Diagnostic Value of 3.0 T Magnetic Resonance Imaging in Active Crohn's Disease.

BACKGROUND: Magnetic resonance enteroclysis (MRE) has been widely applied to diagnose Crohn's disease (CD). Magnetic resonance (MR) at 3.0 T improves signal-to-noise ratio (SNR), shortens image acquisition time, and shows more advantages. OBJECTIVE: This study aimed to retrospectively analyze the diagnostic value of 3.0 T MR imaging for active CD. METHODS: 48 CD patients hospitalized in our hospital from January 2021 to December 2022 were selected as the study subjects. These 48 CD patients underwent both double-balloon enteroscopy and 3.0 T MRE. All patients' arterial phase signal, venous phase signal, bowel wall, and bowel lumen of MRE were observed to identify whether they suffered from active CD. Based on the results of enteroscopy, the number of true positives, true negatives, false negatives, and false positives diagnosed by MRE were screened; next, the diagnostic accuracy, sensitivity, and specificity of MRE in assessing active CD were calculated. RESULTS: Of the 48 patients, 39 were diagnosed with small bowel CD by MRE, which was not significantly different from the results of enteroscopy (P>0.05). According to MRE diagnostic results, the arterial phase predominantly presented high signal intensity, and the venous phase mainly presented low signal intensity or isointensity. Small bowel CD lesions were primarily characterized by bowel wall thickening, rare pneumatosis enhancement of the bowel wall, bowel lumen pneumatosis or dilatation, and rare strictures. Besides, MRE presented an accuracy of 93.75%, sensitivity of 97.37%, and specificity of 80.00% in diagnosing CD. CONCLUSION: 3.0 T MR imaging has diagnostic value for active CD and shows certain clinical application value.

[Diagnosis value of 3.0 T diffusion-weighted imaging with background suppression magnetic resonance for metastatic lymph nodes in rectal cancer].

OBJECTIVE: To evaluate the diagnostic value of 3.0 T diffusion-weighted imaging with background suppression (DWIBS) magnetic resonance (MR) for lymph node metastasis in rectal cancer. METHODS: Thirty-five patients with rectal cancer who underwent preoperative routine MRI+DWI examination were enrolled in the study and were treated by rectal cancer resection plus lymph node dissection. Metastatic and non-metastatic lymph nodes were confirmed by postoperative pathology. Apparent diffusion coefficient (ADC) values, long-axis and short-axis diameters of lymph nodes were measured. Receiver operating characteristic (ROC) curve was used to assess the diagnostic efficacy of ADC, long-axis and short-axis diameters for differentiating metastatic lymph nodes from non-metastatic lymph nodes. RESULTS: A total of 151 lymph nodes were confirmed with exact location in 35 patients. Sixty-five metastatic lymph nodes and 86 non-metastatic lymph nodes were identified. The ADC values of metastatic lymph nodes and non-metastatic lymph nodes were(0.86±0.14)×10(-3) and (0.94±0.16)×10(-3) mm(2)/s respectively. The long-axis diameter were(9.78±3.13) and (7.90±1.77) mm, respectively. The short-axis diameter were (7.65±2.00) and (6.45±1.19) mm, respectively. There were statistically significant differences between metastatic and non-metastatic lymph nodes in ADC values, long-axis diameter, and short-axis diameter(all P<0.01). The areas under the ROC curve of ADC value, long-axis diameter, and short-axis diameter were 0.648, 0.706, and 0.692, respectively. Optimal cutoff values for these parameters were 1.05×10(-3) mm(2)/s, 7.95 mm, and 5.90 mm, respectively, and the corresponding sensitivities and specificities were 93.8% and 30.2%, 75.4% and 61.6%, 90.8% and 38.4%. CONCLUSIONS: Quantitative measurement of ADC value may reflect the degree of diffusion restriction of metastatic lymph nodes by DWIBS at 3.0 T MR. Accurate diagnosis of metastatic lymph nodes in rectal cancer demands comprehensive evaluation combining ADC value with diameter measurement.

Differential diagnosis of metastasis from non-metastatic lymph nodes in cervical cancers: pilot study of diffusion weighted imaging with background suppression at 3T magnetic resonance.

BACKGROUND: Diffusion weighted imaging with background suppression (DWIBS) is potentially useful in detecting metastatic lymph nodes. This study aimed to evaluate the efficacy of DWIBS at 3T magnetic resonance (MR) for diagnosing metastatic lymph nodes in cervical cancer. METHODS: This retrospective study included 25 patients with cervical cancer who underwent MR examination and were treated by hysterectomy and lymphadenectomy. The metastatic and non-metastatic lymph nodes were histologically proven by operation. Apparent diffusion coefficient (ADC) values, long-axis diameters, short-axis diameters, ratio of short- to long-axis diameters of all the identifiable lymph nodes were measured and compared. RESULTS: Twenty-five primary tumor lesions, 17 metastatic lymph nodes and 140 non-metastatic lymph nodes were pathologically confirmed in 25 cases with cervical cancer. The difference of ADC values between primary tumor lesions, metastatic and non-metastatic lymph nodes were statistically significant (F = 7.93, P = 0.001). There was no statistically significant difference between primary tumor lesions of cervical cancer and metastatic lymph nodes (t = -0.75, P = 0.456), and the difference between primary tumor lesions and non-metastatic lymph nodes was statistically significant (t = 4.68, P < 0.001). The ADC values, long-axis diameters, short-axis diameters, ratio of short- to long-axis diameters of metastatic and non-metastatic lymph nodes were (0.86 ± 0.36) × 10(-3) mm(2)/s vs. (1.12 ± 0.34) × 10(-3) mm(2)/s, (1.51 ± 0.41) cm vs. (1.19 ± 0.36) cm, (1.16 ± 0.35) cm vs. (0.77 ± 0.22) cm, 0.78 ± 0.17 vs. 0.68 ± 0.19 respectively, and statistically significant difference existed between two groups. CONCLUSIONS: DWIBS at 3T MR has the distinct advantages in detecting pelvic lymph nodes of cervical cancer. Quantitative measurement of ADC values could reflect the degree of restriction of diffusion of metastatic and non-metastatic lymph nodes. The combination of size and ADC value would be useful in the accurate diagnosis of metastatic lymph nodes.