chin, or tongue, including 16 with neuropathic pain and 4 with no neurosensory complaint, were included. Third molar surgery (n = 29) represented the most common cause of traumatic PTN. Assuming 1 nerve abnormality per patient, the lower class was accepted, a kappa of 0.57 was observed between the MRN and NST classification. A kappa of 0.5 was found between MRN and surgical findings with a Pearson correlation coefficient of 0.67. CONCLUSIONS: MRN anatomically maps PTNs and stratifies the nerve injury and neuropathies with moderate to good agreement with NST and surgical findings for clinical use.

Clinical Value of Multiparametric Whole-Body Magnetic Resonance Imaging over Whole-Spine Magnetic Resonance Imaging in Patients with Neurofibromatosis Type I.

OBJECTIVE: To determine the clinical value of multiparametric whole-body (WBMRI) over whole-spine magnetic resonance imaging (WSMRI) in patients with neurofibromatosis type 1 (NF1). METHODS: A consecutive series of 30 patients with known NF1 underwent WBMRI screening using anatomic, diffusion, and contrast imaging over a 30-month period. Thirteen of 30 patients also had WSMRI. Tumors were classified per location and morphology and were software segmented to determine numbers and volumes. Extra tumor burden detected by WBMRI was assessed. The comparison was made between WBMRI and WSMRI in 13 patients who had both types of scans. Enhancement characteristics were noted and 2 readers recorded apparent diffusion coefficient (ADC) in 30 patients with WBMRI scans. Interobserver performance was assessed using intraclass correlations. A 2-sample test was used for testing mean differences between tumors. RESULTS: The age of 30 patients with WBMRI and 13 patients with WSMRI were 39.4 ± 14.4 and 41.54 ± 10.79 years (mean ± standard deviation) and male/female ratio was 1:1.73 and 1:2.25, respectively. Only 1 patient was found to have a heterogeneously enhancing lumbar paraspinal malignant peripheral nerve sheath tumor, seen on both WBMRI and WSMRI. The additional total number of tumors on WBMRI was 2766 and 2602 tumors were missed on WSMRI. The volume of tumors was 16,053 cm3 and 15,614 cm3 of tumor burden was incrementally detected on WBMRI. Mean ADC of superficial tumors was significantly lower than that of deep tumors (1.93 ± 0.39 × 10-3 mm2/second and 2.26 ± 0.56 × 10-3 mm2/second, respectively; P = 0.009), whereas no ADC differences were seen in plexiform versus discrete tumors (P = 0.64). Interobserver performance for ADC was excellent (intraclass correlation, 0.84). CONCLUSIONS: Multiparametric WBMRI provides superior determination of tumor burden and should be considered as a preferred method for evaluation of patients with NF1.