Intravascular ultrasound correlates with coronary flow reserve and predicts the survival in angiographically normal cardiac transplant recipients

OBJECTIVES

We aimed to determine whether epicardial and intramyocardial arteries were involved concordantly in early cardiac allograft vasculopathy.

METHODS

Thirty consecutive recipients who had received cardiac transplantation more than 1 year before and had a normal coronary angiogram were enrolled for intravascular ultrasound (IVUS), fractional flow reserve, coronary flow reserve and dipyridamole thallium-201 single photon emission computed tomography. Graft failure including cardiac death and retransplantation served as the primary outcome.

RESULTS

Plaque volume index and maximum area stenosis calculated from IVUS measurements correlated with coronary flow reserve deterioration in a subgroup of patients with normal fractional flow reserve (n = 13; r = -0.80, p = 0.001 and r = -0.91, p <0.0001, respectively). After follow-up for 18.4 +/- 7.6 months, maximum area stenosis was found to be an independent predictor of graft failure (hazard ratio 1.43, 95% confidence interval 1.08-1.89, p = 0.012).

CONCLUSION

In patients with physiologically normal epicardial coronary arteries, impairment of microvascular integrity correlates with the plaque burden measured by IVUS, suggesting the concordant involvement of both epicardial and resistant vessels in early cardiac allograft vasculopathy. Evident epicardial coronary narrowing on IVUS may predict graft failure in spite of normal coronary angiograms.

Characterization of plaques using 18F-FDG PET/CT in patients with carotid atherosclerosis and correlation with matrix metalloproteinase-1

High tissue matrix metalloproteinase (MMP) activity has been associated with advanced atherosclerosis and plaque rupture. 18F-FDG uptake has been reported to detect inflammation. This investigation examined the vascular 18F-FDG uptake by PET/CT and its correlation with circulating MMP-1 levels.

METHODS

We examined 25 consecutive patients with significant carotid stenosis and 22 healthy control subjects using 18F-FDG PET/CT. The leukocyte counts, C-reactive protein (CRP), and MMP-1 were measured.

RESULTS

18F-FDG arterial uptake, as well as calcifications, was significantly higher in extensive distributions in patients with established carotid stenosis. However, their distribution was not consistently overlapping. The values of circulating MMP-1 and leukocyte counts were significantly higher in patients with carotid stenosis (all P < 0.05). In addition, subjects with higher 18F-FDG uptake (maximum SUV > 2.0) in target lesions had higher baseline and poststenting MMP-1 levels (all P < 0.05).

CONCLUSION

We provide a link between 18F-FDG uptake and circulating MMP-1. 18F-FDG PET/CT could be used as an adjunct to the clinical management of high-risk atherosclerosis and an in vivo tool to study plaque biology.

Extensive scar myocardium in hypertrophic cardiomyopathy with severe myocardial bridge

We present a patient with hypertrophic cardiomyopathy and a large scar in the apex demonstrated on 201Tl SPECT and 18F-FDG PET images. Subsequent coronary angiography revealed no significant coronary artery stenosis but a myocardial bridge with severe systolic milking in the middle segment of the left anterior descending artery.

Whole-body F-18 FDG PET for hepatocellular carcinoma patients after interventional treatment

For hepatocellular carcinoma (HCC) patients after primary treatment, conventional anatomical imagings may not be reliable in detecting residual, recurrent or metastatic lesions. The aim of this retrospective study was to evaluate the usability of FDG PET in the follow-up of HCC patients after prior interventional treatments. The database consisted of 10 male and 2 female (age range, 46-82 years; mean age, 63.4 +/- 11.7 years) who had received primary HCC treatments and underwent FDG PET scans at the National Taiwan University Hospital. The accuracy of FDG PET detection was determined by the histopathological results or other clinical evidences afterwards. Of the 22 lesions, FDG PET studies were able to detect 8 (8/10, 80%) intrahepatic lesions and 8 (8/12, 66.7%) extrahepatic lesions. The lesion based detection rate of FDG PET is 72.7% (16/22). FDG PET was able to detect at least 1 lesion in 11 patients. The 6 false negative lesions in 6 patients include 2 intrahepatic lesions, 1 brain lesion, 1 sphenoid sinus lesion and 2 multiple subcentimeter pulmonary lesions. FDG PET scan is able to provide valuable auxiliary information for the follow up of HCC patients clinically suspicious of recurrence if their conventional image findings are not unambiguous.

99mTc-HL91 is inferior to 201Tl in scintigraphic detection of chronic myocardial ischaemia

AIM

99mTc-HL91 is a new hypoxia agent and can identify acutely ischaemic viable myocardium in a canine model using a standard gamma camera. The purpose of the study was to determine whether this tracer could be used to detect regional ischaemia in chronic ischaemic myocardium in a swine model.

METHOD

Using a porcine model of chronic myocardial ischaemia, five mini-pigs with proximal left anterior descending artery (LAD) stenoses were studied. Injection of 462.5 MBq (12.5 mCi) 99mTc-HL91 was followed by imaging over 2 h. Coronary angiography and dipyridamole stress-re-injection 201Tl single photon emission computed tomography (SPECT) were performed within 1 day of each other.

RESULTS

None of the five pigs demonstrated positive hot 99mTc-HL91 uptake throughout the 2 h imaging, whereas four of the five animals showed significant myocardial ischaemia on 201Tl SPECT. The region of interest analysis of LAD/left circumflex artery count ratios at 1 and 2 h demonstrated similar 99mTc-HL91 uptake and retention in chronic ischaemic as well as non-ischaemic myocardium.

CONCLUSION

99mTc-HL91 is inferior to 201Tl in scintigraphic detection of chronic myocardial ischaemia.

Early detection of splenic metastasis of lung cancer by 18F-2-fluoro-2-deoxyglucose positron emission tomography

Diagnosis of splenic involvement by lung cancer in the early stage is helpful for introducing proper treatment. We report a case of pulmonary adenocarcinoma with splenic metastasis which was first detected by 18F-2-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET). This 56-year-old male underwent left pneumonectomy, extensive lymph node dissection and postoperative adjuvant chemotherapy and radiotherapy. Because progressive elevation of carcinoembryonic antigen was detected 2 years after the operation, whole-body 18F-FDG PET was performed and revealed an 18F-FDG hypermetabolic spot in the splenic hilum. Although subsequent computed tomography (CT) did not reveal any lesions in the spleen, the second and third CT scans performed 10 and 13 months later confirmed the previous PET finding of splenic metastasis. This case suggests that 18F-FDG PET may be useful for early detection of splenic metastasis not visible on CT.

Early restaging whole-body 18F-FDG PET during induction chemotherapy predicts clinical outcome in patients with locoregionally advanced nasopharyngeal carcinoma

PURPOSE

This study was undertaken to evaluate the utility of whole-body (18)F-FDG PET in monitoring therapeutic effect during induction chemotherapy (IC) and in predicting prognosis in patients with locoregionally advanced nasopharyngeal carcinoma (NPC).

METHODS

Fifty patients who had histologically proven, locoregionally advanced NPC without distant metastasis and had received IC were recruited in this study. The study cohort consisted of 19 females and 31 males (age 17-72 years, mean 45.9+/-11.9). Whole-body (18)F-FDG PET was performed in each patient after completion of one (33 patients) or two (17 patients) courses of IC. Each patient was restaged on the basis of the (18)F-FDG PET results. Patients who were downstaged to stage I or II were classified as major responders; the rest were classified as non-major responders.

RESULTS

Only 1 of the 23 major responders subsequently developed local recurrence. At the time of data analysis, all major responders were alive; by contrast, of the 27 non-major responders, 15 had locoregional recurrence or distant metastasis and nine had died (seven of NPC and two of treatment-related complications). Kaplan-Meier survival analysis showed significantly longer recurrence-free survival and overall survival in major responders (56.4+/-9.2 and 58.1+/-2.2 months) as compared with non-major responders (33.7+/-23.2 and 44.7+/-20.0 months), with p<0.0001 and p=0.0024, respectively.

CONCLUSION

The results of this study suggest that early restaging by a single whole-body (18)F-FDG PET scan after the first or second course of IC is useful for predicting therapeutic response and outcome in patients with locoregionally advanced NPC.

Whole-body 18F-FDG PET in recurrent or metastatic nasopharyngeal carcinoma

The aim of this retrospective study was to evaluate the sensitivity and prognostic significance of whole-body (18)F-FDG PET for nasopharyngeal carcinoma (NPC) patients for whom there was a suspicion of recurrence or metastasis by conventional radiologic or clinical findings during their follow-up examinations.

METHODS

Whole-body (18)F-FDG PET examinations were performed on 64 Taiwanese NPC patients (14 female, 50 male; mean age +/- SD, 45.8 +/- 13.0 y; age range, 16-75 y) 4-70 mo (mean +/- SD, 14.1 +/- 13.5 mo) after radiotherapy or induction chemotherapy followed by concurrent chemoradiotherapy from February 1997 to May 2001. The accuracy of (18)F-FDG PET detection for each patient was determined by the histopathologic results or other clinical evidence.

RESULTS

The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of (18)F-FDG PET images in the diagnosis of NPC recurrence or metastases and secondary primary cancers were 92%, 90%, 92%, 90%, and 91%, respectively. Furthermore, the presence of (18)F-FDG hypermetabolism was highly correlated with the survival time of NPC patients.

CONCLUSION

Whole-body (18)F-FDG PET is a sensitive follow-up diagnostic tool for the evaluation of NPC recurrences and metastases. It is also an effective prognostic indicator for NPC patients. To determine the optimized utilization of (18)F-FDG PET in the follow-up for NPC patients, further cost-effectiveness analysis of (18)F-FDG PET in combination with conventional management is necessary.

Gastric emptying function changes in patients with thyroid cancer after withdrawal of thyroid hormone therapy

BACKGROUND

Hypothyroidism is commonly thought to cause decreased gastric emptying but is mostly associated with autoimmune disease. In the present study the gastric emptying function of thyroid cancer patients with severe hypothyroidism of short duration was evaluated with a radionuclide solid meal gastric emptying study.

METHODS

Twenty-two patients who had undergone surgical operation and (131)I ablation for thyroid cancer participated in solid meal gastric emptying studies before the withdrawal of thyroxine and then again 4 weeks after the withdrawal of thyroxine. Eleven patients had an additional gastric emptying study at 6 weeks after withdrawal of thyroxine. Gastric emptying curves and emptying parameters were calculated. Student's paired t-test was used for statistical analysis of data for all cases between the baseline and at 4 weeks after withdrawal. An additional repeated measure anova with multiple comparisons was performed on data between baseline, 4 weeks and 6 weeks after withdrawal for the other 11 patients. All P values presented are two-tailed and the significance level is 0.05.

RESULTS

Hypothyroidism status was confirmed by the marked change of the serum thyroxine and thyroid-stimulating hormone 4 weeks and 6 weeks after withdrawal of the thyroxine replacement (P < 0.001). The gastric half-emptying time and emptying rate changed significantly after short-term severe thyroid hormone deficiency (P < 0.005). However, the length of the lag phase did not have a statistically significant change at 4 weeks or 6 weeks after withdrawal of the thyroxin replacement (P = 0.219 and 0.142).

CONCLUSIONS

Hypothyroidism following the withdrawal of the thyroxine replacement in thyroid cancer patients preparing for (131)I cancer work-up can significantly prolong gastric half-emptying time and emptying rate.

Characterization of the binding sites for 123I-ADAM and the relationship to the serotonin transporter in rat and mouse brains using quantitative autoradiography

Imaging of serotonin transporter (SERT) in the central nervous system may provide an important tool to evaluate some psychiatric disorders. Recently, a novel (123)I-labeled radiotracer, 2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine ((123)I-ADAM), has been developed that exhibited a high selectivity for SERT. The aim of this study was to characterize the biodistribution and specificity of (123)I-ADAM to SERT using quantitative autoradiography in both control and neurotoxin-treated animals.

METHODS

(123)I-ADAM (74 MBq) was injected intravenously into the mice to access its biodistribution in the brain via quantitative autoradiography. Further, rats with serotonin depleted by intraperitoneal injection of p-chloroamphetamine (PCA) were used to evaluate the specificity of (123)I-ADAM to SERT. The levels of biogenic amines were then measured and correlated with quantitative (123)I-ADAM labeling in control and PCA-treated rat brains.

RESULTS

The autoradiographic results showed that (123)I-ADAM accumulated in SERT-rich brain areas after systemic injection, including the globus pallidus, thalamus, hypothalamus, substantia nigra, interpeduncular nucleus, amygdala, and raphe nucleus. The dorsal raphe nucleus had the highest initial uptake with a peak specific binding ratio (i.e., [target - cerebellum]/cerebellum) at 120 min after injection. (123)I-ADAM uptake was dramatically decreased in the hippocampus, thalamus, amygdala, geniculate nuclei, hypothalamus, raphe nucleus, and substantia nigra in PCA-lesioned rats. The decrement in radioactivity was more prominent at higher dosages of PCA and was in parallel with the changes in amounts of serotonin and 5-hydroxyindoleacetic acid in the prefrontal cortex.

CONCLUSION

This study demonstrates that regional distribution of (123)I-ADAM radioactivity is similar to the SERT localization in both rat and mouse brains. We also validated that destruction on central serotonergic neurons after PCA treatment inhibits the uptake of (123)I-ADAM in serotonin-rich brain regions. High specific binding to SERT in vivo makes (123)I-ADAM an appropriate radiotracer for solitary studies of serotonin functions in living humans.

Sensitivity and specificity of 99mTc-TRODAT-1 SPECT imaging in differentiating patients with idiopathic Parkinson's disease from healthy subjects

The imaging of dopamine transporter (DAT) with (99m)Tc-TRODAT-1 ([2-[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]methyl](2-mercaptoethyl)amino]ethyl]amino]ethanethiolato(3-)-N2,N2',S2,S2']oxo-[1R-(exo-exo)]-(99m)Tc-technetium) and SPECT has been recently proposed to be a valuable and feasible means of assessment of the integrity of dopamine neurons. The purpose of this study was to further investigate the clinical correlations and the age-specific sensitivity and specificity of this new approach in the diagnosis of patients with idiopathic Parkinson's disease (PD) that manifests in patients >50 y of age.

METHODS

SPECT imaging with (99m)Tc-TRODAT-1 was conducted in 78 consecutive PD patients and in 40 age-matched healthy subjects. The images were obtained 4 h after the intravenous injection of the tracer. The ratios of specific striatal binding to nonspecific occipital binding were calculated. S/O represents the ratio for whole striatal binding, whereas P/O and C/O represent the putamen and caudate nucleus, respectively. Statistical analyses of the sensitivity and specificity of these ratios in different age-specific subgroups were performed. The correlations between these ratios and clinical assessments were also analyzed. The age-related declines in the striatal binding in both patients and controls were given particular focus.

RESULTS

The S/O, C/O, and P/O ratios decreased significantly both contralaterally and ipsilaterally to the dominant symptomatic side in the PD group (P < 0.0001). The mean reduction of binding was found in the order of putamen (contralateral side, -81%; ipsilateral side, -67%) and caudate nucleus (contralateral side, -46%; ipsilateral side, -40%). The sensitivity and specificity of both P/O and S/O ratios were 100% in discriminating PD patients from healthy subjects in the age-specific groups. The binding ratios correlated negatively with the Unified Parkinson's Rating Scale and Hoehn and Yahr (H-Y) staging. Of particular interest, the binding of the striatum contralateral to the asymptomatic side in H-Y stage I patients also decreased significantly. The age-related decline of these ratios was significant in the control group.

CONCLUSION

We have demonstrated that (99m)Tc-TRODAT-1 SPECT has a high sensitivity and specificity for measuring the decrement of DAT in PD patients. In addition to its wide availability, we suggest that this new approach may serve as a diagnostic marker for PD.

99mTc-TRODAT-1 imaging of multiple system atrophy

Using (99m)Tc-TRODAT-1 ((99m)Tc-[2[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]-oct-2-yl]-methyl](2-mercaptoethyl) amino]ethyl]amino]ethane-thiolato(3-)-N2,N2',S2,S2]oxo-[1R-(exo-exo)])) brain SPECT imaging, we measured striatal dopamine transporters (DATs) activity in multiple system atrophy (MSA) to investigate the possibility of differentiating it from Parkinson's disease (PD) and to correlate the findings with the parkinsonian (MSA-P) and cerebellar (MSA-C) subtypes of MSA.

METHODS

Forty-nine patients with probable MSA (30 MSA-P, 19 MSA-C), a disease control group of 36 age- and disease duration-matched patients with probable PD, and a healthy control group of 33 age-matched healthy volunteers participated in a SPECT study. The ratios of specific striatal binding-to-nonspecific occipital binding, including the striatum-to-occipital ratio (S/O), putamen-to-occipital ratio (P/O), caudate nucleus-to-occipital ratio (C/O), and putamen-to-caudate nucleus ratio (P/C), were calculated. The statistical analyses of uptakes among 4 groups used ANOVA followed by Games-Howell's multiple comparisons. The Spearman correlation coefficient between the motor scores of Unified Parkinson's Disease Rating Scale (UPDRS-III) and those binding ratios of the MSA-P and MSA-C groups and the PD group was also performed.

RESULTS

The striatal binding was more symmetrically reduced in the MSA-P (asymmetric index, 14.2) and MSA-C (asymmetric index, 8.1) groups, in contrast to the greater asymmetric reduction in the PD group (asymmetric index, 28.6). Overall striatal binding was significantly reduced in the MSA-P (-59.8%), MSA-C (-29.9%), and PD (-58.0%) groups with no overlap between these values and those of the control group. Like the PD group, bilateral P/O, C/O, and S/O ratio values were significantly reduced in the MSA-P and MSA-C groups. Nevertheless, the reduction of bilateral P/O and S/O ratios was more for the MSA-P group than for the MSA-C group. P/C ratios showed that the MSA-P and PD groups had similar patterns of nigral impairment, but the MSA-C group had a different pattern. No correlation between the UPDRS-III scores and (99m)Tc-TRODAT-1 bindings was found in both MSA-P and MSA-C groups; in contrast, a significant negative correlation was noted in the PD group.

CONCLUSION

(99m)Tc-TRODAT-1 brain SPECT is capable of scientifically differentiating between the MSA-P and MSA-C subtypes, and MSA-P has more symmetric nigrostriatal damage than that in PD. (99m)Tc-TRODAT-1 brain SPECT imaging probably could provide important information to differentiate MSA from PD.

Lymphoscintigraphy and intraoperative gamma probe-directed sentinel lymph node mapping in patients with malignant melanoma

BACKGROUND AND PURPOSE

Lymphoscintigraphy has been considered a useful tool for sentinel lymph node (SLN) mapping for malignant melanoma. This study evaluated the usefulness of SLN detection by lymphoscintigraphy and excision with intraoperative gamma probe in Taiwanese patients with malignant melanoma.

METHODS

Thirty six malignant melanoma patients in clinical stage I and II were enrolled. The Breslow thickness of the primary melanomas was </= 1.0 mm in 8 patients, 1.01 to 2.0 mm in 12 patients, 2.01 to 4.0 mm in 9 patients, >/= 4 mm in 3 patients, and unknown in 4 patients who were transferred from other hospitals and had no nodal or distant metastasis. SLN lymphoscintigraphy was performed with filtered 99mTc-sulfur colloid. An intraoperative gamma probe was used to identify the SLN for dissection.

RESULTS

A total of 44 SLNs were detected in 36 patients, with a mean of 1.22 SLNs per patient. The SLN detection rate by lymphoscintigraphy was 100%. During surgery, 39 of the 44 SLNs (88.6%) in 33 of 36 patients (91.7%) were identified. SLN metastasis was found in 8 of 39 dissected SLNs (20.5%) or in 8 of 36 patients (22.2%). The SLN metastatic rate in the patients with primary melanoma with Breslow thickness </= 2.0 mm was 10.0% (2/20), and in patients with Breslow thickness > 2.0 mm was 41.7% (5/12).

CONCLUSIONS

Lymphoscintigraphy and intraoperative gamma probe are useful in localizing and dissecting SLN in patients with malignant melanoma. SLN mapping changed the clinical stage in 22.2% of melanoma patients.

Dopamine transporter change in drug-naive schizophrenia: an imaging study with 99mTc-TRODAT-1

The aim of this study was to use a specific dopamine transporter (DAT) ligand, 99mTc-TRODAT-1 with single photon emission computed tomography (SPECT) to investigate the densities of DAT in the striatal dopaminergic system in patients with schizophrenia. Striatal DAT uptakes were measured in 12 drug-nai;ve schizophrenic patients and 12 age- and sex-matched healthy volunteers. The psychometric tools included the Standardized Clinical Assessment for Neuropsychiatry (SCAN) and the Positive and Negative Syndrome Scale (PANSS). Semiquantitative analyses using the ratio of uptake in caudate, putamen, and striatum to occipital lobe, and left-right asymmetry were performed. Decreased TRODAT uptake in the right striatum and increased uptake in the left striatum were found in the schizophrenics. However, there is no overall difference in the average striatum uptake. The right-left asymmetry of the caudate and putamen DAT binding seen in the healthy control group disappeared in the schizophrenia group. The decreased right uptake and increased left uptake in the striatum might lead to the lack of right-left asymmetry in neuroleptic-nai;ve schizophrenia patients, confirming that the disorder could be due to a disruption in brain lateralization. This is the first report on the use TRODAT to evaluate the DAT density in schizophrenia patients and shows lack of asymmetry in striatal uptake of TRODAT in schizophrenics. The findings also suggest that TRODAT SPECT may be a useful technique to measure dopamine transmission in the human brain and for understanding the pathophysiology of neuropsychiatric disorders.

Repeated gallium-67 scan demonstrating an occult mycotic aneurysm of the aortic arch due to Salmonella

A 71 y-old female with 40 degrees C fever and a change in consciousness during haemodialysis was referred for a gallium-67 scan, which revealed a horseshoe-like radioactive accumulation in the mediastinal region. Salmonella enteritidis was isolated from blood culture. Magnetic resonance imaging confirmed an aortic arch aneurysm. The patient died without surgery.

Improved diagnostic performance of thallium-201 myocardial perfusion scintigraphy in coronary artery disease: from planar to single photon emission computed tomography imaging

BACKGROUND

This study was performed to compare Tl-201 myocardial perfusion single photon emission computed tomography (SPECT) with planar scintigraphy in the diagnosis of coronary artery disease (CAD).

METHODS

Retrospectively, 240 of 3262 patients, with exercise-redistribution Tl-201 myocardial perfusion scintigraphy performed between January 1990 and October 1997, were analyzed to compare Tl-201 scintigraphy and coronary arteriography. Within 30 days, all 240 patients underwent both coronary arteriography and exercise-redistribution Tl-201 myocardial perfusion scintigraphy with 86 SPECT and 154 planar images acquired.

RESULTS

The sensitivities of Tl-201 myocardial perfusion scintigraphy in individual coronary arteries including left anterior descending (LAD) artery, left circumflex (LCX) artery, and right coronary artery (RCA), were 77%/72%, 31%/30%, and 77%/50% in the SPECT/planar study groups, respectively. The sensitivities of CAD detection in patients with single-vessel, double-vessel, and triple-vessel diseases were 96%/82%, 91%/85%, and 96%/90% in the SPECT/planar study groups, respectively.

CONCLUSION

SPECT images provide greater advantages over planar images for better detection of the number, location, and extent of CAD. Cardiac SPECT does improve the accurate interpretation in abnormal Tl-201 distributions due to the higher contrast resolution and better separation of overlapping myocardial regions.

The value of Tc-99m red blood cell SPECT in differentiating giant cavernous hemangioma of the liver from other liver solid masses

PURPOSE

Giant cavernous hemangioma (GCH) of the liver has the potential risk for rupture and bleeding, which may cause sudden death. The purpose of this retrospective study was to compare the value of Tc-99m-labeled red blood cell (RBC) SPECT with ultrasound (US) in differentiating GCH from other solid liver masses.

METHODS

Twenty-two patients with giant solid liver masses, equal to or greater than 8 cm in at least one dimension, identified by US were examined by Tc-99m RBC SPECT. Final diagnoses were based on findings of surgery, biopsy or follow-up by US for a minimum of 24 months after the scan.

RESULTS

In all, US detected 23 giant liver masses in 22 patients (3 men, 19 women). Eighteen GCHs were detected in 17 patients by Tc-99m RBC SPECT. Nine showed a homogeneously increased blood pool; 9 revealed peripheral high, but central low, uptake. The US patterns in these 18 GCHs were mixed-echoic in 12, hyperechoic in 4, and hypoechoic in 2. The other five large liver tumors, all proved by operation, had no increased uptake area with Tc-99m RBC SPECT. The US patterns of these were mixed-echoic in 3, hyperechoic in 1, and hypoechoic in 1.

CONCLUSIONS

Our study showed that there was no specific US pattern that would differentiate GCHs from other giant liver masses. Tc-99m RBC SPECT appeared to separate them clearly.

Biodistribution study of [(123)I] ADAM in mice: correlation with whole body autoradiography

Iodine-123 labeled 2-((2-((dimethylamino)methyl)phenyl)thio)-5-iodophenylamine ([(123)I] ADAM) has been suggested as a promising serotonin transporter (SERT) imaging agent. Much research has been accomplished, mainly focusing on the SERT binding sites in the central nervous system (CNS). However, the biodistribution of [(123)I] ADAM using whole body autoradiography (WBAR) has never been previously described, to the best of our knowledge. In this study, we assayed the biodistribution of [(123)I] ADAM in tissues/organs removed from mice, and measured their radioactivity with a scintillation counter (SC). The results showed that the liver has the highest uptake. On the other hand, the WBAR clearly demonstrated that [(123)I] ADAM was bound to SERT-rich sites including those in the brain stem, lung, adrenal glands and intestinal mucosa. This radiotracer also accumulated in the liver, kidney, and thyroid. The results from both methods were compared; each has its own complementary role in the biodistribution studies. The SC method revealed the total amount of radiotracer accumulation in each organ, and the WBAR demonstrated more anatomical details of the radiotracer's distribution. The whole body distribution results of the radioligand using both methods explore the usage of this novel radioligand for most possible SERT binding sites, not only in the CNS but also in the peripheral nervous system and neuroendocrine tissues. These findings suggest that [(123)I] ADAM is a potentially useful imaging agent for SERT.

Dopamine transporter concentration is reduced in asymptomatic Machado-Joseph disease gene carriers

Dopamine transporter (DAT) binding is decreased in Machado-Joseph disease (MJD) patients. To further investigate the DAT activity in asymptomatic MJD (aMJD) gene carriers, we performed this prospective study using (99m)Tc-TRODAT-1 ([(99m)Tc][2[[2-[[[3-(4-chlorophenyl)-8-methyl-8-azabicyclo[3,2,1]oct-2-yl]-methyl](2-mercaptoethyl)amino]ethyl]amino]ethane-thiolato(3-)-N2,N2',S2,S2]oxo-[1R-(exo-exo)])) brain SPECT on 5 aMJD gene carriers, 10 age-matched MJD patients, and 10 age-matched healthy control subjects.

METHODS

Brain SPECT images were acquired 4 h after intravenous injection of 925 MBq (25 mCi) (99m)Tc-T RODAT-1, which is known to bind specifically to the DAT on the nigrostriatal terminals. By fusing these SPECT images with a striatal atlas, obtained from MRI, binding of this tracer in the entire striatum was measured and the uptake values in bilateral striatal areas were compared between these 3 groups.

RESULTS

The uptake values of the aMJD gene carriers (P < 0.001) and MJD patients (P < 0.001) displayed a significant reduction compared with those of the control subjects. The reduction was more severe in the MJD patient group (P < 0.05). Bilateral putamen-to-caudate ratios were significantly lower in the aMJD gene carrier and MJD patient groups (P < 0.001). The dopamine neuronal activity, as represented by the tracer binding, was more prominently affected in the putamen in these patients and gene carriers.

CONCLUSION

(99m)Tc-TRODAT-1 brain SPECT is capable of detecting early alteration of dopamine neurons in the striatal region. Significantly, the results suggest that this impairment of presynaptic dopamine function actually occurs at an early stage, which was previously unrecognized in these aMJD gene carriers.

Prediction of bone fracture by bone mineral density in Taiwanese

BACKGROUND AND PURPOSE

This study evaluated whether lumbar spine bone mineral density (BMDL) and the rate of change of BMDL could predict the risk of bone fracture in Taiwanese.

METHODS

In 1989, a baseline survey was carried out in Lin-Kou Township. BMDL was measured using dual photon absorptiometry in 404 healthy volunteers. In 1994/95, a second survey was conducted to reexamine the BMDL and fracture history as well as the risk factors associated with fracture in these subjects. Fractures were classified according to the causes of the injury as severe or mild trauma.

RESULTS

Of the 404 original examinees, 381 (79%) participated in the second survey. Twenty-six subjects had experienced a total of 32 fracture incidents during their lifetime and 10 subjects had experienced fracture during the observation period. After adjusting for the effect of body mass index, gender, and age, each standard deviation of decrease in BMDL was found to be associated with a significant 2.38-fold increase in the risk of mild trauma fracture, and a BMDL below the fracture threshold was associated with a 3.93-fold increase of fracture risk. Higher BMDL change rates were found in subjects with a history of fracture.

CONCLUSION

This study indicates the importance of maintaining the BMDL above the fracture threshold (1 g/cm2). The strategy for fracture prevention should be directed at prevention of age-related bone loss.

99mTc-sulphur-colloid and heat-denatured 99mTc-labelled red cell scans demonstrating a giant intrapelvic spleen in a girl after splenectomy

A 17 x 12 x 5-cm giant intrapelvic mass in a 14-year-old girl is reported. This mass developed 6 years after a splenectomy for splenic torsion. The heat-denatured 99mTc-labelled red cell scan and 99mTc-sulphur-colloid scan confirmed the specific red cell sequestration function and reticuloendothelial activity in the giant intrapelvic spleen. The size and development of the giant intrapelvic spleen are unusual. The usefulness of functional images to diagnosis the nature of the intrapelvic mass is well demonstrated.

Breast uptake of iodine-131 mimicking lung metastases in a thyroid cancer patient with a pituitary tumour

We report a case of a 44-year-old female thyroid cancer patient with a pituitary tumour. 131I whole body scanning showed a change of chest uptake from a unilateral crescent uptake to a bilateral full breast uptake pattern. Hyperprolactinaemia and a pituitary tumour were diagnosed as a result of observing the 131I breast uptake.

Differential diagnosis of Parkinson's disease and vascular parkinsonism by (99m)Tc-TRODAT-1

The aim of this study was to use brain SPECT to differentiate vascular parkinsonism (VP) from Parkinson's disease.

METHODS

Fourteen VP patients (age range, 59-87 y; mean age, 70 +/- 7.5 y), 30 Parkinson's disease patients (age range, 54-84 y; mean age, 65 +/- 8.8 y), and 26 healthy (control) individuals (age range, 50-85 y; mean age, 60 +/- 9 y) were examined. A 925-MBq (25 mCi) dose of (99m)Tc-TRODAT-1 was injected intravenously, and brain SPECT images were acquired 4 h after injection. The ratio of specific to nonspecific striatal (99m)Tc-TRODAT-1 binding was measured and compared.

RESULTS

After a region-of-interest analysis of the images from VP patients, Parkinson's disease patients, and healthy volunteers was performed to obtain ratios of putamen to occipital and striatal to occipital binding as a measurement of specific binding to the dopamine transporters in these regions of the brain, where dopamine neurons are concentrated, the specific binding in the 14 VP patients was slightly lower than but not statistically different from that of the healthy individuals in both putamen and caudate areas. A significant decrease in uptake of (99m)Tc-TRODAT-1 in the striatum (P<0.01) was found in Parkinson's disease patients. Reduction of the uptake was more pronounced in the contralateral putamen of Parkinson's disease patients than that of VP patients (P<0.001). A significant bilateral striatal asymmetry was also observed in Parkinson's disease patients but not in VP patients (P< 0.01).

CONCLUSION

Our findings clearly show that, for VP patients, (99m)Tc-TRODAT-1 SPECT is a reliable method to differentiate VP from Parkinson's disease. Further studies, including those to differentiate Parkinson's disease from arteriosclerotic parkinsonism and patients with both VP and Parkinson's disease, are needed to help rule out the possibility of Parkinson's disease as early as possible.

Diagnosis and treatment of pyogenic psoas abscess in diabetic patients: usefulness of computed tomography and gallium-67 scanning

OBJECTIVES

To examine retrospectively the clinical presentations, microbiologic characteristics, and treatment outcomes of psoas abscess in patients with diabetes mellitus (DM) and to assess the usefulness of computed tomography and gallium-67 scanning in its early diagnosis.

METHODS

During a 9-year period, psoas abscesses in patients with DM were collected at a medical center. The clinical history and associated etiologic factors, microbiologic results, clinical outcomes, and hospitalization days were recorded. The use of imaging in the diagnosis of psoas abscess and other concomitant infectious lesions was also studied.

RESULTS

Fifteen patients with DM and psoas abscess (13 women and 2 men; mean age 58.7 +/- 9.0 years) were found. The most frequent symptom was fever (12 of 15). Of the six different microorganisms that grew in the blood and/or abscess cultures, Staphylococcus aureus was the most frequent (7 of 15). The most commonly associated pathologic finding was vertebral osteomyelitis (5 of 15). Computed tomography and/or magnetic resonance imaging confirmed the diagnosis of psoas abscesses in all 15 patients. The gallium-67 scan especially aided in the diagnosis of the patients who had initially been diagnosed as having fever of unknown origin (4 of 5) and in the diagnosis of concomitant lesions (9 of 12). Debridement or surgical drainage of the abscess was done in 12 patients. All the patients received adequate antibiotic treatment. However, the mortality rate was 20%. The average hospitalization stay was 42.7 +/- 20.7 days.

CONCLUSIONS

Psoas abscess in patients with DM is a disease with both diagnostic and therapeutic challenges. We found the infecting microorganisms to be variable and the mortality rate high.

The optimal imaging time for [99Tcm]TRODAT-1/SPET in normal subjects and patients with Parkinson's disease

Imaging of dopamine transporters (DATs) in the brain using [99Tcm]TRODAT-1 showed excellent pharmacokinetics for estimation of transporter concentrations. It has been reported that there may be differences in the binding kinetics of DAT radiotracers to DATs between normal subjects and patients with Parkinson's disease (PD). The aim of this study was to determine an optimal time point for (99Tcm]TRODAT-1 brain single photon emission tomography (SPET) acquisition that provides stable target to non-target ratios reflecting the DAT concentration in the brain. Serial [99Tcm]TRODAT-1 brain SPET images 2, 3 and 4 h after intravenous injection of [99Tcm]TRODAT-1 (925 MBq) were performed in five healthy subjects and nine PD patients. Regions of interests were drawn, and caudate/occipital (C/O) and putamen/occipital (P/O) specific to non-specific [99Tcm]TRODAT-1 binding ratios were calculated. The C/O and P/O ratios in healthy subjects showed consistent increases with time, but in PD patients, the C/O and P/O ratios of [99Tcm]TRODAT-1 reached a stable level at 3 h post-injection. There was a statistically significant difference (P < 0.001) between PD and normal subjects at 4 h post-injection for both the C/O and the P/O ratios. In conclusion, we recommend the acquisition of [99Tcm]TRODAT-1 SPET images at 4 h post-injection, as at this time point the C/O and P/O ratios can be used to discriminate between PD patients and healthy subjects.