Clinical implications of 18F-fluorodeoxyglucose positron emission tomography/computed tomography at delayed phase for diagnosis and prognosis of malignant pleural mesothelioma.

Malignant pleural mesothelioma (MPM) has a poor prognosis, and conventional imaging modalities do not reflect the prognosis of MPM. In this study, the clinical significance of 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) was evaluated for the differential diagnosis, staging and prognosis in MPM patients. Ninety patients who underwent 18F-FDG PET/CT scanning due to a clinical diagnosis or suspicion of MPM prior to therapy were reviewed. Of 90 patients, 31 were pathologically diagnosed as MPM. Maximum standardized uptake values (SUVmax) were semi-quantitatively obtained from PET/CT 60 min (early phase) and 120 min (delayed phase) after injection of 18F-FDG, and the clinicopathological correlations with the level of SUVmax obtained from PET/CT were examined. The survival curves of MPM patients were plotted according to the methods of Kaplan-Meier. The prognostic implications of the level of SUVmax were estimated by t-test. PET/CT scan showed intense abnormal FDG uptake (SUVmax>2.0) in the pleural lesions of all 31 MPM patients at delayed phase, while it showed abnormal FDG uptake in 30 (97%) patients at early phase. In all 31 MPM patients, the values of SUVmax at delayed phase were higher than those at the early phase. PET/CT also indicated metastasis in the lymph node in 7 patients (23%) and in the systemic lesions in 8 patients (26%) with MPM. Twenty-three MPM patients with high SUVmax, whose prognosis was apparent, showed significantly poorer prognosis in both early and delayed phase (respectively, p=0.03 and p=0.01, t-test). The results showed that 18F-FDG PET/CT at delayed phase is very useful for the diagnosis of pleural diseases, and SUVmax on PET/CT in the delayed phase is a more reliable prognostic factor than that in the early phase. High uptake of 18F-FDG PET/CT may be a predictive factor of prognosis in MPM patients.

A case of primary lung cancer lesion demonstrated by F-18 FDG positron emission tomography/computed tomography (PET/CT) one year after the detection of metastatic brain tumor.

Cancer of unknown primary origin (CUP) is an aggressive disease with a poor prognosis. Metastatic brain tumors occur in approximately 15% of all cancer patients. F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography (PET) combined with computed tomography (PET/CT) contributes to the evaluation of cancer staging, although the benefits of PET/CT for detection of CUP origins has yet to be determined. In this study, we present a 37-year-old man with a brain tumor detected by magnetic resonance imaging. Surgical biopsy indicated a metastatic undifferentiated carcinoma, while clinical examination and a CT scan did not detect any abnormalities, with the exception of brain metastases. PET/CT did not reveal abnormal FDG uptake. PET/CT revealed abnormal intense FDG uptake in a small nodular lesion in the right lung 1 year following the detection of brain metastasis, and no other abnormal FDG uptake was observed elsewhere in the body. Right upper lobectomy and dissection of mediastinal lymph nodes were performed. The pathological diagnosis was poorly differentiated adenocarcinoma, which was similar to the brain metastatic lesion, and there was no lymph node metastasis. This case revealed an extremely rare lung cancer with primary lesions demonstrated by PET/CT 1 year after the detection of brain metastasis. This case reveals that F-18 FDG PET/CT imaging of CUP origin is capable of positively impacting on the identification of small primary tumor foci.

Unique intense uptake demonstrated by (18)F-FDG positron emission tomography/computed tomography in primary pancreatic lymphoma: A case report.

Patients with primary pancreatic lymphoma (PPL), which is rare, require a different therapeutic approach and have a better prognosis than those with pancreatic cancer. However, conventional imaging modalities alone are not able to differentiate between pancreatic cancer and other rare tumors such as PPL, although the accurate diagnosis of PPL is crucial. The development of new modalities such as F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with computed tomography (PET/CT) contributes to the evaluation of lymphoma staging. However, few reports are currently available regarding PET/CT findings in PPL. In this study, a 56-year old man with PPL was examined using FDG PET/CT imaging, which showed the unique intense uptake of FDG in the pancreas with atypical findings of malignancy in the CT scan and magnetic resonance images.

Usefulness of (18)F-FDG positron emission tomography/computed tomography for the diagnosis of pyothorax-associated lymphoma: A report of three cases.

Pyothorax-associated lymphoma (PAL) is a unique and rare non-Hodgkin's lymphoma developing in the pleural cavity following a long-standing history of chronic pyothorax (CP). The development of F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with computed tomography (PET/CT) has contributed to the evaluation of lymphoma staging. However, only a few studies describing FDG-PET/CT findings in PAL have been published. This study reported three cases of PAL; all 3 patients had previously undergone artificial collapse therapy for pulmonary tuberculosis. Both the first case (an 84-year-old male) and second case (an 83-year-old male) complained of abdominal pain. An ultrasound scan revealed a mass shadow in the left chest wall without abnormal findings in the abdomen, and the CT and magnetic resonance imaging scans suggested malignant lymphoma of the left chest. FDG-PET/CT imaging showed extremely intense FDG uptake only in the left pleura and chest wall. Diagnosis was CP in the two patients, showing a high maximum standardized uptake value (SUVmax: early, 14.8 and delayed, 19.4 in the first case; early, 20.8 and delayed, 27.3 in the second case, respectively). Histopathological analysis of the specimens obtained by biopsy of the PET/CT-positive pleural mass showed non-Hodgkin's, diffuse large B cell lymphoma in the two cases. The third case was a 79-year-old male with relapse after right pleuropneumonectomy for PAL (diffuse large B cell lymphoma) 4 years earlier. PET/CT showed intense FDG uptake (SUVmax: early, 19.9 and delayed, 35.7) in the right pleura and chest wall. Diagnosis was CP, suggesting the recurrence of PAL. Furthermore, abnormal intense FDG uptake was noted in the hilar, mediastinal and supraclavicular lymph nodes, as well as in the spleen. In conclusion, FDG-PET/CT imaging is useful in the evaluation of the area of invasion in PAL.

Extraosseous accumulation of 99mTc-MDP in lymph node metastases of small cell carcinoma of the esophagus.

We report a case of esophageal carcinoma that showed extraosseous accumulation of 99mTc-MDP in lymph node metastases to the cervical and paracardial lymph nodes. There are few cases showing abnormal extraosseous accumulation of 99mTc-MDP in esophageal cancer lesion. The patient was a 53-year-old man with advanced esophageal cancer. Bone scintigraphy demonstrated extraosseous accumulations in left supraclavicular and paracardial lymph node metastases. The histopathological diagnosis was small cell carcinoma of the esophagus, which is a rare disease with aggressive behavior and poor prognosis. Our patient underwent 2 courses of systemic chemotherapy (CDDP + VP16), but died of rapidly growing systemic metastases 5 months after the initial treatment.

Adult embryonal rhabdomyosarcoma in axilla.

A case of embryonal rhabdomyosarcoma (RMS) arising from an axillary space is described. RMS is one of the most common soft-tissue neoplasms in children, but adult embryonal RMS is rare. The patient was a 55-year-old man with a tumor of the left axillary area. RMS arising from an axillary area is also uncommon. The histological diagnosis was embryonal RMS. He received irradiation combined with chemotherapy (VAC: VCR, act-D, CPA) for the primary and metastatic lesions, obtained complete remission, and has remained disease-free for over four years as of this report.

Gallium-67 demonstration of extensive soft-tissue involvement of multiple myeloma.

A 46-year-old woman with multiple myeloma presented with neurological symptoms in the right upper extremity. After MR imaging of the cervical spine failed to show the cause of her symptoms, Ga-67 scintigraphy demonstrated increased uptake in multiple areas including the right supraclavicular region and bilateral lower extremities. Histology of the specimen obtained from the left thigh proved soft-tissue involvement of myeloma, and extensive extramedullary involvement was diagnosed. Radiotherapy to the right supraclavicular mass relieved her symptoms. Although Ga-67 scintigraphy is generally considered of limited value in multiple myeloma, this modality contributed to the development of an appropriate strategy in this patient with extensive extramedullary involvement.

Intense Ga-67 accumulation in pure primary mediastinal seminomas.

The authors examined three patients with pure primary mediastinal seminomas, all of whom had marked Ga-67 uptake on scintigraphy. The unusual presentation of sclerotic bone metastases with remarkable extraosseous soft tissue involvement was observed in one patient. Another had a seminoma associated with a multiloculated thymic cyst, which is a rare lesion.

Three-dimensional stereotactic surface projection of brain perfusion SPECT improves diagnosis of Alzheimer's disease.

OBJECTIVES: Alzheimer's disease (AD) is diagnosed by either inspection of the brain perfusion SPECT, or three-dimensional stereotactic surface display (3D-SSP). The purpose was to compare diagnostic performances of these methods. METHODS: Sixteen nuclear medicine physicians independently interpreted 99mTc-ECD SPECT in one session and SPECT with 3D-SSP in another session without clinical information for 50 studies of AD patients and 40 studies of healthy volunteers. Probabilities of AD were reported according to a subjective scale from 0% (normal) to 100% (definite AD). Receiver operating characteristics curves were generated to calculate areas under the ROC curves (Az's) for the inspection as well as for an automated diagnosis based on a mean Z value in the bilateral posterior cingulate gyri in a 3D-SSP template. RESULTS: Mean Az for visual interpretation of SPECT alone (0.679 +/- 0.058) was significantly smaller than that for visual interpretation of both SPECT and 3D-SSP (0.778 +/- 0.060). Az for the automated diagnosis (0.883 +/- 0.037) was significantly greater than that for both modes of visual interpretation. CONCLUSIONS: 3D-SSP enhanced performance of the nuclear medicine physicians inspecting SPECT. Performance of the automated diagnosis exceeded that of the physicians inspecting SPECT with and without 3D-SSP.

Quantification of regional pulmonary flow with 9mTc-MAA SPECT and cine phase contrast MR imaging.

The purpose of this study was to evaluate the relationship between left and right pulmonary arterial flow measured by cine phase contrast magnetic resonance imaging (cine PCMRI) and the distribution of perfusion on 99mTc-MAA SPECT and to determine whether the regional pulmonary flow quantification was feasible with the combined use of these techniques. Twenty patients with different pulmonary diseases were evaluated. Left and right lung counts on 99mTc-MAA SPECT images were separately summed and the left-to-total count ratio was calculated. The left-to-total pulmonary flow ratio was calculated from the left and right main pulmonary flows measured with cine PCMRI. We evaluated the correlation and agreement between the ratio determined with 99mTc-MAA SPECT and cine PCMRI by linear regression analysis and Bland-Altman analysis. The left-to-total ratios obtained by 99mTc-MAA and cine PCMRI were 52.0 +/- 22.1% and 52.2 +/- 20.8%, respectively, and showed a strong correlation (r = 0.99, p < 0.001). The mean difference between the two methods in the ratio was 0.25 +/- 2.3% with a 95% confidence interval from -0.84 to 1.34. The results showed that the regional pulmonary flow was calculated with both the left and right pulmonary flow measured with cine PCMRI and the ratio of regional distribution on 99Tc-MAA SPECT images.

Scintigraphic findings of MALT lymphoma of the thyroid.

Mucosa-associated lymphoid tissue (MALT) lymphoma has been established as a distinct entity among non-Hodgkin's lymphomas, and the most common primary site is the stomach. We describe scintigraphic findings in a patient with MALT lymphoma of the thyroid. A 71-year-old woman with Hashimoto's thyroiditis suffered from rapid cervical swelling, and ultrasonography and CT revealed a thyroid nodule. The nodule showed accumulation of 99mTc pertechnetate comparable to the surrounding thyroid tissue, mimicking a benign nodule. Both 67Ga and 201Tl imaging visualized the lesion as an increased uptake area. After radiotherapy, abnormally increased uptake disappeared on 67Ga images, which predicted a favorable outcome. MALT lymphoma of the thyroid may be visualized as a warm nodule on 99mTc pertechnetate scintigraphy.

Interobserver variation in diagnosis of dementia by brain perfusion SPECT.

Brain perfusion SPECT (BP-SPECT) has characteristic patterns of abnormality, enabling the differential diagnosis of dementia. The purpose of this study was to measure interobserver variations in the diagnosis of dementia using BP-SPECT. BP-SPECT images of 57 cases, 19 of Alzheimer's disease (AD), eight of multi-infarct dementia (MID), three of Pick's disease, five of other dementias, and 22 normal controls, were interpreted by ten nuclear medicine physicians with varying levels of experience. Brain MR images of the cases were then interpreted apart from SPECT. The physicians independently rated all of the diagnoses listed beforehand according to a five-point scale, with clinical information provided. Receiver-operating characteristic (ROC) curves and the area under the ROC curve (Az) were calculated. Az varied from 0.48 to 0.87. Mean Az's were significantly larger (p<0.05) in the diagnosis by SPECT than in that by MRI (0.715 and 0.629 for dementia vs. normal, 0.670 and 0.560 for AD or MID vs. normal, 0.610 and 0.416 for AD vs. normal, and 0.672 and 0.412 for AD vs. MID, respectively). Considerable interobserver variation was present in BP-SPECT interpretation. BP-SPECT may be more effective for the evaluation of dementia than MRI when the same nuclear medicine physicians interpret both images.

Quantitative lung perfusion scintigraphy and detection of intrapulmonary shunt in liver cirrhosis.

OBJECTIVE: Frequent association between liver cirrhosis and hypoxemia has been well documented. It is mostly attributable to intrapulmonary shunt due to dilation of pulmonary vasculature. We performed quantitative lung perfusion scintigraphy to detect an intrapulmonary shunt in cirrhosis patients. METHODS: Prior to injection, Tc-99m MAA was applied to thin layer chromatography for quality control. Three cirrhosis patients who had hypoxemia were examined as well as 11 control subjects. After i.v. injection of Tc-99m MAA, whole body anterior and posterior images were taken at 5 min in patients with cirrhosis and at 8 time points up to 60 min in control subjects. Regions of interest were placed at the bilateral lungs and the whole body, and pulmonary accumulation was calculated. RESULTS: All the control subjects demonstrated more than 90% of radioactivity in the lungs until 20 min. In contrast, all the patients showed values less than 80% at 5 min. In the cirrhosis patients with hypoxemia, the presence of intrapulmonary shunt was confirmed on quantitative lung perfusion scan. In control subjects, pulmonary accumulation of Tc-99m MAA dropped as a function of time and became less than 90% after 30 min. CONCLUSION: The timing of measurements is essential in evaluating intrapulmonary shunt.