Nihon Igaku Hoshasen Gakkai zasshi. Nippon acta radiologica最新文献

Purpose: To compare dual-phase contrast-enhanced multidetector-row CT (MDCT) with high-spatial-resolution MRI using a three-dimensional volumetric interpolated breath-hold examination (VIBE) sequence for evaluation of the extent of ductal carcinoma in situ (DCIS).

Materials and methods: A retrospective review was conducted in 17 consecutive patients with DCIS in which both MDCT and MRI had been performed. The early phase of MDCT and MRI was started 60 sec after commencing contrast injection. The late phase was started 4 min after the injection. The size of the lesion on MDCT and MRI was measured in coronal images obtained during the early and late phases. Histological evaluation of the size was considered the gold standard, and the deviation in tumor size as measured in the early- and late-phase images from the histologically determined tumor size was calculated.

Results: The sensitivity rates of MDCT and MRI for the detection of DCIS were 88.2% (15/17)and 100%, respectively, and no lesions were detected in the late-phase images alone. The accuracy of detection of tumor diameters with a deviation of less than 2 cm was 76.5% (13/17) with MDCT and 94.1% (16/17) with MRI. The tumor diameter was overestimated by more than 2 cm in 2 lesions (11.8%) on MDCT and one lesion (5.9%)on MRI, in both early- and late-phase scans. Tumor diameter was underestimated in early- as compared to late-phase scans in 3 cases on MDCT and one case on MRI.

Conclusion: High-spatial-resolution MRI using the VIBE sequence is more accurate for the detection and evaluation of the extent of DCIS than MDCT. In dynamic studies, more accurate evaluation of the extent of DCIS is possible in late-phase images.

With the increasing demand on picture archiving and communication systems (PACS) to handle larger numbers of images, much research has been conducted on the utilization of lossy compression for efficient communication and storage in PACS systems. The receiver operating characteristics (ROC) method is commonly used to determine the appropriate compression ratio of lossy images. However, conducting an ROC experiment is impractical at actual medical facilities because it is difficult to prepare and interpret images with different compression ratios for each modality, body part, and acquisition method. On the other hand, experienced radiologists have the ability to subjectively assess the level of image quality required for interpretatior and quantitative analysis. Therefore, by simply viewing images, they are able to determine the appropriate criteria for image quality and derive a practical compression ratio for each application. The present study focused on lossy compression as employed in teleradiology systems for medical checkups. Experiments comparing radiologists' subjective assessment of compressed images against the diagnostic results obtained using these images were conducted in order to investigate appropriate compression ratios and efficient methods for determining them.

Uterine artery embolization using gelatin sponge particles was performed in a miniature pig, and the distribution of the particles was investigated. The particles spread in the cervix and proximal portion of the left horn. Histological study revealed embolic material in both the myometrium and endometrium. Several particles were found even in arteries smaller than 100 microm in diameter in the endometrium. Further studies should address the risks of gelatin sponge particles in the peripheral arteries of the uterine endometrium, as they may induce inflammatory processes and evoke complications including infection and menopause.

A 42-year-old woman with bilateral massive ovarian edema (MOE) is presented. MOE is usually seen in women 6 to 33 years of age. Therefore, accurate re-operative assessment of MOE is important to avoid unnecessary oophorectomy procedures. MR findings of MOE are characteristic and reflect very well the diffuse stromal edema noted on microscopy. The etiology and MR findings of MOE are discussed.

Purpose: The clinical experiences of 12 patients with non-hepatic abdominal tumors who underwent stereotactic hypofractionated radiotherapy are presented.

Methods and materials: Ten lesions were metastatic, one was a primary pancreatic cancer, and the remaining one was irradiated postoperatively for a positive margin of extrahepatic bile duct cancer. In one patient, single fractional stereotactic radiotherapy was employed, while the remaining 11 patients were treated with 3 fractions. Gross tumor volume of the 10 ranged from 2 cc to 32 cc (mean: 11 cc), and the minimal dose enclosing 95% of the planning target volume (D95) was between 28.6 Gy and 35 Gy. The minimal number of portals was 6. In 8 patients, radiotherapy was performed under respiratory gating. Mean follow-up time was 10 months (5-51 months).

Results: Local regrowth was seen in 9 months in only 1 of the 12 tumors, and the patient died of the disease. Four patients died because of tumor growth in other sites. The remaining 7 patients are alive without disease. As for morbidity, NCI-CTC grade 3 gastritis was seen in one patient, grade 2 gastritis in 2 patients, and grade 2 duodenitis in one patient. These patients all improved with non-surgical therapy.

Conclusion: Stereotactic hypofractionated radiotherapy is effective for the treatment of selected non-hepatic abdominal tumors. However, the optimal radiation dose for tumor control and the tolerance dose of the gastrointestinal tract in hypofractionated irradiation must be studied further.

Purpose: To study the frequency of visualization and characteristics of normal thoracic structures on lateral chest radiographs in the Japanese population.

Materials and methods: We reviewed 316 lateral chest radiographs of men and women ranging in age from 20 to 90 years. The frequency of visualization and configuration of structures including major, minor, superior and inferior accessory fissures, and orifices of the right and left upper lobe bronchi were reviewed.

Results: On lateral chest radiographs, major fissure and minor fissure were visualized in 99.4% and 87.3%, respectively. Superior accessory fissure and inferior accessory fissure were visualized in 1.9% and 9.5%, respectively. Orifices of the right and left upper bronchi were seen in 92.4% and 98.4%, respectively.

Conclusion: Frequency of visualization and characteristics of various normal anatomic structures on lateral chest radiographs in the Japanese population differ from those reported previously from the West. Familiarity with these normal thoracic structures and variations is important for daily image interpretation.

Medical accidents recently have become a social problem as a result of the old-fashioned hospital system in Japan. Therefore, risk management for medical procedures has been considered very important. In the field of radiotherapy, specific characteristics include the management of radiation and the triangular relationship between patients, referred doctors, and radiation oncologists. In future, the difference between incident and accident in radiotherapy should be clearly defined by the Society.

Purpose: To compare rates of accuracy of recognition between experienced dictators and inexperienced ones in using an enrollment-less continuous speech recognition (CSR) system of radiological reporting, and to evaluate the usefulness of the system.

Materials and methods: Twenty board-certified radiologists were classified into 2 groups: a group of 10 members with more than 6 years' experience of conventional dictation by transcriptionist (group A) and a group of 10 members with no experience of dictation (group B). All radiologists created fresh radiological reports on sets of images using free-style dictation in the reports. We counted errors and total words in the reports individually, and compared the rates of accuracy of word recognition in the two groups. We used a CSR system AmiVoice (Advanced Media, Inc., Tokyo, Japan).

Results: The average rate of accuracy of word recognition was 96.42 +/- 1.68% in group A and 95.92 +/- 1.15% in group B. There was no significant difference in accuracy rate between the two groups.

Conclusion: The accuracy of word recognition was independent of the experience of dictation, and the enrollment-less CSR system of radiological reporting was considered convenient and useful.

B-flow imaging is a recently developed ultrasound technique that extends the B-mode imaging quality of blood flow, including high-frame-rate and high-spatial-resolution imaging. The purpose of the present study was to clarify the usefulness of B-flow for evaluation of the hemodynamics of superficial soft tissue tumors. All 33 cases of superficial soft tissue tumors were examined by both B-flow and Color/Power Doppler methods on the same plane. The B-flow images that were obtained were evaluated by comparison with corresponding Color/Power Doppler images. The following four items were compared and evaluated: (1) sensitivity to the detection of tumor vessels; (2) quality of background B-mode imaging; (3) frame rate; and (4) spatial resolution of tumor vessels. B-flow was somewhat inferior to Color/Power Doppler imaging in sensitivity to the detection of tumor vessels. B-flow was clearly inferior in the quality of background B-mode imaging. B-flow provided high-frame-rate imaging. The diameter of tumor vessels on B-flow imaging was clearly thinner than that on Color/Power Doppler images and appeared to indicate the true diameter of tumor vessels. By providing high-frame-rate imaging and high spatial resolution, B-flow makes it possible to clarify the precise vascular structure.

Purpose: We report here our experience of brachytherapy using I-125 seeds for localized prostate cancer in 100 patients.

Materials and methods: We carried out brachytherapy with I-125 seed permanent implants in 100 patients with localized prostate cancer between September 2003 and October 2004. Preplanning dosimetry was done using transrectal ultrasonic images obtained three or four weeks prior to treatment. Using transrectal ultrasound, we inserted I-125 seeds in the prostate through needles according to the preplanning diagram. We then examined the results on prostate CT performed one month later.

Results: It was necessary to describe transrectal ultrasonic image such as preplanning. There were several cases in which the source arrangement of the schedule was corrected immediately before the operation. In the examination after one month, the numerical value at the start of treatment initially was not satisfactory, but we eventually obtained a result that could to be evaluated.

Conclusion: We carried out permanent implant brachytherapy for localized prostate cancer using I-125 seeds and reported our experience.