Magnetic resonance quarterly最新文献

{"title":"Magnetic resonance imaging in the evaluation of cerebrospinal fluid flow abnormalities.","authors":"W G Bradley","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Phase contrast magnetic resonance imaging techniques can be used to evaluate the to-and-fro motion of cerebrospinal fluid (CSF) throughout the ventricles and subarachnoid space of the brain and spine. This CSF motion is due to transmitted cardiac pulsations from systolic expansion of the cerebral hemispheres. To cover the entire cardiac cycle, retrospective cardiac gating (rather than electrocardiographic triggering) must be used. Using this technique, it is possible to quantify CSF motion over a cardiac cycle and to distinguish normal aqueductal CSF \"stroke volumes\" from those seen in atrophy and shunt-responsive communicating hydrocephalus. Arachnoid cysts and other loculated CSF collections can be diagnosed using a \"rebound sign\" in which the motion of the CSF within the cyst is 90 degrees phase advanced over the CSF flowing around it.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 3","pages":"169-96"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12562550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance imaging of the breast.","authors":"S E Harms,&nbsp;D P Flamig,&nbsp;K L Hesley,&nbsp;W P Evans","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The diagnosis and treatment of breast cancer is dependent upon accurate depiction of the disease by diagnostic imaging. In a number of clinical situations, conventional breast imaging does not adequately address these diagnostic needs. New magnetic resonance imaging (MRI) methods developed specifically for breast diagnosis may provide the additional capability needed to fill the gap between clinical needs and the information obtained by conventional breast imaging methods. Fat-suppressed 3D MRI has demonstrated improved sensitivity over routine breast imaging methods. MRI can also be used to differentiate between certain benign but mammographically suspicious lesions and cancer. The potential clinical roles of MRI are reviewed with clinical examples. Pitfalls in the use of MRI are defined. The problems encountered with the implementation of MRI in a clinical setting are outlined and future advances predicted.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 3","pages":"139-55"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12562548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate): clinical experience with a new contrast agent.","authors":"N M Rofsky,&nbsp;J C Weinreb","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Despite the many imaging techniques available to evaluate the liver, deficiencies persist. The choice of the optimal method is still controversial, with competing issues of safety, efficacy, and cost. Numerous strategies to improve the results of liver imaging have been pursued, including the application of tissue-targeted contrast agents to magnetic resonance imaging (MRI). Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate) (Mn-DPDP) is one of several recently developed hepatobiliary agents, targeted to functioning hepatocytes. The Mn-DPDP-enhanced MRI has demonstrated promise in the clinical trials. Contrast-to-noise measurements have shown favorable results for Mn-DPDP-enhanced MR compared to non-enhanced T1- and T2-weighted images. The ability to characterize tumors of hepatocellular origin and an improved capability for lesion detection have also been demonstrated. Furthermore, the prolonged enhancement obtained with Mn-DPDP has extended the time during which effective contrast is maintained. Importantly, no clinically significant adverse events have been demonstrated. This report will detail the clinical experience with Mn-DPDP-enhanced MRI of the abdomen.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 3","pages":"156-68"},"PeriodicalIF":0.0,"publicationDate":"1992-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12562549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance imaging of the foot and ankle.","authors":"J B Kneeland,&nbsp;M K Dalinka","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Technical considerations for the magnetic resonance imaging of the foot and ankle are discussed, including the selection of the appropriate surface coil, the importance of stabilizing the anatomic region, and the principles guiding the choice of pulse sequences. The anatomy of the foot and ankle are reviewed, and the normal appearance and important variations of the different structures on magnetic resonance images are discussed. Pathology of the foot and ankle are then discussed. Topics covered include osteochondral and radiographically occult fractures, tears and inflammation of the Achilles and posterior tibial tendons, tears of the lateral collateral ligaments and sinus tarsi syndrome, primary tumors (in particular, those of the foot), synovial diseases such as pigmented villonodular synovitis, congenital abnormalities, and disorders such as tarsal tunnel syndrome and plantar fasciitis.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 2","pages":"97-115"},"PeriodicalIF":0.0,"publicationDate":"1992-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12789845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance imaging of the wrist.","authors":"M B Zlatkin,&nbsp;T Greenan","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Magnetic resonance (MR) imaging has developed rapidly as a diagnostic tool in the evaluation of the wrist. In this article, the authors review simple high-resolution technique and appropriate surface coils to aid in wrist evaluation. Evaluation of the wrist is facilitated by an understanding of the anatomy of the carpal ligaments, the triangular fibrocartilage, and the carpal tunnel, and the anatomic features of the distal radioulnar joint. Triangular fibrocartilage tears, which represent an important cause of ulnar wrist pain, are well evaluated on MR. These appear as a linear band of increased signal on the short repetition time/echo time (TR/TE), proton density weighted spin echo, or gradient echo images. True tears should be differentiated from degenerative changes, which do not demonstrate increase in signal on T2 or T2* weighted images. With good technique, accuracies approaching 90% have been reported. MR is also useful in evaluating injuries of the interosseous ligaments and volar and dorsal radiocarpal ligaments and distal radioulnar joint instability. MR also has a role in evaluating the carpal tunnel syndrome. This is especially true with patients for whom symptoms suggest the diagnosis of carpal tunnel syndrome but for whom few objective findings exist. Findings suggestive of carpal tunnel syndrome include diffuse swelling of the median nerve, flattening of the median nerve at the level of the hamate, and increased signal of the median nerve on the long TR/TE images. MR is also indicated in avascular necrosis of the carpal bones and occult carpal fractures. MR is useful in evaluating bone tumors, particularly with regard to their extent. With the advent of more rapid scanning techniques, kinematic studies are feasible. For these, fast gradient echo techniques are employed and serial images are acquired during radial and ulnar deviation. These images may be helpful in observing integrity of intercarpal ligaments and evaluating dynamic instability. With proper attention to technique, and an understanding of wrist pathophysiology, MR is a valuable diagnostic tool.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 2","pages":"65-96"},"PeriodicalIF":0.0,"publicationDate":"1992-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12789844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetization transfer contrast in magnetic resonance imaging.","authors":"R S Balaban,&nbsp;T L Ceckler","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Magnetization transfer contrast (MTC) in magnetic resonance imaging (MRI) is the result of selectively observing the interaction of bulk water protons with the protons contained in macromolecules of a tissue. Since different tissues have different macromolecular compositions, the MTC can generate very high tissue contrast that is based on well-defined physiochemical properties. This is accomplished by combining a saturation transfer technique with standard MRI procedures. The specific practical and theoretical aspects of saturation transfer as it applies to the generation of MTC are reviewed and discussed. In the last 3 years, MTC has been applied to the study of the body, with useful applications demonstrated in evaluating the morphology of the knee joint, eye, brain, breast, and heart. The application of MTC to accentuate MR angiography and contrast agent studies has also been demonstrated. Thus, MTC is becoming another tool towards maximizing the quality and diagnostic potential of MRI. Recent studies on isolated macromolecules have suggested that the MTC effect is specific to the surface chemistry and correlation time of the macromolecules. These latter results indicate that the magnetization transfer process may provide a unique quantitative method of MR tissue characterization based on macromolecule dynamics and chemistry.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 2","pages":"116-37"},"PeriodicalIF":0.0,"publicationDate":"1992-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12789840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Drug targeting in magnetic resonance imaging.","authors":"R Weissleder,&nbsp;A Bogdanov,&nbsp;M Papisov","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This review summarizes the attempts of drug targeting in the field of magnetic resonance imaging. Although the field is young and most work is performed in nonspecific lanthanide chelates, it is obvious that target selectivity and receptor and/or antigen specificity is the most important issue if functional magnetic resonance imaging is to establish itself in the next decade. Recent advances in biochemical engineering and magnetic resonance research have made targeting of diagnostic drugs a credible alternative to conventional drug use in magnetic resonance imaging.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 1","pages":"55-63"},"PeriodicalIF":0.0,"publicationDate":"1992-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12735311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic resonance angiography in the body.","authors":"J P Finn,&nbsp;A Goldmann,&nbsp;R R Edelman","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Magnetic resonance angiography (MRA) is gaining wide acceptance as a clinical tool for evaluation of the carotid arteries and intracranial circulation. MR angiographic methods are far less widely employed in the body. However, several very powerful techniques have been developed which provide a wealth of clinical information and which may soon replace alternative imaging techniques for a variety of applications. As compared with MRA of the head and neck, these techniques require more interactive involvement by a physician and more familiarity with the imaging machine to derive their full benefit. Based on the experience of the authors and others working in the field, this article outlines strategies for MRA of the abdomen, pelvis and thorax, and reviews the clinical situations in which these techniques have proved useful.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 1","pages":"1-22"},"PeriodicalIF":0.0,"publicationDate":"1992-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12735309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The postoperative knee.","authors":"A L Deutsch,&nbsp;J H Mink,&nbsp;J M Fox,&nbsp;M J Friedman,&nbsp;S M Howell","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Magnetic resonance (MR) has established itself as the gold standard for noninvasive imaging of the knee. As in arthroscopy, assessment of injuries to the menisci, articular surfaces, synovium, and cruciate ligaments can be made. Additionally, MR has an advantage over arthroscopy in being able to assess the para articular soft tissues and cortical and medullary bony compartments. Until recently, the role of MR in the postoperative knee has been less clear. New information, however, suggests that MR is capable of assessing the status of the partially resected meniscus, the adjacent articular surfaces, and subchondral medullary lesions that frequently occur. There has been recent interest in reestablishment of the stabilizing function of a previously torn anterior cruciate ligament by means of autogenous or allogenous materials. MR permits the surgeon to assess the isometry and possible sites of graft impingement that may occur following cruciate ligament reconstruction. The purpose of this article is to define the current status of MR in the assessment of the postoperative knee.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"8 1","pages":"23-54"},"PeriodicalIF":0.0,"publicationDate":"1992-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12735310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential diagnosis of hepatic neoplasms: spin echo versus gadolinium-diethylenetriaminepentaacetate-enhanced gradient echo imaging.","authors":"Y A Abbas,&nbsp;H Y Kressel,&nbsp;F W Wehrli,&nbsp;W B Gefter,&nbsp;B J Dinsmore,&nbsp;T W Chan,&nbsp;L Oleaga,&nbsp;B N Milestone,&nbsp;E K Outwater","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Early results are reported of hepatic neoplasms studied with dynamic gadolinium-diethylenetriaminepentaacetate (Gd-DTPA)-enhanced magnetic resonance imaging (MRI). The purpose of this study was to evaluate the potential of the Gd enhancement pattern for characterizing these neoplasms and to compare the performance of spin-echo (SE) to SE plus dynamic Gd-enhanced gradient-echo (GRE) pulse sequences. Forty-two patients with hepatic neoplasms were examined at 1.5 T field strength. In each patient, short and long repetition time/echo time (TR/TE) SE images were obtained, followed by pre- and post-Gd-DTPA (0.1 mmol/kg body wt), single-slice, breath-hold (13 s/scan) GRE images, which were serially acquired less than or equal to 12 min postinjection. The patterns of contrast enhancement of the various hepatic lesions were documented and analyzed. The time to peak Gd signal enhancement-to-noise ratio (SE/N), contrast-to-noise ratio (C/N), contrast (defined as the signal intensity ratio [SIR]), as well as the peak values of these quantities, were determined. The C/N and SIR values on the short and long TR/TE SE and pre-Gd GRE images for all hepatic neoplasms were also obtained. The discriminating abilities (hemangiomas vs. malignant neoplasms) of these quantities were analyzed statistically. In addition, the impact of lesion characterization on the SE versus the SE plus the Gd-enhanced GRE scans was assessed by means of a blinded reader study. Malignant hepatic neoplasms could be differentiated from hemangiomas by visual inspection of their enhancement patterns (p = 0.0009), by the time to peak C/N on Gd-enhanced images (p = 0.0002), and by the magnitude of such peak (p = 0.02). Combined SE + Gd-enhanced GRE scans afforded minor, though statistically significant (p less than 0.01), improvement of the accuracy in differentiating benign from malignant hepatic neoplasms. Late scans (12 min post-Gd) may be particularly useful in identifying hemangiomas that, unlike other neoplasms, have a significant high signal of their enhancing portions on such images.</p>","PeriodicalId":77248,"journal":{"name":"Magnetic resonance quarterly","volume":"7 4","pages":"275-92"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"12953252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}