Seguimiento del cáncer de cabeza y cuello tratado. Lo que el radiólogo debe conocer / Follow-up in head and neck cancer. What the radiologist must know

El manejo de los pacientes con cáncer de cabeza y cuello implica un tratamiento multidisciplinar con cirugía, radioterapia y quimioterapia. Las pruebas de imagen son cruciales en su seguimiento, sobre todo cuando la recurrencia tumoral no sea clínicamente evidente. Distinguir radiológicamente los cambios postratamiento de una recidiva tumoral constituye un reto debido a la alteración anatómica que suponen las técnicas quirúrgicas y sus reconstrucciones, al tratamiento radioterápico y a las pautas quimioterápicas. El diagnóstico diferencial debe incluir las posibles complicaciones derivadas de la radioterapia (necrosis mucosa, osteorradionecrosis, vasculopatía, radionecrosis cerebral) y de la cirugía (infecciones de la herida, necrosis del colgajo, fístulas, etc.). Un amplio conocimiento de los hallazgos esperables del tratamiento multimodal y sus complicaciones es esencial para un diagnóstico preciso de recurrencia tumoral. Por último, elegir la prueba de imagen adecuada y disponer de un estudio basal postratamiento es igualmente relevante para un control radiológico idóneo

The management of patients with head and neck cancer implies a multidisciplinary treatment with surgery, radiotherapy and chemotherapy. Imaging is crucial in their follow-up, especially when the tumor recurrence is not clinically evident. Radiologically distinguishing post-treatment changes from a tumor recurrence is a challenge due to the anatomical alteration due to surgical techniques and their reconstructions, radiotherapy treatment and chemotherapeutic guidelines. The differential diagnosis must include the possible complications derived from radiotherapy (mucosal necrosis, osteoradionecrosis, vasculopathy, cerebral radionecrosis) and surgery (wound infections, flap necrosis, fistulas,...). A wide knowledge of the expected findings of multimodal treatment and its complications is essential for an accurate diagnosis of tumor recurrence. Finally, choosing the appropriate image study and having a baseline post-treatment study is also relevant for a suitable radiological control

Follow-up in head and neck cancer. What the radiologist must know. / Seguimiento del cáncer de cabeza y cuello tratado. Lo que el radiólogo debe conocer.

The management of patients with head and neck cancer implies a multidisciplinary treatment with surgery, radiotherapy and chemotherapy. Imaging is crucial in their follow-up, especially when the tumor recurrence is not clinically evident. Radiologically distinguishing post-treatment changes from a tumor recurrence is a challenge due to the anatomical alteration due to surgical techniques and their reconstructions, radiotherapy treatment and chemotherapeutic guidelines. The differential diagnosis must include the possible complications derived from radiotherapy (mucosal necrosis, osteoradionecrosis, vasculopathy, cerebral radionecrosis) and surgery (wound infections, flap necrosis, fistulas,...). A wide knowledge of the expected findings of multimodal treatment and its complications is essential for an accurate diagnosis of tumor recurrence. Finally, choosing the appropriate image study and having a baseline post-treatment study is also relevant for a suitable radiological control.

Efecto regional, de la edad y el sexo en la espectroscopia por resonancia magnética cerebral / Regional effects of age and sex in magnetic resonance spectroscopy

Objetivo. Estudiar con espectroscopia univóxel por resonancia magnética (1,5T) el efecto regional, de la edad y el sexo en las ratios metabólicas del lóbulo temporal medial, la región cerebral posteromedial (RPM) y el lóbulo frontal. Material y métodos. Estudiamos 31 personas sanas mayores de 55 años (grupo 1) y 20 menores de 30 años (grupo 2) con espectroscopia univóxel en el lóbulo frontal izquierdo, el lóbulo temporal medial izquierdo y la RPM, especialmente afectadas por las enfermedades neurodegenerativas. Se calcularon las ratios NAA/Cr, NAA/Cho, NAA/mI, Cho/Cr, y mI/Cr, de cada vóxel. En cada grupo se compararon regionalmente las ratios metabólicas, y se estudió la correlación ratio-edad dentro de sus rangos de edad. Finalmente, se analizaron las diferencias de las ratios metabólicas entre grupos y entre sexos. Resultados. En el grupo 1, las ratios Cho/Cr frontal y NAA/mI temporal se correlacionaron negativamente con la edad. En el grupo 2, las correlaciones con la edad fueron negativas para las ratios temporales mI/Cr y NAA/Cho, y positiva para la NAA/mI temporal. En el lóbulo frontal y la RPM, las ratios NAA/Cr, NAA/Cho y NAA/mI fueron menores en el grupo 1 (P<=0,003). Las ratios Cho/Cr y mI/Cr nunca mostraron diferencias entre grupos. Los valores de las ratios difirieron regionalmente en todos los casos (P<0,001). NAA/Cr y Cho/Cr en el lóbulo temporal medial fueron mayores en las mujeres (P<=0,034). Conclusiones. Cuando se utilice la espectroscopia univóxel por resonancia magnética, en particular en las enfermedades neurodegenerativas, siempre deben considerarse las variaciones inducidas por la región, la edad y el sexo (AU)

Objective. To determine the regional effects of age and sex on the metabolic ratios obtained in the medial temporal lobe, the posteromedial region, and the frontal lobe at 1.5T single-voxel magnetic resonance spectroscopy. Material and methods. We used single-voxel magnetic resonance spectroscopy to study the areas of the brain most affected in neurodegenerative disease (the left frontal lobe, the left medial temporal lobe, and the posteromedial region) in 31 healthy subjects older than 55 years of age (group 1) and in 20 healthy subjects under 30 years of age (group 2). We calculated the following ratios for each voxel: N-acetyl-aspartate/creatine-phosphocreatine (NAA/Cr), N-acetyl-aspartate/choline (NAA/Cho), N-acetyl-aspartate /myoinositol (NAA/mI), choline/creatine-phosphocreatine (Cho/Cr), and myoinositol (mI/Cr). We compared the metabolic ratios in each region in each group and the correlation between age and the ratios within age ranges. Finally, we analyzed the differences in the metabolic ratios between groups and between sexes. Results. In group 1, we found negative correlations between age and Cho/Cr in the frontal region and NAA/mI in the temporal region. In group 2, we found negative correlations between age and mI/Cr and NAA/Cho in the temporal region as well as a positive correlation between age and NAA/mI in the temporal region. In the frontal lobe and the posteromedial region, NAA/Cr, NAA/Cho, and NAA/mI were lower in group 1 (P<=0.003). No differences between groups were seen in Cho/Cr or mI/Cr. The values of the ratios differed regionally in all cases (P<0.001). In the temporal lobe, NAA/Cr and Cho/Cr were higher in women (P<=0.034). Conclusions. When using single-voxel magnetic resonance spectroscopy, especially in patients with neurodegenerative disease, variations due to region, age, and sex should always be taken into account (AU)

[Regional effects of age and sex in magnetic resonance spectroscopy]. / Efecto regional, de la edad y el sexo en la espectroscopia por resonancia magnética cerebral.

OBJECTIVE: To determine the regional effects of age and sex on the metabolic ratios obtained in the medial temporal lobe, the posteromedial region, and the frontal lobe at 1.5 T single-voxel magnetic resonance spectroscopy. MATERIAL AND METHODS: We used single-voxel magnetic resonance spectroscopy to study the areas of the brain most affected in neurodegenerative disease (the left frontal lobe, the left medial temporal lobe, and the posteromedial region) in 31 healthy subjects older than 55 years of age (group 1) and in 20 healthy subjects under 30 years of age (group 2). We calculated the following ratios for each voxel: N-acetyl-aspartate/creatine-phosphocreatine (NAA/Cr), N-acetyl-aspartate/choline (NAA/Cho), N-acetyl-aspartate /myoinositol (NAA/mI), choline/creatine-phosphocreatine (Cho/Cr), and myoinositol (mI/Cr). We compared the metabolic ratios in each region in each group and the correlation between age and the ratios within age ranges. Finally, we analyzed the differences in the metabolic ratios between groups and between sexes. RESULTS: In group 1, we found negative correlations between age and Cho/Cr in the frontal region and NAA/mI in the temporal region. In group 2, we found negative correlations between age and mI/Cr and NAA/Cho in the temporal region as well as a positive correlation between age and NAA/mI in the temporal region. In the frontal lobe and the posteromedial region, NAA/Cr, NAA/Cho, and NAA/mI were lower in group 1 (P≤0.003). No differences between groups were seen in Cho/Cr or mI/Cr. The values of the ratios differed regionally in all cases (P<0.001). In the temporal lobe, NAA/Cr and Cho/Cr were higher in women (P≤0.034). CONCLUSIONS: When using single-voxel magnetic resonance spectroscopy, especially in patients with neurodegenerative disease, variations due to region, age, and sex should always be taken into account.

Coeficiente de difusión aparente cerebral: diferencias por edad, sexo, lateralidad y diferente valor b / Brain apparent diffusion coefficient: differences caused by age, sex, laterality, and distinct b value

Objetivo: Analizar el efecto de la edad, el sexo y el valor b en el coeficiente de difusión aparente (CDA) de áreas cerebrales alteradas en las enfermedades neurodegenerativas. Material y métodos: Se estudió el CDA de hipocampo, rodilla y esplenio del cuerpo calloso en 50 pacientes normales, con difusión por resonancia magnética b1.000 y b3.000s/mm2. Para cada localización se calcularon las diferencias entre los CDA b1.000 y b3.000 (diferencial de difusión [DD]). Se separaron los pacientes en grupos de edad (⩽30, 31–60 y >60 años). El análisis de las diferencias de CDA y DD entre grupos de edad y entre sexos se hizo con los tests de ANOVA y Kruskal-Wallis, y la corrección de Bonferroni. Para la correlación del CDA y el DD con la edad se utilizó el test de Pearson. Resultados: En el hipocampo derecho hubo diferencias de CDA (b1.000, p=0,011; b3.000, p=0,024) y DD (p=0,006) con la edad. Las diferencias del CDA se observaron entre los grupos de 31–60 años y >60 (p=0,009) para b 1.000, y entre<30 y 31–60 años (p=0,036) para b 3.000. El DD varió entre los >60 años y el resto. En el cuerpo calloso hubo diferencias significativas entre sexos en el DD de la rodilla (p=0,016). El DD mostró correlación con la edad en el hipocampo derecho (r=0,321, p=0,023). Conclusiones: Nuestros datos indican mayor estabilidad de los valores de CDA medidos con b3.000 durante el envejecimiento. El análisis del CDA con valor b más alto puede ser de utilidad en las enfermedades neurodegenerativas (AU)

Objective: To analyze the effects of age, sex, and b value on the apparent diffusion coefficient (ADC) in brain areas affected by neurodegenerative diseases. Material and methods: We studied the ADC of the genu and splenium of the corpus callosum and of the hippocampus in normal patients using diffusion magnetic resonance imaging (dMRI) with b1,000s/mm2 and b3,000s/mm2. We calculated the differences between the ADC (diffusion differential [DD]) with b1,000 and with b3,000 for each region. Patients were classified into the following age groups (⩽30 years old, 31–60 years old, >60 years old). We used a Kruskal-Wallis one-way ANOVA and the Bonferroni correction to analyze the differences in ADC and DD between age groups and between sexes. Pearson's chi-square test was used to correlate the ADC and DD with age. Results: In the right hippocampus, we observed differences in ADC (b1,000, p=0.011; b3,000, p=0.024) and DD (p=0.006) with age. Differences in ADC were observed between the 31–60 year-old age group and the >60 year-old age group (p=0.009) for b1,000, and between the<30 year-old age group and the 31–60 year-old age group (p=0.036) for b3,000. The DD in the >60 year-old age group was different from the rest. In the corpus callosum, there were significant differences between sexes in the DD of the genu (p=0.016). The DD was correlated with age in the right hippocampus (r=0.321, p=0.023). Conclusions: Our data indicate greater stability in mean ADC values with b3000 during aging. It might be useful to analyze the ADC with a higher b in patients with neurodegenerative diseases (AU)

[Brain apparent diffusion coefficient: differences caused by age, sex, laterality, and distinct b value]. / Coeficiente de difusión aparente cerebral: diferencias por edad, sexo, lateralidad y diferente valor b.

OBJECTIVE: To analyze the effects of age, sex, and b value on the apparent diffusion coefficient (ADC) in brain areas affected by neurodegenerative diseases. MATERIAL AND METHODS: We studied the ADC of the genu and splenium of the corpus callosum and of the hippocampus in normal patients using diffusion magnetic resonance imaging (dMRI) with b1,000 s/mm2 and b3,000 s/mm2. We calculated the differences between the ADC (diffusion differential [DD]) with b1,000 and with b3,000 for each region. Patients were classified into the following age groups (60 years old). We used a Kruskal-Wallis one-way ANOVA and the Bonferroni correction to analyze the differences in ADC and DD between age groups and between sexes. Pearson's chi-square test was used to correlate the ADC and DD with age. RESULTS: In the right hippocampus, we observed differences in ADC (b1,000, p=0.011; b3,000, p=0.024) and DD (p=0.006) with age. Differences in ADC were observed between the 31-60 year-old age group and the >60 year-old age group (p=0.009) for b1,000, and between the<30 year-old age group and the 31-60 year-old age group (p=0.036) for b3,000. The DD in the >60 year-old age group was different from the rest. In the corpus callosum, there were significant differences between sexes in the DD of the genu (p=0.016). The DD was correlated with age in the right hippocampus (r=0.321, p=0.023). CONCLUSIONS: Our data indicate greater stability in mean ADC values with b3000 during aging. It might be useful to analyze the ADC with a higher b in patients with neurodegenerative diseases.

Magnetic resonance spectroscopy performance for detection of dementia, Alzheimer's disease and mild cognitive impairment in a community-based survey.

BACKGROUND/AIMS: To evaluate (1)H-labelled magnetic resonance spectroscopy (MRS) in patients with a low Mini Mental State Examination (MMSE) score identified during a dementia community-based survey. METHODS: A population sample of 1,500 individuals (>64 years old) was randomly selected. Two hundred and fifteen individuals (MMSE < or =24) were sorted into clinical groups: dementia, Alzheimer's disease, mild cognitive impairment (MCI), normal. Up to 56 of these individuals attended the MRS appointment. Two single-voxel sequences (TR 1,500, TE 35/144 ms) were carried out in the posterior cingulate gyrus of each individual, and the ratios N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, myo-inositol (mI)/Cr, NAA/mI and NAA/Cho were compared statistically. The ability of MRS to distinguish clinical groups was assessed by receiver-operating characteristics analysis. Cognition effects on metabolite ratios were estimated, with gender and cognition as categorical variables and age as a continuous covariate. RESULTS: NAA/Cr and NAA/Cho ratios were lower in dementia or Alzheimer's disease than in MCI and normal groups. The NAA/Cr ratio at TE 35 ms performed best when distinguishing dementia or Alzheimer's disease from non-demented subjects (cut-off point 1.40). MRS could not distinguish between MCI patients and normal subjects. Dementia was an independent predictor of metabolite values. CONCLUSION: In a population sample, conventional MRS still proved to be a useful tool for dementia discrimination, but it is potentially far less useful as a surrogate marker for MCI.