Three-dimension amide proton transfer MRI of rectal adenocarcinoma: correlation with pathologic prognostic factors and comparison with diffusion kurtosis imaging.

OBJECTIVES: To investigate the utility of 3D amide proton transfer (APT) MRI in predicting pathologic factors for rectal adenocarcinoma, in comparison with diffusion kurtosis imaging. METHODS: Sixty-one patients with rectal adenocarcinoma were enrolled in this prospective study. 3D APT and diffusion kurtosis imaging (DKI) were performed. Mean APT-weighted signal intensity (APTw SI), mean kurtosis (MK), mean diffusivity (MD), and ADC values of tumors were calculated on these maps. Pathological analysis included WHO grades, pT stages, pN stages, and extramural venous invasion (EMVI) status. Student's t test, Spearman correlation, and receiver operating characteristics (ROC) analysis were used for statistical analysis. RESULTS: High-grade rectal adenocarcinoma showed significantly higher mean APTw SI and MK values (2.771 ± 0.384 vs 2.108 ± 0.409, 1.167 ± 0.216 vs 1.045 ± 0.175, respectively; p < 0.05). T3 rectal adenocarcinoma demonstrated higher mean APTw SI and MK than T2 tumors (2.433 ± 0.467 vs 1.900 ± 0.302, p < 0.05). No kurtosis, diffusivity, and ADC differences were found between T2 and T3 tumors. Tumors with lymph node metastasis and EMVI involvement showed significantly higher mean APTw SI, MK. No difference was found in diffusivity and ADC between pN0 and pN1-2 groups, and EMVI-negative and EMVI-positive statuses. Mean APTw SI exhibited a significantly high positive correlation with WHO grades, demonstrating 92.31% sensitivity and 79.17% specificity for distinguishing low- from high-grade rectal adenocarcinoma, providing a better diagnostic capacity than MK, MD, and mean ADC values. CONCLUSION: 3D-APT could serve as a non-invasive biomarker for evaluating prognostic factors of rectal adenocarcinoma. KEY POINTS: • Mean APTw SI was significantly higher in high-grade compared to low-grade rectal adenocarcinoma. • Mean APTw SI was significantly higher in T3 stage rectal adenocarcinoma, with lymph node metastasis, or in EMVI-positive status. • APTw SI exhibited greater diagnostic capability in discriminating low-grade from high-grade rectal adenocarcinoma, compared with kurtosis, diffusivity, and ADC.

Comparative Analysis of Amide Proton Transfer MRI and Diffusion-Weighted Imaging in Assessing p53 and Ki-67 Expression of Rectal Adenocarcinoma.

BACKGROUND: The evaluation of prognostic factors in rectal carcinoma patients has important clinical significance. P53 status and the Ki-67 index have served as prognostic factors in rectal carcinoma. Amide proton transfer (APT) imaging has shown great potential in tumor diagnosis. However, few studies reported the value of APT imaging in evaluating p53 and Ki-67 status of rectal carcinoma. PURPOSE: To investigate the feasibility of amide proton transfer MRI in assessing p53 and Ki-67 expression of rectal adenocarcinoma, and compare it with conventional diffusion-weighted imaging (DWI). STUDY TYPE: Retrospective. POPULATION: Forty-three patients with rectal adenocarcinoma (age: 34-85 years). FIELD STRENGTH/SEQUENCE: 3T/APT imaging using a 3D turbo spin echo (TSE)-Dixon pulse sequence with chemical shift-selective fat suppression, 2D DWI, and 2D T2 -weighted TSE. ASSESSMENT: Mean tumor APT signal intensity (SImean ) and apparent diffusion coefficient (ADCmean ) were measured. Traditional tumor pathological analysis included WHO grades, pT (pathologic tumor) stages, and pN (pathologic node) stages. Expression levels of p53 and Ki-67 were determined by immunohistochemical assay. STATISTICAL TESTS: One-way analysis of variance (ANOVA); Student's t-test; Spearman's correlation coefficient; receiver operating characteristic (ROC) curve analysis. RESULTS: High-grade tumors, more advanced stage tumors, and tumors with lymph node involvement had higher APT SImean values: high grade (n = 15) vs. low-grade (n = 28), P < 0.001; pT2 (n = 10) vs. pT3 (n = 20) vs. pT4 (N = 13), P = 0.021; pN0 (n = 24) vs. pN1-2 (n = 19), P = 0.019. ADCmean differences were found in tumors with different pT stage: pT2 (n = 10) vs. pT3 (n = 20) vs. pT4 (N = 13), P = 0.013, but not in tumors with different histologic grade: high grade (n = 15) vs. low-grade (n = 28), P = 0.3536; or pN stage: pN0 (n = 24) vs. pN1-2 (n = 19), P = 0.624. Tumor with p53 positive status had higher APT SImean than tumor with negative p53 status (2.363 ± 0.457 vs. 2.0150 ± 0.3552, P = 0.014). There was no difference in ADCmean with p53 status (1.058 ± 0.1163 10-3 mm2 /s vs. 1.055 ± 0.128 10-3 mm2 /s, P = 0.935). APT SImean and ADCmean were significantly different in tumors with low and high Ki-67 status (1.7882 ± 0.11386 vs. 2.3975 ± 0.41586, P < 0.001; 1.1741 ± 0.093 10-3 mm2 /s vs. 1.0157 ± 0.10459 10-3 mm2 /s, P < 0.001, respectively). APT SImean exhibited a positive correlation with p53 labeling index and Ki-67 labeling index (r = 0.3741, P = 0.0135; r = 0.7048; P < 0.001, respectively). ADCmean showed no correlation with p53 labeling index, but a negative correlation with Ki-67 labeling index (r = -0.5543, P < 0.0001). ROC curves demonstrated that APT SImean had significantly higher diagnostic ability for differentiation of high Ki-67 expression of rectal adenocarcinoma than ADCmean (81.2% vs. 78.12%, 90.91% vs. 63.64; P < 0.001 vs. P = 0.017), while no difference was found in predicting p53 status (92.86% vs. 71.4%, 53.33% vs. 66.7%; P < 0.001 vs. P = 0.0471). DATA CONCLUSION: APT SImean was related to p53 and Ki-67 expression levels in rectal adenocarcinoma. APT imaging may serve as a noninvasive biomarker for assessing genetic prognostic factors of rectal adenocarcinoma. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

Predicting Treatment Response of Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer Using Amide Proton Transfer MRI Combined With Diffusion-Weighted Imaging.

OBJECTIVE: To evaluate amide proton weighted (APTw) MRI combined with diffusion-weighted imaging (DWI) in predicting neoadjuvant chemoradiotherapy (NCRT) response in patients with locally advanced rectal cancer (LARC). METHODS: 53 patients with LARC were enrolled in this retrospective study. MR examination including APTw MRI and DWI was performed before and after NCRT. APTw SI, ADC value, tumor size, CEA level before and after NCRT were assessed. The difference of the above parameters between before and after NCRT was calculated. The tumor regression grading (TRG) was assessed by American Joint Committee on Cancer's Cancer Staging Manual AJCC 8th score. The Shapiro-Wilk test, paired t-test and Wilcoxon Signed Ranks test, two-sample t-test, Mann-Whitney U test and multivariate analysis were used for statistical analysis. RESULTS: Of the 53 patients, 19 had good responses (TRG 0-1), 34 had poor responses (TRG 2-3). After NCRT, all the rectal tumors demonstrated decreased APT values, increased ADC values, reduced tumor volumes and CEA levels (all p < 0.001). Good responders demonstrated higher pre-APT values, higher Δ APT values, lower pre- ADC values and higher Δ tumor volumes than poor responders. Pre-APT combined with pre-ADC achieved the best diagnostic performance, with AUC of 0.895 (sensitivity of 85.29%, specificity of 89.47%, p < 0.001) in predicting good response to NCRT. CONCLUSION: The combination of APTw and DWI may serve as a noninvasive biomarker for evaluating and identifying response to NCRT in LARC patients.

Prevalence of Spirometra mansoni in dogs, cats, and frogs and its medical relevance in Guangzhou, China.

BACKGROUND: Sparganosis is an important parasitic disease in Guangzhou and is mainly acquired through the consumption of frog meat or contact with fresh frogs infected by larval stages (spargana) of the tapeworm species Spirometra mansoni. METHODS: In this study, the prevalence of intestinal S. mansoni infections (with adult parasites) in dogs and cats and of extraintestinal S. mansoni infections (with spargana) in frogs was assessed. In addition, a questionnaire survey was carried out among residents in Guangzhou City in order to evaluate their awareness about the medical and epidemiological relevance of Spirometra and sparganosis. RESULTS: In total, the feces of 229 dogs and 116 cats were examined for eggs, and 1949 frogs were examined for spargana. Sixty-three dogs (27.5%) and 47 cats (40.5%) had eggs in their feces. Two hundred and sixteen out of 416 wild Rana tigrina rugulosa Wiegmann frogs examined were sparganum-positive, with an infection rate of 51.9%, while the infection rate in Rana limnocharis Boie was 35.1% (13/37). None of the tested farmed frogs (including R. tigrina rugulosa and Rana catesbeiana) was positive (0/1382). Analysis of the questionnaire revealed the following results: (1) about 41.0% of residents in Guangzhou had some knowledge of sparganosis or sparganum infection, and information in TV programs was the most important way that residents learned about sparganosis. (2) About 59.9% of the residents ate frog meat. Eating the meat, viscera, or blood of animals, e.g., frogs, snakes, pigs, chicken, mice, and birds, in an improper way might be the main means by which residents acquire the infection. (3) The risk of sparganum infection was higher in males than in females. CONCLUSIONS: A high sparganum infection rate was observed in the wild frogs sold in agricultural product markets in Guangzhou. The infection was also serious in cats and dogs in Guangdong Province. With lifestyles and eating habits resulting in sparganum infection, it is necessary to focus on market management and community education in order to prevent the transmission of this disease in Guangzhou.

[Environmental quality of Guangzhou sea area].

Based on the water quality investigation data from August 2003 to August 2004, and by using single water quality parameter model, integrated water quality index model and eutrophication assessment model, this paper assessed the environmental quality of Guangzhou sea area. The results showed that the key pollutants were dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus, oil, Cu and Pb, with their annual average concentrations of 1.87 mg x L(-1), 0.049 mg x L(-1), 0.107 mg x L(-1), 6.07 microg x L(-1) and 1.43 microg x L(-1), respectively. Among the pollutants, DIN was the most important one. Its concentration exceeded the fourth standard of sea water quality, and decreased gradually from inner bay to outer bay. Under the effects of Pearl River water flow and land-based pollutants, most part of Guangzhou sea area was seriously polluted, and the annual averages of single parameter pollution index, integrated water quality index, and eutrophication index were 2.22, 6.80 and 48.44, respectively, which also decreased gradually from inner bay to outer bay, and from nearshore to offshore.