F-18 FDG PET/CT for detection of malignant involvement of peripheral nerves: case series and literature review.

PURPOSE: To evaluate the role of positron emission tomography plus computed tomography (PET/CT) scans in detecting malignant involvement of the peripheral nerves (PNs). MATERIAL AND METHODS: We retrospectively reviewed medical records of all PET/CT studies performed at The University of Texas MD Anderson Cancer Center between 2003 and 2009, and selected patients in whom F-18 fluorodeoxyglucose (FDG) PET/CT findings were suspicious for malignant involvement of the PNs. We identified 26 cases of suspected tumorous involvement of the PNs that was subsequently confirmed by either biopsy or clinical follow-up. We evaluated the value of PET/CT in diagnosing malignant involvement of the PNs. RESULTS: Of the 26 patients, 12 had lymphoma, 10 had breast cancer, 2 had lung cancer, 1 had colon cancer, and 1 had melanoma. In 21 patients, magnetic resonance imaging (MRI) was performed, either for follow-up of the PET/CT finding or to find an explanation for symptoms. MRI confirmed the presence of disease in only 9 patients, was interpreted as normal in 7 patients, and was inconclusive in 5 patients. FDG PET/CT was able to differentiate an active tumor from post-treatment fibrosis and could assess response to therapy with a high degree of confidence. CONCLUSIONS: Our results indicate that FDG PET/CT is helpful in diagnosing malignant involvement of the PNs, especially when findings from anatomic imaging (MRI or CT) are negative. In cases of known treated malignancy involving the PNs, follow-up by PET/CT has the advantage of high sensitivity for local recurrence

F-18 FDG PET/CT for Detection of Malignant Involvement of Peripheral Nerves Case Series and Literature Review

Purpose: To evaluate the role of positron emission tomography plus computed tomography (PET/CT) scans in detecting malignant involvement of the peripheral nerves (PNs). Material and Methods: We retrospectively reviewed medical records of all PET/CT studies performed at The University of Texas MD Anderson Cancer Center between 2003 and 2009, and selected patients in whom F-18 fluorodeoxyglucose (FDG) PET/CT findings were suspicious for malignant involvement of the PNs. We identified 26 cases of suspected tumorous involvement of the PNs that was subsequently confirmed by either biopsy or clinical follow-up. We evaluated the value of PET/CT in diagnosing malignant involvement of the PNs. Results: Of the 26 patients, 12 had lymphoma, 10 had breast cancer, 2 had lung cancer, 1 had colon cancer, and 1 had melanoma. In 21 patients, magnetic resonance imaging (MRI) was performed, either for follow-up of the PET/CT finding or to find an explanation for symptoms. MRI confirmed the presence of disease in only 9 patients, was interpreted as normal in 7 patients, and was inconclusive in 5 patients. FDG PET/CT was able to differentiate an active tumor from post-treatment fibrosis and could assess response to therapy with a high degree of confidence. Conclusions: Our results indicate that FDG PET/CT is helpful in diagnosing malignant involvement of the PNs, especially when findings from anatomic imaging (MRI or CT) are negative. In cases of known treated malignancy involving the PNs, follow-up by PET/CT has the advantage of high sensitivity for local recurrence

Radiologic manifestations of immune-related adverse events in patients with metastatic melanoma undergoing anti-CTLA-4 antibody therapy.

OBJECTIVE: Monoclonal antibodies against cytotoxic T-lymphocyte antigen 4 (CTLA-4) used for treatment of metastatic melanoma produce inflammatory immune-related adverse events. The purpose of the current study was to retrospectively identify and characterize the radiologic manifestations of immune-related adverse events and to evaluate the possible association between these events and clinical responses to anti-CTLA-4 therapy. MATERIALS AND METHODS: We retrospectively reviewed the images and medical records of 119 patients with metastatic melanoma treated with anti-CTLA-4 at our institution and assessed the presence of radiologic manifestations of immune-related adverse events and the clinical responses to therapy. The responses were categorized as progressive or controlled disease. The controlled disease category included stable disease, partial response, and complete response according to the Response Evaluation Criteria in Solid Tumors, version 1.1. RESULTS: Radiologic manifestations of immune-related adverse events were found in 20 patients (16.8%). Clinically evident manifestations included colitis, hypophysitis, thyroiditis, and arthritis. Clinically silent manifestations were benign lymphadenopathy and inflammatory changes in the soft tissues, such as myositis, fasciitis, and retroperitoneal fat haziness. There was a significant association between the incidence of radiologic manifestations of immune-related adverse events and clinical responses to anti-CTLA-4 therapy. The disease control rates were 18% for the entire group, 55% for the group with, and 10% for the group without radiologic manifestations of immune-related adverse events. In three patients (2.5%), lymphadenopathy related to radiologic manifestations of immune-related adverse events was interpreted as suspected metastasis but was proved benign at biopsy. CONCLUSION: Radiologic manifestations of immune-related adverse events are associated with significant clinical benefit of anti-CTLA-4 therapy. In the era of developing immune checkpoint-targeted therapy for metastatic melanoma, radiologists should be alert to the possibility of these manifestations, which can mimic radiologic disease progression

Evaluation of cancer treatment in the abdomen: Trends and advances.

Response evaluation in Oncology has relied primarily on change in tumor size. Inconsistent results in the prediction of clinical outcome when size based criteria are used and the increasing role of targeted and loco-regional therapies have led to the development of new methods of response evaluation that are unrelated to change in tumor size. The goals of this review are to expose briefly the size based criteria and to present the non-size based approaches that are currently applicable in the clinical setting. Other paths that are still being explored are not discussed in details

Abdominal and pelvic complications of nonoperative oncologic therapy.

Oncologic patients are treated with a combination of chemotherapy, radiation therapy, and surgery. Advances in therapeutic options have greatly improved the survival of patients with cancer. Examples of these advances are newer chemotherapeutic agents that target the cell receptors and advanced radiation therapy delivery systems. It is imperative that radiologists be aware of the variety of imaging findings seen after therapy in patients with cancer. Complications may occur with classic cytotoxic therapies (eg, 5-fluorouracil), usually at higher or prolonged doses or when administered to radiosensitive areas. Newer targeted systemic agents, such as bevacizumab and imatinib, have associated characteristic toxicities because their effects on cells do not depend on dose. Radiation may induce early and late effects in local normal tissues that may be seen at imaging. Imaging findings after chemotherapy include fatty liver, pseudocirrhosis, hepatic veno-occlusive disease, and splenic rupture. Complications of radiation therapy include large and small bowel strictures and radiation-induced hepatitis and tumors. Awareness of the various therapeutic options and knowledge of the spectrum of posttherapeutic complications allows radiologists to provide a comprehensive report that may impact patient management

PET/CT in the management of patients with stage IIIC and IV metastatic melanoma considered candidates for surgery: evaluation of the additive value after conventional imaging.

OBJECTIVE: The purpose of this article is to determine how often unexpected (18)F-FDG PET/CT findings result in a change in management for patients with stage IV and clinically evident stage III melanoma with resectable disease according to conventional imaging. SUBJECTS AND METHODS: Thirty-two patients with oligometastatic stage IV and clinically evident stage III melanoma were identified by surgical oncologists according to the results of conventional imaging, which included contrast-enhanced CT of the chest, abdomen, and pelvis and MRI of the brain. The surgical plan included resection of known metastases or isolated limb perfusion with chemotherapy. Thirty-three FDG PET/CT scans were performed within 36 days of their contrast-enhanced CT. The impact of PET/CT was defined as the percentage of cases in which a change in the surgical plan resulted from the unanticipated PET/CT findings. RESULTS: PET/CT revealed unexpected melanoma metastases in 12% of scans (4/33). As a result, the surgery was canceled for two patients, and the planned approach was altered for another two patients to address the unexpected sites. In 6% of scans (2/33), the unexpected metastases were detected in the extremities, which were not included in conventional imaging. Three scans (9%) showed false-positive FDG-avid findings that proved to be benign by subsequent stability or resolution with no therapy. CONCLUSION: In patients with surgically treatable metastatic melanoma, FDG PET/CT can detect unexpected metastases that are missed or not imaged with conventional imaging, and can be considered as part of preoperative workup

Measurement of Endotracheal Tube Positioning on Chest X-Ray Using Object Detection.

Patients who are intubated with endotracheal tubes often receive chest x-ray (CXR) imaging to determine whether the tube is correctly positioned. When these CXRs are interpreted by a radiologist, they evaluate whether the tube needs to be repositioned and typically provide a measurement in centimeters between the endotracheal tube tip and carina. In this project, a large dataset of endotracheal tube and carina bounding boxes was annotated on CXRs, and a machine-learning model was trained to generate these boxes on new CXRs and to calculate a distance measurement between the tube and carina. This model was applied to a gold standard annotated dataset, as well as to all prospective data passing through our radiology system for two weeks. Inter-radiologist variability was also measured on a test dataset. The distance measurements for both the gold standard dataset (mean error = 0.70 cm) and prospective dataset (mean error = 0.68 cm) were noninferior to inter-radiologist variability (mean error = 0.70 cm) within an equivalence bound of 0.1 cm. This suggests that this model performs at an accuracy similar to human measurements, and these distance calculations can be used for clinical report auto-population and/or worklist prioritization of severely malpositioned tubes