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Notes: Abstract. Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID=""ID=""〈e5〉Correspondence to:〈/e5〉 T. Fujita

Notes: Examination was made of ultrasonic attenuation α44 and elastic constant C44 of vanadium single crystals with hydrogen between 4.2 and 220 K, as a function of temperature, hydrogen concentration, frequency, and rates of cooling and heating. Attenuation in the V–H α phase at 210 K increased in proportion to the square of hydrogen concentration, while C44 was linear. At a cooling rate of 3.0 K/min, attenuation of the specimen with 1000 at. ppm H increased below the critical solution temperature and showed a peak. At 0.1 K/min, discontinuous decrease was observed at the temperature. During isothermal annealing below this temperature, attenuation at the higher cooling rate decreased with time in two stages and approached the value for the lower cooling rate. The results are discussed based on ultrasonic double refraction due to the volume array of hydrogens and hydride particles formed under the influence of C44-mode ultrasonic waves. © 1996 American Institute of Physics.