The effects of olanzapine treatment on brain regional glucose metabolism in neuroleptic-naive first-episode schizophrenic patients.

OBJECTIVE: The current study examined metabolic alterations associated with a positive response to olanzapine and identified brain regions associated with treatment-related improvement of symptoms in neuroleptic-naive first-episode schizophrenic patients using [18 F]fluoro-deoxy-glucose positron emission tomography analysis. METHODS: Neuroleptic-naive first-episode schizophrenic patients who showed good or poor clinical responses to olanzapine were assessed using the Positive and Negative Syndrome Scale. Data were analyzed using statistical nonparametric mapping. RESULTS: Before treatment, responders showed significantly increased metabolism in the superior temporal gyrus and cerebellum compared with healthy controls. Glucose metabolism in responders was significantly increased after treatment in the left precentral gyrus, left postcentral gyrus, and left paracentral lobule, and significantly decreased in the left hypothalamus. An analysis of the Positive and Negative Syndrome Scale symptoms associated with olanzapine treatment revealed that "suspiciousness/persecution" scores were positively correlated with metabolic changes in the right superior frontal gyrus. CONCLUSIONS: These findings provide evidence of the neural mechanisms underlying the effects of olanzapine on metabolism in the early stages of schizophrenia.

Different clinical phenotypes in siblings with a presenilin-1 P264L mutation.

BACKGROUND: Mutations in the presenilin-1 gene (PSEN1) have been identified in autosomal dominant early-onset cases of Alzheimer's disease (AD). AIMS: To investigate different clinical phenotypes of siblings possessing the same heterozygous P264L mutation in the PSEN1 gene. METHODS: We evaluated clinical features, neuroimaging results, and neuropsychological examinations. The PSEN1 gene and other dementia-related gene mutations were screened. RESULTS: We clinically diagnosed the proband as atypical AD with frontotemporal dementia features and diagnosed the elder brother of the proband as typical AD, based on neuropsychological symptoms and a brain imaging examination including amyloid imaging data. A heterozygous P264L mutation in the PSEN1 gene was identified in both siblings. CONCLUSION: This study is one of few reports of AD siblings possessing the same mutation but exhibiting different clinical phenotypes in a Japanese family possessing a P264L mutation in the PSEN1 gene. The current results suggest that unknown modifiers, including both genetic and epigenetic factors, may alter the pathological and clinical phenotypes of a genetically predetermined disease.

[Usefulness of metabolic volume and total lesion glycolysis for predicting therapeutic response in cancer therapy by 18F-FDG PET/CT].

PURPOSE: The current study was done to evaluate the usefulness of predicting capability of FDG PET/CT indices in therapeutic response of malignant tumor. METHODS: Series of FDG PET/CT were performed at both pre- and after therapy for 70 lesions of 58 patients with malignant tumor. Three months after the 2nd PET/CT, follow up CT was performed for determining the final therapeutic effect. We calculated various indices including SUVmax, the metabolic volume (MV) and the total lesion glycolysis (TLG). We calculated four kinds of indices, TLG50, TLG75, MV50 and MV75 based on the different threshold. Then we calculated deltaSUVmax, deltaMV50, deltaMV75, deltaTLG50 and deltaTLG75 from a change of these indices. Finally, we compared the predictive capability of these five indices in therapeutic response of malignant tumor. RESULTS: In the cancer therapy effect prediction, both deltaTLG75 and deltaTLG50 were significantly higher than SUVmax by using receiver operating-characteristic (ROC) curve analysis. The prognostic capability of deltaSUVmax for therapeutic response with sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.7%, 59.5%, 58.5%, 86.2% and 70.0%; deltaTLG75 96.4%, 69.0%, 67.5%, 96.7% and 80.0%; and deltaTLG50 96.4%, 76.2%, 73.0%, 97.0% and 84.3%, respectively. By the use of deltaTLG75 or deltaTLG50, the predictive ability for therapeutic response improved significantly compared to that by the use of deltaSUVmax. CONCLUSION: In the prediction for therapeutic response of various cancers by using FDG PET/CT, Total lesion glycolysis (TLG) was the most useful index.

Usefulness of a deep-inspiration breath-hold 18F-FDG PET/CT technique in diagnosing liver, bile duct, and pancreas tumors.

BACKGROUND: The deep-inspiration breath-hold F-fluorodeoxyglucose PET/computed tomography (DIBH F-FDG PET/CT) technique improves the limitations of diagnosing a lesion located in an area influenced by respiratory motion that brings about spatial misregistration caused by respiration between PET and CT. However, its clinical effectiveness with regard to abdominal lesions has not been elucidated. The influence of respiratory motion for calculating the maximal standardized uptake value (SUVmax) and metabolic volume (MV) in DIBH F-FDG PET/CT has not been investigated either. OBJECTIVE: The purpose of this study was to investigate the usefulness of the DIBH F-FDG PET/CT technique in diagnosing liver tumors, bile duct cancers, and pancreas tumors. In addition, we compared the values of SUVmax and MV between DIBH and nonbreath-hold (NBH). METHODS: Forty patients with various abdominal malignancies including liver tumors, bile duct cancers, and pancreas tumors were enrolled. In total, the patients had 47 abdominal lesions. All patients showed a misregistered image in the early whole-body image taken 50 min after intravenous F-FDG infusions. We added the delayed images 40 min after the first image. On the delayed image, we carried out both conventional techniques with normal respiration (NBH) and the DIBH technique. Finally, we compared two kinds of images in each patient. At the same time, we compared both SUVmax and MV of cancer obtained by the two kinds of imaging methods. RESULTS: In 14 lesions (29.8%), we corrected the anatomical tumor location, from the incorrect to the correct organ, by the DIBH technique. In 22 lesions (46.8%), we corrected the tumor location within the organ. Consequently, tumor staging also changed in 11 patients (23.4%) after correction by the DIBH technique. Regarding the SUVmax value by DIBH, it showed an increase of approximately 15.0-58.6% compared with that measured by NBH. In contrast, the value of MV by DIBH showed a decrease of 20% compared with that measured by NBH. CONCLUSION: The DIBH F-FDG PET/CT technique is feasible for accurate localization when diagnosing of liver tumors, bile duct cancers, and pancreas cancers. The DIBH technique also improves the inaccurate quantification of both SUVmax and MV.

Metabolic changes in the brain of patients with late-onset major depression.

Positron emission tomography (PET) with fluorodeoxyglucose-F18 was used to examine glucose metabolism in patients with late-onset major depression, all hospitalized non-responders to antidepressant medication. The three-dimensional stereotactic surface projection (3D-SSP) method provided 3D-SSP images and relative metabolic values with minimal partial volume effects. The 3D-SSP score map showed decreased relative metabolism in the prefontal, cingulate and parietal regions in both hemispheres, and in the temporal region on the right, and increased relative metabolism in the occipital pole, vermis, cerebellum, dorsal-frontal, central convexity areas and basal ganglia in both hemispheres in patients compared with controls. The ratio of the parietal to occipital values in right plus left hemispheres was significantly decreased. Correlation coefficients of the anterior cingulate-primary sensorimotor, posterior cingulate-primary sensorimotor and occipital-media frontal in both hemispheres, of the frontal-primary sensorimotor, occipital-parahippocampal, primary visual-medial frontal and parahippocampal-amygdala in the right, and the frontal-vermis, parietal-thalamus, temporal-vermis, occipital-putamen, primary visual-putamen, thalamus-vermis and thalamus-cerebellum in the left were significantly different in patients compared with controls. Patients with late-onset depression who were treatment non-responders showed alterations not only in limbic-cortical circuits, but also in a wider network of thalamo-cortical circuits.

Changes in glucose metabolism due to aging and gender-related differences in the healthy human brain.

Using [(18)F]fluoro-deoxy-glucose-PET, we studied relative metabolic changes due to age- and gender-related differences in the brain of 126 healthy subjects from their twenties to seventies. We used a data-extraction technique, the three-dimensional stereotactic surface projections (3D-SSP) method, to measure metabolic changes with fewer effects of regional anatomic variances. Simple regression analysis revealed significant age-related increases in relative metabolic values in the parahippocampal and amygdala regions in both sexes in their twenties to forties, and significant age-related decreases in both sexes in their fifties to seventies. Relative values in the frontal lobe showed significant age-related decreases in both sexes in their twenties to forties, but these effects were not seen in subjects in their fifties to seventies. Significant gender differences in correlation coefficients of relative values with age were shown in the parahippocampal, primary sensorimotor, temporal, thalamus and vermis regions in subjects in their 20s to 40s, but disappeared in subjects in their twenties to forties, but were not apparent in subjects in their fifties to seventies except in the vermis. Males in their twenties to sixties and females in their fifties showed significant laterality in relative values in the temporal lobes. Our study demonstrated age- and gender-related differences in glucose metabolism in healthy subjects.

Effect of percutaneous endoscopic gastrostomy on gastrointestinal motility: evaluation by gastric-emptying scintigraphy.

PURPOSE: Firstly, to assess the effect of percutaneous endoscopic gastrostomy (PEG) tube placement on gastric emptying, gastrointestinal (GI) tract motility and the rate of gastroesophageal reflux (GER). Secondly, to confirm whether correlations exist between drug absorption behaviour and GI tract motility using the combination method of absorption function analysis with the motility study. METHODS: Subjects comprised 11 patients with neurological dysphagia. Gastric-emptying scintigraphy was performed both before PEG via nasogastric tube feeding and after PEG placement. After fasting for more than 8 h, each patient was administered 111 MBq of 99mTc-labelled diethylenetriaminepentaacetic acid (DTPA) with a 100 ml liquid meal via a nutrition tube. Dynamic imaging was performed immediately after administration of a radiolabelled liquid meal for a 1 h period and static imaging was performed after 1, 2, 3 and 6 h. Gastric emptying half-time (T50) was calculated in each patient, and GER ratio and GI transit rate were also evaluated. Simultaneously, we administered 10 mg of famotidine in six of the 11 patients and measured serum concentrations of famotidine at 0, 1, 2, 3 and 6 h. Using the time-concentration curve of famotidine, the maximum concentration of famotidine (Cmax) and area under the curve of famotidine (AUCf) were calculated for each patient. RESULTS: In seven of 11 patients, T50 changed after PEG placement, but not significantly. The GER ratio was significantly decreased and complicated pneumonia improved after PEG placement. GI transit rate for each GI segment was unchanged after PEG placement. Significant linear correlations were identified between T50 and both Cmax and AUCf. CONCLUSION: Gastric-emptying scintigraphy with Tc-DTPA was effective in the evaluation of GI transit before and after PEG, as well as in assessing GER. Motility and famotidine absorption were maintained after PEG placement. Significant linear correlations were found between T50 and both Cmax and AUCf. These findings suggest that drug absorption may have some relationship between T50. The result may be more reliable with a larger population.

Usefulness of triple-phase thallium-201 SPECT in non-small-cell lung cancer (NSCLC): association with proliferative activity.

OBJECTIVE: The conventional delayed scan in dual phase of thallium-201 ((201)Tl) single-photon emission computed tomography (SPECT) is useful for estimating the viability of non-small-cell lung cancer (NSCLC). However, the influence of tumor blood flow cannot be ignored by the scan at 4 h after the tracer injection. For the purpose of improving the diagnostic capability and for clarifying the association between (201)Tl uptake and proliferative activity, we investigated the usefulness of super-delayed scan obtained at 24 h in triple-phase (201)Tl SPECT. METHODS: A total of 122 patients with lung nodule, 106 of NSCLC and 16 of benign nodule, were given (201)Tl SPECT before the tumor resection. Early image (15 min), delayed image (4 h), and super-delayed image (24 h) were obtained after intravenous injection of (201)Tl chloride (111 MBq). On the each SPECT image, regions of interest (ROIs) were placed over the tumor contour (T) and contra-lateral normal lung tissue (N) area on one transverse view clearly defined lesions, and T/N ratio on the early image (ER), the delayed image (DR), and the super-delayed image (sDR), and retention indexes (RI and sRI) were calculated. All patients underwent subsequent surgical excision, and the specimens were immunostained for Ki-67 and CD34. The proliferative capability was measured as a percentage of positive nuclear area for Ki-67 (MIB-1 index). The angiogenesis was measured density of positive micro-vessels for CD34 (micro-vessel density, MVD). Correlation analysis was performed to evaluate the relationship between the MIB-1 index, MVD, and SPECT parameters. RESULTS: The diagnostic accuracy of sDR in the differential of NSCLC was higher than that of DR (83.6% vs. 91.8%). Both DR and sDR were positively correlated with MIB-1 index. The correlation coefficient was higher in sDR (0.53 vs. 0.69). The MIB-1 index of the increasing pattern (RI < sRI) group was significantly higher (P < 0.001) than that of the decreasing pattern (RI > sRI) group. CONCLUSIONS: The super-delayed scan in the triple-phase (201)Tl SPECT is more useful than conventional delayed scan for both the diagnostic capability and assessing proliferation of NSCLC.

Usefulness of rCBF analysis in diagnosing Parkinson's disease: supplemental role with MIBG myocardial scintigraphy.

UNLABELLED: (123)I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy is a useful tool for differentiating idiopathic Parkinson's disease (PD) from parkinsonism (PS) caused by other disorders. However, cardiac MIBG uptake is affected by various causes. Alternatively, hypoperfusion in the occipital lobe of PD is reported recently. OBJECTIVE: The objective is to clarify the correlation between regional cerebral blood flow (rCBF) alteration and cardiac MIBG uptake in PD. In addition, we examined whether additional brain perfusion analysis improved the differential diagnostic ability for PD from PS when compared with MIBG scintigraphy alone. METHODS: Forty-nine patients with PD (27 mild groups: Hoehn and Yahr stages I, II; 22 severe groups: Hoehn and Yahr stages III, IV) and 28 patients with PS participated. We compared absolute rCBF values between PD and PS. In addition, we determined correlation between MIBG parameters and each rCBF value. Finally, we compared the diagnostic ability for the differentiation of PD from PS between two diagnostic criteria, each MIBG index abnormality alone [heart-to-mediastinum ratio, H/M (E) < 1.9, H/E (D) < 1.7, washout rate > 40%] and each MIBG index abnormality or occipital lobe hypoperfusion (<36 ml/100 g per min). RESULTS: Absolute rCBF value of occipital lobe was significantly lower in severe PD as compared with PS or mild PD. In the correlation analysis, rCBF of occipital lobe correlated positively with MIBG parameters (H/M). Regarding the diagnostic ability, sensitivity improved by accounting for occipital hypoperfusion as compared with MIBG indices alone. In contrast, neither specificity nor accuracy improved by adding occipital lobe analysis. CONCLUSIONS: MIBG parameters (H/M) correlated positively with occipital hypoperfusion in PD. In the differential diagnosis between PD and PS, although its usefulness might be limited, analysis of rCBF in the occipital lobe added to (123)I-MIBG myocardial imaging can be recommended.

Assessment of diastolic function using 16-frame 201Tl gated myocardial perfusion SPECT: a comparative study of QGS2 and pFAST2.

OBJECTIVE: The objective of the present study is to investigate the correlations across various types of interface software for (201)Tl gated myocardial perfusion SPECT (MPS) in calculating two common diastolic function parameters (DFx), peak-filling rates (PFR), and time-to-peak filling (TTPF). METHODS: A total of 109 patients (66 men and 43 women; age 35-78 years) were studied. All patients were classified into three groups (i.e., ND, no-defect group; SD, small-defect group; LD, large-defect group) to clarify the influence of perfusion defects possibly affecting the analysis. Two kinds of available software, namely, quantitative gated SPECT (QGS2) and perfusion and functional analysis for gated SPECT (pFAST2) with cardioGRAF were used to obtain PFR and TTPF. Finally, we analyzed the correlation between DFx obtained with the two different kinds of software. RESULTS: The values of LVEF, PFR, and TTPF were assessed in all patients. In both the ND (correlation coefficients were 0.92, 0.79, and 0.99, respectively) and SD groups (correlation coefficients were 0.74, 0.88, and 0.98, respectively), a strong correlation was observed. In contrast, PFR did not show a significant correlation in the LD group. CONCLUSIONS: With the two different kinds of software, QGS2 and pFAST2, the calculated PFR was almost equal and showed good correlations in both ND and SD groups. In contrast, the numerical value varied between the two methods, and its correlation was poor in the LD group. However, TTPF showed a good correlation regardless of the presence of perfusion defects, and the values were equal. TTPF was confirmed to be a stable diastolic index across the two kinds of software, QGS2 and pFAST2, in (201)Tl gated MPS.

Do TSH, FT3, and FT4 Impact BAT Visualization of Clinical FDG-PET/CT Images?

Objective: We retrospectively analyzed activated BAT visualization on FDG-PET/CT in patients with various conditions and TH levels to clarify the relationships between visualization of BAT on FDG-PET/CT and the effect of TH. Methods: Patients who underwent clinical FDG-PET/CT were reviewed and we categorized patients into 5 groups: (i) thyroid hormone withdrawal (THW) group; (ii) recombinant human thyrotropin (rhTSH) group; (iii) hypothyroidism group; (iv) hyperthyroidism group; and (v) BAT group. A total of sixty-two FDG-PET/CT imaging studies in fifty-nine patients were performed. To compare each group, gender; age; body weight; serum TSH, FT3, and FT4 levels; and outside temperature were evaluated. Results: No significant visualization of BAT was noted in any of the images in the THW, rhTSH, hypothyroidism, and hyperthyroidism groups. All patients in the BAT group were in a euthyroid state. When the BAT-negative and BAT-positive patient groups were compared, it was noted that the minimum and maximum temperature on the day of the PET study and maximum temperature of the one day before the PET study were significantly lower in BAT-positive group than in all those of other groups. Conclusions: Elevated TSH condition before RIT, hyperthyroidism, or hypothyroidism did not significantly impact BAT visualization of clinical FDG-PET/CT images.

Relationship between cancer cell proliferation, tumour angiogenesis and 201Tl uptake in non-small cell lung cancer.

PURPOSE: To investigate whether 201Tl uptake is associated with cell proliferation and angiogenesis in non-small-cell lung carcinoma (NSCLC). METHODS: Eighty-four patients with scheduled NSCLC underwent 201Tl single photon emission computed tomography (SPECT) imaging: 15 min (early scan) and 240 min (delayed scan) after intravenous injection of 111 MBq of 201Tl chloride. 201Tl indices were calculated on early images (early ratio: ER) and delayed images (delayed ratio: DR). The retention index (RI) was also calculated from these two parameters. Using surgically resected cancer specimens (54 adenocarcinoma, 24 squamous cell carcinoma (SCC), six large-cell carcinoma), immunohistochemical stains for both Ki-67 (MIB-1 index) and CD34 were performed to examine the proliferative activity and the micro-vessel density (MVD), respectively. RESULTS: The mean value of 201Tl index was 1.69+/-0.77 (ER) and 2.31+/-1.08 (DR). The average RI was 42.6+/-42.9%, respectively. Both DR and RI positively correlated with MIB-1 index (r = 0.68, P < 0.05 and r = 0.52, P < 0.05). When we analyse adenocarcinoma and SCC separately, there was a significant positive correlation (r = 0.62, P < 0.05) between RI and MIB-1 index in adenocarcinoma but not in SCC (r = 0.20, P = NS). The value of ER positively correlated with MVD (r = 0.75, P < 0.05). It demonstrated strong positive correlation with both histological types (adenocarcinoma: r = 0.80, P < 0.05, SCC: r = 0.66, P < 0.05). CONCLUSION: 201Tl SPECT imaging is effective non-invasive method for assessing both the proliferation and the angiogenesis in NSCLC. Both DR and RI are useful indicators for assessing cancer cell proliferation in lung adenocarcinoma. ER is a useful marker for assessing the tumour angiogenesis in NSCLC.

Alteration of regional cerebral blood flow in patients with chronic pain--evaluation before and after epidural spinal cord stimulation.

BACKGROUND: Chronic pain is defined as intractable pain caused by abnormal pain transmission or impairment of the pain control system per se. Alteration of regional cerebral blood flow (rCBF) is known to occur under the presence of pain stimulation. Epidural spinal cord stimulation (SCS) is occasionally effective in relieving the symptom. OBJECTIVE: The aim of the current study is to investigate the alteration of rCBF in baseline condition and to find the association between the rCBF change and the efficacy of SCS in chronic pain. METHODS: A total of 18 patients underwent Tc-99m-HMPAO SPECT before and after SCS. Analysis with three-dimensional stereo-tactic surface projections (3D-SSP) with stereo-tactic extraction estimation (SEE) software was adopted to evaluate the rCBF. We assessed the extent score of the abnormal region in each segment (rate of the coordinates with a Z-value that exceeds three kinds of threshold value 2.0, 2.5 and 3.0 in all coordinates within a segment). According to the therapeutic response defined by visual analogue scale, we categorized patients into two groups, the good responder (GR) group (n=12) and poor responder (PR) group (n=6). In the analysis, we compared the extent score in the following two conditions. (1) Comparison between the PR group and normal control group under both baseline condition and after SCS. (2) Comparison between the GR group and normal control group under both baseline condition and after SCS. RESULTS: (1) In the PR group, increased rCBF was observed in left thalamus, bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, the range of these increased rCBF areas localized but remained. Decrease of rCBF was noted in bilateral subcallosal gyrus, superior temporal gyrus (STG) and bilateral anterior cingulate gyrus (ACG). They localized after SCS, but remained. (2) In the GR group, increased rCBF areas were noted in bilateral precuneus and bilateral cerebellum under the baseline condition. After SCS, they localized in bilateral precuneus but those of bilateral cerebellum remained. Decreased rCBF area was noted in bilateral subcallosal gyrus, STG and bilateral ACG under the baseline. After SCS, they localized in bilateral subcallosal gyrus and bilateral STG. In contrast, they enlarged in bilateral ACG. CONCLUSION: Chronic pain patients demonstrated abnormal rCBF distribution on both baseline and post SCS conditions. Increased rCBF of thalamus and precuneus under both conditions in the PR group and decreased rCBF of ACG under post SCS conditions in the GR group were characteristic patterns. Tc-99m-HMPAO SPECT with 3D-SSP and SEE analysis is likely objective and effective in monitoring and evaluating therapeutic outcome by SCS in chronic pain. In addition, it provides information that is useful in the selection of SCS candidates.

Cerebral blood flow abnormalities induced by transient hypothyroidism after thyroidectomy--analysis by tc-99m-HMPAO and SPM96.

UNLABELLED: The current study is an investigation of alterations in regional cerebral blood flow (rCBF) distribution in patients with transient hypothyroidism after thyroidectomy. In addition, the effects of thyroxine treatment on rCBF changes were studied. METHODS: Noninvasive rCBF measurements using 99mTc-HMPAO SPECT were performed on 24 post-thyroidectomy patients who were in a hypothyroidic state. The measurements were conducted before 131I therapy and after thyroid hormone (thyroxine) replacement. We used adjusted rCBF images (normalization of global CBF for each subject to 50 ml/100 g/min with proportional scaling) to compare these data with age-matched normal control groups (n =15) using SPM96. We also compared the absolute rCBF value of hypothyroidic patients with those of normal control groups. In addition, the association between rCBF alteration and the severity of depression was also analyzed. Finally, the effect of thyroid hormone replacement on rCBF was investigated individually using the Jack-knife test, in which patient data were compared with those from healthy volunteers. According to the result of this test, all cases were categorized into three subgroups, namely, improved, unchanged group and normal. To prove the reversibility of rCBF alteration after thyroid hormone replacement, a group comparison test between the normal controls and the improved group was done before and after thyroid hormone replacement. Similarly a group comparison test between the unchanged group and normal controls was also performed. RESULTS: In the hypothyroidic condition, there was a significant decrease in the posterior part of the bilateral parietal lobes and in part of the bilateral occipital lobes, including the cuneus. These decreased rCBF areas extended to the bilateral prefrontal cortices as deterioration became more profound. On individual analysis, 16 of 24 patients (66.7%) demonstrated rCBF reduction, while 8 patient did not show significant rCBF change (33.3%, the normal group). After thyroxine replacement, improvement of rCBF was noted in nine of 16 patients (56.3%, the improved group). In seven of 16 patients (43.7% the unchanged group), the significant low rCBF area remained unchanged. Compared with the normal controls, the improved group showed significantly decreased rCBF of the bilateral parietal lobe and the occipital lobe in the hypothyroic condition. After thyroid hormone replacement, these abnormal rCBF areas disappeared. In contrast, in the unchanged group, the significant hypoperfusion area became localized but remained. CONCLUSION: 99mTc-HMPAO SPECT and SPM96 analysis demonstrated a significant rCBF decrease in the parietal lobe and part of the occipital lobe in patients with induced transient hypothyroidism after thyroidectomy. This phenomenon might contribute to understanding of the depressive state. Recovery of rCBF after thyroid hormone replacement was confirmed in some patients. However, rCBF improvement did not always occur in every patient during the follow up period. The reversibility of rCBF in transient hypothyroidism may be dependent on individual characteristics during a short-term period.

[The development of new method for the assessment of perfusion reserve using split dose iodine-123-IMP SPECT: one-day protocol by modified ARG method].

Evaluation of the regional cerebrovascular reactivity (rCVR) to a cerebral vasodilatory stimulus is important in the investigation of patients with ischemic cerebrovascular disease. We devised a simplified one-day protocol technique using [123I]N-isopropyl-p-iodoamphetamine (IMP) autoradiography (ARG) with SPECT. To validate the accuracy of IMP-ARG for quantifying rCVR to acetazolamide, we compared rCVR measured using IMP-ARG with rCVR calculated using IMP split dose method of microsphere model. Twenty patients with chronic steno-occlusive disease in a unilateral major cerebral artery underwent 123I-SPECT. On rCBF SPECT image above 3.5 cm from OM line, large cortical regions of interest (ROI) was bilaterally determined for bilateral middle cerebral artery and anterior cerebral artery. Based on rCBF values in each ROI, rCVR to acetazolamide was calculated. Significant correlation was observed between rCVR values obtained using IMP-ARG and microsphere model IMP methods in the 80 ROIs examined in the 20 patients (r = 0.72; p < 0.001). The result demonstrated that [123I]IMP-ARG split dose method can quantify rCVR non-invasively in a short time.

[Usefulness of 201Tl SPECT in the predication of mediastinal lymph nodes metastasis in patients with non small cell lung carcinoma (NSCLC)].

Predictivity of mediastinal lymph nodes metastasis of 201Tl SPECT were examined before operation in 113 patients with non-small cell lung cancer (69 adenocarcinoma, 31 squamous cell carcinoma, 10 large cell carcinoma, 2 bronchiolo-alveolar carcinoma, 1 neuroendocrine cell carcinoma). Patients were classified into two groups, with or without lymph nodes metastasis according to the pathological diagnosis. We calculated parameters of 201Tl SPECT early ratio, delayed ratio, retention index (RI) and maximal diameters. In addition, we calculated optimal cut-off value of RI to estimate the mediastinal lymph nodes metastasis. Mediastinal lymph nodes metastasis was confirmed pathologically in 62 patients. ER and DR did not show any statistical significance between two groups. Maximal diameters of primary tumor were also comparable between two groups. RI was significantly higher in mediastinal lymph node metastasis positive group compared to that in mediastinal lymph node metastasis negative group. The sensitivity (Sen), specificity (Spe), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Acc) of 201Tl SPECT were 82.2%, 82.3%, 85.0%, 79.2% and 82.3%. These parameters were similar of higher than 72.6%, 82.4%, 83.3%, 71.2% and 77.0% of chest CT. The RI of 201Tl SPECT was useful tool for predicting lymph nodes metastasis in non-small cell lung cancer. The optimum cut-off value of RI in the prediction of mediastinal lymph nodes metastasis was 35%. We should take into account of upstaging in cases with higher RI (>35%).

The usefulness of (18)F-FDG PET/MRI fusion image in diagnosing pancreatic tumor: comparison with (18)F-FDG PET/CT.

PURPOSE: This study aimed at demonstrating the feasibility of retrospectively fused (18)F FDG-PET and MRI (PET/MRI fusion image) in diagnosing pancreatic tumor, in particular differentiating malignant tumor from benign lesions. In addition, we evaluated additional findings characterizing pancreatic lesions by FDG-PET/MRI fusion image. METHODS: We analyzed retrospectively 119 patients: 96 cancers and 23 benign lesions. FDG-PET/MRI fusion images (PET/T1 WI or PET/T2WI) were made by dedicated software using 1.5 Tesla (T) MRI image and FDG-PET images. These images were interpreted by two well-trained radiologists without knowledge of clinical information and compared with FDG-PET/CT images. We compared the differential diagnostic capability between PET/CT and FDG-PET/MRI fusion image. In addition, we evaluated additional findings such as tumor structure and tumor invasion. RESULTS: FDG-PET/MRI fusion image significantly improved accuracy compared with that of PET/CT (96.6 vs. 86.6 %). As additional finding, dilatation of main pancreatic duct was noted in 65.9 % of solid types and in 22.6 % of cystic types, on PET/MRI-T2 fusion image. Similarly, encasement of adjacent vessels was noted in 43.1 % of solid types and in 6.5 % of cystic types. Particularly in cystic types, intra-tumor structures such as mural nodule (35.4 %) or intra-cystic septum (74.2 %) were detected additionally. Besides, PET/MRI-T2 fusion image could detect extra benign cystic lesions (9.1 % in solid type and 9.7 % in cystic type) that were not noted by PET/CT. CONCLUSIONS: In diagnosing pancreatic lesions, FDG-PET/MRI fusion image was useful in differentiating pancreatic cancer from benign lesions. Furthermore, it was helpful in evaluating relationship between lesions and surrounding tissues as well as in detecting extra benign cysts.

Comparison of diagnostic and prognostic capabilities of ¹8F-FDG-PET/CT, ¹³¹I-scintigraphy, and diffusion-weighted magnetic resonance imaging for postoperative thyroid cancer.

PURPOSE: The first aim of this study was to compare the detectability of metastasis of postoperative differentiated thyroid cancer (DTC) among (131)I whole body scintigraphy (IWBS), fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT), and diffusion-weighted magnetic resonance imaging (DWI). The second aim was to clarify the association between the image pattern and prognosis. MATERIALS AND METHODS: We evaluated 70 postoperative DTC patients on both a patient basis and an organ basis (lymph nodes, lung, bone), and we analyzed the correlation between the image pattern and the prognosis. RESULTS: For the patient-basis analysis, the detectability by IWBS, PET/CT, and DWI was 67.1%, 84.2%, and 57.6%, respectively. IWBS provided complementary information to that provided by PET/CT in 11 of 70 (15.7%) cases. For the organ-basis analysis, IWBS was the best detector for lymph node metastasis (72.4%). PET/CT was superior to IWBS for detecting metastasis of bone (85.7% vs. 71.4%) and lung (94.1% vs. 62.7%). For the correlation analysis, PET and DWI positivity were the factors predicting a poor prognosis. CONCLUSION: PET/CT was the best modality for detecting metastases in postoperative DTC patients, although IWBS provided complementary information. Because PET/CT and DWI gave similar information (e.g., positivity) suggesting poor prognoses, the combination of IWBS and DWI might be the method of choice for monitoring postoperative DTC.

The reproducibility of deep-inspiration breath-hold (18)F-FDG PET/CT technique in diagnosing various cancers affected by respiratory motion.

BACKGROUND: The deep-inspiration breath-hold PET/CT (DIBH PET/CT) technique improves the limitations of diagnosing a lesion located in an area influenced by respiratory motion that results in spatial misregistrations caused by respiration between PET and CT. However, its reproducibility with regard to calculating the maximal standardized uptake value (SUV(max)) and metabolic volume (MV) in DIBH PET/CT has not been elucidated. OBJECTIVE: The purpose of this study was to investigate the reproducibility of the DIBH PET/CT technique including calculating the SUV(max) and the MV. METHODS: Sixty patients with various cancers were enrolled. The subjects had 47 abdominal lesions and 28 chest lesions. All patients demonstrated a misregistered image in the early whole-body image taken 50 min after FDG intravenous infusions. We added the delayed spot images 40 min after the first image. On the delayed image, we performed both conventional techniques with non-breath-hold (NBH) and the DIBH technique. In the four times DIBH technique, we obtained the coefficient of variance (CV) in calculating these indices for evaluating reproducibility. RESULTS: The SUV(max) value with DIBH showed an increase of 16.1-60.1% compared with that measured by NBH. The mean value of CV was 5.5 in thoracic lesions and 6.3 in abdominal lesions. The values of MV with DIBH showed a decrease of 14.0-20.1% compared with those measured by NBH. Regarding reproducibility, mean value of CV was 7.1 in thoracic lesions and 11.9 in abdominal lesions. CONCLUSION: The DIBH technique improves the inaccurate quantification of both SUV(max) and MV. Although the CV value of SUV(max) with DIBH technique is better in thoracic lesions compared with that in abdominal lesions, the reproducibility was acceptable.

Predictive value of Tc-99m galactosyl human serum albumin liver SPECT on the assessment of functional recovery after partial hepatectomy: a comparison with CT volumetry.

OBJECTIVE: Predicting liver functional reserve is important before partial hepatectomy. However, it is difficult to predict using morphologic imaging modalities, such as CT and MRI. In this study, we assess the usefulness of galactosyl human serum albumin (GSA) scintigraphy in predicting liver function recovery. METHODS: We performed 99mTc-GSA scintigraphy before operation in 56 patients. Each patient was administered 185 MBq of 99mTc-GSA by intravenous injection. Serial images were taken immediately after the administration for 40 min. SPECT images were obtained to make a functional map. We calculated the functioning parameter residual GSA-Rmax (GSA-RL) using analysis software developed by Dr.N. Shuke. In addition, we compared GSA-RL with the morphological parameter residual liver volume (RLV-CT) calculated by conventional CT and serum albumin (Alb) or cholinesterase (ChE). We analyzed the correlation between imaging parameters and the postoperative recovery periods of serum albumin (r-Alb) and cholinesterase (r-ChE) and the values at 1 and 3 months for serum albumin (1M-Alb, 3M-Alb) and cholinesterase (1M-ChE, 3M-ChE). RESULTS: We found significant correlations between GSARL and r-Alb, r-ChE, 1M-Alb, 3M-Alb, 1M-ChE and 3M-ChE, but not between RLV-CT and the same parameters. CONCLUSION: The GSA-RL calculated by 99mTc GSASPECT was a useful parameter for predicting postoperative liver function recovery that should be implemented before partial hepatectomy.