2018 Vol. 42, No. 4
PET/MR is the most advanced molecular imaging device nowadays. The PET image needs to be quantified by attenuation correction(AC) to obtain the real activity distribution of radioactive drugs. The principle of AC of PET/MR and four methods of AC are briefly described in this paper.This paper mainly introduces the tissue segmentation and atlas method. A more promising launch data reconstruction method is also introduced in this paper.
In recent years, the clinical application of the precise molecular targeted therapy and immunotherapy of lung cancer has been a focus of lung cancer research. 8F-FDG PET/CT is an imaging technology that merges morphology and molecular metabolism. 18F-FDG PET/CT can provide timely information about the activities of tumor cells compared with traditional imaging technologies, such as CT and MRI, and has significant value on guiding precise radio-chemotherapy and monitoring treatment efficacy in lung cancer. This article will focus on the application of 8F-FDG PET/CT in lung cancer, particularly in the delineation of targeted lesion, evaluation of treatment effect, and prognosis evaluation.
Medical imaging plays an important role in the clinical staging, restaging, and therapy assessment of tumors and may also serve as prognostic biomarker. Multimodal hybrid imaging technologies, such as PET/CT and recently PET/MR, have been rapidly developed in recent years. PET/CT is often recommended for the initial staging of FDG-avid lymphomas and therapy monitoring. The role of FDG PET/CT for interim therapy evaluation must be determined. Some feasibility studies indicated that using PET/MR for initial lymphoma staging is feasible. FDG PET/MR seemed to offer a comparable diagnostic performance compared with PET/CT. In this article, the research status and progress concerning multimodal hybrid imaging technologies, such as PET/CT and PET/MR, in malignant lymphoma are reviewed.
Midkine (MK) has multiple biological functions, and plays an important role in the diagnosis and treatment of tumor. Midkine is generally overexpressed in diverse malignant tumors, and enhances proliferation, migration and angiogenic activity of tumor cells. Recent studies have found that MK is closely related with thyroid cancer. Immunohistochemical studies showed that MK expression in thyroid cancer cells and tissues was significantly higher than that of normal thyroid. MK level of the needle aspiration eluant had a good diagnostic value for the differentiationbetween benign and malignant thyroid nodules. MK is cytokinesecreted in the blood; it could be used as a serological marker for the differentiation between benign and malignant thyroid nodules. MK could also beapplied for the prognosis of differentiated thyroid carcinoma treated by 131I (whether with or without metastases). In addition, in the case of thyroglobulin antibody positivity, MK could be surrogated as a viable serological marker for predicting thyroid cancer metastasis. The major limitation of MK is lowoncological specificity. In many cases, it is necessary to measure MK with other specific tumor markers. Future researches should focus on the mechanism of MK in the occurrence, development and therapeutic resistance of thyroid cancer. This review discusses the value of MK as a thyroid cancer marker.
The author reports a case of small cell carcinoma of the cervix. The patient had a 7-day history of headache and a hard mass in the parietal region of the cranium on the right side as the first manifestation. Cranial CT scan showed a high-density nodule on the right parietal lobe, with a surrounding low-density edema and adjacent skull bone destruction; thus, intracranial tumor was considered. MRI brain scan showed a slightly longer T1 and T2 signal nodule, with edema in the right parietal lobe. The lesion was significantly enhanced after the application of contrast. The 18F-FDG PET/CT whole-body imaging showed a solid mass of cervix and slightly large bilateral pelvic lymph nodes and presented multiple bone destruction with high FDG uptake. The histopathological examination revealed small cell carcinoma of the cervix. Small cell carcinoma of the cervix has extremely low incidence, its clinical manifestation lacks specificity, and it is not easily detected at its early stage. Small cell carcinoma of the cervix is an aggressive tumor and commonly have early metastasis through lymph node and blood circulation, with a poor prognosis. The sensitivity of 18F-FDG PET/CT in detecting primary lesions and metastases, including lymph node, bone, and other occult lesions, is high. Thus, this method is valuable in the clinical management of the small cell carcinoma of the cervix.
The present case describes the 99Tcm-DTPA renal dynamic imaging of bilateral extrarenal pelvis accompanied by severe hydronephrosis of the left pelvis. The extrarenal pelvis is usually asymptomatic and is often found through abdominal examination via abdominal ultrasonography or CT scan. Hydronephrosis generally does not compress the renal cortex because the renal pelvis is located outside the kidney; thus, the patient's early serum urea and creatinine levels are normal or slightly increased. 99Tcm-DTPA renal dynamic imaging is the clinicians' first choice for evaluating left or right renal functions. Bilateral extrarenal pelvis, accompanied by severe hydronephrosis of pelvis, presents an abnormal concentration of 99Tcm-DTPA outside the renal area. This abnormality needs to be identified as urinary leakage or renal dysplasia. Therefore, we explored the characteristics of 99Tcm-DTPA renal dynamic imaging and the differential diagnosis of extrarenal pelvis with severe hydronephrosis in this study. Understanding this anatomical variation and providing information about renal functions can help clinicians make appropriate clinical decisions and reduce the risk of damage in the renal pelvis during surgery.
Among mediastinal tumors, thymoma, neurogenic tumors, lymphomas and germ cell tumors are more common. The clinical manifestations of mediastinal tumor vary according to tumor size, site and benign and malignant. Mediastinal tumor in children is common in clinical, with no typical early symptoms, lack of specificity, and generally increases with tumors appeared some symptoms such as chest pain, dyspnea, cough, so early diagnosis is difficult. Two cases of mediastinal mass in children without specific clinical symptoms were selected, through its 18F-FDG PET/CT imaging features and clinical data for the differential diagnosis, summarize the diagnosis idea, in order to improve the imaging diagnostic accuracy.