Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Ungewöhnliche Strahlenreaktion nach Röntgenweichstrahltherapie bei einer Patientin mit Pemphigus vulgaris

Zusammenfassung Bei einer 71j?hrigen Frau trat nach R?ntgenweichstrahltherapie an der Nase (Gesamtdosis 28 Gy, Gewebehalbwerttiefe 10,5–11,5 mm) eine ausgepr?gte Strahlenerosion auf. Diese zeigte 5 Wochen nach Ende der Bestrahlung noch keine Tendenz zur Abheilung. Ursache dieses ungew?hnlichen Verlaufes war ein gleichzeitig bestehender Pemphigus vulgaris. Dieser hatte sich nach der Strahlentherapie, vermutlich als Folge einer Freisetzung epidermaler Antigene, verschlimmert. Da? der Pemphigus in diesem Fall durch die Bestrahlung ausgel?st wurde – wie mehrfach in der Literatur berichtet – ist unwahrscheinlich, aber nicht sicher auszuschlie?en. Eingegangen am 11. April 1994 Angenommen am 10. Juni 1994     

FM sonography in diffuse liver disease: prospective assessment and blinded analysis

FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.