Significance of distal fenestration in graft replacement for chronic aortic dissection.

It is recently controversial whether distal fenestration is necessary in graft replacement for chronic aortic dissection. Several groups started to try the exclusion of intimal entry by the insertion of a stent-graft as a treatment for chronic aortic dissection, while conventional surgical techniques consisted of graft replacement with distal anastomosis to both the true and false channels. It should be kept in mind that the resultant occlusion of the false lumen after obliteration of the false channel could promote spinal cord ischemia. We report a patient with delayed paraplegia after graft replacement without distal fenestration for chronic type B aortic dissection. It is possible that not all cases of chronic aortic dissection are good for stent-grafting.

Usefulness of magnetic resonance imaging for surgical management of extravasation of an antitumor agent: a case report.

We report a case of extravasation of an antitumor agent by preoperative magnetic resonance (MR) imaging. MR studies demonstrated a decreased signal intensity on T1- and T2-weighted images and a strong enhancement of contrast media in injured tissue, including subcutaneous adipose tissue and deep fascia, which was cicatrical macroscopically. The MR findings were in good agreement with the macroscopic findings. We believe that MR imaging is useful for estimating deep tissue damage due to extravasation of an antitumor agent.

Prenatal MRI in a fetus with a giant neck hemangioma: a case report.

We report a fetus with a giant neck hemangioma which was examined by MRI in utero. The initial diagnosis was made by ultrasonography. The sonolucent aspect of the mass, together with the presence of pulsating Doppler flow signals, was highly suggestive of a fetal hemangioma. In late pregnancy, fetal MRI revealed the location, size and characteristics of the neck tumor. Following prenatal corticosteroid treatment and premature delivery of the pregnancy due to fetal cardiac failure, the newborn received angiography and coil embolization of the tumor vessels. Despite vigorous treatments, the newborn died 12 h after birth. Evaluation of a fetal neck hemangioma by MRI is recommended late in pregnancy for precise information on the tumor and adjacent organs since the image is valuable for planning optimal perinatal treatment.

Use of fusion images of I-131 metaiodobenzylguanidine, SPECT, and magnetic resonance studies to identify a malignant pheochromocytoma.

Pheochromocytoma is a chromaffin tumor in which 10% are extra-adrenal and 10% are malignant. I-131 metaiodobenzylguanidine (MIBG) scintigraphy has an important role in the identification of these tumors and investigation of metastatic lesions. The authors describe a 36-year-old woman who underwent resection of a malignant left adrenal pheochromocytoma who was thought to have metastases in the liver and para-aortic lymph nodes. Fusion images of I-131 MIBG SPECT and magnetic resonance studies were obtained to properly identify the metastatic lesions. These fusion images helped greatly in subsequent surgery.

Microwave coagulation therapy: ex vivo comparison of MR imaging and histopathology.

We compared the findings of magnetic resonance (MR) images and pathological examination to determine whether or not MR images reflect pathological changes following microwave coagulation therapy (MCT) on liver tissue. We used microwave (generating frequency 2450 Mhz, wave length 12 cm, output 50 W, 60 second duration) to irradiate six canine livers under general anesthesia. After the animals were sacrificed, the livers were resected. The irradiated regions were cut with margins and divided into two pieces, one for MR study, and the other for pathological examination. The findings were compared. From the center to the marginal layer, the irradiated region presented 4/3 laminal patterns on T1/T2-weighted images: low/high, high/low, very high/high, and iso-low/high intensity. On gradient-echo imaging, the irradiated regions presented no decreasing signals using several echo time lengths. With hematoxylin and eosin stain, MR laminar patterns reflected the histopathological changes, as follows: a tissue loss area surrounding the inserted needle, low/high; decreased sinusoidal width with/without necrotic tissue, high/low; sinusoidal width dilation at the periphery, very high/high; and fatty degenerated tissue surrounding the irradiated area at the boundary of the normal hepatocytes, iso-low/high. The MR signal intensity, which reflected the histopathological changes, presented tissue characterization after MCT, and the macromolecular hydration effect influenced the high intensity on T1-weighted images.

Microwave coagulation therapy on hepatomas: CT and MR appearance after therapy.

Laparoscopic microwave coagulation (LMC) for hepatocellular carcinomas (HCCs) was performed on 26 HCCs in 17 patients. Contrast-enhanced CT (CECT) and MR images (T1-weighted imaging [T1WI], T2WI, gadolinium-diethylenetriamine pentaacetic acid [Gd-DTPA] T1WI) were obtained to determine changes over time. The irradiated center exhibited low to moderate intensity with surrounded high intensity (HI) on T2WI and Gd-DTPA T1WI. On T1WI, lesions showed four patterns of intensity: uniform HI (30.8%), arcuate HI (26.9%), mainly low with spot HI (30.8%), and isointensity to hypointensity (11.5%). Follow-up imaging at more than 170 days revealed isointensity to hypointensity on T1WI (96.2%) and reduced HI on T2-weighted imaging (T2WI) and Gd-DTPA T1WI. All lesions became less conspicuous and were reduced in volume. HCC shows time-related changes in signals and size after LMC. Identifying the irradiated lesion is necessary to estimate the adequacy of treatment by comparison with the pretherapeutic image.

[Accelerated hyperfractionation in the treatment of malignant glioma].

A retrospective evaluation was performed to determine whether accelerated hyperfractionation (AHF) improves the survival rate of patients with malignant gliomas. One hundred and seven patients with malignant gliomas, including glioblastoma multiforme, who had received radical radiotherapy were evaluated. Of the patients, 36 were treated by conventional fractionation (CF), and 71 by AHF. The treatment results of the two regimens were compared with regard to survival rate after therapy. Treatment by AHF was conducted at 10-15 F/W (1.5 Gy/F); the mean total dose was 61 Gy over an average of 27 days. Treatment by CF was conducted at 5 F/week (1.8-2 Gy/F); the mean total dose was 59 Gy over 51 days. Multivariate analysis using Cox's proportional hazard model revealed that AHF significantly increased survival rate. Besides pointing to the selection of the AHF method as a treatment regimen, multivariate analysis showed the following factors to be indicators of favorable prognosis: a histopathological diagnosis other than glioblastoma multiforme, age below 40 years, and supratentorial location of the tumor.