Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.     

Renal function and effective beta-blockade in cirrhosis with ascites. Relationship with baseline sympathoadrenergic tone

Renal function, plasma norepinephrine, renin activity (PRA) and aldosterone were determined in 17 cirrhotics with ascites, before and after effective beta-blockade (resting heart rate reduction greater than or equal to 20%) induced by oral propranolol. The drug lowered PRA (from 2.86 +/- 0.96 (S.E.) to 1.86 +/- 0.7 ng/ml/h; P less than 0.005) and plasma aldosterone (from 309.0 +/- 59.2 to 202.6 +/- 26.7 pg/ml; P less than 0.005). As expected, plasma norepinephrine (PNC) increased from 90.7 +/- 12.2 to 176.8 +/- 43 ng/l (P less than 0.01) in the 10 patients with normal basal values ('normal-PNC' group), but it decreased in 6 of the 7 patients with basal sympathoadrenergic hypertone ('high-PNC' group; mean value from 352.6 +/- 37.8 to 273 +/- 39.3 ng/ml (P = 0.06). Glomerular filtration rate and filtered sodium load did not change in the group as a whole and in 'normal-PNC' cirrhotics (from 83.2 +/- 7.1 to 81.4 +/- 7.8 ml/min, and from 11.63 +/- 0.96 to 11.45 +/- 1.14 mmol/min), but rose in 'high-PNC' patients (from 60.7 +/- 9.1 to 109.3 +/- 27.2 ml/min, and from 8.39 +/- 1.31 to 15.47 +/- 3.95 mmol/min; P less than 0.05). Renal sodium excretion increased from 2.45 +/- 0.75 to 3.16 +/- 1.01 mmol/h (P less than 0.01) in the group as a whole. Such an increase, however, was confined to 'high-PNC' cirrhotics. In this group, the tubular rejection fraction did not change and post-beta-blockade sodium excretion was correlated with the filtered sodium load (Rs = 0.83; P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)     

Did Columbus Also Open the Exploration of the Modern Diet?

On the 500th anniversary of Columbus's voyage of discovery, one aspect that merits particular attention is its influence on food and nutrition worldwide. Columbus found an unexpected wealth in food resources rather than the gold he sought. The sailors came from a continent where famine was well known and had subsisted for two months on a typical seamen's diet of preserved foods, primarily hardtack and salt pork. They made landfall in green and fertile islands. The foods that constituted the core of the diet of the Americas before 1492--from maize to potatoes, beans to tomatoes, to numerous other fruits and vegetables--became the true patrimony that the inhabitants of the New World bequeathed to humanity. These foods, new to the Old World, provided the basis for the exchange and evolution of networks of food production and consumption which, with many trials and errors and with no preestablished plan, characterize modern nutrition. The diet of Mediterranean countries, now universally recommended for nutritional health, is high in several foods, tomatoes and beans in particular, that originated in the New World.     

A case of primary malignant hemangiopericytoma of the heart with fatal outcome

Hemangiopericytoma is a rare, highly vascular tumor which has both malignant and benign varieties. We report a case of a 41-year-old man who underwent surgery in emergency because of cardiac tamponade. The histopathologic examination of the specimens revealed primary malignant cardiac hemangiopericytoma. The patient died 46 days from the beginning of symptoms and 13 days after surgery.     

Clinical indications for cardiac computed tomography. From the Working Group of the Cardiac Radiology Section of the Italian Society of Medical Radiology (SIRM)

Cardiac computed tomography (CCT) has grown as a useful means in different clinical contexts. Technological development has progressively extended the indications for CCT while reducing the required radiation dose. Even today there is little documentation from the main international scientific societies describing the proper use and clinical indications of CCT; in particular, there are no complete guidelines. This document reflects the position of the Working Group of the Cardiac Radiology Section of the Italian Society of Radiology concerning the indications for CCT.     

In vivo 3 T MR diffusion tensor imaging for detection of the fibre architecture of the human uterus: a feasibility and quantitative study

Objective

The aim of this study was to investigate the feasibility of depicting fibre architecture of human uteri in vivo using 3 T MR diffusion tensor imaging (MR-DTI) with a three-dimensional (3D) tractography approach. Quantitative results were provided.

Methods

In vivo 3 T MR-DTI was performed on 30 volunteers (9 Caesarean delivery). Main diffusion directions reflecting the fibre orientation were determined using sensitivity-encoding single-shot echo planar imaging with diffusion-sensitised gradients (b=600 mm² s⁻¹) along 32 directions. A deterministic fibre-tracking algorithm was used to show in vivo fibre architecture, compared with ex vivo histological slides of cadaveric uteri. The number of fibres, the fibre density, the fractional anisotropy (FA) and the apparent diffusion coefficient (ADC) were measured in 13 volunteers.

Results

Anisotropy was found in most regions of normal uteri and the preferential order of uterine fibres depicted, consisting of two representative fibre directions: circular and longitudinal, as in ex vivo studies. Two-thirds of uteri with a Caesarean scar did not have the same orientation of fibres in the anterior isthmus when compared with non-scarred myometrium. Quantitative data were obtained from 13 volunteers: Caesarean-scarred uteri (n=5) showed lower fibre number and density in the scarred anterior isthmus than the nulliparous uteri (n=8). No significant differences were found in FA (0.42±0.02, 0.41±0.02; p=0.25) and ADC (1.82±0.18×10⁻³ mm² s⁻¹, 1.93±0.25×10⁻³ mm² s⁻¹; p=0.20).

Conclusion

Fibre architecture of the human uterus can be depicted in vivo using 3 T MR-DTI.

Advances in knowledge

3 T MR-DTI can help to provide an in vivo insight of uterine anatomy non-invasively, especially in females with previous Caesarean surgery, in order to provide better management of subsequent deliveries.The human uterus is a fibromuscular organ composed of three layers: the endometrium (the innermost mucosal layer, lining the uterine cavity), the myometrium (the middle layer, consisting of smooth muscle bundles and connective tissue) and the perimetrium (the outer layer, corresponding to the peritoneum). The overall arrangement of muscle fibres in the human uterus has been extensively investigated [1], showing that the uterine wall consists of two counter-rotating systems of spiral fibres. Fibres in the myometrium are divided into the internal layer (stratum subvascolare), which mostly run in a circular pattern, and the external layer (stratum supravascolare), which mostly run in a longitudinal pattern. There is also an intermediate layer (stratum vascolare) in which the fibres run in random directions.Research has led to constant advancements in MR hardware and software. One such example is the evolution of diffusion tensor imaging from diffusion-weighted imaging [2,3]. MR diffusion tensor imaging (MR-DTI) is an emerging non-invasive method to determine the amount of random diffusion (Brownian motion) of water molecules in tissues, providing physiological information about the mobility of water that aids in tissue characterisation. The technique works by assuming water molecules will diffuse in the same direction as the general orientation of the fibres rather than perpendicular to them. Anisotropy can be quantified by calculating the diffusion tensor, which depicts the preferential water movement using multiple diffusion-weighted acquisitions with directionally varying diffusion sensitisation gradients. Another recent advancement is in the collaborative use of MR-DTI and fibre tractography. Fibre tractography is a novel software application that estimates the tensor value of each voxel to obtain the direction of fibres in a three-dimensional (3D) image, starting from the water diffusion profile in each voxel. It works by depicting the intervoxel connectivity based on the anisotropic diffusion of water to give quantitative information on the dominant direction of the water in a well-organised tissue.The MR-DTI with 3D fibre tractography approach has been successfully applied to the analysis of neuronal pathways in the brain in vivo [4], but there are few studies that do not concern neuronal applications. There have been several MR-DTI feasibility studies in animals showing the anatomical fibre distribution in skeletal muscle, tongue and heart [5-7]. There have also been some studies on in vivo human skeletal muscle [8,9], tongue [10] and ventricular myocardium [11]. There is only one study on the uterus using MR-DTI, which was performed ex vivo on patients subjected to a hysterectomy for medical reasons [12]. They demonstrated that uterine muscle fibre direction or anisotropy can be estimated because water molecules diffuse more easily along the muscle fibres than across them, highlighting the extremely structured muscular tissue. The method was validated against histological slides and depicted two systems of fibres running circularly along the intramural part of the uterine tubes, indicating that MR-DTI is a beneficial and complementary tool to standard microscopic techniques to determine the intrinsic fibre architecture [12].We hypothesise that if such a well-organised structure is in any way altered, for example by Caesarean surgery, the fibre architecture will show some degree of disarray.Caesarean deliveries are still increasing in Western society, often due to medicolegal reasons [13]. The incidence of placenta previa and/or placenta accrete in females with previous Caesarean section is much higher than in females with normal deliveries. As a consequence, there has also been a rise in the number of abnormal placental insertions, which are the major causes of mortality or hysterectomy due to post-partum haemorrhage complications [14,15]. This suggests that the structural architecture of the uterus altered by Caesarean surgery could predispose the development of placental abnormalities in subsequent pregnancies.The first purpose of the study was to verify the feasibility of using a 3 T MR-DTI with a 3D tractography approach in depicting fibre architecture of the uterus in vivo. The secondary aim was to compare the fibre architecture of non-scarred uteri with Caesarean-scarred uteri in vivo. Furthermore, preliminary data using 3 T MR-DTI are shown regarding the number of fibres, the fibre density, the fractional anisotropy (FA) and the apparent diffusion coefficient (ADC).     

Chemical synthesis and in vitro biocompatibility tests of poly (L-lactic acid)

Polylactic acid is a polymer of great technological interest, whose excellent mechanical properties, thermal plasticity, and bioresorbability render it potentially useful for environmental applications, as a biodegradable plastic and as a biocompatible material in biomedicine. This article discusses the synthesis and characterization of poly-L-lactic acid, obtained through two synthetic routes: direct polycondensation reactions without organic solvents, and in a supercritical medium. Tin complexes were used as catalysts in both polymerization reactions. The polymers were characterized by (1)HNMR, IR, GPC, DSC, and TGA techniques. In vitro biocompatibility tests were performed with human alveolar bone osteoblasts and there were assessed cell adhesion, proliferation and viability. The poly condensation reaction proved to be an excellent synthetic route to produce PLA polymers with different molar mass. The formation of polymers from lactic acid monomer was confirmed through techniques utilized. It was observed that cell adhesion and viability was not disturbed by the presence of the polymer, although the proliferation rate was decreased when compared to control.     

Role of carcinoembryonic antigen, magnetic resonance imaging, and positron emission tomography-computed tomography in the evaluation of patients with suspected local recurrence of colorectal cancer

The role of carcinoembryonic antigen (CEA), magnetic resonance imaging (MRI), and positron emission tomography (PET)-computed tomography (CT) in detection of local recurrence of colorectal cancer is evaluated in 71 patients, selected due to suspected relapse at CT follow-up. Recurrence was confirmed by histology in 18 cases and excluded in 25 cases. Sensitivity, specificity, positive and negative predictive values, and accuracy were as follows: 44.4%, 92.5%, 66.7%, 83.1%, and 80.3% for CEA; 88.9%, 73.6%, 53.3%, 95.1%, and 77.5% for MRI; and 94.4%, 73.6%, 54.8%, 97.5%, and 78.9% for PET-CT. A diagnostic protocol integrating CEA and dedicated imaging studies is to be advocated.