Virtual colonoscopy: imaging features with colonoscopic correlation

BACKGROUND: We determined whether activation of the nitric oxide/cyclic guanosine monophosphate pathway by sodium nitroprusside (SNP) protects hearts subjected to cardioplegic arrest and prolonged hypothermic storage. METHODS: Isolated rat hearts arrested with St. Thomas' II cardioplegia and stored at 3 degrees +/- 1 degree C for 8 hours were reperfused at 37 degrees C in Langendorff (10 minutes) and working (60 minutes) modes. RESULTS: During reperfusion, left ventricular work was depressed in stored hearts relative to fresh hearts. When present during arrest, storage, and both reperfusion phases, SNP (200 mumol/L) improved work to values close to those in fresh hearts. When added only during the 10-minute period of Langendorff reperfusion, SNP also improved the subsequent recovery of work. This effect was antagonized by the soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Poststorage coronary perfusion was not increased by SNP. CONCLUSIONS: The ability of SNP to enhance recovery independent of changes in coronary perfusion and in an ODQ-sensitive manner suggests that SNP-induced protection is due to activation of the myocardial nitric oxide/cyclic guanisine monophosphate pathway. These results suggest that supplementing cardioplegic solutions with SNP, administering SNP during early reperfusion, or both may offer additional means to improve donor heart preservation.     

Quantitative evaluation of flow patterns in perfusion cannulae by a new magnetic resonance imaging method

The arterial cannula is a critical part of any extracorporeal circulation system due to the high flow rates which must pass a small cross-sectional area, resulting in high blood velocities. The aim of this study was to examine whether high-field magnetic resonance scanning is applicable for detailed mapping of velocity fields around the tip of such arterial cannulae in vitro. The investigated cannula was an angled, open-tip traditional design aortic cannula with an internal tip diameter of 5.5 mm. The velocity fields were measured at two different flow rates (2 and 4 l/min) at various positions in the lumen and outside the cannula using magnetic resonance imaging (MRI). All three components of the velocity vectors were measured. The study showed that MRI can provide a clear quantitative visualization of the velocity field around the tip of arterial cannulae at lower flow rates. At higher flow rates it can provide information about localization of regions with turbulent or disturbed flow.     

Encephalocoele as a complication of intranasal sinus surgery: optimal evaluation with magnetic resonance imaging

We report a case of post-operative frontal basal encephalocoele evaluated using a new magnetic resonance imaging (MRI) sequence, fast inversion recovery for myelin suppression (FIRMS). FIRMS was developed to enhance the differentiation between grey and white matter. In this case, the sequence was beneficial in distinguishing the encephalocoele from adjacent nasal mucosa and secretions.     

Blount''s disease: magnetic resonance imaging

He often begins to answer before you have finished asking your question, but his replies are to the point. He speaks with emotion about the people he hopes to help, particularly children with fatal genetic diseases. 'I prefer to do something: the outcome of doing nothing is perfectly clear', he says. He began sequencing human genes while others were discussing how and when to do so. His methods have been called inelegant, redundant, wasteful, and too 'industrial'. Will his method fail to detect some infrequently transcribed genes? That's all right with him. He is not concerned with finding all the human genes, but rather with the fastest possible route to a useful catalog of most human genes.     

Endodermal sinus tumor of the vagina in an infant: magnetic resonance imaging evaluation

Endodermal sinus tumor is a rare and highly malignant lesion. This report documents the clinical findings and magnetic resonance imaging (MRI) of an uncommon case of the endodermal sinus tumor arising in the vagina of a 6-month-old infant. MRI was extremely accurate in delineating the possible extent and location of the vaginal lesion. This is the first report to demonstrate MRI of vaginal endodermal sinus tumor.     

Advances in magnetic resonance imaging: applications in body imaging

Recent developments in the field of endocrine cell biology and pathology at both morphological and molecular levels are briefly outlined and discussed as a basis for endocrine tumor characterization. The main tools available for identifying the endocrine nature of the tumors, their pathogenetic interpretation. and experimental reproduction with special emphasis on tumor antecedents are reported. Based on this, classifications of endocrine tumors of the pancreas and gastrointestinal tract are developed, covering most clinical (hyperfunctional syndromes included), pathological, and biological patterns, with special emphasis on tumor prognosis.     

Serendipity in diagnostic imaging: magnetic resonance imaging of the breast

BACKGROUND: Magnetic resonance imaging (MRI) of the breast has been proposed as a noninvasive diagnostic test for evaluation of suspicious ("index") lesions noted on mammography and/or clinical breast examination (CBE). However, women may have incidental ("serendipitous") lesions detected by MRI that are not found on mammography or CBE. To understand better whether or not biopsy procedures should be performed to evaluate serendipitous lesions, we estimated the breast cancer risk for women with this type of lesion. METHODS: A decision analysis model was used to estimate the positive predictive value (i.e., the chance that a woman with a serendipitous lesion has cancer) of MRI for serendipitous lesions in women who had an abnormal mammogram and/or CBE suspicious for cancer (where a biopsy procedure is recommended). We restricted the analysis to data from women whose index lesions were noncancerous and used meta-analysis of published medical literature to determine the likelihood ratios (measures of how test results change the probability of having cancer) for MRI and the combination of CBE and mammography. The positive predictive value of MRI was calculated using the U.S. population prevalence of cancer (derived from registry data) and the likelihood ratios of the diagnostic tests. RESULTS: Under a wide variety of assumptions, the positive predictive value of MRI was extremely low for serendipitous lesions. For instance, assuming sensitivity and specificity values for MRI of 95.6% and 68.6%, respectively, approximately four of 1000 55- to 59-year-old women with serendipitous lesions would be expected to have cancer (positive predictive value = 0.44%, 95% confidence interval = 0.24%-0.67%). CONCLUSION: In women with a suspicious lesion discovered by mammography and/or CBE that is found to be benign, serendipitous breast lesions detected by MRI are extremely unlikely to represent invasive breast cancer. Immediate biopsy of such serendipitous lesions may, therefore, not be required.     

Functional evaluation using magnetic resonance imaging of the visual cortex in patients with retrochiasmatic lesions

OBJECT: The goal of this study was to evaluate the clinical potential of combining functional magnetic resonance (fMR) imaging with conventional morphological MR imaging and to assess its usefulness for objective evaluation of visual function as part of treatment planning in patients harboring space-occupying lesions involving the posterior afferent visual system. METHODS: It was hypothesized that regional activation of the visual cortex during visual stimulation would show an asymmetric response consistent with the well-known retinotopical organization of the human visual cortex. To test this hypothesis, the pattern of regional cortical activity detected by fMR imaging during binocular repetitive photic stimulation (10 Hz) was compared with the findings of conventional visual field testing. Functional mapping of the visual cortex was performed using a noninvasive blood oxygen level-dependent MR technique in 10 patients with intraaxial and two with extraaxial lesions. Experiments involving two of the patients were unsuccessful because of motion artifacts. In all the remaining patients functional activity was demonstrated in the primary visual area that corresponded to the anatomical location of the calcarine cortex. In nine patients, the identified patterns of activation in the visual cortex were consistent with the visual field deficits (seven homonymous hemianopsias, one homonymous central scotoma, and one inferior quadrantanopsia) and with the traditional teaching of retinotopical representation. Discordance between fMR imaging and perimetric findings was observed in one case. CONCLUSIONS: These results demonstrate that fMR imaging can be performed routinely and successfully in patients with visual abnormalities as part of a conventional neuroradiological evaluation. The technique provides essential information about the function-structure relationship specific to an individual patient and holds promise not only for diagnosis and therapy planning, but also for understanding the topography and functional specialization of the human visual cortex.     

Meningioangiomatosis in a dog: magnetic resonance imaging and neuropathological studies

A case of a dog with a long-standing history of seizures is reported. Neurological examination suggested an intracranial focal lesion, while magnetic resonance imaging disclosed a right cerebral mass with ventricular involvement. Pathological analysis of the resected specimen revealed characteristics of meningioangiomatosis.     

Cavum septum pellucidum in schizophrenia: a magnetic resonance imaging study

A research concerning the contents of Zn, Cu, Cd was carried out in 33 samples of human milk. The woman were inhabitants of Poznań (urban industrial area). The following concentrations of the metals were found: Zn 8.20 +/- 2.76 mg/l (colostrum 9.67, transitional 7.48 mg/l), Cu 0.54 +/- 0.16 mg/l (colostrum 0.47, transitional 0.60 mg/l), Cd 0.62 +/- 0.28 micrograms/l. The obtained results were considered regarding the woman's age, the day of puerperium on which the samples was taken, the number of deliveries and smoking factor. A negative correlation between the concentration of Zn and the day of puerperium was stated (p < 0.05). The contents of Zn and Cu doesn't exceed the accepted quantities in dairy products for babies. The contents of Cd in milk was the source of 1/6 PTWI given by FAO/WHO for adults. However it can present the danger to their health. The results of research point out the necessity for undertaking preventive measures and continuing the research on a larger scale.     

Functional and metabolic evaluation of the athlete's heart by magnetic resonance imaging and dobutamine stress magnetic resonance spectroscopy

BACKGROUND: The question of whether training-induced left ventricular hypertrophy in athletes is a physiological rather than a pathophysiological phenomenon remains unresolved. The purpose of the present study was to detect any abnormalities in cardiac function in hypertrophic hearts of elite cyclists and to examine the response of myocardial high-energy phosphate metabolism to high workloads induced by atropine-dobutamine stress. METHODS AND RESULTS: We studied 21 elite cyclists and 12 healthy control subjects. Left ventricular mass, volume, and function were determined by cine MRI. Myocardial high-energy phosphates were examined by 31P magnetic resonance spectroscopy. There were no significant differences between cyclists and control subjects for left ventricular ejection fraction (59+/-5% versus 61+/-4%), left ventricular cardiac index (3.4+/-0.4 versus 3.4+/-0.4 L x min(-1) x m[-2]), peak early filling rate (562+/-93 versus 535+/-81 mL/s), peak atrial filling rate (315+/-93 versus 333+/-65 mL/s), ratio of early and atrial filling volumes (3.0+/-1.0 versus 2.6+/-0.6), mean acceleration gradient of early filling (5.2+/-1.4 versus 5.8+/-1.9 L/s2), mean deceleration gradient of early filling(-3.1 +/- 0.9 versus -3.2 +/- 0.7 L/s2), mean acceleration gradient of atrial filling (3.6+/-1.8 versus 4.5+/-1.7 L/s2), and atrial filling fraction (0.23+/-0.06 versus 0.26+/-0.04, respectively). Cyclists and control subjects showed similar decreases in the ratio of myocardial phosphocreatine to ATP measured with 31P magnetic resonance spectroscopy during atropine-dobutamine stress (1.41+/-0.20 versus 1.41+/-0.18 at rest to 1.21+/-0.20 versus 1.16+/-0.13 during stress, both P=NS). CONCLUSIONS: Left ventricular hypertrophy in cyclists is not associated with significant abnormalities of cardiac function or metabolism as assessed by MRI and spectroscopy. These observations suggest that training-induced left ventricular hypertrophy in cyclists is predominantly a physiological phenomenon.     

Imaging evaluation of subluxation in Legg-Calvé-Perthes disease: magnetic resonance imaging compared with the plain radiograph

Angiotension-II (A-II) receptor maximal binding capacity (Bmax) and dissociation constants (Kd) of different blood vessels in rats with prehepatic portal hypertension were studied by radioligand binding analysis. The results showed that the A-II receptor Bmax in the thoracic aorta, superior mesenteric artery and portal vein of portal hypertensive animals (113.7 +/- 19.4 fmol/mg protein, 206.9 +/- 39.3 fmol/mg protein and 31.5 +/- 9.2 fmol/mg protein respectively) was all significantly lower than that of controls (146.8 +/- 24.5 fmol/mg protein, 297.2 +/- 44.7 fmol/mg protein and 53.4 +/- 12.1 fmol/mg protein respectively, P < 0.01). The A-II receptor Kd in the superior mesenteric artery was markedly increased in portal hypertensive animals (1.03 +/- 0.11 nmol/L) compared with that in controls (0.88 +/- 0.08 nmol/L, P < 0.05). In the thoracic aorta and portal vein, the A-II receptor Kd in portal hypertensive animals was slightly higher than that in controls, but no significant difference was observed between the two groups. The results suggested that the vascular hyporesponsiveness to A-II in portal hypertension was caused partially by a reduction in number and a decrease in affinity of vascular A-II receptors, and these changes might possibly lead to the formation of hyperdynamic circulation.     

Prostate cancer: local staging with endorectal magnetic resonance imaging

BACKGROUND: Prostate cancer has received increasing attention during the past decades. Staging of tumors before treatment is imperative for planning appropriate therapy. The purpose of this study is to assess the role of endorectal magnetic resonance imaging (MRI) in local staging of prostate cancer. METHODS: Endorectal MRI was performed in 31 patients with histologically-proven prostate cancer. MRI was done three to 100 days (mean, 32.1 days) after either transrectal ultrasonography (TRUS) with biopsy or transurethral resection of the prostate (TURP). Radical prostatectomies were performed within two weeks after MRI. The diagnostic accuracy of endorectal MRI for local tumor staging, specifically for extracapsular extension (ECE) and seminal vesicle invasion (SVI), was evaluated by correlating MRI results with histopathologic findings of whole-mount specimens. RESULTS: The accuracy of endorectal MRI for the detection of tumor presence and estimation of tumor volume was 48%. Sensitivity, specificity and positive predictive value for evaluation of ECE were 88%, 69% and 80%, respectively, and for SVI, were 66%, 84% and 50%, respectively. The overall accuracy of MRI in local tumor staging (using the TMN system) was 61%. Accuracy in differentiating localized from invasive cancer was 84%. CONCLUSION: Endorectal MRI is not accurate enough to detect tumor presence or estimate tumor volume. Diagnostic accuracy for local tumor staging is unsatisfactory. However, endorectal MRI is highly accurate in differentiating localized (stage B) from invasive (stage C) cancer.     

Preliminary experimental evaluation of an inverse source imaging procedure using a decoupled coil detector array in magnetic resonance imaging

Results of treatment for 104 forearm shaft fractures in 70 patients have been presented. In all cases included in this study an open reduction of the fracture was followed by AO plate stabilization. Functional and radiological assessment was carried out according to the criteria of Anderson et al. Excellent and good functional results were achieved in 48 cases, fair in 10 and poor in 12 cases. The ulna united in 75%, the radius in 78% (delayed union included). Cross- union occurred in three patients, one case of destabilization at fracture site was observed, no infection has been noted. AO plate osteosynthesis proved to be still valuable mode of treatment for forearm shaft fracture.     

Toe dactylitis in patients with spondyloarthropathy: assessment by magnetic resonance imaging

OBJECTIVE: To investigate using magnetic resonance imaging (MRI) the part played by flexor and extensor tenosynovitis and synovitis of the metatarsophalangeal (MTP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in producing the "sausage-like" aspect of spondyloarthropathy (SpA) toe dactylitis. METHODS: Twelve sausage-like toes and corresponding contralateral toes of 7 consecutive patients meeting Amor criteria for SpA were studied by MRI. RESULTS: All dactylitic toes showed fluid collections in the flexor synovial sheaths on MRI. Due to the sheath distension the plantar bone to skin distance was significantly increased (p < 0.05) in the dactylitic toes compared to normal contralateral toes. Peritendinous soft tissues were not involved since these were significantly thicker (p < 0.05) in normal toes. Extensor synovial sheaths were involved in only 4 dactylitic toes. Of the 36 joints of the 12 dactylitic toes only 2 MTP joints showed capsule distension. Considering MRI as the "gold standard", examination showed 100% sensitivity and specificity for flexor sheath involvement but lacked sensitivity for extensor synovial sheaths and showed a low specificity for joint capsule distension. CONCLUSION: Like finger dactylitis, toe dactylitis may also be due to flexor tenosynovitis and synovitis of MTP, PIP, and DIP joints may not be a required condition for sausage-shaped appearance. Extensor tenosynovitis may be present in addition to flexor tenosynovitis. Physical examination is a sufficient method for diagnosing toe dactylitis.