Evaluation of 3-dimensional stereotactic surface projection rendering of arterial spin labeling data in a clinical cohort.

BACKGROUND AND PURPOSE: To assess the feasibility of 3-dimensional stereotactic surface projection (3D-SSP) as applied to arterial spin labeling (ASL) in a clinical pilot study. METHODS: A retrospective sample of 10 consecutive patients who underwent ASL as part of a clinically indicated MR examination was collected during this pilot study. Five additional subjects with normal cerebral perfusion served as a control group. Following voxel-wise M0-correction, cerebral blood flow (CBF) quantification, and stereotactic anatomic standardization, voxel-wise CBF from an individual's ASL dataset was extracted to a set of predefined surface pixels (3D-SSP). A normal database was created from averaging the extracted CBF datasets of the control group. Patients' datasets were compared individually with the normal database by calculating a Z-score on a pixel-by-pixel basis and were displayed in 3D-SSP views for visual inspection. Independent, two-expert reader assessment, using a 3-point scale, compared standard quantitative CBF images to the 3D-SSP maps. RESULTS: Patterns and severities of regionally reduced CBF were identified, by both independent readers, in the 3D-SSP maps. Reader assessment demonstrated preference for 3D-SSP over traditionally displayed standard quantitative CBF images in three of four evaluated imaging metrics (p = .026, .031, and .013, respectively); 3D-SSP maps were never found to be inferior to the standard quantitative CBF images. CONCLUSIONS: Three-dimensional SSP maps are feasible in a clinical population and enable quantitative data extraction and localization of perfusion abnormalities by means of stereotactic coordinates in a condensed display. The proposed method is a promising approach for interpreting cerebrovascular pathophysiology.

Changes to pediatric brain tumors in 2021 World Health Organization classification of tumors of the central nervous system.

New tumor types are continuously being described with advances in molecular testing and genomic analysis resulting in better prognostics, new targeted therapy options and improved patient outcomes. As a result of these advances, pathological classification of tumors is periodically updated with new editions of the World Health Organization (WHO) Classification of Tumors books. In 2021, WHO Classification of Tumors of the Central Nervous System, 5th edition (CNS5), was published with major changes in pediatric brain tumors officially recognized including pediatric gliomas being separated from adult gliomas, ependymomas being categorized based on anatomical compartment and many new tumor types, most of them seen in children. Additional general changes, such as tumor grading now being done within tumor types rather than across entities and changes in definition of glioblastoma, are also relevant to pediatric neuro-oncology practice. The purpose of this manuscript is to highlight the major changes in pediatric brain tumors in CNS5 most relevant to radiologists. Additionally, brief descriptions of newly recognized entities will be presented with a focus on imaging findings.

Is a Close Follow-Up Computed Tomography Necessary for Acute Falcine and Tentorial Subdural Hematoma?

OBJECTIVE: This study aimed to assess the changes and values on follow-up computed tomography (F/U-CT) for isolated falcine (F-SDH) and tentorial (T-SDH) subdural hematomas (SDHs). METHOD: Fifty-four cases of isolated F-SDH and/or T-SDH were retrospectively reviewed. Subdural hematoma morphology, mass effect on the adjacent parenchyma, and interval change at F/U-CT were evaluated. Subdural hematoma size was measured parallel and perpendicular to the falx/tentorium (long or short axis, respectively). RESULTS: Short-axis increase on F/U-CT was seen only in 5 F-SDHs (16%) and 7 T-SDHs (19%), with a maximum of a 2-mm increase. Long-axis growth was more prominent and frequent, seen in 18 F-SDH patients (56.2%) and 19 T-SDH patients (51.4%), with maximum change of up to 43 mm. Falcine SDH and T-SDH were ipsilateral and contiguous in 77.8% of patients. Minimal mass effect was seen in 13 patients (24.1%), which was resolved or stable on F/U-CT. Anticoagulation did not affect SDH size. No patients required neurosurgery or died. CONCLUSIONS: Based on our limited data, the current standard of F/U-CT may be unnecessary in patients with isolated F-SDH and/or T-SDH, which expand minimally along the short axis without a significant mass effect. Characteristic anatomic structure of the tentorium and falx, and their connectivity may direct SDH expansion and limit mass effect as well as injury to the adjacent parenchyma.

Improving the detection of ventricular shunt disruption using volume-rendered three-dimensional head computed tomography.

Hydrocephalus is the most common neurosurgical disorder in children, and cerebrospinal fluid (CSF) diversion with shunt placement is the most commonly performed pediatric neurosurgical procedure. CT is frequently used to evaluate children with suspected CSF shunt malfunction to assess change in ventricular size. Moreover, careful review of the CT images is important to confirm the integrity of the imaged portions of the shunt system. Subtle shunt disruptions can be missed on multiplanar two-dimensional (2-D) CT images, especially when the disruption lies in the plane of imaging. The use of volume-rendered CT images enables radiologists to view the extracranial shunt tubing within the field of view as a three-dimensional (3-D) object. This allows for a rapid and intuitive method of assessing the integrity of the extracranial shunt tubing. The purpose of this pictorial essay is to discuss how volume-rendered CT images can be generated to evaluate CSF shunts in the pediatric population and to provide several examples of their utility in diagnosing shunt disruption. We also address the potential pitfalls of this technique and ways to avoid them.

Gadolinium retention: should pediatric radiologists be concerned, and how to frame conversations with families.

Gadolinium retention in the brain and other organs has recently been identified by imaging and confirmed histologically. No direct clinical effects of gadolinium retention, which occurs after gadolinium-based contrast agent (GBCA) administration for MRI, have been scientifically accepted at this time. However, there is understandable concern among medical professionals and the public about the potential effects of gadolinium retention, particularly in the brain. Part of this concern might stem from the identification of nephrogenic systemic fibrosis caused by GBCAs in people with severe renal failure in 2006. This article briefly describes the characteristics of GBCAs; reviews and differentiates gadolinium retention, nephrogenic systemic fibrosis, and "gadolinium deposition disease" or "gadolinium toxicity"; and discusses societal guidelines and current usage in children. With the belief that GBCAs should not be withheld for appropriate indications in the absence of evidence of its potential risks, we offer a framework for determining when GBCA use is appropriate and suggestions for discussing its risks and benefits with children and their families.

Applying Artificial Intelligence to Mitigate Effects of Patient Motion or Other Complicating Factors on Image Quality.

Artificial intelligence, particularly deep learning, offers several possibilities to improve the quality or speed of image acquisition in magnetic resonance imaging (MRI). In this article, we briefly review basic machine learning concepts and discuss commonly used neural network architectures for image-to-image translation. Recent examples in the literature describing application of machine learning techniques to clinical MR image acquisition or postprocessing are discussed. Machine learning can contribute to better image quality by improving spatial resolution, reducing image noise, and removing undesired motion or other artifacts. As patients occasionally are unable to tolerate lengthy acquisition times or gadolinium agents, machine learning can potentially assist MRI workflow and patient comfort by facilitating faster acquisitions or reducing exogenous contrast dosage. Although artificial intelligence approaches often have limitations, such as problems with generalizability or explainability, there is potential for these techniques to improve diagnostic utility, throughput, and patient experience in clinical MRI practice.

Practical Considerations for Radiologists in Implementing a Patient-friendly MRI Experience.

For many patients, numerous unpleasant features of the magnetic resonance imaging (MRI) experience such as scan duration, auditory noise, spatial confinement, and motion restrictions can lead to premature termination or low diagnostic quality of imaging studies. This article discusses practical, patient-oriented considerations that are helpful for radiologists contemplating ways to improve the MRI experience for patients. Patient friendly scanner properties are discussed, with an emphasis on literature findings of effectiveness in mitigating patient claustrophobia, other anxiety, or motion and on reducing scan incompletion rates or need for sedation. As shorter scanning protocols designed to answer specific diagnostic questions may be more practical and tolerable to the patient than a full-length standard-of-care examination, a few select protocol adjustments potentially useful for specific clinical settings are discussed. In addition, adjunctive devices such as audiovisual or other sensory aides that can be useful distractive approaches to reduce patient discomfort are considered. These modifications to the MRI scanning process not only allow for a more pleasant experience for patients, but they may also increase patient compliance and decrease patient movement to allow more efficient acquisition of diagnostic-quality images.

The Dancing Cord: Inherent Spinal Cord Motion and Its Effect on Cord Dose in Spine Stereotactic Body Radiation Therapy.

BACKGROUND: Spinal cord dose limits are critically important for the safe practice of spine stereotactic body radiotherapy (SBRT). However, the effect of inherent spinal cord motion on cord dose in SBRT is unknown. OBJECTIVE: To assess the effects of cord motion on spinal cord dose in SBRT. METHODS: Dynamic balanced fast field echo (BFFE) magnetic resonance imaging (MRI) was obtained in 21 spine metastasis patients treated with SBRT. Planning computed tomography (CT), conventional static T2-weighted MRI, BFFE MRI, and dose planning data were coregistered. Spinal cord from the dynamic BFFE images (corddyn) was compared with the T2-weighted MRI (cordstat) to analyze motion of corddyn beyond the cordstat (Dice coefficient, Jaccard index), and beyond cordstat with added planning organ at risk volume (PRV) margins. Cord dose was compared between cordstat, and corddyn (Wilcoxon signed-rank test). RESULTS: Dice coefficient (0.70-0.95, median 0.87) and Jaccard index (0.54-0.90, median 0.77) demonstrated motion of corddyn beyond cordstat. In 62% of the patients (13/21), the dose to corddyn exceeded that of cordstat by 0.6% to 13.8% (median 4.3%). The corddyn spatially excursed outside the 1-mm PRV margin of cordstat in 9 patients (43%); among these dose to corddyn exceeded dose to cordstat >+ 1-mm PRV margin in 78% of the patients (7/9). Corddyn did not excurse outside the 1.5-mm or 2-mm PRV cord cordstat margin. CONCLUSION: Spinal cord motion may contribute to increases in radiation dose to the cord from SBRT for spine metastasis. A PRV margin of at least 1.5 to 2 mm surrounding the cord should be strongly considered to account for inherent spinal cord motion.

Gentle Touch: Noninvasive Approaches to Improve Patient Comfort and Cooperation for Pediatric Imaging.

Pediatric imaging presents unique challenges related to patient anxiety, cooperation, and safety. Techniques to reduce anxiety and patient motion in adults must often be augmented in pediatrics, because it is always mentioned in the field of pediatrics, children are not miniature adults. This article will review methods that can be considered to improve patient experience and cooperation in imaging studies. Such techniques can range from modifications to the scanner suite, different ways of preparing and interacting with children, collaborating with parents for improved patient care, and technical advances such as accelerated acquisition and motion correction to reduce artifact. Special considerations for specific populations including transgender patients, neonates, and pregnant women undergoing fetal imaging will be described. The unique risks of sedation in children will also be briefly reviewed.

Making Magnets More Attractive: Physics and Engineering Contributions to Patient Comfort in MRI.

Patient comfort is an important factor of a successful magnetic resonance (MR) examination, and improvements in the patient's MR scanning experience can contribute to improved image quality, diagnostic accuracy, and efficiency in the radiology department, and therefore reduced cost. Magnet designs that are more open and accessible, reduced auditory noise of MR examinations, light and flexible radiofrequency (RF) coils, and faster motion-insensitive imaging techniques can all significantly improve the patient experience in MR imaging. In this work, we review the design, development, and implementation of these physics and engineering approaches to improve patient comfort.

What Neuroradiologists Need to Know About Radiation Treatment for Neural Tumors.

Radiation oncologists and radiologists have a unique and mutually dependent relationship. Radiation oncologists rely on diagnostic imaging to locate the tumor and define the treatment target volume, evaluation of response to therapy, and follow-up. Accurate interpretation of post-treatment imaging requires diagnostic radiologists to have a basic understanding of radiation treatment planning and delivery. There are various radiation treatment modalities such as 3D conformal radiation therapy, intensity modulated radiation therapy and stereotactic radiosurgery as well as different radiation modalities such as photons and protons that can be used for treatment. All of these have subtle differences in how the treatment is planned and how the imaging findings might be affected. This paper provides an overview of the basic principles of radiation oncology, different radiation treatment modalities, how radiation therapy is planned and delivered, how knowledge of this process can help interpretation of images, and how the radiologist can contribute to this process.

Updates in the Neuoroimaging and WHO Classification of Primary CNS Gliomas: A Review of Current Terminology, Diagnosis, and Clinical Relevance From a Radiologic Prospective.

As new advances in the genomics and imaging of CNS tumors continues to evolve, a standardized system for classification is increasingly essential to diagnosis and management. The molecular markers introduced in the 2016 WHO classification of CNS tumors bring both practical and conceptual advances to the characterization of gliomas, strengthening the prognostic and predictive value of terminology while shedding light on the underlying mechanisms that drive biologic behavior. The purpose of this article is to provide a succinct overview of primary intracranial gliomas from a neuroradiologic prospective and according to the 5th edition WHO classification that was revised in 2016. An update of the molecular markers pertinent to defining the major lineages of brain gliomas will be provided, followed by discussion of the terminology, grading and imaging features associated with individual entities. Neuroradiologists should be aware of the key genomic and radiomic features of common brain gliomas, and familiar with an integrated approach to their diagnosis and grading.

Breast diseases in children: the spectrum of radiologic findings in a cohort study.

PURPOSE: We aimed to investigate the spectrum of radiologic findings and referral reasons for breast diseases in children considering age-appropriate presentation. METHODS: Our retrospective cohort study included 348 consecutive pediatric patients aged <19 years (median, 13 years) referred to radiology with a clinical presentation between 2005 and 2016. Radiologic findings were reviewed in four age ranges (0-2 years, 2-8 years, 8-15 years, >15 years). RESULTS: Of 348 patients, 257 had a referral reason. The most frequent referral reason was a palpable mass (35%). Developmental abnormalities accounted for 48% of all radiologic findings in 348 patients. We did not detect any breast malignancy. According to age groups, the most common radiologic findings were neonatal hypertrophy (0-2 years), early breast development (2-8 years), developmental abnormalities by a majority of gynecomastia (8-15 years), and normal findings or developmental abnormalities (>15 years). Interestingly, the frequency of gynecomastia was only 4% in neonatal period or early childhood. Fibroadenomas and fibroadenoma-like solid masses were seen after 8 years and constituted the majority of solid masses (65%). Cysts were seen at a rate of 7% and majority of them were of simple type, which tends to resolve in time. CONCLUSION: In our study, the most common referral reason to radiology was a palpable breast mass. Neonatal hypertrophy and early breast development in younger children, and developmental abnormalities in older children may be kept in mind as the most common radiologic findings. Our study confirms the substantial absence of malignancies in children as well as a widely different disease spectrum in comparison with the adult population.

Intrathyroidal ectopic thymus in children: a sonographic survey.

AIMS: Intrathyroidal ectopic thymus (IET) is being increasingly reported in the radiology literature. Most of the reports are of individual cases or small series and prevalence and natural course of the pathology is not well known. The purpose of this study is to establish the prevalence of IET in children and report long term follow-up results. MATERIAL AND METHODS: In 180 children who were examined by ultrasound (US) for other reasons, 7 patients were indentified with IET. Together with the other seven children who were already under follow-up for IET (diagnosed using US criteria), these 14 patients were followed up with US for 30 months. Size, shape, location, echotexture and internal echoes of the lesions were evaluated. RESULTS: There were 16 lesions in 14 children. The most common appearance was a fusiform hypoechoic lesion, with punctate and linear internal echoes and well-defined but slightly irregular borders located posteriorly in the lower thirds of the thyroid. In follow-up, there were no changes in echotexture, shape or border. In 3 patients, the lesion became slightly smaller, in a 10-year-old boy slightly larger, and in an 11-year old boy the lesion disappeared. In a patient with bilateral lesions, one lesion slightly decreased in size. CONCLUSIONS: IET in children may be more common than thought. Its growth reflects that of a normal thymus. Awareness of this entity is important in order not to misdiagnose them, especially as papillary cancer, and to prevent unnecessary interventions.

Hydatid disease located in the cerebellomedullary cistern.

Hydatid disease is an endemic zoonotic disease in many areas of the world. Liver, followed by lung, is the most commonly affected organ and involvement of other organs is rare. When brain is involved, lesions are typically supratentorial, and infratentorial localisation is even rarer. We present a 45-year-old woman with hydatid disease located in premedullary location compressing the brain stem, an exceedingly rare location for cerebral echinococcosis. Relevant literature regarding typical properties of cerebral disease was reviewed.