Search

Objectives and Methods: Large intracranial calcifications are occasionally encountered in routine computed tomography (CT) scans of the brain. These calcifications, also known as "brain stones", can be classified according to location and aetiology. Combining imaging findings with relevant clinical history and physical examination can help narrow down the differential diagnosis and may allow confident diagnosis in certain situations., Results: This article provides a pictorial review illustrating various clinical entities resulting in brain stones., Discussion: Based on location, brain stones can be classified as extra- or intra-axial. Extra-axial brain stones comprise tumours and exaggerated physiological calcifications. Intra-axial brain stones can further be classified according to aetiology, namely neoplastic, vascular, infectious, congenital and endocrine/metabolic. Imaging findings combined with essential clinical information can help in narrowing the differential diagnosis, determining disease state and evaluating effect of therapy., Teaching Points: • Based on location, brain stones can be either extra- or intra-axial. • Extra-axial brain stones comprise tumours and exaggerated physiological calcifications. • Intra-axial aetiologies include neoplastic, vascular, infectious, congenital and endocrine/metabolic. • CT scan is the mainstay in identifying and characterising brain stones. • Certain MRI sequences (gradient echo T2* and susceptibility-weighted imaging) are considered adjunctive.

Objective: The purpose of this article is to illustrate the utility of susceptibility-weighted imaging (SWI) as an adjunct to routine MRI of the brain in neurologic disorders., Conclusion: SWI is a 3D spoiled gradient-echo sequence that combines phase and magnitude information to provide a high sensitivity for the detection of blood degradation products, calcifications, and iron deposits.

Purpose: To examine the T(2)-normal appearing spinal cord of patients with multiple sclerosis (MS) using diffusion tensor imaging., Materials and Methods: Diffusion tensor images of the spinal cord were acquired from 21 healthy subjects, 11 MS patients with spinal cord lesions, and 10 MS patients without spinal cord lesions on the T(2)-weighted MR images. Different diffusion measures were evaluated using both a region of interest (ROI) -based and a diffusion tensor tractography-based segmentation approach., Results: It was observed that the FA, the transverse diffusivity lambda(perpendicular), and the ratio of the longitudinal and transverse diffusivities (lambda(parallel)/lambda (perpendicular)) were significantly lower in the spinal cord of MS patients with spinal cord lesions compared with the control subjects using both the ROI method (P = 0.014, P = 0.028, and P = 0.039, respectively) and the tractography-based approach (P = 0.006, P = 0.037, and P = 0.012, respectively). For both image analysis methods, the FA and the lambda (parallel)/lambda (perpendicular) values were significantly different between the control group and the MS patient group without T(2) spinal cord lesions (P = 0.013)., Conclusion: Our results suggest that the spinal cord may still be affected by MS, even when lesions are not detected on a conventional MR scan. In addition, we demonstrated that diffusion tensor tractography is a robust tool to analyze the spinal cord of MS patients., ((c) 2009 Wiley-Liss, Inc.)

Purpose: To compare region of interest (ROI)-based and diffusion tensor tractography (DTT)-based methods for evaluating diffusion properties of the spinal cord as a function of age., Materials and Methods: Commonly, an ROI segmentation is used to delineate the spinal cord. In this work, new segmentation methods are developed based on DTT. In a first, DTT-based, segmentation approach, the diffusion properties are calculated on the tracts. In a second method, the diffusion properties are analyzed in the spinal cord voxels that contain a certain number of tracts. We studied the changes in diffusion properties of the human spinal cord in subjects of different ages. Diffusion tensor imaging (DTI) measurements of the cervical spinal cord were acquired on 42 healthy volunteers (age range = 19-87 years). The fractional anisotropy (FA), the mean diffusivity (MD), and eigenvalues (lambda(1), lambda(2), and lambda(3)) were compared for the ROI- and DTT-based segmentation methods., Results: Our automatic techniques are shown to be highly reproducible and sensitive for detecting DTI changes. FA decreased (r = -0.38; P < 0.05), whereas MD and eigenvalues increased (r = +/- 0.45; P < 0.05) with age. These trends were not statistically significant for the ROI-based segmentation (P > 0.05)., Conclusion: DTT is a robust and reproducible technique to segment the voxels of interest in the spinal cord., ((c) 2008 Wiley-Liss, Inc.)

Scoliosis is a structural lateral curvature of the spine with a rotatory component. Imaging in scoliosis is important. Most cases of scoliosis are idiopathic, and imaging is used routinely in monitoring the changes of the deformity that take place during growth. Imaging is also crucial in determining the underlying etiology in non-idiopathic cases of scoliosis and is used in pre- and postoperative monitoring.

Because it may cause paralysis, injury to the spine is one of the most feared traumas, and spinal cord injury is a major cause of disability. In the USA approximately 10,000 traumatic cervical spine fractures and 4000 traumatic thoracolumbar fractures are diagnosed each year. Although the number of individuals sustaining paralysis is far less than those with moderate or severe brain injury, the socioeconomic costs are significant. Since most of the spinal trauma patients survive their injuries, almost one out of 1000 inhabitants in the USA are currently being cared for partial or complete paralysis. Little controversy exists regarding the need for accurate and emergent imaging assessment of the traumatized spine in order to evaluate spinal stability and integrity of neural elements. Because clinicians fear missing occult spine injuries, they obtain radiographs for nearly all patients who present with blunt trauma. We are influenced on one side by fear of litigation and the possible devastating medical, psychologic and financial consequences of cervical spine injury, and on the other side by pressure to reduce health care costs. A set of clinical and/or anamnestic criteria, however, can be very useful in identifying patients who have an extremely low probability of injury and who consequently have no need for imaging studies. Multidetector (or multislice) computed tomography (MDCT) is the preferred primary imaging modality in blunt spinal trauma patients who do need imaging. Not only is CT more accurate in diagnosing spinal injury, it also reduces imaging time and patient manipulation. Evidence-based research has established that MDCT improves patient outcome and saves money in comparison to plain film. This review discusses the use, advantages and disadvantages of the different imaging techniques used in spinal trauma patients and the criteria used in selecting patients who do not need imaging. Finally an overview of different types of spinal injuries is given.

Evaluation of the intracranial circulation provides valuable information in the diagnosis and prognosis of various intracranial abnormalities and may influence patient management. Technical advances in magnetic resonance angiography (MRA) have improved the accuracy of this technique in various clinical situations, such as aneurysms, arterial and venous steno-occlusive diseases, vascular malformations, inflammatory arterial diseases, preoperative assessment of the patency of dural sinuses, and congenital vascular abnormalities. In many centers, MRA has replaced conventional digital subtraction angiography in screening for intracranial vascular disease, because of its non-invasive and non-ionizing character. Several MRA techniques have been developed for the imaging of the intracranial vascular system, such as time-of-flight MRA (TOF MRA), phase-contrast MRA (PC MRA), and more recently contrast-enhanced MRA (CE MRA). In the evaluation of steno-occlusive disease, the three-dimensional (3D) TOF-MRA technique is recommended for arterial evaluation, and the 2D TOF or 2D PC-MRA technique for venous evaluation. For the evaluation of aneurysms and arteriovenous malformations (AVMs), we recommend the 3D CE-MRA technique, especially dynamic sequences in case of AVM. In this review, the technical aspects, limitations, and optimization of these MRA techniques will be discussed together with their indications in intracranial disease.

Shaken-baby syndrome (SBS) is a type of child abuse caused by violent shaking of an infant, with or without impact, and characterized by subdural hematomas, retinal hemorrhages, and occult bone fractures. Parenchymal brain lesions in SBS may be missed or underestimated on CT scans, but can be detected at an earlier stage with diffusion-weighted MRI (DW-MRI) as areas of restricted diffusion. We demonstrate the value of DW-MRI in a 2-month-old baby boy with suspected SBS. The pattern of diffusion abnormalities indicates that the neuropathology of parenchymal lesions in SBS is due to hypoxic-ischemic brain injuries, and not to diffuse axonal injury.

Objectives: To review clinical and radiological findings in patients with Duret hemorrhages and to discuss the pathophysiology and differential diagnosis of these lesions., Patients and Methods: We reviewed the case records of four patients with Duret hemorrhages who had been admitted to the neurological intensive care unit with supratentorial mass lesions., Results: Descending transtentorial and subfalcine herniations were present in all cases. Three patients were admitted with acute subdural hematoma and one with intraparenchymal hemorrhage. Computed tomography revealed the presence of blood in the mesencephalon and upper pons. Three patients died; one survived with severe disabilities., Discussion: Duret hemorrhages are typically located in the ventral and paramedian aspects of the upper brainstem (mesencephalon and pons). The pathophysiology of Duret hemorrhage remains under debate: arterial origin (stretching and laceration of pontine perforating branches of the basilar artery), versus venous origin (thrombosis and venous infarction). Multifactorial causation seems likely., Conclusion: Duret hemorrhages are delayed, secondary brainstem hemorrhages. They occur in craniocerebral trauma victims with rapidly evolving descending transtentorial herniation. Diagnosis is made on computed tomography of the brain. In most cases the outcome is fatal. On the basis of our observations we believe that arterial hypertension and advanced age are risk factors for the development of Duret hemorrhage.