1,721,076 research outputs found
Problems and errors of magnetic resonance in the diagnosis of renal masses
No full textSince the impact of MRI on the diagnostic evaluation of renal masses is affected by the intrinsic complexity of the modality, the problems related to the specific knowledge, on the part of the radiologist, of the examination itself to make a correct diagnosis are carefully analyzed. The problems related to the technical features of the equipment are presented as well, with a special emphasis on the still inadequate spatial resolution of MRI, and on its long acquisition time and unfavorable signal-to-noise ratio. On the other hand, its good contrast resolution is mentioned, which will be further improved by the new gradient-echo sequence (GRE) and by the use of paramagnetic contrast media. As for diagnostic problems, the results are analyzed of a series of 62 patients showing US "solid" renal mass. MRI allowed lesion detection in 59/62 cases, with 95.1% sensitivity. False negatives were due solely to the poor image quality determined by motion artifacts. MRI did not provide significant information in the structural evaluation of the lesions when tissue characterization was concerned, but was helpful in the correct assessment of necrotic foci (thus allowing the calculation of viable neoplastic mass) and in the detection of collateral vessels. Finally, the spatial relationships of the mass could be easily assessed by MRI, thanks to both its multiplanarity and to its good capabilities in the visualization of vascular involvement
Musculoskeletal MRI at 7 T: do we need more or is it more than enough?
Full text linkUltra-high field magnetic resonance imaging (UHF-MRI) provides important diagnostic improvements in musculoskeletal imaging. The higher signal-to-noise ratio leads to higher spatial and temporal resolution which results in improved anatomic detail and higher diagnostic confidence. Several methods, such as T2, T2*, T1rho mapping, delayed gadolinium-enhanced, diffusion, chemical exchange saturation transfer, and magnetisation transfer techniques, permit a better tissue characterisation. Furthermore, UHF-MRI enables in vivo measurements by low-γ nuclei (23Na, 31P, 13C, and 39K) and the evaluation of different tissue metabolic pathways. European Union and Food and Drug Administration approvals for clinical imaging at UHF have been the first step towards a more routinely use of this technology, but some drawbacks are still present limiting its widespread clinical application. This review aims to provide a clinically oriented overview about the application of UHF-MRI in the different anatomical districts and tissues of musculoskeletal system and its pros and cons. Further studies are needed to consolidate the added value of the use of UHF-MRI in the routine clinical practice and promising efforts in technology development are already in progress
2D fast phase contrast: valutazione del flusso nelle arterie renali normali e stenotiche.
No full textMagnetic resonance of the temporomandibular joint: experience at an Italian university center
No full textAIM: The aim of this investigation was to suggest criteria in order to evaluate magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). Such criteria have been discussed on the basis of our experience at the Section of Prosthetic Dentistry, Department of Neurosciences, University of Pisa. METHODS: The study sample was constituted by 135 patients. All subjects underwent bilateral MRI of the TMJs to evaluate disc structure and position, bony structure abnormalities, joint effusion localization and entity. RESULTS: MRI allowed depiction of the articular disc in 98.9% of the TMJs, showing a normal disc structure in 91.1% of the cases and abnormal in 7.7%. The disc-condyle relationship was normal in 46.6% TMJs, while a disc displacement with reduction was revealed in 35.5% cases, a disc displacement without reduction in 16.7% and a posterior disc displacement in 1.5% joints. In the coronal images, the disc was positioned lateral to the condyle in 8.9% of the TMJs and medial in 6.7%. Osseous abnormalities have been found in 177 joints (65.5%), with cases of bony flattening (condyle and/or tuberculum), erosions, subchondral cysts, osteophytosis and sclerosis. T2 sequences showed effusion in 26.7% of the TMJs. CONCLUSIONS: These findings suggest that standardized methodology application and well-defined criteria can facilitate MR imaging observations and interpretation as well as the diagnosis of intra-articular pathologies
A Metastatic Squamous Cell Carcinoma in a Diabetic Foot: Case Report
No full textA 72-year-old male was referred to our hospital for a plantar ulceration that had occurred many years earlier. The lesion, with exuberant granulation and large areas of necrosis and fibrin, had long been treated by plastic surgeons with no positive evolution. At admission in our hospital no ischemia was detected, and foot radiograph was negative for bone involvement. The patient underwent a foot magnetic resonance imaging, which showed high vascularization in the plantar region and early capture of the contrast medium. We then performed multiple biopsies of the ulceration that revealed a moderately differentiated squamous cell carcinoma. The total body computed tomography exam raised a systemic involvement. A lymph node biopsy and immunohistochemistry assay on the pleural cytological sample proved the presence of a primary squamous cell carcinoma of the foot with systemic dissemination. Although rare, squamous cell carcinoma could be associated with chronic nonhealing ulcers; therefore, when a lesion does not heal, despite adequate standard treatment, its etiopathogenesis should be challenged
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