Secuencia de disparo único eco de gradiente en fase y fase opuesta con preparación de la magnetización: descripción y optimización de la técnica con equipo de 1,5 T

Purpose

To implement in-phase and out-of-phase (IP/OP) techniques with Magnetization-Prepared Gradient Recalled Echo (MP-GRE) and to evaluate the feasibility and diagnostic image quality among pre and post-optimized MP-GRE sequences, including patients unable to cooperate with breath-hold requirements.

Materials and methods

Institutional review board approval with waiver of informed consent was obtained for this HIPAA-compliant retrospective study. Two groups of patients were included in the study, before and after optimization of MP-GRE parameters, with seventy-three (24 noncooperative/49 cooperative) and sixty-four (22 noncooperative/42 cooperative) consecutive patients, respectively. The motion-insensitive sequence used in this study was a single-shot 2D MP-GRE. Two radiologists qualitatively evaluated the sequences to identify the presence of phase cancellation artifact in OP images and to determine image quality, extent of artifacts (respiratory ghosting, bounce-point artifact, spatial misregistration and pixel graininess) and lesion conspicuity on the various sequences. The ability to visually detect liver steatosis and fatty adrenal adenomas was evaluated. Qualitative analyses were compared using the Wilcoxon and Mann-Whitney tests.

Results

There were statistically significant differences between all MP-GRE sequences concerning phase cancellation artifact (P<.0001) which was present in MP-GRE OP sequences and negligible to absent in the pre (IP₁) and post-optimized (IP₂) MP-GRE IP sequences, respectively, in all patients.Bounce point artifacts were significantly more pronounced in MP-GRE IP₁ (P<.0001). Spatial misregistration was slightly more prominent in noncooperative patients with MP-GRE IP₂ (P=.0027). MP-GRE OP and MP-GRE IP₂ showed significantly higher overall image quality (P<.0001).MP-GRE sequences subjectively identified hepatic steatosis (n=20) and adrenal adenomas (n=5) based on signal loss from IP to OP sequence.

Conclusion

Single shot IP/OP MP-GRE is feasible and allows motion resistant imaging with adequate diagnostic image quality. This technique is able to provide IP and OP information in patients unable to suspend respiration.     

Medición del T2* hepático y cardíaco en la hemocromatosis secundaria

Objective

To determine whether there is iron overload by calculating the T2* value in the liver and myocardium in patients with secondary haemochromatosis. To analyse the correlation of the values obtained with the iron levels in blood, with the liver iron concentration (LIC) calculated using magnetic resonance (MR) imaging, and the correlation between them.

Material and methods

A total of 16 patients (13 males, 3 females), with a mean age of 61 years, were included and evaluated in the years 2008 and 2009. Fifteen of them had received multiple transfusions, and one was diagnosed with hereditary sideroblastic anaemia.The measurements included, blood ferritin, LIC by MRI, cardiac function using MRI and the T2* value by means of multi-echo sequences in the liver (TR/TE1/ΔTE/No of echos/α: 21/1,18/1.0/20/35°) and myocardium (26/1.04/0.8/30/60°). A correlation-regression analysis was performed by comparing the cardiac and liver T2* values with the ferritin, LIC and between each of them.

Results

A total of 13 patients had ferritin values greater than 1000 ng/ml (median/minimum/maximum: 1762/294/3785 ng/ml). An increased LIC greater than 80 μmol/g (median/minimum/maximum: 125.4/41.2/241.5 μmol/g) was observed in 13 patients. In all cases cardiac function was conserved, and in 15 cases the liver T2* value was less than 6.3 ms. The myocardium T2* value was less than 20 ms. in only one case. A high correlation was observed between the liver T2* values and the LIC (r: -0.912). The correlation was statistically significant between the liver T2* value and ferritin (r: -0.541). The correlations between myocardium T2* and ferritin, myocardium T2* and LIC, and myocardium T2* and liver T2* were not statistically significant.

Conclusions

The liver T2* showed a high correlation with LIC and a statistically significant correlation with ferritin. No association was observed between the myocardium T2* values and ferritin in blood, the LIC or the liver T2* value.     

Reproducibilidad y exactitud en la cuantificación morfométrica y mecánica del hueso trabecular a partir de imágenes de resonancia magnética de Tesla

Objective

We used an animal model to analyze the reproducibility and accuracy of certain biomarkers of bone image quality in comparison to a gold standard of computed microtomography (μCT).

Material and methods

We used magnetic resonance (MR) imaging and μCT to study the metaphyses of 5 sheep tibiae. The MR images (3 Teslas) were acquired with a T1-weighted gradient echo sequence and an isotropic spatial resolution of 180 μm. The μCT images were acquired using a scanner with a spatial resolution of 7.5 μm isotropic voxels. In the preparation of the images, we applied equalization, interpolation, and thresholding algorithms. In the quantitative analysis, we calculated the percentage of bone volume (BV/TV), the trabecular thickness (Tb.Th), the trabecular separation (Tb.Sp), the trabecular index (Tb.N), the 2 D fractal dimension (D^2D), the 3 D fractal dimension (D^3D), and the elastic module in the three spatial directions (Ex, Ey and Ez).

Results

The morphometric and mechanical quantification of trabecular bone by MR was very reproducible, with percentages of variation below 9% for all the parameters. Its accuracy compared to the gold standard (μCT) was high, with errors less than 15% for BV/TV, D^2D, D^3D, and E_appx, E_appy and E_appz.

Conclusions

Our experimental results in animals confirm that the parameters of BV/TV, D^2D, D^3D, and E_appx, E_appy and E_appz obtained by MR have excellent reproducibility and accuracy and can be used as imaging biomarkers for the quality of trabecular bone.     

Manifestaciones radiológicas del síndrome de Baastrup en la edad pediátrica

Baastrup's disease is not usually considered among the possible causes of low back pain in children. Classically, Baastrup's disease is characterized by degenerative phenomena secondary to friction between adjacent spinous processes, with sclerosis of the margins and decrease in the interspinous space. Baastrup's disease becomes more prevalent with age and is usually accompanied by degenerative changes in the vertebral column, such as lumbar facet hypertrophy or disc disease. Certain activities like dance or gymnastics can make Baastrup's disease more likely to appear at an earlier age. In children, Baastrup's disease can manifest in a different way, with increased interspinous spaces and bone remodeling.     

Miofibromatosis infantil. Un caso estudiado con ecografía y resonancia magnética de cuerpo entero

Infantile myofibromatosis, despite being considered a rare condition, is the most common fibrous tumour in infancy. It is characterised by the presence of benign fibroblastic-myofibroblastic lesions. It usually occurs in children under two years-old, but it can appear at any age. The solitary form (myofibromas) may affect the skin, subcutaneous cellular tissue, muscle or bone. In the multi-centred form (myofibromatosis), there may also be visceral lesions. The lesions usually regress spontaneously in one or two years, with the prognosis being excellent in these cases. However, when there is visceral involvement, the prognosis is poor and treatment with chemotherapy is indicated. Lung involvement is more associated with a poor prognosis. Although the definitive diagnosis is by histopathology, diagnostic imaging tests are essential for characterising the lesions, establishing the extent of the disease, assessing visceral involvement, and following up the progression of the lesions.     

Coronariografía mediante tomografía computarizada con sincronización prospectiva. Comparación de la calidad de imagen y dosis de radiación con equipos de 128 detectores de fuente única y doble fuente

Objective

To compare the image quality and radiation dose in a group of patients undergoing coronary CT angiography using a 128-slice dual source helical CT scanner with high pitch alto and prospective acquisition with those in a group of patients with similar clinical characteristics undergoing coronary CT angiography using a 128-slice single-source CT scanner with prospective sequential acquisition.

Material and methods

We included 80 patients with heart rates ≤65 beats/min: 40 underwent sequential 128-slice single source CT with prospective synchronization and the other 40 underwent 128-slice dual source helical CT with high pitch and prospective synchronization. Two radiologists independently assessed the quality of the images of the coronary arteries on the 80 coronary CT angiograms: image quality was classified on a four-point scale in which 1 represented excellent and 4 deficient. The effective dose of radiation was also calculated.

Results

The clinical characteristics of the patients in the two groups were similar. The image quality obtained with dual source CT was significantly better than that obtained with single source CT (P=0.006). The mean effective dose of radiation in the group undergoing dual source CT was 36% lower than in the group undergoing single source CT (1.4±0.6 mSv vs. 2.2±0.9 mSv; P<0.01).

Conclusion

Although both sequential 128-slice single source CT with prospective acquisition and 128-slice dual source helical CT with high pitch and prospective acquisition provide good image quality and low effective doses of radiation, 128-slice dual source helical CT with prospective acquisition provides better image quality and results in a lower effective dose of radiation.     

Enterografía por resonancia magnética: técnica e indicaciones. Hallazgos en la enfermedad de Crohn

Radiology with oral contrast, or enteroclysis, have traditionally been the techniques of choice in the examination of the small intestine, due to the excellent visualisation of the mucosal pattern. However, the absence of extra-luminal information and the use of ionising radiation have replaced these examinations with sectional techniques which enable the abdominal cavity to be viewed with good resolution. Magnetic resonance enterography is a simple technique, with no ionising radiation, provided quality images, distends the intestinal lumen well by the administration of non-reabsorbable oral substances, minimises peristalsis, and establishes a protocol which includes sequences with intravenous contrast. These properties can be used in patients with Crohn's disease, achieving good diagnostic precision in the assessment of activity and monitoring of treatment, in intestinal obstruction, in the suspicion of small intestine tumours, and in paediatric patients due to it being harmless.     

Extravasación de medios de contraste intravenosos en el sitio de la punción: Protocolo de actuación

The incidence of contrast medium extravasation at the venipuncture site has increased with the generalized use of automatic injectors. Most extravasations only cause slight edema and erythema. Nevertheless, in some cases extravasation can result in severe skin lesions or even in compartment syndrome. Lesions caused by extravasation usually resolve spontaneously with conservative treatment. Although the complications of extravasation are well known, institutional protocols are normally lacking and the criteria for taking action and the type of treatment, whether based on the literature or personal preferences, tend to vary. In this article, we review the incidence, risk factors, clinical manifestations, and options for preventing and treating contrast medium extravasation in soft tissues. Finally, we present the protocol we use to manage extravasation at our hospital.     

Manifestaciones radiográficas de las atelectasias pulmonares lobares en la radiografía de tórax y su correlación con la tomografía computarizada

Atelectasis is an important indicator of potentially severe underlying disease that must be diagnosed as early as possible. One of the most common mechanisms is the reabsorption of air distal to respiratory tract obstruction. The chest X-ray is an excellent tool to diagnose atelectasis, and it is especially useful for ruling out central bronchial obstructions (e.g., from endobronchial tumors). If the signs of volume loss are not recognized correctly, the diagnosis and treatment can be delayed. This article describes the main findings of lobar atelectasis on chest X-rays and their correlations with CT findings, including the classic signs described in the literature and other, less known and sometimes subtle signs.     

Artritis idiopática juvenil,peculiaridades de la imagen en la edad pediátrica con especial interés en la resonancia magnética

The term juvenile idiopathic arthritis (JIA) encompasses a heterogeneous group of arthritides with no known cause that begin before the age of 16 years and persist for at least 6 weeks. In recent decades, imaging techniques have acquired a fundamental role in the diagnosis and follow-up of JIA, owing to the unification of the different criteria for classification, which has strengthened the research in this field, and to the development of disease-modifying antirheumatic drugs. In this article, we briefly explain what JIA is. Moreover, we describe the role and limitations of plain-film radiography, ultrasonography, and magnetic resonance imaging (MRI). Finally, we review the MRI protocol and findings, and we comment on the differential diagnosis.     

Neurografía de alta resolución del nervio peroneo en resonancia magnética 3T

Peroneal neuropathy is the most common mononeuropathy of the lower limbs. The causes of peroneal neuropathy include trauma, tumors of the nerve and nerve sheath, entrapment, and others like perineurioma, fibromatosis, lymphoma, and intraneural and externeural ganglia. The diagnosis is based on clinical manifestations and electrophysiological studies. Nowadays, however, magnetic resonance (MR) neurography is a complementary diagnostic technique that can help determine the location and cause of peroneal neuropathy. In this article, we describe the MR anatomy of the peroneal nerve, its relations, and the muscles it innervates. We also discuss the clinical and electrophysiological manifestations of peroneal neuropathy, describe the technical parameters used at our institution, and illustrate the MR appearance of various diseases that involve the peroneal nerve.     

Los patrones de vascularización pulmonar en la radiografía simple de tórax

Plain chest films are a fundamental tool in the practice of medicine. The apparent simplicity of plain chest films sometimes leads us to forget that interpreting them correctly can provide very valuable information, especially if the interpretation is grounded in key clinical information.     

La patología benigna de ano y recto con RM 3.0T. 2. 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.     

El esquema de biopsia transrectal puede predecir la gradación histológica incorrecta del cáncer de próstata

Objective

To identify factors that might explain why a prostate with a Gleason score (GS) <7 in the biopsy specimen can turn out to have a GS ≥7 in the surgical specimen.

Material and methods

We compared the GS of biopsy specimens with the GS of surgical specimens in 185 patients who underwent surgery for prostate cancer. We calculated the sensitivity, specificity, and predictive values for the GS of the biopsy specimens. We used Cohen's kappa to determine the degree of concordance between a GS of <7 and ≥7 for the biopsy specimen and the surgical specimen. Age, a family history of prostate cancer, total prostate-specific antigen (tPSA), digital rectal examination, prostate structure and volume, and the number of biopsy cores (biopsy scheme) were analyzed using multivariable logistic regression.

Results

Histological study of biopsy specimens yielded high sensitivity (98%) but low specificity (49%) for GS ≤6 and low sensitivity (35, 26%) and high specificity (93, 99%) for GS=7 and GS ≥7, respectively. Cohen's kappa for the GS from the biopsy and surgical specimens was 0.43 (95% CI=30-56%). The biopsy scheme was the only predictor of discordance in the GS between the two techniques. Among the other variables included in the model, only tPSA showed a slightly significant association. Taking a scheme with less than 7 cores as a reference, we found no difference with 8 to 9 cores but we did find a difference with 10 to 11 cores and with 12 or more cores, with a prevalence ratio of 0.138 (95% CI=0.030-0.513) and 0.277 (95% CI=0.091-0.806), respectively.

Conclusion

The GS of the biopsy depends on the scheme. This factor must be taken into account when choosing a treatment option in patients with low tumor grade in biopsy specimens.     

Síndrome de aorta media: presentación de tres casos pediátricos

The middle aortic syndrome (MAS) is caused by stenosis of the abdominal aorta, often accompanied by concomitant stenosis of the renal or visceral arteries. Although MAS is uncommon (0.5-2%), it is an important cause of hypertension in children and adolescents. It is thought to originate in a failure of the two dorsal aortas to fuse during embryological development, and a high percentage of cases are idiopathic. MAS affects the segment of the aorta between the renal arteries in 54% of cases. Clinically, it courses with symptomatic or asymptomatic arterial hypertension. On physical examination, findings include an abdominal bruit, diminished or absent femoral pulses, and a difference between the arterial pressure of the upper and lower limbs.     

Valoración radiológica de la hernia diafragmática congénita fetal

A diaphragmatic hernia is defined as the protrusion of abdominal viscera into the thoracic cavity through a normal or pathological orifice. The herniated viscera compress the lungs, resulting in pulmonary hypoplasia and secondary pulmonary hypertension, which are the leading causes of neonatal death in patients with congenital diaphragmatic hernia. Congenital diaphragmatic hernia is diagnosed by sonography in routine prenatal screening. Although magnetic resonance imaging is fundamentally used to determine whether the liver is located within the abdomen or has herniated into the thorax, it also can provide useful information about other herniated structures and the degree of pulmonary hypoplasia. The aim of this article is to review the fetal magnetic resonance findings for congenital diaphragmatic hernia and the signs that enable us to establish the neonatal prognosis when evaluating pulmonary hypoplasia.     

Energía dual y angioTC de carótidas: calidad,eliminación de hueso y dosis de radiación de 80/140 kV frente a 100/140 kV

Objective

To study the differences in vascular image quality, bone subtraction, and dose of radiation of dual energy CT angiography of the supraaortic trunks using different tube voltages.

Material and methods

We reviewed the CT angiograms of the supraaortic trunks in 46 patients acquired with a 128-slice dual source CT scanner using two voltage protocols (80/140 kV and 100/140 kV). The “head bone removal” tool was used for postprocessing. We divided the arteries into 15 segments. In each segment, we evaluated the image quality of the vessels and the effectiveness of bone removal in multiplanar reconstructions (MPR) and in maximum intensity projections (MIP) with each protocol, analyzing the trabecular and cortical bones separately. We also evaluated the dose of radiation received.

Results

Of the 46 patients, 13 were studied using 80/140 kV and 33 with 100/140 kV. There were no significant differences between the two groups in age or sex. Image quality in four segments was better in the group examined with 100/140 kV. Cortical bone removal in MPR and MIP and trabecular bone removal in MIP were also better in the group examined with 100/140 kV. The dose of radiation received was significantly higher in the group examined with 100/140 kV (1.16 mSv with 80/140 kV vs. 1.59 mSv with 100/140 kV).

Conclusion

Using 100/140 kV increases the dose of radiation but improves the quality of the study of arterial segments and bone subtraction.     

Revisión de aneurisma de aorta abdominal: hallazgos en la tomografía computarizada multidetector pre y postratamiento

The increase in the frequency of abdominal aortic aneurysms (AAA) and the widely accepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alternative to conventional surgery make it necessary for radiologists to have thorough knowledge of the pre- and post-treatment findings. The high image quality provided by multidetector computed tomography (MDCT) enables CT angiography to play a fundamental role in the study of AAA and in planning treatment.     

Los elementos decorativos ambientales en el Área de Imagen Médica mejoran la percepción de agradabilidad del paciente

Objectives

To evaluate the sensation of pleasantness perceived by patients attended in the radiology department in response to decorative elements hung on the walls in the waiting rooms and in the hallways of the imaging area.

Material and methods

The material resources comprised works of art in the form of “magic windows” representing scenes from nature installed on the ceilings and walls of the waiting area and hallways of the imaging area. Patients were given a brief questionnaire with general data and questions (sadness-cheerfulness, coldness-warmth, darkness-light, and pessimism-optimism) about their perception of the decorative elements.

Results

Of the 150 questionnaires collected, 142 were filled out correctly. The overall health of these patients was good in 84 (56%), not bad in 58 (39%), and poor in 8 (5%). The idea seemed very good to 70 patients (47%), good to 58 (39%), not bad to 8 (5%), indifferent to 11 (7%), bad to 1 (1%), and very bad to 2 (1%). As far a patients’ mobility, 119 patients (79%) walked into the department, 18 (12%) were wheeled in on beds, and 13 (9%) needed wheelchairs.

Conclusions

We found a high level of satisfaction with the decorative elements.