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Department of Diagnostic Radiology

Masahiko Kusumoto, Ryoko Iwata, Yoshihiro Nakagami, Tatsushi Kobayashi, Kaoru Shimada, Kotaro Sekiya, Hirohumi Kuno

Introduction

The Department of Diagnostic Radiology is committed to improving health through excellence in image-oriented patient care and research. Our Department performs more than 96,000 inpatient and outpatient procedures annually. The department also conducts clinical scientific research as well as basic scientific studies, with the results translated directly into better patient care.

Routine activities

Our Department has four multi-slice computed tomography (CT) scanners including two area detector CT scanners and one Dual Source CT, two 3T magnetic resonance imaging (MRI) systems, one interventional radiology (IR) CT system, one Multi-axis c-arm CT system, two gamma cameras with the capacity for single photon emission CT (SPECT), two digital radiographic (DR) systems for fluoroscopy, two mammographies (MMG), and four computed radiographic (CR) systems. Our IRCT systems use digital subtraction angiography with multi-detector computerized tomography (MDCT). One is equipped with a 320 multi-slice CT. A positron emission tomography (PET) scanner and baby cyclotron have been installed, and tumor imaging using 18F-FDG (fluorodeoxyglucose) has been performed. These all-digital image systems enhance the efficacy of routine examinations.

This department has seven consulting radiologists and 22 technologists. As part of our routine activities, every effort is made to produce an integrated report covering almost all examinations, such as MMG, contrast radiological procedures, CT, MRI, RI, PET, angiography and IR, mainly transarterial chemoembolization (TACE).

The number of cases examined in 2015 is shown in the Table below. Several conferences are routinely held at our department including preand postoperative conferences. Furthermore, our Department contributes to decide treatment strategy through the image presentation at the weekly tumor board conference (especially, Hepatobiliary-Pancreatic and Head-Neck regions).

Research activities

The research activities of the Department of Diagnostic Radiology focus on diagnostic imaging and IR. These activities consist of 1) Development of new CT/MRI technology and 2) Development of new Nuclear Medicine tracers. The department also conducts clinical scientific research as well as basic scientific studies, with the results translated directly into better patient care.

Development of new CT/MRI technology

In the study with dual energy CT, for the larynx, hypopharynx, thyroid cancers and lymph node metastasis, the possibility of a quantitative evaluation with iodine uptake value measuring and histogram generation using monochromatic imaging technique have been confirmed. The results of this preliminary study have suggested that the quantitative analysis of tumors may aid differential diagnosis and the lymph node metastasis detection.

In 320-row area-detector CT, it is found that the effect of SEMAR (single energy metal artifact reduction: the algorithm to reduce metal artifacts without increasing the X-ray dose) influenced by the location of metal materials at the scan. In addition, it has been confirmed that the location adjustment of the metal materials can increase the effect of SEMAR and CT image quality. Furthermore, in the other study with 320-row area-detector CT, using the area-detector CT features as a four dimensional CT, the relationship between the perfusion parameters of the pancreas and the frequency of the post-operative complication have been investigated.

In the 3-Tesla MR study, the imaging quality of mandibular cross-sect ional mul t iplanar reconstruction (CS-MPR) using 3D sequences has been improved by optimization of the 3D imaging process. This optimization provides more accurate evaluation of bone marrow invasion.

In another study using 3T-MRI, the vessels of the tongue have been visualized by bright-blood time with a 3D sequence. It is suggested that this bright-blood imaging technique will provide more sensitive lymph node metastasis detection because the tongue cancer invasion into the lingual vascular bundle is known as a predictor of lymph node metastasis.

Development of new Nuclear Medicine tracers

Small interfering RNAs (siRNAs) were discovered as a promising gene silencing tool in research and in the clinic, and we succeeded in radiolabeling siRNA last year. However, siRNA is unstable for RNase in the living body. Therefore, the transfection reagent is usually required when siRNA is given to the living body.

We compared the degree of resistance against RNaseA among unlabeled siRNA, naked radiolabeled siRNA and radiolabeled siRNA with the transfection reagent. For Radiolabeled siRNA with the transfection reagent, slightly less than 60% of the RNA remained at 60 minutes after adding RNaseA. On the other hand, for naked unlabeled siRNA, almost all siRNA was broken down at seven minutes after adding RNaseA. For naked radiolabeled siRNA only, slightly over 30% of the RNA remained at 60 minutes after adding RNaseA, although we did not use the transfection reagent.

The results suggest that our labeled siRNA is stable not only as a complex with transfection reagents but also as naked labeled siRNA and should be deliverable to the specific regions overexpressing the target gene.


Table 1. Number of Anesthesia Cases

List of papers published in 2015

Journal

  1. Sugimoto M, Takahashi S, Kobayashi T, Kojima M, Gotohda N, Satake M, Ochiai A, Konishi M. Pancreatic perfusion data and post-pancreaticoduodenectomy outcomes. J Surg Res, 194:441-449, 2015
  2. Murata S, Onozawa S, Mine T, Ueda T, Sugihara F, Yasui D, Kumita S, Satake M. Retrograde-outflow percutaneous isolated hepatic perfusion using cisplatin: A pilot study on pharmacokinetics and feasibility. Eur Radiol, 25:1631-1638, 2015
  3. Kakinuma R, Muramatsu Y, Kusumoto M, Tsuchida T, Tsuta K, Maeshima AM, Asamura H, Moriyama N. Solitary pure groundglass nodules 5 mm or smaller: frequency of growth. Radiology, 276:873-882, 2015
  4. Watanabe Y, Kusumoto M, Yoshida A, Suzuki K, Asamura H, Tsuta K. Surgically resected solitary cavitary lung adenocarcinoma: association between clinical, pathologic, and radiologic findings and prognosis. Ann Thorac Surg, 99:968-974, 2015
  5. Okada H, Kaneda T, Sekiya K, Kawashima Y, Suemitsu M, Hayakawa Y, Sakae T. Basic study of parametric X-ray radiation for clinical diagnosis using 125MeV linear particle accelerator. J Hard Tissue Biol, 24:299-302, 2015
  6. Kaneda T, Sekiya K, Suemitsu M, Sakae T, Hayakawa Y, Kawashima Y, Hirahara N, Muraoka H, Ito K, Muramatsu T, Ishida M, Okada H. Preliminary clinical application study of parametric X-rays in diagnostic imaging. Int J Oral-Med Sci, 14:8-12, 2015
  7. Sekiya K, Ishida M, Sekiya K, Suemitsu M, Hara Y, Kaneda T. A case of impacted tooth in the maxillary sinus: CT findings. Int J Oral-Med Sci, 13:128-130, 2015