Rouh-Fang Yen

The role of FDG-PET, HMPAO-SPET and MRI in the detection of brain involvement in patients with systemic lupus erythematosus.

Abstract. Involvement of the brain is one of the most important complications of systemic lupus erythematosus (SLE); however, its diagnosis is difficult due to the lack of effective imaging methods. We combined three brain imaging modalities – positron emission tomography with fluorine-18 2-fluoro-2-deoxy-d-glucose (FDG-PET), single-photon emission computed tomography with technetium-99m hexamethylpropylene amine oxime (HMPAO-SPET) and magnetic resonance imaging (MRI) – in order to detect brain involvement in SLE. Thirty-seven SLE patients, aged 22–45 years, were divided into three groups. Group 1 (G1) consisted of ten patients with major neuropsychiatric manifestations; group 2 (G2) consisted of 15 patients with minor manifestations; and group 3 (G3) consisted of 12 patients without manifestations. FDG-PET findings were abnormal in 51% of patients: 90% of G1, 67% of G2 and 0% of G3 patients respectively. HMPAO-SPET findings were abnormal in 62% of patients: 100% of G1, 73% of G2 and 17% of G3 patients respectively. MRI findings were abnormal in 35% of patients: 70% of G1, 40% of G2 and 0% of G3 patients respectively. Grey matter was more commonly involved than white matter; 62% of patients presented with lesions in the cerebral cortex, 27% with lesions in the basal ganglion, 5% with lesions in the cerebellum, and 19% with lesions in white matter. No white matter lesions were found on FDG-PET or HMPAO-SPET. However, in 19% of patients, MRI demonstrated abnormally high signal lesions in white matter. Forty-three percent of cases had positive serum anticardiolipin antibodies (ACA). However, ACA was not related to FDG-PET, HMPAO-SPET or MRI findings. It may be concluding that HMPAO-SPET is a more sensitive tool for detecting brain involvement in SLE patients when compared with FDG-PET or MRI. However, MRI is necessary for detecting lesions in white matter.

Serial measurements of serum alkaline phosphatase for early prediction of osteopaenia in preterm infants.

Aim:  Osteopaenia commonly occurs in preterm infants; however, its diagnosis is often delayed when based on radiological findings. The aim of this study was to examine whether serial measurements of bone turnover markers are useful for early prediction of osteopaenia in preterm infants.

Usefulness of PET/CT for the differentiation and characterization of periampullary lesions.

Purpose At present, there is no ideal imaging modality for the diagnosis of periampullary lesions. We prospectively evaluated the preoperative diagnostic usefulness of PET/CT for differentiating malignant from benign periampullary lesions. Methods A total of 62 patients aged 27–86 years with periampullary lesions scheduled for surgical resection were consecutively recruited. Dual-phase 18F-FDG PET/CT was performed in all patients. An additional 3′-deoxy-3′-[18F]fluorothymidine (FLT) scan was performed in 21 patients (33.9%). The relationship of visual interpretation, SUV, and lesion to background ratio (LBR) with surgical histopathology diagnosis was evaluated. Results There were 36 patients with malignancies, 15 with benign neoplasms, and 11 with benign non-neoplasms. Using visual analysis, FDG PET/CT had good sensitivity (86.1%; 31/36), lower specificity (57.7%; 15/26), and fair accuracy (74.2%; 46/62). Regional lymph node metastases were identified in 7 of 11 patients by FDG PET/CT and only in 1 patient by abdominal CT. On the other hand, hepatic metastasis was detected in 1 patient by FDG PET/CT. Dual-phase FDG (P < 0.001) and FLT (P < 0.05) SUVmax and LBR were significantly higher in malignant than in benign lesions, and in malignant neoplasms than in benign neoplasms. Although average FLT SUVmax was significantly lower than the average FDG SUVmax (P < 0.001), the specificity and accuracy of the former were significantly better. Conclusion FDG PET/CT may help identify patients with periampullary malignancy. FDG SUVmax and LBR appear to aid in the differential diagnosis and add diagnostic confidence. In addition, higher specificity and diagnostic accuracy may be achieved by additional FLT PET/CT.

Left ventricle metastasis of esophageal cancer mimicking myocardial infarction in myocardial perfusion scintigraphy.

a Department of Nuclear Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan b Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan c Department of Nuclear Medicine and Cardiology Division of Cardiovascular Medical Center, Far Eastern Memorial Hospital, New Taipei City, Taiwan d National Yang-Ming University School of Medicine, Taipei, Taiwan

Postoperative lymphocele demonstrated by lymphoscintigraphy SPECT/CT.

Lymphoscintigraphy is a useful and safe tool for the diagnostic evaluation of a swollen extremity as well as sentinel lymph node biopsy in malignancies. Here, we report a 34-year-old woman who developed progressive abdominal distention and bilateral lower limb edema 3 months after simultaneous pancreas and renal transplantation. Color Doppler-duplex ultrasound revealed patent deep veins of bilateral lower extremities without evidence of thrombosis. Lymphoscintigraphy demonstrated a large area of tracer accumulation at left lower quadrant of abdomen, suggestive of a postoperative lymphocele. SPECT/CT successfully localized the lesion near the renal graft.

PET/MRI for evaluating subclinical inflammation of ulcerative colitis

To explore the utility of integrated positron emission tomography (PET) / magnetic resonance imaging (MRI) for evaluating subclinical inflammation in patients with ulcerative colitis (UC).

Search of Unknown Fever Focus Using PET in Critically Ill Children With Complicated Underlying Diseases.

Objectives: PET/CT with 18F-fluorodeoxyglucose can be used to image cellular metabolism and has been used for evaluating fever of unknown origin in adults. However, there are limited studies about the role of 18F-fluorodeoxyglucose PET/CT in evaluation of fever of unknown origin in critically ill children, especially those presenting with complicated underlying diseases under treatment. Here, we report our preliminary experience using 18F-fluorodeoxyglucose PET/CT in this specific group of patients. Design: Retrospective observational study. Setting: PICUs of a university hospital. Patients: Nineteen critically ill children (mean age, 5.7 yr old) with complicated underlying diseases requiring intensive care support underwent 18F-fluorodeoxyglucose PET/CT to evaluate fever of unknown origin. The median hospitalized stay was 34 days (range, 15–235 d) and fever of at least 7 days (mean, 21.6 d; range, 7–52 d). The PET scan was advocated after all routine microbiology, and conventional imaging showed negative or inconclusive results. Interventions: None. Measurements and Main Results: The 18F-fluorodeoxyglucose PET/CT findings (blinded to the final clinical diagnosis) were compared with final histopathology, culture, serology results, or follow-up imaging. A final diagnosis was made in 16 patients (84.2%). 18F-fluorodeoxyglucose PET/CT accurately localized the source of fever in 14 patients, confers to a sensitivity of 87.5% (14 of 16; 95% CI, 0.604–0.978). A false-positive scan in a patient led to subsequent unnecessary investigations. Two false-negative 18F-fluorodeoxyglucose PET/CT images were later attributed to relapse of underlying disease in the bone marrow and renal abscesses, respectively. In the other two patients where 18F-fluorodeoxyglucose PET/CT also showed negative findings, fever subsided shortly thereafter without treatment. Conclusions: Our preliminary experience suggests that 18F-fluorodeoxyglucose PET/CT may be clinically beneficial in evaluating fever of unknown origin in children with complicated underlying diseases mandating intensive support in ICUs if usual investigative methods are unsuccessful. Further large prospective studies are needed to validate these findings.

Atypical thymic carcinoid associated with coronary artery spasm: Incidental finding of myocardial perfusion imaging

a Department of Nuclear Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan b Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan c Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan d Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan e Division of Nuclear Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan