Computer-assisted analysis of wall motion of the right ventricle in a normal patient sample and diagnosis of right heart infarction using transesophageal echocardiography

Using 2D and M-Mode transesophageal short axis cross sections, right ventricular systolic wall motion was quantified in 15 normal patients. A further group of 39 patients with right ventricular infarction was investigated. In the normal group fractional shortening of the septum was -19.6% (-45 to 8%), that of the lateral wall 51.6% (37 to 73%), of the posterior wall 33.9% (5 to 50%) and of the anterior wall 42.7% (18 to 57%). Right ventricular infarction (RVI) was associated in 33 patients with posterior left ventricular infarction (85%) and in three patients with anterior infarction. In two cases only an isolated RVI was found. Right ventricular dilation occurred in 24 patients (61%). Hemodynamic criteria were fulfilled in eleven out of 21 patients (53%). RVI was confirmed in one patient by surgery and in ten patients by autopsy. Recognition of regional wall motion abnormalities by transesophageal echocardiography permits an accurate bedside identification of RVI. 2D and M-Mode registration of the short axis improves RVI assessment. Wall motion analyses offer the possibility to determine the extent of right ventricular infarction.     

Diffusion limitation and limitation by chemical reactions during alveolar-capillary transfer of oxygen-labeled CO2

A major difficulty in the measurement of carbon dioxide diffusing capacity is the development of significant CO2 back pressure within the capillary. The use of oxygen-labeled CO2 limits this back pressure due to rapid dilution of the label into the water pool by isotopic exchange. We demonstrated the use of C16O18O to measure DCO2 (Schuster, 1985). A major question from that study is whether the isotope measures a true membrane diffusing capacity or is limited by back reaction. In this study we examine the diffusing capacity of doubly 18O-labeled carbon dioxide, C18O2, a species in which the kinetics of isotopic exchange in pulmonary blood is higher than that of C16O18O. Eighteen single breath experiments were performed on two resting male subjects whose CO2-transfer-kinetics was previously studied with C16O18O (Schuster, 1985). Following expiration to residual volume the subjects inspired a gas mixture containing 20% O2 and 1.5-2.6% C18O2. After holding their breath for 0.4-17 sec they exhaled into a tube and the end-expired gas was analysed by mass spectrometry. The time course of the C18O2 disappearance from alveolar gas showed a biexponential characteristic as that which had been measured with C16O18O, but C18O2 disappeared faster. The mean value of the diffusing capacity of C18O2 amounts to 1102 ml mmHg-1 X min-1. It is 228 +/- 163 ml mmHg-1 X min-1 greater than that of C16O18O. This significant difference suggests that: DC16O18O is limited in part by isotopic exchange reactions; the observed DC18O2 may be taken as a new lower limit for DMCO2, higher than values established from other techniques; the decarboxylation of bicarbonate in red cells is not a rate limiting step for CO2 exchange.     

Objective tissue differentiation in sonography using local texture analysis

An approach to differentiating tissues by means of local texture analysis is described and its diagnostic power is evaluated using various diseases of the liver, kidney and the prostate.     

MR of esthesioneuroblastoma (olfactory neuroblastoma) and appearance after craniofacial resection.

PURPOSETo analyze the MR characteristics of a series of patients with esthesioneuroblastoma and discuss the typical surgery and its postoperative MR appearance.METHODSThe MR studies of 15 patients with the pathologic diagnosis of esthesioneuroblastoma (also known as olfactory neuroblastoma) were retrospectively reviewed and correlated with CT and surgical findings. The postoperative MR studies of 10 patients who underwent craniofacial resection were also reviewed.RESULTSIn all cases the tumors arose in the superior nasal cavity and extended into the ethmoid cells. In some instances the tumors extended into the other paranasal sinuses, orbits, anterior cranial fossa, and cavernous sinus. The tumors were typically expansile and destructive in their growth patterns. Compared with brain gray matter, the tumors were hypointense on T1-weighted images and isointense to hyperintense on T2-weighted images. Nine tumors were heterogeneous and 6 were homogeneous. Contrast enhancement ranged from mild to marked. MR was useful for characterizing the various tissues and distinguishing fluid in the postoperative nasal cavity.CONCLUSIONSEsthesioneuroblastoma, although an uncommon tumor, may be suspected in lesions of the superior nasal cavity demonstrating both expansile and destructive growth properties. The MR findings are otherwise nonspecific. MR is the imaging modality of choice for depicting local tumor extension and evaluating for recurrence after craniofacial resection.     

Bilocular atrial malignant mesenchymoma causing mitral and localized pulmonary vein flow obstruction: diagnosis by transoesophageal echocardiography.

Cardiac malignant mesenchymoma is an extremely rare malignancy with poor prognosis. We report a patient presenting with a history and clinical findings typical of mitral stenosis. Transthoracic echocardiography showed a mass on the thickened posterior mitral leaflet. Transoesophageal echocardiography revealed two tumoural masses: one on the atrial side of the posterior mitral leaflet causing mitral obstruction, the other arising in the region of the right lower pulmonary vein orifice and obstructing inflow through this vein.