Ahmet Sigirci

Evaluation of in vivo cerebral metabolism on proton magnetic resonance spectroscopy in patients with impaired glucose tolerance and type 2 diabetes mellitus

The aim of this study was to investigate possible metabolic alterations in cerebral tissues on magnetic resonance spectroscopy (MRS) in patients with impaired glucose tolerance (IGT) and with type 2 diabetes mellitus (T2-DM). Twenty-five patients with T2-DM, 13 patients with IGT, and 14 healthy volunteers were included. Single-voxel spectroscopy (TR: 2000 ms, TE: 31 ms) was performed in all subjects. Voxels were placed in the frontal cortex, thalamus, and parietal white matter. N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and myo-inositol (MI)/Cr ratios were calculated. Frontal cortical Cho/Cr ratios were increased in patients with IGT compared to control subjects. Parietal white matter Cho/Cr ratios were significantly higher in patients with IGT when compared to patients with T2-DM. In the diabetic group, frontal cortical MI/Cr ratios were increased, and parietal white matter Cho/Cr ratios were decreased when compared to the control group. Frontal cortical NAA/Cr and Cho/Cr ratios and parietal white matter Cho/Cr ratios were decreased in diabetic patients with poor glycemic control (A1C>10%). A1C levels were inversely correlated with frontal cortical NAA/Cr and Cho/Cr ratios and with parietal white matter Cho/Cr ratios. T2-DM and IGT may cause subtle cerebral metabolic changes, and these changes may be shown with MRS. Increased Cho/Cr ratios may suggest dynamic change in membrane turnover in patients with IGT. Diabetic patients with poor glycemic control may be associated with neuronal dysfunction/damage in brain in accordance with A1C levels and, in some, extend with insulin resistance.

Doppler sonography of the inferior and superior mesenteric arteries in ulcerative colitis

The purpose of this study was to evaluate the Doppler sonographic blood‐flow parameters and spectral patterns in the inferior mesenteric artery (IMA) and superior mesenteric artery (SMA) in patients with active and inactive (remission‐phase) ulcerative colitis (UC).

Delayed myelination in a rhizomelic chondrodysplasia punctata case: MR spectroscopy findings

Rhizomelic chondrodysplasia punctata is a member of genetic peroxisomal disorders. Delayed myelination, which is probably related to the inadequacy of plasmalogens biosynthesis, is an important feature of this disorder. Direct assessment of neuropathologic aspects of RCDP syndrome such as neuronal degeneration and delayed myelination is possible with MR spectroscopy. In this report, MR spectroscopy findings (decreased Cho/Cr and increased Ins-Gly/Cr ratios and increased levels of mobile lipids) of a rhizomelic chondrodysplasia punctata case supporting delayed myelination are presented. This is the second report of MR spectroscopy examination of the specific brain metabolic changes associated with rhizomelic chondrodysplasia punctata.

Subacute sclerosing panencephalitis: Relationship between clinical stage and diffusion‐weighted imaging findings

To investigate the relationship between clinical stages and apparent diffusion coefficient (ADC) changes in the brain of patients with subacute sclerosing panencephalitis (SSPE).

Renal Interlobar Artery Parameters with Duplex Doppler Sonography and Correlations with Age, Plasma Renin, and Aldosterone Levels in Healthy Children

OBJECTIVE The objectives of this study were to compare and make correlations between age and Doppler parameters of the interlobar arteries, including synchronously obtained plasma renin and aldosterone levels and to obtain new normative data regarding acceleration time in healthy children from neonates to 16 years. SUBJECTS AND METHODS One hundred sixty-nine healthy children (72 girls and 97 boys) were classified into four groups: group 1 (< 1 year; n = 34), group 2 (range, 1-6 years; n = 48), group 3 (range, 6-12 years; n = 50), and group 4 (range, 12-16 years; n = 37). Blood samples from the renin and aldosterone were collected in the morning after bed rest and fasting. The resistive index (RI), pulsatility index (PI), and the acceleration time of the renal interlobar arteries with duplex Doppler sonography, including both kidney longitudinal lengths with grayscale sonography, were evaluated. One-way analysis of variance with the least significant difference post-hoc test and Pearsons correlation test were used to compare the differences between groups and to make correlations, respectively. An independent-sample t test was used to evaluate the differences between all parameters based on sex and to compare the left and right kidney longitudinal lengths in each group. RESULTS The RI, PI, and acceleration time were statistically significant in between-group comparisons. Only in group 4 was acceleration time not statistically significant compared with groups 2 and 3. Plasma renin levels were significantly higher in group 1 compared with groups 2 (p < 0.03) and 4 (p < 0.0001); in group 2 compared with group 4 (p < 0.05); and in group 3 compared with group 4 (p < 0.01). The plasma aldosterone levels were significantly higher only in group 1 compared with groups 2 (p < 0.001), 3 (p < 0.008), and 4 (p < 0.0001). The RI correlated linearly with the PI, plasma renin levels, and aldosterone levels and correlated inversely with acceleration time. Age had a negative correlation with the RI, PI, plasma renin levels, and aldosterone levels and correlated positively with acceleration time. There were no statistically significant differences between all parameters based on sex and no significant difference found between the right and left kidney longitudinal lengths in each group. CONCLUSION The RI in children up to 54 months old is higher than in adults. Therefore, the adult mean renal RI criterion of 0.70 should be applicable to children 54 months old and older. We showed that the age dependency of the RI was directly related to that of plasma renin and aldosterone levels in healthy children in whom Doppler parameters and blood analysis were evaluated synchronously.

Proton MR spectroscopy features of normal appearing white matter in neurofibromatosis type 1

To determine whether differences exist between neurofibromatosis type 1 (NF1) patients with or without focal lesions and healthy normal volunteers in the metabolite ratios of normal appearing white matter, 27 patients with NF1 (with parenchymal lesion, MR positive, n: 17; without parenchymal lesions, MR negative, n: 10) and 20 healthy volunteers underwent MRI and short TE (31 ms) proton MR spectroscopy (MRS). In 17 patients with parenchymal lesions, 61 focal lesions were detected by MRI. MRS was performed from normal appearing frontal and posterior parietal white matter (FWM and PWM) in NF1 and from control groups. NAA/Cr, Cho/Cr and MI/Cr ratios were calculated. Significant increase in Cho/Cr and MI/Cr ratios were found in FWM and PWM in MR negative and positive groups when compared to control group. NAA/Cr ratio in MR positive group was significantly decreased in FWM compared to control group. There were no significant differences between FWM and PWM in all metabolite ratios of MR negative group. MI/Cr ratio in MR positive group was significantly elevated in PWM compared to FWM. Metabolite changes detected by MRS could indicate demyelination and gliosis in normal appearing white matter in all NF1 patients, and additionally neuroaxonal damage in the FWM of NF1 patients with focal lesions. For that reason, in the clinical evaluation and follow-up of these patients MRS features of normal appearing white matter should be considered in addition to focal lesions.

Neutropenic enterocolitis (typhlitis) associated with infectious mononucleosis

Neutropenic enterocolitis (typhlitis) is an unusual acute complication of neutropenia, most often associated with leukaemia and lymphoma and characterized by segmental caecal and ascending colonic ulceration that may progress to necrosis, perforation, and septicaemia. We present a unique case of an 8-year-old girl with recently diagnosed infectious mononucleosis having findings consistent with typhlitis on abdominal CT.

Pyridoxine-Dependent Seizures: Magnetic Resonance Spectroscopy Findings:

Pyridoxine-dependent seizures are an extremely rare genetic disorder. Early diagnosis and treatment are important for the prevention of permanent brain damage. Elevated levels of glutamate and decreased levels of γ-aminobutyric acid (GABA) in the frontal and parietal cortices are among the characteristic features of this disorder. These metabolic abnormalities eventually lead to seizures and neuronal loss. In this case report, we present magnetic resonance spectroscopy findings of a 9-year-old girl with pyridoxine-dependent seizures with mental retardation. The N-acetyl-aspartate-to-creatine ratio was found to be decreased in the frontal and parieto-occipital cortices, which could indicate neuronal loss. Magnetic resonance spectroscopy could be a useful tool in the neuroimaging evaluation for assessment of parenchymal changes despite a normal-appearing brain magnetic resonance image in patients with pyridoxine-dependent seizures. (J Child Neurol 2004;19:75—78).

Brain MR spectroscopy in children with a history of rheumatic fever with a special emphasis on neuropsychiatric complications

PURPOSE To investigate whether there are metabolite changes in basal ganglia of children with complete healing of rheumatic fever (RF), history of Syndenham chorea (SC) and obsessive compulsive-tic disorder (OCTD) developed after RF when compared with healthy controls and each other. MATERIAL AND METHODS A total of 49 children with history of RF and 31 healthy controls were included into the study. All patients and control group underwent a detailed neuropsychiatric evaluation. Children with the history of RF were classified into three groups as; group 1: with history of RF without neuropsychiatric complications (NCRF), group 2: only with history of SC (HSC), group 3: with HSC and OCTD (OCTD). After MR imaging, single voxel MR spectroscopy was performed in all subjects. Voxels (15 x 15 x 15 mm) were placed in basal ganglia. N-acetyl aspartate (NAA)/creatin (Cr), and choline (Cho)/Cr ratios were calculated. RESULTS OCTD were detected in 13 children with HSC. NAA/Cr ratio was found to be decreased in these children when compared with NCRF (n:29), HSC without OCTD (n:7) and control groups (n:31). No significant difference was found in metabolite ratios of children with HSC without OCTD when compared with NCRF and control groups. There were no significant differences in Cho/Cr ratio between patient and control groups. CONCLUSION Although MR imaging findings was normal, MR spectroscopy findings (decreased NAA/Cr ratio) in our study support the neuronal loss in basal ganglia of children with OCTD and could indicate the development of permanent damage.

Doppler waveforms and blood flow parameters of the superior and inferior mesenteric arteries in patients having Behçet disease with and without gastrointestinal symptoms: preliminary data.

Objective. To evaluate hemodynamic changes in mesenteric arteries in patients with Behçet disease with and without gastrointestinal symptoms. Methods. Doppler sonography of mesenteric arteries was performed in 25 symptomatic and 15 asymptomatic patients having Behçet disease and in 25 healthy control subjects. The peak systolic, minimal, and mean velocities, resistive and pulsatility indexes, inner diameter, cross‐sectional area, and blood flow volume of mesenteric arteries were evaluated. The results were compared between patient groups and controls. Results. The mesenteric artery flow was significantly greater in patients in the symptomatic group than in those in the asymptomatic group or in controls. In the superior mesenteric artery, mean velocity and mean blood flow volume (0.35 ± 0.18 m/s and 711 ± 404 mL/min, respectively; P < .0001) in the symptomatic group were significantly higher than in the asymptomatic group (0.16 ± 0.07 m/s and 305 ± 168 mL/min, respectively) or in controls (0.15 ± 0.07 m/s and 290 ± 123 mL/min, respectively). The mean peak systolic velocity (1.23 ± 0.47 m/s; P < .005) in the symptomatic group was significantly higher than in controls (0.93 ± 0.23 m/s). In the inferior mesenteric artery, mean velocity and mean blood flow volume (0.25 ± 0.10 m/s and 139 ± 79 mL/min) in the symptomatic group were significantly higher than in the asymptomatic group (0.16 ± 0.07 m/s; P < .006; and 78 ± 26 mL/min; P < .007) or in controls (0.17 ± 0.07 m/s; P < .003; 83 ± 48 mL/min; P < .004). Conclusions. In this study, symptomatic patients with gastrointestinal Behçet disease were associated with a significant increase in mesenteric artery flow that could be evaluated easily on spectral patterns of arteries during Doppler sonography. The Doppler sonographic findings also revealed that intestinal involvement in patients with Behçet disease without gastrointestinal symptoms is not significantly different from that of healthy controls.