Current Medical Imaging - Volume 5, Issue 4, 2009

This issue again presents advanced imaging techniques to assess clinical problems related to myocardial perfusion, breast cancer, soft tissue sarcoma, intraarterial chemotherapy, diseases in craniocervical junction, and oral and maxillofacial diseases. There are also paper analyzing calcium phosphate urinary stone on abdominal X-ray and special article reporting research and development of nuclear molecular imaging in Taiwan. The pathogenesis and clinical significance of reverse redistribution on myocardial perfusion scan have remained unclear and controversial, and thus perplexed nuclear physicians as well as cardiologists in clinical practice. He and Yang reviewed the spectrum of the reverse redistribution in different entities with various radiotracers. They have focused on clinical significance and strategies as well as underlying mechanism of reverse redistribution in coronary atery diseases. FDG PET/CT has been recognized as a useful technique for staging various cancers. However, its role in staging breast cancer has been subject to discussions, probably related to relatively low metabolic activity of the breast cancer. Aukema et al. reviewed the current literature of methological and clinical value of FDG PET/CT in staging and restaging breast cancer. Sonography has not been generally accepted as an imaging modality for the evaluation of soft tissue sarcomas which are anatomically and histologically diverse tumors. Kneif et al. report three dimensional ultrasonography (3D US) to display tumors in spatially oriented and standardized views. Improved visualization and guidance of interventional procedures using 3D US may increase the acceptance of clinicians to utilize ultrasonography for the evaluation of soft tissue tumors. Intraarterial infusion chemotherapy has the advantage of delivering relatively high dose of chemotherapy drugs into tumor bed with fewer systemic side effects. 3D CT angiography has been used to assess the arterial anatomy, but it is often affected by dental metallic artifacts. Tsutsumi et al. report the utility of 3D intravenous digital subtraction angiography studies in 15 patients that were able to depict the external carotid artery without any significant problem. The preoperative precise evaluation of disease process and its relationship with adjacent tissues in the craniocervical junction is very important for the proper treatment plan. Kiresi and Kadiyoran discuss the role of multidetector CT with pictorial reviews of various pathologies in the craniocervical junction. Various imaging modalities are available for the diagnosis of diseases affecting oral and maxillofacial areas with complex anatomy. Morimoto et al. rescribe the significance and clinical application of each modality in the evaluation of oral and maxillofacial diseases. Calcium phosphate urinary stones do not have specific features on abdominal X-ray, and thus they are often misclassified. Tokgoz et al. analyzed cases of pure calcium phosphate renal or ureteral stones in 60 patients and categorized in 4 groups. Shen et al. report their research and development of nuclear molecular imaging in Taiwan with the radiopharmaceuticals for imaging central nervous system disorders and cancer imaging, targeting specific cancers as well as establishment of imaging platforms for drug discovery and manufacture.

In the past more than one fourth century, the reverse redistribution (RR) phenomenon has been explored extensively and deeply, but its pathogenesis and clinical significances have remained unclear, which has perplexed nuclear specialists and cardiologists in the clinical practice. This paper reviewed the spectrum of the RR phenomenon in different entities and in different radiotracers. A close attention has been paid to the clinical significances, clinical approaching strategies and underlying mechanism of reverse redistribution in coronary artery diseases. We think that microcirculation's structure and function impairments may be responsible for reverse redistribution phenomenon.

Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has been recognised as a sensitive tool for the staging of various malignancies, such as lung carcinoma, lymphoma, and esophageal cancer. Its role in staging process of breast cancer however is subject to discussion, mainly due to supposedly lower metabolic activity of the disease. In this article, we discuss the current literature on FDG PET/CT for the staging of breast cancer, including staging of the primary tumour and the axilla, and the detection of distant metastases both in primary and recurrent breast cancer. In addition, we will focus on several methodological aspects and acquisition protocols to optimize the imaging of breast cancer patients by FDG PET/CT.

Sonography has not been generally accepted as an imaging modality for the evaluation of soft tissue tumors. Three-dimensional ultrasonography appears to be a valuable adjunct to conventional ultrasonography because it provides previously unattainable scan planes and three-dimensional views. This new technique allows to display spatially oriented and standardized views, which reduce the operator dependence and improve the reliability of follow-up studies. 3D data processing provides life like display of anatomy and real time guidance of interventional procedures such as biopsy. 3D ultrasound-guided biopsy can be performed by using multiplanar views or a combination of cross sectional and rendered images. Large core biopsies using a vacuum assisted biopsy device (8G) achieve an accuracy in the histopathological assessment of soft tissue sarcoma that is comparable to incisional biopsy. Improved visualization and guidance of interventional procedures by 3D ultrasound may increase the acceptance of clinicians to use sonography for the evaluation of soft tissue tumors.

Super-selective intra-arterial infusion chemotherapy for head and neck cancer via the superficial temporal artery is an established procedure. Three-dimensional computed tomography angiography (3D-CTA) has often been used to assess the arterial anatomy. However, 3D-CTA images are sometimes affected by severe metallic artifacts near the oral cavity region, due to the presence of metallic dental materials. This study has evaluated 3-dimensional intravenous digital subtraction angiography (3D-IV-DSA) using a flat panel detector (FPD) system in vascular mapping of the external carotid artery (ECA), in comparison with 3D-CTA. To clarify the vascular anatomy of ECA branches, 15 patients had undergone both 3D-IV-DSA and 3D-CTA. The angiographic images of the ECA were generated using a volume-rendering technique. The 15 patients were also divided into two groups according to the existence of adverse effects due to dental metallic artifacts on 3D-CTA.Images from 3D-IVDSA were statistically significantly superior to 3D-CTA (P < 0.05). In particular, when metallic artifacts affected 3DCTA images, 3D-IV-DSA was able to depict the ECA more clearly. These findings confirm the utility of 3D-IV-DSA, and the technique may be particularly suitable for patients with metallic dental materials.

Introduction: Craniocervical junction pathologies are seldom pathologies having a vital importance because of their location. That's why preoperative correct evaluation and detection of relation with adjacent tissue of this area pathologies is important for proper treatment plan. Multidetector computed tomography (MDCT) imaging is an improving and being a widely used method recently in many areas of medicine. It is possible to evaluate the peripheric vascular structures, anatomic variations or vascular pathologies with MDCT angiography (MDCTA). Methods: The arcuate foramen is an anatomical variant of the atlas vertebra: anterior and posterior osseous bridges or ponticles can arch over the vertebral artery, to a greater or lesser degree, transforming the arterial groove into a canal. Dissection of the vertebral artery leading to thrombotic occlusion or ischaemia from narrowing of the arterial lumen has been described in trauma. There are fistula between a dural branch of the spinal ramus of a radicular artery and an intradural medullary vein in spinal vascular malformations. MDCT angiography is feasible and is an alternative technique in diagnosis spinal vascular malformations. The craniovertebral junction (CVJ) is a funnel-shaped structure comprised of the clivus and foramen magnum and the upper two cervical vertebrae. The most frequent neoplastic lesions of the craniovertebral junction are meningiomas, neurinomas, chordomas, paragangliomas, epidermoids, dermoids and chondrosarcomas. Conclusion: In this presentation, pathologies seen in craniocervical junction (congenital variation, trauma, vascular malformation and tumor) were discussed with figures and compared with the literature.

Various modalities are available for the diagnosis of diseases affecting the oral and maxillofacial regions. The currently used imaging modalities include intra-oral radiographs, panoramic radiographs, magnetic resonance imaging (MRI), computed tomography (CT) including cone-beam (CB) CT, ultrasonography (US), and nuclear medicine including positron emission tomography (PET). In the present review, we describe the application and significance of each modality in the diagnostic process of oral and maxillofacial diseases.

In current study, visual appearance of pure calcium phosphate (CaP) urinary stones by its morphology from plain radiograph (KUB), were investigated. We reviewed patients with urinary stone disease who underwent stone surgery. Among cases with crystallographically analyzed stones; 60 patients with pure CaP renal or ureteral stones (greater than 1 cm) were selected. Two endourologists and a uroradiologist familiar with the radiographic patterns of different types of pure stones were invited separately, to evaluate pretreatment KUB. Four different radiographic patterns were identified mainly with the assistance of previous studies. Smooth edged, homogenous stones with denser opacity were included in Group 1. Stones with irregular edges and stippled border were included in Group 2. Relatively uniform stones with radial striations and moderate density were decided to form Group 3. Calculi with the least radiodensity and loosely aggregated with a lacy structure were included in Group 4. Overall, 68.9% of CaP calculi were included in Groups 1 and 2 by all participants. Best concordance between endourologists and the uroradiologist was demonstrated in the evaluation of smaller calculi (< 150 mm2). On KUB, CaP urinary calculi were mostly seen as dense relatively homogenous stones and sometimes with stippled borders. With an increase in pretreatment stone size, interobserver and interdisciplinary variabilities increased.

Nuclear Molecular Imaging enables in vivo characterization and measurement of biologic processes at the cellular and molecular level. This technique contributes to improving the treatment of disorders as well as facilitating in drug discovery and development. The facilities and technologies for developing molecular probes have been established in Taiwan. Institute of Nuclear Energy Research (INER) has built a compact cyclotron and Radiopharmaceutical Production Center, a factory in compliance with the cGMP regulations. In view of the potentialities of molecular imaging in drug discovery and development, INER has set up dedicated imaging facilities including microPET, microSPECT, microCT, and optical imaging. These facilities offer state-of-the-art imaging technology, not only supporting INER's research projects but also providing imaging services for domestic pharmaceutical industry or research institutes. The nuclear imaging research and development in Taiwan covers many fields including (1) development of radiopharmaceuticals for imaging central nervous system disorders, (2) development of radiopharmaceuticals for cancer imaging, (3) development of therapeutic radiopharmaceuticals targeting to specific cancer, and (4) establishment of imaging platforms for drug discovery and development. Up to now INER has commercialized 15 radiopharmaceuticals such as 99mTc-TRODAT-1, Thallum- 201, 18F-FDG… etc. INER also develops some radiopharmaceuticals like 123I-ADAM for depression imaging, 18F-FLT for DNA synthesis, 123I-IBZM for Dopamine D2 receptor, 18F-FDDNP for β-amyloid plaques imaging … etc. Nanotechnology imaging will soon be established in Taiwan, we are engaged in developing 188Re-GalNAC-Folic acid nanoparticle and targeted and combined therapies for the management of specific cancers. By integrating domestic resources and collaboration with international researchers and physicians, we will continuously devote ourselves to exploration of the mechanisms of neuropsychiatric diseases, development of the radiopharmaceuticals for cancer diagnosis or treatment, and establishment of molecular imaging platforms for providing drug evaluation service.