Early muscle and brain ultrastructural changes in polymerase gamma 1-related encephalomyopathy.

Mutations affecting the mitochondrial DNA-polymerase gamma 1 (POLG1) gene have been shown to cause Alpers-Huttenlocher disease. Ultrastructural data on brain and muscle tissue are rare. We report on ultrastructural changes in brain and muscle tissue of two sisters who were compound heterozygous for the c.2243G>C and c.1879C>T POLG1 mutations. Patient 1 (16 years) presented with epilepsia partialis continua that did not respond to antiepileptic treatment. Neuroimaging showed right occipital and bithalamic changes. Light microscopy from a brain biopsy performed after 3 weeks suggested chronic encephalitis showing astro- and microgliosis as well as perivascular CD8-positive T-cells. However, immunosuppressive therapy failed to improve her condition. When her 17-year-old sister (patient 2) also developed epilepsy, an intensified search for metabolic diseases led to the diagnosis. On electron microscopy mitochondrial abnormalities mainly affecting neurons were detected in the brain biopsy of patient 1, including an increase in number and size, structural changes and globoid inclusions. In patient 2, light and electron microscopy on a muscle biopsy confirmed a mitochondrial myopathy, also revealing an increase in mitochondrial size and number, as well as globoid inclusions. Neurons may be the primary target of mitochondrial dysfunction in brains of patients with Alpers disease related to POLG1 mutations. During early disease stages, brain histopathology may be misleading, showing reactive inflammatory changes.

Syringomyelia in preterm children with posthemorrhagic occlusive hydrocephalus.

OBJECTIVE AND IMPORTANCE: Whereas posthemorrhagic hydrocephalus is well known after preterm birth, its association with syringomyelia has been reported only once. Here, we describe two additional patients showing this rare constellation. CLINICAL PRESENTATION: The children had been born after 27 and 28 completed weeks of gestation, respectively. Both had developed neonatal cerebral hemorrhages. At the age of 4 years, patient 1 presented with progressive ataxia leading to the diagnosis of internal hydrocephalus and extensive syringomyelia. In patient 2, progressive ventriculomegaly and syringomyelia were diagnosed at the age of 4 weeks. INTERVENTION: In both children, ventriculoperitoneal shunting resulted in clinical improvement, decrease of the ventricular size, and regression of the syringomyelia. After surgery, patient 1 developed a subdural hematoma and patient 2 parenchymatous cerebral hemorrhages. CONCLUSION: The combination of syringomyelia and posthemorrhagic hydrocephalus may be more frequent than commonly assumed. Therefore, neurological deterioration may mandate spinal MRI in addition to cerebral MRI. Syringomyelia seems to result from impaired ventricular cerebrospinal fluid drainage as it regresses after ventriculoperitoneal shunting. Bleeding may complicate the postsurgical relaxation of distended brain parenchyma.

T2 hyperintense signal of the central tegmental tracts in children: disease or normal maturational process?

INTRODUCTION: Cerebral central tegmental tract hyperintense signal on T2-weighted MRI (CTTH) is known from various clinical conditions, including children treated with vigabatrin (VGB) for West syndrome (WS), with hypoxic-ischemic brain injury, and metabolic diseases. Considering this clinical diversity, we hypothesized that CTTH might primarily mirror a physiologic process. METHODS: We retrospectively analysed brain MRI data of the central tegmental tracts deriving from four different groups: (1) children with WS and VGB therapy (WS+VGB+), (2) children with WS but without VGB therapy (WS+VGB-), (3) children with different neurological diseases (WS-VGB-; maximum age 15 years), and (4) controls younger than 25 months of age (this age includes the peak age of WS). RESULTS: CTTH were detected in 4/17 WS+VGB+ children (24%), 4/34 WS+VGB- children (12%), 18/296 WS-VGB- children (6%), and 8/112 controls (7%). Independently from the underlying diagnosis, CTTH showed a peak age during early infancy and were not found before 4 months and after 7 years of life. The rate of CTTH among WS children ± VGB therapy was similar so that VGB therapy seems of minor etiological impact. However, comparison of WS patients younger than 25 months of age (CTTH present in 7/40) with age-matched controls (CTTH present in 8/112) revealed that CTTH tend to be more frequent among WS patients in general. CONCLUSIONS: Our study suggests that CTTH represents a physiological maturation-related process. The high prevalence of CTTH among patients with WS indicates that this physiological process may be modified by additional endo- or exogeneous factors.

Prospective evaluation of image quality with use of a patient image gallery for dose reduction in pediatric 16-MDCT.

OBJECTIVE: The purposes of this study were to evaluate prospective adjustment of dose settings in pediatric 16-MDCT by use of computer-simulated images in a patient image gallery and to compare the dose reduction achieved with that of standard pediatric protocols. SUBJECTS AND METHODS: The image gallery consisted of images from weight-dependent sample examinations performed with varied simulated tube current-exposure time settings. The scanning parameters prospectively chosen on the basis of the image quality of the image gallery were used for 30 16-MDCT examinations (chest, n = 15; abdomen, n = 8; pelvis, n = 7) of 22 children (14 boys, eight girls; mean age, 6.8 +/- 5.8 years; mean body weight, 26.7 +/- 19.6 kg). Three blinded radiologists used a 4-point grading scale to rate the overall image quality of the image gallery and the 16-MDCT scans. Objective and subjective image quality was assessed for the simulated and actual CT scans. The concordance correlation coefficient (K) was determined. RESULTS: There was mainly moderate concordance with regard to objective (chest, K = 0.69; abdomen, K = 0.33; pelvis, K = 0.55) and subjective (chest soft-tissue window, kappa coefficient [kappa] = 0.00; chest lung window, kappa = 0.53; abdomen, kappa = 1.00; pelvis, kappa = 0.48) analysis of image gallery compared with actual 16-MDCT examinations. Compared with use of previous weight-adapted pediatric standard protocols, use of an image gallery resulted in further dose reduction for abdominal and pelvic CT but not for thoracic CT. CONCLUSION: A patient image gallery can be used as a basis for pediatric 16-MDCT examinations. The gallery provides a preexamination overview of expected image quality. Radiation exposure can be optimized with regard to patient weight and the image quality needed to answer the clinical question.

Dose reduction during CT fluoroscopy: phantom study of angular beam modulation.

PURPOSE: To prospectively evaluate, in a phantom, the dose reductions achievable by using angular beam modulation (ABM) during computed tomographic (CT) fluoroscopy-guided thoracic interventions. MATERIALS AND METHODS: To enable measurement of organ doses and effective patient dose, a female Alderson-Rando phantom was equipped with thermoluminescent dosimeters (TLDs) in 41 positions, with three TLDs in each position. Additionally, the local dose was assessed in 22 locations above the phantom to estimate the radiation exposure to the radiologist's hand and the patient's skin dose during thoracic interventions. Radiation exposure was performed with a 64-section multidetector CT scanner in the CT fluoroscopy mode, simulating a CT fluoroscopy-guided chest intervention. Effective dose, breast dose, and the dose to the radiologist's hand during the simulated chest intervention were measured with and without ABM. Image noise as an indicator for image quality was compared for both settings. Statistical significance of the measured dose reductions and the image noise was tested by using the paired-samples t test, with P < .05 indicating a significant difference. RESULTS: ABM significantly reduced the effective patient dose by 35%, the skin dose by 75%, the breast dose by 47% (P < .001 for all), and the physician's hand dose by between 27% (scattered radiation, P = .007) and 72% (direct radiation, P < .001). No significant difference was found in a comparison of the image noise with and that without ABM. CONCLUSION: ABM leads to significant dose reductions for both patients and personnel during CT fluoroscopy-guided thoracic interventions, without impairing image quality.

Imaging of congenital anomalies and acquired lesions of the inner ear.

Imaging of the temporal bone is under continous developement. In the recent decades the technical advances of magnetic resonance imaging and computed tomography have contributed to improved imaging quality in assessment of the temporal bone. Dedicated imaging protocols have been developed and are routinely employed in most institutions. However, imaging interpretation remains challenging, since the temporal bone is an anatomically highly complex region and most diseases of the inner ear occur with low incidence, so that even radiologists experienced in the field may be confronted with such entities for the first time. The current review gives an overview about symptoms and imaging appearance of malformations and acquired lesion of the inner ear.

Low to medium WU-virus titers in young children with lower respiratory tract infections.

The WU-virus (WUV), a novel polyomavirus, has recently been recovered from respiratory tract samples. Within a study collective of children with severe lower respiratory tract disease, 3% of the patients tested WUV positive. Viral loads ranged from 5 x 10(2) copies/ml to 1 x 10(4) copies/ml. The WUV genome-positive patients did not display specific clinical or radiological characteristics to be distinguished from other respiratory tract infections.

The accuracy of 1- and 3-mm slices in coronary calcium scoring using multi-slice CT in vitro and in vivo.

The accuracy of coronary calcium scoring using 16-row MSCT comparing 1- and 3-mm slices was assessed. A thorax phantom with calcium cylinder inserts was scanned applying a non-enhanced retrospectively ECG-gated examination protocol: collimation 12 x 0.75 mm; 120 kV; 133 mAs(eff). Thirty-eight patients were examined using the same scan protocol. Image reconstruction was performed with an effective slice thickness of 3 and 1 mm. The volume score, calcium mass and Agatston score were determined. Image noise was measured in both studies. The volume score and calcium mass varied less than the Agatston score. The overall measured calcium mass compared to the actual calcium mass revealed a relative difference of +2.0% for 1-mm slices and -1.2% for 3-mm slices. Due to increased image noise in thinner slices in the patient study (26.1 HU), overall calcium scoring with a scoring threshold of 130 HU was not feasible. Interlesion comparison showed significantly higher scoring results for thinner slices (all P<0.001). A similar accuracy comparing calcium scoring results of 1- and 3-mm slices was shown in the phantom study; therefore, the potentially necessary increase of the patient's dose in order to achieve assessable 1-mm slices with an acceptable image-to-noise-ratio appears not to be justified.

Value of virtual tracheobronchoscopy and bronchography from 16-slice multidetector-row spiral computed tomography for assessment of suspected tracheobronchial stenosis in children.

PURPOSE: To evaluate the value of dose-reduced 16-slice multidetector-row spiral computed tomography (16-MDCT) using virtual tracheobronchoscopy (VTB) and virtual bronchography (VBG) in children with suspected tracheobronchial stenosis. MATERIALS AND METHODS: 12 children (4 d to 3 years, body weight 1.2 kg to 13.5 kg) with stridor and suspected tracheobronchial stenosis were examined by contrast-enhanced low-dose 16-MDCT. Conventional axial slices, MPRs, VTB, and VBG were calculated. Image findings were correlated with the results of fiberoptic bronchoscopy (12 out of 12) as a gold standard and subsequent surgery (8 out of 12). RESULTS: VTB and VBG demonstrated the fiberoptic bronchoscopically suspected tracheal stenosis in 11 of 12 children due to vascular compression because of the brachiocephalic trunk (6), a double aortic arch (2), a vascular compression of the left main bronchus (2), and a right aberrant subclavian artery (1). Eleven out of 12 stenoses were correctly depicted by conventional axial slices, MPRs, VTB, and VBG. Dose reduction was 79 to 85.8% compared to a standard adult chest CT. CONCLUSION: Dose-reduced 16-MDCT with the use of VTB and VBG is effective for the evaluation of tracheobronchial stenosis in children and correlates well with fiberoptic bronchoscopy.

Sharp central venous recanalization by means of a TIPS needle.

The purpose of this study was to perform an alternative technique for recanalization of a chronic occlusion of the left brachiocephalic vein that could not be traversed with a guidewire. Restoration of a completely thrombosed left brachiocephalic vein was attempted in a 76-year-old male hemodialysis patient with massive upper inflow obstruction, massive edema of the face, neck, shoulder, and arm, and occlusion of the stented right brachiocephalic vein/superior vena cava. Vessel negotiation with several guidewires and multipurpose catheters proved unsuccessful. The procedure was also non-viable using a long, 21 G puncture needle. Puncture of the superior vena cava (SVC) at the distal circumference of the stent in the right brachiocephalic vein/superior vena cava, however, was feasible with a transjugular intrahepatic portosystemic shunt (TIPS) set under biplanar fluoroscopy using the distal end of the right brachiocephalic vein as a target, followed by balloon dilatation and partial extraction of thrombotic material of the left brachiocephalic vein with a wire basket. Finally, two overlapping stents were deployed to avoid early re-occlusion. Venography demonstrated complete vessel patency with free contrast media flow via the stents into the SVC, which was reconfirmed in follow-up examinations. Immediate clinical improvement was observed. Venous vascular recanalization of chronic venous occlusion by means of a TIPS needle is feasible as a last resort under certain precautions.

Phase-inversion tissue harmonic imaging compared with conventional B-mode ultrasound in the evaluation of pancreatic lesions.

The aim of this study was to compare the diagnostic sensitivity, specificity, and image quality of conventional B-mode US (BM) and phase-inversion tissue harmonic imaging (PTHI) regarding pancreatic pathology. In a prospective study, 107 patients, aged between 28 and 85 years, underwent US examinations of the pancreas with both BM and PTHI in a randomly chosen order. As diagnostic reference, either contrast-enhanced CT or MRI examinations of the upper abdomen were obtained in all patients. Sensitivity and specificity were evaluated using the Student's t test. Differences in overall image quality, lesion conspicuity, fluid-solid differentiation, and delineation of the pancreatic tail were analyzed using Wilcoxon's signed ranks test and Bowker's symmetry test. Sixteen of 107 examined patients (15%) were non-diagnostic and excluded due to technical limitations such as abdominal gas. A total of 60 pancreatic lesions (cysts, acute pancreatitis, dilatation of the pancreatic duct, calcifications, and solid tumors) were diagnosed by CT or MRI. Phase-inversion tissue harmonic imaging had a higher sensitivity of 70% (14 of 20) than BM (60%; 24 of 40) for the detection of pancreatic lesions; however, the difference was not statistically significant ( p=0.46). In the assessment of lesions <1 cm of size, PTHI had a sensitivity of 70% and BM 46.7%, whereby the difference again was not statistically significant. Phase-inversion tissue harmonic imaging proved to be superior to BM regarding overall image quality ( p<0.0001), lesion conspicuity ( p=0.0045), and fluid-solid differentiation ( p=0.0002), as well as the delineation of the pancreatic tail ( p<0.0001). These differences were statistically significant. The statistically significant improvement of image quality with regards to lesion conspicuity, fluid-solid differentiation, and delineation of the pancreatic tail favors the use of PTHI when evaluating the pancreas with US. Sensitivity for pancreatic lesions is increased with PTHI in comparison with conventional sonography (BM), especially in lesions <1 cm in diameter, although the difference was not statistically significant.

Diagnostic accuracy of phase-inversion tissue harmonic imaging versus fundamental B-mode sonography in the evaluation of focal lesions of the kidney.

OBJECTIVE: We compared phase-inversion tissue harmonic imaging with fundamental B-mode sonography in the evaluation of focal lesions of the kidney. SUBJECTS AND METHODS: For our prospective study, 114 patients underwent sonography of the kidneys in both modes, fundamental B-mode sonography and phase-inversion tissue harmonic imaging, in a randomly chosen scanning order. Imaging parameters were standardized. Sonographic diagnoses were made under real-time conditions by the examining radiologist. All sonographic diagnoses were compared with a diagnostic reference modality: contrast-enhanced CT, contrast-enhanced MR imaging, or histopathology. Three radiologists different from the examiners evaluated overall image quality, lesion conspicuity, and fluid-solid differentiation for both modalities using hard-copy images. RESULTS: In 70 patients, fundamental B-mode sonography as the first technique depicted 73 of 111 lesions 10 mm or larger and enabled 71 lesions to be correctly characterized (sensitivity, 65.8%; accuracy, 64.0%). As the first mode, phase-inversion tissue harmonic imaging depicted 57 of 65 focal lesions and enabled 54 lesions to be accurately classified in 44 patients (sensitivity, 87.7%; accuracy, 83.1%). The differences in sensitivity and accuracy were statistically significant (95% confidence interval). For overall image quality, lesion conspicuity, and fluid-solid differentiation phase-inversion harmonic imaging was superior to fundamental B-mode sonography (p < 0.0001). CONCLUSION: Phase-inversion tissue harmonic imaging is superior to fundamental B-mode sonography in the sonography of focal kidney lesions because phase-inversion tissue harmonic imaging has better overall image quality, lesion conspicuity, and fluid-solid differentiation. In six cases, phase-inversion tissue harmonic imaging added crucial diagnostic information that changed patient management.