[Dynamic contrast-enhanced magnetic resonance imaging findings of mass lesions of the pontocerebellar angle]. / Pontoserebellar köse tümörlerinde dinamik kontrastli manyetik rezonans görüntüleme bulgulari.

OBJECTIVES: The differential diagnosis of mass lesions of the pontocerebellar angle is not always possible by conventional magnetic resonance imaging (MRI). In this study, we investigated the role of dynamic contrast-enhanced MRI in the differential diagnosis of acoustic neurinoma, meningioma, and paraganglioma. PATIENTS AND METHODS: Twelve patients (8 females, 4 males; mean age 47.5 years; range 8 to 71 years) whose diagnoses were acoustic neurinoma (n=3), paraganglioma (n=5), and meningioma (n=4) were evaluated by simultaneous conventional and dynamic contrast-enhanced MRI. Prior to postcontrast T1-weighted images, dynamic MRI was obtained. On these images, maximum contrast enhancement (Cmax) and time to peak enhancement (Tmax) were calculated at 15 different time points. Time-signal intensity curve patterns of the lesions were compared. RESULTS: According to the four main time-signal intensity curve patterns described in the literature, acoustic neurinomas, meningiomas, and paragangliomas exhibited type C, type A-B, and type A curve patterns, respectively. CONCLUSION: Our results suggest that dynamic contrast MRI may have an additional but limited role in the differential diagnosis of extra-axial intracranial tumors such as those of the pontocerebellar angle.

Effect of nasal septal deviation on total ethmoid cell volume.

BACKGROUND: The aim of this study was to evaluate the effect of nasal septal deviation (NSD) on ethmoid cell volume and to determine whether there was any correlation between NSD grade and ethmoid cell volume. METHODS: Forty computerized tomography (CT) scans from patients with rhinosinusitis symptoms with NSD were evaluated. Septal deviations were classified into three groups according to the degree of deviation on CT. Ethmoid cell volumes were measured and the relationship between NSD and ethmoid cell volume was investigated. RESULTS: There was a moderate but significant negative correlation between the septal deviation angle and the percentage of the ethmoid cell volumes (p = 0.001, r = -0.5152, r2 = 0.2654). Total ethmoid cell volume on the ipsilateral side compared with the contralateral side was found to decrease as the degree of NSD increased. CONCLUSIONS: Nasal septal deviation affects the total ethmoid cell volume of the nasal cavity. The results of our study underline the role of ethmoid cell volume in the compensation mechanism equalizing the nasal cavity airflow changes due to NSD.

Giant axonal neuropathy: MRS findings.

Giant axonal neuropathy (GAN) is a rare genetic disease of childhood involving the central and peripheral nervous systems. Axonal loss with several giant axons filled with neurofilaments is the main histopathological feature of peripheral nerve biopsies in this disease. Routine neuroimaging studies reveal diffuse hyperintensities in cerebral and cerebellar white matter. In this case report, the authors present the brain magnetic resonance spectroscopic features (normal N-acetylaspartate/creatine and increased choline/creatine and myoinositol/creatine ratios), which might indicate the absence of neuroaxonal loss and the presence of significant demyelination and glial proliferation in white matter, of an 11-year-old boy diagnosed with GAN.

An unusual case of acute disseminated encephalomyelitis confined to brainstem.

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder usually encountered in children or adolescents and characterized by multifocal neurological deficits of rapid onset. Typical target areas of demyelination include the corona radiata, centrum semiovale, periventricular white matter, cerebellar peduncles and brainstem. Involvement of deep gray matter nuclei is also frequent. We report a 6-year-old boy with ADEM who had only brainstem involvement. Serial magnetic resonance images representing the stage of disease and response to steroid treatment are presented.

Occupational prolonged organic solvent exposure in shoemakers: brain MR spectroscopy findings.

Our purpose was to investigate, by magnetic resonance (MR) spectroscopy, the metabolite changes in the brains of subjects in the shoemaking industry who had been chronically exposed to organic solvents. A total of 49 male subjects and 30 age-matched healthy volunteers underwent detailed neurological and psychiatric examinations. All subjects had long-echo [repetition time (TR) 2000 ms, echo time (TE) 136 ms] single-voxel MR spectroscopy. Voxels (15 x 15 x 15 mm(3)) were placed in the parietal white matter, thalamus, and basal ganglia. N-acetylaspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios were calculated. There was no significant difference between the study subjects and the control group in NAA/Cr ratios obtained from thalamus, basal ganglia, and parietal white matter. Cho/Cr ratios in thalamus, basal ganglia, and parietal white matter were found to be significantly increased compared to controls. There was a positive correlation between basal ganglia Cho/Cr ratio and duration of exposure (r = 0.63). MR spectroscopy should be performed to reveal metabolite changes and determine the degree of brain involvement in solvent-related industry workers.

The cisternal segment of the abducens nerve in man: three-dimensional MR imaging.

PURPOSE: The goal of this study was to identify the abducens nerve in its cisternal segment by using three-dimensional turbo spin echo T2-weighted image (3DT2-TSE). The abducens nerve may arise from the medullopontine sulcus by one singular or two separated rootlets. MATERIAL AND METHODS: We studied 285 patients (150 males, 135 females, age range: 9-72 years, mean age: 33.3 +/- 14.4) referred to MR imaging of the inner ear, internal auditory canal and brainstem. All 3D T2-TSE studies were performed with a 1.5 T MR system. Imaging parameters used for 3DT2-TSE sequence were TR:4000, TE:150, and 0.70 mm slice thickness. A field of view of 160 mm and 256 x 256 matrix were used. The double rootlets of the abducens nerve and contralateral abducens nerves and their relationships with anatomical structures were searched in the subarachnoid space. RESULTS: We identified 540 of 570 abducens nerves (94.7%) in its complete cisternal course with certainty. Seventy-two cases (25.2%) in the present study had double rootlets of the abducens nerve. In 59 of these cases (34 on the right side and 25 on the left) presented with unilateral double rootlets of the abducens. Thirteen cases presented with bilateral double rootlets of the abducens (4.5%). CONCLUSION: An abducens nerve arising by two separate rootlets is not a rare variation. The detection of this anatomical variation by preoperative MR imaging is important to avoid partial damage of the nerve during surgical procedures. The 3DT2-TSE as a noninvasive technique makes it possible to obtain extremely high-quality images of microstructures as cranial nerves and surrounding vessels in the cerebellopontine cistern. Therefore, preoperative MR imaging should be performed to detect anatomical variations of abducens nerve and to reduce the chance of operative injuries.

[Are there effects due to the existence of coronary collateral circulation on left ventricular function in patients with coronary artery disease?]. / Koroner arter hastaliginda kollateral dolasim varliginin sol ventrikül fonksiyonlari uzerine etkisi olabilir mi?

OBJECTIVE: The role of coronary collateral circulation (CCC) on the improvement of left ventricular function in coronary artery disease is controversial. The aim of this study is to investigate the effect of CCC on left ventricular function in patients with ischaemic heart disease. METHODS: Accordingly, 76 patients (39 female, 37 male, mean age--61 +/- 17 years) who had single vessel disease with > 85% narrowing in left anterior descending coronary artery were enrolled in this study. Coronary collateral circulation was determined according to the Rentrop classification (Class 0 = no collateral circulation; class 1 = small branches of occluded vessel fill with CCC; class 2 = epicardial segment of the occluded vessel partially fills with CCC; class 3 = epicardial segment of the occluded vessel totally fills with CCC). Left ventricular function was assessed with echocardiography and left ventricular regional wall motion score (0 = normokinetic; 1 = hypokinetic; 2 = akinetic; 3 = dyskinetic; 4 = aneurysmatic). Rentrop classification of the patients were compared with left ventricular regional wall motion scores and ejection fractions. RESULTS: Twenty one of 76 patients had no collateral circulation. The regional wall motion score of class 0 patients was similar with that of patients with CCC (class 1,2,3) (2.28 +/- 2.1 vs 3.39 +/- 2.1, p > 0.05). Particularly, the regional wall motion score was positively correlated with Rentrop classes (p < 0.05). Class 3 patients had the highest wall motion score (4.24 +/- 2.5, p < 0.05). Patients with and without CCC had similar left ventricular ejection fractions (49 +/- 11 vs 46 +/- 17, p > 0.05). CONCLUSION: This study showed that development of CCC has no preventive effect on left ventricular functions in patients with coronary artery disease. Interestingly as the stage of CCC increases left ventricular function worsens. It may be the result of the fact that patients with well developed CCC have more severe coronary artery disease.

The role of MRS in the differentiation of benign and malignant soft tissue and bone tumors.

OBJECTIVE: The aim of our study was to investigate the value of choline in the discrimination of benign and malignant soft tissue and bone tumors. MATERIALS AND METHODS: The study group consisted of thirty subjects with bone or soft tissue tumors larger than 1.5 cm in diameter. The experiments were performed in a 1.5T MR scanner. Coils were selected according to specific locations. A single-voxel MRS was performed for three different TE (time to echo) (31, 136, 272 ms). The volume of interest was positioned on the brightest enhancement. The presence of a cholin peak on at least 2 of these spectrums was considered as the marker of malignancy. The sensitivity, specificity and accuracy of the MRS in the detection and diagnosis of malignant lesions were calculated. The reproducibility of MRS and histopathological results were tested with kappa statistics. RESULTS: Histopathologically, 18 (60%) of the lesions were classed as malignant whereas 12 (40%) were classed as benign. With MRS, 15 (50%) of these lesions were classed as malignant and 15 (50%) as benign. Two patients who were found spectroscopically to have malignant tumors were shown histopathologically to have benign types. Five patients with an MRS showing a benign type were classed with malignant types in histopathological examinations. MRS had a sensitivity rate of 72.2%, specificity of 83.3%, and an accuracy rate of 76.6% in detecting malignant bone and soft tissue tumors. The interrater reliability of both techniques had a kappa value of 0.533. CONCLUSIONS: MRS may help in the differentiation of benign and malignant soft tissue and bone tumors.

Long-term effects of percutaneous nephrolithotomy on renal morphology and arterial vascular resistance as evaluated by color Doppler ultrasonography: preliminary report.

We evaluated the long-term effects of percutaneous nephrolithotomy (PNL) on renal morphology and vascular resistance. Parenchyma thickness, echogenicity and resistive index (RI) of upper, middle and lower poles of operated and contralateral kidneys of 41 patients with 82 renal units who underwent unilateral PNL with single pole access between 2000 and 2002 were examined separately by color Doppler ultrasonography. Mean patient age and duration between PNL and evaluation time were 38.29+/-11.53 years and 46.44+/-10.9 months, respectively. In operated kidney, mean RI, parenchyma thickness and echogenicity of the access pole were not statistically different than those of the adjacent two poles (0.608+/-0.053 vs. 0.608+/-0.052 for RI, P=0.895; 11.46+/-2.58 vs. 11.41+/-2.68 mm for parenchyma thickness, P=0.838; 0.049+/-0.31 vs. 0.073+/-0.33 for parenchyma echogenicity, P=0.160, respectively). Although mean RI and parenchyma thickness of access pole were statistically significantly different than the mean values of contralateral kidney (0.562+/-0.032 and 14.31+/-1.37 mm, respectively), no statistical difference was found between mean parenchyma echogenicities of both of them (echogenicity of contralateral kidney was 0, P=0.317). No significant difference was found between the average echogenicities of the three poles of the operated and contralateral kidneys (0.063+/-0.32 vs. 0, P=0.080). In 14 patients RI decreased from 0.694+/-0.058 to 0.602+/-0.056 in operated kidney (P=0.001) and from 0.604+/-0.06 to 0.559+/-0.031 in contralateral kidney (P=0.018) following PNL. It seems that PNL does not cause renal scarring, renal parenchymal loss or increase in renal vascular resistance in the long term. However, prospective studies must be performed for more definitive conclusions.

[MR spectroscopy in the differential diagnosis of focal brain lesions in neurofibromatosis type 1 patients]. / Tip 1 nörofibromatozisli hastalarda fokal beyin lezyonlarinin ayirici tanisinda MR spektroskopi.

PURPOSE: To determine the role of MR spectroscopy in the differential diagnosis of focal brain lesions in neurofibromatosis type 1. MATERIALS AND METHODS: Fifteen patients with neurofibromatosis type 1 were evaluated by routine MRI and single voxel MR spectroscopy (TE: 31). The posterior parietal white matter of 20 age-matched healthy volunteers constituted the control group. NAA/Cr, Cho/Cr and MI/Cr ratios were calculated and compared with the control group. RESULTS: A total of 58 focal brain lesions were detected by MR imaging. When patients with hamartomas and gliomas were compared with the control group, a decrease in the NAA/Cr ratio, and a significant increase in Cho/Cr and MI/Cr ratios were found. The decrease in the NAA/Cr ratio and the increase in Cho/Cr and MI/Cr ratios of gliomas were significant when compared with hamartomas. With MRI and MR spectroscopy findings, 52 hamartomas and 6 gliomas were detected. CONCLUSION: Since MR spectroscopy has the ability to detect cellular metabolic changes, it could provide additional information to MR imaging about the differential diagnosis and treatment planning of focal parenchymal lesions in neurofibromatosis type 1.

Temporary and permanent inferior vena cava filter combination in a young patient: to implant or not to implant?

The decision to implant vena cava filters, either temporary or permanent, is difficult in young patients. We present the case of a young man with pulmonary embolism in whom temporary and permanent inferior vena cava filters were implanted. The decision process is discussed in relation to the current literature.

Increased p-wave duration and p-wave dispersion in patients with aortic stenosis.

BACKGROUND: P-wave dispersion (PWD), defined as the difference between the maximum and minimum P-wave duration, has been proposed as being useful for the prediction of paroxysmal atrial fibrillation (AF). AF is the most common arrhythmia and an important prognostic indicator for clinical deterioration in patients with aortic stenosis (AS). The aim of the present study was to evaluate PWD in patients with AS. METHODS: The study population consisted of two groups: Group I consisted of 98 patients with AS (76 men, 22 women; aged 63 +/- 8 years) and group II consisted of 98 healthy subjects (same age and sex) without any cardiovascular disease. A 12-lead electrocardiogram was recorded for each subject. The P-wave duration was calculated in all leads of the surface electrocardiogram. The difference between the maximum and minimum P-wave duration was calculated and was defined as the PWD. All patients and control subjects were also evaluated by echocardiography to measure the left atrial diameter, left ventricular ejection fraction, left ventricular wall thicknesses, and the maximum and mean aortic gradients. Patients were also evaluated for the presence of paroxysmal AF. RESULTS: Maximum P-wave duration and PWD of group I were found to be significantly higher than those of group II. In addition, patients with paroxysmal AF had significantly higher PWD than those without paroxysmal AF. There was no significant difference between the two groups regarding minimum P-wave duration. In addition, there was no significant correlation between echocardiographic variables and PWD. CONCLUSION: PWD, indicating increased risk for paroxysmal AF, was found to be significantly higher in patients with AS than in those without it. Further assessment of the clinical utility of PWD for the prediction of paroxysmal AF in patients with severe AS will require longer prospective studies.

[Associated brain anomalies and clinical findings in corpus callosum dysgenesis]. / Korpus kallozum disgenezisine eslik eden beyin anomalileri ve klinik bulgular.

PURPOSE: The aim of this study was to evaluate the relationship between the types of the corpus callosum dysgenesis, the associated brain anomalies and clinical findings. MATERIALS AND METHODS: We analyzed the MR imaging findings in 169 patients with callosal dysgenesis. Corpus callosum dysgenesis was categorized into agenesis, hypogenesis and hypoplasia. The associated brain anomalies and clinical findings were evaluated. RESULTS: Associated brain anomalies were observed in 148 patients (87.5%). Twenty-one patients (12.4%) had isolated corpus callosum dysgenesis. Dysgenesis included agenesis in 22 (%13), hypogenesis in 46 (27.2%), and hypoplasia in 101 (59.7%) patients. The clinical findings were most commonly observed in patients with hypoplasia. CONCLUSION: The presence of corpus callosum dysgenesis is a strong indication of possible associated brain anomalies. Corpus callosum dysgenesis and associated brain anomalies should be investigated in children with developmental delay, seizures and microcephaly.