Comparison of (18F)FDG PET/CT and CT/MRI for the Diagnosis of Recurrent or Metastatic Disease after Treatment: In Head and Neck Cancer Patients

PURPOSE: We evaluated the accuracy of 18FFDG PET/CT for the detection of recurrence or metastasis after treatment in patients with primary head and neck cancer, and compared the results with those of CT/MRI. MATERIALS AND METHODS: We studied 34 patients with the diagnosis of head and neck cancer, who underwent treatment and follow up with 18FFDG PET/CT and CT/MRI. The patients were divided into two subgroups based on the difference in follow-up time interval and the type of treatment. Accuracy was evaluated by follow-up information and histopathology findings. The results of the 18FFDG PET/CT and CT/MRI were compared by statistical analysis. RESULTS: For the 18FFDG PET/CT results, 19 FDG uptake lesions were detected in 17 patients. Among these lesions, 18 were confirmed as recurrent or metastatic lesions and one as an inflammatory reaction from radiation therapy. Four lesions that had high FDG uptake were not detected by the CT/MRI. The sensitivity and specificity were 100% and 94.4% for the 18FFDG PET/CT and 77.8% and 94.4% for the CT/MRI (p<0.05). For the subgroup that received radiation therapy, 18FFDG PET/CT was more sensitive than CT/MRI (sensitivity = 100% vs. 63.6%, p<0.05). CONCLUSION: The results of this study showed that 18FFDG PET/CT was a useful screening modality for detecting recurrent or metastatic disease after treatment of patients with head and neck cancer, especially post-radiation.

CT Findings of Gastrointestinal Stromal Tumor versus Lymphoma of the Small Intestine

PURPOSE: To compare CT features of gastrointestinal stromal tumors (GIST) with those of lymphomas in the small intestine. MATERIALS AND METHODS: CT findings of 11 pathologically confirmed GIST patients and 10 lymphoma patients were retrospectively reviewed. CT findings were analyzed with regard to location, size, margin, growth patterns, internal character, enhancement, invasion, vascular encasement, lymphadenopathy, intestinal obstruction and ascites. RESULTS:An extraluminal mass was present in 82% (9/11) of the GIST patients versus 30% (3/10) of the lymphoma patients. Circumferential wall thickening was observed in 80% (8/10) of the lymphoma patients (p.05). CONCLUSION: Features revealed by CT scans are highly useful in differentiating GIST from lymphoma of the small intestine. Extraluminal growth and internal necrosis or gas are more common in patients with GIST compared with lymphoma. CT features of circumferential wall thickening and associated lymphadenopathy are more common in patients with lymphoma.

Treatment of Malignant Gastroduodenal Obstruction with Using a Newly Designed Complex Expandable Nitinol Stent: Initial Experiences

PURPOSE: We wanted to evaluate the usefulness of a new type of a complex expandable nitinol stent that was designed to reduce the stent's propensity to migration during the treatment of malignant gastroduodenal obstructions. MATERIALS AND METHODS: Two types of expandable nitinol stent were constructed by weaving a single thread of 0.2 mm nitinol wire in a tubular configuration: an uncovered stent 18mm in diameter and a covered stent 16mm in diameter. Both ends of the covered stent were fabricated by coaxially inserting the covered stent into the tubular uncovered stent and then attaching the two stents together with using nylon monofilament. Under fluoroscopic guidance, the stent was placed in 29 consecutive patients (20 men and 9 women, mean age: 65 years) who were suffering with malignant gastric outlet obstruction (n=20), duodenal obstruction (n=6) or combined obstruction (n=3). Clinical improvement was assessed by comparing the food intake capacity before and after the procedure. The complications were investigated during the follow up period. RESULTS: Stent placement was successful in all the patients. After stent placement, the symptoms improved in all but one patient. During the follow up, stent migration occurred in one patient (3%) at 34 days after the procedure. Despite the stent migration, the patient was able to resume a soft diet. Six patients developed recurrent symptoms of obstruction with tumor overgrowth at a mean of 145 days after the procedure; all the patients underwent coaxial placement of an additional stent with good results. One patient showed recurrence of obstruction due to tumor in-growth, and this was treated by placement of a second stent. Two patients with stent placement in the duodenum suffered from jaundice 26 days and 65 days, respectively, after their procedures. CONCLUSION: Placement of the newly designed complex expandable nitinol stent seems to be effective for the palliative treatment of malignant gastroduodenal obstructions. The new stent also seems to help overcome the disadvantage of the increased migration observed for the covered stent.