Radiation medicine最新文献

Purpose: The aim of this study was to assess the feasibility and effectiveness of magnetic resonance (MRI)-guided focused ultrasound (MRIgFUS) ablation for uterine fibroids and to identify the candidates for this treatment.

Materials and methods: A total of 48 patients with a symptomatic uterine fibroid underwent MRIgFUS. The percent ablation volume was calculated, and the patients' characteristics and the MR imaging features of the fibroids that might predict the effect of this treatment were assessed. Changes in the symptoms related to the uterine fibroid were assessed at 6 and 12 months.

Results: The planned target zone were successfully treated in 32 patients with bulk-related and menstrual symptoms but unsuccessfully treated in the remaining 16 patients. These 16 patients were obese or their uterine fibroid showed heterogeneous high signal intensity on T2-weighted images. The 32 successfully treated patients were followed up for 6 months. At the 6-month follow-up, bulk-related and menstrual symptoms were diminished in 60% and 51% of patients, respectively. Among them, 17 patients were followed up for 12 months, and 9 of them who showed alleviation of bulk-related symptoms at 6 months had further improvement. The mean percent ablation volume of those nine patients was 51%. In 5 (33%) of the 15 patients with alleviation of menstrual symptoms at 6 months, the symptoms became worse at 12 months. There was a significant difference in the mean percent ablation volume between patients with alleviation of menstrual symptoms and those without (54% vs. 37%; P = 0.03).

Conclusion: MRIgFUS ablation is a safe, effective treatment for nonobese patients with symptomatic fibroids that show low signal intensity on T2-weighted images. Ablation of more than 50% of the fibroid volume may be needed with a short-term follow-up.

Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor that commonly arises in the lower extremities but rarely in the mesentery. We report computed tomography (CT) and magnetic resonance imaging (MRI) findings of LGFMS of the small bowel mesentery. On CT, the mass was composed of two components. One component, on its right side, appeared to have isointense attenuation relative to muscle, whereas the other component, on its left side, appeared to have low attenuation. On MRI the mass on the right side showed hypointensity similar to muscle on both T1-and T2-weighted images as well as mostly slight enhancement on contrast-enhanced T1-weighted images. On the other hand, the mass on the left side showed relative hypointensity on T1-weighted images and hyperintensity on T2-weighted images as well as intense enhancement on contrast-enhanced T1-weighted images, suggesting that the tumor contained myxoid tissue. The myxoid area of LGFMS may have a tendency to reveal intense enhancement on contrast-enhanced images.

Purpose: The aim of this study was to assess the incidence, degree, and predictors of hepatic arterial damage (HAD) after transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC).

Materials and methods: A total of 33 patients with unresectable HCC underwent TACE alone using a mixture of iodized oil, epirubicin, and gelatin sponge. A follow-up angiogram was available for 76 of 109 sessions, and HAD was evaluated at each subsegment of the hepatic artery using a three-grade scale (1, no or slight wall irregularity; 2, overt stenosis; 3, occlusion). Grades 2 and 3 were considered to indicate significant HAD. The predictors of HAD were analyzed by multivariate analysis.

Results: A total of 161 hepatic arteries were embolized from the lobar (n = 43), segmental (n = 40), subsegmental (n = 72), or more distal (n = 6) level. The follow-up period between the initial and last sessions ranged from 70 to 1505 days (median 497 days). Significant HAD occurred in 37 of 231 subsegmental hepatic arteries (16%) and in 16 of 33 patients (48%). The accumulated dose of epirubicin per artery (P = 0.001) and Child-Pugh score (P < 0.001) were significant predictors.

Conclusion: TACE is more likely to induce HAD in cirrhotic patients with impaired liver function and when a high dose of the chemotherapeutic agent was used.

Purpose: The purpose of this study was to examine the relation between cancer cellularity and the apparent diffusion coefficient (ADC) value using diffusion-weighted magnetic resonance imaging in breast cancer.

Materials and methods: The subjects were 27 women who had undergone operation for breast cancer. There were 27 breast cancer lesions, 24 of which were invasive ductal carcinoma (IDC) and 3 of which were noninvasive ductal carcinoma (NIDC).

Results: The mean ADC values of IDC, NIDC, and normal breasts were 1.07 +/- 0.19 .10(-3), 1.42 +/- 0.17 .10(-3), and 1.96 +/- 0.21 .10(-3) mm(2)/s, respectively. The mean ADC values of IDC and NIDC were significantly different from that of normal breasts (P < 0.001 each). The mean ADC values were also significantly different between IDC and NIDC (P < 0.001). There was no correlation between the ADC value and cancer cellularity.

Conclusion: The mean ADC values for breast cancer were significantly different from that of normal breasts. The mean ADC value for breast cancer did not significantly correlate with cancer cellularity but did correlate with histological types.

Purpose: The aim of this study was to validate the use of a calibration factor measured outside the object for estimating the iodine concentration inside the object to improve the accuracy of the quantitative contrast-enhanced computed tomography (CT).

Materials and methods: Several known concentrations (0, 6, 9, and 12 mg I/ml) of iodine contrast material (CM) samples were placed inside and outside cylindrical acrylic phantoms of two sizes and were imaged under various combinations of the tube voltages and currents (kV/mAs-80/200, 100/200, 120/200, 140/200) to obtain K factors. The K factors were compared between the phantoms and among the tube voltages. Each CM concentration was estimated from the CT number using the K factor measured outside the phantom.

Results: The K factors varied between the phantoms or among the tube voltages (P < 0.05). Although there were statistically significant variations in K factors among the different regions in a phantom, the mean variation coefficient was 3%-4%. The mean error of the estimated concentration was -5.5%.

Conclusion: The CM concentration should be accurately estimated at the region within a patient's body using the K factor measured at the surface of the body regardless of body size and tube voltage.

Two women presented with sore throat and fever. Their symptoms were not alleviated by antibiotics. Cervical computed tomography (CT) with contrast enhancement demonstrated enlargement of predominant posterior cervical lymph nodes and streaky heterogeneous tonsils with interspersed low attenuation. They were diagnosed as having infectious mononucleosis by their laboratory data. Thus, when radiologists encounter these CT findings of pharyngitis that is not alleviated by antibiotic therapy, infectious mononucleosis should be considered in the differential diagnosis.

Purpose: The aim of this study was to evaluate the indications, efficacy, and safety of arterial catheterization and embolization for the management of emergent or anticipated massive obstetrical hemorrhage and its effects on menses and fertility.

Materials and methods: Eighteen patients underwent arterial catheterization and embolization for intractable obstetrical hemorrhage between January 2001 and December 2005. Three groups of patients were identified: group 1 (n = 6) experienced postpartum hemorrhage; group 2 (n = 5) had anticipated severe postpartum hemorrhage; and group 3 (n = 7) had a risk factor for anticipated severe hemorrhage after dilation and evacuation. Gynecological information after embolization was obtained from medical records and telephone interviews.

Results: All patients in group 1 had a favorable outcome after treatment with a single embolization. All patients in group 2 had a placenta previa with an estimated blood loss of 1215-3250 ml. In group 3, bleeding was controlled in six patients; one patient had a hysterectomy because embolization was not possible. There were no short-or long - term complications, and normal menstruation resumed. Four patients became pregnant after embolization.

Conclusion: Arterial catheterization and embolization is an effective, safe method for treating intractable obstetrical hemorrhage and might eliminate the need for hysterectomy and maintain reproductive ability.

Purpose: This study was aimed to validate the performance of a novel image compression method using a neural network to achieve a lossless compression. The encoding consists of the following blocks: a prediction block; a residual data calculation block; a transformation and quantization block; an organization and modification block; and an entropy encoding block. The predicted image is divided into four macro-blocks using the original image for teaching; and then redivided into sixteen sub-blocks. The predicted image is compared to the original image to create the residual image. The spatial and frequency data of the residual image are compared and transformed.

Materials and methods: Chest radiography, computed tomography (CT), magnetic resonance imaging, positron emission tomography, radioisotope mammography, ultrasonography, and digital subtraction angiography images were compressed using the AIC lossless compression method; and the compression rates were calculated.

Results: The compression rates were around 15:1 for chest radiography and mammography, 12:1 for CT, and around 6:1 for other images. This method thus enables greater lossless compression than the conventional methods.

Conclusion: This novel method should improve the efficiency of handling of the increasing volume of medical imaging data.

Purpose: KL-6 is an extracellular epitope of MUC1, a membrane-penetrating glycoprotein, and its overexpression has been reported in pancreatic cancer. The aim of this study was to examine whether radiolabeled anti-KL-6/MUC1 antibody could be used for molecular imaging of pancreatic cancer in vivo.

Materials and methods: Anti-KL-6/MUC1 antibody was labeled with 99mTC by the stannous reduction method. Immunoreactivity of the 99mTc-labeled anti-KL-6/MUC1 antibody was evaluated by a whole-cell binding study. In vivo experiments were performed by injecting the 99mTc-labeled anti-KL-6/MUC1 antibody into athymic nude mice bearing the KP-1NL pancreatic cancer cell line.

Results: A whole-cell binding study showed that the radiolabeled antibody retained its immunoreactivity. On scintigrams, the density of the tumors remained unchanged during the 16-32 h after injection, whereas that of the kidneys decreased time-dependently. The radioactivity levels of the kidneys and tumors were measured densitometrically, and we found that the intensity in the tumors relative to that in the kidneys increased time-dependently. Radioactivity levels were the highest in the blood 32 h after injection, and those in the liver, kidney, lung, and tumor were also rather high.

Conclusion: 99mTc-labeled anti-KL-6/MUC1 antibody appears to be a promising agent as a tumor-specific radiotracer for pancreatic cancer.

Purpose: The aim of this study was to evaluate retrospectively the toxicity and response, bladder preservation, and survival of patients with muscle-invasive bladder cancer treated with multimodality therapy consisting of low-dose radiation therapy (RT) and concurrent intraarterial chemotherapy (IACT).

Methods and materials: . Between November 1999 and July 2005, a total of 27 consecutive, previously untreated patients with muscle-invasive bladder cancer underwent transurethral bladder tumor resection followed by concurrent low-dose RT and IACT. Patients who achieved a complete response (CR) were followed up closely without further therapy, and patients who did not achieve a CR underwent further treatment.

Results: Complete response was achieved in 22 of 27 patients (81%). Of these 22 patients, 7 developed recurrences, and 3 died of their disease. In five patients who did not achieve CR, one died from bone metastases. The 3-year overall survival rate was 81%, with a median follow-up time of 27 months; and 22 of 27 patients (81%) with a preserved bladder were tumor-free at the last follow-up. Three patients (11%) developed grade 3 acute hematological toxicity.

Conclusion: Multimodality therapy consisting of low-dose RT and concurrent IACT for muscle-invasive bladder cancer can achieve survival rates similar to those in patients treated with radical cystectomy, with successful bladder preservation and minimal adverse effects.