The scale of local structure is a key parameter in medical image registration. Unfortunately, no much attention has been paid to the scale selection for the local structures in the images. This paper proposes a data-driven scale selection method for local structures in the image. By using minimal description length criterion to maximize the posterior probability of local structure region with coherence constraint based on the Markov random field model, an optimal scale for each local structure, which is segmented with super-pixel representation, is assigned in terms of variance in a discrete anisotropic scale space. Therefore, the local structure's scale can be selected for further non-rigid medical image registration.
Algorithms ; Image Enhancement ; methods ; Image Processing, Computer-Assisted ; methods

We applied two classical algorithms in hyperspectral imaging to extract endmember for biological fluorescence imaging. A combined algorithm was found to initialize the PPI with decreasing the number of multi-spectral pixels, with subsequent N-FINDR refinement, which could make a better result.
Algorithms ; Biology ; methods ; Diagnostic Imaging ; methods ; Image Interpretation, Computer-Assisted ; methods ; Microscopy, Fluorescence ; methods ; Spectrometry, Fluorescence ; methods

An effective MR and PET image registration method designed for clinical use is given in this paper. A new correlation ratio similarity measure for voxel intensity based medical image registration was adopted. Detailed discussion on methods of rigid transformation, resampling, multi-resolution medical image representation and optimization for accelerated multi-resolution registration scheme is also given in this paper. At last, experimental results based on clinical MR and PET medical images show that correlation ratio based multi-resolution registration method works well and is faster than most existing direct voxel intensity based registration methods under clinical scenario.
Algorithms ; Humans ; Image Processing, Computer-Assisted ; methods ; Magnetic Resonance Imaging ; Models, Statistical ; Tomography, Emission-Computed, Single-Photon

The scale of local structure is a key parameter in medical image registration. Unfortunately, no much attention has been paid to the scale selection for the local structures in the images. This paper proposes a data-driven scale selection method for local structures in the image. By using minimal description length criterion to maximize the posterior probability of local structure region with coherence constraint based on the Markov random field model, an optimal scale for each local structure, which is segmented with super-pixel representation, is assigned in terms of variance in a discrete anisotropic scale space. Therefore, the local structure’s scale can be selected for further non-rigid medical image registration.

The problem of Poisson denoising is common in various photon-limited imaging applications, especialy in low-light imaging, astronomy and nuclear medical applications. Due to the smal sample problem and the related insufficient self-similarity between patches of whole image, many denoising algorithms cannot obtain the favorable denoising performance. We propose patch-order resampling PCA algorithm for Poisson noise reduction. Firstly, we use the patch-ordered operations to sort the extracted image patches and exploit the bootstrap resampling method to resample the different blocks of spectral images to obtain more data matrix of image samples. Then, we select the patches with largest weights corresponding to the vectors of image samples data matrix as the most similar patches. Finaly, we use principal component analysis algorithm for processing the image to obtain the final denoised image. Experiments results show that the proposed method achieves excelent Poisson noise removal performance in the photon-limited images with smal sample problems.

Chronic radiation enteropathy(CRE) represents a latent intestinal injury resulting from abdominal-pelvic radiotherapy. Severe complications like refractory bleeding, intestinal obstruction, perforation and fistula may occur during CRE progression. Surgical treatment is the most effective way to handle these complications. Since radiotherapy has become an important and common way to relieve or even cure many malignant tumors, the incidence of severe complications of CRE is likely to rise. Thus the value of surgical treatment in managing severe complications of CRE should gain more attention. Through the literature review combined with our clinical experience, this paper analyzes the preoperative management and surgical treatment of five long-term complications of CRE, including obstruction, enteric fistula, rectovaginal fistula, perforation and bleeding. Also we propose that when managing patients with severe complications of CRE, clinicians should carefully master the surgical indications, consummate perioperative management, design personal surgical plan according to patient's condition and make improving the quality of life of patients the ultimate purpose of surgical treatment for CRE while assuring its safety.

Objective: To investigate the safety and efficacy of surgical treatment for chronic radiation intestinal injury. Methods: A descriptive cohort study was performed. Clinical data of 73 patients with definite radiation history and diagnosed clinically as chronic radiation intestinal injury, undergoing operation at Department of Colorectal Surgery, the Sixth Affiliated Hospital of Sun Yat-sen University from January 1, 2012 to February 28, 2019, were reviewed and analyzed retrospectively. Patients did not undergo operation or only received adhesiolysis were excluded. All the patients had preoperative examination and overall evaluation of the disease. According to severity of intestinal obstruction and patients′ diet, corresponding nutritional support and conservative treatment were given. Surgical methods: The one-stage bowel resection and anastomosis was the first choice for surgical treatment of chronic radiation intestinal injury. Patients with poor nutritional condition were given enterostomy and postoperative enteral nutrition and second-stage stoma closure and intestinal anastomosis if nutritional condition improved. For those who were unable to perform stoma closure, a permanent stoma should be performed. Patients with severe abdominal adhesion which was difficult to separate, enterostomy or bypass surgery after adhesiolysis would be the surgical choice. For patients with tumor metastasis or recurrence, enterostomy or bypass surgery should be selected. Observation parameters: the overall and major (Clavien-Dindo grades III to V) postoperative complication within 30 days after surgery or during hospitalization; mortality within postoperative 30 days; postoperative hospital stay; time to postoperative recovery of enteral nutrition; time to removal of drainage tube. Results: Of the 73 patients who had been enrolled in this study, 10 were male and 63 were female with median age of 54 (range, 34-80) years. Preoperative evaluation showed that 61 patients had intestinal stenosis, 63 had intestinal obstruction, 11 had intestinal perforation, 20 had intestinal fistula, 3 had intestinal bleeding, and 6 had abdominal abscess, of whom 64(87.7%) patients had multiple complications. Tumor recurrence or metastasis was found in 15 patients. A total of 65(89.0%) patients received preoperative nutritional support, of whom 35 received total parenteral nutrition and 30 received partial parenteral nutrition. The median preoperative nutritional support duration was 8.5 (range, 6.0-16.2) days. The rate of one-stage intestine resection was 69.9% (51/73), and one-stage enterostomy was 23.3% (17/73). In the 51 patients undergoing bowel resection, the average length of resected bowel was (50.3±49.1) cm. Among the 45 patients with intestinal anastomosis, 4 underwent manual anastomosis and 41 underwent stapled anastomosis; 36 underwent side-to-side anastomosis, 5 underwent end-to-side anastomosis, and 4 underwent end-to-end anastomosis. Eighty postoperative complications occurred in 39 patients and the overall postoperative complication rate was 53.4% (39/73), including 39 moderate to severe complications (Clavien-Dindo grade III-V) in 20 patients (27.4%, 20/73) and postoperative anastomotic leakage in 2 patients (2.7%, 2/73). The mortality within postoperative 30 days was 2.7% (2/73); both patients died of abdominal infection, septic shock, and multiple organ failure caused by anastomotic leakage. The median postoperative hospital stay was 13 (11, 23) days, the postoperative enteral nutrition time was (7.2±6.9) days and the postoperative drainage tube removal time was (6.3±4.2) days. Conclusions Surgical treatment, especially one-stage anastomosis, is safe and feasible for chronic radiation intestine injury. Defining the extent of bowel resection, rational selection of the anatomic position of the anastomosis and perioperative nutritional support treatment are the key to reduce postoperative complications.

Objective:To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury.Methods:This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded.Results:The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100–6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions:TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.

Objective:To investigate the safety and efficacy of total pelvic exenteration (TPE) for treating late complications of radiation-induced pelvic injury.Methods:This was a descriptive case series study. The inclusion criteria were as follows: (1) confirmed radiation-induced pelvic injury after radiotherapy for pelvic malignancies; (2) late complications of radiation-induced pelvic injury, such as bleeding, perforation, fistula, and obstruction, involving multiple pelvic organs; (3) TPE recommended by a multidisciplinary team; (4) patient in good preoperative condition and considered fit enough to tolerate TPE; and (5) patient extremely willing to undergo the procedure and accept the associated risks. The exclusion criteria were as follows: (1) preoperative or intraoperative diagnosis of tumor recurrence or metastasis; (2) had only undergone diversion or bypass surgery after laparoscopic exploration; and (3) incomplete medical records. Clinical and follow-up data of patients who had undergone TPE for late complications of radiation-induced pelvic injury between March 2020 and September 2022 at the Sixth Affiliated Hospital of Sun Yat-sen University were analyzed. Perioperative recovery, postoperative complications, perioperative deaths, and quality of life 1 year postoperatively were recorded.Results:The study cohort comprised 14 women, nine of whom had recto-vagino-vesical fistulas, two vesicovaginal fistulas, one ileo-vesical fistula and rectal necrosis, one ileo-vesical and rectovaginal fistulas, and one rectal ulcer and bilateral ureteral stenosis. The mean duration of surgery was 592.1±167.6 minutes and the median blood loss 550 (100–6000) mL. Ten patients underwent intestinal reconstruction, and four the Hartmann procedure. Ten patients underwent urinary reconstruction using Bricker's procedure and 7 underwent pelvic floor reconstruction. The mean postoperative hospital stay was 23.6±14.9 days. Seven patients (7/14) had serious postoperative complications (Clavien-Dindo IIIa to IVb), including surgical site infections in eight, abdominopelvic abscesses in five, pulmonary infections in five, intestinal obstruction in four, and urinary leakage in two. Empty pelvis syndrome (EPS) was diagnosed in five patients, none of whom had undergone pelvic floor reconstruction. Five of the seven patients who had not undergone pelvic floor reconstruction developed EPS, compared with none of those who had undergone pelvic floor reconstruction. One patient with EPS underwent reoperation because of a pelvic abscess, pelvic hemorrhage, and intestinal obstruction. There were no perioperative deaths. During 18.9±10.1 months of follow-up, three patients died, two of renal failure, which was a preoperative comorbidity, and one of COVID-19. The remaining patients had gradual and significant relief of symptoms during follow-up. QLQ-C30 assessment of postoperative quality of life showed gradual improvement in all functional domains and general health at 1, 3, and 6 months postoperatively (all P<0.05). Conclusions:TPE is a feasible procedure for treating late complications of radiation-induced pelvic injury combined with complex pelvic fistulas. TPE is effective in alleviating symptoms and improving quality of life. However, the indications for this procedure should be strictly controlled and the surgery carried out only by experienced surgeons.