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1.
Ann Plast Surg ; 90(1): 33-40, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36534098

ABSTRACT

BACKGROUND: Oncoplastic techniques, in conjunction with lumpectomy and adjuvant radiotherapy, have been demonstrated to achieve good aesthetic results and cancer outcomes in the treatment of patients with macromastia or significant ptosis. This study evaluated a series of patients undergoing breast conservation with concomitant oncoplastic-augmentation-mastopexy and a contralateral augmentation-mastopexy. METHODS: Patients undergoing lumpectomy for breast conservation were identified via a retrospective chart review. Inclusion criteria included patients with ptosis and preexisting breast implants or insufficient breast volume undergoing oncoplastic implant placement/exchange and mastopexy. Demographic characteristics, operative details, and complications were assessed. RESULTS: Thirty-four consecutive patients (64 breasts, 4 unilateral procedures) were included in the study. Average age was 51.4 years, average body mass index was 27, and 38.2% were smokers/former smokers. The average operative time was 2.5 hours. Furthermore, 38.2% of patients received chemotherapy, and 82.4% of patients received breast adjuvant radiotherapy. The average length of follow-up was 11.7 months. In the sample that received radiation, the capsular contracture rate was 25%, with a 7.1% contracture revision rate. For the entire group, a total of 8 patients (23.5%) underwent revisions for either positive margins (8.8%), capsular contracture (8.8%), implant loss (2.9%), or cosmetic concerns (2.9%). One patient developed a pulmonary embolism. CONCLUSIONS: Oncoplastic-augmentation-mastopexy is a safe technique with acceptable complication rates. This technique is best used for breast cancer patients with breast ptosis and a paucity of breast volume or preexisting implants who wish to pursue breast-conserving therapy. The revision rates are acceptable compared with single-stage cosmetic augmentation procedures as well as other oncoplastic techniques described in the literature, but patients must be clearly counseled on contracture risk.


Subject(s)
Breast Implantation , Breast Implants , Breast Neoplasms , Contracture , Mammaplasty , Humans , Middle Aged , Female , Retrospective Studies , Mastectomy, Segmental/adverse effects , Mammaplasty/methods , Breast Implants/adverse effects , Breast Implantation/methods , Breast Neoplasms/surgery , Postoperative Complications/surgery , Contracture/surgery
2.
Ann Surg ; 267(5): 983-988, 2018 05.
Article in English | MEDLINE | ID: mdl-28509699

ABSTRACT

OBJECTIVE: We describe the first successful penis transplant in the United States in a patient with a history of subtotal penectomy for penile cancer. BACKGROUND: Penis transplantation represents a new paradigm in restoring anatomic appearance, urine conduit, and sexual function after genitourinary tissue loss. To date, only 2 penis transplants have been performed worldwide. METHODS: After institutional review board approval, extensive medical, surgical, and radiological evaluations of the patient were performed. His candidacy was reviewed by a multidisciplinary team of surgeons, physicians, psychiatrists, social workers, and nurse coordinators. After appropriate donor identification and recipient induction with antithymocyte globulin, allograft procurement and recipient preparation took place concurrently. Anastomoses of the urethra, corpora, cavernosal and dorsal arteries, dorsal vein, and dorsal nerves were performed, and also inclusion of a donor skin pedicle as the composite allograft. Maintenance immunosuppression consisted of mycophenolate mofetil, tacrolimus, and methylprednisolone. RESULTS: Intraoperative, the allograft had excellent capillary refill and strong Doppler signals after revascularization. Operative reinterventions on postoperative days (PODs) 2 and 13 were required for hematoma evacuation and skin eschar debridement. At 3 weeks, no anastomotic leaks were detected on urethrogram, and the catheter was removed. Steroid resistant-rejection developed on POD 28 (Banff I), progressed by POD 32 (Banff III), and required a repeat course of methylprednisolone and antithymocyte globulin. At 7 months, the patient has recovered partial sensation of the penile shaft and has spontaneous penile tumescence. Our patient reports increased overall health satisfaction, dramatic improvement of self-image, and optimism for the future. CONCLUSIONS: We have shown that it is feasible to perform penile transplantation with excellent results. Furthermore, this experience demonstrates that penile transplantation can be successfully performed with conventional immunosuppression. We propose that our successful penile transplantation pilot experience represents a proof of concept for an evolution in reconstructive transplantation.


Subject(s)
Penile Neoplasms/surgery , Penile Transplantation , Plastic Surgery Procedures/methods , Quality of Life , Urologic Surgical Procedures, Male/methods , Vascularized Composite Allotransplantation/methods , Adult , Computed Tomography Angiography , Follow-Up Studies , Humans , Male , Penile Neoplasms/diagnosis , Pilot Projects , Transplantation, Homologous , Treatment Outcome , Ultrasonography, Doppler
3.
J Vasc Surg ; 65(1): 190-196, 2017 Jan.
Article in English | MEDLINE | ID: mdl-27066947

ABSTRACT

OBJECTIVE: Saphenous vein is the conduit of choice for bypass grafting. Saphenous vein grafts have poor long-term patency rates because of intimal hyperplasia (IH) and subsequent accelerated atherosclerosis. One of the primary triggers of IH is endothelial injury resulting from excessive dilation of the vein after exposure to arterial pressures. Photochemical tissue passivation (PTP) is a technology that cross-links adventitial collagen by a light-activated process, which limits dilation by improving vessel compliance. The objective of this study was to investigate whether PTP limits the development of IH in a rodent venous interposition graft model. METHODS: PTP is accomplished by coating venous adventitia with a photosensitizing dye and exposing it to light. To assess the degree of collagen cross-linking after PTP treatment, a biodegradation assay was performed. Venous interposition grafts were placed in the femoral artery of Sprague-Dawley rats. Rats were euthanized after 4 weeks, and intimal thickness was measured histologically. Vein dilation at the time of the initial procedure was also measured. RESULTS: Time to digestion was 63 ± 7 minutes for controls, 101 ± 2.4 minutes for rose bengal (RB), and 300 ± 0 minutes for PTP (P < .001 PTP vs control). A total of 37 animals underwent the procedure: 12 PTP, 12 RB only, and 13 untreated controls. Dilation of the graft after clamp release was 99% for control, 65% for RB only, and 19% for PTP-treated (P < .001 PTP vs control). Intimal thickness was 77 ± 59 µm in controls, 60 ± 27 µm in RB only, and 33 ± 28 µm in PTP-treated grafts. There was a statistically significant 57% reduction in intimal thickness after treatment with PTP compared with untreated controls (P = .03). CONCLUSIONS: PTP treatment of venous interposition grafts in a rat model resulted in significant collagen cross-linking, decreased vessel compliance, and significant reduction in IH.


Subject(s)
Cross-Linking Reagents/pharmacology , Neointima , Photochemotherapy/methods , Photosensitizing Agents/pharmacology , Rose Bengal/pharmacology , Veins/drug effects , Veins/transplantation , Animals , Collagen/chemistry , Compliance , Dilatation, Pathologic , Femoral Artery/surgery , Hyperplasia , Rats, Sprague-Dawley , Time Factors , Vascular Patency , Veins/chemistry , Veins/pathology
4.
J Am Heart Assoc ; 5(8)2016 07 27.
Article in English | MEDLINE | ID: mdl-27464790

ABSTRACT

BACKGROUND: Bypass grafting remains the standard of care for coronary artery disease and severe lower extremity ischemia. Efficacy is limited by poor long-term venous graft patency secondary to intimal hyperplasia (IH) caused by venous injury upon exposure to arterial pressure. We investigate whether photochemical tissue passivation (PTP) treatment of vein grafts modulates smooth muscle cell (SMC) proliferation and migration, and inhibits development of IH. METHODS AND RESULTS: PTP was performed at increasing fluences up to 120 J/cm(2) on porcine veins. Tensiometry performed to assess vessel elasticity/stiffness showed increased stiffness with increasing fluence until plateauing at 90 J/cm(2) (median, interquartile range [IQR]). At 90 J/cm(2), PTP-treated vessels had a 10-fold greater Young's modulus than untreated controls (954 [IQR, 2217] vs 99 kPa [IQR, 63]; P=0.03). Each pig received a PTP-treated and untreated carotid artery venous interposition graft. At 4-weeks, intimal/medial areas were assessed. PTP reduced the degree of IH by 66% and medial hypertrophy by 49%. Intimal area was 3.91 (IQR, 1.2) and 1.3 mm(2) (IQR, 0.97; P≤0.001) in untreated and PTP-treated grafts, respectively. Medial area was 9.2 (IQR, 3.2) and 4.7 mm(2) (IQR, 2.0; P≤0.001) in untreated and PTP-treated grafts, respectively. Immunohistochemistry was performed to assess alpha-smooth muscle actin (SMA) and proliferating cell nuclear antigen (PCNA). Objectively, there were less SMA-positive cells within the intima/media of PTP-treated vessels than controls. There was an increase in PCNA-positive cells within control vein grafts (18% [IQR, 5.3]) versus PTP-treated vein grafts (5% [IQR, 0.9]; P=0.02). CONCLUSIONS: By strengthening vein grafts, PTP decreases SMC proliferation and migration, thereby reducing IH.


Subject(s)
Photochemotherapy/methods , Tunica Intima/pathology , Animals , Carotid Arteries/drug effects , Elasticity , Graft Survival/physiology , Hyperplasia/prevention & control , Immunohistochemistry , Photosensitizing Agents/pharmacology , Proliferating Cell Nuclear Antigen/metabolism , Rose Bengal/pharmacology , Saphenous Vein/drug effects , Sus scrofa , Swine , Vascular Grafting/methods , Vascular Stiffness/drug effects
5.
J Reconstr Microsurg ; 30(8): 515-22, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25184616

ABSTRACT

BACKGROUND: Free tissue transfer is commonly required for reconstruction of distal third lower extremity injuries. Injuries involving the dorsal surface of the foot require thin pliable flaps. Musculocutaneous flaps are often too bulky to accommodate shoewear. Fasciocutaneous flaps, while an improvement, need secondary contouring procedures. The modified radial forearm fascial flap (MRFFF) may offer an alternative. METHODS: Twelve patients with distal third lower extremity wounds were reconstructed with MRFFF + split thickness skin graft. The modification in flap design leaves fascia radial to the pedicle unharvested, preserving sensibility of the dorsoradial aspect of the hand. Flaps were covered with a skin graft after inset. Donor sites were closed primarily. RESULTS: Nine wounds were traumatic-five with exposed hardware, one burn, one diabetic ulcer, and one wound dehiscence following sarcoma resection + radiation. Out of 12, 11 limbs were salvaged at 1 to 2 years follow-up. All patients ambulated on the reconstructed leg and wore a shoe comfortably. Average time to weight bearing was 2 months. The donor site was limited to 25-cm scar on the volar forearm. No persistent motor/sensory deficits occurred in donor arms. CONCLUSION: MRFFF is an excellent flap for reconstruction of the distal lower extremity. Flap contour allows excellent shoe-fitting without secondary revisions. Replacement of the adipocutaneous flap on MRFFF donor site eliminates the need for a conspicuous donor-site skin graft. The ulnar orientation of the harvested fascia prevents sensory loss in the dorsal hand. The MRFFF provides the ideal replacement of "like with like" for selected distal lower extremity wounds.


Subject(s)
Diabetic Foot/surgery , Free Tissue Flaps/blood supply , Leg Injuries/surgery , Plastic Surgery Procedures , Soft Tissue Injuries/surgery , Adult , Aged , Diabetic Foot/physiopathology , Fascia/blood supply , Fasciotomy , Female , Foot Injuries/surgery , Forearm/blood supply , Forearm/surgery , Humans , Leg Injuries/physiopathology , Male , Middle Aged , Retrospective Studies , Soft Tissue Injuries/physiopathology , Treatment Outcome , Weight-Bearing
7.
Plast Reconstr Surg ; 134(4): 675-683, 2014 Oct.
Article in English | MEDLINE | ID: mdl-24945949

ABSTRACT

BACKGROUND: Centrifugation is a popular processing method, with an unclear mechanism of action. Hypotheses include fat concentration, reduced inflammatory response by removal of blood, and concentration of adipose-derived stem cells. The authors performed multiple experiments to determine the role of centrifugation and compared it with a different processing method (mesh/gauze technique). METHODS: Lipoaspirate components were quantified after centrifugation at increasing speed to determine concentration efficacy. For comparison, the authors quantified the concentration efficacy of mesh/gauze. They also compared the number of adipose-derived stem cells isolated by either method. To determine the effects of each component, they compared fat alone to fat mixed with various spinoff components in a mouse model. They also compared centrifugation to mesh/gauze. RESULTS: The adipocyte fraction remains constant above 5000 g, whereas 1200 g results in 91 percent concentrated fat. Mesh/gauze also results in 90 percent concentrated fat. The number of adipose-derived stem cells in 1 g of fat was 1603 ± 2020 and 1857 ± 1832 in the centrifuge and mesh/gauze groups, respectively (p = 0.86). Five "add-back" groups were created: fat plus oil, fat plus surgical tumescence, fat plus fresh tumescence, fat plus cell pellets and fresh tumescence, and fat plus cell pellets. The fat-only group had better retention than the groups mixed with tumescence, regardless of whether it was surgical, fresh, or had cell pellets. Oil did not affect grafts. Centrifugation at 1200 g was equivalent to mesh/gauze (0.73 ± 0.12 g and 0.72 ± 0.13 g, respectively). CONCLUSIONS: Centrifugation improves graft retention by concentration of the adipocyte fraction. The concentration efficacy of mesh/gauze is equivalent to centrifugation at 1200 g, with equivalent in vivo outcomes.


Subject(s)
Adipocytes/transplantation , Centrifugation/methods , Stem Cell Transplantation , Adult , Animals , Cell Separation/methods , Female , Humans , Mice , Middle Aged
8.
Plast Reconstr Surg ; 133(3): 571-577, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24263392

ABSTRACT

BACKGROUND: Capsular contracture is the most common complication following the insertion of breast implants. Within a decade, half of patients will develop capsular contracture, leading to significant morbidity and need for reoperation. There is no preventative treatment available and the recurrence rate remains high. Photochemical tissue passivation is a novel tissue-stabilization technique that results in collagen cross-linking. It can rapidly link collagen fibers in situ, preserving normal tissue architecture. By using this therapy to passivate the collagenous tissues of the implant pocket, the authors hope to prevent the development of pathogenic collagen bundles and subsequent capsule contracture. METHODS: Six-cubic centimeter tissue expanders were placed below the panniculus carnosus muscle along the dorsum of New Zealand white rabbits. Fibrin glue was instilled into each implant pocket to induce contracture. Treated pockets received photochemical tissue passivation by coating them with a photosensitizing dye and exposing the area to a 532-nm light. After 8 weeks, capsule tissue was harvested for histologic evaluation. RESULTS: Implant capsule thickness is the number one prognostic factor for contracture development. The authors demonstrated a 52 percent decrease in capsule thickness in the passivated group compared with controls. Photochemical tissue passivation resulted in fewer fibrohistiocytic cells and macrophages and in reduced synovial metaplasia and smooth muscle actin deposition. CONCLUSIONS: Photochemical tissue passivation significantly decreased both capsule thickness and smooth muscle actin deposition. It is a promising technique for preventing capsular contracture that can be performed at the time of initial surgery without a significant increase in procedure time.


Subject(s)
Collagen/drug effects , Implant Capsular Contracture/prevention & control , Photochemotherapy , Photosensitizing Agents/pharmacology , Tissue Expansion Devices/adverse effects , Animals , Collagen/metabolism , Disease Models, Animal , Implant Capsular Contracture/etiology , Implant Capsular Contracture/pathology , Photosensitizing Agents/administration & dosage , Rabbits
11.
Arch Surg ; 146(5): 540-3, 2011 May.
Article in English | MEDLINE | ID: mdl-21576608

ABSTRACT

HYPOTHESIS: In the era of modern preoperative staging of patients with rectal cancer, lymph node metastases can be reliably predicted by the histological features of the tumor and preoperative imaging. Local resection can then be safely offered to the patients who are at low risk of having malignant lymph nodes. DESIGN: We reviewed the records of 109 consecutive patients with preoperative imaging results suggestive of T1N0 or T2N0 disease who underwent total mesorectal excision. All patients underwent preoperative endorectal ultrasonography or magnetic resonance imaging and computed tomography, with or without positron emission tomography. Final pathologic investigation identified T3 disease in 27 patients. History, physical examination results, and radiologic and pathologic data were evaluated for predictors of positive nodes in the remaining 82 patients. SETTING: Tertiary care referral center. PATIENTS: Patients with preoperative imaging suggestive of T1N0 or T2N0 rectal cancer. MAIN OUTCOME MEASURES: To evaluate different clinical and pathologic tumor features as predictors of positive lymph nodes in T1 and T2 rectal cancers with negative radiographic nodes. BACKGROUND: Local resection of T1 and T2 rectal cancer results in lower morbidity compared with radical resection. However, recurrence rates after local resection are higher, likely owing to unresected nodal metastasis. Reports on predictors of lymph node metastasis remain inconsistent in the literature. Although local resection may be appropriate for some rectal cancers, selection criteria remain unclear. RESULTS: Despite indications of negative nodes on radiographic examination, 4 of 35 patients with T1 disease (11%) and 13 of 47 with T2 disease (28%) had positive nodes. On univariate analysis, the only significant predictor was depth of invasion: 24 of 65 patients with negative nodes (37%) vs 13 of 17 patients with positive nodes (76%) had tumors invading the lower third of the submucosa and beyond (P = .02). On logistic regression analysis accounting for depth of invasion (lower third of the submucosa and beyond), size, distance from anal verge, differentiation, and lymphovascular and small-vessel invasion, only depth of invasion remained a significant predictor. CONCLUSIONS: In all, 89% of patients with T1 disease (31 of 35) and 72% of those with T2 disease (34 of 47) underwent unnecessary radical resection. Endorectal ultrasonography or magnetic resonance imaging and computed tomography, with or without positron emission tomography, for preoperative staging could not identify these patients reliably. In addition, histologic markers of aggressive disease were not helpful. Thus, local resection for T2 rectal cancer is not justified. Local resection should be offered only to patients with superficial T1 tumors who will adhere to aggressive postoperative surveillance.


Subject(s)
Lymphatic Metastasis/pathology , Microsurgery , Proctoscopy , Rectal Neoplasms/pathology , Rectal Neoplasms/surgery , Rectum/pathology , Rectum/surgery , Adult , Aged , Aged, 80 and over , Diagnostic Imaging , Female , Humans , Intestinal Mucosa/pathology , Logistic Models , Lymph Node Excision , Male , Middle Aged , Neoplasm Invasiveness , Neoplasm Recurrence, Local/mortality , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neoplasm Staging , Prognosis , Rectal Neoplasms/mortality , Survival Analysis , Unnecessary Procedures
12.
J Biomed Opt ; 15(4): 046015, 2010.
Article in English | MEDLINE | ID: mdl-20799817

ABSTRACT

We demonstrate quantitative analysis and error correction of optical coherence tomography (OCT) retinal images by using a custom-built, computer-aided grading methodology. A total of 60 Stratus OCT (Carl Zeiss Meditec, Dublin, California) B-scans collected from ten normal healthy eyes are analyzed by two independent graders. The average retinal thickness per macular region is compared with the automated Stratus OCT results. Intergrader and intragrader reproducibility is calculated by Bland-Altman plots of the mean difference between both gradings and by Pearson correlation coefficients. In addition, the correlation between Stratus OCT and our methodology-derived thickness is also presented. The mean thickness difference between Stratus OCT and our methodology is 6.53 microm and 26.71 microm when using the inner segment/outer segment (IS/OS) junction and outer segment/retinal pigment epithelium (OS/RPE) junction as the outer retinal border, respectively. Overall, the median of the thickness differences as a percentage of the mean thickness is less than 1% and 2% for the intragrader and intergrader reproducibility test, respectively. The measurement accuracy range of the OCT retinal image analysis (OCTRIMA) algorithm is between 0.27 and 1.47 microm and 0.6 and 1.76 microm for the intragrader and intergrader reproducibility tests, respectively. Pearson correlation coefficients demonstrate R(2)>0.98 for all Early Treatment Diabetic Retinopathy Study (ETDRS) regions. Our methodology facilitates a more robust and localized quantification of the retinal structure in normal healthy controls and patients with clinically significant intraretinal features.


Subject(s)
Algorithms , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Pattern Recognition, Automated/methods , Retina/anatomy & histology , Retinoscopy/methods , Tomography, Optical Coherence/methods , Artificial Intelligence , Humans , Reproducibility of Results , Sensitivity and Specificity
13.
Surg Obes Relat Dis ; 5(4): 455-8, 2009.
Article in English | MEDLINE | ID: mdl-19136311

ABSTRACT

BACKGROUND: Silastic ring vertical gastric bypass (SRVGB) with jejunal interposition is our standard operation for morbidly obese patients. We present the results of 5 years of follow-up in a cohort of patients who underwent SRVGB in 2001. METHODS: The records of all 160 consecutive patients who underwent SRVGB from January to December 2001 were reviewed. Of the 160 procedures, 143 were primary open cases, 14 were revisions from restrictive procedures, and 3 were laparoscopic cases. At 5 years, the body mass index and percentage of excess weight loss was available for 133 patients (83%) at office visits (n = 91, 68.4%), by telephone (n = 40, 30.1%), or by e-mail (n = 2, 1.5%). RESULTS: Of the 160 patients, 121 were women and 39 were men, with a mean age of 33.15 +/- 10.0 years, percentage of ideal body weight of 195.7% +/- 40.8%, and body mass index of 44.6 +/- 9.3 kg/m(2). The mean hospital stay was 3 +/- 1 days. One patient (.6%) died of a pulmonary embolus. Early complications included 3 cases (1.87%) of upper gastrointestinal bleeding and 4 gastric leaks (2.5%): 2 (1.36%) from primary cases and 2 (14.29%) from revisional cases. Late complications included 32 patients (20%) with incisional hernias, 20 (12.5%) with anemia, 14 (8.8%) with dumping, 4 (2.5%) with gastrojejunal stricture, 2 (1.25%) with intestinal obstruction, and 2 (1.25%) requiring silastic ring surgical removal. The 5-year follow-up data were available for 133 patients (83%). The mean body mass index in this group was 27 +/- 5 kg/m(2), with a percentage of excess weight loss of 83% +/- 18.3% at 5 years postoperatively. CONCLUSION: The results of our study have shown that SRVGB is an effective operation for promoting lasting weight loss, with acceptable mortality and complication rates.


Subject(s)
Dimethylpolysiloxanes/therapeutic use , Gastric Bypass/instrumentation , Gastroplasty/instrumentation , Obesity, Morbid/surgery , Adult , Body Mass Index , Cohort Studies , Female , Humans , Male , Retrospective Studies , Time Factors , Treatment Outcome , Weight Loss , Young Adult
14.
J Biomed Opt ; 12(4): 041209, 2007.
Article in English | MEDLINE | ID: mdl-17867798

ABSTRACT

The development of improved segmentation algorithms for more consistently accurate detection of retinal boundaries is a potentially useful solution to the limitations of existing optical coherence tomography (OCT) software. We modeled artifacts related to operator errors that may normally occur during OCT imaging and evaluated their influence on segmentation results using a novel segmentation algorithm. These artifacts included: defocusing, depolarization, decentration, and a combination of defocusing and depolarization. Mean relative reflectance and average thickness of the automatically extracted intraretinal layers was then measured. Our results show that defocusing and depolarization errors together have the greatest altering effect on all measurements and on segmentation accuracy. A marked decrease in mean relative reflectance and average thickness was observed due to depolarization artifact in all intraretinal layers, while defocus resulted in a less-marked decrease. Decentration resulted in a marked but not significant change in average thickness. Our study demonstrates that care must be taken for good-quality imaging when measurements of intraretinal layers using the novel algorithm are planned in future studies. An awareness of these pitfalls and their possible solutions is crucial for obtaining a better quantitative analysis of clinically relevant features of retinal pathology.


Subject(s)
Algorithms , Image Interpretation, Computer-Assisted/methods , Information Storage and Retrieval/methods , Pattern Recognition, Automated/methods , Retina/anatomy & histology , Retinoscopy/methods , Tomography, Optical Coherence/methods , Adult , Feasibility Studies , Female , Humans , Image Enhancement/methods , Male , Reproducibility of Results , Sensitivity and Specificity
15.
IEEE Trans Med Imaging ; 26(6): 761-71, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17679327

ABSTRACT

A comparison between two nonlinear diffusion methods for denoising OCT images is performed. Specifically, we compare and contrast the performance of the traditional nonlinear Perona-Malik filter with a complex diffusion filter that has been recently introduced by Gilboa et al.. The complex diffusion approach based on the generalization of the nonlinear scale space to the complex domain by combining the diffusion and the free Schridinger equation is evaluated on synthetic images and also on representative OCT images at various noise levels. The performance improvement over the traditional nonlinear Perona-Malik filter is quantified in terms of noise suppression, image structural preservation and visual quality. An average signal-to-noise ratio (SNR) improvement of about 2.5 times and an average contrast to noise ratio (CNR) improvement of 49% was obtained while mean structure similarity (MSSIM) was practically not degraded after denoising. The nonlinear complex diffusion filtering can be applied with success to many OCT imaging applications. In summary, the numerical values of the image quality metrics along with the qualitative analysis results indicated the good feature preservation performance of the complex diffusion process, as desired for better diagnosis in medical imaging processing.


Subject(s)
Algorithms , Artifacts , Image Enhancement/methods , Image Interpretation, Computer-Assisted/methods , Models, Biological , Tomography, Optical Coherence/instrumentation , Computer Simulation , Nonlinear Dynamics , Phantoms, Imaging , Reproducibility of Results , Sensitivity and Specificity , Tomography, Optical Coherence/methods
16.
Opt Express ; 13(25): 10200-16, 2005 Dec 12.
Article in English | MEDLINE | ID: mdl-19503235

ABSTRACT

Segmentation of retinal layers from OCT images is fundamental to diagnose the progress of retinal diseases. In this study we show that the retinal layers can be automatically and/or interactively located with good accuracy with the aid of local coherence information of the retinal structure. OCT images are processed using the ideas of texture analysis by means of the structure tensor combined with complex diffusion filtering. Experimental results indicate that our proposed novel approach has good performance in speckle noise removal, enhancement and segmentation of the various cellular layers of the retina using the STRATUSOCTTM system.

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