Faculty Bibliography

Fusing or image registration improves the information obtained by correlating images from various imaging modalities. We 'fused' radiolabeled antibody SPECT with CT in patients with colorectal or lung cancer. We identified corresponding landmarks on cross-sectional images and used standard graphics algorithms for untilting to match planes of reconstruction and for two-dimensional warping or transformation of images or regions of interest. Fusing localizes activity on SPECT to specific anatomic structures and decreases SPECT false positives and CT false negatives

Thirty-seven patients with 69 suspected hemangiomas found by means of computed tomography (CT) and/or ultrasound were studied with both 0.5-T magnetic resonance (MR) imaging and single photon emission CT (SPECT) with technetium-99m-labeled red blood cells. Using a criterion of 'perfusion-blood pool mismatch,' SPECT readers diagnosed 50 of 64 hemangiomas and all five 'nonhemangiomas' (sensitivity, 78% [95% confidence interval, 0.664 - 0.864]; accuracy, 80% [0.69 - 0.877]). Qualitative analysis of lesion signal intensity on T2-weighted spin-echo MR images allowed readers to diagnose 58 of 64 hemangiomas and four of five nonhemangiomas (sensitivity, 91% [0.814 - 0.96]; accuracy, 90% [0.807 - 0.951]). Because of the significantly higher cost of MR imaging and its inability to categorically differentiate hemangiomas from hypervascular metastases, the authors consider SPECT to be the method of choice for diagnosing hepatic hemangiomas. MR imaging should be reserved for the diagnosis of lesions smaller than 2.0 cm and for those 2.5 cm and smaller adjacent to the heart or major hepatic vessels; in such cases MR imaging was found superior to SPECT

The authors describe some of the advantages of surface extraction and imaging over solid three-dimensional volume imaging for certain applications in medicine and biology. It is pointed out that, in many clinical fields (e.g., craniofacial surgery), the subject of interest is the surface of only one type of body tissue. Volume images of the overlying soft tissue merely obscure the subject. Further, in surgical simulation programs used in these disciplines, interactivity is of paramount importance. The relative simplicity of the surface image makes real-time image generation more tractable. Surface normal calculations may be combined with a good lighting model for extremely realistic images. Surface extractions are a requirement for statistical comparisons of volume images with a normative data set

To enhance the information provided by computed tomography (CT) and single photon emission computed tomography (SPECT) performed with radiolabeled, anti-carcinoembryonic antigen monoclonal antibody (MoAb), the authors performed fusion of these types of images from eight subjects with suspected colorectal adenocarcinoma. Section thickness and pixel size of the two studies were matched, coordinates of corresponding points from each study were identified, and CT sections were translated, rotated, and reprojected to match the corresponding SPECT scans. The CT-SPECT fusion enabled identification of anatomic sites of tumor-specific MoAb accumulation in four cases, showed non-specific MoAb accumulation in two, and helped confirm information only suggested by the two studies separately in one

The publication of AAPM Report No. 10 was the first attempt to standardize image formats in the medical imaging community. Since then, three other groups have formed (CART--the Scandinavian collaboration for Computer Assisted Radiation Therapy treatment planning; ACR-NEMA, a collaboration whose purpose is to formulate a standard digital interface to medical imaging equipment; and COST B2 Nuclear Medicine Project a European collaboration whose purpose is to define a format for digital image exchange in Nuclear Medicine). The AAPM format uses key-value pairs in plain text to keep track of all information associated with a particular image. The radiation oncology community in the U.S. has been defining key-value pairs for use with CT, nuclear medicine and magnetic resonance (MR) images. The COST B2 Nuclear Medicine Project has also adopted this format and together with the Australian/New Zealand Society of Nuclear Medicine Technical Standards Sub-Committee which has also adopted this format, has defined an initial set of key-value pairs for Nuclear Medicine images. Additionally, both ACR-NEMA and CART have been defining fields for use with the same types of images. The CART collaboration has introduced a database which is available electronically, but is maintained by a group of individuals. ACR-NEMA operates through committee meetings. The COST B2 Nuclear Medicine Project operates through electronic (and postal where necessary) mail. To insure a consistent set of field names in such a rapidly developing arena requires the use of a server rather than a committee. Via a server a person would inquire if a particular field had been defined. If so, the defined name would be returned.(ABSTRACT TRUNCATED AT 250 WORDS)