• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.317-323
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• 2020

The aims of this study were to describe the appearance and size of the normal canine prostate using magnetic resonance (MR) imaging and to calculate the apparent diffusion coefficient (ADC) values. MR images were obtained from seven intact male beagle dogs using a 1.5 T MR unit. The sequences included pre- and post-contrast T1- and T2-weighted imaging with and without fat saturation. The signal intensity of the prostate was compared with the adjacent musculature, fat, and urine in the urinary bladder. We recorded the mean prostatic length, width, and height and the length of the sixth lumbar vertebral body (L6). In addition, the prostatic length (rL), width (rW), and height (rH) ratios to L6 were calculated. Diffusion-weighted images of the prostate were obtained and ADC values were calculated. The prostate was bilobed and oval-shaped, homogenous on T1-weighted images, and heterogeneous with radiating lines on T2-weighted images. Post-contrast T1-weighted sequences showed contrast enhancement of the central and radiating striations. The prostatic capsule was clearly identified on post-contrast T1-weighted images with fat saturation. The ADC values were 1.72-2.04 × 10-3mm2/sec (mean, 1.88 × 10-3mm2/sec). Knowledge of the normal appearance of the prostate on MR images is essential to assess prostatic diseases in dogs.

• Investigative Magnetic Resonance Imaging
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• v.17 no.1
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• pp.47-49
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• 2013

Endogenous endophthalmitis is rare and refers to an intraocular inflammatory process that may result from exogenous or endogenous causes. Magnetic resonance imaging (MRI) is useful for diagnosing endophthalmitis, and valuable to reach the diagnosis of brain abscess. We report here the MR findings of simultaneously developed endogenous endophthalmitis and brain abscesses.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.374-380
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• 2019

Collision tumor is a synchronous neoplasm wherein two histologically distinct tumors co-exist within the same anastomosis site. Collision tumor can occur in any organ, but the incidence is markedly rare. Additionally, preoperative diagnosis can be challenging to the radiologist. Herein, we report an age 60 male with collision tumor of rectal adenocarcinoma and diffuse large B-cell lymphoma, presented as a semi-annular wall thickening and bulky exophytic mass on MR imaging.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.12-13
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• 2002

• Investigative Magnetic Resonance Imaging
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• v.11 no.1
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• pp.54-57
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• 2007

Localized nodular synovitis of the knee joint is a rare benign tumorous condition, and should be differentially diagnosed with pigmented villonodular synovitis. We report a case of localized nodular synovitis in the knee that was noted to have a pedicle and characteristic findings on MR image.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.1-8
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• 2016

The spine is the most common location for skeletal metastases, and the incidence of spinal metastasis shows an increasing tendency. Because metastatic spinal tumors progress from an anterior element to a posterior element resulting in continuing destruction of the pedicles, epidural extension and involvement of neural structures of the metastatic tumor are eventually visible. Therefore, it is clinically significant for radiologists to understand the pathophysiology of spinal metastasis and to assess the involvement of neural structures and the disintegration of spinal instability related to the pathophysiology. As MRI is also the best imaging modality for diagnosing spinal metastasis, radiologists should accurately assess spinal metastasis and provide practical information to physicians. Therefore, we will describe some analysis points focusing on the understanding of pathophysiology of spinal metastasis and the next step toward a more extensive clinical approach using MR imaging.

• Investigative Magnetic Resonance Imaging
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• v.19 no.2
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• pp.127-130
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• 2015

Direct injection of foreign material, such as liquid paraffin and silicone, into the breast can induce a foreign body granulomatous reaction and fibrosis, resulting in hard, nodular breast masses and architectural distortion that can mimic neoplasm. Conventional methods, including physical examination, mammography, and ultrasonography are of little use to differentiate between foreign body-induced mastopathy and breast cancer. In patients with foreign body injection such as breast augmentation, dynamic contrast enhanced MR imaging is an excellent imaging modality. Here, the authors report the MR imaging and pathological findings of ductal carcinoma in situ (DCIS) with multicystic changes in a 41-year-old woman with a previous history of interstitial mammoplasty by paraffin injection.

• Investigative Magnetic Resonance Imaging
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• v.22 no.3
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• pp.141-149
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• 2018

Purpose: The purpose of this study is to develop a simple method to measure magnetic susceptibility of arbitrarily shaped materials through MR imaging and numerical modeling. Materials and Methods: Our 3D printed phantom consists of a lower compartment filled with a gel (gel part) and an upper compartment for placing a susceptibility object (object part). The $B_0$ maps of the gel with and without the object were reconstructed from phase images obtained in a 3T MRI scanner. Then, their difference was compared with a numerically modeled $B_0$ map based on the geometry of the object, obtained by a separate MRI scan of the object possibly immersed in an MR-visible liquid. The susceptibility of the object was determined by a least-squares fit. Results: A total of 18 solid and liquid samples were tested, with measured susceptibility values in the range of -12.6 to 28.28 ppm. To confirm accuracy of the method, independently obtained reference values were compared with measured susceptibility when possible. The comparison revealed that our method can determine susceptibility within approximately 5%, likely limited by the object shape modeling error. Conclusion: The proposed gel-phantom-based susceptibility measurement may be used to effectively measure magnetic susceptibility of MR-compatible samples with an arbitrary shape, and can enable development of various MR engineering parts as well as test biological tissue specimens.

• Investigative Magnetic Resonance Imaging
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• v.20 no.3
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• pp.167-174
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• 2016

Purpose: To identify magnetic resonance imaging (MRI) findings of leukemic infiltration of optic nerve and optic neuritis in leukemic patients with emphasis of clinical findings as reference standard to differentiate them. Materials and Methods: MRI and clinical findings of 7 patients diagnosed as leukemic infiltration of optic nerve (n = 5) and optic neuritis (n = 2) in our institution between July 2006 and August 2015were reviewed retrospectively. In particular, MR imaging findings involved perineural enhancement and thickening of optic nerve and its degree, signal intensity, laterality (unilateral/bilateral), intraconal fat infiltration and its degree, and associated central nervous system abnormalities. Results: Of 5 cases of leukemic infiltration of optic nerve, 4 cases showed positive cerebrospinal fluid (CSF) study for leukemia relapse and 1 case was positive on bone marrow (BM) biopsy only. Moreover, of 5 leukemic infiltration of optic nerve, 2 cases showed the most specific MR findings for leukemic central nervous system involvement including 1 prominent leptomeningeal enhancement and 1 chloroma. However, other MR imaging findings of the patients with leukemic infiltration or optic neuritis such as thickening and perineural enhancement of optic nerves are overlapped. Conclusion: Enhancement and thickening of optic nerve were overlapped MR findings in leukemic infiltration of optic nerve and optic neuritis. Our findings suggest that enhancing optic nerve thickening with associated central nervous system MR abnormality favors the diagnosis of leukemic infiltration of optic nerve, especially in patients with history of acute lymphoblastic leukemia. However, CSF and BM study were required for differentiation between leukemic infiltration of optic nerve and optic neuritis.

• Journal of Yeungnam Medical Science
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• v.21 no.2
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• pp.143-150
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• 2004

A thromboembolic stroke is believed to be precipitated by a rupture of vulnerable atheromatous plaques. Until recently the assessment of a further risk of stroke in high-risk patients in whom atherosclerosis has presented with a transient ischaemic attack (TIA), has been confined to a quantitative assessment of the luminal patency of the internal carotid artery. These traditional stratification parameters are no longer believed to be the most accurate predictors of a thrombo-embolism. This is because the process of vessel wall remodeling can maintain a luminal patency, and consequently, quite large friable plaques may remain unidentified. Accordingly, there is a need for an improved risk assessment. The fibrous cap of a vulnerable plaque is thinner, and an intraplaque hemorrhage and inflammation can occur during the development of atherosclerotic plaque. Several imaging methods for identifying vulnerable plaques have been developed. Recently, high resolution magnetic resonance (MR) imaging has emerged as an accurate non-invasive tool that can characterize the carotid plaque components in vivo. A High resolution carotid magnetic resonance is capable of distinguishing an intact, thick fibrous cap from a thin and ruptured cap in carotid plaque. In addition, a plaque MR can identify the active inflammation and detect a hemorrhage. High resolution carotid MR imaging is a valuable noninvasive method for quantifying the plaque components and identifying vulnerable plaque.