Morphometric variants of the paranasal sinuses in a Mexican population: expected changes according to age and gender.

BACKGROUND: There are developmental variations in the paranasal sinuses. Our objective was to determine their dimensions and volume stratified by age and sex and define the expected growth pattern. MATERIALS AND METHODS: A retrospective, observational study was performed including computed tomography (CT) of patients between 1 and 20 years of age. The volumes of the frontal, sphenoid, and maxillary sinuses were obtained. RESULTS: A total of 210 CT were included with a mean age of 10 ± 6.1 years, 106 (50.5%) were female. Groups were categorised in ranges of 5 years. Spearman correlation coefficients between the right and left sides were 0.843, 0.711, 0.916 for the frontal, sphenoid and maxillary sinuses. Post-hoc for the categorical age groups demonstrated statistically significant differences with values of p < 0.01, except between age groups 11-15 against ≥ 16 years of age (p = 0.8). Gender-related differences were evident with a higher air volume in girls in the 5-10-year-old group, while boys predominated in the rest of the groups. CONCLUSIONS: Computed tomography is ideal for pre-surgical sinus assessment. The maximum volume of paranasal sinuses is reached at the age of 15. There is a clear volumetric difference between age and gender groups. There is a direct relationship between a volume and its contralateral counterpart.

[Diffusion tensor imaging of the corticospinal pathway and its association with the prognosis of acute cerebral infarction: experience with a cohort in Mexico]. / Imagen del tensor de difusión de la vía corticoespinal y su asociación con el pronóstico del infarto cerebral agudo: experiencia de una cohorte en México.

INTRODUCTION: Magnetic resonance diffusion tensor imaging through the fraction of anisotropy allows evaluation of the integrity of the motor pathways after cerebral infarction. AIMS: To correlate the fraction of anisotropy with the clinical scales and the prognosis of cerebral infarction. SUBJECTS AND METHODS: Prospective study of patients with cerebral infarction to compare the fraction of anisotropy in different regions of interest with functional evaluations and with controls free of infarction. A subgroup of subjects with rehabilitation underwent an initial MRI scan and another at three months, with clinical follow-up for six months. RESULTS: Thirty-eight consecutive patients with middle cerebral artery infarction were included. The fraction of anisotropy values were lower in the ipsilateral corticospinal pathway than the fraction of anisotropy of the corticospinal pathway of the controls. The values of the fraction of anisotropy in the ipsilateral corticospinal pathway were associated with the value of the functional scale on admission. Changes in the fraction of anisotropy values between the initial MRI and the scan performed at three months correlated with the score on the functional scale and the modified Rankin scale at three and six months. CONCLUSIONS: The value of the fraction of anisotropy in the ipsilateral internal capsule is associated with the presence of a lesion and with its presenting symptoms. Changes in the fraction of anisotropy at three months suggest long-term clinical recovery.

TITLE: Imagen del tensor de difusión de la vía corticoespinal y su asociación con el pronóstico del infarto cerebral agudo: experiencia de una cohorte en México.Introducción. La imagen del tensor de difusión por resonancia magnética a través de la fracción de anisotropía permite evaluar la integridad de las vías motoras después de un infarto cerebral. Objetivo. Correlacionar la fracción de anisotropía con las escalas clínicas y el pronóstico del infarto cerebral. Sujetos y métodos. Estudio prospectivo de pacientes con infarto cerebral para comparar la fracción de anisotropía en diferentes regiones de interés con evaluaciones funcionales y con controles sin infarto. En un subgrupo con rehabilitación, se realizó una resonancia magnética inicial y a los tres meses, con un seguimiento clínico durante seis meses. Resultados. Se incluyó a 38 pacientes consecutivos con infarto cerebral de la arteria cerebral media. Los valores de la fracción de anisotropía fueron menores en la vía corticoespinal ipsilateral que en la vía corticoespinal de los controles. Los valores de la fracción de anisotropía en la vía corticoespinal ipsilateral se asociaron con el valor de la escala funcional en el momento de su admisión. Los cambios en los valores de la fracción de anisotropía entre la resonancia magnética inicial y a los tres meses se correlacionaron con la puntuación en la escala funcional y en la escala de Rankin modificada a los tres y a los seis meses. Conclusiones. El valor de la fracción de anisotropía en la cápsula interna ipsilateral se asocia a la presencia de lesión y a su presentación clínica. Los cambios en la fracción de anisotropía a los tres meses sugieren la recuperación clínica a largo plazo.

Comparison of Gadoterate Meglumine and Gadobutrol in the MRI Diagnosis of Primary Brain Tumors: A Double-Blind Randomized Controlled Intraindividual Crossover Study (the REMIND Study).

BACKGROUND AND PURPOSE: Effective management of patients with brain tumors depends on accurate detection and characterization of lesions. This study aimed to demonstrate the noninferiority of gadoterate meglumine versus gadobutrol for overall visualization and characterization of primary brain tumors. MATERIALS AND METHODS: This multicenter, double-blind, randomized, controlled intraindividual, crossover, noninferiority study included 279 patients. Both contrast agents (dose = 0.1 mmol/kg of body weight) were assessed with 2 identical MRIs at a time interval of 2-14 days. The primary end point was overall lesion visualization and characterization, scored independently by 3 off-site readers on a 4-point scale, ranging from "poor" to "excellent." Secondary end points were qualitative assessments (lesion border delineation, internal morphology, degree of contrast enhancement, diagnostic confidence), quantitative measurements (signal intensity), and safety (adverse events). All qualitative assessments were also performed on-site. RESULTS: For all 3 readers, images of most patients (>90%) were scored good or excellent for overall lesion visualization and characterization with either contrast agent; and the noninferiority of gadoterate meglumine versus gadobutrol was statistically demonstrated. No significant differences were observed between the 2 contrast agents regarding qualitative end points despite quantitative mean lesion percentage enhancement being higher with gadobutrol (P < .001). Diagnostic confidence was high/excellent for all readers in >81% of the patients with both contrast agents. Similar percentages of patients with adverse events related to the contrast agents were observed with gadoterate meglumine (7.8%) and gadobutrol (7.3%), mainly injection site pain. CONCLUSIONS: The noninferiority of gadoterate meglumine versus gadobutrol for overall visualization and characterization of primary brain tumors was demonstrated.

Thyroid nodules in Hispanic patients with systemic lupus erythematosus.

A thyroid nodule (TN) is a discrete lesion in the thyroid gland radiologically distinct from the adjacent parenchyma, with a prevalence variable depending on the diagnostic method used and the study population. Thyroid disorders have been identified in more than 50% of patients with systemic lupus erythematosus (SLE); however, the prevalence of TN has not been frequently studied. We identified a prevalence of 27% TN in 55 SLE patients > 16 years of age. One-third of TN were >1 cm with radiological features of malignancy. The mean age of patients with TN was 39 ± 11 years, 93% women, and SLE duration 10 ± 6 years. Among patients, we reported family history of cancer in three cases (20%), thyroid disease in one (7%), and autoimmune disease in six (40%). Regarding treatment, 50% of patients with TN were treated with azathioprine vs. 23% of patients without TN (p = 0.02), with an OR of 3.94 (95% CI 1.12-13.84, p = 0.03). As a conclusion a high prevalence of TN in SLE patients was found. Prevalence of TN correlated only with history of azathioprine use. We don't know the long-term implications of our findings; however, a functional and morphological evaluation of the thyroid gland is warranted in all patients with SLE.

Intraprostatic distribution and long-term follow-up after AdV-tk immunotherapy as neoadjuvant to surgery in patients with prostate cancer.

A phase I-II study to evaluate gene-mediated cytotoxic immunotherapy in newly diagnosed prostate cancer before radical prostatectomy was conducted in Monterrey, Mexico. First, to investigate delivery of adenovirus to the prostate, fluorescently labeled vector was injected into fresh prostatectomy specimens and distribution was visually analyzed. The optimal volume and site instillation was then used for transrectal ultrasound guided intraprostatic injection in 10 patients with adenocarcinoma scheduled for radical prostatectomy. Each received two apical and two basal 0.5 ml injections of AdV-tk for a total of 1 × 10(11) vp followed by 14 days of prodrug. Nine patients continued to tumor resection: six high risk, one intermediate and two low risk. In vivo vector distribution was analyzed from the resected tissue of four patients. Patients were monitored for tumor progression and acute and long-term safety. For vector delivery, two apical and two basal injections of 0.5 ml led to optimal organ-wide distribution ex vivo and in vivo. Cytotoxicity was evidenced by transient rise in PSA and tumor histology. There were no significant adverse events deemed related to the treatment and no late toxicities after median follow-up of 11.3 years. All six high-risk patients had positive surgical margins and one had seminal vesicle involvement. Despite slow PSA rise post surgery in three of these patients, none developed metastases. The intermediate- and low-risk patients had complete resections and none have progressed. In conclusion, in vivo transrectal ultrasound guided instillation of an adenoviral vector into four sites in the prostate was practical as an outpatient procedure, well tolerated and led to distribution throughout the intraprostatic tumor mass. AdV-tk demonstrated no significant acute or late toxicities. Trends in PSA and disease progression conveyed the possibility of a sustained immune response against residual disease.

[Vertebral fixation with a transpedicular approach. Relevance of anatomical and imaging studies]. / Fijación vertebral por vía transpedicular. Importancia de los estudios anatómicos y de imagen.

The number of patients with spine conditions has grown exponentially in recent years leading to an increase in the number of cases requiring surgical treatment. Currently vertebral fusion surgery with a transpedicular approach represents the most commonly used technique to treat any type of vertebral disorder. The morphometric characteristics of vertebrae, particularly the pedicle, determine the size of pedicular implants, including width and length, as well as the shape and direction of the screw and its ideal angulation at the time of introduction. Knowing these characteristics is important to prevent injuring important adjacent structures and to decrease the postoperative complication rate. In recent decades numerous studies on the morphometric characteristics of the vertebral pedicle have been conducted in different populations to determine its real dimensions by means of direct measurement and imaging methods. These studies have concluded that there are significant differences in these measurements among the different ethnic groups, races, genders, ages and the vertebral regions studied. This paper analyzes the different morphometric studies of the pedicle and all the other vertebral elements studied in Mexico and the rest of the world and explain the importance of their knowledge and surgical application for the correct development of vertebral fusion surgery with a transpedicular approach.

Characterization of skeletal muscles by MR imaging and relaxation times.

Magnetic resonance (MR) images of three major flight muscles of chicks were obtained with surface coils using a 0.3 Tesla whole body imaging system (FONAR Beta 3000). The two fast muscles, pectoralis major (PM) and posterior latissimus dorsi (PLD), and a slow muscle, anterior latissimus dorsi (ALD), were identified in the axial, coronal, and sagittal images. The signal intensity (SI) of each muscle was electronically measured and its ratio to the background noise (S/N) was determined. Although visually the three muscles showed intermediate SI, the slow and fast muscles could be differentiated on the basis of their S/N values. These values were invariably higher in the slow muscles than in the fast muscles. To understand these differences, the muscles were excised and their mono- and multiexponential MR relaxation times (T1 and T2) were determined at 30 MHz. Multiexponential analysis enhanced the differences between the muscle types. With the sole exception of short T2, all relaxation components of the slow muscles were significantly longer than those of the fast muscles. These results suggest that elevation in the S/N, T1 and T2 values of muscles may not necessarily indicate a pathologic event, but may reflect the preponderance of slow fibers.

Enhanced T1 differentiation between normal and dystrophic muscles.

Proton spin-lattice relaxation times (T1) of pectoralis major muscles from normal (Line 412) and homozygous dystrophic (Line 413) chicks was measured by FONAR QED 80 at 1.69 MHz. The T1 values of dystrophic muscles (216.8 +/- 17.3 ms) was two-fold higher than those of normal muscles (110.2 +/- 8.1 msec). When these values were compared with the T1 values obtained at high frequencies (20 MHz and 32 MHz), the T1 differentiation between normal and dystrophic muscles was considerably enhanced at 1.69 MHz. Based on these results, we suggest that the high resolution of T1 obtained at low frequency (1.69 MHz) could be effectively used to detect the degenerative processes in muscles by the NMR techniques.