Radiation medicine最新文献

Purpose: The aim of this study was to develop an automated method of segmenting the cerebrum, cerebellum-brain stem, and temporal lobe simultaneously on magnetic resonance (MR) images.

Methods and materials: We obtained T1-weighted MR images from 10 normal subjects and 19 patients with brain atrophy. To perform automated volumetry from MR images, we performed the following three steps: (1) segmentation of the brain region; (2) separation between the cerebrum and the cerebellum-brain stem; and (3) segmentation of the temporal lobe. Evaluation was based on the correctly recognized region (CRR) (i.e., the region recognized by both the automated and manual methods).

Results: The mean CRRs of the normal and atrophic brains were 98.2% and 97.9% for the cerebrum, 87.9% and 88.5% for the cerebellum-brain stem, and 76.9% and 85.8% for the temporal lobe, respectively.

Conclusion: We introduce an automated volumetric method for the cerebrum, cerebellum-brain stem, and temporal lobe on brain MR images. Our method can be applied to not only the normal brain but also the atrophic brain.

Optimal management of radiotherapy for prostate cancer patients has become a major concern for physicians in Japan. We reviewed published reports identifying the differences in the patterns of care for prostate cancer patients treated with radical external beam radiotherapy in Japan, Germany, and the United States. The reports indicate that Japanese patients have more advanced primary disease than patients in Germany or the United States. These patient characteristics for Japan and the United States have been almost unchanged for several years. Regarding radiotherapy, conformal radiotherapy was less frequently administered to patients in Japan than patients in Germany or the United States, and the total radiation dose was higher in Germany and the United States than in Japan. Concerning changes in trends in the patterns of radiotherapy, the percentage of patients treated with higher dose levels in the United States has rapidly increased, whereas the percentage of patients receiving these dose levels in Japan has remained extremely low. On the other hand, hormonal therapy has been used more frequently in Japan than in Germany or the United States. These findings indicate that patient characteristics and patterns of care for prostate cancer in Japan are considerably different from those in Germany or the United States.

Computed tomography findings of pathologically proven pulmonary infarction associated with bronchogenic carcinoma are reported for two patients. In one case, the infarction was demonstrated as a well-defined pleura-based large nodule in the peripheral portion of the same lobe of the tumor. The nodule had a smooth, convex border and a linear strand from the apex of the lesion toward the hilum. The obstruction of the subsegmental pulmonary artery due to tumor invasion was considered the cause of pulmonary infarction. In the second case, the infarction was demonstrated as a rapidly appeared, pleura-based consolidation in the same lobe of the tumor with a blurred border. Obstruction of the pulmonary vein by a tumor might have played an important role in the development of the pulmonary infarction in association with a large pulmonary artery obstruction. We conclude that pulmonary infarction should be considered as a differential diagnosis when peripheral pulmonary nodules or masses are located in the same lobe as the primary cancer.

Purpose: The aim of this study was to clarify the usefulness of the isocenter puncture (ISOP) method.

Materials and methods: We investigated 73 vertebral bodies that had undergone percutaneous vertebroplasty (PVP) by the ISOP method, 118 vertebral bodies that had undergone the puncture simulation method, and 33 vertebral bodies that had undergone the conventional method. The items to be examined included the success rate (SR) of the median puncture of the vertebral body and the procedure time. The puncture accuracy and fluoroscopy time were also measured for the ISOP method.

Results: The SR was significantly higher and the procedure time significantly shorter when using the ISOP method rather than the conventional method. However, no significant differences were observed between the ISOP method and the puncture simulation method. The errors between the puncture needle tip and the puncture target point in the ISOP method were an average of 1.52, 2.08, and 1.87 mm in each of the horizontal, ventrodorsal, and craniocaudal directions. The fluoroscopy time when operating on one vertebral body was an average of 5.8 min.

Conclusion: The ISOP method is considered to be a useful approach while also reducing the puncture time and the fluoroscopy time.

We present an adult patient with a massive mucinous cystadenoma of the appendix that induced intussusception. Multiplanar reconstruction images and maximum intensity projection images enabled us to assess the tumor accurately and characterize the intussusception. Thus, reconstructed computed tomographic images proved highly useful for diagnosis.

Purpose: The aim of this retrospective analysis was to evaluate the accuracy of 10 mm thickness single helical computed tomography (CT) examination for confirming the diagnosis of appendicitis or providing a diagnosis other than appendicitis, including underlying periappendical neoplasms.

Materials and methods: From April 1, 2001 to March 30, 2005, a total of 272 patients with suspected appendicitis underwent CT examinations. Of the 272 patients, 106 (39%) underwent surgery. Seven CT examinations for seven patients were excluded because of inconsistency of the CT protocol. We therefore reviewed 99 CT images (99 patients) with correlation to surgical-pathological findings to clarify the diagnostic accuracy of CT examinations. We compared the postoperative diagnosis with the preoperative CT report. The final diagnoses were confirmed by macroscopic findings at surgery and pathological evaluations if necessary.

Results: Of the 99 patients, 87 had acute appendicitis at surgery. The sensitivity, specificity, and accuracy of CT were 98.9%, 75.0%, and 96.0%, respectively. The positive predictive value and negative predictive value were 96.6% and 90.0%, respectively. Among nine patients in the true-negative category, five had colon cancers; and among three patients in the false-positive category, two had cancer of the cecal-appendiceal region as the underlying disease.

Conclusion: CT examination is useful for patients with suspected appendicitis, but radiologists should be aware of the limitation of thick-sliced single helical CT. They should also be aware of the possibility of other diseases, including coincident abdominal neoplasms and underlying cecal-appendiceal cancer.

Painful splenomegaly has a clinical presentation that is often associated with myeloproliferative disorders, such as acute or chronic lymphoblastic or myelogenous leukemia. In these situations low-dose radiotherapy is effective in reducing the splenomegaly and relieving pain. The potential benefit of radiotherapy for cardiogenic splenomegaly is less well established. The present report discusses a case in which radiotherapy was employed to benefit a patient with Eisenmenger's-associated painful splenomegaly. Because of the patient's high anesthesia risk, palliative surgical splenectomy was not feasible. The patient underwent three-dimensional conformal treatment planning, and a total of 42.5 Gy at 2.5 Gy per fraction was prescribed to the spleen. At 4 months following radiotherapy completion, the patient reported durable pain relief and no untoward small bowel effects; moreover, there was a 43% reduction in splenic volume on follow-up CT. Although there have been previous reports of hematological and myeloproliferative-associated splenomegaly that have been treated with a lower dose per fraction and lower total dose radiotherapy, we advocate the use of 2.0-2.5 Gy per fraction to a total dose approaching 40 Gy for adequate duration of response when treating cardiogenic-associated painful splenomegaly in patients for whom surgical splenectomy cannot be performed.

Prostatic abscess involving the seminal vesicle has become rare following the development of effective antibiotic treatments. To our knowledge, we report the first case in the English-language literature of a patient with a spermatic cord abscess and a concurrent prostatic abscess. We examined an 81-year-old man for swelling and pain in the left inguinal region and performed computed tomography (CT) that later confirmed the suspected diagnosis of left inguinal hernial strangulation. We performed urgent surgical drainage of a left spermatic cord abscess; and under the correct diagnosis by CT, he was successfully treated further with antibiotics and transperineal drainage of a prostatic abscess extending to the seminal vesicle. We highlight that familiarity with such a rare condition is overwhelmingly essential for patient management and that CT is the most valuable imaging procedure for diagnosing such cases.

Purpose: The aim of this study was to present the technical aspects of the breath-hold technique with respiratory monitoring and visual feedback and to evaluate the feasibility of this system in healthy volunteers.

Methods and materials: To monitor respiration, the vertical position of the fiducial marker placed on the patient's abdomen was tracked by a machine vision system with a charge-coupled device camera. A monocular head-mounted display was used to provide the patient with visual feedback about the breathing trace. Five healthy male volunteers were enrolled in this study. They held their breath at the end-inspiration and the end-expiration phases. They performed five repetitions of the same type of 15-s breath-holds with and without a head-mounted display, respectively. A standard deviation of five mean positions of the fiducial marker during a 15-s breath-hold in each breath-hold type was used as the reproducibility value of breath-hold.

Results: All five volunteers well tolerated the breath-hold maneuver. For the inspiration breath-hold, the standard deviations with and without visual feedback were 1.74 mm and 0.84 mm, respectively (P = 0.20). For the expiration breath-hold, the standard deviations with and without visual feedback were 0.63 mm and 0.96 mm, respectively (P = 0.025).

Conclusion: Our newly developed system might help the patient achieve improved breath-hold reproducibility.

The cerebrovascular complications of Takayasu arteritis are primarily related to the presence of occlusive lesions. Cerebral aneurysms rarely occur as complications; only 18 cases have been reported thus far. The use of coil embolization to treat cerebral aneurysms occurring as a complication of Takayasu arteritis has not been previously reported. We report a case of Takayasu arteritis with a basilar tip aneurysm and a P1 segment aneurysm of the left posterior cerebral artery that were successfully treated with coil embolization. Because coil embolization for cerebral aneurysms associated with Takayasu arteritis requires the use of limited access routes that have extremely curved and tortuous courses, catheter navigation was difficult. The guide catheter, microcatheter, and guidewire must be selected and navigated with greater care than is usually required for common aneurysm embolization.