Faculty Profiles - NAGANAWA, Shinji

Papers - NAGANAWA, Shinji

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Diffusion-weighted image analysis along the perivascular space (DWI-ALPS) for evaluating interstitial fluid status: age dependence in normal subjects. Reviewed

Toshiaki Taoka, Rintaro Ito, Rei Nakamichi, Toshiki Nakane, Mayuko Sakai, Kazushige Ichikawa, Hisashi Kawai, Shinji Naganawa

Japanese journal of radiology Vol. 40 ( 9 ) page： 894 - 902 2022.9

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The purpose of this study was to evaluate the interstitial fluid status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, which is a simplified variation of diffusion tensor image analysis along the perivascular space (DTI-ALPS). MATERIALS AND METHODS: This retrospective study included data from 128 patients who underwent clinical magnetic resonance imaging (MRI) studies, including DWI, and were found to have no abnormal findings in the brain on MRI. Three motion-probing gradients of the DWI were applied in an orthogonal direction to the imaging plane. Apparent diffusion coefficient images in the x-, y-, and z-axes were retrospectively generated, and composite color images were created to locate the projection and association fiber area on the slice including the body of the lateral ventricle. ALPS indices were calculated, and correlations with age were evaluated using linear and second-degree regression analysis. Linear regression analysis was also performed for a subgroup of patients older than 40 years. In addition, an analysis of variance (ANOVA) test among the generations was performed. RESULTS: The linear regression analysis between age and the ALPS index showed a correlation coefficient of -0.20 for all age group and -0.51 for the subgroup older than 40 years. The second-degree regression analysis showed a correlation coefficient of 0.39. ANOVA showed that the 40's generation showed a statistically significant higher value of ALPS index compared to all other generations except for the 30's generation. While, the 70's generation showed a statistically significant lower value of the ALPS index compared to all other generations. CONCLUSIONS: The analysis of the DWI-APLS method showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation. This finding in normal subjects may be fundamental in the analysis of disease cases. We tried to evaluate the glymphatic system status in a wide range of age groups using diffusion-weighted image analysis along the perivascular space (DWI-ALPS) method, and the results showed a correlation between age and the ALPS index in second-degree distribution which peaked in the 40's generation.

DOI： 10.1007/s11604-022-01275-0

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PubMed

人工知能を応用したバーチャル3D thin-section CTを用いた肺腺癌の充実成分径の計測 Reviewed

岩野信吾, 神谷晋一朗, 伊藤倫太郎, 工藤彰, 北村嘉郎, 中村圭児, 長縄慎二

断層映像研究会雑誌 Vol. 49 ( 2 ) page： 39 - 39 2022.9

Development of a high-resolution two-dimensional detector-based dose verification system for tumor-tracking irradiation in the CyberKnife system. Reviewed International journal

Fumitaka Kawabata, Takeshi Kamomae, Kuniyasu Okudaira, Masataka Komori, Hiroshi Oguchi, Motoharu Sasaki, Masaki Mori, Mariko Kawamura, Shinji Abe, Shunichi Ishihara, Shinji Naganawa

Journal of applied clinical medical physics Vol. 23 ( 8 ) page： e13645 - e13645 2022.8

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

We aim to evaluate the basic characteristics of SRS MapCHECK (SRSMC) for CyberKnife (CK) and establish a dose verification system using SRSMC for the tumor-tracking irradiation for CK. The field size and angular dependence of SRSMC were evaluated for basic characterization. The output factors (OPFs) and absolute doses measured by SRSMC were compared with those measured using microDiamond and microchamber detectors and those calculated by the treatment planning system (TPS). The angular dependence was evaluated by comparing the SRSMC with a microchamber. The tumor-tracking dose verification system consists of SRSMC and a moving platform. The doses measured using SRSMC were compared with the doses measured using a microchamber and radiochromic film. The OPFs and absolute doses of SRSMC were within ±3.0% error for almost all field sizes, and the angular dependence was within ±2.0% for all incidence angles. The absolute dose errors between SRSMC and TPS tended to increase when the field size was smaller than 10 mm. The absolute doses of the tumor-tracking irradiation measured using SRSMC and those measured using a microchamber agreed within 1.0%, and the gamma pass rates of SRSMC in comparison with those of the radiochromic film were greater than 95%. The basic characteristics of SRSMC for CK presented acceptable results for clinical use. The results of the tumor-tracking dose verification system realized using SRSMC were equivalent to those of conventional methods, and this system is expected to contribute toward improving the efficiency of quality control in many facilities.

DOI： 10.1002/acm2.13645

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Contrast-Enhanced Fluid-Attenuated Inversion Recovery in Neuroimaging: A Narrative Review on Clinical Applications and Technical Advances. Reviewed International journal

Sung Jun Ahn, Toshiaki Taoka, Won-Jin Moon, Shinji Naganawa

Journal of magnetic resonance imaging : JMRI Vol. 56 ( 2 ) page： 341 - 353 2022.8

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

While contrast-enhanced fluid-attenuated inversion recovery (FLAIR) has long been regarded as an adjunct sequence to evaluate leptomeningeal disease in addition to contrast-enhanced T1-weighted imaging, it is gradually being used for more diverse pathologies beyond leptomeningeal disease. Contrast-enhanced FLAIR is known to be highly sensitive to low concentrations of gadolinium within the fluid. Accordingly, recent research has suggested the potential utility of contrast-enhanced FLAIR in various kinds of disease, such as Meniere's disease, seizure, stroke, traumatic brain injury, and brain metastasis, in addition to being used for visualizing glymphatic dysfunction. However, its potential applications have been reported sporadically in an unorganized manner. Furthermore, the exact mechanism for its superior sensitivity to low concentrations of gadolinium has not been fully understood. Rapidly developing magnetic resonance technology and unoptimized parameters for FLAIR may challenge its accurate application in clinical practice. This review provides the fundamental mechanism of contrast-enhanced FLAIR, systematically describes its current and potential clinical application, and elaborates on technical considerations for its optimization. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 5.

DOI： 10.1002/jmri.28117

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PubMed

The Incidence and Its Associated Factors Relevant to Brain Radionecrosis That Requires Intervention Following Single or Fractionated Stereotactic Radiosurgery Using Vero4DRT for Brain Metastases Reviewed

Takehiro Yamada, Kazuhiro Ohtakara, Takeshi Kamomae, Junji Itoh, Hideki Shimada, Shunichi Ishihara, Shinji Naganawa

CUREUS JOURNAL OF MEDICAL SCIENCE Vol. 14 ( 6 ) page： e25888 - e25888 2022.6

Embolization using patient-specific vascular models created by a 3D printer for difficult cases: a report of two cases. Reviewed Open Access

Tomohiro Komada, Takeshi Kamomae, Masaya Matsushima, Ryota Hyodo, Shinji Naganawa

Nagoya journal of medical science Vol. 84 ( 2 ) page： 477 - 483 2022.5

Language：English Publishing type：Research paper (scientific journal)

With the widespread use of three-dimensional printers, organ models created by these printers are now being used in the medical field for preoperative planning of surgeries. In this article, we report two cases in which embolization was expected to be difficult, and the three-dimensional printer-based vascular modeling was helpful in planning the surgery. The first case involved an aneurysm of the splenic artery. We attempted to embolize the aneurysm but were unable to advance the catheter into the distal artery and discontinued the procedure. The second case was a perianal varicose vein, which was initially treated with percutaneous transhepatic obliteration but was recanalized and required embolization. However, we expected difficulty in selecting the inferior mesenteric vein. In both cases, the vascular models were created using a 3D printer from the patients' computed tomography images. Preoperative planning, including treatment simulation, was based on these models. The time required to print a three-dimensional vascular model was approximately 12 hours at a cost of less than $10 each. Patient-specific vascular models using a three-dimensional printer can be a simple and inexpensive tool that can increase the success of embolization in difficult cases.

DOI： 10.18999/nagjms.84.2.477

Open Access

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PubMed

Letter to editor on the article "A non-invasive, automated diagnosis of Menière's disease using radiomics and machine learning on conventional magnetic resonance imaging: a multicentric, case-controlled feasibility study" by van der Lubbe Mfja et al. Reviewed International journal

Shinji Naganawa, Rintaro Ito, Toshiaki Taoka, Tadao Yoshida, Michihiko Sone

La Radiologia medica Vol. 127 ( 4 ) page： 458 - 459 2022.4

Does the Pulsatile Non-uniform Flow Matter in MR Flowmetry? Reviewed

Masataka Sugiyama, Yasuo Takehara, Shinji Naganawa

Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine Vol. 21 ( 2 ) page： 365 - 371 2022.3

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

3D cine phase-contrast (4D flow) MRI is a sequence with great potential for non-invasive time-resolved 3D flowmetry at arbitrary vessel sections in various blood vessels. However, it is not widely known that the flowmetry with 4D flow MRI is vulnerable to pulsatile and non-uniform flow. Due to the limited spatial and temporal resolutions, averaging within the 3D voxel is occurring during the flowmetry. A simple solution is to avoid setting the measurement plane in the area where non-uniform flow is dominant, which is possible with an aid of streamline depictions generated by computational fluid dynamics (CFD) or 4D flow MRI data. Unlike 4D flow MRI, flowmetry in CFD simulation can use higher spatial and temporal resolution depending on computer performance; therefore, it is robust to fluctuating non-uniform flow. However, the performance of CFD simulations might be limited due to inlet conditions with low temporal resolution. Difficulty applying complex blood flow such as reflection flow from periphery may also limit accurate simulation. Caution should be taken when comparing the result of CFD simulation to that of 4D flow measurement.

DOI： 10.2463/mrms.rev.2021-0099

PubMed

Hybrid 3D T1-weighted gradient-echo sequence for fiducial marker detection and tumor delineation via magnetic resonance imaging in liver stereotactic body radiation therapy. Reviewed International journal

Yutaka Kato, Takeshi Kamomae, Motoki Kumagai, Yumi Oie, Yumiko Noguchi, Kuniyasu Okudaira, Mariko Kawamura, Toshiaki Taoka, Shinji Naganawa

Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) Vol. 95 page： 9 - 15 2022.3

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

PURPOSE: Gold fiducial markers are used to guide liver stereotactic body radiation therapy (SBRT) and are hard to detect by magnetic resonance imaging (MRI). In this study, the parameters of the three-dimensional T1-weighted turbo gradient-echo (3D T1W-GRE) sequence were optimized for gold marker detection without degrading tumor delineation. METHODS: Custom-made phantoms mimicking tumor and normal liver parenchyma were prepared and embedded with a gold marker. The 3D T1W-GRE was scanned by varying echo time (TE), bandwidth (BW), flip angle (FA), and base matrix size. The signal-to-noise ratio (SNR), contrast ratio (CR), and relative standard deviation (RSD) of the signal intensity in the area including the gold marker were evaluated, and the parameters were optimized accordingly. The modified 3D T1W-GRE (called HYBRID) was compared with the conventional T1W-GRE- and T2*-sequences in both phantom and clinical studies. In the clinical study of six patients with primary liver tumors, two observers visually assessed marker detection, tumor delineation, and overall image quality on a four-point scale. RESULTS: In the phantom study, HYBRID showed significantly higher SNR and RSD than those of conventional T1W-GRE (P < 0.001). In the clinical study, HYBRID yielded significantly higher scores than conventional T1W-GRE did in terms of marker detection (P < 0.001). The scores of both sequences were not statistically different in terms of tumor delineation and overall image quality (P = 0.56 and P = 0.32). CONCLUSIONS: The proposed HYBRID sequence improved gold fiducial marker detection without degrading tumor delineation in MRI for SBRT of primary liver tumor.

DOI： 10.1016/j.ejmp.2022.01.003

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PubMed

歪みのないMRI拡散強調画像の放射線治療計画への臨床応用 Reviewed

加藤裕, 奥平訓康, 丸山克也, 田岡俊昭, 長縄慎二

日本放射線技術学会総会学術大会予稿集 Vol. 78回 page： 169 - 169 2022.3

17O標識水と市販点眼薬の画像化に向けた初期検討 Ultra-heavily T2強調画像の可能性 Invited

加藤裕, 山口博司, 田岡俊昭, 長縄慎二

日本放射線技術学会総会学術大会予稿集 Vol. 78回 page： 190 - 190 2022.3

コークスクリュー型高速パラレルイメージング併用3D-FLAIRシーケンスの基礎的検討 Reviewed

加藤裕, 田岡俊昭, 丸山克也, 長縄慎二

日本放射線技術学会総会学術大会予稿集 Vol. 78回 page： 214 - 214 2022.3

Water Diffusivity Changes Along the Perivascular Space After Lumboperitoneal Shunt Surgery in Idiopathic Normal Pressure Hydrocephalus. Reviewed International journal

Junko Kikuta, Koji Kamagata, Toshiaki Taoka, Kaito Takabayashi, Wataru Uchida, Yuya Saito, Christina Andica, Akihiko Wada, Kaito Kawamura, Chihiro Akiba, Madoka Nakajima, Masakazu Miyajima, Shinji Naganawa, Shigeki Aoki

Frontiers in neurology Vol. 13 page： 843883 - 843883 2022.2

Language：English Publishing type：Research paper (scientific journal)

Background: The aim of this study was to evaluate the water diffusivity changes along the perivascular space after lumboperitoneal shunt (LPS) surgery in idiopathic normal pressure hydrocephalus. Methods: Nine patients diagnosed with idiopathic normal pressure hydrocephalus (iNPH; three men and six women, mean age ± SD = 75.22 ± 5.12 years) according to the guidelines for iNPH in Japan were included in the study. Post-LPS surgery, six patients with iNPH who exhibited improvement in symptoms were defined as responder subjects, while three patients with iNPH who did not were defined as non-responder subjects. We calculated the mean analysis along the perivascular space (ALPS) index of the left and right hemispheres and compared the differences between pre- and post-LPS surgery mean ALPS indices in iNPH patients. In the responder or non-responder subjects, the mean ALPS indices in the pre- and post-operative iNPH groups were compared using Wilcoxon signed-rank tests. Next, correlation analyses between pre- and post-operation changes in the mean ALPS index and clinical characteristics were conducted. Results: The mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (p = 0.021). In responder subjects, the mean ALPS index of the post-operative iNPH group was significantly higher than that of the pre-operative iNPH group (p = 0.046). On the other hand, in the non-responder subjects, the mean ALPS index of the post-operative iNPH group was not significantly different compared to the pre-operative iNPH group (p = 0.285). The mean ALPS index change was not significantly correlated with changes in the Mini-Mental State Examination (MMSE) score (r = -0.218, p = 0.574), Frontal Assessment Battery (FAB) score (r = 0.185, p = 0.634), Trail Making Test A (TMTA) score (r = 0.250, p = 0.516), and Evans' index (r = 0.109, p = 0.780). In responder subjects, the mean ALPS index change was significantly correlated with Evans' index in pre-operative patients with iNPH (r = 0.841, p = 0.036). Conclusion: This study demonstrates the improved water diffusivity along perivascular space in patients with iNPH after LPS surgery. This could be indicative of glymphatic function recovery following LPS surgery.

DOI： 10.3389/fneur.2022.843883

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PubMed

中枢神経原発の成人T細胞白血病・リンパ腫の1例 Reviewed

長井尚哉, 川井恒, 田岡俊昭, 伊藤信嗣, 長縄慎二, 加賀谷裕介, 寺倉精太郎, 横井聡, 勝野雅央, 河野奨, 下山芳江

Japanese Journal of Radiology Vol. 40 ( Suppl. ) page： 25 - 25 2022.2

Reproducibility of diffusion tensor image analysis along the perivascular space (DTI-ALPS) for evaluating interstitial fluid diffusivity and glymphatic function: CHanges in Alps index on Multiple conditiON acquIsition eXperiment (CHAMONIX) study. Reviewed

Toshiaki Taoka, Rintaro Ito, Rei Nakamichi, Koji Kamagata, Mayuko Sakai, Hisashi Kawai, Toshiki Nakane, Takashi Abe, Kazushige Ichikawa, Junko Kikuta, Shigeki Aoki, Shinji Naganawa

Japanese journal of radiology Vol. 40 ( 2 ) page： 147 - 158 2022.2

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method was developed to evaluate the brain's glymphatic function or interstitial fluid dynamics. This study aimed to evaluate the reproducibility of the DTI-ALPS method and the effect of modifications in the imaging method and data evaluation. MATERIALS AND METHODS: Seven healthy volunteers were enrolled in this study. Image acquisition was performed for this test-retest study using a fixed imaging sequence and modified imaging methods which included the placement of region of interest (ROI), imaging plane, head position, averaging, number of motion-proving gradients, echo time (TE), and a different scanner. The ALPS-index values were evaluated for the change of conditions listed above. RESULTS: This test-retest study by a fixed imaging sequence showed very high reproducibility (intraclass coefficient = 0.828) for the ALPS-index value. The bilateral ROI placement showed higher reproducibility. The number of averaging and the difference of the scanner did not influence the ALPS-index values. However, modification of the imaging plane and head position impaired reproducibility, and the number of motion-proving gradients affected the ALPS-index value. The ALPS-index values from 12-axis DTI and 3-axis diffusion-weighted image (DWI) showed good correlation (r = 0.86). Also, a shorter TE resulted in a larger value of the ALPS-index. CONCLUSION: ALPS index was robust under the fixed imaging method even when different scanners were used. ALPS index was influenced by the imaging plane, the number of motion-proving gradient axes, and TE in the imaging sequence. These factors should be uniformed in the planning ALPS method studies. The possibility to develop a 3-axis DWI-ALPS method using three axes of the motion-proving gradient was also suggested.

DOI： 10.1007/s11604-021-01187-5

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＜Editors' Choice＞ Evaluation of system-related magnetic resonance imaging geometric distortion in radiation therapy treatment planning: two approaches and effectiveness of three-dimensional distortion correction.

Yutaka Kato, Kuniyasu Okudaira, Takeshi Kamomae, Motoki Kumagai, Youta Nagai, Toshiaki Taoka, Yoshiyuki Itoh, Shinji Naganawa

Nagoya journal of medical science Vol. 84 ( 1 ) page： 29 - 41 2022.2

Language：English Publishing type：Research paper (scientific journal)

We propose two methods to evaluate system-related distortion in magnetic resonance imaging (MRI) in radiation therapy treatment planning (RTP) and demonstrate the importance of three-dimensional (3D) distortion correction (DC) by quantitatively measuring the distortion magnitude. First, a small pin phantom was scanned at multiple positions using an external laser guide for accurate phantom placement and combined into one image encompassing a large area. Direct plane images were used for evaluating in-plane distortion and multiplanar reconstruction images for through-plane distortion with no DC, two-dimensional (2D) DC, and 3D DC. Second, a large grid sheet was scanned as the direct plane of the phantom placement. The distortion magnitude was determined by measuring the displacement between the MRI and reference coordinates. The measured distortions were compared between in- and through-plane when applying DC and between the two methods. The small pin phantom method can be used to evaluate a wide range of distortions, whereas data from the entire plane can be obtained with a single scan using the grid sheet without a laser guide. The mean distortion magnitudes differed between the methods. Furthermore, the 3D DC reduced in- and through-plane distortions. In conclusion, the small pin phantom method can be used to evaluate a wide range of distortions by creating a combined image, whereas the grid sheet method is simpler, accurate, repeatable, and does not require a special-order phantom or laser guide. As 3D DC reduces both in- and through-plane distortions, it can be used to improve RTP quality.

DOI： 10.18999/nagjms.84.1.29

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Labyrinthitis With Endolymphatic Hydrops Revealed by Imaging Analysis in a Case With Severe Postoperative Complications Following Stapes Surgery. Reviewed International journal

Masumi Kobayashi, Tadao Yoshida, Yasue Uchida, Satofumi Sugimoto, Shinji Naganawa, Michihiko Sone

Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology Vol. 43 ( 1 ) page： E134 - E136 2022.1

Features from MRI texture analysis associated with survival outcomes in triple-negative breast cancer patients. Reviewed

Saki Kamiya, Hiroko Satake, Yoko Hayashi, Satoko Ishigaki, Rintaro Ito, Mariko Kawamura, Toshiaki Taoka, Shingo Iwano, Shinji Naganawa

Breast cancer (Tokyo, Japan) Vol. 29 ( 1 ) page： 164 - 173 2022.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

PURPOSE: The purpose of the study is to evaluate the associations between intratumoral or peritumoral textural features derived from pretreatment magnetic resonance imaging (MRI) and recurrence-free survival (RFS) in triple-negative breast cancer (TNBC) patients. METHODS: Forty-three patients with TNBC who underwent preoperative MRI between February 2008 and March 2014 were included. We performed two-dimensional texture analysis on the intratumoral or peritumoral region of interest (ROI) on axial of T2-weighted image (T2WI), dynamic contrast-enhanced (DCE)-MRI and DCE-MRI subtraction images. We also analyzed histopathological data. Cox proportional hazards models were used to investigate associations with survival outcomes. RESULTS: Twelve of the 43 patients (27.9%) had recurrence disease, at a median of 32.5 months follow-up (1.4-61.5 months). In univariate analysis, nine texture features in T2WI and DCE-MRI subtraction images were significantly associated with RFS. In multivariate analysis, intratumoral difference entropy in DCE-MRI subtraction images in the initial phase (hazard ratio 11.71; 95% confidence interval (CI) [1.41, 97.00]; p value 0.023) and, peritumoral difference variance in DCE-MRI subtraction images in the delayed phase (hazard ratio 9.60; 95% CI [1.98, 46.51]; p value 0.005), were both independently associated with RFS. Moreover, multivariate analysis revealed the presence of lymphovascular invasion as independently associated with RFS (hazard ratio 8.13; 95% CI [2.16, 30.30]; p value 0.002). CONCLUSIONS: At pretreatment MRI, an intratumoral and peritumoral quantitative approach using texture analysis has the potential to serve as a prognostic marker in patients with TNBC.

DOI： 10.1007/s12282-021-01294-1

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Radiomics in breast MRI: current progress toward clinical application in the era of artificial intelligence. Reviewed International journal

Hiroko Satake, Satoko Ishigaki, Rintaro Ito, Shinji Naganawa

La Radiologia medica Vol. 127 ( 1 ) page： 39 - 56 2022.1

Authorship：Last author Language：English Publishing type：Research paper (scientific journal)

Breast magnetic resonance imaging (MRI) is the most sensitive imaging modality for breast cancer diagnosis and is widely used clinically. Dynamic contrast-enhanced MRI is the basis for breast MRI, but ultrafast images, T2-weighted images, and diffusion-weighted images are also taken to improve the characteristics of the lesion. Such multiparametric MRI with numerous morphological and functional data poses new challenges to radiologists, and thus, new tools for reliable, reproducible, and high-volume quantitative assessments are warranted. In this context, radiomics, which is an emerging field of research involving the conversion of digital medical images into mineable data for clinical decision-making and outcome prediction, has been gaining ground in oncology. Recent development in artificial intelligence has promoted radiomics studies in various fields including breast cancer treatment and numerous studies have been conducted. However, radiomics has shown a translational gap in clinical practice, and many issues remain to be solved. In this review, we will outline the steps of radiomics workflow and investigate clinical application of radiomics focusing on breast MRI based on published literature, as well as current discussion about limitations and challenges in radiomics.

DOI： 10.1007/s11547-021-01423-y

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Reserve and maintenance in the aging brain: A longitudinal study of healthy older adults. Reviewed International journal

Epifanio Bagarinao, Hirohisa Watanabe, Satoshi Maesawa, Kazuya Kawabata, Kazuhiro Hara, Reiko Ohdake, Aya Ogura, Daisuke Mori, Noritaka Yoneyama, Kazunori Imai, Takamasa Yokoi, Toshiyasu Kato, Shuji Koyama, Masahisa Katsuno, Toshihiko Wakabayashi, Masafumi Kuzuya, Minoru Hoshiyama, Haruo Isoda, Shinji Naganawa, Norio Ozaki, Gen Sobue

eNeuro Vol. 9 ( 1 ) page： 0455-21 - 0455-21 2022.1

Language：English Publishing type：Research paper (scientific journal)

The aging brain undergoes structural changes even in very healthy individuals. Quantifying these changes could help disentangle pathological changes from those associated with the normal human aging process. Using longitudinal MRI data from 227 carefully selected healthy human cohort with age ranging from 50 to 80 years old at baseline scan, we quantified age-related volumetric changes in the brain of healthy human older adults. Longitudinally, the rates of tissue loss in total gray matter (GM) and white matter were 2,497.5 mm3 per year and 2,579.8 mm3 per year, respectively. Across the whole brain, the rates of GM decline varied with regions in the frontal and parietal lobes having faster rates of decline, whereas some regions in the occipital and temporal lobes appeared relatively preserved. In contrast, cross sectional changes were mainly observed in the temporal-occipital regions. Similar longitudinal atrophic changes were also observed in subcortical regions including thalamus, hippocampus, putamen, and caudate, whereas the pallidum showed an increasing volume with age. Overall, regions maturing late in development (frontal, parietal) are more vulnerable to longitudinal decline, whereas those that fully mature in the early stage (temporal, occipital) are mainly affected by cross sectional changes in healthy older cohort. This may suggest that, for a successful healthy aging, the former needs to be maximally developed at an earlier age to compensate for the longitudinal decline later in life and the latter to remain relatively preserved even in old age, consistent with both concepts of reserve and brain maintenance.Significance StatementAging is associated with gray matter (GM) decline, yet some individuals tend to remain cognitively healthy even in advanced age. What differentiates the brains of "healthy agers" from those individuals who are prone to faster cognitive decline still remains unclear. Using longitudinal MRI data from a carefully selected cohort, we examined the brain aging characteristics of healthy agers. Our findings showed that, even in this population, frontal-parietal regions have faster longitudinal rate of GM decline, whereas some temporal-occipital regions appeared relatively preserved. These findings may suggest that, for a successful healthy aging, frontal-parietal regions need to be maximally developed to compensate for the longitudinal decline later in life and the temporal-occipital regions to remain relatively preserved even in old age.

DOI： 10.1523/ENEURO.0455-21.2022

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Papers - NAGANAWA, Shinji