Improved breast cancer detection of prone breast fluorodeoxyglucose-PET in 118 patients.

OBJECTIVE: To prospectively evaluate the breast cancer detection of prone breast positron emission tomography (PET) images in comparison with supine whole-body PET images. MATERIAL AND METHODS: One hundred and eighteen female patients (age range 28-91 years) with 122 lesions suspected of having breast cancer underwent fluorine-18 fluorodeoxyglucose PET for preoperative staging. After the whole-body image was acquired, prone breast PET imaging was performed. The findings from both images were compared with the histopathologic results. Sensitivity, specificity, positive predictive value, negative predictive value (NPV), and accuracy were used to compare the diagnostic accuracy of prone breast PET images with that of whole-body PET images. RESULTS: Sensitivity, specificity, positive predictive value, NPV, and accuracy of whole-body PET images were 83, 50, 97, 17, and 80%, and of prone breast PET images they were 95, 50, 96, 43, and 93%. Ten of 114 breast cancerous lesions (8.8%) were detected on prone breast PET images alone. Statistical difference was found between the sensitivity, accuracy, and NPV of prone breast PET images and those of whole-body PET images (P<0.0001 for sensitivity and accuracy and P<0.0009 for NPV). CONCLUSION: Our data about the 122 lesions, suspected of breast cancer, with regard to the usefulness of prone breast PET imaging indicate that prone breast PET images are effective in detecting breast cancer.

[Development of automatic analysis for dynamic renal function study using computed tomographic (CT) images].

Determination of the region of interest (ROI) for dynamic renal function has been highly discordant among operators because of the dependence on factors such as the rate of injection of radioactive medicines, constitution, and renal function. To simplify this problem, we developed a computer algorithm that provides automatic analysis for both localization of the kidney and automatic determination of ROIs using computed tomographic (CT) images. The bilateral kidneys were extracted from enhanced CT images, and the CT pixel size was adjusted to dynamic renal function images. The template-matching technique was used for these images, and the kidney renal location was analyzed on additional functional images constructed by dynamic renal function images. As a result, we were able to obtain time-activity curves of both renal function and quantified glomerular filtration rate (GFR). In conclusion, the computer algorithm we developed was considered to provide reliable results, apart from the variability among operators, because of its good reproducibility.

[Research on time-course differential imaging by bone scintigraphy].

The temporal image subtraction technique was applied to bone scintigraphy, using Photoshop (commercially available image processing software) and Morpher (public domain warping software). For the temporal subtraction images, 81 subtraction images (19 cases) were prepared by a method used to subtract the previous images from the current ones. Registration of the current and previous images was performed by manual operation using Photoshop, and warping was done using the warping function of Morpher. In addition, difference images prepared after correcting the distributions of radioactive isotopes of the current and previous images using the count of the pelvic region were also examined. Compared with manual operation, alignment of images by warping improved registration and reduced the generation of pseudo-images of subtraction images. The rate of identification of abnormal accumulation-enhanced regions and subjective evaluation by doctors was improved for warping more than for manual operation. Furthermore, abnormal hot regions, which are difficult to find in film images, could be found in three subtraction images. In addition, it was confirmed that abnormal hot regions become more visible in many cases by preparing subtraction images after correcting the count between images using the count of the pelvic region. Thus, it is suggested that the temporal image subtraction technique in bone scintigraphy enables more accurate observation of enhancement of or changes in abnormal hot regions, which will support diagnostic reading. It is considered that enhancement of or changes in abnormal hot regions will be more accurately understood through further detailed discussion in the future.