Tomografía computarizada con energía espectral en la diferenciación de los adenomas y metástasis suprarrenales: utilidad de los mapas de descomposición de materiales y de imágenes monocromáticas / Dual-energy CT in the differentiation between adrenal adenomas and metastases: usefulness of material density maps and monochromatic images

Objetivo: Evaluar el comportamiento de los adenomas y las metástasis suprarrenales mediante TC con energía espectral, analizando el coeficiente de atenuación en imágenes monocromáticas a tres niveles energéticos diferentes (45, 70 y 140KeV), y la concentración tisular de grasa, agua y iodo obtenidos en los mapas de descomposición de materiales, con el fin de establecer puntos de corte óptimos que permitan diferenciarlos, y comparar nuestros resultados con la evidencia publicada. Materiales y métodos: Se diseñó un estudio retrospectivo de casos y controles que incluyó pacientes oncológicos con diagnóstico de metástasis suprarrenal en los 6-12 meses anteriores al estudio y con seguimiento en el Hospital entre enero y junio de 2020. Por cada caso (paciente con metástasis) incluido en el estudio se seleccionó un control (paciente con adenoma suprarrenal) con un nódulo de tamaño similar. Todos los pacientes fueron estudiados con un equipo de TC con intercambio rápido de Kilovoltaje, con protocolo de adquisición bifásico. Se analizó la concentración de iodo en el par iodo-agua; la de grasa en el par grasa-agua y la de agua en los pares agua-iodo y agua-grasa, tanto en fases arterial como portal. También se analizó el coeficiente de atenuación en imágenes monocromáticas (a 55, 70 y 140KeV) en fases arterial y portal. Resultados: En las imágenes monocromáticas, el coeficiente de atenuación fue significativamente mayor en el grupo de las metástasis que en el grupo de los adenomas en todos los niveles energéticos, tanto en fase arterial como en fase portal....(AU)

Objective: To evaluate the behavior of adrenal adenomas and metastases with dual-energy CT, analyzing the attenuation coefficient in monochromatic images at three different levels of energy (45, 70, and 140KeV) and the tissue concentrations of fat, water, and iodine in material density maps, with the aim of establishing optimal cutoffs for differentiating between these lesions and comparing our results against published evidence. Materials and methods: This retrospective case-control study included oncologic patients diagnosed with adrenal metastases in the 6-12 months prior to the study who were followed up in our hospital between January and June 2020. For each case (patient with metastases) included in the study, we selected a control (patient with an adrenal adenoma) with a nodule of similar size. All patients were studied with a rapid-kilovoltage-switching dual-energy CT scanner, using a biphasic acquisition protocol. We analyzed the concentration of iodine in paired water-iodine images, the concentration of fat in the paired water-fat images, and the concentration of water in the paired iodine-water and fat-water images, in both the arterial and portal phases. We also analyzed the attenuation coefficient in monochromatic images (at 55, 70, and 140KeV) in the arterial and portal phases. Results: In the monochromatic images, in both the arterial and portal phases, the attenuation coefficient at all energy levels was significantly higher in the group of patients with metastases than in the group of patients with adenomas. This enabled us to calculate the optimal cutoffs for classifying lesions as adenomas or metastases, except for the arterial phase at 55KeV, where the area under the receiver operating characteristic curve (AUC) for the estimated threshold (0.68) was not considered accurate enough to classify the lesions...(AU)

Dual-energy CT in the differentiation between adrenal adenomas and metastases: Usefulness of material density maps and monochromatic images.

OBJECTIVE: To evaluate the behavior of adrenal adenomas and metastases with dual-energy CT, analyzing the attenuation coefficient in monochromatic images at three different levels of energy (45, 70, and 140 keV) and the tissue concentrations of fat, water, and iodine in material density maps, with the aim of establishing optimal cutoffs for differentiating between these lesions and comparing our results against published evidence. MATERIALS AND METHODS: This retrospective case-control study included oncologic patients diagnosed with adrenal metastases in the 6-12 months prior to the study who were followed up in our hospital between January and June 2020. For each case (patient with metastases) included in the study, we selected a control (patient with an adrenal adenoma) with a nodule of similar size. All patients were studied with a rapid-kilovoltage-switching dual-energy CT scanner, using a biphasic acquisition protocol. We analyzed the concentration of iodine in paired water-iodine images, the concentration of fat in the paired water-fat images, and the concentration of water in the paired iodine-water and fat-water images, in both the arterial and portal phases. We also analyzed the attenuation coefficient in monochromatic images (at 55, 70, and 140 keV) in the arterial and portal phases. RESULTS: In the monochromatic images, in both the arterial and portal phases, the attenuation coefficient at all energy levels was significantly higher in the group of patients with metastases than in the group of patients with adenomas. This enabled us to calculate the optimal cutoffs for classifying lesions as adenomas or metastases, except for the arterial phase at 55 KeV, where the area under the receiver operating characteristic curve (AUC) for the estimated threshold (0.68) was not considered accurate enough to classify the lesions. For the arterial phase at 70 keV, the AUC was 0.76 (95% CI: 0.663‒0.899); the optimal cutoff (42.4 HU) yielded 92% sensitivity and 60% specificity. For the arterial phase at 140 keV, the AUC was 0.94 (95% CI: 0.894‒0.999); the optimal cutoff (18.9 HU) yielded 88% sensitivity and 94% specificity). For the portal phase at 55 keV, the AUC was 0.76 (95% CI: 0.663‒0.899); the optimal cutoff (95.4 HU) yielded 68% sensitivity and 84% specificity. For the portal phase at 70 keV, the AUC was 0.82 (95% CI: 0.757‒0.955); the optimal cutoff (58.4 HU) yielded 80% sensitivity and 84% specificity. For the portal phase at 140 keV, the AUC was 0.9 (95% CI: 0.834‒0.987); the optimal cutoff (16.35 HU) yielded 96% sensitivity and 84% specificity. In the material density maps, in the arterial phase, significant differences were found only for the iodine-water pair, where the concentration of water was higher in the group with metastases (1018.8 ±â€¯7.6 mg/cm3 vs. 998.6 ±â€¯8.0 mg/cm3 for the group with adenomas, p < 0.001). The AUC was 0.97 (95% CI: 0.893‒0.999); the optimal cutoff (1012.5 mg/cm3) yielded 88% sensitivity and 96% specificity. The iodine-water pair was also significantly higher in metastases (1019.7 ±â€¯12.1 mg/cm3 vs. 998.5 ±â€¯9.1 mg/cm3 in adenomas, p < 0.001). The AUC was 0.926 (95% CI: 0.807‒0.977); the optimal cutoff (1009.5 mg/cm3) yielded 92% sensitivity and 92% specificity. Although significant results were also observed for the fat-water pair in the portal phase, the AUC was insufficient to enable a sufficiently accurate cutoff for classifying the lesions. No significant differences were found in the fat-water maps or iodine-water maps in the arterial or portal phase or in the water-fat map in the arterial phase. CONCLUSIONS: Monochromatic images show differences between the behavior of adrenal adenomas and metastases in oncologic patients studied with intravenous-contrast-enhanced CT, where the group of metastases had higher attenuation than the group of adenomas in both the arterial and portal phases; this pattern is in line with the evidence published for adenomas. Nevertheless, to our knowledge, no other publications report cutoffs for this kind of differentiation in contrast-enhanced monochromatic images obtained in rapid-kilovoltage-switching dual-energy CT scanners, and this is the first new contribution of our study. Regarding the material density maps, our results suggest that the water-iodine pair is a good tool for differentiating between adrenal adenomas and metastases, in both the arterial and portal phases. We propose cutoffs for differentiating these lesions, although to our knowledge no cutoffs have been proposed for portal-phase contrast-enhanced images obtained with rapid-kilovoltage-switching dual-energy CT scanners.

Essential Subcortical Tracts in Language and Reading. 3D-Tractography for Clinical Practice and Anatomic Correlation with Intraoperative Subcortical Electrostimulation.

Diffusion tensor imaging (DTI) and tractography provide the neurosurgeon with a valid 3D view of the white matter tracts of the brain for the presurgical planning of the treatment of lesions close to eloquent areas, this being one of the principal clinical applications of this technique. In this article, we describe through practical cases the anatomic relationships of white matter tracts that are essential for language and reading, based on DTI studies and the excellent anatomic correlation with the intraoperative subcortical map.

Vólvulos del tracto gastrointestinal. Diagnóstico y correlación entre radiología simple y tomografía computarizada multidetector / Gastrointestinal tract volvulus: diagnosis and correlation between plain-film X-ray and multidetector computed tomography findings

Los vólvulos del tracto gastrointestinal constituyen una causa importante de abdomen agudo, no tanto por su frecuencia como por la gravedad de sus posibles complicaciones. Todos ellos tienen un mecanismo fisiopatológico común que consiste en una obstrucción intestinal en asa cerrada que provoca una isquemia. Las manifestaciones clínicas son inespecíficas por lo que el radiólogo tiene un papel muy importante para identificar precozmente los signos de torsión más comunes, como «el pico de pájaro» o «el remolino», y los signos de isquemia potencialmente reversible o irreversible. El tratamiento de elección en la mayoría de los casos es quirúrgico, bien para corregir las causas y preservar el órgano volvulado, o para resecarlo en caso de necrosis (AU)

Gastrointestinal volvuli cause processes that manifest as acute abdomen. Volvuli are important not because they are common, but rather because their possible complications can be severe. All types of volvuli share a common pathophysiology, which consists of intestinal obstruction in a closed loop that results in ischemia. The clinical manifestations are nonspecific, so radiologists play a very important role in the early identification of the most common signs of torsion. These include the «bird's beak sign», the «whirlpool sign», and signs of potentially reversible or irreversible ischemia. The treatment of choice in most cases is surgery, either to correct the torsion and save the organ or to resect it if it is necrotic (AU)

[Gastrointestinal tract volvulus: diagnosis and correlation between plain-film X-ray and multidetector computed tomography findings]. / Vólvulos del tracto gastrointestinal. Diagnóstico y correlación entre radiología simple y tomografía computarizada multidetector.

Gastrointestinal volvuli cause processes that manifest as acute abdomen. Volvuli are important not because they are common, but rather because their possible complications can be severe. All types of volvuli share a common pathophysiology, which consists of intestinal obstruction in a closed loop that results in ischemia. The clinical manifestations are nonspecific, so radiologists play a very important role in the early identification of the most common signs of torsion. These include the "bird's beak sign", the "whirlpool sign", and signs of potentially reversible or irreversible ischemia. The treatment of choice in most cases is surgery, either to correct the torsion and save the organ or to resect it if it is necrotic.

La patología benigna de ano y recto con RM 3.0T. 2.a Parte: patología inflamatoria ano-rectal. Anatomía postquirúrgica y complicaciones postratamiento / 3.0T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part 2: anorectal inflammatory disease. Postsurgical anatomy and complications after treatment

La patología benigna anorrectal comprende una vasta cantidad de entidades de muy diversos orígenes, congénitas o adquiridas, inflamatorias o tumorales. Sin embargo, ha recibido menos atención en la bibliografía científica que el estudio de la patología tumoral maligna. En esta segunda entrega de la revisión basada en imágenes de la patología benigna anorrectal describimos la patología inflamatoria y fistulosa más frecuente, la anatomía posquirúrgica y las complicaciones secundarias al tratamiento quirúrgico o radioterápico de la patología anorrectal (AU)

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. In this second part of this image-based review of benign anorectal disease, we describe the most common inflammatory and fistulous diseases, the postsurgical anatomy, and complications that can occur after surgical treatment or radiotherapy for anorectal disease (AU)

Disfunción del tendón tibial posterior: ¿qué otras estructuras están implicadas en el desarrollo del pie plano adquirido del adulto? / Posterior tibial tendon dysfunction: what other structures are involved in the development of acquired adult flat foot?

Objetivo: Valorar la asociación entre disfunción del tendón tibial posterior (DTTP), las lesiones de diversas estructuras del tobillo diagnosticadas por RM, y los signos radiológicos del pie plano. Material y método: Realizamos un estudio retrospectivo comparando 29 pacientes con DTTP, todos examinados por RM (21 de ellos con un estudio radiológico en carga) y un grupo control de 28 pacientes elegidos aleatoriamente entre aquellos estudiados por otras afecciones del tobillo mediante RM y estudio radiológico en carga. En los estudios de RM revisamos la existencia de espolón calcáneo, pico talar, fascitis plantar, edema óseo calcáneo, tendinopatía del Aquiles, lesión del ligamento Spring, afección del seno del tarso y coalición tarsiana. En los estudios radiológicos en carga se valoraron el ángulo de Costa-Bertani y los signos radiológicos de pie plano. Analizamos las diferencias entre los grupos en los hallazgos con RM y presencia de pie plano mediante el test exacto de Fisher y del ángulo de Costa-Bertani mediante el análisis de lavarianza. Resultados: La presencia de espolón calcáneo, pico talar, afección del seno del tarso y del ligamento Spring fue más frecuente en el grupo con DTTP, de forma estadísticamente significativa (p < 0,05). También existieron diferencias significativas en la presencia del pie plano radiológico y valores anómalos en el ángulo de Costa-Bertani, más frecuentes (p < 0,001) en el grupo con DTTP. Conclusión: Corroboramos la asociación entre la lesión de estas estructuras diagnosticada por RM y los signos del pie plano radiológico con DTTP. Conocer esta asociación puede ser de utilidad para establecer un diagnóstico preciso (AU)

Objective: To evaluate the association of posterior tibial tendon dysfunction and lesions of diverse ankle structures diagnosed at MRI with radiologic signs of flat foot. Material and methods: We retrospectively compared 29 patients that had posterior tibial tendon dysfunction (all 29 studied with MRI and 21 also studied with weight-bearing plain-film X-rays) with a control group of 28 patients randomly selected from among all patients who underwent MRI and weight-bearing plain-film X-rays for other ankle problems. In the MRI studies, we analyzed whether a calcaneal spur, talar beak, plantar fasciitis, calcaneal bone edema, Achilles’ tendinopathy, spring ligament injury, tarsal sinus disease, and tarsal coalition were present. In the weight-bearing plain-film X-rays, we analyzed the angle of Costa-Bertani and radiologic signs of flat foot. To analyze the differences between groups, we used Fisher’s exact test for the MRI findings and for the presence of flat foot and analysis of variance for the angle of Costa-Bertani. Results: Calcaneal spurs, talar beaks, tarsal sinus disease, and spring ligament injury were significantly more common in the group with posterior tibial tendon dysfunction (P<.05). Radiologic signs of flat foot and anomalous values for the angle of Costa-Bertani were also significantly more common in the group with posterior tibial tendon dysfunction (P<.001). Conclusion: We corroborate the association between posterior tibial tendon dysfunction and lesions to the structures analyzed and radiologic signs of flat foot. Knowledge of this association can be useful in reaching an accurate diagnosis (AU)

La patología benigna de ano y recto con Resonancia Magnética 3.0T. 1 a Parte: Protocolo de alta resolución, revisión anatómica, tumores benignos y alteraciones congénitas o adquiridas del complejo esfinteriano / 3.0 T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part one: High resolution protocol for 3.0 T MRI, anatomic review, benign tumors, and congenital or acquired alterations of the sphincter complex

La patología benigna anorrectal comprende una amplio grupo de procesos de muy diversos orígenes, congénitos o adquiridos, inflamatorios o tumorales. Sin embargo, ha recibido en la bibliografía científica menor atención que el estudio de la patología tumoral maligna. Presentamos una revisión basada en imágenes de la patología benigna anorrectal más frecuente. En esta primera parte realizamos un recuerdo anatómico y una breve descripción de las peculiaridades del protocolo de alta resolución que empleamos con la RM de 3.0 T. Después describimos los principales tumores benignos anorrectales y lesiones quísticas del desarrollo junto con sus principales diagnósticos diferenciales y las anomalías congénitas y adquiridas del complejo esfinteriano anorrectal (AU)

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. We present an image-based review of the most common benign diseases of the anus and rectum. In this first part, we review the anatomy of the region and provide a brief description of the peculiarities of the high resolution protocol that we use with 3.0 T MRI. We go on to describe the most common benign anorectal tumors and developmental cystic lesions, together with their differential diagnoses, as well as congenital and acquired anomalies of the anorectal sphincter complex (AU)

[Posterior tibial tendon dysfunction: what other structures are involved in the development of acquired adult flat foot?]. / Disfunción del tendón tibial posterior: ¿qué otras estructuras están implicadas en el desarrollo del pie plano adquirido del adulto?

OBJECTIVE: To evaluate the association of posterior tibial tendon dysfunction and lesions of diverse ankle structures diagnosed at MRI with radiologic signs of flat foot. MATERIAL AND METHODS: We retrospectively compared 29 patients that had posterior tibial tendon dysfunction (all 29 studied with MRI and 21 also studied with weight-bearing plain-film X-rays) with a control group of 28 patients randomly selected from among all patients who underwent MRI and weight-bearing plain-film X-rays for other ankle problems. In the MRI studies, we analyzed whether a calcaneal spur, talar beak, plantar fasciitis, calcaneal bone edema, Achilles' tendinopathy, spring ligament injury, tarsal sinus disease, and tarsal coalition were present. In the weight-bearing plain-film X-rays, we analyzed the angle of Costa-Bertani and radiologic signs of flat foot. To analyze the differences between groups, we used Fisher's exact test for the MRI findings and for the presence of flat foot and analysis of variance for the angle of Costa-Bertani. RESULTS: Calcaneal spurs, talar beaks, tarsal sinus disease, and spring ligament injury were significantly more common in the group with posterior tibial tendon dysfunction (P<.05). Radiologic signs of flat foot and anomalous values for the angle of Costa-Bertani were also significantly more common in the group with posterior tibial tendon dysfunction (P<.001). CONCLUSION: We corroborate the association between posterior tibial tendon dysfunction and lesions to the structures analyzed and radiologic signs of flat foot. Knowledge of this association can be useful in reaching an accurate diagnosis.

[3.0 T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part one: High resolution protocol for 3.0 T MRI, anatomic review, benign tumors, and congenital or acquired alterations of the sphincter complex]. / La patología benigna de ano y recto con Resonancia Magnética 3.0T. 1a Parte: Protocolo de alta resolución, revisión anatómica, tumores benignos y alteraciones congénitas o adquiridas del complejo esfinteriano.

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. We present an image-based review of the most common benign diseases of the anus and rectum. In this first part, we review the anatomy of the region and provide a brief description of the peculiarities of the high resolution protocol that we use with 3.0 T MRI. We go on to describe the most common benign anorectal tumors and developmental cystic lesions, together with their differential diagnoses, as well as congenital and acquired anomalies of the anorectal sphincter complex.

[3.0T MRI with a high resolution protocol for the study of benign disease of the anus and rectum. Part 2: Anorectal inflammatory disease. Postsurgical anatomy and complications after treatment]. / La patología benigna de ano y recto con RM 3.0T. 2.(a) Parte: patología inflamatoria ano-rectal. Anatomía postquirúrgica y complicaciones postratamiento.

Benign anorectal disease comprises a broad group of processes with very diverse origins; these processes may be congenital or acquired as well as inflammatory or tumor related. However, benign anorectal disease has received less attention in the scientific literature than malignant disease. In this second part of this image-based review of benign anorectal disease, we describe the most common inflammatory and fistulous diseases, the postsurgical anatomy, and complications that can occur after surgical treatment or radiotherapy for anorectal disease.

Papel de las técnicas de imagen en la nueva clasificación TNM del carcinoma broncogénico no microcítico / Role of imaging techniques in the TNM classification of non-small cell bronchogenic carcinoma

La séptima edición de la clasificación TNM para los carcinomas broncogénicos no microcíticos incluye una serie de cambios en los descriptores T y M, particularmente una reclasificación de los derrames malignos pleurales y pericárdicos y de los nódulos tumorales separados, nuevos valores de corte de tamaño tumoral y subdivisiones de las categorías T1-T2 y M1. Revisamos estas correcciones, que generan cambios en el sistema de estadificación que afectan a los estadios II-III. Además, describimos e ilustramos el papel de las diferentes técnicas de imagen en la estadificación tumoral (TC, PET, PET-TC y RM), resaltando sus respectivas indicaciones, ventajas y desventajas, así como su función complementaria (AU)

The Seventh Edition of the TNM Classification for non-small cell bronchogenic carcinomas include a series of changes in the T and M descriptor, in particular a re-classification of malignant pleural and pericardial effusions and of separated tumour nodes, new tumour size cut-off values and sub-divisions of the T1-T2 and M1 categories. We review these corrections that led to the changes in the staging system that affects stages II-III. Furthermore, we describe and illustrate the role of the different imaging techniques in tumour staging (CT, PET, PET-CT and MRI), highlighting their respective indications, advantages and disadvantages, as well their complementary function (AU)

[Role of imaging techniques in the TNM classification of non-small cell bronchogenic carcinoma]. / Papel de las técnicas de imagen en la nueva clasificación TNM del carcinoma broncogénico no microcítico.

The Seventh Edition of the TNM Classification for non-small cell bronchogenic carcinomas include a series of changes in the T and M descriptor, in particular a re-classification of malignant pleural and pericardial effusions and of separated tumour nodes, new tumour size cut-off values and sub-divisions of the T1-T2 and M1 categories. We review these corrections that led to the changes in the staging system that affects stages II-III. Furthermore, we describe and illustrate the role of the different imaging techniques in tumour staging (CT, PET, PET-CT and MRI), highlighting their respective indications, advantages and disadvantages, as well their complementary function.

Entero-resonancia magnética: revisión de la técnica para el estudio de la enfermedad de Crohn / Magnetic resonance enterography: review of the technique for the study of Crohn's disease

La enfermedad de Crohn es una enfermedad crónica de curso imprevisible que requiere numerosos estudios radiológicos durante la vida. Afecta frecuentemente a pacientes jóvenes, más vulnerables a los efectos nocivos de las exploraciones repetidas con radiaciones ionizantes. La precisión diagnóstica de la enterografía por RM es similar a la de la tomografía computarizada por su alta resolución tisular, sin el inconveniente de la radiación. Los índices clínicos de valoración de la enfermedad son poco precisos y subjetivos por lo que las técnicas enterográficas de imagen se están incorporando cada vez más a la práctica clínica como medios objetivos de control de la gravedad de la enfermedad. En este artículo, describimos nuestra técnica enterográfica en RM para la valoración de la enfermedad de Crohn. Revisaremos los hallazgos más relevantes por imagen y los subtipos de la enfermedad, la literatura científica relacionada y los índices por RM en la valoración de la gravedad de la enfermedad (AU)

Crohn's disease is a chronic disease with an unpredictable course. Patients with Crohn's disease will have to undergo numerous imaging tests. Crohn's disease often affects young people, who are more vulnerable to the harmful effects of repeated exposure to ionizing radiation. The high resolution of tissues on MR enterography give it a diagnostic accuracy similar to that of CT; however, MR enterography does not have the drawback of ionizing radiation. The clinical indices used to assess Crohn's disease are subjective and not very accurate; thus, enterographic techniques are becoming more common in clinical practice as a means to follow up patients objectively. In this article, we describe the MR enterography technique we use to evaluate Crohn's disease. We illustrate the most relevant imaging findings, and we review the subtypes of the disease, the related scientific literature, and the MR indices used to assess the severity of Crohn's disease (AU)

[Magnetic resonance enterography: review of the technique for the study of Crohn's disease]. / Entero-resonancia magnética: revisión de la técnica para el estudio de la enfermedad de Crohn.

Crohn's disease is a chronic disease with an unpredictable course. Patients with Crohn's disease will have to undergo numerous imaging tests. Crohn's disease often affects young people, who are more vulnerable to the harmful effects of repeated exposure to ionizing radiation. The high resolution of tissues on MR enterography give it a diagnostic accuracy similar to that of CT; however, MR enterography does not have the drawback of ionizing radiation. The clinical indices used to assess Crohn's disease are subjective and not very accurate; thus, enterographic techniques are becoming more common in clinical practice as a means to follow up patients objectively. In this article, we describe the MR enterography technique we use to evaluate Crohn's disease. We illustrate the most relevant imaging findings, and we review the subtypes of the disease, the related scientific literature, and the MR indices used to assess the severity of Crohn's disease.