Longitudinal evaluation using FP-CIT in patients with parkinsonism.

OBJECTIVE: To assess a group of patients with parkinsonism using serial studies with FP-CIT, basically the initial false negative results. METHODS: Restrospective study of 92 patients (55 men and 37 women) who had undergone 2 different FP-CIT studies because of discrepancies between study results and clinical progression. The mean elapsed time between the studies was 26 months (SD: 6). We performed a semi-quantitative study using the patient's clinical history and the available literature to analyse discrepant cases with a normal initial study and subsequent pathological findings. RESULTS: A total of 184 studies were completed for 92 patients; 11 of those 92 showed discrepancies between initial and subsequent studies. Among the 11 discrepant cases, 7 showed a normal initial study and pathological findings at a later date. Analysis of the predominant clinical features that might explain this behaviour revealed that 4 of these 7 subjects presented tremor-dominant parkinsonism. Regarding the rest, 1 presented early stage parkinsonism and was treated with antidopaminergic agents; 1 was classified as probable multisystem atrophy type C, and the third showed clinical signs of atypical parkinsonism without any causes of those signs being identified. CONCLUSIONS: Serial FP-CIT studies are unnecessary in the large majority of cases, but they may be justifiable in certain clinical situations.

Improved parkinsonism diagnosis using a partial least squares based approach.

PURPOSE: An accurate and early diagnosis of Parkinsonian syndrome (PS) is nowadays a challenge. This syndrome includes several pathologies with similar symptoms (Parkinson's disease, multisystem atrophy, progressive supranuclear palsy, corticobasal degeneration and others) which make the diagnosis more difficult. (123)I-ioflupane allows to obtain in vivo images of the brain that can be used to assist the PS diagnosis and provides a way to improve its accuracy. METHODS: In this paper, we show a novel method to automatically classify (123)I-ioflupane images into two groups: controls or PS. The proposed methodology analyzes separately each hemisphere of the brain by means of a novel approach based on partial least squares (PLS) and support vector machine. RESULTS: A database with 189 (123)I-ioflupane images (94 controls and 95 pathological images) was used for evaluation purposes. The application of the proposed method based on PLS yields high accuracy rates up to 94.7% with sensitivity = 93.7% and specificity = 95.7%, outperforming previous approaches based on singular value decomposition, which are used as a reference. CONCLUSIONS: The use of advanced techniques based on classical signal analysis and their application to each hemisphere of the brain separately improves the (assisted) diagnosis of PS.

Automatic assistance to Parkinson's disease diagnosis in DaTSCAN SPECT imaging.

PURPOSE: In this work, an approach to computer aided diagnosis (CAD) system is proposed as a decision-making aid in Parkinsonian syndrome (PS) detection. This tool, intended for physicians, entails fully automatic preprocessing, normalization, and classification procedures for brain single-photon emission computed tomography images. METHODS: Ioflupane[(123)I]FP-CIT images are used to provide in vivo information of the dopamine transporter density. These images are preprocessed using an automated template-based registration followed by two proposed approaches for intensity normalization. A support vector machine (SVM) is used and compared to other statistical classifiers in order to achieve an effective diagnosis using whole brain images in combination with voxel selection masks. RESULTS: The CAD system is evaluated using a database consisting of 208 DaTSCAN images (100 controls, 108 PS). SVM-based classification is the most efficient choice when masked brain images are used. The generalization performance is estimated to be 89.02 (90.41-87.62)% sensitivity and 93.21 (92.24-94.18)% specificity. The area under the curve can take values of 0.9681 (0.9641-0.9722) when the image intensity is normalized to a maximum value, as derived from the receiver operating characteristics curves. CONCLUSIONS: The present analysis allows to evaluate the impact of the design elements for the development of a CAD-system when all the information encoded in the scans is considered. In this way, the proposed CAD-system shows interesting properties for clinical use, such as being fast, automatic, and robust.

[Quantitative evaluation of SPECT with FP-CIT. Importance of the reference area]. / Valoración cuantitativa del SPECT con FP-CIT. Importancia del área de referencia.

OBJECTIVE: The aim of this study is to compare several uptake indexes between specific and non-specific activity to determine the existence of degenerative Parkinsonism according to different reference areas. MATERIAL AND METHODS: A total of 46 patients (23 men and 23 women), randomly selected from individuals referred to our center with a movement disorder, were included in the study. Mean age was 70.2 ± 10.2 years (41-87). The uptake indexes were obtained through the areas of interest (ROIs) located in the striate (specific uptake) and other reference ROIs located in areas with different concentrations of serotonin receptors: low-cerebellum, medium-occipital cortex and high-midbrain. RESULTS: A high linear correlation was found between indexes having low and medium concentration of serotonin receptors. The ROC curve analysis shows an area under the curve of 0.874, 0.886 and 0.739 and regression coefficients of 5.41, 6.62 and 3.41, respectively for the striatum/cerebellum (E/C), striatum/occipital (E/O) and striatum midbrain (E/M) indexes. Optimal cutoff for E/O (1.35), index with the best behavior, provides a sensitivity of 0.84 and specificity of 0.89. CONCLUSION: The reference area selected may alter the predictive power of the different indexes to determine the existence of a degenerative Parkinsonism.

Usefulness of 18F-Choline Positron Emission Tomography - Computed Tomography in the therapeutic management of patients with biochemical recurrence of prostate adenocarcinoma treated with brachytherapy. / Utilidad de la tomografía de emisión de positrones / tomografía computarizada con 18F-colina en el manejo terapéutico de pacientes con recidiva bioquímica de adenocarcinoma de próstata tratados con braquiterapia.

OBJECTIVE: The objective of the study was to evaluate the usefulness of 18F-choline PET/CT in biochemically recurrent prostate cancer patients treated with brachytherapy, as well as to assess the changes in therapeutic management derived from its outcome. MATERIAL AND METHODS: Retrospective study of 20 patients between 51 and 78 years old, with a history of prostate adenocarcinoma that had been treated with brachytherapy and presented biochemical recurrence (PSA 3.1-12 ng/ml) and staging tests (CT and bone scan) without alterations, were included. The findings visualized in the PET/CT scan with 18F-choline were correlated with the histopathology and/or the evolution of the PSA after therapy. RESULTS: 18F-choline PET/CT scan only detected local recurrence in 15 patients. Local and regional recurrences were seen in 4 patients, and 1 patient presented local and bone recurrence. Local recurrence detected in PET was confirmed by anatomopathological studies in 85% of the cases. In one patient, these findings (PET scan) turned out to be prostatitis, and it could not be confirmed in another patient. Of the cases with local and regional recurrence, local recurrence was histologically confirmed in 3 out of 4 patients. 18F-choline PET/CT changed the therapeutic management in 25% of the patients, discarding the initially planned salvage surgery in 3 cases, 1 radiotherapy and 1 brachytherapy. CONCLUSION: 18F-choline PET/CT could be a useful technique in the group of patients with biochemical recurrence after brachytherapy, providing locoregional and distant involvement findings which had not been detected with conventional imaging tests, thus determining a more adequate therapeutic management.

Improved uniformity in tomographic myocardial perfusion imaging with attenuation correction and enhanced acquisition and processing.

UNLABELLED: Tissue attenuation results in nonuniform myocardial perfusion images with significant sex differences. New SPECT imaging protocols to correct attenuation are currently under investigation. This study was performed to assess the effects of attenuation correction (AC) on overall image uniformity compared with more conventional imaging protocols in both men and women. METHODS: Thirty-nine patients (19 men, 20 women) with less than a 5% likelihood of coronary artery disease were studied. (99m)Tc-sestamibi studies were acquired with a triple-head scanner equipped with a simultaneous transmission and emission protocol. Four imaging protocols were compared: a 180 degrees acquisition and filtered backprojection reconstruction (FBP), a 360 degrees acquisition and FBP, a 360 degrees acquisition and iterative reconstruction (IT), and a 360 degrees acquisition with IT and AC. Quantitative analysis was performed to evaluate myocardial tracer uniformity for men and women. RESULTS: 180 degrees, 360 degrees FBP, and 360 degrees IT showed sex differences, with decreased tracer concentration in the anterior wall in women and decreased tracer concentration in the inferior wall in men. AC images showed the greatest uniformity (9.9% coefficient of variation for AC versus 12.5% for IT, P < 0.0001), and no statistically significant differences in uniformity were seen between male and female AC studies. CONCLUSION: More uniform myocardial perfusion images were obtained with AC, resulting in images with no differences in uniformity between men and women. These techniques are expected to improve specificity and overall diagnostic accuracy.

[Impact of the correction of the attenuation in myocardial perfusion image with SPECT]. / Impacto de la corrección de atenuación en la imagen de perfusión miocárdica con SPET.

BACKGROUND: The aim of this study was to assess the effect of attenuation correction on gender differences in normals and to evaluate its effect on the size and severity of lateral wall perfusion defects in patients with circumflex artery disease. MATERIAL AND METHODS: Tomographic myocardial perfusion imaging with and without attenuation correction was performed on 32 patients with circumflex artery stenosis and compared with patients with less than 5% likelihood of coronary disease. Images were acquired with a triple headed scanner and reconstructed using an iterative algorithm and re-sliced in the short axis plane. Regional count densities were measured on selected short axis slices from the base to the apex in both patients and normals. RESULTS: All attenuation corrected images were found to be more uniform than the non attenuation corrected images on the patients with less than 5% likelihood of coronary artery disease. The coefficient of variation was 12.5% for non attenuation corrected images versus 9.9% for attenuation corrected images (p < 0.0001). When female and male segmental count distributions were compared, significant differences were found which were resolved after attenuation correction. In patients with circumflex artery stenosis, the anterolateral and lateral count densities were lower at all levels with attenuation corrected images with an increasing difference from base to apex. CONCLUSIONS: The use of attenuation correction results in a greater uniformity in normals and an improved estimation of extent and severity of perfusion defects in the territory of the circumflex artery.

[Lung scintigraphy with technetium 99m depreotide in the assessment of solitary pulmonary nodules]. / La gammagrafía con 99mTc-depreótida en la valoración del nódulo pulmonar solitario.

A solitary pulmonary nodule (SPN) is defined as a parenchymal lesion measuring less than 3 cm in diameter that is not associated with other lesions. Ninety percent of SPNs are discovered incidentally and most are benign. The management of radiographically indeterminate SPNs has not been established and invasive procedures must be undertaken in order to understand the nature of the nodule. We review our experience with the use of somatostatin receptor scintigraphy with technetium Tc99m depreotide in 10 patients with suspected malignant SPN. We discuss the limitations and applications of this technique in the evaluation of whether SPNs are benign or malignant for the purpose of identifying patients for biopsy. For this application, this technique can be considered an alternative to positron emission tomography using fluorine-18 fluordeoxyglucose.

[Diagnosis and localization of hyperparathyroidism by nuclear medicine procedures]. / Contribución de las técnicas de medicina nuclear al diagnóstico y localización del hiperparatiroidismo.

Primary hyperparathryoidism is a PTH hypersecretion caused by the parathyroid glands. In most cases (85%), the origin is to be due to the existence of a parathyroid adenoma, despite the intrinsic difficulty in being localized under certain circumstances. From some time now, we can count with the invaluable help of a nuclear medicine technique, namely the parathyroid scintigraphy with Technetium 99m-sestamibi (Tc99m-MIBI), a technique which is easy to perform, cheap and with excellent results, and which additionally can provide us with the above mentioned necessary information regarding location. We present here the case of a patient suffering from primary hyperparatyiroidism, in whom both the disease and the precise location of the hyperfunctioning tissue were identified by means of the parathyroid scintigraphy. Another nuclear medicine procedure, the one known as bone scintigraphy, also contributed meaningfully to the correct diagnosis in the same patient.

[123 I-MIBG myocardial sympathetic innervation scintigraphy and Parkinson's disease. Preliminary results]. / Gammagrafía miocárdica de inervación con 123 I-MIBG y enfermedad de Parkinson. Resultados preliminares.

OBJECTIVES: Cardiac sympathetic function in patients with Parkinson's disease (PD) is significantly impaired. Cardiac scintigraphy with 123I-metaiodobenzylguanidine (123I-MIBG) is used to assess cardiac sympathetic function. METHODS: A total of 29 consecutive patients with PD and 10 control subjects without neurological disease were studied. Myocardial imaging with 123I-MIBG was performed to evaluate cardiac sympathetic function. Early and delayed images of the anterior view were obtained at 15 min. and 4 h. after injection of 123I-MIBG, respectively. 123I-MIBG uptake was quantified qualitatively and semiquantitatively by calculating a heart-to-mediastinum (H/M) ratio. RESULTS: The heart/mediastinum ratio was markedly reduced in patients with PD (I to IV on the Hoehn and Yahr scale) when compared to the control subjects (p < 0.05). This finding was independent of the length and severity of the disease or the pharmacological treatment of the patients. None of the control subjects showed decrease in myocardial 123I-MIBG uptake. CONCLUSIONS: Our findings indicate that a decrease in myocardial accumulation of 123I-MIBG was observed in the early stages of PD. This suggests that the measurement of 123I-MIBG may help the early diagnosis of PD, and can be used to detect cardiac autonomic dysfunction, especially in patients without typical signs and symptoms.

[Functional neuroimaging in the diagnosis of patients with Parkinsonism: Update and recommendations for clinical use]. / Neuroimagen funcional en el diagnóstico de pacientes con síndrome parkinsoniano: actualización y recomendaciones para el uso clínico.

Functional Neuroimaging has been traditionally used in research for patients with different Parkinsonian syndromes. However, the emergence of commercial radiotracers together with the availability of single photon emission computed tomography (SPECT) and, more recently, positron emission tomography (PET) have made them available for clinical practice. Particularly, the development of clinical evidence achieved by functional neuroimaging techniques over the past two decades have motivated a progressive inclusion of several biomarkers in the clinical diagnostic criteria for neurodegenerative diseases that occur with Parkinsonism. However, the wide range of radiotracers designed to assess the involvement of different pathways in the neurodegenerative process underlying Parkinsonian syndromes (dopaminergic nigrostriatal pathway integrity, basal ganglia and cortical neuronal activity, myocardial sympathetic innervation), and the different neuroimaging techniques currently available (scintigraphy, SPECT and PET), have generated some controversy concerning the best neuroimaging test that should be indicated for the differential diagnosis of Parkinsonism. In this article, a panel of nuclear medicine and neurology experts has evaluated the functional neuroimaging techniques emphazising practical considerations related to the diagnosis of patients with uncertain origin parkinsonism and the assessment Parkinson's disease progression.

[Early alterations of adrenergic cardiac function in Parkinson's disease]. / Alteración precoz de la función adrenérgica cardíaca en la enfermedad de Parkinson.

INTRODUCTION: Myocardial sympathetic (adrenergic) function is significantly affected in patients with idiopathic Parkinson's disease (PD) as is deduced from the cardiac scintigraphy evaluation with 123I-metaiodobenzylguanidine (123I-MIBG). PATIENTS AND METHODS: In the present study, 60 patients with PD were studied compared to 17 normal subject without neurological disease. The clinical parameters evaluated were severity of the condition (measured by Hoehn and Yahr Scale), vegetative manifestations, development time and use and type of medication taken. Myocardial adrenergic function was analyzed by imaging with 123I-MIBG. Early (15 min) and delayed (4 h) images of the anterior view were obtained after injection of 123I-MIBG. Qualitative and semiquantitative 123I-MIBG uptake was quantified by calculating a heart-to-mediastinum (H/M) ratio. RESULTS: We found a significant decrease of H/M ratio in patients with PD as compared with controls (p < 0.01) independently of development time, severity of the condition, use of medication or vegetative manifestations. CONCLUSIONS: There is an important noradrenergic alteration in PD, that can be detected from early stages and does not exist in other parkinsonisms caused by a different pathogenic mechanism.

Gammagrafía miocárdica de inervación con 123I-MIBG y enfermedad de Parkinson. Resultados preliminares / 123I-MIBG myocardial sympathetic innervation scintigraphy and parkinson's disease. Preliminary results

Objetivos: La función simpática miocárdica se encuentra significativamente afectada en los pacientes con enfermedad de Parkinson idiopática (EP). La gammagrafía miocárdica con 123I-metayodobencilguanidina (123I-MIBG) permite la evaluación de la función simpática cardíaca. Material y métodos: Se estudiaron 29 pacientes consecutivos de EP en diferentes estadíos de la enfermedad, y 10 sujetos controles sin enfermedad neurológica. Se estudió la función miocárdica mediante gammagrafía con 123I-MIBG.Se adquirieron mediante técnica planar imágenes de tórax anterior, de forma precoz a los 15 minutos postadministración del trazador, y tardía a las 4 horas. La captación miocárdica se valoró de manera cualitativa y semicuantitativa mediante la obtención de índices corazón/mediastino (ICM). Resultados: Los ICM mostraron una marcada reducción en los pacientes de EP (I a IV en la escala de Hoehn-Yahr), en comparación con los sujetos controles (p < 0,05), independiente del tiempo de evolución de la enfermedad, de la severidad, y del tratamiento farmacológico empleado Ninguno de los sujetos controles mostró reducción de la captación miocárdica de 123I-MIBG. Conclusiones: Nuestros hallazgos indican que en la EP existe reducción en la captación miocárdica de 123I-MIBG, pudiendo apreciarse desde estadíos precoces de la enfermedad. La utilización de la gammagrafía con 123I-MIBG puede ayudar en el diagnóstico precoz de la EP, y detectar alteración autonómica cardíaca, particularmente en pacientes presintomáticos con esta patología. (AU)