![]() Bone cancer affects all age groups, but certain subtypes, like osteosarcoma and Ewing sarcoma are more common in children and adolescents, while chondrosarcoma is more common in adults. These mutations can be genetic, spontaneous or induced by environmental factors. What causes bone cancer?īone cancer is caused by mutations in a person’s DNA. Certain rare conditions like Paget’s disease or Maffucci’s syndrome place a person at higher risk to develop bone cancer, but most develop spontaneously. Our understanding of bone cancer continues to progress, but there is no simple way to predict who will develop bone cancer or when it will develop. Malignant bone lesions, or bone cancer, occurs when a cell in the bone is able to multiply without restraint and evade the body’s defenses to destroy this abnormal tissue. The patient’s pacemaker for an unrelated heart condition is also visible. slice-overlap artifact a.k.a.Anteroposterior (front-to-back) X-ray view of a chondrosarcoma (malignant bone tumor) in right proximal humerus (upper arm bone).propylene glycol peak: resonates at 1.13 ppm. ![]() N-acetylaspartate (NAA) peak: resonates at 2.0 ppm.glutamine-glutamate peak: resonates at 2.2-2.4 ppm.gamma-aminobutyric acid (GABA) peak: resonates at 2.2-2.4 ppm.2-hydroxyglutarate peak: resonates at 2.25 ppm.arterial spin labeling (ASL) MR perfusion.dynamic contrast enhanced (DCE) MR perfusion.dynamic susceptibility contrast (DSC) MR perfusion.metal artifact reduction sequence (MARS).turbo inversion recovery magnitude (TIRM).fluid attenuation inversion recovery (FLAIR).diffusion tensor imaging and fiber tractography.MRI pulse sequences ( basics | abbreviations | parameters).It's often performed to help diagnose: Aneurysms of cerebral vessels Disorders of the eye and inner ear Multiple sclerosis Spinal cord disorders Stroke Tumors Brain injury from trauma A special type of MRI is the functional MRI of the brain (fMRI). iodinated contrast-induced thyrotoxicosis MRI is the most frequently used imaging test of the brain and spinal cord.iodinated contrast media adverse reactions.clinical applications of dual-energy CT.as low as reasonably achievable (ALARA).Slice-overlap artifact (also known as cross-talk artifact)įourier transform and Nyquist sampling theorem MRI hardware and room shieldingĪliasing artifact (also known as wrap around artifact) The difference in chemical shift between two nuclei referred to as 1 and 2 is. where is the resonance frequency of a nucleus and REF the resonance frequency of a reference nucleus. Many artifacts have a characteristic appearance, and with experience, they can be readily identified. Recall from the NMR Spectroscopy chapter that the definition of chemical shift,, is. Remember that artifacts are not all bad and that occasionally, they are intentionally exploited, e.g. Hardware issues may cause central point and RF overflow artifacts. Characteristics of pulse sequences may cause black boundary, Moiré, and phase-encoding artifacts. Finite sampling, k-space encoding, and Fourier transformation may cause aliasing and Gibbs artifact. Presence of anatomy outside the image fieldĬlassification of the artifact type may give one an idea about how to try to fix it.Īrtifacts are caused by a variety of factors that may be patient-related, such as voluntary and physiologic motion, metallic implants or foreign bodies. fast spin echo, gradient, volumetric acquisition When encountering an unfamiliar artifact, it is useful to systematically examine general features of the artifact to try and understand its general class. Some artifacts affect the quality of the MRI exam, while others do not affect the diagnostic quality but may be confused with pathology. ![]() ![]() MRI artifacts are numerous and give an insight into the physics behind each sequence. ![]()
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