Acta radiologica
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Six pigs with coronary artery occlusion were investigated with MR imaging before and subsequently for about 2.5 hours at repeated intervals after the intravenous administration of Gd-DTPA (0.4 mmol/kg). The animals were sacrificed after a total occlusion time of 6 hours and the hearts were excised. The excised hearts were then reexamined in the MR equipment and stained with TTC (triphenyl tetrazolium) in order to define areas of infarction. ⋯ Ex vivo, without any contrast media, the infarctions were poorly discriminated with a discretely increased signal intensity relative to normal myocardium in the T2 weighted images. Gd-DTPA was found to accumulate in the infarctions, which caused an elevated signal intensity most pronounced in the T1 weighted images. This considerably improved the delineation of the infarcted area.
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The influence of flip angle and TR on signal to noise ratio and contrast between cerebrospinal fluid (CSF) and cord was evaluated in cervical spine imaging in 5 volunteers, using gradient echo technique. All experiments were performed on a 0.3 tesla Fonar beta-3000 M scanner using solenoidal surface coils. The most useful sequence was considered to be TR/TE = 300/12 ms and 10 degrees flip angle. ⋯ The sequence was also evaluated in 10 patients with degenerative disease and in 5 with lesions in the cord. The gradient echo sequence was found to be equal to or better than short and long TR/TE spin echo sequences in demonstrating narrowing of the spinal canal and cord lesion. The drawback is the limited signal to noise ratio.
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The results of chest radiography in 581 patients with blunt minor thoracic trauma were reviewed. Frontal and lateral views of the chest indicated pathology in 72 patients (12.4%). ⋯ The physical examination and the results of chest radiography were not in accordance because in 6 (30%) of the 20 patients with hemo/pneumothorax the physical examination was normal. Consequently there is wide indication for chest radiography after minor blunt chest trauma.
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Comparative Study
Radiography and ultrasonography in paranasal sinusitis.
In order to analyze whether ultrasonography with a reasonable degree of confidence can replace radiography in the diagnosis of sinusitis, 138 patients with clinical signs of sinusitis were examined with both methods. It was found that maxillary sinus fluid was recognized ultrasonographically with a confidence that increased with the amount of fluid, judged from radiographic examinations. In a sub-group of 45 cases, fluid confirmed by maxillary sinus puncture was detected by ultrasonography in 35/45 sinuses (78%) and by radiology in 38/45 sinuses (84%). ⋯ However, mucosal swelling and polyps or cysts observed at radiography were poorly demonstrated by ultrasonography. In addition, the ultrasound method was not reliable for frontal sinus diagnosis. It was concluded that ultrasonography can be recommended in maxillary sinusitis for follow-up of treatment and as a screening method before sinus radiography.