[show abstract][hide abstract] ABSTRACT: We present a case of esophageal cancer underwent 18 F-fluorodeoxyglucose (FDG) positron emission tomog-raphy-computed tomography (PET-CT) on purpose of tumor surveillance. The patient is clinically asympto-matic. The FDG PET is negative for tumor recurrence. However, careful inspection of the CT and scout image revealed rupture of Port-A catheter with remote migra-tion-a potential lethal iatrogenic complication. Such probability must be kept in mind shall it be recognized and handled in time.
[show abstract][hide abstract] ABSTRACT: In positron emission tomography (PET) of the dopaminergic system, quantitative measurements of nigrostriatal dopamine function are useful for differential diagnosis. A subregional analysis of striatal uptake enables the diagnostic performance to be more powerful. However, the partial volume effect (PVE) induces an underestimation of the true radioactivity concentration in small structures. This work proposes a simple algorithm for subregional analysis of striatal uptake with partial volume correction (PVC) in dopaminergic PET imaging.
The PVC algorithm analyzes the separate striatal subregions and takes into account the PVE based on the recovery coefficient (RC). The RC is defined as the ratio of the PVE-uncorrected to PVE-corrected radioactivity concentration, and is derived from a combination of the traditional volume of interest (VOI) analysis and the large VOI technique. The clinical studies, comprising 11 patients with Parkinson's disease (PD) and 6 healthy subjects, were used to assess the impact of PVC on the quantitative measurements. Simulations on a numerical phantom that mimicked realistic healthy and neurodegenerative situations were used to evaluate the performance of the proposed PVC algorithm. In both the clinical and the simulation studies, the striatal-to-occipital ratio (SOR) values for the entire striatum and its subregions were calculated with and without PVC.
In the clinical studies, the SOR values in each structure (caudate, anterior putamen, posterior putamen, putamen, and striatum) were significantly higher by using PVC in contrast to those without. Among the PD patients, the SOR values in each structure and quantitative disease severity ratings were shown to be significantly related only when PVC was used. For the simulation studies, the average absolute percentage error of the SOR estimates before and after PVC were 22.74 % and 1.54 % in the healthy situation, respectively; those in the neurodegenerative situation were 20.69 % and 2.51 %, respectively.
We successfully implemented a simple algorithm for subregional analysis of striatal uptake with PVC in dopaminergic PET imaging. The PVC algorithm provides an accurate measure of the SOR in the entire striatum and its subregions, and improves the correlation between the SOR values and the clinical disease severity of PD patients.
Annals of Nuclear Medicine 10/2013; · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: 6-[(18)F]Fluoro-L: -DOPA (FDOPA) is a radiopharmaceutical valuable for assessing the presynaptic dopaminergic function when used with positron emission tomography (PET). More specifically, the striatal-to-occipital ratio (SOR) of FDOPA uptake images has been extensively used as a quantitative parameter in these PET studies. Our aim was to develop an easy, automated method capable of performing objective analysis of SOR in FDOPA PET images of Parkinson's disease (PD) patients.
Brain images from FDOPA PET studies of 21 patients with PD and 6 healthy subjects were included in our automated striatal analyses. Images of each individual were spatially normalized into an FDOPA template. Subsequently, the image slice with the highest level of basal ganglia activity was chosen among the series of normalized images. Also, the immediate preceding and following slices of the chosen image were then selected. Finally, the summation of these three images was used to quantify and calculate the SOR values. The results obtained by automated analysis were compared with manual analysis by a trained and experienced image processing technologist.
The SOR values obtained from the automated analysis had a good agreement and high correlation with manual analysis. The differences in caudate, putamen, and striatum were -0.023, -0.029, and -0.025, respectively; correlation coefficients 0.961, 0.957, and 0.972, respectively.
We have successfully developed a method for automated striatal uptake analysis of FDOPA PET images. There was no significant difference between the SOR values obtained from this method and using manual analysis. Yet it is an unbiased time-saving and cost-effective program and easy to implement on a personal computer.
Annals of Nuclear Medicine 09/2011; 25(10):796-803. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to investigate the associations among central obesity, inflammation, and left ventricular (LV) diastolic dysfunction by structural equation modeling. Echocardiographic parameters were assessed in 102 otherwise-healthy adults over age 30. The participants were classified as having LV diastolic dysfunction by echocardiographic findings including mitral inflow E/A ratio <1, deceleration time >220 cm/s, or decreased peak annular early diastolic velocity in tissue Doppler imaging or otherwise the control group. Serum C-reactive protein (CRP) and lipid profile were also measured. The homeostasis model of insulin resistance (HOMA) was calculated. Central obesity was assessed by computerized tomography (CT) at the L4 level. In a multivariate regression analysis, the relationship between visceral adipose tissue (VAT) and LV diastolic dysfunction became insignificant when CRP was introduced into the model, although CRP itself was significantly associated with LV diastolic dysfunction (odds ratio (OR): 1.32, 95% confidence interval (CI): 1.01-1.72, P = 0.04). A significant correlation was also found between VAT and CRP (r = 0.70; P < 0.001). We then performed path analysis as illustrated by the structural equation model. This proved our hypotheses that VAT might affect LV diastolic dysfunction through the effect of CRP (total fat load with inflammation (B = 1.133, P < 0.001) and that inflammation might affect LV diastolic dysfunction (B = 0.373. P < 0.001)). Using structural equation modeling, we concluded that higher amounts of VAT were associated with low-grade inflammation and this may lead to subclinical LV diastolic dysfunction in otherwise-healthy subjects.
[show abstract][hide abstract] ABSTRACT: A 62-year-old man with locally advanced squamous cell carcinoma of the right retromolar trigone, pT4bN0M0, had surgery and postoperative concurrent chemoradiation therapy for 4 months. Right otalgia developed and facial magnetic resonance imaging revealed lesions which corresponded to postirradiation inflammation. F-18 FDG PET/CT showed recurrent lesions in the right buccal region and along the route of the mandibular division of the trigeminal nerve. This report indicates that F-18 FDG PET/CT could detect occult perineural tumor spread before identification on MRI especially in postoperative and postirradiation patients and effect intensity-modulated radiation therapy planning.
Clinical nuclear medicine 03/2010; 35(3):189-91. · 3.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: A 42-year-old woman with advanced alcoholic liver cirrhosis was referred for a Tc-99m-labeled red blood cell (RBC) abdominal scan due to tarry stool passage. The Tc-99m RBC scan revealed a tangled linear radioactivity accumulation, extending from the right epigastric area to the right lower pelvic region. The integrated single-photon emission computed tomography/computed tomography (SPECT/CT) with 3D volume rendering imaging and CT bone segmentation display confirmed the portosystemic collateral circulation.
Clinical nuclear medicine 12/2009; 34(12):958-9. · 3.92 Impact Factor
[show abstract][hide abstract] ABSTRACT: To differentiate between benign and malignant lesions of the lung, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has limitations such as a lower specificity in cases of non-specific inflammation. The positive predictive value is unsatisfactory in countries where inflammatory lung disorders are prevalent. We present the preliminary results of the usefulness of combining 11C-methionine-PET and 18F-FDG-PET in this context.
Fifteen patients with indeterminate solitary pulmonary nodules/masses (10 men, 5 women; average age 64.7 +/- 14.0 years, ranging from 25 to 87 years) were studied using 11C-methionine- and 18F-FDG-PET. Interpretations were primarily made on visual analysis with five-point scale and a consensus of two nuclear medicine physicians, using standardized uptake value as an accessory reference. Foci of abnormal radiotracer uptake were subsequently correlated with clinical follow-up, imaging modalities such as chest radiography, chest computed tomography (CT), serial PET studies, and pathology results from bronchoscopic biopsy and/or surgical specimen.
Diagnoses were established in 14 patients. The 11C-methionine-PET and 18F-FDG-PET studies were both true positive in two cases of adenocarcinoma and true negative in two cases of clinical benign nodules. In one case of lymphoid hyperplasia both 11C-methionine-PET and 18F-FDG-PET showed false-positive findings. Discordant results were obtained in nine cases. In spite of the false-positive results of 18F-FDG-PET, 11C-methionine-PET was true negative in four cases with chronic inflammatory nodules and three cases of pulmonary tuberculosis. Furthermore, (11)C-methionine-PET was true positive in one case of lung metastasis of thyroid cancer, and in another with recurrence of gastric cancer, respectively, for which 18F-FDG-PET imaging was false negative.
Our experience indicates that 11C-methionine-PET seems more specific and sensitive when compared with 18F-FDG-PET for the purpose of differentiating benign and malignant thoracic nodules/masses. The possibility of an FDG-avid lesion being malignant is decreased if it shows a negative result by 11C-methionine-PET.
Annals of Nuclear Medicine 08/2008; 22(6):533-8. · 1.41 Impact Factor
[show abstract][hide abstract] ABSTRACT: Interictal brain 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is useful for localizing the focus of a seizure, and thalamic hypometabolism has been observed in temporal lobe epilepsy (TLE). In this study, we aimed to investigate the prevalence of thalamic hypometabolism and to assess the usefulness of this supplementary finding for lateralizing epileptic foci on FDGPET scans in patients with TLE.
This was a retrospective study of 47 patients who underwent anterior temporal lobectomy to treat medically intractable TLE. Other inclusion criteria were age older than 18 years, preoperative interictal FDG-PET, no structural abnormality (except for mesial temporal sclerosis) on preoperative magnetic resonance imaging, and seizure-free status (Engel class I) for at least 2 years after the operation. The presence and location of hypometabolism on FDG-PET scans were recorded.
Of the 47 patients examined, 12 were subsequently excluded. Concomitant hypometabolism in both the temporal lobe and the ipsilateral thalamus was observed on FDG-PET scans in seven (20%) of the remaining 35 patients. One patient had thalamic hypometabolism contralateral to the hypometabolic temporal lobe.
Ipsilateral thalamic hypometabolism is a supplementary finding on FDG-PET scans in patients with TLE and can aid in lateralizing epileptic foci during FDG-PET. However, in rare cases, hypometabolism of the contralateral thalamus can occur and cause false lateralization.
Journal of the Formosan Medical Association 07/2008; 107(7):567-71. · 1.00 Impact Factor
[show abstract][hide abstract] ABSTRACT: Case series.
Evaluation of new vertebroplasty technique.
Viscous polymethylmethacrylate cement is frequently used to avoid leakage in vertebroplasty. However, the large force required to inject the cement can require the use of special equipment or the direct injection of the cement without a cannula. In addition, injection under fluoroscopic guidance with a short or absent cannula is associated with a higher intraoperative radiation dose. A method using an angiographic catheter for thin cement injection is presented.
Real-time, fluoroscopy-controlled, catheter-assisted, thin cement injection was used for 102 vertebroplasty sessions (84 patients, 148 vertebrae). Leakage was monitored in 85 procedures via computed tomography.
All vertebral bodies were successfully and satisfactorily filled with bone cement. Cement leakage was evident in 50% of the 85 asymptomatic cases (25 paraspinal, 29 epidural, and 30 intradisc space). On follow-up, new compression fractures were noted in the same (n = 5) or adjacent (n = 16) vertebral body, and elsewhere (n = 10). Vertebroplasty provided pain relief in >90% of cases. Recurrent compression fracture occurred in 5 vertebrae of 4 patients after vertebroplasty. New compression fractures occurred in 16 adjacent vertebral bodies of 11 patients and in 10 vertebral bodies remote from the site. One patient who developed osteomyelitis was successfully treated with antibiotics alone.
Real-time, fluoroscopy-controlled, catheter-assisted, low-viscosity cement injection is a safe and feasible method for vertebroplasty, and produces a comparable outcome as high-viscosity cements.
[show abstract][hide abstract] ABSTRACT: Thoracic location of an aberrant kidney is the least encountered renal malposition. We present a 62-year-old female patient with ovarian malignant mixed epithelial tumor complicated with massive ascites and right hemidiaphragmatic eventration. The cephalad malpositioned right kidney was found incidentally as an intrathoracic mass on Tc-99m MDP bone scintigraphy.
[show abstract][hide abstract] ABSTRACT: The purpose of this study was to assess the use of 1-(11)C-acetate (ACE) as a metabolic tracer for the detection and characterisation of astrocytomas.
Positron emission tomography (PET) studies with ACE and 2-(18)F-fluoro-2-deoxy-D-glucose (FDG) were performed sequentially in 26 patients with primary astrocytomas. Images were analysed by visual interpretation and determination of the tumour to cortex ratio (T/C ratio) and standardised uptake value (SUV). The tumour uptake was visually scored into three grades as compared with the contralateral cortex: clearly lower (-), almost equal (+) and clearly higher (++).
There were 85% of astrocytomas with ++ ACE uptake, 15% with + ACE uptake and none with - ACE uptake. Only 19% of astrocytomas had ++ FDG uptake. Thirty-seven percent of high-grade astrocytomas had + FDG uptake and 37% had - FDG uptake. The sensitivity and specificity of the FDG T/C ratio in discriminating high-grade from low-grade astrocytomas were 79% and 100%, respectively, at the cutoff value of 0.75. Using 2.33 as the cutoff value of the ACE T/C ratio, the sensitivity and specificity were 42% and 86%, respectively. FDG was better than ACE in discriminating high-grade from low-grade astrocytomas. T/C ratios and SUVs of FDG uptake of tumours correlated with the histological grades, but those of ACE uptake did not.
ACE appears to be a promising tracer for use in the detection of primary astrocytomas, but is of limited value in the differentiation of high- and low-grade astrocytomas. ACE is complementary to FDG for the diagnosis and characterisation of astrocytoma.
European journal of nuclear medicine and molecular imaging 05/2006; 33(4):420-7. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Subacute sclerosing panencephalitis (SSPE), originally described by Dawson in 1933, is today recognized as a progressive neurodegenerative disease caused by latent infection with mutated measles virus. Its threat is higher in underdeveloped nations and is expected to increase in the United States because of the measles epidemic in 1988-1990. Concomitant F-18 FDG PET and F-18 FDOPA PET brain images in SSPE appear to be unusual.
Clinical Nuclear Medicine 08/2005; 30(7):519-20. · 2.96 Impact Factor
[show abstract][hide abstract] ABSTRACT: A 74-year-old man underwent low anterior resection for rectal cancer. Technetium-99m methylene diphosphonate (MDP) bone scanning was performed as part of the patient's postoperative follow-up study. Scans revealed an area of increased tracer uptake in the left hemipelvis. Coronal single-photon emission computed tomography and caudal images clearly separated the lesion from the skeletal structures. Transverse magnetic resonance images showed a large diverticulum originating from the left lateral wall of the bladder. The pelvic findings on the bone scan were the result of tracer retained within this diverticulum.
Clinical Nuclear Medicine 05/2005; 30(4):276-7. · 2.96 Impact Factor