Direct Comparison of the Thickness of the Parietal Peritoneum Using Peritoneal Biopsy and Ultrasonography of the Abdominal Wall in Patients Treated with Peritoneal Dialysis

Abstract

Background Long-term treatment with peritoneal dialysis (PD) results in peritoneal fibrosis. Peritoneal biopsies have been used to determine the severity of fibrosis. Ultrasonography (US) of the abdominal wall has been used to measure peritoneal thickness non-invasively. However, direct comparison of both methods in the same patient has never been done. Furthermore, the validity of US to measure peritoneal thickness has not been investigated. Methods We performed 3 studies: 1) a human biopsy study to compare US measurement of peritoneal thickness with histological examination; 2) a human cadaver study to investigate the effect of removing the peritoneum on US results; and 3) a phantom study in which we used US to measure the thickness of membrane-like structures with a known thickness to investigate the influence of different US settings. Results The median thickness in biopsies of the peritoneum was 113 μm (interquartile range [IQR] 72 –129 μm), while this was 370 μm (IQR 324 – 458 μm) when measured by US ( p < 0.0001). The mean difference between the 2 measures was -257 μm (limits of agreement -4.6 and -511 μm). In the cadaver study, removal of the peritoneum did not have an effect on the presence or thickness of the hyperechoic line reported to represent the peritoneum. In the phantom study, results were highly dependent on frequency of the transducer, scan depth, and gain settings. Conclusions Ultrasonography results differ markedly from histological measurement using peritoneal biopsies. However, the hyperechoic line generated by US represents the interface between 2 neighboring tissues and not a separate morphological structure. Moreover, its thickness is greatly influenced by user-defined US settings.

Hyperspectral evaluation of peritoneal fibrosis in mouse models

“…Another problem of the translation is light penetration depth. Human peritoneum is thicker compared to mouse peritoneum (≈ 100 µm [28] vs few µm in mice as seen from histology in our study), therefore in humans light is reflected mostly from the peritoneum while in mice it penetrates to the underlying tissues. A useful consequence is, that although only changes close to the surface would be detected in humans, they have a greater effect on the recorded spectra due to the higher probability of tissue-light interactions along this longer path.…”

“…Currently, biopsy is a golden standard to evaluate peritoneal changes in humans, which can be limited by size and sampling positions of the evaluated regions [26,27]. Although it was recently demonstrated that an ultrasound based examination of peritoneal membrane thickness is possible [28], it is inaccurate and requires experienced personnel. Therefore, alternative techniques are still needed.…”

An anatomical comparison of the fasciae of the thigh: A macroscopic, microscopic and ultrasound imaging study

“…Acoustic impedance, which refers to the physical property of a tissue, depends on the density and the propagation speed of US waves in the tissue. The intensity of the reflected echo and the thickness of the hyper‐echogenic lines generated are proportional to the difference in the acoustic impedance between the different tissue interfaces (Abrahams et al, 2019). Müller et al (2020) demonstrated that in subcutaneous tissue, changing the speed of sound did not impact the technical accuracy; rather biological features (such as furrowed borders and visco‐elastic deformations of adipose tissue) seemed to affect its reliability.…”

Development of Rotational Intraperitoneal Pressurized Aerosol Chemotherapy to Enhance Drug Delivery into the Peritoneum

“…The results showed no differences in creatinine, bilirubin, ALP, AST, ALT, GGT, or CRP before RIPAC, immediately after RIPAC, or on days 1, 2, 3, or 4. 50 (38,64,3) 83 (31,98) 95 (36,122) 69 (20,154) 86 (21, 97.1) 83 (38, 92.8) 0.978 ALT (IU/l) 37 (24,55) 37 (23,54) 38 (24,38) 45 (22,50) 51 (21,55) 50 (21,68) 63 (20,64) 0.982 GGT (IU/l) 59 (21,76) 49 (22,63) 53 (26,56) 48 (27,59) 54 (25,56) 51 (24,64) 55 ( All values were shown as median with range Discussion PIPAC has been suggested to be useful as palliative therapy for PM of recurrent or refractory solid tumors, which may lead to histologic regression, and thereby improve the quality of life [22][23][24][25]. Even if chemotherapeutic agents shown to be resistant in intravenous chemotherapy are used again in PIPAC, the agents may be absorbed into the peritoneal tumors by passive diffusion, which can be effective for treating PM by maintaining higher concentrations within tumor tissues while minimizing systemic absorption [26,27].…”

“…Although the relevant evidence is not de nitive, we hypothesized that differences in the histologic structures between the visceral and parietal peritoneum rather than the position of the nozzle could lead to the concentration distributions. When we consider that the penetration depth of RIPAC may range within 500 µm, we can expect that doxorubicin can penetrate soft extraperitoneal fat tissues beyond the parietal peritoneum [36], whereas penetration into the dense muscularis layer beyond the visceral peritoneum seems di cult [37,38]. Our ndings that the tissue concentrations of doxorubicin were lower in the visceral peritoneum than in the parietal peritoneum support this hypothesis, and lower tissue concentrations in the visceral peritoneum seemed to be related to the systemic absorption of doxorubicin in the mucosal layer instead of the direct penetration of doxorubicin into the peritoneum.…”