The Value of Intravoxel Incoherent Motion Diffusion-Weighted Magnetic Resonance Imaging Combined With Texture Analysis of Evaluating the Extramural Vascular Invasion in Rectal Adenocarcinoma

Predictive value of a nomogram based on DCE-MRI and DWI quantitative parameters and serum CEA level for risk of postoperative recurrence/metastasis of rectal cancer

BACKGROUND

The prognosis of rectal cancer is poor, and early prediction of recurrence and metastasis after radical surgery is of great significance for improving its prognosis. This study integrated multiple influencing factors such as multimodal magnetic resonance imaging (MRI) parameters, tumor markers, and clinicopathological features to develop a nomogram to provide a basis for the development of clinical intervention measures for this malignancy.

AIM

To develop a nomogram based on dynamic contrast enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) quantitative parameters and serum carcinoembryonic antigen (CEA) level, and to analyze the predictive value of this model for the risk of postoperative recurrence and metastasis of rectal cancer, so as to guide the development of clinical intervention measures for this malignancy.

METHODS

A total of 120 patients who underwent laparoscopic-assisted radical resection of rectal cancer at our hospital from March 1, 2019 to February 28, 2022 were selected as research subjects. According to the presence of recurrence/metastasis within 1 year after surgery, the patients were divided into a recurrence/metastasis group (n = 29) and a no recurrence/metastasis group (n = 91). The relevant parameters [apparent diffusion coefficient (ADC), transfer rate constant (Ktrans), blood return constant (Kep), and extravascular extracellular space volume fraction (Ve)] of multimodal MRI imaging techniques were compared between the two groups to analyze their predictive value for postoperative recurrence/metastasis. Univariate analysis with Lasso model screening for predictive factors related to postoperative recurrence/metastasis was performed, and logistic regression analysis was used to analyze the influencing factors of postoperative recurrence/metastasis. A nomogram was developed based on the influencing factors identified, and the predictive value of the model for postoperative recurrence/metastasis was assessed. Calibration curve and decision curve analysis (DCA) were used to verify the calibration degree and clinical effectiveness of the model, respectively.

RESULTS

ADC in the recurrence/metastasis group was lower than that in the no recurrence/metastasis group, while Ktrans and Kep were higher than those in the no recurrence/metastasis group (P < 0.05). Obstruction, degree of differentiation, clinical stage, lymph node metastasis, postoperative CEA, ADC, Ktrans, and Kep were identified to be independent influencing factors on postoperative recurrence/metastasis (P < 0.05). The area under the curve of the nomogram was higher than that of ADC, Ktrans, and Kep combined (P < 0.05), and the nomogram had good calibration and clinical efficacy.

CONCLUSION

The nomogram developed based on DCE-MRI and DWI quantitative parameters and serum CEA level has appreciated predictive value for postoperative recurrence/metastasis of rectal cancer, and clinical intervention measures can be formulated according to these high risk factors to reduce the risk of postoperative recurrence/metastasis.

Rectal MRI Interpretation After Neoadjuvant Therapy

In recent years, several key advances in the management of locally advanced rectal cancer have been made, including the implementation of total mesorectal excision as the standard surgical approach; use of neoadjuvant chemoradiotherapy in selected patients with a high risk of local recurrence, and finally, adoption of organ preservation strategies, through either local excision or nonoperative management in selected patients with clinical complete response following neoadjuvant chemoradiotherapy. This review aims to shed light on the role of rectal MRI in the assessment of treatment response after neoadjuvant therapy, which is especially important given the growing feasibility of nonoperative management. First, an overview of current neoadjuvant therapies and response assessment based on digital rectal examination, endoscopy, and MRI will be provided. Second, the use of a high-quality restaging rectal MRI protocol will be presented. Third, a step-by-step approach to assessing treatment response on restaging rectal MRI following neoadjuvant treatment will be outlined, acknowledging challenges faced by radiologists during MRI interpretation. Finally, research related to response assessment will be discussed. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 3.