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Rahal, Andrés; Head, Hayden W.; Jung, Adam J.; Garcia-Rojas, Xavier; Vargas, Daniel; Dalrymple, Neal C.; Clarke, Geoffrey D.; Dodd, Gerald D.; Fullerton, Gary D.
doi: 10.1148/radiol.2451070168pmid: 17885177
Hammoud, Dima A.; Hoffman, John M.; Pomper, Martin G.
doi: 10.1148/radiol.2451060731pmid: 17885179
The use of molecular imaging techniques in the central nervous system (CNS) has a rich history. Most of the important developments in imaging—such as computed tomography, magnetic resonance imaging, single photon emission computed tomography, and positron emission tomography—began with neuropsychiatric applications. These techniques and modalities were then found to be useful for imaging other organs involved with various disease processes. Molecular imaging of the CNS has enabled scientists and researchers to understand better the basic biology of brain function and the way in which various disease processes affect the brain. Unlike other organs, the brain is not easily accessible, and it has a highly selective barrier at the endothelial cell level known as the blood-brain barrier. Furthermore, the brain is the most complex cellular network known to exist. Various neurotransmitters act in either an excitatory or an inhibitory fashion on adjacent neurons through a multitude of mechanisms. The various neuronal systems and the myriad of neurotransmitter systems become altered in many diseases. Some of the most devastating diseases, including Alzheimer disease, Parkinson disease, brain tumors, psychiatric disease, and numerous degenerative neurologic diseases, affect only the brain. Molecular neuroimaging will be critical to the future understanding and treatment of these diseases. Molecular neuroimaging of the brain shows tremendous promise for clinical application. In this article, the current state and clinical applications of molecular neuroimaging will be reviewed.
Modic, Michael T.; Ross, Jeffrey S.
doi: 10.1148/radiol.2451051706pmid: 17885180
The sequelae of disk degeneration are among the leading causes of functional incapacity in both sexes and are a common source of chronic disability in the working years. Disk degeneration involves structural disruption and cell-mediated changes in composition. Mechanical, traumatic, nutritional, and genetic factors all may play a role in the cascade of disk degeneration, albeit to variable degree in different individuals. The presence of degenerative change is by no means an indicator of symptoms, and there is a very high prevalence in asymptomatic individuals. The etiology of pain as the symptom of degenerative disease is complex and appears to be a combination of mechanical deformation and the presence of inflammatory mediators. The role of imaging is to provide accurate morphologic information and influence therapeutic decision making. A necessary component, which connects these two purposes, is accurate natural history data. Understanding the relationship of etiologic factors, the morphologic alterations, which can be characterized with imaging, and the mechanisms of pain production and their interactions in the production of symptoms will require more accurate and reproducible stratification of patient cohorts.
Leone, Antonio; Guglielmi, Giuseppe; Cassar-Pullicino, Victor N.; Bonomo, Lorenzo
doi: 10.1148/radiol.2451051359pmid: 17885181
Intervertebral instability of the lumbar spine is thought to be a possible pathomechanical mechanism underlying low back pain and sciatica and is often an important factor in determining surgical indication for spinal fusion and decompression. Instability of the lumbar spine, however, remains a controversial and poorly understood topic. At present, much controversy exists regarding the proper definition of the condition, the best diagnostic methods, and the most efficacious treatment approaches. Clinical presentation is not specific, and the relationship between radiologic evidence of instability and its symptoms is controversial. Because of its simplicity, low expense, and pervasive availability, functional flexion-extension radiography is the most thoroughly studied and the most widely used method in the imaging diagnosis of lumbar intervertebral instability. In this article, we provide an overview of the current concepts of vertebral instability, focusing on degenerative lumbar intervertebral instability, and review the different imaging modalities most indicated in diagnosing vertebral instability.
Bartella, Lia; Thakur, Sunitha B.; Morris, Elizabeth A.; Dershaw, D. David; Huang, Wei; Chough, Eugenia; Cruz, Maria C.; Liberman, Laura
doi: 10.1148/radiol.2451061639pmid: 17885182
Purpose: To prospectively evaluate the sensitivity and specificity of proton (hydrogen 1 1 H) magnetic resonance (MR) spectroscopy for diagnosing malignant enhancing nonmass lesions identified at breast MR imaging, with histologic examination as the reference standard. Materials and Methods: In this HIPAA-compliant, institutional review board–approved study, in which all participants gave written informed consent, proton ( 1 H) MR spectroscopy of the breast was performed in suspicious or biopsy-proved malignant lesions that were 1 cm or larger at MR imaging. Single-voxel proton ( 1 H) MR spectroscopic data were collected. MR spectroscopic findings were defined as positive if the signal-to-noise ratio of the choline resonance peak was 2 or greater and as negative in all other cases. MR spectroscopic results were then compared with histologic findings, and statistical analysis was performed. Results: In 32 women (median age, 48.5 years range, 20–63 years) with enhancing nonmass lesions, the median lesion size at MR imaging was 2.8 cm (range, 1.2–9.0 cm). At histologic analysis, 12 (37%) of 32 lesions were malignant and 20 (63%) were benign. Positive choline findings were present in 15 of 32 lesions, including all 12 (100%) cancers and three (15%) of 20 benign lesions, giving proton ( 1 H) MR spectroscopy a sensitivity of 100% (95% confidence interval CI: 74%, 100%) and a specificity of 85% (95% CI: 62%, 97%) for detection of enhancing nonmass lesions. For 25 lesions with unknown histologic features, proton ( 1 H) MR spectroscopy would have significantly ( P < .01) increased the positive predictive value of biopsy from 20% to 63%. If biopsy had been performed for only those lesions with positive choline findings at proton ( 1 H) MR spectroscopy, biopsy might have been avoided for 17 (68%) of 25 lesions, and no cancers would have been missed. Conclusion: Proton ( 1 H) MR spectroscopy had 100% sensitivity and 85% specificity for the detection of malignancy in enhancing nonmass lesions.
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