• 대한의용생체공학회:의공학회지
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• 제19권3호
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• pp.243-250
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• 1998

초고속 자기공명 영상 기법의 일종인 나선 주사 영상의 재구성을 위하여 k-공간에서 극좌표와 직각 좌표계를 기초로한 재구성방법들을 분석하였다. 나선 주사 영상의 재구성은 나선 궤적상에서 측정된 데이터를 극좌표나 직각 좌표계로 변환시키기 위하여 보간 기술들이 사용된다. 나선주사 영상의 다양한 재구성 알고리즘들을 시험하여 보았고, 재구성된 영상의 질을 비교하였다. 본 연구진이 제안한 투영 영역에서 dc-offset보정을 한 향상된 재구성 알고리즘이 시뮬레이션을 통하여 가장 우수한 것으로 나타났다. 또한, 기존의 재구성 방법들에서 나타났던 영상 artifact도 제안된 방법에서는 완전히 사라짐을 확인할 수 있었다.

• Molecules and Cells
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• 제22권2호
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• pp.154-162
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• 2006

The entire gene cluster involved in the biosynthesis of angucyclines Sch 47554 and Sch 47555 was cloned, sequenced, and characterized. Analysis of the nucleotide sequence of genomic DNA spanning 77.5-kb revealed a total of 55 open reading frames, and the deduced products exhibited strong sequence similarities to type II polyketide synthases, deoxysugar biosynthetic enzymes, and a variety of accessory enzymes. The involvement of this gene cluster in the pathway of Sch 47554 and Sch 47555 was confirmed by genetic inactivation of the aromatase, including a portion of the ketoreductase, which was disrupted by inserting the thiostrepton gene.

• Archives of Plastic Surgery
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• 제48권4호
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• pp.410-416
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• 2021

Background This systematic review compared free anterolateral thigh (ALT) flaps versus pedicled distally based sural artery (DBSA) flaps for reconstruction of soft tissue defects of dorsal foot and ankle in children. Methods A systematic literature search was performed to identify cases where an ALT or DBSA was used to reconstruct the dorsal foot in children. A total of 19 articles were included in the systematic review. Results Eighty-three patients underwent an ALT reconstruction and 138 patients underwent a DBSA reconstruction. Patients who had a DBSA were more likely to require grafting of the donor site (P<0.001). The size of ALT flaps was significantly larger than DBSA flaps (P=0.002). Subsequent flap thinning was required in 30% of patients after ALT and 12% of patients after DBSA reconstruction (P<0.001). Complications occurred in 11.6% of DBSA and 8.4% of ALT flaps (8.4%). Conclusions Both flaps are valid options in reconstructing pediatric foot and ankle defects. Each flap has advantages and disadvantages as discussed in this review article. In general for larger defects, an ALT flap was used. Flap choice should be based on the size of the defect.

• Journal of Trauma and Injury
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• 제32권3호
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• pp.187-193
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• 2019

Many techniques have been developed for reconstruction of the hand; however, less attention has been paid to foot reconstruction techniques. In particular, reconstruction of the forefoot and big toe has been considered a minor procedure despite the importance of these body parts for standing and walking. Most of the weight load on the foot is concentrated on the forefoot and big toe, whereas the other toes have a minor role in weight bearing. Moreover, the forefoot and big toe are important for maintaining balance and supporting the body when changing directions. Recently, attention has been focused on the aesthetic appearance and functional aspects of the body, which are important considerations in the field of reconstructive surgery. In patients for whom flap reconstruction in the forefoot and big toe is planned, clinicians should pay close attention to flap survival as well as functional and cosmetic outcomes of surgery. In particular, it is important to assess the ability of the flap to withstand functional weight bearing and maintain sufficient durability under shearing force. Recovery of protective sensation in the forefoot area can reduce the risk of flap loss and promote rapid rehabilitation and functional recovery. Here, we report our experience with two cases of successful reconstruction of the forefoot and big toe with a sensate anterolateral thigh flap, with a review of the relevant literature.

• 대한두개안면성형외과학회지
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• 제23권3호
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• pp.95-102
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• 2022

The challenges of successful nasal reconstruction, which are related to the anatomical complexity of the region, have been extensively studied. Revisional operations are often required to achieve proper nasal reconstruction, with results resembling the premorbid nasal status. This is necessary to ensure the quality of life of skin cancer patients. Fundamental nasal reconstruction requires both proper soft tissue coverage and proper function. However, earlier studies in the field primarily focused on the functional aspect of nose reconstruction, although the cosmetic aspect is also an important factor to consider. In response to this need, many recent studies on nose reconstruction have proposed various refinement strategies to improve aesthetic satisfaction. Most plastic surgeons accept the nasal aesthetic subunit principle as a standard for nasal reconstruction. This review outlines the commonly used surgical refinement options and management strategies for postoperative complications based on the subunit principle. In patients with nasal defects, a proper technical strategy might help minimize revision operations and optimize the long-term results.

• Archives of Plastic Surgery
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• 제49권3호
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• pp.339-345
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• 2022

Background Patients that undergo mastectomy for breast cancer with reconstruction may be prone to prolonged opioid use. As risk factors are not well-established, this article sought to better understand the risk factors that may be associated with this. Methods Patients that underwent breast reconstruction between 2010 and 2018 were identified in PearlDiver, a national insurance claims database. Patient demographics and comorbidities were elucidated, and various complications were then identified. Descriptive statistics as well as a multivariate analysis was used to evaluate the association of risk factors and complications. Results Breast reconstruction patients of 24,765 were identified from this database. Obesity, tobacco use, benzodiazepine use, and anticonvulsant use were all associated with prolonged opioid prescriptions greater than 90 days after both alloplastic and autologous reconstruction. Conclusion Prolonged opioid use continues to remain a topic of concern, and particularly in cancer patients that undergo breast reconstruction. Providers should be aware of potential risk factors for this to reduce this chance following breast reconstruction surgery.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.293-299
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• 2021

Purpose: To accelerate magnetic resonance fingerprinting (MRF) by developing a flexible deep learning reconstruction method. Materials and Methods: Synthetic data were used to train a deep learning model. The trained model was then applied to MRF for different organs and diseases. Iterative reconstruction was performed outside the deep learning model, allowing a changeable encoding matrix, i.e., with flexibility of choice for image resolution, radiofrequency coil, k-space trajectory, and undersampling mask. In vivo experiments were performed on normal brain and prostate cancer volunteers to demonstrate the model performance and generalizability. Results: In 400-dynamics brain MRF, direct nonuniform Fourier transform caused a slight increase of random fluctuations on the T2 map. These fluctuations were reduced with the proposed method. In prostate MRF, the proposed method suppressed fluctuations on both T1 and T2 maps. Conclusion: The deep learning and iterative MRF reconstruction method described in this study was flexible with different acquisition settings such as radiofrequency coils. It is generalizable for different in vivo applications.

• Archives of Plastic Surgery
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• 제49권3호
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• pp.448-452
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• 2022

Total reconstruction of the penis (TPR) represents a challenge for urologists and plastic surgeons, especially when urethral length is severely reduced. We here describe, for the first time in an oncologic scenario, a double flap phalloplasty using a pedicled anterolateral thigh (ALT) flap for penile reconstruction and a radial forearm free flap (RFFF) for complete neourethra and glans reconstruction following penile amputation. A 48-year-old patient came to our department following a total penectomy with inferior urethral derivation. The indication for a double flap phalloplasty was posed as only way to fully reconstruct the urethra on its length avoiding possible complications of single flap reconstruction using tube-into-tube technique. Both flaps healed uneventfully with no neourethral strictures or fistulas described. At 18 months follow-up, the patient was extremely satisfied with the aesthetic result and was able to void in standing position. We think that a double free tissue transfer for TPR should be considered, particularly when a urethral length > 14 cm needs to be reconstructed. While the pedicled ALT can be used to reconstruct a proper penile shaft with an easily concealed scar, the RFFF can provide adequate neourethra length with satisfactory sensory recovery at the neoglans.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.764-768
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• 2022

The wrap-around flap (WAF) has become a popular approach to thumb reconstruction because the results are functionally and cosmetically excellent. By modifying to a partial toenail transfer, the WAF can also be used for finger reconstruction. However, performing cosmetically superior finger reconstruction is a significant challenge because it is difficult to reconstruct the natural nailfold by partial nail transplantation, although partial nail transplantation is required to reconstruct a narrow fingernail. One side of the reconstructed lateral nailfold tends to be a missing nail margin, and one side of the proximal nailfold angle tends to be retracted. Based on the rationale that loss of the lateral nailfold volume due to the postoperative tension of the volar flap would result in a missing nail margin, the volume of the lateral nailfold was maintained with a single thread that was passed from the nail to the volar flap. Additionally, half of the proximal nailfold from the nail plate was elevated to advance it forward. The results indicated that a cosmetically natural nailfold was achieved with the WAF approach to finger reconstruction. These easy and simple techniques enable reconstruction of a cosmetically natural nailfold using WAF for finger reconstruction.

• Archives of Plastic Surgery
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• 제49권1호
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• pp.91-98
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• 2022

Background Predicting the need for post-traumatic reconstruction of lower extremity injuries remains a challenge. Due to the larger volume of cases in adults than in children, the majority of the medical literature has focused on adult lower extremity reconstruction. This study evaluates predictive risk factors associated with the need for free flap reconstruction in pediatric patients following lower extremity trauma. Methods An IRB-approved retrospective chart analysis over a 5-year period (January 1, 2012 to December 31, 2017) was performed, including all pediatric patients (<18 years old) diagnosed with one or more lower extremity wounds. Patient demographics, trauma information, and operative information were reviewed. The statistical analysis consisted of univariate and multivariate regression models to identify predictor variables associated with free flap reconstruction. Results In total, 1,821 patients were identified who fit our search criteria, of whom 41 patients (2.25%) required free flap reconstruction, 65 patients (3.57%) required local flap reconstruction, and 19 patients (1.04%) required skin graft reconstruction. We determined that older age (odds ratio [OR], 1.134; P =0.002), all-terrain vehicle accidents (OR, 6.698; P<0.001), and trauma team activation (OR, 2.443; P=0.034) were associated with the need for free flap reconstruction following lower extremity trauma in our pediatric population. Conclusions Our study demonstrates a higher likelihood of free flap reconstruction in older pediatric patients, those involved in all-terrain vehicle accidents, and cases involving activation of the trauma team. This information can be implemented to help develop an early risk calculator that defines the need for complex lower extremity reconstruction in the pediatric population.