Genetic influences on brain structure.

Here we report on detailed three-dimensional maps revealing how brain structure is influenced by individual genetic differences. A genetic continuum was detected in which brain structure was increasingly similar in subjects with increasing genetic affinity. Genetic factors significantly influenced cortical structure in Broca's and Wernicke's language areas, as well as frontal brain regions (r2(MZ) > 0.8, p < 0.05). Preliminary correlations were performed suggesting that frontal gray matter differences may be linked to Spearman's g, which measures successful test performance across multiple cognitive domains (p < 0.05). These genetic brain maps reveal how genes determine individual differences, and may shed light on the heritability of cognitive and linguistic skills, as well as genetic liability for diseases that affect the human cortex.

Regional gray matter, white matter, and cerebrospinal fluid distributions in schizophrenic patients, their siblings, and controls.

BACKGROUND: Cortical gray matter volume reductions and cerebrospinal fluid (CSF) volume increases are robust correlates of schizophrenia, but their sources have not been established conclusively. METHODS: Structured diagnostic interviews and magnetic resonance imaging scans of the brain were obtained on 75 psychotic probands (63 with schizophrenia and 12 with schizoaffective disorder), ascertained so as to be representative of all such probands in a Helsinki, Finland, birth cohort; 60 of their nonpsychotic full siblings; and 56 demographically similar control subjects without a personal or family history of treated psychiatric morbidity. RESULTS: Patients with schizophrenia and their siblings exhibited significant reductions in cortical gray matter volume and significant increases in sulcal CSF volume compared with controls. The patients, but not their siblings, also exhibited significant reductions in white matter volume and significant increases in ventricular CSF volume. Regional effects were most robust when component volumes were expressed as percentages of overall regional volumes; in this case, for patient and sibling groups, gray matter volume reductions and sulcal CSF volume increases were significantly more pronounced in the frontal and temporal lobes than in the remainder of the brain. None of the group differences varied significantly by sex or hemisphere. CONCLUSIONS: Structural alterations of the cerebral cortex, particularly in the frontal and temporal lobes, are present in patients with schizophrenia and in some of their siblings without schizophrenia; such changes are thus likely to reflect genetic (or shared environmental) effects. Ventricular enlargement is unique to the clinical phenotype and is thus likely to be affected primarily by nonshared causative factors.

Amiodarone pulmonary toxicity. Chest radiography and CT in asymptomatic patients.

Two asymptomatic patients from a group of 30 being treated with the antiarrhythmic drug amiodarone developed roentgenographic pulmonary and pleural reactions. Computed tomography in one patient with an uncommon radiographic pattern of fuzzy nodules showed the spatial distribution of the parenchymal changes, as well as unrecognized pleural thickening. The disease in these asymptomatic patients was presumably detected on the periodic chest roentgenogram at an early stage because the changes disappeared after withdrawal of the drug. Periodic chest radiographs are recommended during amiodarone therapy and CT may be useful in evaluation of patients with unusual chest radiographic findings.

Contrast media-induced renal tubular vacuolization. A light and electron microscopic study on rat kidneys.

The morphologic changes in healthy rat kidneys (n = 102) were studied 2 or 48 hours after intravenous injection of 1 or 3 g iodine (I)/kg of high-osmolality diatrizoate, low-osmolality iopromide and iohexol, or iso-osmolality iotrolan, as well as after 0.2 or 0.6 g/kg of the high-osmolality magnetic resonance contrast medium gadolinium DTPA. Physiologic saline was injected in controls. The kidneys were fixed by perfusion and the specimens were analyzed semiquantitatively by two independent observers blinded to the treatment. A statistically significant (P less than .01) cytoplasmic vacuolization was noticed in the proximal convoluted tubule cells 2 hours after injection of 3 g I/kg of diatrizoate or iopromide. Iohexol and iotrolan induced an even more significant (P less than .01) and longer-lasting vacuolization, but gadolinium DTPA did not produce lysosomal alterations. Although the vital cell organelles remained intact, reversible lysosomal alterations may represent the first structural signs of a threatening cellular injury.

From objective to subjective: pitch representation in the human auditory cortex.

Magnetic brain responses to infrequent changes in the pitch of complex sounds were recorded. The composition of the test sounds required that pitch-deviant stimuli elicited the mismatch response only if perceived pitch was represented in auditory sensory memory. Results revealed that subjective features, such as pitch, are formed from objective stimulus parameters (i.e. the spectral contents of a sound) before storing acoustic information in memory. The origin of the magnetic response to pitch change showed that pitch deviation was detected in the auditory cortex. Pitch memory might also be located in the auditory cortex, as previous evidence suggests that storage for an auditory feature lies in the vicinity of the neuronal elements activated by deviations in that feature.

Delayed presentation of blunt splenic injury.

Eleven patients with delayed presentation of splenic injury after blunt abdominal trauma treated during a 10 year period have been described. They represented 24 percent of all patients treated for blunt splenic injury in our department in that time period. Ten patients required operative treatment and one was treated nonoperatively. There were no deaths. The value of computerized tomography and ultrasonography in the accurate preoperative assessment of splenic injury has been documented. In addition, the various diagnostic and therapeutic possibilities in blunt splenic trauma have been discussed.

Quantitative functional lung imaging with synchrotron radiation using inhaled xenon as contrast agent.

Small airways play a key role in the distribution of ventilation and in the matching of ventilation to perfusion. The purpose of this study was to introduce an imaging method that allows measurement of regional lung ventilation and evaluation of the function of airways with a small diameter. The experiments were performed at the Medical Beamline of the European Synchrotron Radiation Facility. Monochromatic synchrotron radiation beams were used to obtain quantitative respiration-gated images of lungs and airways in two anaesthetized and mechanically ventilated rabbits using inhaled stable xenon (Xe) gas as a contrast agent. Two simultaneous images were acquired at two different energies, above and below the K-edge of Xe. Logarithmic subtraction of the two images yields absolute Xe concentrations. This technique is known as K-edge subtraction (KES) radiography. Two-dimensional planar and CT images were obtained showing spatial distribution of Xe concentrations within the airspaces, as well as the dynamics of filling with Xe. Bronchi down to 1 mm in diameter were visible both in the subtraction radiographs and in tomographic images. Absolute concentrations of Xe gas were calculated within the tube carrying the inhaled gas mixture, small and large bronchi, and lung tissue. Local time constants of ventilation with Xe were obtained by following the evolution of gas concentration in sequential computed tomography images. The results of this first animal study indicate that KES imaging of lungs with Xe gas as a contrast agent has great potential in studies of the distribution of ventilation within the lungs and of airway function, including airways with a small diameter.

Multiphase segmented k-space velocity mapping in pulsatile flow waveforms.

The aim of the present study was to obtain the precision of flow measurement in breath-hold segmented k-space flow sequences. The results are based on studies of pulsatile flow in a phantom tube. The ultimate purpose is to use these sequences to measure coronary flow. In abdominal and cardiothoracic magnetic resonance imaging the image quality is degraded due to respiratory motion. In the segmented k-space acquisition method, one obtains many phase-encoding steps or views per cardiac phase. This shortens imaging time in the order of phase-encoding lines and makes it possible to image in a single breath-hold, thereby eliminating respiratory artefacts and improving edge detection. With breath-hold multiframe cine flow images it is possible to evaluate flow in all abdominal and cardiothoracic areas, including the coronary arteries. Our study shows that velocity curves shift in time when the number of k-space ky-lines per segment (LPS) are varied; this shift is linear as a function of LPS. The mean velocity Vmean in the center of mass of the pulsatile peak is constant (Vmean = 40.1 +/- 2.9 cm/s) and time t = -10.1 x LPS + 268 (r = 0.993, p < 0.0001). Correlation between theoretical and experimental flow curves is also linear as a function of LPS: C = -0.977 * LPS (r = 0.987, p < 0.0001). It is concluded that velocity curves move with LPS and are smoothed when the breath-hold velocity mapping is used. The more LPS is gathered the more inaccurate results are. LPS 7 or more cannot be considered clinically relevant.

Mammographic patterns in twin pairs discordant for breast cancer.

As part of a case-control study of breast cancer in pairs of twins selected from the population-based Finnish Twin Cohort, mammograms of 30 pairs (seven monozygotic (MZ), 23 dizygotic (DZ] discordant for breast cancer were analysed. The mammographic pattern in the unaffected breast of the cancer case was compared with the pattern in the ipsilateral breast of the healthy twin (control). There were no differences for MZ pairs, while among DZ pairs the cancer case had a prominent parenchymal pattern significantly more often than the control, as assessed by two radiologists independently and blindly. Thus, there is a relationship between parenchymal pattern and risk of breast cancer even when the controls are the twin sisters of breast-cancer cases and are themselves at high risk. The overall similarity, despite disease discordance, in parenchymal pattern of the twins (more evident among MZ than DZ pairs) suggests a familial, possibly genetic influence on parenchymal pattern.

Lobar liver anatomy. Definition by CT.

A method for identifying the physiological border between the hepatic lobes on an enhanced CT scan is described. The definition is based on combined information from the gall bladder fossa--vena cava line and the middle hepatic vein line.

Cinetracheobronchography and surgical correction of central airway collapse in an asthmatic patient.

The role of central airway collapse in asthma was demonstrated by cinetracheobronchography (CTBG) in a 45-year-old severely asthmatic woman, with total tracheal collapse during coughing. She was successfully treated by circumferential supportive tracheobronchial surgery, The contribution of CTBG in demonstrating tracheobronchial dynamics is stressed, not only in the pre-operative evaluation but also in the postoperative control.

Significance of extrapancreatic findings in computed tomography (CT) of acute pancreatitis.

Computed tomography (CT) has proven reliable in the early detection of acute haemorrhagic pancreatitis. In the present study the extrapancreatic changes at CT were studied in 60 patients with acute pancreatitis. The CT findings were correlated to the early "prognostic signs" by Ranson and the clinical course of the disease. All the patients with minor extrapancreatic changes recovered without complications. When moderate to severe extrapancreatic changes were seen the incidence of haemorrhagic pancreatitis and the risk of development of pseudocyst or abscess was high. In these patients a dynamic contrast enhanced CT should be done in order to select the patients with haemorrhagic pancreatitis.

Microangiography of the pancreas in experimental hemorrhagic pancreatitis.

In experimental hemorrhagic pancreatitis induced with sodium-taurocholate-trypsin, contrast enhancement of the pancreas in computed tomography (CT) has been shown to be decreased in spite of normal pancreatic blood flow. The contrast enhancement in CT depends on blood flow to the organ, capillary permeability and the amount of extracellular fluid in the organ. For further evaluation of the role of microcirculatory changes in our model of hemorrhagic pancreatitis, microangiography was performed in five normal piglets and in ten piglets with acute hemorrhagic pancreatitis. In this experimental model histological studies showed focal necroses, hemorrhages and leucocyte accumulation. In the affected areas microangiography revealed unfilled capillaries and extravasation of contrast medium. Arteries and arterioles were well filled, as in the normal control animals. These severe disturbances in the capillary circulation of the pancreas may explain the decreased contrast enhancement of the pancreas in CT during acute hemorrhagic pancreatitis.

Combination of multiple pencil-beam imaging to computed storage phosphor radiography: a new method.

Computed radiography (CR) with storage phosphors offers a wide dynamic range and improved sensitivity compared to film-screen technology. CR was combined in this study with a prototype multiple pencil-beam (MPB) imaging device which has been shown to be very effective in scatter reduction. The combination was analyzed and compared to the standard technique of grid screening in two ways: a free-response ROC (FROC) analysis was first performed followed by a blinded test arrangement for visual analysis of image quality in a series of computed radiography of the lumbar spine by both the MPB and grid modalities. The results of the FROC study showed a statistically significant (P less than or equal to 0.01) improvement in signal detection. The MPB-CR images of the lumbar spine had more contrast but also a slightly mottled or grainy appearance. Image quality was found good but contrast processing was criticized because it seemed to result in a too steep display of contrast in MPB imaging. This should be avoidable by changing the image processing parameters.

Dynamic fast-gradient echo MR imaging of pancreatic tumours.

The purpose of this study was to determine the diagnostic utility of dynamic magnetic resonance imaging (MRI) of the pancreas. Twenty-eight adult patients with known or suspected pancreatic tumours were examined. Pre- and post-gadolinium (GdDTPA-BMA) scans were obtained in combination with an oral negative contrast medium (ferristene) to mark the gastrointestinal tract. In 6 cases a more precise diagnosis could be made by dynamic MRI compared to unenhanced MRI. Surgery could confirm the MR diagnosis based on contrast enhancement in 83% compared to 78% for CT. The results of signal intensity (SI) measurements show that a combination of differences in baseline values before enhancement and the slope of enhancement within the first 20 s is a reliable criterion to distinguish between normal pancreas and hypovascular tumours. These tumours already show lower SI values before as well as lower slopes after early enhancement. Mainly two effects facilitate the final MRI diagnosis: (1) the delineation of the pancreas from the duodenum by the negative contrast medium, and (2) the enhancement pattern of pancreatic tumours by gadolinium-enhanced dynamic MRI compared to normal tissue within the early enhancement after contrast injection.

Milk-of-calcium renal cyst, evaluated by ultrasound and computed tomography.

Milk-of-calcium renal cysts, which when asymptomatic need no treatment, sometimes pose diagnostic problems by conventional radiography. Two such cases are here reported. The first case was further evaluated by ultrasonography only, the second case also by computed tomography and cyst puncture, because of an irregularity in the cyst wall. Both imaging modalities added valuable information.

Diagnostic value of ultrasound, computed tomography, and angiography in ruptured aortic aneurysms.

Some ruptural aneurysms cause nonspecific symptoms and the patients are referred for radiological examination because of the problems of differential diagnosis from conditions such as renal colic, diverticulitis, herniated disc, aortic dissection etc. Seven such patients have been examined either with ultrasonography, computed tomography or angiography. The diagnostic methods are compared. The more recent US and CT imaging methods are sufficiently rapid and reliable for diagnostic purposes, which should improve the prognosis for patients requiring immediate surgery for ruptured aortic aneurysms.

[Intravenous cholegraphy in acute cholecystitis (author's transl)]. / Die intravenöse Cholegraphie bei akuter Cholezystitis.

In this prospective study iv-cholegraphy was performed before surgery on 152 patients by whom acute cholecystitis could not be excluded. The examination was diagnostic in 85% of the cases. Most of the patients (20/23) with nonvisualization of the biliary tract by iv-cholegraphy suffered from acute cholecystitis, the others (3/23) from acute pancreatitis. In three false negative examinations the opacification of the gallbladder was weak and in three false positive cases the cystic duct obstruction was caused by a chronic gallbladder disease. Because the preliminary clinical suspicion of acute cholecystitis even when using rigid criteria proved to be false in 30% of the cases, we consider a radiologic clarification to be indicated. Iv-cholegraphy is found to be an important examination in acute cholecystitis, practicable even at small radiologic departments with conventional equipment, and a reliable indicator of cystic duct obstruction.

Pharmacokinetics of contrast medium in experimental pancreatography.

The pharmacokinetics of a contrast medium in experimental pancreatography of 17 piglets were studied by repeated radiographs of the pancreas and by measuring the concentration of I125-labelled CM in the portal vein, inferior vena cava and in the thoracic duct. Intraduodenal and portal vein injections were performed for comparison. Contrast enhancement of the pancreas after pancreatography was measured by CT. High concentrations of CM were seen in the portal vein 40 seconds after pancreatography, demonstrating direct absorption into the local veins. The concentration of CM in lymph exceeded the systemic concentration 15 minutes after injection, suggesting absorption into lymphatic vessels from the pancreas. CT revealed parenchymal filling of the pancreas even though no acinar filling was seen in normal radiographs. This suggests "invisible" parenchymal filling during normal pancreatography.

Vena cava umbrella filter: experimental, hemodynamic and embolization studies.

The Mobin-Uddin umbrella filter was placed into the inferior vena cava of mongrel dogs. Studies on hemodynamics and embolization were performed using blood flow and pressure determinations, cineangiography, and radiopaque emboli. Initially flow and pressure remained unaffected by the filter. At 70 minutes flow was only one fourth of the initial IVC flow. Immediately after positioning of the filter emboli up to 6 mm in diameter bypassed the filter, and smaller emboli passed through the perforations in the filter. Thrombus formation on the surface of the umbrella was already noted within one hour. At autopsy after two hours all the perforations were occluded by thrombus on both sides of the filter, and one week later the infrarenal vena cava was completely occluded by firm organized thrombus below and above the filter.