Chio Okuyama

Pitfalls of FDG-PET for the diagnosis of osteoblastic bone metastases in patients with breast cancer

PurposeThe purpose of this study was to investigate the pitfalls of using 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for the evaluation of osteoblastic bone metastases in patients with breast cancer by comparing it with 99mTc-hydroxymethylene diphosphonate bone scintigraphy.MethodsAmong the 89 breast cancer patients (mean age 59±15 years) who had undergone both FDG-PET and bone scintigraphy within 1 month between September 2003 and December 2004, 55 with bone metastases were studied. The bone metastases were visually classified by multi-slice CT into four types according to their degree of osteosclerosis and osteolysis—osteoblastic, osteolytic, mixed and invisible—and compared in terms of tracer uptake on FDG-PET or bone scintigraphy and SUVmean on FDG-PET. Differences in the rate of detection on bone scintigraphy and FDG-PET were analysed for significance by the McNemar test.ResultsThe sensitivity, specificity and accuracy of bone scintigraphy were 78.2%, 82.4% and 79.8% respectively, and those of FDG-PET were 80.0%, 88.2% and 83.1%, respectively, revealing no significant differences. According to the CT image type, the visualisation rate of bone scintigraphy/FDG-PET was 100%/55.6% for the blastic type, 70.0%/100.0% for the lytic type, 84.2%/94.7% for the mixed type and 25.0%/87.5% for the invisible type. The visualisation rates of bone scintigraphy for the blastic type and FDG-PET for the invisible type were significantly higher. The SUVmean of the blastic, lytic, mixed and invisible types were 1.72±0.28, 4.14±2.20, 2.97±1.98 and 2.25±0.80, respectively, showing that the SUVmean tended to be higher for the lytic type than for the blastic type.ConclusionFDG-PET showed a low visualisation rate in respect of osteoblastic bone metastases. Although FDG-PET is useful for detection of bone metastases from breast cancer, it is apparent that it suffers from some limitations in depicting metastases of the osteoblastic type.

Assessment of left ventricular diastolic function from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPET.

Abstract. We have developed new software which can evaluate left ventricular (LV) diastolic functional parameters from a quantitative gated SPET (QGS) program. To examine its accuracy, we compared these findings with the LV diastolic functional indices obtained from gated radionuclide ventriculography (RNV). Twenty-four patients were selected for this study. Gated SPET with technetium-99m tetrofosmin was performed and the QGS program was used with a temporal resolution of 32 frames per R-R interval. The LV volume of each frame was calculated and four harmonics of Fourier series were retained for the analysis of the LV volume curve. From this fitted curve and its first derivative curve, we derived LV systolic functional indices, e.g. ejection fraction (EF), peak ejection rate (PER) and time to PER (TPER), as well as LV diastolic functional variables, e.g. 1/3 filling fraction (1/3 FF), peak filling rate (PFR) and time to PFR (TPFR). Within 5±2 days, gated RNV was performed and diastolic functional parameters were determined by the same method. No significant difference was observed between the variables calculated by gated SPET and by gated RNV. There was a good correlation between EF, PER, TPER, 1/3 FF, PFR and TPFR determined by these two methods (EF: r=0.95, P<0.0001; PER: r=0.87, P<0.0001; TPER: r=0.84, P<0.0001; 1/3 FF: r=0.87, P<0.0001; PFR: r=0.92, P<0.0001; TPFR: r=0.89, P<0.0001). Bland-Altman plots did not reveal any significant degree of directional measurement bias in any of the comparisons of gated SPET data and RNV data. It is concluded that, in addition to the conventional LV systolic functional indices, our program accurately provides LV diastolic functional parameters from gated SPET. Also, this program will be useful for detecting LV diastolic dysfunction in various cardiac diseases before LV systolic dysfunction becomes evident.

Insular Hypoperfusion Correlates with the Severity of Delusions in Individuals with Alzheimer’s Disease

Background: The aim of this study was to identify the brain regions associated with the severity of delusions in individuals with Alzheimer’s disease (AD) using single-photon emission computed tomography. Methods: Thirty-five AD patients participated in this study. Multiple regression analysis was performed to identify a linear correlation between the delusion subscale score of the Neuropsychiatric Inventory (NPI) and regional cerebral blood flow (rCBF) in AD patients with delusions (n = 14). In addition, rCBF in patients with (n = 14) and without delusions (n = 21) was compared using a 2-sample t test. Results: The delusion subscale score of the NPI was negatively correlated with rCBF in the right anterior insula (uncorrected p < 0.01 at the voxel level and corrected p < 0.05 at the cluster level). Compared to patients without delusions, however, rCBF in the right anterior insula was not significantly decreased in patients with delusions. Conclusion: We suggest that right anterior insular dysfunction may exacerbate delusions, although it is not responsible for the onset of delusions.

Relationship between cognitive function and regional cerebral blood flow in Alzheimer's disease

The Mini-Mental State examination (MMSE) is frequently used to assess the cognitive function of neurological patients. The purpose of this study was to investigate associations between regional cerebral blood flow (rCBF) and MMSE scores in Alzheimers disease (AD) and localization of cognitive functions. Fifty-nine patients with probable AD (21 males and 38 females; mean age 74 years) and 12 normal volunteers (five males and seven females; mean age 73 years) were studied. CBF was measured by SPECT using the N-isopropyl-p-[123I]iodoamphetamine autoradiography method. The CBF images were reconstructed in parallel with the orbitomeatal line and parallel to the long axis of the temporal cortex. Regions of interest were set in the cerebral and cerebellar cortex. Multivariate analysis was performed by the step-wise method, using each section of the MMSE as the dependent variable and the rCBF ratio as the independent variable. The decline in rCBF in the parietal cortex and hippocampus reflected disorientation, and the most significant cortex affecting scores on each section of the MMSE were found to be the anterior temporal cortex for registration, the frontal cortex for attention and calculation, the medial temporal cortex for recall, and the posterior temporal cortex for language.

Reverse redistribution of Tc-99m-tetrofosmin in patients with acute myocardial infarction

We examined reverse redistribution (RR) of Tc-99m-tetrofosmin after a single injection in patients with acute myocardial infarction (AMI). Tc-99m-tetrofosmin myocardial SPECT was performed in 28 patients with AMI 10–14 days after the onset. Myocardial images were obtained 30 min and 180 min after the injection of 740 MBq of Tc-99m-tetrofosmin. The left ventricular wall was divided into 9 segments. Regional myocardial uptakes of Tc-99m-tetrofosmin were scored by 4-point scoring (0 = normal, 1 = mildly reduced, 2 = moderately reduced, and 3 = defect). RR was defined as an increase of more than 1 in the regional score in images at 180 min. RR of Tc-99m-tetrofosmin was observed in 17 of 20 patients with direct PTCA and 3 of 8 patients without reperfused therapy. RR was observed in 61 of all 252 segments. Coronary angiography performed 1 month later revealed that the infarct-related artery was patent in 19 of 20 patients (95%) with RR and in 3 of 8 patients (37.5%) with persistent defects (PD) (p < 0.05). In segment-by-segment analysis, the incidence of regional wall motion abnormality 1 month later was reduced in regions with RR compared to those with PD (p < 0.0001). In conclusion, RR of Tc-99m-tetrofosmin was frequently observed in patients with successful direct PTCA. As the segments with RR showed signs of preserved function 1 month later, this phenomenon may reflect a salvaged myocardium in AMI.

Simultaneous impairment of intracranial and peripheral artery vasoreactivity in CADASIL patients.

Background: Reduced cerebrovascular reactivity (CVR) is an important step in the pathogenesis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The present study utilized quantitative single photon emission computed tomography (SPECT) with the autoradiographic (ARG) method and reactive hyperemia peripheral arterial tonometry (RH-PAT) to assess vasoreactivity in intracranial arteries and in peripheral arteries in patients with CADASIL. Methods: Quantitative SPECT studies were conducted in eight patients with CADASIL, while RH-PAT analysis was conducted in eight CADASIL patients and in eight age-matched normal subjects. Quantitative SPECT studies with the ARG method were performed at baseline and after administration of acetazolamide. Regional cerebral blood flow (rCBF) values were measured using stereotactic extraction estimation (SEE) methods. The rCBF of CADASIL patients was averaged in the bilateral frontal, temporal, parietal, and occipital lobes as well as in the limbic system, cerebellar hemisphere, whole cerebral cortex and basal ganglia. The CVR index from acetazolamide stress of intracranial arteries was calculated in each area. Vasoreactivity of peripheral arteries was estimated by the reactive hyperemia index (RHI) measured with a PAT device before and after interruption of arterial flow. Results: Average RHI after post-deflation was lower in CADASIL patients than in normal subjects. RHI correlated significantly with CVR in all brain areas in CADASIL patients. Conclusions: Vasoreactivity is reduced in peripheral arteries and in intracranial arteries in patients with CADASIL.

Measurement of cerebral blood flow using graph plot analysis and I-123 iodoamphetamine.

Purpose N-isopropyl-p[I-123]iodoamphetamin (IMP) is transiently taken up by the lungs after intravenous injection and its concentration in arterial blood varies depending on the degree of I-123 IMP uptake and subsequent washout. A method that does not require arterial blood sampling would be valuable to measure cerebral blood flow (CBF) using I-123 IMP. Methods The authors developed a new theory and a convenient new method of CBF determination using I-123 IMP that does not require blood sampling. Dynamic images of the head and chest were acquired immediately after intravenous injection of I-123 IMP in a series of 42 consecutive patients with cerebrovascular disorders or other brain diseases (31 men, 11 women; mean age, 58 ± 11 years). Changes in the I-123 IMP counts of the regions of interest set in the head and pulmonary trunk were analyzed by the graph plot method, and the F values (CBF index slope) determined were compared with the mean CBF levels obtained by simultaneous autoradiography. Result The F values correlated well with the mean CBF obtained by autoradiography (r = 0.818, P < 0.001). Conclusions This innovative I-123 IMP graph plot analysis method using the time–activity curve of the head and pulmonary trunk alone is a noninvasive, convenient way to measure CBF. It is expected to become the most useful clinical technique for measuring CBF with I-123 IMP. This method can be used for patient follow-up and for comparing different patient groups evaluated in regional CBF studies.

Incremental prognostic value of myocardial perfusion single photon emission computed tomography for patients with diabetes and chronic kidney disease

PurposeThis study estimates whether myocardial perfusion single photon emission computed tomography (SPECT) can predict the prognostic risk of cardiac events among patients with diabetes and relatively mild chronic kidney disease (CKD). MethodsData from 2423 patients in the Japanese Assessment of Cardiac Events and Survival Study were examined. Patients were classified into group A (diabetes−, CKD−), B (diabetes−, CKD+), C (diabetes+, CKD−), and D (diabetes+, CKD+). After 3 years of follow-up, the incidence of cardiac events and the ability of myocardial perfusion SPECT to estimate prognosis were evaluated. ResultsA total of 119 (4.9%) events (28 cardiac deaths, 25 myocardial infarctions, and 66 severe heart failures) occurred. Each type of event occurred more frequently in CKD compared with non-CKD groups with both diabetic and nondiabetic populations. Risk was higher in patients with high summed stress scores. Risk gradually increased in nondiabetic groups according to the decrease in the estimated glomerular filtration rate and roughly consisted of two diabetic groups with a cutoff of eGFR equal to 50 ml/min. ConclusionA high incidence of cardiac events is associated with CKD in both nondiabetic and diabetic patients. Summed stress scores obtained by myocardial perfusion SPECT have a highly incremental value for predicting the cardiac prognosis of patients with diabetes and CKD. These scores are useful for the risk stratification of asymptomatic patients with relatively mild renal dysfunction requiring neither dialysis nor renal transplantation.

Utility of follow-up studies using meta-[123I]iodobenzylguanidine scintigraphy for detecting recurrent neuroblastoma

Neuroblastomas sometimes recur after the initial disappearance of the tumour. We evaluated the utility of meta-[123I]iodobenzylguanidine (123I-MIBG) scintigraphy for the detection of recurrent neuroblastomas by comparing with the measurement of biochemical markers and clinical findings. Forty patients who had received treatment for neuroblastomas were included in the study. After the disappearance of the initial tumours, periodic measurements of urinary vanillyl mandelic acid, homovanillic acid and serum neuron specific enolase values, and an 123I-MIBG scintigraphy were performed. Whenever an abnormal finding was observed, other appropriate examinations and/or follow-up examinations were performed to elucidate the true state of the patient. Eleven recurrent episodes in eight patients were observed. Most of them occurred in the bone marrow or bone. Corresponding symptoms were observed in only two episodes; the other episodes were asymptomatic, and discovered by the periodic examinations. 123I-MIBG scintigrams visualized the recurrent tumours in 10 (91%) episodes. Elevated tumour markers were observed in only three episodes. 123I-MIBG scintigrams visualized most of the recurrent tumours, unless they were accompanied by any symptoms or elevations in biochemical tumour markers. Periodic examinations with 123I-MIBG scintigraphy appears to be a useful technique for the detection of the recurrences.

A case of cap polyposis investigated by scintigraphy with human serum albumin labeled with Tc-99m DTPA

Cap polyposis is a rare intestinal disease that can be difficult to differentiate from inflammatory bowel disease. When cap polyposis is suspected, it is important to confirm protein loss. A 54-year-old woman who had been treated for ulcerative colitis for 7 years had severe hypoproteinemia. Scintigraphy with Tc-99m-labeled DTPA complexed with human serum albumin showed protein loss from the descending colon. Left hemicolectomy and sigmoid colectomy were performed. Cap polyposis was diagnosed on the basis of histologic findings from an operative specimen. The patients diarrhea resolved after surgery and her hypoproteinemia improved. Scintigraphy with this label gave information helpful in the diagnosis of cap polyposis.