What is the best test to identify prostate enlargement and prostate cancer? This is a common disease in elderly patients, and the prognosis for early prostate cancer is very good after diagnosis and treatment. The general method to differentiate between cancer and hyperplasia is: rectal examination and prostate specific antigen (PSA) test, and puncture biopsy for suspicious cases. The problem, however, is that early, i.e. very small, tumors that occur inside the prostate rather than at the margin are not well detected by finger palpation; and increased PSA values, in addition to cancer, are also higher than normal in some patients with prostate enlargement. Therefore, the reliance on imaging is self-explanatory. So, which imaging test is effective and sensitive to choose? Doctors recommend many methods: ultrasonography, CT, MRI, PET-CT, etc. There are also patients who say, “I’ve had an MRI, but how come the diagnosis is still not certain? Ultrasonography is generally not sensitive to the identification of prostate enlargement and cancer. It is especially difficult to detect very small tumors, especially since many ultrasound doctors recommend other tests once they find an enlarged prostate, and if they are not sure of the identification, they simply recommend “further tests”. The most important thing is that you can get the correct diagnosis by using a more detailed examination, such as transrectal ultrasound, which is more sensitive to the lesion than abdominal ultrasound. In ultrasonography, cancer foci can have different echogenic characteristics, but when the infiltration of the cancer foci has no obvious boundary or the gray scale difference between the tumor and the surrounding prostate tissue is too small, both sonograms are more difficult to detect, and small lesions are more likely to be missed. The observation of blood flow characteristics in the area of the lesion is also an advantage of ultrasound, and a more common method is to use biopsy of the lesion under ultrasound guidance for suspicious lesions. This shows that ultrasound can be used as a screening test for prostate lesions; or to do a puncture biopsy of the lesion using ultrasound guidance. It is not sensitive to the detection of some atypical or small cancerous lesions. CT examination: CT scan is mainly to observe whether the prostate gland is enlarged or not and whether there are abnormal lymph nodes in the pelvis, simple scan has no greater application value. Using CT to diagnose prostate cancer mainly relies on dynamic enhancement examination (non-dynamic ordinary enhancement examination is generally of no more value except for advanced cancer) to observe the blood supply characteristics of the lesion area to diagnose whether it is a cancerous lesion or hyperplasia. However, its information is more homogeneous. MRI (magnetic resonance imaging) is the most effective and sensitive test for prostate cancer detection and differentiation from prostate hyperplasia. As mentioned earlier, some patients have had MRI done, but how can the diagnosis still not be determined? This is also depends on whether the MRI done is standardized or not, unstandardized exams can still cause diagnostic difficulties. The requirements for routine MRI of the prostate are: T2WI compression lipid axial, coronal (plus sagittal if necessary); T1WI axial; DWI; 6 or 8 phase dynamic enhancement scan. In total, thousands of images have to be acquired. If the diagnosis is still difficult, magnetic resonance spectroscopy (MRS) is added, which is not necessary in most cases. It is easier to make a diagnosis by following only the routine tests described above. In addition, for prostate abscesses MR also has its own characteristics and is easily distinguished from cancerous foci. PET-CT (PET CT): FDG-PET/CT is widely used in the early diagnosis of many tumors (i.e., using 18F as a tracer, which is used in most hospitals because it is easy to get), especially on lung cancer, esophageal cancer, head and neck cancer and primary breast cancer, but prostate cancer has a slower growth rate and less glucose utilization, so the FDG The uptake rate of FDG is low, and the difference in FDG uptake rate between malignant lesions and normal prostate tissue, and foci of prostate inflammation is not significant, so FDG-PET/CT is not suitable for diagnosing early prostate cancer. It has been suggested that the total sensitivity, specificity and accuracy of 11C-choline PET/CT are 96.6%, 76.5% and 93.3%, respectively. However, the short half-life of 11C-choline averages 20 minutes, which limits the application to early prostate cancer, and the uptake of 11C-choline PET/CT to other lesions of the prostate such as inflammation is also high and not easily distinguished from cancer. Therefore, C-11-choline cannot be used as a routine first-line screening method, but can be used as a second-line screening tool. In conclusion, this method is mainly used to examine the metastases of prostate cancer, especially bone metastases, and is less suitable for the first choice examination for the diagnosis of prostate cancer. The above brief description of several imaging methods shows that MRI still has the advantage and should be the first choice for the differentiation of prostate cancer from hyperplasia and the detection and diagnosis of small cancer foci.