Diagnosis of superficial endometriosis on transvaginal ultrasound by visualization of peritoneum of pouch of Douglas.

OBJECTIVE: Around 80% of women with endometriosis have superficial endometriosis (SE) rather than ovarian or deep endometriosis (DE). However, to date, advances in non-invasive, imaging-based diagnosis have been limited to DE or ovarian disease. The objective of this study was to determine whether we can detect SE on transvaginal ultrasound scan (TVS) by assessing the peritoneum of the pouch of Douglas (POD). METHODS: This was a retrospective diagnostic test study following a change in practice to include POD peritoneum assessment for SE during TVS at a tertiary London hospital. Eligible patients underwent TVS by a single clinician trained in endometriosis scanning and a subsequent surgical procedure (laparoscopy) between April 2018 and September 2021. Participants formed a consecutive series. The TVS findings were compared with those of laparoscopy as the gold standard. Comparison of TVS findings with intraoperative findings was performed by calculating the diagnostic test performance measures (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and positive and negative likelihood ratios). RESULTS: The study included a total of 100 patients. We found that 43/100 (43.0%) patients had no endometriosis, 33/100 (33.0%) had SE and 24/100 (24.0%) had DE on laparoscopy. SE was correctly detected on TVS in 17/33 patients, with a sensitivity of 51.5% (95% CI, 33.5-69.2%), specificity of 94.0% (95% CI, 85.4-98.4%), PPV of 81.0% (95% CI, 60.8-92.1%) and NPV of 79.7% (95% CI, 73.4-84.9%). DE was correctly diagnosed in 20/24 cases, including all ovarian cases, with a sensitivity of 83.3% (95% CI, 62.3-95.3%), specificity of 97.4% (95% CI, 90.8-99.7%), PPV of 90.9% (95% CI, 71.6-97.5%) and NPV of 94.9% (95% CI, 88.3-97.8%). The detection of SE on TVS was most accurate in the POD (sensitivity, 50.0%; specificity, 96.4%; PPV, 76.9%; NPV, 88.9%). CONCLUSIONS: This study shows that the detection of SE in the POD is possible using routine TVS. While negative TVS does not reliably confirm the absence of disease or replace diagnostic laparoscopy, positive TVS facilitates non-invasive diagnosis for a much larger group of women than was previously possible. This should help to reduce the time from the onset of symptoms to diagnosis and enable initiation of medical treatment without the risk, cost and delay associated with a surgical diagnosis. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Primary cystic echinococcosis of the peritoneum: a case report.

BACKGROUND: Peritoneal cystic echinococcosis happens usually after traumatic rupture or after surgical treatment. Primary peritoneal cystic echinococcosis is a very rare case that constitutes a diagnostic and therapeutic challenge. CASE REPORT: A 30-year-old Tunisian man was admitted for hypogastric pain since 4 months. He has a 10 cm hypogastric mass. Biological-tests were normal. A computed tomography Scan showed a cystic mass on the pelvis measuring 13 × 17 cm without echinococcosis cyst in the liver. The patient was operated and we found a cystic mass of 17 cm located on the Douglas cul-de-sac that suggest a pelvic hydatid cyst. We have performed an aspiration of the cyst confirms the diagnosis followed by injection of hypertonic solution, extarction of the germinal layer and a maximal reduction of the pericyst. The postoperative course was uneventful. CONCLUSION: Trough our case, we try to focus on the diagnosis and therapeutic options of this rare entity that we should think of in front of a patient with isolated peritoneal cyst especially in endemic country.

Bland-Altman agreement analysis between CT predicted and surgical peritoneal cancer index in pseudomyxoma peritonei of appendiceal origin.

Peritoneal cancer index (PCI) is the surgical variable most commonly used to quantify the extent of peritoneal metastases for pseudomyxoma peritonei (PMP) patients. The present study aimed to investigate the agreement between CT predicted and surgical PCI by the Bland-Altman method for PMP of appendiceal origin. A total of 167 PMP patients of appendiceal origin were included between 2016 and 2021. Bland-Altman analysis was performed for both total PCI and selected PCI (regions 2 + 9-12). After the Bland-Altman plot was drawn, the mean bias and its 95% limit of agreements (LoAs) was quantified. Besides, the correlation coefficients between CT-PCI and surgical PCI were also been calculated. The Bland-Altman plot showed the mean bias ± SD between total CT-PCI and surgical PCI as 0.431 ± 3.005, with the LoAs from - 5.459 to 6.321. There were nine points of difference in total PCI exceeded the 95% LoAs, with the rate of 5.39% (9/167). As for selected CT-PCI, Bland-Altman plot showed the mean bias ± SD between selected CT-PCI and surgical PCI as - 0.287 ± 1.955, with the LoAs from - 4.118 to 3.544. There were ten points of difference in selected PCI exceeded the 95% LoAs, with the rate of 5.99% (10/167). The Spearman's rank correlation coefficient between total CT-PCI and surgical PCI was 0.911, P < 0.001, as for selected CT-PCI and surgical PCI, the coefficient was 0.909, P < 0.001. Although there was a strong correlation for both total and selected CT-PCI with surgical PCI, however, the agreement is still not good in Bland-Altman analysis, which suggested that CT-PCI cannot predict surgical PCI accurately even in professional PMP treatment centers. In brief explanation, CT makes it difficult to distinguish the borderline between tumor tissue and mucus and to detect tumor lesions in the small intestine regions, which caused overestimation or underestimation by CT-PCI. In the future, a multiple linear regression model based on CT-PCI might accurately predict surgical PCI preoperatively.

CT-based deep learning model: a novel approach to the preoperative staging in patients with peritoneal metastasis.

Peritoneal metastasis (PM) is a frequent manifestation of advanced abdominal malignancies. Accurately assessing the extent of PM before surgery is essential for patients to receive optimal treatment. Therefore, we propose to construct a deep learning (DL) model based on enhanced computed tomography (CT) images to stage PM preoperatively in patients. All 168 patients with PM underwent contrast-enhanced abdominal CT before either open surgery or laparoscopic exploration, and peritoneal cancer index (PCI) was used to evaluate patients during the surgical procedure. DL features were extracted from portal venous-phase abdominal CT scans and subjected to feature selection using the Spearman correlation coefficient and LASSO. The performance of models for preoperative staging was assessed in the validation cohort and compared against models based on clinical and radiomics (Rad) signature. The DenseNet121-SVM model demonstrated strong patient discrimination in both the training and validation cohorts, achieving AUC was 0.996 in training and 0.951 validation cohort, which were both higher than those of the Clinic model and Rad model. Decision curve analysis (DCA) showed that patients could potentially benefit more from treatment using the DL-SVM model, and calibration curves demonstrated good agreement with actual outcomes. The DL model based on portal venous-phase abdominal CT accurately predicts the extent of PM in patients before surgery, which can help maximize the benefits of treatment and optimize the patient's treatment plan.

A Case of a Fixed Giant Peritoneal Loose Body outside the Peritoneum and near the Rectovesical Excavation.

A peritoneal loose body (PLB) is tissue completely separated from other intraperitoneal organs. It is rare and usually found incidentally during laparotomy, examination, or autopsy. PLBs are usually located free in the peritoneal cavity and not in the extraperitoneal space. They are thought to originate when epiploic appendices are released into the abdominal cavity after ischemic necrosis. We report a case of a giant PLB outside the peritoneal cavity, adjacent to the rectovesical excavation, that was identified preoperatively inan asymptomatic 83-year-old man undergoing evaluation for cholecystolithiasis. Computed tomography revealed a mass with well-defined margins in the rectovesical excavation. The mass (diameter, 60 mm) consisted of a calcified core and peripheral soft tissue and did not appear to invade adjacent organs. Although there were no symptoms or tumor growth over time, we scheduled a laparoscopic extraction for definitive diagnosis. On laparoscopic exploration, a white ovoid mass was found in the rectovesical excavation; there was no invasion of adjacent organs. We diagnosed a giant PLB. Postoperative recovery was uneventful. Most PLBs are asymptomatic and do not require surgery, except when symptoms are present, when the PLB is large, or when malignancy is suspected. PLB is rarely extraperitoneal and is usually freely mobile; however, in our patient, it was fixed and outside the abdominal cavity, near the rectovesical fossa. Although it could not be diagnosed preoperatively as being extraperitoneal, imaging findings were typical of PLB; thus, it was possible to remove the mass laparoscopically without bowel resection.

Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study.

INTRODUCTION: To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement. METHODS: Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy. RESULTS: Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR. CONCLUSIONS: Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface.

The added value of CEUS and ultrasound-guided biopsy in diagnosing an aggressive desmoplastic small round cell tumour of peritoneum in a young male. A case report.

Desmoplastic small round cell tumour (DSRCT) is a rare and highly aggressive mesenchymal neoplasm with poor prognosis that develops in male adolescents and young adults. We report the case of a 32-year-old male admitted with abdominal distension and ascites. An ultrasonography (US) scan showed multiple peritoneal masses with large ascites. The dominant mass had a hypervascular homogenous aspect at contrast-enhanced ultrasound with wash-out in the venous phase. Thoracoabdominal CT, performed for staging the disease, confirmed the US aspect. The US-guided percutaneous biopsy revealed DSRCT of the peritoneum. Chemotherapy was then started with minimal clinical improvement, increase in tumoral burden and death after three months. US and US-guided biopsy played an essential role in diagnosing this case. The aggressive course of the disease and seeding at paracentesis sites are the particularities of the presented case.

Primary peritoneal serous carcinoma: a primer for radiologists.

Primary peritoneal serous carcinoma (PPSC) is a rare primary peritoneal tumor characterized by a unique range of clinical features and imaging findings. Though it shares many clinical, histologic, and imaging features with serous ovarian carcinoma, it remains a distinct clinical entity. Although less common than its primary ovarian counterpart, PPSC is characterized by a prognosis that is often equally poor with presentations common in late stages of disease. Key imaging modalities used in the evaluation of PPSC include ultrasound, CT, MRI, and PET/CT. For radiologists, an understanding of the pertinent imaging findings, pathologic correlations, and clinical features of PPSC is essential for arriving at the correct diagnosis and guiding the subsequent appropriate management of this complex malignancy.

Quantitative Indocyanine Green Fluorescence Imaging Assessment for Nonmucinous Peritoneal Metastases: Preliminary Results of the ICCP Study.

BACKGROUND: In selected patients with peritoneal metastases of colorectal origin, complete cytoreduction has been the main single prognostic factor influencing long-term outcomes. In these patients, indocyanine green fluorescence imaging seems to be useful in detecting small subclinical peritoneal implants. However, quantitative fluorescence analysis has not yet been established as standard. OBJECTIVE: This study aimed to evaluate the sensitivity and specificity of quantitative indocyanine green fluorescence assessment in the detection of peritoneal metastases of nonmucinous colorectal origin. DESIGN: This is a single-center, single-arm, low-intervention prospective trial. SETTINGS: A fluorescence assessment device was used for intraoperative fluorescence quantitative assessment. PATIENTS: Consecutive patients diagnosed with peritoneal metastases of colorectal origin who met the inclusion criteria were selected for curative surgery. INTERVENTIONS: Intravenous indocyanine green was administered 12 hours before surgery. Cytoreduction was performed through nodule identification under white light and then under indocyanine green. Finally, ex vivo fluorescence was assessed. MAIN OUTCOME MEASURES: The primary outcomes measured were the sensitivity and specificity of quantitative fluorescence. RESULTS: The first 11 enrolled patients were included in this preliminary analysis. In total, 52 nodules were resected, with 37 (71.1%) being diagnosed as malignant in the histopathological analysis. Of those, 5 (13.5%) were undetectable under white light and were identified only with fluorescence. A total of 15 nonmalignant nodules were detected under white light, 8 (53.3%) of which were fluorescence negative. Fluorescence greater than 181 units might be the threshold of malignancy, with a sensitivity and specificity of 89.0% and 85.0%, whereas uptake less than 100 units appears to correlate with a benign pathology. LIMITATIONS: The limited sample size, the physiological uptake, and excretion of indocyanine green might interfere with the assessment of unnoticed implants in the bowel serosa and liver. CONCLUSIONS: Quantitative indocyanine green seems to be useful for the assessment of nonmucinous colorectal peritoneal metastases. Fluorescence uptake greater than 181 units appears to correlate with malignancy, whereas uptake less than 100 units appears to correlate with a benign pathology. See Video Abstract at http://links.lww.com/DCR/B743. EVALUACIN CUANTITATIVA DE IMGENES DE FLUORESCENCIA CON VERDE DE INDOCIANINA PARA METSTASIS PERITONEALES NO MUCINOSAS RESULTADOS PRELIMINARES DEL ESTUDIO ICCP: ANTECEDENTES:En pacientes seleccionados con metástasis peritoneales de origen colorrectal, la citorreducción com-pleta ha sido el único factor pronóstico principal que influye en el resultado a largo plazo. En estos pacientes, las imágenes de fluorescencia con verde de indocianina parecen ser útiles para detectar pequeños implantes peritoneales subclínicos. Sin embargo, el análisis cuantitativo de fluorescencia aún no se ha establecido como estándar.OBJETIVO:Evaluar la sensibilidad y especificidad de la evaluación cuantitativa de fluorescencia verde de indo-cianina, en la detección de metástasis peritoneales de origen colorrectal no mucinoso.DISEÑO:Ensayo prospectivo de intervención baja de un solo brazo y un solo centro.ENTORNO CLINICO:El dispositivo se utilizó para la evaluación cuantitativa de fluorescencia intraoperatoria.PACIENTES:Pacientes consecutivos diagnosticados con metástasis peritoneales de origen colorrectal, selecciona-dos para cirugía curativa y que cumplieron con los criterios de inclusión.INTERVENCIONES:Se administró verde de indocianina por vía intravenosa 12 h antes de la cirugía. La citorreducción se realizó mediante identificación de nódulos con luz blanca y luego con verde de indocianina. Final-mente, se evaluó la fluorescencia ex vivo.PRINCIPALES MEDIDAS DE VALORACION:Sensibilidad y especificidad cuantitativa de la fluorescencia.RESULTADOS:Los primeros 11 pacientes fueron incluidos en este análisis preliminar. En total se resecaron 52 nódu-los, siendo 37 (71,1%) diagnosticados como malignos en el análisis histopatológico. De ellos, 5 (13,5%) eran indetectables bajo luz blanca y solamente se identificaron con fluorescencia. Se detec-taron un total de 15 nódulos no malignos bajo luz blanca, de los cuales 8 (53,3%) fueron fluorescen-tes negativos. La fluorescencia superior a 181 unidades podría ser el umbral de malignidad, con una sensibilidad y especificidad del 89,0% y el 85,0% respectivamente; mientras que la captación por debajo de 100 unidades parece correlacionarse con una patología benigna.LIMITACIONES:El tamaño limitado de la muestra; la captación fisiológica y la excreción de verde de indocianina pueden interferir con la evaluación de implantes inadvertidos en la serosa intestinal y el hígado.CONCLUSIONES:La cuantificación del verde de indocianina, parece ser útil en la evaluación de metástasis peritonea-les colorrectales no mucinosas. La captación de fluorescencia por encima de 181 unidades parece correlacionarse con la malignidad, mientras que la captación por debajo de 100 unidades parece co-rrelacionarse con una patología benigna. Consulte Video Resumen en http://links.lww.com/DCR/B743. (Traducción - Dr. Fidel Ruiz Healy).

Tolerance of peritoneal and residual renal function to intraperitoneal gadolinium-based agents: An animal experimental study of magnetic resonance peritoneography.

BACKGROUND: MR (Magnetic resonance) peritoneography is sensible for continuous ambulatory peritoneal dialysis (CAPD)-related complications, which could offer excellent soft-tissue contrast and allows a multiplanar imaging evaluation of complications. However, there is no study about the optimal concentration of the gadolinium-based agents nor the side effects of gadolinium-based agents on peritoneum and residual renal function. METHOD: Five different groups of uremic rats and two groups of normal rats were injected with a 40-ml mixture of peritoneal dialysate and gadolinium-based agents at varying concentrations prior to MR peritoneography. Thereafter, MR image obtained was evaluated by two experienced radiologists blinded to the concentrations. Peritoneal morphology and thickness of the uremic rats were also assessed using hematoxylin and eosin and Masson staining. Residual renal function was evaluated using serum creatinine levels and hematoxylin and eosin (HE) staining of pathological kidney sections. RESULTS AND CONCLUSION: The gadolinium-based agents used in this experiment have no significant effect on residual renal function. There is no obvious difference in the image quality at the different gadolinium-based agents concentration. Due to the adverse effects of gadolinium-based agents in the previous studies, we suggest reducing the dose of gadolinium-based agents during MR peritoneography to the lowest limits.

Incisional hernia repair in rats: description of the sublay technique under videomagnification system

Purpose: To describe the technique of sublay correction of incisional hernia in Wistar rats under videomagnification system. Methods: Five male rats of the species Rattus norvegicus, of the Wistar lineage, with body weight between 250­350 g and 60 days old were used. Incisional hernia was inducted in all animals. After that, the incisional hernia was immediately corrected by the sublay method. Results: There were no cases of recurrence of the incisional hernia after placement of the polypropylene mesh using the sublay technique. No postoperative complications were observed. Conclusions: The technique is suitable for execution in Wistar rats.

Case Report: Disseminated Cysticercosis due to Intentional Ingestion of Parasitic Worm Eggs for Weight Loss.

A 20-year-old female resident of Beijing intended to consume the eggs of the parasitic worm, Taenia saginata, for weight loss; however, she apparently inadvertently ingested Taenia solium (pork tapeworm) eggs, which resulted in disseminated cysticercosis. Cysticerci developed in the brain, tongue, muscles, liver, peritoneum, and subcutaneous tissues. She was administered oral albendazole and praziquantel. After four 10-day courses of treatment, most of the cysts disappeared and she recovered. After 3 years, the patient remains in good health.

Pressurized hydrodissection for CT-guided percutaneous peritoneal navigation: The hydro jet technique.

The purpose of this paper is to evaluate the effectiveness of a new technique of hydrodissection for peritoneal structures displacement during preoperative localization markers placement. We retrospectively reviewed two cases of percutaneous fiducial marker placement prior rescue retroperitoneal lymphadenectomy. In both cases pressurized 5% dextrose in water (D5W) was used to hydrodissect the peritoneal space and securely reach the lymph nodes. Two patients were submitted to water jet technique for transperitoneal trespassing to reach the retroperitoneum. The volume of fluid used to navigate was 125-200 mL and the mean time to cross the peritoneum was 6 min 47 s (ranging from 3″26' to 10″24'). In conclusion, Bowel and small vessels displacement using pressurized D5W is a safe method to reach retroperitoneal space during percutaneous procedures.

Development of a rat capnoperitoneum phantom to study drug aerosol deposition in the context of anticancer research on peritoneal carcinomatosis.

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a promising approach with a high optimization potential for the treatment of peritoneal carcinomatosis. To study the efficacy of PIPAC and drugs, first rodent cancer models were developed. But inefficient drug aerosol supply and knowledge gaps concerning spatial drug distribution can limit the results based on such models. To study drug aerosol supply/deposition, computed tomography scans of a rat capnoperitoneum were used to deduce a virtual and a physical phantom of the rat capnoperitoneum (RCP). RCP qualification was performed for a specific PIPAC method, where the capnoperitoneum is continuously purged by the drug aerosol. In this context, also in-silico analyses by computational fluid dynamic modelling were conducted on the virtual RCP. The physical RCP was used for ex-vivo granulometric analyses concerning drug deposition. Results of RCP qualification show that aerosol deposition in a continuous purged rat capnoperitoneum depends strongly on the position of the inlet and outlet port. Moreover, it could be shown that the droplet size and charge condition of the drug aerosol define the deposition efficiency. In summary, the developed virtual and physical RCP enables detailed in-silico and ex-vivo analyses on drug supply/deposition in rodents.

Diagnostic accuracy of transvaginal sonography for detecting parametrial involvement in women with deep endometriosis: systematic review and meta-analysis.

OBJECTIVE: To evaluate the accuracy of transvaginal sonography (TVS) for detecting parametrial deep endometriosis, using laparoscopy as the reference standard. METHODS: A search was performed in PubMed/MEDLINE and Web of Science for studies evaluating TVS for detecting parametrial involvement in women with suspected deep endometriosis, as compared with laparoscopy, from January 2000 to December 2020. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was used to evaluate the quality of the studies. Pooled sensitivity, specificity and positive and negative likelihood ratios for TVS in the detection of parametrial deep endometriosis were calculated, and the post-test probability of parametrial deep endometriosis following a positive or negative test was determined. RESULTS: The search identified 134 citations. Four studies, comprising 560 patients, were included in the analysis. The mean prevalence of parametrial deep endometriosis at surgery was 18%. Overall, the pooled estimated sensitivity, specificity and positive and negative likelihood ratios of TVS in the detection of parametrial deep endometriosis were 31% (95% CI, 10-64%), 98% (95% CI, 95-99%), 18.5 (95% CI, 8.8-38.9) and 0.70 (95% CI, 0.46-1.06), respectively. The diagnostic odds ratio was 26 (95% CI, 10-68). Heterogeneity was high. Visualization of a lesion suspected to be parametrial deep endometriosis on TVS increased significantly the post-test probability of parametrial deep endometriosis. CONCLUSION: TVS has high specificity but low sensitivity for the detection of parametrial deep endometriosis. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Assessment of peritoneal thickness using CT in relation to dialysis adequacy in peritoneal dialysis patients.

Studies assessing peritoneal thickness by CT in peritoneal dialysis (PD) patients are lacking. In this study, we aimed to investigate the association between peritoneal thickness as measured by CT and dialysis adequacy with peritoneal membrane characteristics in PD patients. Ninety-four PD patients were enrolled. Peritoneal thickness was measured by CT. Patients with and without a decrease in Kt/V of at least 0.3 over time were classified as Group 1 and Group 2, respectively. An increase of 0.1 unit of dialysate/plasma (D/P) creatinine over time were considered significant. The relationship between peritoneal membrane thickness, change in Kt/V, and peritoneal membrane characteristics were investigated. There were 31 (33.0%) patients in Group 1. The duration of PD (86.0 ± 64.1 vs. 59.6 ± 45.2 months, p: 0.023), peritoneal thickness (1.02 ± 0.37 vs. 0.87 ± 0.21 mm, p: 0.015), peritoneal calcification (7 [22.6%] vs. 3 [4.8%] patients, p: 0.013], increased D/P creatinine ratio (14 [45.2%] vs. 14 [22.2%] patients, p: 0.031) and CRP (13.9 ± 11.2 vs. 7.1 ± 4.8 mg/L, p: 0.045) were significantly higher in Group 1, whereas albumin (3.6 ± 0.5 vs. 3.8 ± 0.6 g/dL, p: 0.047) and parathyroid hormone (355.2 ± 260.2 vs. 532.1 ± 332.9 ng/L, p: 0.015) levels were significantly lower. Peritoneal thickness was significantly correlated with duration of PD (r: 0.775, p < 0.001) and CRP (r: 0.282, p: 0.006). Regression analysis showed that peritoneal thickness (Exp (B) [95% CI]: 0.029 [0.003-0.253], p: 0.001) was independent predictor of decreased Kt/V in PD patients. In conclusion, prolonged PD duration and increased peritoneal thickness are associated with a decrease in Kt/V over time. CT may be an alternative and noninvasive method instead of peritoneal biopsy for determining the structural changes of the peritoneal membrane .