Magnetic resonance imaging in multiple sclerosis: results in 32 cases

A prospective clinical study was performed in 32 patients with multiple sclerosis (MS) to evaluate the sensitivity of lesion detection and accuracy of lesion localization by neurologic examination, delayed enhanced computed tomography (CT) with a double dose of contrast material, and proton magnetic resonance (MR) imaging. After neurologic examination patients were classified by probability of MS (possible, four patients; probable, three patients; and definite, 25 patients) and by disease activity (acute, chronic with acute exacerbation, or chronic progressive). Subsequently they underwent delayed enhanced CT scanning and MR imaging with more than one spin-echo technique. In five of seven patients with possible or probable MS, both MR imaging and delayed enhanced CT were negative. In 25 cases of definite MS, MR imaging detected pathology in 19 (76%) cases, while CT detected lesions in 15 (60%) of 25 cases. In acute lesions (acute or chronic with acute exacerbation), the two techniques were of similar sensitivity (delayed CT was positive in 65% and MR imaging in 60%), while in chronic progressive MS, MR imaging was superior in lesion detection (MR imaging positive in 75%; delayed CT in 25%). While most lesions (55%) were seen in corresponding locations in both studies, neither MR nor delayed CT correlated well with lesion localization by neurologic examination because a large number of asymptomatic lesions were imaged and many symptomatic lesions were undetected.(ABSTRACT TRUNCATED AT 250 WORDS)     

海洛因依赖的影像学表现分析

目的：分析海洛因依赖者的影像学表现,并提高对本病的认识。方法：本组海洛因依赖者39例中,无神经系统症状组26例和产生神经系统症状组13例分别行MRI和／或CT扫描。结果：无神经系统症状组中MRI表现正常,产生神经系统症状组则出现明显的特征性MRI和CT改变,即对称性大脑半球脑白质、内囊后支、小脑、胼胝体、脑干改变。结果：当海洛因依赖病人出现神经系统症状时,头频MRI和CT的表现具有特征性。     

CT and MRI diagnosis of silent sinus syndrome

Purpose

The purpose of this study was to determine computed tomography (CT) and magnetic resonance (MR) findings of silent sinus syndrome (SSS) — a rare clinical entity with the constellation of progressive enophthalmos and hypoglobus, facial asymmetry and possible diplopia — due to otherwise asymptomatic maxillary sinus disease.

Materials and methods

We reviewed the pre- and postoperative CT and MR images of six patients with a definitive diagnosis of SSS and compared the radiological and clinical findings with those reported in the literature.

Results

The CT and MR studies demonstrated in all cases the most characteristic imaging features of SSS reported in the literature.

Conclusions

Both CT and MR imaging enable a diagnosis of SSS to be made, but CT provides a better depiction of all features of SSS necessary for diagnosis and differentiation from other sinus conditions, even in patients without a clinical suspicion of SSS.     

Malignant hyperphenylalaninemia: CT and MR of the brain

A defect in biopterin synthesis not only prevents the transformation of phenylalanine to tyrosine (as in classical phenylketonuria, PKU) but also blocks the biosynthesis of the neurotransmitters dopamine, norepinephrine, and serotonin, causing severe neurologic disturbances. The brain CT and MR findings in this rare disorder have not been described. In the present series, eight patients with PKU were all examined with CT, three were also examined with MR imaging. In spite of severe clinical findings, CT was normal or almost normal in three patients; in three other children, moderate loss of brain volume was found. White matter disease was found in three patients (moderate in two and severe in one) and was also found in an additional patient with classical PKU. PKU should therefore be added to the list of possible causes for white matter disease. Furthermore, biopterin-dependent PKU should be considered when the CT examination in a child with severe neurologic manifestation only shows discrete pathology.     

MR imaging of white matter disease in children

Twenty-three pediatric patients with white matter abnormalities on MR images were evaluated retrospectively to assess the contribution of MR compared with CT in diagnosing these conditions. In addition, the MR findings in major categories of white matter diseases were analyzed for sensitivity in detecting the presence of an abnormality. White matter disease categories included demyelinating disease (five cases), dysmyelinating disease (eight cases), developmental white matter abnormalities (four cases), and white matter abnormalities of unknown origin (idiopathic) (six cases), as seen on long TR images. We found that MR is not more sensitive than CT in detecting disease in the demyelinating or dysmyelinating categories, although it is more sensitive than CT in detecting the degree of disease present. In cases of developmental delay, MR is distinctly more useful than CT in demonstrating abnormalities of myelination. And in the idiopathic group, MR detected the presence of focal white matter abnormalities on long TR images in children with neurologic complaints and normal CT. MR may serve to redefine and broaden the spectrum of reported imaging abnormalities in pediatric patients.     

Imaging strategies for MR of the brain

MR has emerged as the imaging modality of choice for the brain in patients presenting with seizures, chronic headaches, progressive neurologic deficits, ataxia, vertigo, hearing loss, visual loss, congenital abnormalities, signs of increased intracranial pressure, dementia, suspected multiple sclerosis, and in the vast majority of other elective neurologic problems. CT should currently be considered the primary imaging modality in patients with acute neurologic deficits (stroke), acute onset of severe headaches, and when fine bone detail is required. Acutely injured patients are more readily studied with CT. The vast majority of patients in whom CT is preferred are seen in emergent situations, frequently in hospital emergency rooms. The effects of trauma beyond the acute stage are best evaluated with MR. In the future, MR is likely to become the procedure of choice in even more clinical situations than at present. A summary of currently recommended primary imaging modalities in various clinical situations is provided in Table 1.     

Early diagnosis of spinal metastases by CT and MR studies

Fifteen patients with known metastatic or high-risk primary cancer, normal neurologic examinations, and new abnormalities on 99mTc bone scan were evaluated with spinal CT and magnetic resonance (MR) imaging. Four patients underwent CT metrizamide myelography. Spinal CT and MR agreed in 14 of 15 patients demonstrating spinal metastases in 12 patients and benign disease in two. In one patient spinal CT was normal, but MR showed altered marrow signal consistent with metastatic disease. Epidural tumor was demonstrated by CT metrizamide myelography in four cases, all correctly identified by MR. Further evaluation of spinal MR in this setting is warranted.     

MRI新技术在肺及气道病变中的应用研究进展

目前先天性心脏病(CHD)合并肺及气道病变的诊断主要依靠CT,但MRI因其无电离辐射、软组织分辨力高而极具优势。近年来不断出现的MRI新技术新序列逐渐克服传统MRI序列在显示肺及气道病变方面的局限性,其中三维快速场回波(3D-TFE)序列、三维平衡快速场回波(3D-B-TFE)序列可以清晰显示气道,超短回波时间(UTE)序列主要用于肺成像。这3种MRI新序列独特的成像优势使得MRI在CHD合并气道和肺病变的应用成为可能,也进一步实现了安全、无创、高效的疾病诊断。     

Assessment of transient ischemic attack with diffusion- and perfusion-weighted imaging

BACKGROUND: Diagnosing TIA can be difficult, since evidence of brain ischemia is habitually lacking on CT and conventional MR imaging. It has been suggested that patients with acute brain infarction on neuroimaging should be considered stroke cases instead of TIA, regardless of duration of symptoms, implying that optimal diagnostic methods need to be utilized. We therefore postulated that perfusion-weighted MR imaging (PW imaging) would be useful in the diagnosis of TIA. METHODS: Retrospective analysis of 22 patients with reversible neurologic symptoms lasting less than 24 hours, assessed with DW and PW imaging. RESULTS: MR imaging was abnormal in 15 patients (68%): 12 had abnormal DW imaging, four had both DW and PW imaging defects (all with a mismatch) and three had an isolated PW imaging abnormality. There were no differences in symptom duration, stroke etiology or cardiovascular risk factors between patients with abnormal MR imaging and those with unremarkable scan. Patients with mismatch were more likely to need conventional angiography or other cerebrovascular procedures. CONCLUSION: The combined use of DW imaging and PW imaging provided evidence of brain ischemia in most patients with clinical diagnosis of TIA. Prospective studies using follow-up MR imaging are required to determine the outcome of affected tissue, as well as the clinical implications of DW-PW imaging abnormalities.     

Computed tomography and magnetic resonance tomography of rectal and sigmoid tumors

CT and MR imaging are of minor importance for the preoperative diagnosis of rectosigmoid carcinoma. A synchronous colon tumor can be excluded with a barium enema, while an accurate diagnosis of liver metastases is possible using real-time ultrasonography. However, post-operative management requires the use of tomographic methods: MR imaging has proved to be more accurate than CT for differentiation between local recurrence and post-operative scars. Therefore MRI should be the method of choice after surgery for rectosigmoid carcinoma in all patients without postoperative baseline examinations.     

Imaging of central nervous system tumors

Magnetic resonance imaging has been used increasingly in the staging and evaluation of neoplasia of the brain and leptomeninges. In the classification of gliomas, the MR accuracy rate approaches that of pathologic diagnosis. Contrast-enhanced MR imaging has improved specificity in evaluating brain tumors in children and is now the preferred modality for evaluating leptomeningeal metastases of the brain and spine. MR imaging in children has also increased the specificity of histologic diagnosis in hypothalamic hamartoma and juvenile pilocytic astrocytoma. Gadolinium enhancement is most useful in patients older than 35 years of age who have focal neurologic complaints and certain disease histories. The expense of gadolinium contrast material is the major drawback to its routine use. In patients with seizure disorder, MR imaging is more sensitive than CT for detecting abnormalities such as mesial temporal sclerosis, tumors, and vascular malformations. Gadolinium enhancement may be useful in differentiating tumors from mesial temporal sclerosis. Recent reports on the use of MR spectroscopy for evaluating brain metabolism and tumors demonstrate that differences in metabolites exist. A correlation was found in epidermoid tumors between high signal on T1-weighted images and high lipid content, and several studies have shown a positive correlation between glioma grade and glycolytic activity as determined on 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography.     

Chronic seizure disorders: contribution of MR imaging when CT is normal

One hundred consecutive patients with complex partial seizures were studied by magnetic resonance (MR) imaging and computed tomography (CT). Thirty-four patients had seizures of more than 5 years' duration, yet neurologic examinations and previous pre- and postinfusion CT scans had been normal. MR imaging demonstrated surgical lesions of potentially therapeutic significance in four of these 34 patients. Two patients underwent surgery with removal of a thrombosed arteriovenous malformation and a glioma. Although CT has been found to detect structural abnormalities, its yield of therapeutically significant abnormalities has been low.     

海洛因白质脑病的CT与MRI诊断

目的 研究CT与MRI对烫吸海洛因蒸汽引起海绵状白质脑病的特征性影像学诊断价值。方法 对2例烫吸海洛因引起的海绵状白质脑病的患者进行了临床和CT与MRI观察，查阅中外文献，对该病影像学特征结合临床表现、病理组织改变进行总结与讨论。结果 2例患者以小脑性共济失调、智力减退为主要临床表现，CT显示对称性分布的小脑白质、大脑白质为主的低密度改变；MRI显示对称性分布的小脑齿状核，大脑半球半卵圆中心、双基底节内囊、中脑、桥脑白质纤维为主的高信号改变。结论 烫吸海洛因引起海绵状白质脑病的CT与MRI影像学改变具有特征性，能为临床诊断提供可靠依据，从而使本病能够得到早期确诊。     

The diagnostic role of abdominal CT imaging findings in adults intussusception: focused on the vascular compromise

Intussusception is defined as telescoping of one segment of the gastrointestinal tract into an adjacent one. Unlike that in children, adult intussusception is a relatively rare condition. More than 90% of patients with adult intussusception have been reported to have an organic cause, with benign or malignant tumors for accounting for approximately 65% of the cases. In general, the diagnosis is easily made by means of computed tomography (CT) or magnetic resonance (MR) imaging. The imaging appearance of a bowel-within-bowel configuration with or without contained fat and mesenteric vessels, is pathognomonic. As the intussusceptum enters into the intussuscipiens, the mesentery is carried forward and trapped between the overlapping layers of bowel. The twisting or severe constriction of the mesenteric vessels may result in vascular compromise with subsequent edematous thickening of the involved bowel. In these circumstances, ischemic necrosis may develop if timely intervention is not undertaken. Therefore, determination of the presence or absence of intestinal necrosis in intussusception is important in patient management. On CT, the presence of well-known diagnostic CT criteria for strangulated obstruction (especially severe engorgement or twisting of the mesenteric vessels) as well as evidence of loss of the layered pattern, accumulation of extraluminal fluid collection, and bowel perforation, may suggest the diagnosis of intestinal necrosis. CT and MR imaging are limited in determining the primary disease causing intussusception. However, CT and MR provide excellent pre-operative evaluation, including the possible extension and/or dissemination of a malignant tumor. CT and MR imaging may also be useful in suggesting the presence of vascular compromise.     

Clinical use of urinary tract magnetic resonance imaging

MR imaging should not be used to evaluate the majority of the lesions described herein but should be reserved for specific clinical situations. The detection and differential diagnosis of adrenal masses is a legitimate application of this technique. The staging of renal tumors in patients in whom CT fails to do so may be accomplished by MR imaging. Establishment of patency of the renal veins and of surgical shunts involving these veins may be performed by MR imaging if Doppler ultrasonography proves unsatisfactory. MR imaging may differentiate between stable retroperitoneal fibrosis and malignant disease in patients in whom this differential is a problem. Hematomas may be distinguished from nonhemorrhagic fluid collections anywhere in the abdomen or pelvis. In selected patients, the local extent of certain bladder tumors may be evaluated by MR imaging when CT and biopsy fail to do so. In testicular disease, MR imaging may aid in the differential diagnosis of abnormalities that are not sufficiently characterized by ultrasonography, and MR imaging may detect undescended testes in some patients in whom ultrasonography fails to do so. In the future, wider application of fast scanning with bolus administration of soluble paramagnetic contrast agents may refine the differential diagnosis of adrenal masses and aid in the detection of renal masses. MR angiographic techniques ultimately may constitute a screening procedure for renal arteriostenosis. A subset of patients with prostate carcinoma may prove to benefit from local staging of the disease by MR imaging.     

Small cell lung cancer: staging with MR imaging

Small cell lung cancer is an aggressive neoplasm; metastases are detected in two-thirds of patients at diagnosis with use of conventional staging, which includes bilateral bone marrow biopsy, bone scintigraphy, and computed tomography (CT) of the head and abdomen. In 25 patients, small cell lung cancer was staged prospectively with both conventional staging and a magnetic resonance (MR) imaging protocol that included 1.5-T MR imaging of the pelvis, abdomen, spine, and brain. According to conventional staging, 14 patients had extensive disease and 11 patients had limited disease; according to staging with MR, 19 patients had extensive disease and six had limited disease. All metastatic disease sites seen with conventional staging were identified on MR images. MR images showed additional metastatic involvement in bone (four patients) and liver (three patients) not detected at conventional staging. A low-attenuation hepatic lesion on a CT scan was identified as a hemangioma on MR images. These preliminary data suggest that small cell lung cancer may be accurately staged with use of a single MR imaging study.     

Masses of the anterior mediastinum: CT and MR imaging

CT and MR imaging allow earlier diagnosis and more specific characterization of anterior mediastinal masses than is possible with plain film radiographs. This review describes state-of-the-art CT and MR imaging of the anterior mediastinum. After a discussion of CT and MR imaging and indications for their use, normal and abnormal CT and MR findings in the anterior mediastinum are reviewed. Abnormalities include benign and malignant neoplasms, cysts, and mediastinal thyroid. Several masses such as thymolipomas, goiters, cysts, and lymphangiomas often do not require removal and now can be diagnosed with reasonable accuracy when imaging results are combined with clinical history. Detection, diagnosis, staging, and follow-up of malignant anterior mediastinal masses are important and have been improved with CT and MR imaging.     

Brachial plexus: correlation of MR imaging with CT and pathologic findings

Thirty-two patients with symptoms referable to the brachial plexus were evaluated with magnetic resonance (MR) imaging. Sixteen patients had undergone concurrent computed tomography (CT). MR imaging demonstrated normal findings in 16, 12 neoplasms, three cases of trauma, and one case of possible neural edema. Of the 16 patients with normal findings on MR images, eight had CT scans that were also normal. In one patient, MR images showed that the "mass" seen on CT was actually a tortuous blood vessel. In six of the 12 cases of neoplasm in which CT scans were available, MR imaging revealed more extensive disease. In the other six cases of tumor, MR imaging provided sufficient clinical information to obviate the need for CT or any other imaging modality. MR imaging provided definitive diagnoses in the three cases of trauma without further imaging. In one patient with paresthesia, MR imaging showed high signal intensity of the nerves on T2-weighted images, which was compatible with neural edema. A concurrent CT scan was normal.     

Acute cervical spine trauma: correlation of MR imaging findings with degree of neurologic deficit

A retrospective analysis of magnetic resonance (MR) imaging studies of 78 patients with acute cervical spinal cord injuries was undertaken to determine which observations related directly to the neurologic injury. All MR imaging studies were performed on a 1.5-T unit and assessed with respect to 14 parameters related to the bony spine, ligaments, prevertebral soft tissues, intervertebral disks, and spinal cord. Forty-eight patients also underwent non-contrast material-enhanced thin-section computed tomography (CT) of the cervical spine. MR imaging was the definitive modality in the assessment of soft-tissue injury, especially in the evaluation of the spinal cord and intervertebral disks. All patients with a neurologic deficit had abnormal spinal cords at MR imaging. Intramedullary hemorrhage was predictive of a complete lesion. The degree of associated bone and soft-tissue injury had no bearing on the extent of spinal cord injury or neurologic deficit. Patients with residual cord compression following reduction demonstrated greater neurologic compromise than those without compression.     

MR imaging and CT of vascular anomalies and connections in patients with congenital heart disease: significance in surgical planning.

To plan effective management of congenital heart disease, one needs the clearest understanding of the anatomy. Although echocardiography and angiography are the dominant imaging modalities in patients with congenital heart disease, magnetic resonance (MR) imaging and computed tomography (CT) are valuable noninvasive adjuncts. MR imaging and CT are effective in demonstrating the complex cardiovascular morphology present in congenital heart disease, especially the extracardiac morphology. In patients with tetralogy of Fallot with complex pulmonary artery anatomy, MR imaging and CT are useful in demonstrating the pulmonary artery anatomy, along with the significant aortopulmonary collateral vessels. In the heterotaxy syndromes, patients often have unusual atriovenous connections. MR imaging allows accurate identification of the hepatic, systemic, and pulmonary veins and their relationships to both atria. CT and MR are the imaging modalities of choice in a patient who is thought to have a vascular ring. Treatment of aortic coarctation is usually performed on the basis of typical clinical and echocardiographic findings. In patients with atypical clinical or echocardiographic findings, MR imaging and CT yield helpful information that can change the treatment plan. The enhanced preoperative understanding of congenital heart disease provided by MR imaging and CT simplifies surgical decision making and consequently may improve outcome.