Prevalence of exclusively and concomitant pelvic fractures at magnetic resonance imaging of suspect and occult hip fractures

Pelvic fractures may occur together with hip fractures as a result of low energy trauma. It is unclear whether they do require special attention. There are conflicting results in the literature about the prevalence of both concomitant hip and pelvic fractures as well as exclusive pelvic fractures. It has been reported that hip fractures and obturator ring fractures are mutually exclusive. To retrospectively analyze the prevalence of exclusively pelvic as well as concomitant hip and pelvic fractures in patients examined with MRI after low-energy trauma in elderly. During 9 years, 316 elderly patients had been examined with MRI for suspected or occult hip fracture after a fall. A fracture was diagnosed when MRI showed focal signal abnormalities in the subcortical bone marrow, with or without disruption of adjacent cortices. One observer reviewed all studies. A second observer verified all studies with hip fractures. Follow-up was available for all but two patients that died prior to hip surgery. The prevalence of concomitant pelvic and femoral neck or trochanteric fractures was statistically compared using chi-squared test for categorical variables. Hip fractures were found in 161 (51 %) patients of which 29 (9 %) had concomitant pelvic fractures. There were exclusively pelvic fractures in 82 (26 %) patients of which 65 (79 %) were on the traumatized side only. In 73 patients, there were no fractures. Occult or suspected hip fractures are not infrequently associated with pelvic fractures. Exclusively pelvic fractures are not uncommon.     

眼色素膜黑色素瘤的CT与MRI研究

目的研究色素膜黑色素瘤的ＣＴ和ＭＲＩ表现，探讨最佳ＭＲＩ的扫描序列。材料与方法１５例患者用各种ＭＲＩ序列进行扫描，其中１１例行ＣＴ扫描，并与手术病理进行对照。结果ＣＴ示９例表现为与眼外肌等密度的肿块，２例肿瘤太小未能显示。ＭＲＩ示１４例具有典型的短Ｔ１、短Ｔ２信号，１例３ｍｍ高度的虹膜黑色素瘤在Ｔ１ＷＩ上未能显示；１１例伴有视网膜脱离，呈短Ｔ１及长Ｔ２信号，与肿瘤在Ｔ１ＷＩ上很难区分。使用脂肪抑制和增强扫描的Ｔ１ＷＩ能较好地显示较小肿瘤（高度＜５ｍｍ）能区分肿瘤及其伴发的视网膜脱离。结论ＭＲＩ显示黑色素瘤的准确率和特异性较ＣＴ和Ｂ超优越。     

Computed tomography versus magnetic resonance imaging of the brain. A collaborative interinstitutional study

A retrospective study (1983-1984) of magnetic resonance imaging (MRI) and computed tomography (CT) examinations in 471 patients with known pathology in the brain and craniocervical junction was conducted in order to determine the relative efficacy of MRI versus CT. All MRI examinations involved slice thickness greater than 10 mm, and only single-slice single-echo or multislice single-echo imaging techniques were available. These studies were evaluated independently by two neuroradiologists from a panel of six for anatomic abnormalities, lesion contrast, and radiologist's impression. Results, which excluded microadenomas of the pituitary and approximately 9% of studies in which consensus was not achieved by the readers, were as follows: (1) 14% of the studies were positive on MRI but normal on CT; (2) in 55% of the studies, MRI was better than CT; (3) MRI was equal or better than CT in 95% of the studies; and (4) CT was better than MRI in 5% (21/421) of the examinations. There were no patients in this series where CT was positive but MRI missed the abnormality.     

Added value of interpreter experience in occult and suspect hip fractures: a retrospective analysis of 254 patients

The influence of experience in categorizing suspect and occult fractures on radiography compared to MRI and clinical outcome has not been studied. The aim of this study is to evaluate the importance of experience in diagnosing normal or suspect hip radiographs compared to MRI. Primarily reported normal or suspect radiography in 254 patients with low-energy hip trauma and subsequent MRI was re-evaluated by two experienced reviewers. Primary readings and review were compared. The prevalence of fractures among normal and suspect radiographic studies was assessed. Clinical outcome was used as reference. At review of radiography, 44 fractures (17 %) were found. Significantly more fractures were found among suspect cases than among normal cases. At MRI, all 44 fractures were confirmed, and further 64 fractures were detected (25 %). MRI detected all fractures with no missed fractures revealed at follow-up. There were a significantly higher proportion of fractures at MRI among the suspect radiographic diagnoses for both the primary report and at review than among occult cases. The more experienced reviewers classified radiography examinations with higher accuracy than primary reporting general radiologists. There was almost complete agreement on MRI diagnoses.     

Computed tomography and magnetic resonance imaging of mediastinal tumors

We describe the clinical, pathological, and imaging findings of mediastinal tumors with focus on thymic hyperplasia, thymic epithelial tumors, and germ cell tumors, malignant lymphoma, and various cystic masses. Chemical shift magnetic resonance imaging (MRI) is useful in characterization of the normal thymus and differentiation of hyperplastic thymus and thymic tumors. In contrast to noninvasive thymomas, invasive thymomas and thymic carcinomas show a more aggressive growth pattern. Local invasion and pleural spread are characteristic of invasive thymoma and mediastinal lymphadenopathy and distant metastasis suggest thymic carcinomas. Mature teratoma typically shows various computed tomography (CT) attenuation, and MR signal intensity depending on its contents and fat tissue and bone within the lesions are its characteristic findings. Seminomas typically have homogenous internal CT attenuation and MR signal intensity with minimal contrast enhancement. Nonseminomatous malignant germ cell tumors characteristically show prominent internal degenerative changes and invasion to the adjacent structures. In mediastinal lymphomas, a residual mass is common after treatment and MRI provides important information in distinguishing viable tumors from residual benign masses. Some mediastinal cysts may reveal high attenuation similar to solid lesions on CT depending on their contents and MRI can be useful in the differentiation of cystic masses from solid lesions.     

Computed tomography and magnetic resonance imaging of the pericardium

Computed tomography is an established modality for the evaluation of the pericardium. It is used to evaluate complicated pericardial effusions, pericardial thickening, calcific pericarditis, pericardial cysts, postoperative changes and primary and metastatic neoplasms of the pericardium. Magnetic resonance imaging is being used with increasing frequency in the evaluation of pericardial disease. It offers advantages over computed tomography, including a potential for tissue characterization, absence of ionizing radiation or need for intravenous contrast medium, and the ability to scan in any plane. Disadvantages include greater cost, longer examination times and the inability to identify calcification positively.     

Computed tomography and magnetic resonance imaging of the orbital apex

This article describes the CT and MR appearance of the orbital apex and masses in this region. The sectional anatomy by axial, coronal, and sagittal planes as well as the thin-layer technique used to accomplish this is detailed first. Then the application of these techniques to the presence of tumors is illustrated and discussed.     

Computed tomography and magnetic resonance imaging diagnosis of thymic cyst

A case of mediastinal thymic cyst evaluated by computed tomography and magnetic resonance imaging is presented. The anterior mediastinal mass was well-demarcated and measured 10 Hounsfield units on the computed tomographic scan. The lesion showed intermediate signal intensity on T1-weighting and became hyperintense on T2-weighted images. These computed tomography and magnetic resonance imaging features suggested a cystic structure, which proved to be a benign thymic cyst on pathologic examination.     

Computed tomography and magnetic resonance imaging findings of acquired dacryocystoceles

In this study, radiological findings of acquired dacryocystocele are presented. A total of 13 dacryocystoceles including bilateral in two of the patients, in four patients on the left and in five patients on the right, were determined. Six of the patients had dacryocystocele infection. Average density of the non-infected dacryocystoceles was 11.8±7.8 Haunsfield units (HU), while the median density value of infected ones was 35.0 HU. There was expansion on unilateral nasolacrimal duct in four patients. Acquired dacryocystoceles are rare masses in medial canthal area, and their radiological imaging findings may vary based on etiological factors and presence of infections.     

Computed tomography and magnetic resonance imaging evaluation of patellofemoral instability

Malalignment and tracking abnormalities of the patellofemoral joint are common causes of anterior knee pain,which are often difficult to evaluate clinically. Conventional radiography, as well as the cross-sectional imaging modalities of computed tomography (CT) and magnetic resonance imaging (MRI) are useful tools for both detecting and quantifying these abnormalities. Acute transient dislocation of the patella, on the other hand, is a relatively uncommon injury accounting for only 2% to 3% of all acute injuries of the knee, and can also be a difficult diagnosis to establish on the basis of history and physical findings alone. MRI is a sensitive, noninvasive method for detecting prior acute transient dislocation of the patella. This article begins by describing the role of CT and MRI as it pertains to the detection of abnormal patellofemoral tracking. Both static and dynamic techniques are described along with the standard criteria used to establish and quantify patellofemoral malalignment abnormalities. Next, the constellation of MRI findings most commonly encountered after acute transient dislocation of the patella are described. These findings include a typical bone bruise pattern involving the anterolateral aspect of the lateral femoral condyle and inferomedial patella, hemarthrosis, and injury to the medial soft-tissue restraints (especially the medial patellofemoral ligament). After transient dislocation of the patella, patients with significant osteochondral injury or disruption of the medial soft-tissue restraints may benefit from surgical repair. The role of MRI in preoperative planning is discussed as it relates to the detection of osteochondral injuries as well as injury to the medial soft-tissue restraints.     

Computed tomography and magnetic resonance imaging findings in cerebral hydatid disease

Purpose: The purpose of this study was to describe the discriminative computed tomography (CT) and magnetic resonance imaging (MRI) features of cerebral hydatid disease.Methods: The CT and MRI findings of four cases of surgically proven cerebral hydatid cysts were retrospectively reviewed. Results: CT demonstrated well-defined cystic lesions with no perilesional oedema and no contrast enhancement in all cases except one recurrent disease that showed both peripheral oedema and rim enhancement. MR images revealed well-defined cystic lesions with a quite clear rim that showed relative hypointensity limited to some aspects of the cyst walls on T2-weighted images. The cysts were spherical and obvious mass effect was observed on both CT and MR examinations. Conclusions: Although the cystic nature of intracranial hydatid disease could be equally well demonstrated on CT and MR examinations, CT is superior in detecting calcification of the cyst wall or septa, when present, and MR is better in demonstrating cyst capsule, detecting multiplicity and defining the anatomic relationship of the lesion with the adjacent structures and helps in surgical planning.     

Computed tomography and magnetic resonance imaging in cystic fibrosis lung disease

Computed tomography (CT) is the current "gold standard" for assessment of lung morphology and is so far the most reliable imaging modality for monitoring cystic fibrosis (CF) lung disease. CT has a much higher radiation exposure than chest x-ray. The cumulative radiation dose for life-long repeated CT scans has limited its use for CF patients as their life expectancy increases. Clearly, no dose would be preferable over low dose when the same or more relevant information can be obtained. Magnetic resonance imaging (MRI) is comparable to CT with regard to the detection of most morphological changes in the CF lung. It is thought to be less sensitive to detect small airway disease. At the same time, MRI is superior to CT when it comes to the assessment of functional changes such as altered pulmonary perfusion. The recommendation is to further reduce radiation dose related to the use of CT and to use MRI in the follow-up of morphological changes where possible.     

Computed tomography and magnetic resonance imaging of the female lower urinary tract.

Computed tomography (CT) and magnetic resonance (MR) imaging have become invaluable imaging modalities in the diagnosis of diseases involving the lower urinary tract. Both CT and MR imaging are able to accurately stage bladder carcinoma, with MR imaging able to distinguish between superficial and deep muscle invasion of tumor. CT and MR are also the studies of choice for evaluating retroperitoneal fibrosis, which often affects the urinary tract; MR imaging is often able to detect the presence of active inflammation and occasionally rule out a malignant cause. MR imaging holds promise for the evaluation of stress urinary incontinence and urethral disease. Although diseases of the distal ureter continue to be most accurately diagnosed by intravenous urography and retrograde studies, CT and MR imaging may serve a helpful secondary role.     

Computed tomography and magnetic resonance imaging in the preoperative work-up for cochlear implantation.

The role of CT and MRI in the evaluation of patients for possible insertion of a multichannel intracochlear hearing device was appraised. The study included 52 patients who underwent both CT and MRI examinations, 40 of whom were later operated on. Coronal and axial T2-weighted spin-echo sequences were performed in 25 volunteers with normal hearing and in 47 adult patients. In 5 patients, instead of a T2-weighted spin-echo sequence, a T2*-weighted gradient echo 3D sequence with axial presaturation was used. In 39 patients with normal appearances on CT and MRI, the implant device was successfully inserted. One patient who underwent surgery had a reduced cochlear signal on MRI but a normal CT scan; however, at surgery, the implant device could only be inserted into the first turn of the cochlea, due to fibrous obliteration. In 3 of 12 patients who were not operated upon, the results of diagnostic imaging indicated that the insertion of an intracochlear hearing device was not useful. Our experience indicates that, with reduced cochlear fluid signal intensities on MRI, fibrous obliteration of the cochlear turns is likely to be present. MRI proved to be a useful adjunct to CT, but the latter was necessary for the evaluation of bony abnormalities. Gradient echo sequences can successfully replace time-consuming T2-weighted spin-echo sequences.     

Computed tomography and magnetic resonance imaging findings of soft tissue perineurioma

Soft tissue perineurioma is an uncommon benign peripheral nerve sheath tumor, although it is the most common subtype of perineuriomas. We present a case of soft tissue perineurioma in the left groin of a 48-year-old man. Precontrast computed tomography showed a homogeneous hypodense mass that showed faint enhancement. The mass appeared with hypointensity on T1-weighted magnetic resonance (MR) images and heterogeneous hyperintensity on T2-weighted MR images. Slight contrast uptake was noted on enhanced T1-weighted MR images with fat suppression. Although these CT and MR imaging findings were nonspecific, the overall imaging features are similar to those of schwannomas.     

Computed tomography and magnetic resonance imaging of dilated lumbar lymphatic trunks

We report a patient in whom computed tomography (CT) scanning demonstrated bilateral para-aortic lesions, originally misinterpreted as lymphadenopathy, but shown by a combination of CT, lymphangiography and magnetic resonance imaging to represent dilated lumbar lymphatic trunks. This case illustrates a further para-aortic lesion which may be mistaken for lymphadenopathy on cross-sectional imaging.     

Computed tomography and magnetic resonance imaging of lesions at masticator space

We aim to review the normal anatomy and imaging appearance of masticator space lesions. Because the masticator space is not amenable to direct examination, cross-sectional imaging with computed tomography and magnetic resonance imaging play an important role in diagnosis and characterization of lesions occurring there. Masticator space lesions can be classified on the basis of their origin into the following categories: inflammatory lesions, benign tumors, malignant tumors, vascular lesions, and developmental lesions. A diverse spectrum of malignant tumors and benign lesions are seen extending from the adjacent spaces. In addition, one should also be familiar with pseudolesions as well as post-treatment changes in the masticator space that can be mistaken for pathologic conditions.