PURPOSE:We evaluated the usefulness of an agent for contrast-enhanced ultrasonography (galactose parmitine acid: Levovist) in visualizing brain perfusion in rabbits.MATERIALS AND METHODS:Six rabbits were involved in this study. A hole in the skull bone was made under anesthesia and used as an acoustic window. An ischemic model (3 of 6 rabbits) was made by surgically occluding the M1 portion of the middle cerebral artery. Power Doppler images (PDI) and B-mode Harmonic images (HI) before and after intravenous injections of the contrast medium (150 mg/body) were obtained using the HDI5000 (ATL) equipped with a linear-type 5-12 Mhz probe.RESULTS:Smaller arteries were clearly visualized by contrast-enhanced PDI. However, enhancement of brain parenchyma was not clear on PDI. Enhancement of brain parenchyma was observed clearly on contrast-enhanced HI. Enhancement was strong during the first pass and then diminished quickly. In ischemic models, hypoperfusion in the right cerebral hemisphere (the occluded side) were clearly observed on contrast-enhanced HI.CONCLUSION:Brain perfusion in rabbits can be observed on contrast-enhanced Harmonic ultrasonographic imaging. It is suggested to be useful for human clinical cases, including hypoxic ischemic brain injury in infants.

PURPOSE:We evaluated the clinical usefulness of the Cho/Cr ratio of proton MR spectroscopy(1H-MRS) to differentiate residual/recurrent glioma from non-neoplastic lesions.PATIENTS AND METHODS:20 cases of glioma were involved in this study(astrocytoma grade I-II: 7, oligodendroglioma: 1, astrocytoma grade III: 2, glioblastoma: 10). Seven of the patients underwent surgical resection only, 4 underwent surgical resection and radiotherapy(40-60 Gy), and 9 underwent surgical resection and radiotherapy with concurrent chemotherapy(14-60 Gy). 1H-MRS was performed on a 1.5 Tesla clinical MR unit using a 3D-chemical shift imaging sequence(1500 msec/270 msec/1 (TR/TE/excitations), and the Cho/Cr ratio was calculated in the voxel where neoplastic lesion was most suspected on MRI. The presence of lactate + lipid peak was also evaluated. All spectra were obtained after the contrast enhanced study.RESULTS:Cho/Cr ratios were significantly higher in cases of residual/recurrent tumors(mean +/- SD = 1.70 +/- 0.96) than in non-neoplastic lesions(mean +/- SD = 1.04 +/- 1.16) (Mann-Whitney U-test p = 0.047). If a Cho/Cr ratio of more than 1.5 was used as a marker of tumor presence, its sensitivity was 64%, specificity 83%, and accuracy 70%. One false-positive case that of radiation necrosis whose spectrum showed a high Cho/Cr ratio with markedly elevated lactate + lipid peak.CONCLUSION:The Cho/Cr ratio of 1H-MRS provides additional information to MRI in differentiating residual/recurrent gliomas from non-neoplastic lesions.

We report a rare case of intravascular lymphomatosis with massive tumor in the superior sagittal sinus (SSS), which caused sinus thrombosis. A 63-year-old man was incidentally found to have an enhancing mass in the superior sagittal sinus on MRI. The tumor manifested spontaneous regression during with 4 month's follow-up. Five months after the initial MR examination, T2-weighted MR images revealed a area of hyperintensity in the right occipital lobe. The area showed hypointensity on diffusion-weighted image and showed hyperintensity on ADC mapping, findings that are compatible with vasogenic edema.

Choroid plexus carcinoma(CPC) is a rare intracranial neoplasm that usually arises in the supra-tentorial region of infants. We report an adult case of CPC that arose in the foramen Luschka. A 61-year-old woman presented with a 10-year history of dysarthria. CT showed an iso- to slightly high density mass in the left foramen Luschka. The tumor appeared as a low- to iso-intensity area in T1-weighted MR images, and as an iso- to high-intensity area in T2-weighted images. The tumor showed homogeneous enhancement with the administration of contrast medium. Imaging findings were non-specific and the differential diagnosis was difficult.

Elongated styloid process syndrome, which is synonymous with Eagle's syndrome, is a rare disease. Although an elongated styloid process is not always symptomatic, if it compresses the cranial nerves and/or carotid artery, a patient can present with sore throat, dysphasia, or dysphoria of the throat. We present two cases of elongated styloid process syndrome, focusing on the imaging findings. The elongated styloid processes were visualized by panoramic photograms. However, CT images, especially 3DCT images, were useful in visualizing the elongated styloid process itself as well as the relationship between the styloid process and surrounding soft tissue.

We report a case of central neurocytoma that manifested tumor recurrence with craniospinal dissemination. Imaging studies before surgery showed a markedly enhanced tumor with small cysts and calcification, which invaded the adjacent brain parenchyma, located in the posterior horn of the right lateral ventricle. Proton MR spectroscopy showed markedly elevated choline and lactate peaks with a strongly diminished N-acetylaspartate peak. Two years after neurosurgical intervention, the tumor showed multiple craniospinal dissemination in the middle cranial fossa and the intradural extramedullary space of the spine.