1.Image Denoising for Metal MRI Exploiting Sparsity and Low Rank Priors.
Sangcheon CHOI ; Jun Sik PARK ; Hahnsung KIM ; Jaeseok PARK
Investigative Magnetic Resonance Imaging 2016;20(4):215-223
PURPOSE: The management of metal-induced field inhomogeneities is one of the major concerns of distortion-free magnetic resonance images near metallic implants. The recently proposed method called “Slice Encoding for Metal Artifact Correction (SEMAC)” is an effective spin echo pulse sequence of magnetic resonance imaging (MRI) near metallic implants. However, as SEMAC uses the noisy resolved data elements, SEMAC images can have a major problem for improving the signal-to-noise ratio (SNR) without compromising the correction of metal artifacts. To address that issue, this paper presents a novel reconstruction technique for providing an improvement of the SNR in SEMAC images without sacrificing the correction of metal artifacts. MATERIALS AND METHODS: Low-rank approximation in each coil image is first performed to suppress the noise in the slice direction, because the signal is highly correlated between SEMAC-encoded slices. Secondly, SEMAC images are reconstructed by the best linear unbiased estimator (BLUE), also known as Gauss-Markov or weighted least squares. Noise levels and correlation in the receiver channels are considered for the sake of SNR optimization. To this end, since distorted excitation profiles are sparse, l1 minimization performs well in recovering the sparse distorted excitation profiles and the sparse modeling of our approach offers excellent correction of metal-induced distortions. RESULTS: Three images reconstructed using SEMAC, SEMAC with the conventional two-step noise reduction, and the proposed image denoising for metal MRI exploiting sparsity and low rank approximation algorithm were compared. The proposed algorithm outperformed two methods and produced 119% SNR better than SEMAC and 89% SNR better than SEMAC with the conventional two-step noise reduction. CONCLUSION: We successfully demonstrated that the proposed, novel algorithm for SEMAC, if compared with conventional de-noising methods, substantially improves SNR and reduces artifacts.
Artifacts
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Least-Squares Analysis
;
Magnetic Resonance Imaging*
;
Methods
;
Noise
;
Signal-To-Noise Ratio
2.A Comparative Study Between Newly Developed Wave-form and Traditional Straight-form Splints.
Sehui KIM ; Woochan JEON ; Jisook LEE ; Choung Ah LEE ; Sangcheon CHOI ; Yoonseok JUNG ; Giwoon KIM ; Won Gabriel CHUNG
Journal of the Korean Society of Emergency Medicine 2012;23(6):869-873
PURPOSE: Widely used fiberglass splints are made from straight-form material. These prove difficult to mold at joints and form wrinkles, causing complications such as pain, pressure sores, and peripheral nerve palsy. We compared the usefulness of wave-form splints with straight-form splints and the level of satisfaction of these designs from care providers and wearers. METHODS: Eighty-nine (n=89) emergency physicians and orthopedic surgeons participated in this study. The subjects (acting as care providers and mock patients) used wave-form and straight-form material to construct and wear short leg splints, long arm splints, and sugar tong splints. The clinicians were surveyed on their satisfaction as providers and wearers. All questions were measured on scores from 0 and 10(10=maximum score). After splints were removed, subjects were surveyed on the extent of splint wrinkling with scores from 1 to 3(3=maximum wrinkling). RESULTS: Provider satisfaction scores for wave-form splints versus straight-form splints in short leg splint applications were 7.76+/-1.30 vs 6.74+/-1.25 (p=0.000). Provider satisfaction scores for wave-form splints versus straight-form splints in long arm splint applications were 7.73+/-1.33 and 6.73+/-1.59 (p=0.004), respectively. The subjects felt more comfortable wearing wave-form splints, compared to straight-form splints (7.79+/-1.49 vs. 6.79+/-1.58, respectively; p=0.004) and more satisfied (8.03+/-1.35 vs. 7.18+/-1.33, respectively; p=0.003). The frequencies of wrinkle occurrence in wave-form and straight-form splints were 29.7% and 42.2%, respectively (p=0.02). CONCLUSION: Wave-form splints may be more practical for molding and wearing than traditional straight-form splints.
Arm
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Casts, Surgical
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Emergencies
;
Fungi
;
Glass
;
Immobilization
;
Joints
;
Leg
;
Orthopedics
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Paralysis
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Peripheral Nerves
;
Pressure Ulcer
;
Splints
3.Clinical applications and contemporary trends of hyperbaric oxygen therapy in Korea.
Yeon Ho YOU ; Heeduck KIM ; Hyun KIM ; Sangcheon CHOI ; Giwoon KIM
Journal of the Korean Medical Association 2014;57(7):601-606
Hyperbaric oxygen therapy (HBOT) is approved in the United States for 14 accepted indications, which are approved by the HBOT committee of the Undersea and Hyperbaric Medical Society and by the Food and Drug Administration. These indications are also used worldwide. HBOT is a mode of medical treatment in which the patient is situated in an enclosed pressure chamber and breathes 100% oxygen at a pressure greater than 1 atmosphere absolute (ATA), with the usual therapeutic pressure set at greater than 1.4 ATA. In South Korea, an expanded knowledge base and formalized education in HBOT do not exist, and numerous HBOT devices are old and nearing the cessation of operation, although HBOT has undergone refinement, with an increased understanding of mechanisms of action and clinical applications. Furthermore, there is no specific board certification of HBO competence for emergency, critical care, and surgical physicians and technicians in South Korea. We summarize the existing literature on the uses of HBO with the aim of enhancing the understanding of this therapeutic technique.
Atmosphere
;
Certification
;
Critical Care
;
Education
;
Emergencies
;
Humans
;
Hyperbaric Oxygenation*
;
Knowledge Bases
;
Korea
;
Mental Competency
;
Oxygen
;
Societies, Medical
;
United States
;
United States Food and Drug Administration
4.Assessment and Methods of Nutritional Support during Atropinization in Organophosphate and Carbamate Poisoning Cases
Jong-uk PARK ; Young-gi MIN ; Sangcheon CHOI ; Dong-wan KO ; Eun Jung PARK
Journal of The Korean Society of Clinical Toxicology 2020;18(2):123-129
Purpose:
Atropine is an antidote used to relieve muscarinic symptoms in patients with organophosphate and carbamate poisoning. Nutritional support via the enteral nutrition (EN) route might be associated with improved clinical outcomes in critically ill patients. This study examined the administration of nutritional support in patients undergoing atropinization, including methods of supply, outcomes, and complications.
Methods:
A retrospective observational study was conducted in a tertiary care teaching hospital from 2010 to 2018. Forty-five patients, who were administered with atropine and on mechanical ventilation (MV) due to organophosphate or carbamate poisoning, were enrolled.
Results:
Nutritional support was initiated on the third day of hospitalization. Thirty-three patients (73.3%) were initially supported using parenteral nutrition (PN). During atropinization, 32 patients (71.1%) received nutritional support via EN (9) or PN (23). There was no obvious reason for not starting EN during atropinization (61.1%). Pneumonia was observed in both patient groups on EN and PN (p=0.049). Patients without nutritional support had a shorter MV duration (p=0.034) than patients with nutritional support.The methods of nutritional support during atropinization did not show differences in the number of hospital days (p=0.711), MV duration (p=0.933), duration of ICU stay (p=0.850), or recovery at discharge (p=0.197).
Conclusion
Most patients undergoing atropinization were administered PN without obvious reasons to preclude EN. Nutritional support was not correlated with the treatment outcomes or pneumonia. From these results, it might be possible to choose EN in patients undergoing atropinization, but further studies will be necessary.
5.Assessment and Methods of Nutritional Support during Atropinization in Organophosphate and Carbamate Poisoning Cases
Jong-uk PARK ; Young-gi MIN ; Sangcheon CHOI ; Dong-wan KO ; Eun Jung PARK
Journal of The Korean Society of Clinical Toxicology 2020;18(2):123-129
Purpose:
Atropine is an antidote used to relieve muscarinic symptoms in patients with organophosphate and carbamate poisoning. Nutritional support via the enteral nutrition (EN) route might be associated with improved clinical outcomes in critically ill patients. This study examined the administration of nutritional support in patients undergoing atropinization, including methods of supply, outcomes, and complications.
Methods:
A retrospective observational study was conducted in a tertiary care teaching hospital from 2010 to 2018. Forty-five patients, who were administered with atropine and on mechanical ventilation (MV) due to organophosphate or carbamate poisoning, were enrolled.
Results:
Nutritional support was initiated on the third day of hospitalization. Thirty-three patients (73.3%) were initially supported using parenteral nutrition (PN). During atropinization, 32 patients (71.1%) received nutritional support via EN (9) or PN (23). There was no obvious reason for not starting EN during atropinization (61.1%). Pneumonia was observed in both patient groups on EN and PN (p=0.049). Patients without nutritional support had a shorter MV duration (p=0.034) than patients with nutritional support.The methods of nutritional support during atropinization did not show differences in the number of hospital days (p=0.711), MV duration (p=0.933), duration of ICU stay (p=0.850), or recovery at discharge (p=0.197).
Conclusion
Most patients undergoing atropinization were administered PN without obvious reasons to preclude EN. Nutritional support was not correlated with the treatment outcomes or pneumonia. From these results, it might be possible to choose EN in patients undergoing atropinization, but further studies will be necessary.
6.Assessment of early nutritional state in critical patients with intoxication and the effect of nutritional status on prognosis
Dong-wan KO ; Sangcheon CHOI ; Young-gi MIN ; Hyuk jin LEE ; Eun Jung PARK
Journal of The Korean Society of Clinical Toxicology 2021;19(2):93-99
Purpose:
Nutritional status and support in critically ill patients are important factors in determining patient recovery and prognosis.The aim of this study was to analyze the early nutritional status and the methods of nutritional support in critically ill patients with acute poisoning and to evaluate the effect of nutritional status on prognosis.
Methods:
A retrospective study was conducted in tertiary care teaching hospital from January 2018 to December 2020. in an emergency department of university hospital, 220 patients who were stayed more than 2 days of poisoning in intensive care unit were enrolled.
Results:
155 (70.5%) of patients with acute poisoning had low-risk in nutritional risk screening (NRS). Patients with malignancy had higher NRS (low risk 5.2%, moderate risk 18.5%, high risk 13.2%, p=0.024). Patients of 91.4% supplied nutrition via oral route or enteral route. Parenteral route for starting method of nutritional support were higher in patients with acute poisoning of herbicide or pesticide (medicine 3.2%, herbicide 13.8%, pesticide 22.2%, p=0.000). In multivariate logistic regression analysis, herbicide or pesticide intoxication, higher risk in NRS and sequential organ failure assessment over 4.5 were affecting factor on poor recovery at discharge.
Conclusion
NRS in patients intoxicated with herbicide or pesticide were higher than that in patients intoxicated with medicine intoxication. Enteral nutrition in patients intoxicated with herbicide or pesticide was less common. Initial NRS was correlated with recovery at discharge in patient with intoxication. It is expected to be helpful in finding patients with high-risk nutritional status in acute poisoning patients and establishing a treatment plan that can actively implement nutritional support.