I. Neurological system.
MRI is suitable for the examination of various cranio-cerebral diseases. Except for skull fracture fractures, confirmation of a small amount of calcification and certain acute cerebral hemorrhagic diseases that require reference to CT for diagnosis, MRI is able to make correct diagnosis for the vast majority of congenital dysplasia or malformations of the skull and brain, brain tumors, cerebrovascular disease, cranio-cerebral injuries, brain degenerative diseases, cerebral white matter disease and inflammatory brain diseases.
MRI is usually very sensitive in detecting brain lesions, but the qualitative diagnosis of some diseases still needs to be considered in close conjunction with clinical data.
Stroke, leukoencephalopathy, craniocerebral injury, and other diseases often have different pathological changes and MRI manifestations depending on the time of onset. Therefore, complete clinical information, especially the length of time between the onset of the disease and the time of MRI examination, is necessary to improve the correctness of MRI diagnosis. It is recommended that the application form be filled out with the exact time between the onset of the disease and the time of filling out the application form, rather than just a simple complaint. In addition, the provision of brief and accurate neurological signs can enable the imaging physician to make a more accurate qualitative diagnosis of intracerebral disease.
MRI has gained wide acceptance for the diagnosis of spinal and spinal cord disorders. Degenerative spinal lesions, trauma to the spine and spinal cord, tumors in the vertebrae and spinal canal, inflammation of the spine and spinal cord, congenital malformations of the spine and spinal cord (including combined craniocervical malformations), and vascular lesions in the spinal canal are all indications for MRI examination, and MRI can diagnose most of these lesions both locally and qualitatively. However, for the observation of subtle trabecular changes, such as vertebral plate fractures and sand-like dead bone of spinal tuberculosis, it is still better to combine with CT for diagnosis. According to our experience over the years, some patients with lumbar and leg pain who have herniated and bulging discs on CT examination may not necessarily have herniated discs as their true cause, and further MRI examination is advisable for suspicious patients to delay misdiagnosis and mistreatment.
Since the spine itself includes a long range, a full spine MRI examination requires three sites to complete, therefore, the correct positioning of the suspected lesioned segment of the spine before MRI examination is an effective way to make patients spend less money and get better. It is recommended that spine MRI exams be performed by a spine specialist, neurologist, or neurosurgeon and carefully localized before the exam.
As with intracerebral lesions, the qualitative diagnosis of intravertebral lesions, especially those in the spinal cord, also requires close integration with clinical data, and the MRI manifestations of the disease are closely related to the time of onset.
Bone, joint and muscle.
MRI has unique advantages for the examination of the bone and joint system. The main reason for this is that MRI can reflect pathological changes within cartilage, paracondylar soft tissue and bone marrow.
MRI is currently the best method for in vivo diagnosis of cartilage diseases. MRI is very good at showing congenital abnormalities in cartilage development, degeneration (early degenerative osteoarthropathy), destruction (such as early recognition of articular cartilage destruction by various joint inflammatory diseases) and trauma. The sensitivity, specificity and accuracy of MRI are very high (close to 95%), and the false negative and false positive rates are low (less than 5%), and MRI may also show some lesions that cannot be shown by arthroscopy. MRI is currently considered to be the imaging method of choice for meniscal tears.
MRI is the best way to directly show muscle, tendon, and ligament tears, and its ability to diagnose bone marrow lesions such as bone marrow edema, bone marrow contusions, and bone marrow tumor infiltration allows it to detect many diseases that were previously undetectable by imaging, determine whether fractures are old, and make a more correct diagnosis of skeletal disease months before trabeculae are destroyed.
MRI is valuable for the early diagnosis of osteomyelitis, as the foci of osteomyelitis appear as obvious high-signal areas on fat-suppressed T2WI, and MRI can well identify and confirm the extent of osteomyelitis involving extraosseous soft tissues (e.g., subperiosteal abscesses).
MRI can evaluate the spatial characteristics and biological behavior of bone tumors and tumor-like lesions from multiple directions and factors. Its imaging characteristics determine that it can highlight changes in bone marrow signals in signal-free bone structures, and can easily detect areas of lesions with bone marrow invasion but preserved bone trabecular structures, and can clearly distinguish lesions, perifocal edema, and normal bone marrow tissue. However, because benign and malignant tumor tissues do not correspond to specific MRI signals, and MRI does not have particular advantages in signal display and morphological description of ossification and calcification, the qualitative diagnosis of bone tumors by MRI should be closely combined with CT or plain film signs.
III. Heart.
MRI can correctly evaluate various lesions of the heart and blood vessels. Precardiac disease, various acquired cardiomyopathies, valvular disease, pericardial lesions, and cardiac tumors can be correctly diagnosed by MRI. Direct MRI, non-enhanced MRA, and enhanced MRA are able to evaluate vessel vessel size, vessel wall, and lumen contents. Enhanced MRA is better than non-enhanced MRA in terms of the accuracy of showing the size of the vessel lumen and its contents.
IV. Abdomen and pelvis.
MRI has advantages over ultrasound and CT in the diagnosis of abdominal lesions, because it has better soft tissue contrast and can often detect small lesions in parenchymal organs such as the liver, pancreas, spleen, and kidney and can help characterize lesions by detecting or confirming some tissue types. MRI is often superior to other methods for the localization and characterization of larger intra-abdominal lesions because of its inherent ability to show the characteristics of the lesion in multiple directions and factors.
MRI water imaging is well established in the abdomen and can be performed non-invasively and perfectly for pancreaticobiliary water imaging, kidney, ureter, bladder and urinary tract water imaging, and intestinal water imaging.
MRI can show the uterus, ovaries, prostate, rectum, bladder and other structures well. The following intrapelvic diseases are suitable for MRI examination.
① Abnormal sexual differentiation and congenital anomalies of the female genital tract.
(2) benign lesions of the cervix and staging of cervical cancer; benign and malignant tumors of the uterine body and preoperative staging of cancer; various types of ovarian cysts, benign hyperplasia and benign and malignant tumors; and endometriosis in the pelvis.
MRI can directly display the ovaries and follicles, and its sensitivity is significantly better than CT and ultrasound in the display of ovarian cysts and polycystic ovaries. In terms of characterization, MRI is significantly better than ultrasound and CT, especially in the diagnosis of endometriosis and teratoma and in identifying tumor recurrence and fibrosis.
③Non-invasive measurement of the bony birth canal, intrauterine fetal growth retardation and malformation, abnormal placental position and determination of the presence or absence of placental abruption and infarction, and staging of gestational trophoblastic tumors.
④ Inflammation of male genital organs, benign and malignant tumors and congenital anomalies. MRI is an optimal diagnostic imaging tool in the display and staging of prostate cancer. Prostate wave spectrum analysis technique is more advantageous in differentiating prostate cancer from prostate hyperplasia and prostate inflammation.
⑤ Benign and malignant tumors of the bladder and rectum and staging; preoperative and postoperative evaluation of congenital atresia of the anal canal.
V. Five senses.
MRI can clearly show the morphology of the eye, ear, nose and throat and their structures. It is adapted to evaluate the eye, eye muscle, optic nerve and intraorbital lesions, and is particularly suitable for evaluating the site and extent of brain-related lesions. However, MRI is not indicated for intraocular or orbital metal abnormalities.
MRI can clearly display tumors smaller than 5 mm in the internal auditory canal, and water imaging can show the three-dimensional pattern of the inner ear membrane vagus containing endolymphatic fluid. MRI has advantages that other examinations do not have for diagnosing tumors in the nasopharynx and five sensory areas and their relationship with the skull base and brain. MRI is simple, intuitive and accurate for the display of paranasal sinus inflammation.
VI. Thorax.
The advantage of MRI for thoracic and pulmonary examinations is its ability to directly display the vascular structures in the mediastinum and hilum, which helps to comprehensively evaluate the relationship between the lesion and the mediastinum and hilum and the staging of the lesion. However, it is generally believed that MRI is not as good as CT for the overall evaluation of intrapulmonary disease.
The value of MRI for mammography is to.
① Evaluating the breast before biopsy and reducing the number of surgical biopsies of benign lesions. This is because breast cancer is characterized by sustained enhancement in enhanced MRI, whereas benign lesions do not have contrast enhancement.
②Staging of breast cancer. It can show small multicentric nodular foci that cannot be shown by mammogram or ultrasound, and the tumor extent determined by MRI correlates well with the extent of pathological examination.
③Evaluate breast cancer that is not clearly diagnosed by conventional imaging.
④MRI-guided interstitial laser coagulation therapy.
⑤ Evaluate the integrity of silicone implants.