Biomedical subjects

W Heindel

Publications and source records attributed to W Heindel.

At least 19 recordsLinked to original sources

PubMed2007

[Molecular and parametric imaging with iron oxides].

Superparamagnetic iron oxide (SPIO) contrast agents, clinically established for high resolution magnetic resonance imaging of reticuloendothelial system containing anatomical structures, can additionally be exploited for the non-invasive characterization and quantification of pathology down to the molecular level. In this context, SPIOs can be applied for non-invasive cell tracking, quantification of tissue perfusion and target specific imaging, as well as for the detection of gene expression. This article provides an overview of new applications for clinically approved iron oxides as well of new, modified SPIO contrast agents for parametric and molecular imaging.

Cell Separation↗

PubMed2006

[Whole-heart coronary MR angiography -- initial results].

PURPOSE: To evaluate a new coronary MR angiography technique covering the whole coronary artery tree in one data set acquisition. MATERIALS AND METHODS: Six healthy volunteers and 15 patients with known CAD were examined with a navigator gated and corrected (NAV) free-breathing 3D steady-state free precession sequence covering the whole heart (WH-MRA) (TR = 5.4, TE = 2.7, SENSE factor = 2, 160 slices, 0.75 mm reconstructed slice thickness, in-plane resolution = 0.99 x 0.99 mm(2), scan time 14 min [50 % NAV efficiency]) and a vessel targeted 3D SSFP MRA sequence (t-MRA) (TR = 5.6 ms, TE = 2.8 ms, 20 slices of 1.5 mm reconstructed slice thickness, in-plane resolution = 0.99 x 0.99 mm(2), scan time = 7 min [50 % NAV efficiency]). Subjective image quality (4-point scale) and objective image quality parameters including vessel sharpness, vessel diameter and CNR were calculated for WH-MRA and t-MRA. In patients, the accuracy for detection of stenosis larger than 50 % was compared to the accuracy of X-ray coronary angiography (XA), which was considered the standard. RESULTS: WH-MRA demonstrated good vessel visibility in healthy subjects (100 %) whereas vessel visibility in patients was limited (78 % in an 8 segment evaluation). Vessel sharpness was inferior to that of t-MRA in patients (37 vs. 42 %) but equal in healthy subjects (42 %). Vessel diameter did not differ significantly between WH-MRA and t-MRA. CNR was significantly reduced for WH-MRA (CNR 7.4 vs. 11.5). The diagnostic accuracy for the detection of CAD was comparable for both MRA approaches (85.5 vs. 86.2 %). CONCLUSION: WH-MRA allows good coronary artery visualization in healthy subjects and patients and provides a simplified scanning procedure and advantages in 3D post-processing. Regarding image parameters and the detection of CAD, the results are comparable to those acquired with t-MRA. The major disadvantage remains the high number of diagnostically insufficient images.

Adult↗

PubMed2006

Tumor staging using whole-body high-resolution 16-channel PET-CT: does additional low-dose chest CT in inspiration improve the detection of solitary pulmonary nodules?

For optimal image fusion between CT and F-18-FDG-PET, the acquisition of CT images is performed in mild expiratory suspension, which might compromise the detection of lung metastases. This study aimed at evaluating the influence of expiration on the detection of solitary pulmonary nodules (SPN) and at assessing if additional inspiratory low-dose CT (I-LDCT) of the chest can improve the detection of potential lung metastases performing whole-body 16-channel PET-CT. Sixty-six patients with malignant tumors underwent PET-CT: contrast-enhanced CT was acquired during mild expiration and was used for fusion with PET images; additionally, chest I-LDCT was performed at deep inspiration. Two radiologists reported all SPN detected at I-LDCT and the expiratory CT scan independently. Overall, 53% of 128 SPN (mean: 3.8+/-0.2 mm) were detected at both respiratory states: 51 SPN only at I-LDCT, and 9 nodules only at expiratory CT. Of the SPN, 117/128 were classified as certain; 45 of those were additionally detected at I-LDCT, and 6 nodules at expiratory CT. A 100% detection rate was reached in SPN >4 mm at I-LDCT versus >8 mm at expiratory CT (all P<0.001). Additional I-LDCT of the chest significantly improves the detection of SPN at whole-body F-18-FDG-PET-CT and thus is recommended as part of the standard protocol for oncological patients.

Adult↗

PubMed2006

[CT-based software-supported prediction of the postoperative lung function after partial resection of the lung].

PURPOSE: The predicted postoperative forced exspiratory volume in one second (FEV (1)) is an important functional factor for predicting the operability of patients with bronchial carcinoma. A software tool that uses a preoperative chest MSCT and pulmonary function test (PFT) for largely automated prediction of the FEV (1) was evaluated. MATERIALS AND METHODS: Fifteen patients with surgically treated lung cancer were examined with a preoperative chest MSCT (1.25 mm slice thickness, 0.8 mm reconstruction increment) and PFT before and after surgery. CT scans were analyzed by the prototype software MeVisPulmo (MeVis gGmbH, Bremen) that predicted the postoperative FEV (1) as a percentage of the preoperative values measured by PFT. The automated segmentation and volumetry of lung lobes were performed either without or with minimal user interaction. Patients underwent lobectomy in twelve cases (6 upper lobes, 1 middle lobe, 5 lower lobes) and pneumectomy in three cases. The predicted FEV (1) values were compared to the observed postoperative values as a standard of reference. The additional functional parameters "total lung capacity" (TLC) and "forced vital capacity" (FVC) were compared to the FEV (1) results. RESULTS: Automated calculation of predicted postoperative lung function was successful in all cases. Due to an implausible PFT, two of the 15 patients were excluded from the collective. A mean postoperative FEV (1) value of 75 % (SD +/- 12 %) of the preoperative FEV (1) was calculated and 74 % (SD +/- 12 %) was actually measured. The deviations of the predicted value from the measured postoperative FEV (1) ranged between - 289 ml (-12 % of the measured postoperative FEV (1)) and + 294 ml (+ 15 % of the postoperative FEV (1)). The mean deviation (absolute value) was 137 +/- 77 ml/s. This corresponds to 7 +/- 3 % of the measured postoperative FEV (1). Bland-Altman-Statistics showed the 95 % "limits of agreement" for the predicted FEV (1) values to be between - 341 ml and + 301 ml, corresponding to - 17.5 % and + 15.8 of the measured postoperative FEV (1) value. Analysis of the TLC and FVC yielded similar results. CONCLUSION: In the present pilot study the software-assisted prediction of the postoperative FEV (1) using a preoperative MSCT and pulmonary function test corresponded satisfactorily with the observed postoperative values. The introduced approach may make it possible to obtain additional information for the prediction of functional operability prior to performing lung cancer surgery.

Adenocarcinoma↗

PubMed2005

Correlation between respiration-induced thoracic expansion and a shift of central structures.

The fusion of computed tomography (CT) and positron emission tomography (PET) may improve diagnostic accuracy, but is limited by different breathing protocols. This study aimed at quantifying respiration-induced alignment errors. PET-CT was acquired in 24 patients. Contrast-enhanced whole-body CT was obtained in a single breath hold in the expiratory state of a normal breathing cycle. An inspiratory low-dose CT of the thorax was acquired in the same session, and comparison of the two CT scans was used to assess the potential mismatch of PET and CT fusion. The largest craniocaudal expansion was found in the area of the diaphragm. A considerable sagittal expansion was found in the anterior parts of the lungs. Central tracheo-bronchial structures were displaced during inspiration mainly in the anterior and caudal directions. The craniocaudal shift of central structures showed a linear correlation with the diaphragmatic expansion, whereas the sagittal shift correlated with the sagittal pleural expansion. There was, however, no correlation between craniocaudal and sagittal respiratory motion. Alignment errors are most severe in the base of the lung, but central structures are affected, too. Understanding of the main vectors of respiratory motion may help in image interpretation when PET and CT are acquired separately.

Artifacts↗

PubMed2005

Negative ultrasound findings in patients with cervical artery dissection. Negative ultrasound in CAD.

BACKGROUND: Cervical artery dissection (CAD) is a common cause of ischemic stroke in the younger age group. Modern imaging techniques allow the depiction of the mural hematoma, even in CADs with only subtle vessel alterations. The aim of this retrospective study was (1) to characterize the angiological features in CAD and (2) to determine the frequency of initially normal ultrasonography (US) findings. METHODS: 86 patients aged 44 +/- 11 years with CAD of the internal carotid (ICA), (n = 55) or the vertebral artery (VA), (n = 31), admitted to our hospital within 8 days (mean 1.6 days) of symptom onset, were included. CAD was confirmed either by CT-angiography, MRI of the neck, MR-angiography or digital substraction angiography (DSA) and was compared with the results of the initial as well as repeated US examinations of the arteries supplying the brain. RESULTS: In 75 patients (81.2 %) signs of vessel stenosis or occlusion were found while 11 patients (12.8%) with CAD of the ICA (n = 9) and the VA (n = 2) had normal US findings. The site of dissection in the US negative patients was highly variable without a predilection site. In 2 of 7 patients with repeated US examinations, complete vessel occlusion was found on follow-up, while in 5 patients again normal results were found. In four patients, there were changing findings in two alternative confirming imaging methods (MRI/DSA, CT/MRI) and in one patient conflicting findings (CT/MRI). Brain infarctions had occurred in 7 of the initially sonographically normal patients while the other 4 had suffered from transient (n = 2) or local (n = 2) symptoms only. CONCLUSION: Approximately 1 out of 8 patients with subsequently proven CAD has negative initial neurovascular US findings despite comprehensive examination. In patients with suspected CAD and negative US examination, repeated US examinations and further diagnostic imaging, especially MRI is necessary.

Adult↗

PubMed2005

Dehydration confounds the assessment of brain atrophy.

Computerized brain volumetry has potential value for diagnosis and the follow-up evaluation of degenerative disorders. A potential pitfall of this method is the extent of physiologic variations in brain volume. The authors show that dehydration and rehydration can significantly change brain volume: lack of fluid intake for 16 hours decreased brain volume by 0.55% (SD, +/-0.69), and after rehydration total cerebral volume increased by 0.72% (SD, +/-0.21).

Adult↗

PubMed2005

[Comparison of a T1-weighted inversion-recovery-, gradient-echo- and spin-echo sequence for imaging of the brain at 3.0 Tesla].

PURPOSE: The increased T1 relaxation times at 3.0 Tesla lead to a reduced T1 contrast, requiring adaptation of imaging protocols for high magnetic fields. This prospective study assesses the performance of three techniques for T1-weighted imaging (T1w) at 3.0 T with regard to gray-white differentiation and contrast-to-noise-ratio (CNR). MATERIALS AND METHODS: Thirty-one patients were examined at a 3.0 T system with axial T1 w inversion recovery (IR), spin-echo (SE) and gradient echo (GE) sequences and after contrast enhancement (CE) with CE-SE and CE-GE sequences. For qualitative analysis, the images were ranked with regard to artifacts, gray-white differentiation, image noise and overall diagnostic quality. For quantitative analysis, the CNR was calculated, and cortex and basal ganglia were compared with the white matter. RESULTS: In the qualitative analysis, IR was judged superior to SE and GE for gray-white differentiation, image noise and overall diagnostic quality, but inferior to the GE sequence with regard to artifacts. CE-GE proved superior to CE-SE in all categories. In the quantitative analysis, CNR of the basal ganglia was highest for IR, followed by GE and SE. For the CNR of the cortex, no significant difference was found between IR (16.9) and GE (15.4) but both were superior to the SE (9.4). The CNR of the cortex was significantly higher for CE-GE compared to CE-SE (12.7 vs. 7.6, p < 0.001), but the CNR of the basal ganglia was not significantly different. CONCLUSION: For unenhanced T1 w imaging at 3.0 T, the IR technique is, despite increased artifacts, the method of choice due to its superior gray-white differentiation and best overall image quality. For CE-studies, GE sequences are recommended. For cerebral imaging, SE sequences give unsatisfactory results at 3.0 T.

Brain↗

PubMed2005

[Is the Canadian CT head rule for minor head injury applicable for patients in Germany?].

PURPOSE: To evaluate the applicability of the Canadian CT Head Rule (CCHR) on head trauma patients in a German university hospital. METHODS: 122 patients (m = 74; f = 48; 40 +/- 19 years) were examined with cranial CT due to minor head trauma. The need for cranial CT according to the CCHR was evaluated retrospectively. RESULTS: With a sensitivity of 98.9 % and a specificity of 46.6 % all patients with the need for neurosurgical intervention were detected by applying the major criteria of the CCHR. Also, every patient with severe brain injury was detected by the extended criteria with a sensitivity of 99.6 % and a specificity of 34.1 %. This would have led to a reduction in the rate of cranial CT examinations by 45.1 % for the major and 22.1 % for the extended criteria. No patient with severe brain injury would have been missed by application of the criteria. CONCLUSION: The Canadian CT Head Rule for patients with minor head trauma is applicable with a very high sensitivity and the potential of significantly reducing the rate of cranial CT examinations in these patients.

Accidental Falls↗

PubMed2005

[The "EVA" Trial: Evaluation of the Efficacy of Diagnostic Methods (Mammography, Ultrasound, MRI) in the secondary and tertiary prevention of familial breast cancer. Preliminary results after the first half of the study period].

PURPOSE: To investigate the respective diagnostic accuracies of the different breast imaging modalities, i. e., mammography (Mx), high-frequency breast ultrasound (US), and dynamic contrast-enhanced breast (MRI) regarding the early diagnosis of familial (hereditary) breast cancer. MATERIALS AND METHODS: A prospective, non-randomized controlled clinical multi-center trial is performed at 4 academic tertiary care centers in Germany (Ulm, Munchen/Grosshadern, Munster and Bonn) for a total period of 4 years, sponsored by the German Cancer Aid. The protocol consists of semiannual clinical visits and breast ultrasound, and annual bilateral two-view Mx, US and MRI. Imaging studies were first analyzed independently, then Mx was read in conjunction with US, followed by Mx combined with MRI, and finally, all three imaging modalities were read in synopsis. We present the concept and first results of this trial. RESULTS: So far, 748 screening rounds are available for analysis in 613 women. A total of 12 breast cancers have been identified, with 11/12 cases in the pTis or pT1/N0 stage. The mean size of detected invasive cancers was 7 mm. A total of 19 benign lesions were biopsied due to false-positive imaging diagnoses. The breast cancer detection rates were: Mx: 5/12 (42 %), US 3/12 (25 %), MRI 10/12 (83 %), and the positive predictive values: Mx 5/17 (29 %), US 3/15 (30 %), and MRI 10/23 (43 %). CONCLUSION: The preliminary data suggest that early diagnosis of familial breast cancer is feasible by intensified surveillance, in particular with the addition of MRI.

Adult↗

PubMed2005

[Incidence of cerebral ischemia in patients with suspected cervical artery dissection: first results of a prospective study].

PURPOSE: Aim of this prospective study was to investigate the incidence of spontaneous cervical artery dissection (sCAD) and cerebral ischemia in patients with suspected sCAD by using a combined head-neck MR-imaging protocol. MATERIALS AND METHODS: 51 consecutive patients (24 m, 27 f, mean age 39.5 years, range 18 - 55 yrs) admitted to our stroke unit with suspected sCAD according to clinical criteria and age < 55 years underwent a combined head and neck MR examination within 24 hours of admission (Gyroscan Intera 1.5 T, Philips). Head MRI included ax FLAIR, ax T (1), ax DWI and TOF angiography (imaging time 12 min). Neck MRI consisted of ax T1w-TSE, T2w-TSE, contrast enhanced T1w-TSE and CE-MRA (imaging time 17 min). Three radiologists assessed both studies in consensus with regard to the presence of sCAD and acute ischemia. RESULTS: One patient had to be excluded because of motion artefacts. In 17 of 50 patients sCAD was diagnosed, and in 20 of 50 patients cerebral ischemia. In 5 patients cerebral ischemia was caused by sCAD. CONCLUSION: The proposed combined MR protocol allows imaging work-up of patients with suspected sCAD within approximately 30 min, resulting in conclusive information about the status of the extracranial vasculature and the presence of ischemia. The high incidence of patients with definite sCAD and the low incidence of cerebral ischemia indicates the necessity of an early definite diagnosis in order to start timely anticoagulation to prevent development of stroke.

Acute Disease↗

PubMed2005

Staging in childhood lymphoma: differences between FDG-PET and CT.

AIM: The clinical value of positron emission tomography using fluorine-18 fluoro-deoxy-glucose (FDG-PET) in the staging of adult lymphoma has been shown in many studies. However, there are only few data regarding childhood lymphoma. The purpose of this retrospective study was to compare the staging of childhood lymphoma using FDG-PET and the established computed tomography (CT). METHOD: Whole-body FDG-PET was performed in 25 children with histologically proven Hodgkin's disease (n = 18) and non-Hodgkin's lymphoma (n = 7) using a dedicated PET. The findings were compared with the CT results. Both examinations, FDG-PET and CT, were assessed by two experienced physicians. In each patient, 30 regions were analysed (22 nodal, 8 extranodal). Each region was assessed using a five value scale (definitely/probably positive, equivocal, probably/definitely negative). RESULTS: 662 regions (470 nodal, 192 extranodal) were compared. 91 regions (81 nodal, 10 extranodal; 14%) were concordant positive and 517 regions (347 nodal, 170 extranodal; 78%) were concordant negative. In 47 regions, 48 discordant findings (7%) were described: 27 findings (22 nodal, 5 extranodal) were positive using FDG-PET and negative using CT whereas 21 findings (17 nodal, 4 extranodal) were positive using CT and negative using PET. A total of 7 regions (1%) were judged equivocal in one imaging modality (1 FDG-PET, 6 CT). Using FDG-PET as compared to CT, resulted in a higher staging in 4 of 25 patients and in a lower staging in 2 of 25 patients. CONCLUSION: Staging of childhood lymphoma using FDGPET shows differences compared with CT resulting in a different staging in 6 of 25 patients. Prospective studies are required to evaluate the impact of these discrepancies on the clinical management of pediatric patients.

Adolescent↗

PubMed2004

Real time fMRI: a tool for the routine presurgical localisation of the motor cortex.

In patients with brain lesions adjacent to the central area, exact preoperative knowledge of the spatial relation of the tumour to the motor cortex is of major importance. Many studies have shown that functional magnetic resonance imaging (fMRI) is a reliable tool to identify the motor cortex. However, fMRI data acquisition and data processing are time-consuming procedures, and this prevents general routine clinical application. We report a new application of real time fMRI that allows immediate access to fMRI results by automatic on-line data processing. Prior to surgery we examined ten patients with a brain tumour adjacent to the central area. Three measurements were performed at a 1.5-T Magnetom Vision Scanner (Siemens, Forchheim, Germany) on seven patients and at a 1.5-T Intera Scanner (Philips, Best, The Netherlands) on three patients using a sequential finger-tapping paradigm for motor cortex activation versus at rest condition. Blood oxygen level-dependant (BOLD) images were acquired using a multislice EPI sequence (16 slices, TE 60, TR 6000, FOV 210x210, matrix 64x64). The central sulcus of the left hemisphere could be clearly identified by a maximum of cortical activity after finger tapping of the right hand in all investigated patients. In eight of ten patients the right central sulcus was localised by a signal maximum, whereas in two patients the central sulcus could not be identified due to a hemiparesis in one and strong motion artefacts in the second patient. Finger tapping with one side versus rest condition seems to result in more motion artefacts, while finger tapping of the right versus the left hand yielded the strongest signal in the central area. Real time fMRI is a quick and reliable method to identify the central sulcus and has the potential to become a clinical tool to assess patients non-invasively before neurosurgical treatment.

Adult↗

PubMed2004

Sensitivity of T2-weighted FSE sequences towards physiological iron depositions in normal brains at 1.5 and 3.0 T.

To evaluate the sensitivity of T2-weighted fast spin-echo (FSE) sequences to physiological iron depositions in normal brains at MR imaging field strengths of 1.5 and 3.0 T. T2-weighted FSE sequences acquired at 1.5 and 3.0 T clinical imaging systems (Gyroscan Intera, Philips Medical Systems, Best, The Netherlands) were compared by means of MRI in phantoms ( n=6) and healthy volunteers ( n=10). Contrast-to-noise ratios (CNRs) of tubes doped with iron oxides at different concentrations and of brain areas with physiological iron depositions (nucleus ruber, substantia nigra, globus pallidus) were calculated for either field strength. Apparent susceptibility effects of iron-containing brain structures were qualitatively analyzed by comparing the degree of visible hypointensity by a score system at either field strength. The mean CNR of iron oxide tubes and iron-containing brain areas was significantly decreased at 3.0 T. Qualitative analysis confirmed these measurements. Detection and diagnosis of brain disorders with altered iron content such as neurodegenerative parkinsonian disorders (NPD) or intracerebral hemorrhage should benefit from the increased sensitivity of T2-weighted FSE sequences to susceptibility effects at 3.0 T.

Brain↗

PubMed2004

N-acetylaspartate levels of left frontal cortex are associated with verbal intelligence in women but not in men: a proton magnetic resonance spectroscopy study.

The left frontal cortex plays an important role in executive function and complex language processing inclusive of spoken language. The purpose of this work was to assess metabolite levels in the left and right prefrontal cortex and left anterior cingulum by proton magnetic resonance spectroscopy and relate results to verbal intelligence (Wechsler Adult Intelligence Scale revised) in a sample of college-educated healthy volunteers (dorsolateral prefrontal cortex [DLPFC]: n=52, 23 females, and left anterior cingulum: n=62, 22 females; age range: 20-75 years). In women only, N-acetylaspartate in the DLPFC and in the left anterior cingulate cortex was positively correlated with vocabulary scores. Our data support the hypothesis of existing gender differences regarding the involvement of the left frontal cortex in verbal processing as reflected in different correlations of specific metabolites with verbal scores.

Adult↗

PubMed2004

[Clinical evaluation of a software for automated localization of lung nodules at follow-up CT examinations].

PURPOSE: To evaluate a software algorithm for automated localization of pulmonary nodules at follow-up CT examinations of the chest and to determine factors influencing the rate of correctly matched nodules. MATERIALS AND METHODS: The "real-time automatic matching" (RAM) algorithm (Siemens LungCare trade mark software) was applied to 22 follow-up multirow-detector CT (MDCT) examinations in 11 patients (Siemens Somatom VolumeZoom, tube voltage 120 kVp; effective tube current 20 mAs (n = 18) or 100 mAs (n = 4); 4 x 1 mm detector configuration, 1.25 mm slice thickness; 0.8 mm reconstruction increment; standard lung kernel B50f) with a total of 190 lung nodules (mean diameter 6.7 +/- 3.5 mm, range 2 - 17 mm). The following nodule features were recorded: diameter, edge definition (well- or ill-defined), location (upper, middle or lower third; central or peripheral; right or left lung) and inspiration level (considered identical if the difference of diaphragm-apex distance between baseline and follow-up examination was < 5 %, otherwise it was considered different). A nodule was regarded as correctly localized if the marking box drawn by the software was visible on at least one slice together with the nodule and the center of the nodule was located inside the marking box. chi(2)-test was used to describe influence of nodule features on detection rate. Influence of nodule size was assessed using Mann-Whitney-U-Test. RESULTS: RAM correctly located 164 of 190 of all lung nodules (86.3 %). Detection rate did not depend on nodule location (left vs. right lung: p = 0.48; upper vs. middle vs. lower third: p = 0.96; peripheral vs. central: p = 0.47) or diameter (p = 0.30). Influence of inspiration level was highly significant (p < 0.001): nodules were detected in 100 % (146/146) for identical inspiration levels and in 40.9 % (18/44) for different inspiration levels. The observation of a significant better localization of ill-defined nodules (p = 0.028) corresponds to a statistical artifact due to the inhomogeneous distributions of this specific feature in our data. CONCLUSION: RAM is a valuable tool for follow-up of lung nodules at CT. Only very different inspiration levels influenced detection rate.

Algorithms↗

PubMed2004

Diagnostic performance of a commercially available computer-aided diagnosis system for automatic detection of pulmonary nodules: comparison with single and double reading.

OBJECTIVE: To assess the diagnostic performance of a commercially available computer-aided diagnosis (CAD) system for automatic detection of pulmonary nodules with multi-row detector CT scans compared to single and double reading by radiologists. MATERIALS AND METHODS: A CAD system for automatic nodule detection (Siemens LungCare NEV VB10) was applied to four-detector row low-dose CT (LDCT) performed on nine patients with pulmonary metastases and compared to the findings of three radiologists. A standard-dose CT (SDCT) was acquired simultaneously and used for establishing the reference data base. The study design was approved by the Institutional Review Board and the appropriate German authorities. The reference data base consisted of 457 nodules (mean size 3.9 +/- 3.1 mm) and was established by fusion of the sets of nodules detected by three radiologists independently reading LDCT and SDCT and by CAD. An independent radiologist used thin slices to eliminate false positive findings from the reference base. RESULTS: An average sensitivity of 54 % (range 51 % to 55 %) was observed for single reading by one radiologist. CAD demonstrated a similar sensitivity of 55 %. Double reading by two radiologists increased the sensitivity to an average of 67 % (range 67 % to 68 %). The difference to single reading was significant (p < 0.001). CAD as second opinion after single reading increased the sensitivity to 79 % (range 77 % to 81 %), which proved to be significantly better than double reading (p < 0.001). CAD produced more false positive results (7.2 %) than human readers but it was acceptable in clinical routine. CONCLUSION: Double reading with CAD as second reader offered a significantly increased sensitivity compared to conventional double reading. Thus, CAD is a valuable tool for the detection of pulmonary nodules and should be used as second opinion.

Adult↗

PubMed2004

[Automatic injectors in magnetic resonance imaging and computed tomography: pilot study on hygienic aspects].

PURPOSE: To evaluate hygienic conditions using automatic injectors in magnetic resonance imaging (MRI) and computed tomography (CT) during clinical routine. MATERIALS AND METHODS: The surfaces of medical devices (e. g., control console) and the palms of the technical and medical staff were microbiologically analyzed by taking imprints before and after hygienic education. In addition, the injector syringes for contrast medium (CM) and saline were checked for microbiological contamination following multiple (MRI: 14 h; CT 8 h) and single use. Furthermore, the potential of retrograde contamination from the patient along the tube was analyzed. RESULTS: A bacterial contamination with typical dermal bacteria was documented for the surfaces of the medical devices, the palms of the technical and medical staff, and the injection syringes following multiple use (MRI: 10/10 CM syringes, 6/10 saline syringes; CT: 8/10 CM syringes, 5/10 saline syringes). Correct hand disinfection in combination with single use of syringes avoided bacterial colonization. Retrograde bacterial contamination from the patient was not observed. CONCLUSION: Regular hygienic teaching sessions for technical and medical staff in MRI and CT departments using automatic injectors should be mandatory. Furthermore, the multiple use of syringes should be avoided until investigations addressing the potential of bacterial contamination are performed.

Contrast Media↗