A connection between neurovascular conflicts within the cerebellopontine angle and vestibular neuritis, a case controlled cohort study.

This retrospective, observer blinded case-control study aims to compare the prevalence of neurovascular conflicts (NVCs) of the vestibulocochlear nerve and the anterior inferior cerebellar artery (AICA) in patients presenting with clinical signs of acute vestibular neuritis with and without subsequent objective vestibular function loss (VFL). 58 acute cases of clinically suspected acute vestibular neuritis were investigated with same day cranial MRI at a tertiary referral centre and compared to 61 asymptomatic controls. The prevalence of NVCs in cases with objective VFL were also compared to cases without VFL. Radiologists described the NVC as "no contact" (Grade 0), "contact < 2 mm" (Grade 1), "contact > 2 mm" (Grade 2) and "vascular loop presence" (Grade 3) without knowledge of neurotological data. Neurotological data was collected without knowledge of MRI findings. Vestibular function was tested by bithermic caloric irrigation. 26 cases (45%) showed caloric VFL (Group A), whereas 32 (55%) exhibited no VFL (Group B). Group A included 13 cases with NVCs (50%), Group B included 26 NVC cases (82%) (p = 0.012) and the control group included 16 individuals (26%) (p < 0.001 for comparison of all 3 groups). Group B had a significantly higher NVC-Grading than Group A (p = 0.009). There was no statistically significant association between NVCs and either SNHL or tinnitus (p > 0.05). Our results suggest that patients presenting with clinical signs of acute vestibular neuritis who show symmetrical caloric vestibular function test results have a significantly higher NVC prevalence in the cerebellopontine angle.

Impact of high field (3.0 T) magnetic resonance imaging on diagnosis of osteochondral defects in the ankle joint.

OBJECTIVE: To evaluate high field magnetic resonance (MR) imaging for imaging of osteochondral defects. MATERIALS AND METHODS: Nine osteochondral defects were simulated in three cadaveric talus specimens using a diamond drill. All specimens were examined on a 1.0 T MR unit and a 3.0 T MR unit. A T2-weighted turbo spin-echo (TSE) sequence with a 2 mm slice thickness and a 256 x 256 matrix size was used on both scanners. The visibility of the osteochondral separation and the presence of susceptibility artifacts at the drilling bores were scored on all images. RESULTS: Compared to the 1.0 T MR unit, the protocol on the 3.0 T MR unit allowed a better delineation of the disruption of the articular cartilage and a better demarcation of the subchondral defect. Differences regarding the visualization of the subchondral defect were found to be statistically significant (P<0.05). Differences with regard to susceptibility artifacts at the drilling bores were not statistically significant (P>0.05). The average SNR was higher using 3.0 T MRI (SNR=12), compared to 1.0 T MRI (SNR=7). CONCLUSION: High field MRI enables the acquisition of images with sufficient resolution and higher SNR and has therefore the potential to improve the staging of osteochondral defects.

Ultrafast magnetic resonance imaging of the brain.

The purpose of this study was to compare the diagnostic efficacy of single shot fast spin echo sequence (SSh-FSE), and single shot GRASE-sequence (SSh-GRASE) to the conventional T(2)-weighted fast spin echo-sequence (T(2)-FSE) in the imaging of brain disorders. Thirty three patients with high signal intensity lesions on T(2)-weighted images (n = 28), or intracerebral hemorrhage (n = 5), were examined on a 1.0 T MR scanner, with 23 mT/m gradient strength. The scan time for the conventional T(2)-FSE-sequence was 2 min 57 s, the scan time for the single shot-FSE-, and single shot-GRASE-sequences was 11 sec, and 17 sec, respectively. Twenty-one patients remained still during the examination, whereas 12 could not stay still with consecutive marked motion artifacts. Images were reviewed by three radiologists. Lesion conspicuity, image quality, and artifacts were scored on a subjective scale. Signal-to-noise ratios of lesions and normal tissue and contrast-to-noise ratios (CNR) were measured by region of interest (ROI). In the patient group without motion artifacts conspicuity for lesions > or =5 mm did not show a significant difference on conventional T(2)-FSE, single shot-FSE and single shot-GRASE. Detectability of the smaller lesions was significantly inferior on single shot-FSE-, and single shot-GRASE-sequences in artifact free images. For the patient group with motion artifacts SSh-FSE and SSh-GRASE were markedly superior to the conventional T(2)-FSE. Grey-white differentiation was better on conventional T(2)-FSE. Physiologic ferritin as well as pathologic hemosiderin depositions were slightly darker and therefore better visible on SSh-GRASE than on SSh-FSE. Conventional T(2)-FSE showed significantly more artifacts. In conclusion, SSh-FSE and SSh-GRASE imaging can be used for rapid imaging of the brain in those patients who are claustrophobic or in patients with involuntary movements due to extrapyramidal disorders, as well as in children in whom anesthesia is contraindicated or sedation is not possible.

Preoperative fast MRI of brain tumors using three-dimensional segmented echo planar imaging compared to three-dimensional gradient echo technique.

The purpose of this study was to compare the diagnostic efficacy of a newly developed T(1)-weighted three-dimensional segmented echo planar imaging (3D EPI) sequence versus a conventional T(1)-weighted three dimensional spoiled gradient echo (3D GRE) sequence in the evaluation of brain tumors. Forty-four patients with cerebral tumors and infections were examined on a 1.0 T MR unit with 23 mT/m gradient strength. The total scan time for the T(1) 3D EPI sequence was 2 min 12 s, and for a conventional 3D GRE sequence it was 4 min 59 s. Both sequences were performed after administration of a contrast agent. The images were analyzed by three radiologists. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise and contrast-to-noise-ratio (C/N) were calculated. The gray-white differentiation and C/N ratio of 3D EPI were found to be inferior to conventional 3D GRE images, but the difference was not statistically significant. In the qualitative comparison, lesion detection and conspicuity of 3D EPI images and conventional 3D GRE images were similar, but a tow-fold reduction of the scanning time was obtained. With the 3D EPI technique, a 50% scan time reduction could be achieved with acceptable image quality compared to conventional 3D GRE. Thus, the 3D EPI technique could replace conventional 3D GRE in the preoperative imaging of brain.

Rotator cuff tears in asymptomatic individuals: a clinical and ultrasonographic screening study.

OBJECTIVE: To determine the prevalence and clinical impact of rotator cuff tears in asymptomatic volunteers. MATERIALS AND METHODS: Sonographic examinations of the shoulder of 212 asymptomatic individuals between 18 and 85 years old were performed by a single experienced operator. The prevalence and location of complete rotator cuff tears were evaluated. The clinical assessment was based on the Constant Score. Magnetic resonance imaging (MRI) of the shoulder was obtained in those patients where US showed rotator cuff pathology. RESULTS: Ultrasound showed a complete rupture of the supraspinatus tendon in 6% of 212 patients from 56 to 83 years of age (mean: 67 years). MRI confirmed a complete rupture of the supraspinatus tendon in 90%. All patients reported no functional deficits, although strength was significantly lower in the patient group with complete supraspinatus tendon tear (P < 0.01). CONCLUSION: There is a higher prevalence in older individuals of rotator cuff tendon tears that cause no pain or decrease in activities of daily living.

Spiral CT and radiation dose.

Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers-patients and medical doctors who are non-radiologists-that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information.

[Diagnostic imaging of acute and chronic osteochondral lesions of the talus]. / Bildgebende Diagnostik akuter und chronischer osteochondraler Läsionen am Talus.

Acute fractures involving the articular surface of the talus run parallel to the surface and are confined to the cartilage and/or the immediate subchondral cancellous bone. Subchondral microfractures ("bone bruises"), osteochondral fractures and solely chondral fractures are different manifestations of impaction injuries that affect the articular surface. This article reviews the radiologic appearance of acute osteochondral lesions of the talus and comments on the role of the noninvasive imaging modalities. Conventional radiography and MRI provide the most relevant information and are widely discussed. A MRI classification is presented emphasizing the distinction between lesions with intact and disrupted cartilage. Osteochondrosis dissecans (OCD) is a chronic osteochondral lesion. It is diagnosed in most cases by conventional radiography. MRI has become a decisive tool in staging the lesions. Intact cartilage and contrast enhancement of the lesions are findings of MRI stage I. Cartilage defects with or without incomplete separation of the fragment, fluid around an undetached fragment, cysts larger than 5 mm in diameter and a dislodged fragment are MRI findings observed in stage II and operative treatment has to be considered.

[Acute, atraumatic changes of the lower respiratory tract in the child in thoracic roentgen imaging. Recognition and appreciation of radiological changes]. / Akute, nicht traumabedingte Veränderungen des unteren Respirationstraktes des Kindes im Thoraxröntgen. Erkennen und Verstehen radiologischer Veränderungen.

The diagnosis of acute, non-traumatic diseases of the lower respiratory tract requires exact knowledge of the specific anatomy, physiology and pathology of the pediatric chest. The absolutely and relatively smaller airways, as compared with those of adults, and the undeveloped collateral ventilation result in radiological appearances that are unique in children. Viral pneumonia is predominant only in small children up to an age of 2 years. With increasing age, there is a higher incidence of bacterial pneumonia. The differentiation of viral and bacterial etiology of a pneumonia is not possible on the basis of chest radiographs. In acute pediatric imaging, possible aspiration of foreign bodies has to be considered. Since most foreign bodies cannot be detected radiographically, indirect features such as hyperinflation or mediastinal shifts have to be evaluated. Primary lung tumors are rare in children. More common are metastases with known primary tumors. Neuroblastoma or lymphomas may mimic intrapulmonary pathologies.

Equipment availability and diagnostic strategies for suspected pulmonary embolism in Austria.

The aim of this study was to investigate equipment availability and current diagnostic strategies for suspected pulmonary embolism (PE) in Austrian hospitals. A questionnaire was sent to the medical directors of all Austrian hospitals with emergency and/or surgical, orthopedic, and medical departments. The questionnaire contained questions regarding the available equipment suitable for the imaging diagnosis of PE, the first-line and second-line imaging tests for patients with suspected PE, and additional lower extremity venous imaging and laboratory tests that complement the diagnostic armamentarium. The return rate for questionnaires was 81% (127 of 157 hospitals). There were 97% of hospitals that had the equipment to perform sonography, 59% could perform pulmonary angiography, 54% spiral CT, 19% ventilation/perfusion (V/P) scintigraphy, and 4% perfusion scintigraphy alone. Spiral-CT angiography (SCTA) was the first-line imaging study for suspected PE in 56% of hospitals, followed by echocardiography and V/P scintigraphy. Lower extremity venous imaging (47%) and, interestingly, V/P scintigraphy (43%), served as second-line imaging tests. D-dimer tests were included in the diagnostic strategy in 74% of hospitals. Spiral-CT angiography is the most commonly used primary method for suspected PE in Austrian hospitals. The V/P scintigraphy is available only in a minority of hospitals to investigate patients with suspected PE. When V/P scintigraphy is available, however, it is employed in a large number of patients per annum.

Detection of focal hepatic lesions: comparison of unenhanced and SHU 555 A-enhanced MR imaging versus biphasic helical CTAP.

The purpose of this study was to compare the diagnostic sensitivity of unenhanced magnetic resonance (MR) imaging, and MR imaging with a new superparamagnetic iron oxide (SPIO)-enhanced contrast agent (SHU 555 A) with biphasic helical computed tomography during arterial portography (CTAP) in patients with focal liver lesions. Eighteen patients with a total of 91 (78 malignant, 13 benign) proven liver lesions underwent unenhanced short tau inversion recovery (STIR), T2-weighted (T2-w) TSE, and SHU 555 A-enhanced T2-w turbo spin-echo (TSE) MR imaging and biphasic helical CTAP. The standard of reference was histopathologic analysis of resected specimens in 59 lesions, intraoperative ultrasound with biopsy in 20 lesions, and CT-guided biopsy and follow-up in 12 lesions. Diagnostic performance of the imaging modalities was compared quantitatively and qualitatively by assessing lesion involvement in liver segments. There were 68 lesions detected on unenhanced T2-w TSE, which resulted in a sensitivity of 75%. With the STIR sequence, 76 lesions were detected, for a sensitivity of 84%, and with SHU 555 A-enhanced MRI, 84 lesions were detected, for a sensitivity of 92%. CTAP detected 88 lesions, for a sensitivity of 97%. The accuracy for unenhanced T2-w TSE was 98%, for STIR 99%, for enhanced-MRI 100%, and for CTAP 95%. The specificity was 100% for SHU 555 A-enhanced MRI and 95% for CTAP. SHU 555 A-enhanced MRI was superior to nonenhanced MRI (P < 0.05) and equivalent to CTAP in terms of sensitivity. Due to the absence of false-positive results on SHU 555 A-enhanced MRI, the specificity and accuracy of enhanced MRI were higher than those of CTAP, but the difference was not statistically significant (P = 0.134).