[Comparison with bone scintigraphy and MDCT findings in patients with round focal accumulation on bone scintigraphy].

PURPOSE: This study aimed to compare with bone scintigraphy showed round focal accumulation and Multidetector Row CT (MDCT) findings. METHODS: We obtained 101 patients (mean age 69.2 years; 75 men, 26 women) and 186 diseases. They were examined both MDCT and bone scintigraphy within a month of each other. We classified into two groups (with metastasis and spondylosis) according to their MDCT findings. Bone scintigraphy was estimated on planar image, MDCT was evaluated in three directions with 1 x 1 x 1 mm thickness. RESULTS: We determined 20 metastases cases and 81 of spondylosis. We could not judge abnormal findings on MDCT in 4 patients (1 metastasis, 3 spondylosis); thus, detectability by MDCT was 93.5%. In the spondylosis group, the accumulation lesions were localized on the lower vertebral body in 76 patients (59%), with most showing as osteophytes. In the metastasis group, 11 patients showed more than 1 accumulations, 9 were osteoblastic changes and 10 were lytic. There was a tendency that patients who accumulated more than 1 vertebral bodies (64%) had osteoblastic and irregular distribution and those who accumulated just one body (78%) were lytic and their locations were focused on the lateral side. CONCLUSION: For evaluating bone scintigraphy, MDCT finding was helpful to increase the detectability in bone metastasis. Therefore, we should refer to MDCT finding positively in reading bone scintigraphy.

Is FDG-PET/CT useful for managing malignant pleural mesothelioma?

OBJECTIVE: Imaging techniques such as CT, MRI and PET/CT have essential pre- and post-treatment roles in detecting tumors and evaluating the extension of malignant pleural mesothelioma (MPM). We sough to evaluate the advantages and limitations on FDG-PET/CT findings. PATIENTS AND METHODS: We performed 13 FDG-PET/CT studies in 9 patients with MPM (8 males, 1 female, aged 51 to 84 years, 9 at the initial diagnosis, 4 follow up studies). We reviewed FDG-PET/CT findings of primary tumors, recurrent tumors, lymph nodes, metastasis. RESULTS: All primary and recurrent tumors were FDG positive. The uptake patterns at initial diagnosis were; diffuse+multi-nodular uptake pattern in 5, diffuse irregular thickened uptake pattern in 2, some focal thickened pattern in one, and a slight diffuse uptake pattern in one. Two of the 3 patients diagnosed as N0 by PET and operated on had negative lymph nodes confirmed pathologically. The other patient diagnosed as N0 by PET, who had one month of time lag between PET/CT examination and surgery, was confirmed as N2 by extrapleural pneumonectomy. In 3 patients, hilar or mediastinal lymph nodes were difficult to distinguish from irregular pleural thickening. One patient had a FDG positive lymph node in the ipsilateral supraclavicular region confirmed as metastasis (N3). One patient had a FDG positive lymph node in the para-aortic region. Lung metastasis was seen in one patient (M1). In another patient, two focal nodular uptakes in the colon were detected and confirmed as colon polyps (pathologically Group 3-4). At restaging, 3 of 4 patients showed diffuse+multi-nodular uptake and one patient showed multi-nodular uptake. CONCLUSIONS: The utility of FDG-PET/CT is limited for evaluation of primary tumor extension and nodal status. FDG-PET/CT is useful for detecting distant metastasis and for evaluating activity in supraclavicular or abdominal lymph nodes. It is also useful for identifying unsuspected diseases.

Clear-cell sarcoma of the small intestine detected by FDG-PET/CT during comprehensive examination of an inflammatory reaction.

Clear-cell sarcoma (CCS) is a rare, malignant, soft-tissue tumor, which involves the extremities, particularly the foot and foot joint tendons and aponeuroses. It is morphologically similar to but histochemically distinct from malignant melanoma. CCS arising in the gastrointestinal tract has rarely been reported. The prognosis of CCS is reportedly poor because of the high incidence of metastases at the time of initial diagnosis and the high frequency of recurrence. We report a case of early-stage CCS of the small intestine detected by (18)F-fluoro-2-deoxy D-glucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT) during the comprehensive examination of an inflammatory reaction. In this case, FDG-PET/CT clearly visualized the lesion, which was difficult to detect by contrast CT.

FDG-PET/CT findings of autoimmune pancreatitis associated with idiopathic retroperitoneal fibrosis.

We report the fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) findings of autoimmune pancreatitis (AIP) associated with idiopathic retroperitoneal fibrosis. A 69-year-old male patient was admitted to our hospital with obstructive jaundice. Six months prior to this admission, he was treated with steroid therapy for retroperitoneal fibrosis. Laboratory data showed that elevated T-bil, C-reactive protein, amylase and immunoglobulin 4, and antinuclear antibodies were positive. Clinical history, laboratory data, CT image, and magnetic resonance imaging led to a diagnosis of autoimmune pancreatitis. To investigate the inflammatory activity, FDG-PET/CT was undertaken. FDG-PET/CT demonstrated diffuse intense FDG uptake in the enlarged pancreas and diffuse mild uptake in the region of the abdominal aorta-bilateral iliac arteries. A dilated right renal pelvis and upper ureter, corresponding to hydronephrosis probably caused by retroperitoneal fibrosis, were shown. An FDG-PET/CT was useful to evaluate inflammatory activity and morphological imaging, and supported our diagnosis of AIP and retroperitoneal fibrosis.

FDG-PET/CT for cancer management.

FDG-PET/CT is increasingly being used for staging, restaging, and treatment monitoring for cancer patients. The introduction of a PET/CT system enables both morphological and metabolic imaging to be performed in a single session. Knowledge of the normal physiologic distribution of FDG and an understanding of the clinical indications and limitations of PET/CT enable accurate diagnosis and thus a better level of care for patients.

FDG-PET/CT for diagnosis and follow-up of vasculitis.

We report three cases of vasculitis evaluated by FDG-PET/CT. Vasculitis is defined as inflammatory changes and necrosis in the aterial wall. The patients presented with non-specific symptoms such as fever up or elevated inflammatory markers. FDG-PET/CT clearly demonstrated intense FDG uptake in vessel walls. A 72-year-old female patient with a one month history of pyrexia had abnormal laboratory data suggesting an inflammatory process. FDG-PET/CT was very useful for the diagnosis of vasculitis. Steroid therapy was introduced. Normalization of laboratory data and symptomatic improvement correlated with normalization of FDG uptake in the vessels.

The retention indices of 201Tl-SPECT in brain tumors.

OBJECTIVE: The aim of this study was to assess the utility of 201Tl SPECT in the differential diagnosis of intracranial tumors and to determine the relationship between 201Tl uptake and histological types. METHODS: Thirty-eight patients (19 males and 19 females) with thirty-eight brain tumors were evaluated with 201Tl-SPECT. The early and delayed 201Tl uptake ratio was calculated, and the retention index (RI) was applied as follows; RI = delayed uptake ratio/early uptake ratio. RESULTS: The RI of malignant tumors was higher (0.72 +/- 0.18) than that of benign tumors (0.50 +/- 0.16) and the difference was statistically significant (p = 0.00045). The difference between high-grade glioma (0.80 +/- 0.15) and metastatic tumors (0.64 +/- 0.19) was statistically significant (p = 0.039). CONCLUSION: 201Tl-SPECT may add useful biochemical information and could differentiate malignant brain tumors from benign lesions, but the RI of metastatic tumors varied depending on the organs with the primary lesion and histological types.