ABSTRACT
Although Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) is routinely used in oncological imaging, the F-18 fluorodeoxyglucose (18F-FDG) avidity is not tumor-specific. Numerous benign infective and inflammatory processes may also show increased radiotracer activity. Similarly, abnormal 18F-FDG uptake in an inflamed appendix can pose a diagnostic challenge for the interpreter of oncologic 18F-FDG PET/CT. We present the case of an 18-year-old female with classic Hodgkin's lymphoma who had 18F-FDG PET/CT while undergoing chemoradiotherapy. The scan demonstrated a complete metabolic response to treatment. However, there was increased 18F-FDG uptake in the right iliac region, projecting over the appendix, which, if interpreted as a lymphomatous involvement, would have upscaled the treatment response to progressive disease. The patient was called for additional workup, which included an ultrasound abdomen. The scan revealed classic features of acute appendicitis. However, there was no appendicolith or luminal obstruction. Upon additional questioning, the patient mentioned mild intermittent abdominal pain and anorexia eased by pain relievers for the preceding few days. On deep palpation of her abdomen, there was rebound tenderness in the right iliac region. According to the Alvarado score, it was graded 7 points suggesting probable/likely appendicitis. After collective evaluation of the clinical, laboratory, and imaging findings, the appendicular 18F-FDG uptake was deemed secondary to uncomplicated acute appendicitis rather than a lymphomatous lesion. Our patient refused surgery as she did not have severe abdominal pain. She was hemodynamically stable without signs of luminal obstruction. She was non-operatively managed with broad-spectrum antibiotics for six days. The results of the follow-up complete blood counts and ultrasound examination were negative. Our patient was symptom-free and recovering normally at a two-week follow-up appointment. We present a follow-up case of classic Hodgkin's lymphoma with incidental uptake in the appendix, which resembled submucosal lymphomatous cell infiltration of the appendix. Careful scrutiny, clinical correlation, physical examination, blood tests, and additional imaging offered helpful insight and led to the correct, benign diagnosis of the 18F-FDG avid appendix.
ABSTRACT
18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been established as the indisputable tool in the oncological arena to diagnose, stage/restage, and report treatment response for various tumor malignancies. FDG uptake mostly identifies pathological uptake in oncological scans with the tracer on PET studies; however, benign uptakes are also commonly seen. Reported here is a benign case of increased uptake of the FDG on a PET with computed tomography scan in the gallbladder (GB) of a patient being screened for a known carcinoma breast. The benign accumulation of the tracer is seen in the GB to various degrees and this phenomenon may occur as a result of FDG excretion into the bile. When interpreting clinical PET images, recognition of this phenomenon is important to avoid misdiagnosing physiological GB FDG uptake as pathological so as to avoid misinterpretations of the findings.
ABSTRACT
Introduction Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) is used for non-invasive staging and restaging of solid malignant tumors. PET-CT based criteria have been developed to evaluate the response to targeted therapy. These include the European Organization for Research and Treatment of Cancer (EORTC) and the PET Response Criteria in Solid Tumors (PERCIST). The aim of this study was to determine the agreement between EORTC and PERCIST criteria for treatment response evaluation in patients with solid malignant tumors. Materials and methods This was a retrospective study conducted from February 2017 till July 2017. Electronic medical records of patients diagnosed with solid malignant tumors were searched. Experienced radiologists evaluated the PET-CT images based on EORTC and PERCIST criteria. The Kappa (κ) test was used for evaluation of agreement between treatment response according to EORTC and PERCIST criteria. Results Out of 54 patients, 41 (75.9%) were male and 13 (24.1%) were female with a mean age of 57.09 ± 10.65 years. According to EORTC criteria, complete metabolic response (CMR) was seen in five (9.3%) of patients, partial metabolic response (PMR) was seen in 36 (66.7%) of patients, progressive metabolic disease (PMD) was seen in nine (16.7%) of patients and stable metabolic disease (SMD) was seen in four (7.4%) of patients. According to PERCIST criteria, CMR was seen in five (9.3%) of patients, PMR was seen in 33 (61.1%) of patients, PMD was seen in nine (16.7%) of patients and SMD was seen in seven (13.0%) of patients. EORTC and PERCIST agreed on 43 (79.6%) of the patients with κ-coefficient of 0.62 indicating good agreement (p-value of <0.001). Conclusion EORTC and PERCIST criteria have a good agreement in evaluating treatment response in solid malignant tumors. Therefore, adoption of EORTC or PERCIST in PET-CT reporting can standardize the evaluation of oncological treatment results.
ABSTRACT
OBJECTIVE: To determine the success rate and complication of CyberKnife Robotic Radiosurgery for treating intracranial and extra cranial tumours. METHODS: The cross-sectional observational study was carried out at the Department of CyberKnife Robotic Radiosurgery at the Jinnah Postgraduate Medical Centre, Karachi, and reviewed data related to a year from December 2012 to December 2013. Patients referred from different hospitals within and outside Pakistan for stereotactic radiosurgery were included. The patients had benign tumours less than 7cm size, post-operative residual tumour and recurrent tumour with post-radiotherapy. Patients were followed up every three months with contrast magnetic resonance imaging. Radiosurgery was considered successful if patients improved clinically with radiologically stable disease or if there was interval reduction in the size of tumour. SPSS 17 was used for data analysis. RESULTS: Initially, 260 patients were selected, but 9(3.5%) were lost, and the final sample size was 251(96.5%). Clinically successful outcome results were seen in 225(90%) patients, while 8(3%) showed no change in symptoms and 18(7%) patients' follow-up is awaited. Radiological improvement was noted in 218(87%); stable disease in 138(55%) and 80(32%) cases showed more than 30% reduction in size after 6-12 months of follow-up. Only 5(2%) cases showed subtle increase in size within 3-month interval due to post-radiation oedema. Acute transient post-radiation changes were seen in 25(10%) patients, sub-acute changes in 4(1.59%) and 1(0.3%) patient showed radionecrosis after 9-month interval. CONCLUSIONS: Cyberknife was an effective, safe and successful treatment alternative to surgery in benign and malignant tumours with low risk of post-radiotherapy complication compared to conventional radiation.
