RESULTS: In addition to the medical history, physical examination and laboratory tests, abdominal ultrasonography should be performed to establish the diagnosis (and sometimes computed tomography [CT]

The gap

Consensus across the literature

Supporting evidence — 4 representative gaps

• The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of colorectal cancer, 2024 update (2024) · doi

  Contrast-enhanced upper abdominal USh Abbreviations: CA199, carbohydrate antigen 199; CEA, carcinoembryonic antigen; CT, computed tomography; MRI, magnetic resonance imaging; US, ultrasound. aColonoscopy is generally prohibited in patients with clinically evident intestinal obstruction, as bowel preparation before the examination may exacerbate the obstruction or cause perforation. bA digital rectal exam can provide specific clinical signs of whether there are tumor lesions in the pelvic floor, which is a specific clinical sign of peritoneal metastasis. cFor patients who are not eligible, who refuse a full colonoscopy, or whose colonoscopy cannot examine the entire colon, it is recommended to perform a contrast- enhanced abdominal/pelvic CT scan after bowel cleansing. dContrast-enhanced chest CT is recommended for diagnosis and differential diagnosis of metastatic lymph nodes. Continuous thin-section axial, coronal, and sagittal reconstructed images are recommended for diagnosis and differential diagnosis of pulmonary metastases from colorectal cancer wherever possible [19]. Enhanced abdominal and pelvic CT is recommended for diagnosis of ovarian metastases and peritoneal metastases. eFor patients with contraindications to venous contrast, it is recommended to perform contrast-enhanced abdominal/pelvic MRI plus non-contrast-enhanced chest CT. fWhen the diagnosis of ovarian metastasis cannot be confirmed by CT, pelvic MRI or gynecologic ultrasound is recommended to support the diagnosis, and MRI is recommended to include T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and multi-phase T1-weighted enhanced imaging sequences [20]. gWhen the diagnosis of liver metastases cannot be confirmed by CT or when treatment decisions for liver metastases need to be changed, liver MRI including T2WI, DWI, and multi-phase T1-weighted enhanced imaging sequences is recommended to determine the number, size, and distribution of liver metastases. Eligible patients may directly choose Hepatocyte-specific contrast-enhanced liver MRI, which is more helpful in detecting lesions smaller than 1 cm, especially metastases that cannot be visualized by CT after chemotherapy [21, 22]. hFor eligible patients, contrast-enhanced liver ultrasound or contrast-enhanced intraoperative ultrasound can be performed to further clarify the diagnosis of liver metastases, especially metastases that cannot be visualized by CT after chemotherapy [22]. PET/CT can be used to detect potential metastases when there is clinical suspicion of metastasis that cannot be confirmed by other imaging examinations, or before major treatment decisions are made (e.g., when there is a possibility of curative treatment in recurrent metastatic patients), thus helping to avoid overtreatment [23]. How- ever, PET/CT is not recommended as a routine test for the diagnosis of colorectal cancer. 2.2.2. Diagnosis methods for rectal cancer

  Keywords: enhanced diagnosis metastases recommended contrast liver imaging patients cannot pelvic abdominal ultrasound weighted specific clinical
• The Chinese Society of Clinical Oncology (CSCO): Clinical guidelines for the diagnosis and treatment of colorectal cancer, 2024 update (2024) · doi

  Contrast-enhanced upper abdominal ultrasoundj Abbreviations: CA199, carbohydrate antigen 199; CEA, carcinoembryonic antigen; CT, computed tomography; MRI, magnetic resonance imaging; US, ultrasound. aColonoscopy is generally prohibited in patients with clinically evident intestinal obstruction, as bowel preparation before the examination may exacerbate the obstruction or cause perforation. bAlthough it cannot serve as diagnostic evidence, it’s emphasized that clinicians should perform digital rectal exams on all patients with suspected rectal cancer. cFor patients who are not eligible, who refuse a full colonoscopy, or whose colonoscopy cannot examine the entire colon, it is recommended to perform a contrast- enhanced abdominal/pelvic CT scan after bowel cleansing. dHigh-resolution pelvic MRI is the optimal imaging method for diagnosing rectal cancer with cT3 and higher stages, cN stages, mesorectal fascia, extramural vascular invasion, and anal canal structures [24]. Both rectal endoscopic ultrasound and MRI are superior to CT for cT staging of rectal cancer, and rectal endoscopic ultrasound is better than MRI in the diagnosis of cT2 and lower-stage disease [25]. eWhen patients have contraindications for MRI scanning, non-contrast and contrast-enhanced pelvic CT is recommended. fContrast-enhanced chest CT is recommended for diagnosis and differential diagnosis of metastatic lymph nodes. Continuous thin-section axial, coronal, and sagittal reconstructed images are recommended for diagnosis and differential diagnosis of pulmonary metastases from colorectal cancer wherever possible [19]. Enhanced abdominal and pelvic CT is recommended for diagnosis of ovarian metastases and peritoneal metastases. gFor patients with contraindications to venous contrast, it is recommended to perform contrast-enhanced abdominal/pelvic MRI plus non-contrast-enhanced chest CT. hWhen the diagnosis of ovarian metastasis cannot be confirmed by CT, pelvic MRI or gynecologic ultrasound is recommended to support the diagnosis, and MRI is recommended to include T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and multi-phase T1-weighted enhanced imaging sequences [20]. iWhen the diagnosis of liver metastases cannot be confirmed by CT or when treatment decisions for liver metastases need to be changed, liver MRI including T2WI, DWI, and multi-phase T1-weighted enhanced imaging sequences is recommended to determine the number, size, and distribution of liver metastases. Eligible patients may directly choose liver-specific contrast agent-enhanced MRI, which is more helpful in detecting lesions smaller than 1 cm, especially metastases that cannot be visualized by CT after chemotherapy [21, 22]. jFor eligible patients, contrast-enhanced liver ultrasound or contrast-enhanced intraoperative ultrasound can be performed to further clarify the diagnosis of liver metastases, especially metastases that cannot be visualized by CT after chemotherapy [22]. PET/CT can be used to detect potential metastases when there is clinical suspicion of metastasis that cannot be confirmed by other imaging examinations, or before major treatment decisions are made (e.g., when there is a possibility of curative treatment in recurrent metastatic patients), thus helping to avoid overtreatment [23]. How- ever, PET/CT is not recommended as a routine test for the diagnosis of colorectal cancer. 2.2.3. Diagnosis methods for rectal-anal cancer 2.2.3.1. Content of rectal-anal cancer imaging diagnosis

  Keywords: diagnosis enhanced contrast recommended metastases imaging patients rectal cannot cancer liver ultrasound pelvic abdominal weighted
• MRI versus histopathology in EMVI detection for rectal cancer: prognostic relevance and survival outcomes (2026) · doi

  Key Points Question Reliable preoperative markers are lacking for accurate EMVI detection in rectal cancer, creating uncertainty in risk stratification and treatment decisions due to inconsistent MRI–pathology concordance.

  Keywords: points question reliable preoperative markers lacking accurate emvi detection rectal cancer creating uncertainty risk stratification
• Acute Appendicitis in Childhood and Adulthood: An Everyday Clinical Challenge (2020) · doi

  RESULTS: In addition to the medical history, physical examination and laboratory tests, abdominal ultrasonography should be performed to establish the diagnosis (and sometimes computed tomography [CT] or magnetic resonance imaging [MRI], if ultrasonography is insufficient).

  Keywords: ultrasonography addition medical history physical examination laboratory tests abdominal performed establish diagnosis sometimes computed tomography