Role of dynamic contrast-enhanced MRI in predicting severe acute radiation-induced rectal injury in patients with rectal cancer

OBJECTIVES

To explore the potential of dynamic contrast-enhanced MRI (DCE-MRI) quantitative parameters in predicting severe acute radiation-induced rectal injury (RRI) in rectal cancer.

METHODS

This retrospective study enrolled 49 patients with rectal cancer who underwent neoadjuvant chemoradiotherapy and rectal MRI including a DCE-MRI sequence from November 2014 to March 2021. Two radiologists independently measured DCE-MRI quantitative parameters, including the forward volume transfer constant (Ktrans), rate constant (kep), fractional extravascular extracellular space volume (ve), and the thickness of the rectal wall farthest away from the tumor. These parameters were compared between mild and severe acute RRI groups based on histopathological assessment. Receiver operating characteristic curve analysis was performed to analyze statistically significant parameters.

RESULTS

Forty-nine patients (mean age, 54 years ± 12 [standard deviation]; 37 men) were enrolled, including 25 patients with severe acute RRI. Ktrans was lower in severe acute RRI group than mild acute RRI group (0.032 min-1 vs 0.054 min-1; p = 0.008), but difference of other parameters (kep, ve and rectal wall thickness) was not significant between these two groups (all p > 0.05). The area under the receiver operating characteristic curve of Ktrans was 0.72 (95% confidence interval: 0.57, 0.84). With a Ktrans cutoff value of 0.047 min-1, the sensitivity and specificity for severe acute RRI prediction were 80% and 54%, respectively.

CONCLUSION

Ktrans demonstrated moderate diagnostic performance in predicting severe acute RRI.

CLINICAL RELEVANCE STATEMENT

Dynamic contrast-enhanced MRI can provide non-invasive and objective evidence for perioperative management and treatment strategies in rectal cancer patients with acute radiation-induced rectal injury.

KEY POINTS

• To our knowledge, this study is the first to evaluate the predictive value of contrast-enhanced MRI (DCE-MRI) quantitative parameters for severe acute radiation-induced rectal injury (RRI) in patients with rectal cancer. • Forward volume transfer constant (Ktrans), derived from DCE-MRI, exhibited moderate diagnostic performance (AUC = 0.72) in predicting severe acute RRI of rectal cancer, with a sensitivity of 80% and specificity of 54%. • DCE-MRI is a promising imaging marker for distinguishing the severity of acute RRI in patients with rectal cancer.

MRI-detected tumor deposits in cT3 and cT4 rectal cancer following neoadjuvant chemoradiotherapy

OBJECTIVES

To evaluate the identification of tumor deposits (TDs) and the prognostic significance of an MRI tumor regression grade for TDs in patients with rectal cancer treated with neoadjuvant chemoradiotherapy (nCRT).

METHODS

Ninety-one patients with cT3 or cT4 rectal cancer who underwent surgery following nCRT between August 2014 and June 2020 were retrospectively analyzed. Changes in pre-nCRT MRI-detected TDs (mrTDs) were described as mrTD regression grade. The diagnostic performance of post-nCRT MRI-detected TDs (ymrTDs) was compared with histopathological reference standard. The correlation between ymrTDs, mrTD regression grade, and disease-free survival (DFS) was assessed.

RESULTS

The sensitivity and specificity of ymrTDs were 88.00% and 89.39%, respectively. The area under the receiver operating characteristic curve was 0.887 (95% confidence interval [CI]: 0.803-0.944). The 3-year DFS of patients with positive ymrTDs was significantly lower than of the negative group (44.83% vs 82.73%, p < 0.001). The 3-year DFS was 33.33% for patients with poor regression of mrTDs following nCRT and 55.56% for those with moderate regression, compared to 69.23% in good responders and 83.97% in patients without mrTDs (p < 0.001). On multivariable Cox regression, mrTD regression grade was the only independent MRI factor associated with DFS (p = 0.042).

CONCLUSIONS

Diagnostic performance of ymrTDs was moderate. The mrTD regression grade was independently correlated with DFS, which may have a prognostic implication for treatment and follow-up.

CLINICAL RELEVANCE STATEMENT

Patients with poor regression of MRI-detected tumor deposits may benefit from more aggressive treatments, such as chemoradiation therapy plus induction or consolidation chemotherapy.

KEY POINTS

• MRI provides a preoperative and noninvasive way to visualize tumor deposits (TDs) after neoadjuvant chemoradiotherapy (nCRT). • Post-nCRT MRI-detected TDs are a poor prognostic marker in cT3 and cT4 rectal cancer patients. • The regression of MRI-detected TDs after nCRT is associated with an improved disease-free survival.

Quantitative assessment of the microstructure of the mesorectum with different prognostic statuses by intravoxel incoherent motion diffusion-weighed magnetic resonance imaging

BACKGROUND

The mesorectum surrounding the rectum provides an ideal substrate for tumour spread. However, preoperative risk assessment is still an issue. This study aimed to investigate the microstructural features of mesorectum with different prognostic statuses by intravoxel incoherent motion diffusion-weighted imaging (IVIM DWI).

METHODS

Patients with pathologically proven rectal adenocarcinoma underwent routine high-resolution rectal magnetic resonance imaging (MRI) and IVIM DWI sequences were acquired. The MRI-detected circumferential resection margin (mrCRM) and extramural vascular invasion (mrEMVI) were evaluated. IVIM parameters of the mesorectum adjacent to (MAT) and distant from (MDT) the tumour were measured and compared between and within the prognostic factor groups.

RESULTS

The positive mrCRM (p_MAT < 0.001; p_MDT = 0.013) and mrEMVI (p_MAT = 0.001; p_MDT < 0.001) groups demonstrated higher D values in the MAT and MDT than the corresponding negative groups. Conversely, the positive mrCRM (p = 0.001) and mrEMVI (p < 0.001) groups both demonstrated lower f values in the MAT. Similarly, in the self-comparison between the MAT and MDT in the above subgroups, D showed a significant difference in all subgroups (p < 0.001 for all), and f showed a significant difference in the positive mrCRM (p = 0.001) and mrEMVI (p = 0.002) groups. Moreover, the MAT displayed a higher D* in the positive mrCRM (p = 0.014), negative mrCRM (p = 0.009) and negative mrEMVI groups (p < 0.001).

CONCLUSION

The microstructure of the mesorectum in patients with rectal cancer with poor prognostic status shows changes based on IVIM parameters. IVIM parameters might be promising imaging biomarkers for risk assessment of tumour spread in mesorectum preoperatively.

Hepatic mosaic enhancement pattern correlates with increased inflammatory activity and adverse therapeutic outcomes in patients with Crohn's disease

PURPOSE

This study aimed to evaluate the role of hepatic mosaic enhancement pattern (HMEP) on computed tomography images in the disease activity and therapeutic outcome of Crohn's Disease (CD).

METHODS

Twenty-five CD patients with HMEP comprised the HMEP group, and 25 CD patients without HMEP, who had a similar onset age, sex, and disease course with those in the HMEP group, comprised the non-HMEP group. No underlying liver/biliary disease was observed in any of the patients. Clinical characteristics, laboratory test results, Lémann index, and CD endoscopic index of severity (CDEIS) were compared between the groups using the Student t-, Mann-Whitney U, Chi square, or Fisher's exact tests. Patients received top-down, step-up, or traditional treatment during the follow-up period. After the 1-year follow-up, therapeutic outcomes (active inflammation [CDEIS > 3.5 if the endoscopic data were available, or C-reactive protein level > 5 mg/L if the endoscopic data were unavailable] or remission) were evaluated.

RESULTS

The occurrence rate of fistulas/abscesses was higher in the HMEP group (84%, 21/25) than in the non-HMEP group (48%, 12/25) with no statistical significance (P = 0.056). The HMEP group showed a higher C-reactive protein level (P = 0.001), erythrocyte sedimentation rate (P = 0.013), and blood platelet count (P = 0.005). There was no significant difference in therapeutic strategies between the groups (P = 0.509). The HMEP group showed a significantly lower remission ratio after anti-inflammatory treatment than the non-HMEP group (P = 0.045).

CONCLUSIONS

HMEP was correlated with increased inflammatory activity and adverse therapeutic outcomes in CD. This finding provided insights regarding novel markers of CD diagnosis and treatment.

Degree of Creeping Fat Assessed by Computed Tomography Enterography is Associated with Intestinal Fibrotic Stricture in Patients with Crohn's Disease: A Potentially Novel Mesenteric Creeping Fat Index

BACKGROUND AND AIMS

Emerging evidence points to a link between creeping fat and the pathogenesis of Crohn's disease [CD]. Non-invasive assessment of the severity of creeping fat on cross-sectional imaging modality has seldom been investigated. This study aimed to develop and characterize a novel mesenteric creeping fat index [MCFI] based on computed tomography [CT] in CD patients.

METHODS

MCFI was developed based on vascular findings on CT in a retrospective cohort [n = 91] and validated in a prospective cohort [n = 30]. The severity of creeping fat was graded based on the extent to which mesenteric fat extended around the intestinal circumference using the vessels in the fat as a marker. The accuracy of MCFI was assessed by comparing it with the degree of creeping fat observed in surgical specimens. The relationship between MCFI and fibrostenosis was characterized by determining if these correlated. The accuracy of MCFI was compared with other radiographic indices [i.e. visceral to subcutaneous fat area ratio and fibrofatty proliferation score].

RESULTS

In the retrospective cohort, MCFI had moderate accuracy in differentiating moderate-severe from mild fibrostenosis (area under the receiver operating characteristic [ROC] curve [AUC] = 0.799; p = 0.000). ROC analysis in the retrospective cohort identified a threshold MCFI of > 3 which accurately differentiated fibrostenosis severity in the prospective cohort [AUC = 0.756; p = 0.018]. An excellent correlation was shown between MCFI and the extent of fat wrapping in specimens in the prospective cohort [r = 0.840, p = 0.000]. Neither visceral to subcutaneous fat area ratio nor fibrofatty proliferation score correlated well with the degree of intestinal fibrosis.

CONCLUSIONS

MCFI can accurately characterize the extent of mesenteric fat wrapping in surgical specimens. It may become another non-invasive measure of CD fibrostenosis.

Apoptosis of hepatocarcinoma cells Hepg2 induced by Huaier extract through regulation of HBx and CEACAM1 gene expression

Huaier can effectively inhibit the growth of tumor cells by enhancing the immune system. However, the mechanism of its function is still not clear. The current study aimed to explore the possible mechanism of Huaier in inhibiting human hepatocarcinoma cells by observing its effect on proliferation and invasion in hepatocarcinoma cells, HepG2 and HepG2-X, which stably express the HBx gene, and by comparing the levels of mRNA transcription and protein expression of HBx and CEACAM1 in HepG2 cells and HepG2-X cells when treated with different concentrations of Huaier. HepG2 cells and HepG2-X cells were treated with 0, 1.5, 3.0, and 6.0 g/L-1 Huaier extract in vitro. MTT assay was used to measure the inhibition of cell proliferation. The transwell cell model coated with Matrigel glue was used to detect the invasion of HepG2 and HepG2-X cells in vitro. Flowcytometry was used to observe changes in cell cycle. Real-time PCR and Western blot were used to detect HBx and CEREAM1 mRNA transcription and protein expression separately. Huaier extract can inhibit HepG2 and HepG2-X cell proliferation in a time- and dose-dependent manner. The A value of HepG2-X cells in each group was higher than that of HepG2 cells. Compared with the control group, the invasion ability of HepG2 and HepG2-X cells decreased significantly after treatment with Huaier extract, in a dose-dependent manner. The cell cycle of HepG2 and HepG2-X was arrested at S phase. The distribution of G0/G1 phase decreased gradually with the increase of the concentration of Huaier extract, and the proportion of G0/G1 phase distribution declined. After treating with Huaier extract, mRNA transcription and protein expression of HBx in HepG2 and HepG2-X declined, while those of CEACAM1 increased, reflecting a dose-dependent manner (P less than 0.05). Therefore, we concluded that the inhibitory effect of Huaier extract on hepatocarcinoma cell proliferation might function through down regulation of HBx gene expression and upregulation of CEACAM1 gene expression.

Observation of cavity quantum-electrodynamic effects in a Nd:glass microsphere

In a Nd:glass microspherical cavity the enhancement and inhibition of spontaneous-emission processes that are due to cavity QED effects have been observed. The rates of the enhanced spontaneous emission are location dependent and reach a maximum value of more than 10(3) times the free-space value. The large enhancement strongly modifies the decay processes of Nd ions in glass, and the radiative properties of Nd:glass have been changed. As a result a new spectrum including new lasing wavelengths in the Nd:glass sphere has been observed.

Failure to detect hemagglutination-inhibiting antibodies with intact avian influenza virions

Avian influenza viruses replicate in a variety of mammals and birds, yet hemagglutination inhibition tests show that postinfection sera from these animals (e.g., ferrets and ducks) have insignificant levels of antibodies (Hinshaw et al., Infect. Immun. 34:354-361, 1981). This suggested that avian influenza viruses, in contrast to mammalian viruses, may not induce a significant humoral response. Studies reported here indicate that avian influenza viruses do induce high levels of antibodies in ferrets, ducks, and mice and produce long-lived memory for cytotoxic T-cells in mice. The failure to detect hemagglutination-inhibiting antibodies to avian viruses was explained by the finding that antibodies to avian influenza viruses were not detectable in hemagglutination inhibition tests with intact virus yet were readily demonstrable when hemagglutinin subunits were used. In addition, these sera contained high levels of neutralizing antibodies to the avian virus. These findings suggest that the hemagglutinins of avian and mammalian influenza viruses may differ in their accessibility to antibodies or the biological consequence of antibody attachment or both. The practical consequence of these studies is that hemagglutination inhibition tests with intact avian viruses fail to detect antibody and do not correlate with virus neutralization. The avian virus used in these studies, A/Mallard/NY/6870/78 (H2N2), replicated and caused mortality in BALB/c mice, emphasizing that the host range and virulence of avian viruses extends to mammals. The above findings suggest that avian viruses could infect mammals in nature, yet seroepidemiological studies with conventional hemagglutination inhibition tests could give misleading results.