Ictus lacunar como complicación muy tardía de la radioterapia: valor de las técnicas de medicina nuclear / Lacunar stroke as a very late complication of radiotherapy: value of nuclear medicine techniques

INTRODUCCIÓN: La radioterapia es un tratamiento de gran utilidad en las neoplasias del sistema nervioso central. El rango temporal de sus complicaciones es muy amplio, ya que aparecen incluso muchos años más tarde de haberla finalizado. Estas complicaciones tardías se comportan clínica y radiológicamente de forma similar a una recidiva; un estudio funcional diagnóstico con isótopos radiactivos puede ayudar a tomar una decisión terapéutica. CASO CLÍNICO: Varón que presentó de forma brusca sintomatología neurológica deficitaria en la misma localización donde 25 años antes había recibido radioterapia por un astrocitoma pilocítico. La resonancia magnética sugería un ictus lacunar, pero un hallazgo en la secuencia de perfusión obligaba a ser más preciso en el diagnóstico. Una tomografía por emisión de positrones-tomografía computarizada (PET-TC) con C11-metionina mostró un aumento de captación compatible con neoplasia. La evolución espontánea regresiva de los síntomas inclinó a tomar una actitud conservadora. Una resonancia magnética realizada tres meses más tarde confirmó el ictus lacunar. CONCLUSIONES: La reaparición de síntomas neurológicos años más tarde de la radioterapia de una neoplasia cerebral supone un dilema diagnóstico. Las técnicas diagnósticas actuales son muy precisas, pero presentan falsos positivos. Las distintas técnicas de medicina nuclear, en concreto la PET-TC con C11-metionina, suponen una ayuda diagnóstica. Con este caso se pretende llamar la atención sobre una de las complicaciones tardías de la radioterapia y los distintos diagnósticos diferenciales. Los avances diagnósticos y terapéuticos han aumentado la esperanza de vida de los pacientes oncológicos, con lo que estas complicaciones tardías se prevén más frecuentes

INTRODUCTION: Radiation therapy is a very useful treatment for central nervous systems neoplasms. The time range of its complications is very wide; they appear even many years after its completion. These late complications behave clinically and radiologically similar to a relapse; a functional diagnostic study with radioactive isotopes can help to make a therapeutic decision. CASE REPORT: A male suddenly presented deficient neurological symptoms in the same site where he received radiation therapy 25 years earlier for a pilocytic astrocytoma. The MRI findings suggested a lacunar stroke but a finding in the perfusion sequence forced us to be more precise in the diagnosis. A PET-CT 11C-methionine was performed which showed an increased uptake compatible with neoplasia. The spontaneous regressive evolution of the symptoms inclined us to take a conservative attitude. Lacunar ictus was confirmed on MRI three months later. CONCLUSIONS: The reappearance of neurological symptoms years after radiotherapy of a brain neoplasm poses a diagnostic dilemma. Current diagnostic techniques are very accurate but present false positives. The various nuclear medicine techniques, in particular PET-CT 11C-methionine, are a diagnostic aid. With the presentation of this case we intend to draw attention to one of the late complications of radiation therapy and the various differential diagnoses. Diagnostic and therapeutic advances have increased the life expectancy of cancer patients, so these late complications are expected to be more frequent

A 5-year longitudinal evaluation in patients with mild cognitive impairment by 11C-PIB PET/CT: a visual analysis.

OBJECTIVE: The aim of this study was to evaluate the cerebral amyloid distribution in patients with mild cognitive impairment (MCI), assessed by carbon-11-Pittsburgh compound B (C-PIB) PET/CT, after 5 years of follow-up. PATIENTS AND METHODS: Ten amnestic MCI (A-MCI) and four nonamnestic (NA-MCI) patients were studied by C-PIB PET/CT and re-evaluated 5 years later by a new C-PIB PET/CT. PET/CT scans were acquired 60-90 min after the administration of 555 MBq C-PIB and analyzed visually, to obtain a score of the cerebral cortical C-PIB retention in the frontal, basal ganglia (BG), temporoparietal (TP), occipital, posterior cingulate, and cerebellum areas. Initial and 5-year follow-up C-PIB retentions were compared. RESULTS: Initially, 9/10 A-MCI patients were C-PIB positive and one was C-PIB negative. All four NA-MCI patients were C-PIB negative. Of the C-PIB-positive A-MCI patients, seven progressed to Alzheimer's disease dementia (AD-D), one to mixed dementia and one remained as A-MCI. The C-PIB-negative A-MCI patient remained as A-MCI. Of the four C-PIB-negative NA-MCI, one progressed to semantic dementia. All changes in C-PIB retention were of low intensity. The A-MCI patients who progressed to AD-D (n=7) showed an increase in C-PIB retention in the frontal (5/7), BG (3/7), TP (3/7), occipital (1/7), and posterior cingulate (1/7) regions. The A-MCI patient who progressed to mix dementia showed an increase in C-PIB retention in the frontal region. The C-PIB-positive A-MCI patient who remained as A-MCI showed an increase in C-PIB retention in the frontal, BG, and TP areas. The amyloid deposition in the anterior part of the brain (frontal, TP, and BG) increased more than that in the posterior part (occipital and precuneus) (7/9 vs. 2/9; P<0.05). CONCLUSION: PIB retention increased predominantly in the frontal, BG, and TP areas. C-PIB-positive A-MCI patients mostly progressed to AD-D, showing similar topographic changes in their cerebral C-PIB pattern than the patient who remained as A-MCI.

Usefulness of 18F-FDG-PET/CT imaging in a patient with neurosarcoidosis / Utilidad de la 18F-FDG-PET/CT en un paciente con neurosarcoidosis

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Diagnostic role of 11C-Pittsburgh compound B retention patterns and glucose metabolism by fluorine-18-fluorodeoxyglucose PET/CT in amnestic and nonamnestic mild cognitive impairment patients.

OBJECTIVE: Amyloid imaging clinically is usually reported as positive or negative, and the role of amyloid topography has not been studied before. To evaluate in a clinical setting the regional distribution patterns of C-Pittsburgh compound B (C-PIB) and the fluorine-18-fluorodeoxyglucose (F-FDG) uptake in patients with mild cognitive impairment (MCI), we designed this study. METHODS: We studied 81 consecutive MCI patients, 64 amnestic (A-MCI) and 17 nonamnestic (NA-MCI) by C-PIB and F-FDG PET/computed tomography, by visual analysis. PIB retention was classified according to the regional distribution into the following patterns: A (frontal, lateral temporal, basal ganglia and anterior cingulate) and B (global retention). F-FDG images were considered positive only if temporoparietal hypometabolism consistent with Alzheimer's disease was observed. RESULTS: In 42 of the 64 A-MCI, C-PIB was positive. Twelve of the 42 positive A-MCI showed an A-pattern, all F-FDG negative, and 30 a B-pattern, 10 F-FDG positive and 20 F-FDG negative. Of the 17 NA-MCI, C-PIB was positive in three and F-FDG was positive in one. The different proportion of C-PIB positivity in A-MCI and NA-MCI was highly significant (P<0.001). CONCLUSION: Two different C-PIB patterns were observed in MCI patients and for the A-pattern, glucose hypometabolism consistent with Alzheimer's disease is highly unlikely. These findings may contribute towards a better selection of patients for future potential treatments and also to optimize the use of F-FDG-PET/CT.

Amyloid Imaging With 11C-PIB in Patients With Cognitive Impairment in a Clinical Setting: A Visual and Semiquantitative Analysis.

PURPOSE: The aim of this study was to evaluate amyloid imaging with 11C-PIB PET/CT in the study of cognitive impairment in a clinical setting. PATIENTS AND METHODS: The study included 64 patients, with a mean age of 65 years, classified as subjective memory complaints (SMCs; n = 8), nonamnestic mild cognitive impairment (NA-MCI; n = 10), amnestic MCI (A-MCI; n = 19), prodromal Alzheimer disease (AD; n = 12), suspicion of frontotemporal dementia (n = 8), Lewy bodies dementia (DLB; n = 2), and cortical degeneration (CD; n = 5). Ten healthy controls (HCs), with a mean age of 59 years, were also included. 11C-PIB was acquired 60 minutes after IV injection of 555 MBq 11C-PIB. A visual and semiquantitative analysis was performed. RESULTS: In HC, 11C-PIB was negative in 9 and positive in 1. Of the 64 patients, 11C-PIB was negative in 27 (42%) and positive in 37 (58%). 11C-PIB was positive in 3 of 8 SMC, in none of 10 NA-MCI, in 14 of 19 A-MCI, in 10 of 12 prodromal AD, in 3 of 8 frontotemporal dementia, and in the 2 and 5 DLB and CD patients. The semiquantitative results in terms of mean global SUV ratio were 1.13 for HC, 1.36 for SMC, 1.07 for NA-MCI, 2.01 for A-MCI, 2.37 for prodromal AD, 2.75 for DLB, and 2.44 for CD. CONCLUSIONS: In a clinical setting, 11C-PIB scan had a relevant contribution on patients with cognitive impairment, excluding AD in a high proportion of MCI patients and differentiating AD from other dementias. In A-MCI, 11C-PIB revealed ß-amyloid deposit in 74%, whereas it was negative in all NA-MCI patients.

Diagnosis of recurrence and assessment of post-recurrence survival in patients with extracranial non-small cell lung cancer evaluated by 18F-FDG PET/CT.

UNLABELLED: The accurate diagnosis of recurrence of non small cell lung cancer (NSCLC) is crucial for the appropriate management of patients with suspicion of recurrence (SOR). We evaluated prospectively in the clinical setting the contribution of FDG PET/CT in patients with SOR of NSCLC in terms of sensitivity, specificity, impact on therapy and on survival. METHODS: Of the 55 patients included in the study, recurrence was confirmed in 37 but, follow up data for survival evaluation was available in 34. There were 59 SOR in the 55 patients and in 41 recurrence was confirmed. 53 of the 59 suspicions, had a contrast enhanced CT. All patients had a FDG PET/CT scan after iv injection of 8 MBq/kg of F18-FDG. RESULTS: Of the 59 SOR, FDG PET/CT was positive in all 41 in which recurrence was confirmed (100% sensitivity) and, it was negative in 15 of the 18 in which it was ruled out (specificity 83%). In 27 SOR with inconclusive CT, FDG PET/CT showed 100% sensitivity (18/18) and 78% specificity (7/9). FDG PET/CT had an impact on treatment in 42 of the 59 SOR. In all 34 patients, FDG PET/CT diagnosed recurrence and overall survival at 20 months and 5 years was 44% and 11%, respectively. When the extent of recurrence assessed by FDG PET/CT was considered, survival at 20 months and at 5 years of patients with loco-regional recurrence was 77% and 28% and in patients with distant recurrence 14% and 0% (p < 0.001). CONCLUSION: Despite the small number of patients, our study demonstrates that FDG PET/CT is highly accurate for the detection of NSCLC recurrence. Therefore it has a great impact on the therapy regimen and on survival depending on the extent of the recurrent disease, survival being better for patients with local recurrence. By differentiating local from distant recurrence, it allows the selection of patients who, could potentially benefit from new therapies. The results also suggest that there are grounds to include FDG PET/CT in the guidelines for surveillance for NSCLC.

New insight of molecular imaging into the atheroma biology: (18)F-fluoride PET/CT and 18F-FDG PET/CT of 3 carotid plaques in a symptomatic neurologic patient.

In a 75-year-old patient admitted with a middle cerebral artery stroke, a contrast-enhanced CT showed 3 atheroma plaques. Five days after the stroke, a F-fluoride PET/CT to evaluate calcification and, 24 hours later, a F-FDG PET/CT to evaluate inflammation were carried out. The different metabolic behavior of both radiotracers, showing different intensities and distribution in each plaque, may represent different phases of the atherogenesis and in combination could provide new information for the early identification of the carotid unstable plaque.

Temporal hypoperfusion assessed by cerebral blood flow SPECT and long-term clinical outcome in patients with eating disorders.

OBJECTIVE: To evaluate the relationship between temporal hypoperfusion in the acute phase of patients with eating disorders and the long-term clinical outcome. METHOD: Brain perfusion was studied using Tc-99m HMPAO SPECT in 17 patients with eating disorders (ED) and compared with 12 controls (C). Semiquantitative analysis was carried out by left/right indexes. Clinical records were reviewed 15 years later and the patients were classified into 2 groups: bad outcome in 10 patients and good outcome in 4. The results of the basal SPECT were compared with the clinical outcome. RESULTS: The mean of the differences of temporal perfusion in the lower slice was 0.1476 +/- 0.1121 in ED and 0.03 +/- 0.019 in C (P < 0.001). Comparisons between C and bad outcome showed a significant difference (P < 0.01). There was no significant difference between good outcome and C. CONCLUSIONS: The temporal hypoperfusion in the acute phase of patients with ED showed a correlation with the long-term clinical outcome and suggested a prognostic value of temporal hypoperfusion.