An elegant technique for ex vivo imaging in experimental research-Optical coherence tomography (OCT).

Optical coherence tomography (OCT) is an elegant technology for imaging of tissues and organs and has been established for clinical use for around a decade. Thus, it is used in vivo but can also serve as a valuable ex vivo imaging tool in experimental research. Here, a brief overview is given with a focus on an ex vivo application of OCT. Image and video examples of freshly obtained murine lungs are included. The main advantage of OCT for ex vivo analysis is the non-contact, non-invasive, and non-destructive fast acquisition of a three-dimensional data set with micrometer-resolution.

Does the stage 16 embryo in Hamburger-Hamilton's "Series of normal stages in the development of the chick embryo" have a potential "conotruncal" heart defect?

The classical Hamburger and Hamilton (HH) paper demonstrates the normal stages of development of the chick embryo that have been extensively used as the basis of understanding normal and abnormal development of the chick embryo heart. Careful examination of the series of images published in this seminal paper indicates that the cardiac images of stage 16 embryo shown in this article may reflect an abnormally developed heart. In this article, the argument is presented that the embryo depicted in the HH paper is not normal, but instead inflicted with a conotruncal heart defect.

Isolated noncompaction of the left ventricular myocardium -- a review of the literature two decades after the initial case description.

Isolated noncompaction of the left ventricular myocardium (INVM), first described in 1984, is an unclassified cardiomyopathy and is assumed to occur as an arrest of the compaction process during the normal development of the heart. Between weeks 5 to 8 of human fetal development, the ventricular myocardium undergoes gradual compaction with transformation of the relatively large intertrabecular spaces into capillaries while the residual spaces within the trabecular meshwork gradually flatten or disappear. In the case of INVM, the spaces within the intertrabecular meshwork persist while no other cardiac abnormalities exist. Although there is substantial evidence supporting the developmental hypothesis, other pathogenetic processes responsible for INVM have been discussed. It can be assumed that INVM will be better understood in the future as the molecular genetic basis of cardiomyopathies will be further unravelled. Echocardiography has been shown to be the method of choice in diagnosis of INVM. The diagnostic criteria can be summarized as: 1) appearance of at least four prominent trabeculations and deep intertrabecular recesses; 2) appearance of blood flow from the ventricular cavity into the intertrabecular recesses as visualized by color Doppler imaging; 3) the segments of noncompacted myocardium mainly involve the apex and the inferior mid and lateral mid of the left ventricular wall and typically show a two-layered structure with an endsystolic ratio greater than two between the noncompacted subendocardial layer and the compacted subepicardial layer; 4) absence of coexisting cardiac abnormalities. Magnetic resonance imaging using modern gradient echo sequences has also been shown to diagnose INVM accurately. The clinical presentation of INVM is characterized by a high prevalence of heart failure, thromboembolic events and arrhythmias including ventricular tachycardia and atrial fibrillation. The establishment of a registry, which was initiated by the "Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte (ALKK)" recently, may provide further clues for diagnosis, risk stratification, and management of this disease.

Pulmonary nodules: experimental and clinical studies at low-dose CT.

PURPOSE: To compare the number of pulmonary nodules detected at helical low- and standard-dose computed tomography (CT) and to investigate the diagnostic value of low-dose CT with a radiation exposure equivalent to that used at chest radiography. MATERIALS AND METHODS: Two radiologists recorded pulmonary nodules at standard-dose (250 or 100 mA, pitch of 1; 200 mA, pitch of 2) or low-dose CT (50 or 25 mA, pitch of 1 or 2) in five postmortem specimens and 75 patients. Nodules were assessed by size (5 mm or smaller, 6-10 mm, or larger than 10 mm) and by diagnostic confidence ("definite nodule," "definite lesion, not classic nodule," or "questionable lesion, possibly representing a vessel") with the Wilcoxon signed rank test. Artifacts depicted at low-dose CT were recorded. RESULTS: There were no statistically significant differences in the number of nodules detected at standard- or low-dose CT except in nodules 5 mm or smaller that were assessed as definite nodules at standard- or low-dose CT (25 mA, pitch of 2) (472 vs 397, P < .05). Artifacts that possibly interfered with nodule detection were observed exclusively at CT with 25 mA and a pitch of 2. CONCLUSION: Pulmonary nodules were detected reliably at CT with 50 mA and pitch of 2 or with 25 mA and a pitch of 1. However, further reduction of the dose to that used at chest radiography was associated with a significant decrease in the number of nodules 5 mm or smaller that were detected, possibly due to artifacts.

[Low dose computerized tomography of the thorax. Experimental and clinical studies]. / Niedrigdosiscomputertomographie des Thorax. Experimentelle und Klinische Untersuchungen.

INTRODUCTION: Computed tomography is a significant source of medical radiation exposure for populations in Europe. Reduced radiation exposure may be possible with modern CT scanners with an image quality that while less good than before remains acceptable for clinical purposes. The lung appears particularly well suited to investigation with low-dose CT owing to the high contrast between normal and diseased pulmonary parenchyma. METHODS: We analysed the diagnostic accuracy of different low-dose CT protocols for the detection of pulmonary nodules using inflation-fixed isolated postmortem lung specimens in a chest phantom. In a comparative patient study diagnostic accuracies of standard-dose CT (120 kV, 250 mAs; slice thickness 10 mm, pitch 1) and low-dose CT (120 or 140 kV, 50 mAs; slice thickness 5 or 10 mm, pitch 1 or 2) were assessed. RESULTS: Preliminary results suggest that low-dose CT protocols with radiation exposure of 10-20% of that with standard-dose CT an reliably depict soft tissue density pulmonary nodules with a diameter of more than 5 mm and can also demonstrate smaller nodules equally well is many cases. CONCLUSIONS: Low-dose CT may frequently be an adequate imaging procedure in a given clinical setting, particularly in young patients with benign disease.

Effect of increased wall thickness on indices of left ventricular pump function in children.

OBJECTIVE: To investigate whether augmented chamber performance in children with a concentric hypertrophied left ventricle is due to increased myocardial shortening or a geometric effect of the thickened ventricular wall. DESIGN: Chamber performance in terms of fractional area change and myocardial shortening--that is, circumferential midwall shortening--were measured by cross sectional echocardiography in young people with normal left ventricles and those with concentric hypertrophy of the left ventricle. PATIENTS: 52 healthy infants, children, and young people (age range 3 1/2 weeks to 26 years; body weight 1.8-89 kg (mean 23.6 kg)) and 29 infants, children, and adolescents with ventricular hypertrophy (mean body weight 31.4 kg, age range 4 weeks to 18.7 years). MAIN OUTCOME MEASURES: Chamber areas, fractional area change, midwall circumferential shortening normalised to body weight. RESULTS: In the controls normalised reference values were: end diastolic cavity area, 1.47 (0.25) cm2/kg0.65; fractional area change, 0.56 (0.03); end diastolic myocardial area, 1.62 (0.25) cm2/kg0.55; midwall circumferential shortening, 0.21 (0.03). By comparison, the patients had normal chamber areas (end diastolic myocardial area, 1.57 (0.42) cm2/kg0.65), increased fractional area change, 0.68 (0.05) (P < 0.001), and normal midwall circumferential shortening, 0.21 (0.03). There was a significant relation between the degree of hypertrophy (in terms of end diastolic myocardial area) and pump function while midwall shortening remained constant: 0.08 x end diastolic myocardial area + 0.44 (r = 0.74, P < 0.001). CONCLUSIONS: The relation between myocardial shortening, wall thickness, and fractional area change emphasises that the augmentation of pump function variables in left ventricular hypertrophy in young people is an effect of the thickened wall and not necessarily due to increased myocardial shortening. This relation offers the possibility of assessing the adequacy of chamber performance with respect to the degree of hypertrophy.