IDAC-ALPHA: AN ALPHA DOSIMETRY SOFTWARE FOR NORMAL ORGANS AND TISSUES.

Radiopharmaceuticals have been used for the treatment of various forms of cancer since the 1940s. In recent years, the advantages of alpha emitting radionuclides have emerged as a favourable treatment option. However, most alpha emitting radionuclides have long decay chains with long-lived daughter radionuclides. This leads to uncertainties in the dosimetry for normal organs and tissues, when established dosimetry models are employed. The aim of this project is to assign each progeny its own biokinetic behaviour. The novel dosimetry model was applied to 223Ra-dichloride, frequently used for the treatment of patients with metastatic bone disease from castration-resistant prostate cancer. In this dosimetry model, individual biokinetics for each daughter radionuclide was included. This resulted in a decrease in absorbed dose to bone surfaces and red marrow and increased absorbed dose to liver and kidney, when compared with dosimetry models assuming that the daughter nuclides follow the biokinetics of the parent radionuclide.

[From reconstruction to function : Hands-on training in tympanoplasty using real-time feedback]. / Von der Rekonstruktion zur Funktion : Tympanoplastik-Training mit Real-Time-Feedback.

BACKGROUND: Surgery of the middle ear requires a very high level of fine motor skills. Due to the increased potential for complications in middle ear operations, it is appropriate to acquire these skills beforehand by operating on a model. OBJECTIVE: How satisfactory is the training on suitable models? Are the skills acquired from working on a model transferable to intraoperative situations? Will the type of model and its use for training influence ear surgery in the future? MATERIAL AND METHODS: Available publications and own experiences with the Dresden tympanoplasty model (DTM) are analyzed and discussed. RESULTS: Although middle ear surgery makes very high demands on the surgeon and there is a significant risk for severe complications to the ear as a sense organ, there are currently very few options to train surgeons in advance. The DTM is a validated training model, which is capable of closing this gap. Due to the possibility of using a real-time feedback variation of the model, the understanding for reconstruction quality and intraoperative acoustic stress can be improved. The translation of the real-time feedback idea into actual middle ear surgery can improve reconstruction quality in the future. CONCLUSION: Training on suitable models is indispensable, especially when training as a surgeon to carry out middle ear operations. Adding another sense perception to the internal and external quality assessment of tympanoplasty by inclusion of the real-time feedback option, can optimize learning and operating processes.

[Spectroscopic investigation of the middle ear mucosa]. / Spektroskopische Untersuchung der Mittelohrschleimhaut.

BACKGROUND: The middle ear mucosa (MEM) plays a central role in the middle ear due to its function of providing regular ventilation. To date, assessment of the state of the MEM is only possible subjectively by the surgeon. An objective characterization of the state of the MEM is desirable. OBJECTIVE: The aim of this study was to enable objective characterization of the MEM and test infrared (IR) spectroscopy as a possible diagnostic tool for clinical use. MATERIALS AND METHODS: During middle ear surgery, 48 MEM samples were collected and divided into four groups according to clinical appearance: group I: normal MEM; group II: sclerotic MEM; group III: inflammatory thickened MEM; group IV: granulated MEM. After collection, samples were analyzed by IR spectroscopy to identify characteristic IR spectra. RESULTS: In the supervised analysis of the selected images, the biochemical differences representing the decisive factors for classification into groups I to IV were characterized. The differences in amide bands, carbohydrates, lipids, and proteins permit reliable separation of the clinical categories. CONCLUSION: Spectroscopic investigations enable objective characterization of the MEM. Conclusions regarding biochemical differences make it possible to weigh up treatment options. Routine use of IR spectroscopy in the operating theater requires histopathological comparison and an extended dataset with reference values of the individual groups.

Robotic stereotactic ablative radiotherapy for renal cell carcinoma in patients with impaired renal function.

BACKGROUND: Robotic stereotactic ablative radiotherapy (SABR) is currently under investigation as a noninvasive treatment option for patients with renal cell carcinoma (RCC). For radiation therapy of RCC, tumor motion and the need for high ablative doses while preserving the remaining renal parenchyma is a challenge. We aimed to analyze the safety and efficacy of robotic radiosurgery in RCC in a specific difficult subgroup of patients with impaired renal function. METHODS: We retrospectively identified all patients with RCC, treated with robotic SABR and motion compensation in our institution between 2012 and 2017. Either single fraction SABR of 24 or 25 Gy or 3 fractions of 12 Gy prescribed to the 70% isodose line was applied. Local control, overall survival, radiation side effects were evaluated together with renal function and tumor motion. RESULTS: We analyzed data of 13 lesions treated in 10 patients with clear cell RCC and a mean age of 70.5 ± 13.6 years (range: 48-87). Prior to SABR, 8 patients underwent previous complete and/or partial nephrectomy, 7 patients presented with chronic kidney disease ≥ stage 3. The median of minimum, mean and maximum planning target volume doses were 23.2, 29.5 and 35.0 Gy for single fraction and 24.4, 42.5 and 51.4 Gy for the three fractions regime. Persistent local control by robotic SABR was achieved in 9 out of 10 patients (92.3% of all lesions) within a median follow-up period of 27 month (range: 15-54). One patient underwent nephrectomy due to progressive disease and sufficient renal function of the contralateral kidney. Renal function remained stable with a mean estimated glomerular filtration rate (eGFR) of 51.3 ± 19.7 ml/min at baseline and 51.6 ± 25.8 ml/min at follow-up. The largest respiratory-induced tumor motion was seen in superior-inferior direction, compensated by the CyberKnife with mean targeting errors of maximal 2.2 mm. CONCLUSIONS: Robotic SABR is technically feasible for the treatment of RCC in preexisting kidney disease with good local tumor control at about 2 years follow-up. Robotic SABR with motion tracking offers a valid treatment option for patients, who are at increased risk for progression to end-stage renal disease due to partial nephrectomy or ablative techniques.

[Hiatus hernia : Standards and controversies in diagnostics and treatment]. / Hiatushernie : Standards und Kontroversen in Diagnostik und Therapie.

A hiatus hernia is defined as a transdiaphragmatic protrusion/migration of the intrabdominal contents through the esophageal hiatus of the diaphragm. The classification of hiatus hernias is based on anatomical morphological differentiation (types I-IV). The leading symptoms and psychological stress vary with respect to the symptoms, e. g. reflux and compression symptoms. Gastroscopy and multichannel intraluminal impedance pH measurement are obligatory preoperative functional diagnostics. A distinction is made between frequent type I hernia (antireflux surgery), symptomatic paraesophageal, thoracic and mixed hernia types (II-IV). Surgical indications exist in symptomatic type II-IV hernias. Hiatal mesh augmentation reduces recurrences. The complication potential of synthetic meshes must be taken into account. Biological implants show no advantages.

Learning while multitasking: short and long-term benefits of brain stimulation.

We employed a simulated production task that mimics the real-world skill acquisition required of operators working in control rooms of power plants to assess short and long-term effects of transcranial random noise stimulation (tRNS). tRNS has shown potential for enhancing learning and performance of cognitive skills. Forty subjects (24 female) learned how to execute the simulated production task during the training phase and were required to perform a secondary task during the skill acquisition phase while they received active (12 min) or sham tRNS on DLPFC. After 2 weeks they had to recall the task again without any stimulation. The results demonstrate that tRNS promoted better multitasking as reflected by better performance in a secondary task during and immediately after tRNS. However, 2 weeks later, beneficial effect of tRNS on retention was moderated by general mental ability. Particularly, tRNS benefited those with lower general mental ability. Practitioner summary: By using a simulated production task, we assessed the effects of tRNS on learning and skill retention. The study indicates that neurostimulation can enhance the learning of multiple complex tasks. Moreover, it shows that retention of those tasks can be supported by neurostimulation, especially for those with lower general mental ability.

[Medial Unicompartmental Knee Arthroplasty Using Patient-Specific Instrumentation - Accuracy of Preoperative Planning, Time Saving and Cost Efficiency]. / Unilaterale mediale Schlittenprothesen mit patientenspezifischer Instrumentierung - Planungsgenauigkeit, Zeitersparnis und Kosteneffektivität.

BACKGROUND: In the past few years, patient-specific instrumentation (PSI) in knee endoprosthetics has been energetically marketed. PSI can enhance the accuracy of the size and alignment of the prosthesis components. It should also be possible to reduce hospital costs and operating time. It remains unclear whether these putative advantages are achieved in medial unicompartmental knee arthroplasty (UKA). PATIENTS/MATERIAL AND METHODS: Data from 22 patients (24 knees) were analysed retrospectively. The focus was on the reliability of preoperative surgical planning - particularly with regards to the level of experience of the five surgeons involved, who were split into two groups depending on their level of experience, as defined by EndoCert®. Another focus was on the evaluation of actual surgical time and cost effectiveness using PSI. RESULTS: In order to achieve an optimal outcome, preoperative surgical planning had to be modified intraoperatively to a great extent. The femoral component had to be adjusted intraoperatively in 41.7 % of all cases, the tibial component in 58.3 % and the polyethylene insert in 87.5 %. Surgeons equipped with less experience had to change preoperative planning more often than the more experienced surgeons. Utilising PSI increased the operating time of both the less experienced and the more experienced surgeons. PSI planning and lack of surgical experience were the main predictors of increased surgical time. Instead of lowering costs, utilizing PSI increased surgical costs by nearly 1300 $ per case. This was due to increased operating time, license fees and extraordinary expenditure for MRI scans. CONCLUSION: The advertised advantages of PSI were not supported by the data analysed. On the contrary, this technology leads to additional costs, greater operating time and insufficient accuracy in preoperative planning. As not a single study has yet demonstrated better outcomes in terms of alignment and/or function with PSI than with standard instrumentation, additional data are required before PSI can be recommended for routine use in medial UKA.

Patient radiation protection covers for head CT scans - a clinical evaluation of their effectiveness.

PURPOSE: Although the use of thyroid shields for patients for head CT examinations is reasonable and even required by German regulations, so far available shields are often not used due to difficult applicability. New shields that are easier to use and therefore may gain wider acceptance and more frequent use are now available. In this work two new patient shields are investigated regarding their dose reduction effectiveness and applicability and compared to a thyroid/sternum shield typically used as a part of personal protective equipment. MATERIALS AND METHODS: The reduction of organ doses for thyroid, sternum and mamma were measured with thermoluminescence detectors in an anthropomorphic female phantom. Additionally, the influence of the length or position of the overview scan at the beginning of the CT examination was taken into account. RESULTS: Depending on the patient shield, a reduction of the organ doses for thyroid of 5 - 24 %, for sternum of 25 - 48 % and for mamma of 25 - 70 % could be found. A shift of 25 mm in the cranial direction for the overview scan resulted in a reduction of these organ doses of 12 - 15 %. CONCLUSION: Patient shields for cranial CT examinations provide a considerable dose reduction. New models are easily applied and no decrease in image quality through reconstruction artifacts could be found. Therefore, it is advised to use shields which are applied upon the patient without the need to be wrapped around the neck and the overview scan should be positioned as close as possible to the examined region. KEY POINTS: • New shields provide a compromise between usability and radiation protection.• Patient shields reduce organ doses even when not directly exposed.• The overview scan contributes considerably to out of field organ doses.• Shielding factors are greatly influenced by the positioning of the examination field.

[Vocational rehabilitation after total laryngectomy]. / Berufliche Rehabilitation nach Laryngektomie.

BACKGROUND: Aim of this study was to find out how many patients after a total laryngectomy (TLE) return to work successfully and what factors support vocational rehabilitation. PATIENTS AND METHODS: Laryngectomees (n=231) aged up to 60 years completed questionnaires and structured interviews before TLE (t1), before rehabilitation (t2), at the end of rehabilitation (t3), 1 year after TLE (t4), 2 years after TLE (t5), and 3 years after TLE (t6). RESULTS: Prior to TLE, 38% of all respondents were employed, 34% were unemployed, 23% received disability-related and 3% age-related pension retirement. One year after TLE, 13% were employed, 15% 2 years and 14% 3 years after TLE. Unemployed were 10% (t4), 5% (t5), and 7% (t6) of the patients. For 59% of all respondents it was very important to have a job. Predictors of successful vocational rehabilitation were employment prior to TLE, age <50 years, being self-employed or clerical employee, good physical functioning, good speech intelligibility, high motivation to go back to work, and support from colleagues. CONCLUSION: Only few laryngectomees return to work. However, even before TLE only a third of the patients was employed, another third was unemployed. Most of the patients receive pension retirement after TLE. As return to work is important for many patients, patient consultations should consider possibilities to support vocational rehabilitation before offering to apply for retirement.

Further evidence of pleiotropy influencing speech and language: analysis of the DYX8 region.

BACKGROUND/AIMS: Genetic studies have raised the possibility of common bases for cognitive linguistic disorders such as speech sound disorder (SSD), reading disorder (RD) and language impairment (LI). Thus, some of the same genes may jointly influence cognitive components within and between these three disorders. We examined the plausibility of this theory in a sample of families ascertained on the basis of a child with SSD. METHODS: Using the method of generalized estimating equations to solve a bivariate family predictive model we obtained measures of comorbidity and familial aggregation of SSD and LI. We then used two methods of multipoint model-free linkage analysis to evaluate SSD and LI psychometric test measures over a region previously implicated in linkage studies of RD, DYX8 region, 1p34-p36. RESULTS: Bivariate phenotypic analyses show evidence of comorbidity and within family aggregation and coaggregation of SSD and LI. In addition, two regions on chromosome 1 show suggestive evidence of linkage. The first region was previously reported in dyslexia studies. Our maximum linkage signal in this region measured articulation (p = 0.0009) in SSD sibling pairs. The second region is characterized by processes involved in language production, with the maximum linkage signal measuring listening comprehension (p = 0.0019) using all sibling pairs. CONCLUSION: We conclude that the DYX8 region could bear genes controlling pleiotropic effects on SSD, LI and RD.

Pulmonary perfusion in acute pulmonary embolism: agreement of MRI and SPECT for lobar, segmental and subsegmental perfusion defects.

PURPOSE: To assess prospectively the agreement of magnetic resonance (MR) pulmonary perfusion with single-photon emission computed tomography (SPECT) perfusion for perfusion defects down to the subsegmental level in patients with suspected pulmonary embolism (PE). MATERIAL AND METHODS: In 41 patients with suspected PE, contrast-enhanced MR pulmonary perfusion (3D-FLASH, TR/TE 1.6/0.6 ms) was compared to SPECT perfusion on a per-examination basis as well as at the lobar, segmental, and subsegmental level. RESULTS: The MRI protocol was completed in all patients, and mean examination time was 3 min 56 s. MR perfusion showed a very high agreement with SPECT (kappa value per examination 0.98, and 0.98, 0.83, and 0.69 for lobar, segmental, and subsegmental perfusion defects, respectively). Of 15 patients with PE, MR perfusion detected 14 cases. CONCLUSION: The very high agreement of MR perfusion with SPECT perfusion enables the detection of subtle findings in suspected PE.

[Improvement of anxiety and depression in women with breast cancer during inpatient oncological rehabilitation-- results of a prospective study]. / Verbesserung von Angst und Depression bei Brustkrebspatientinnen während stationärer onkologischer Rehabilitation-- Ergebnisse einer prospektiven Studie.

PURPOSE: Investigation of the influence of an oncological inpatient rehabilitation programme on anxiety and depression in women with breast cancer. PATIENTS AND METHOD: 198 women with breast cancer, aged 25 to 75 years, filled in the Hospital Anxiety and Depression Scale (HADS) German version at the beginning and end of inpatient rehabilitation. Focus was set on the frequency of anxiety and depression. Therefore proportions with 95 % confidence intervals (CI) were built. The before-after comparison of HADS-scores was made using the signed rank test with two-sided level of significance of alpha = 5 %. In addition effect sizes were calculated. Possible relations between the scores at the beginning of rehabilitation and the patients' age or the interval since diagnosis were analysed by calculating correlation coefficients. RESULTS: At the beginning of rehabilitation a state of anxiety was probable in 23.2 % (CI [17.3 %; 29.1 %] of the women and one of depression in 9.1 % (CI [5.8 %; 13.9 %]). In other words, they reached a level of >or= 11 score points on each scale. No correlation was found with the age of the patients or the time interval since diagnosis (|r|

The pharmacokinetics of zinc from zinc gluconate: a comparison with zinc oxide in healthy men.

OBJECTIVE: Zinc supplementation is beneficial in some clinical conditions such as age-related macula degeneration (AMD). It has been suggested that zinc absorption is influenced by the form in which zinc is ingested. Therefore, the pharmacokinetics of zinc gluconate (organic) were compared with those of zinc oxide (inorganic). METHODS: 12 healthy male subjects aged between 21 and 31 years (24 years median) orally received daily doses of 20 mg metal zinc as zinc gluconate and 17.4 mg metal zinc as zinc oxide under randomized crossover conditions for 14 days each with at least 14 days as a washout. Zinc plasma concentrations were measured by means of inductively coupled plasma-atomic emission spectroscopy. RESULTS: C(max) was found 18.3% (10.3 - 26.3%) higher following multiple-dose administration of zinc gluconate as compared to zinc oxide (mean; 0.95% confidence interval of the relative differences between both treatment conditions; p < 0.05). AUC(0-24h) was noted 8.1% (1.9 - 14.3%) higher after zinc was given as zinc gluconate when compared to zinc oxide (p < 0.05) whereas t(max) did not differ between both treatment conditions. CONCLUSIONS: Zinc absorption in humans could be improved by zinc complexation with gluconate.

[Thoracic real-time MRI: experience from 2200 examinations in acute and ill-defined thoracic diseases]. / Thorakale Echtzeit-MRT: Erfahrungen aus 2200 Untersuchungen bei akuten und unklaren thorakalen Erkrankungen.

PURPOSE: To retrospectively assess the indication for thoracic real-time MRI, demonstrate typical findings, analyze the diagnostic potential in subgroups with suspected pulmonary embolism (PE) and aortic dissection (AD), and describe the influence of real-time MRI on the role of MRI in acute thoracic diseases. MATERIALS AND METHODS: From July 2001 to February 2005, real-time MRI was applied in 2,256 examinations in 1,714 patients. MRI was the primary diagnostic modality for these thoracic diseases as computed tomography has been available only since 2003. Characteristics of the TrueFISP sequence applied were: TR/TE/flip angle 3.1 ms/1.6 ms/59 degrees , respectively. FOV 340 - 360 mm, matrix size 156 to 192 x 256 pixels, slice thickness 3 to 4 mm, slices overlapped by 50 %. Acquisition time was 0.4 to 0.5 s per image. Three hundred and twenty transverse, coronal and sagittal images were acquired in three minutes. No breath holding, and only minimal patient cooperation, was required. Turbo-spin-echo sequences as well as ECG-gated and contrast-enhanced sequences were added depending on the indication. RESULTS: Most common indications were: acute thoracic nonspecified disease (n = 276, 12.24 %), PE (n = 573, 25.4 %), bleeding (n = 154, 6.8 %), AD (n = 222, 9.8 %), topographic information in complex findings (n = 654, 29.0 %). Real-time MRI was the sole MRI technique applied in 180 examinations (8.0 %), ECG-gated real-time MRI was applied in 87 examinations and breath hold was used in 107 examinations. PE was diagnosed in 181 examinations; reference techniques (MRI, computed tomography, single photon emission computed tomography) confirmed 170 of these and detected 19 more cases (sensitivity 90.0 %, specificity 97.1 %). Real-time MRI detected 141 suspected AD and 53 more nonsuspected AD. Of these, 191 were confirmed by other MRI techniques, surgery or clinical course (98.5 %). Real-time MRI coincidentally detected 56 pulmonary tumors, all were confirmed with computed tomography. Thus, especially vascular diseases could be easily assessed with real-time MRI, while computed tomography had advantages in the evaluation of the lung parenchyma. CONCLUSION: Real-time MRI both enables emergency MRI examinations for thoracic diseases in clinical patients in unstable condition and allows an explorative style of working in patients with nondefined acute thoracic diseases.

Ankylosing spondylitis and bone mineral density--what is the ideal tool for measurement?

Ankylosing spondylitis (AS) is characterised by chronic inflammation and partial ossification, yet vertebral fractures due to osteoporosis, although common, are frequently unrecognised. The aim of this study was to (1) show the frequency of changes in the progress of osteopenia/osteoporosis in AS depending on duration and stage of the disease and (2) assess the ranking of two different methods of bone density measurement in this clinical pattern. We measured bone density in 84 male and female patients with both dual X-ray absorptiometry (DXA) and single energy quantitative computed tomography (SE-QCT). In the initial and advanced stages of the disease, a high decrease in axial bone density could be verified (DXA: osteopenia in 5% and osteoporosis in 9.2%; SE-QCT: osteopenia in 11.8% and osteoporosis in 30.3%). Peripheral bone density decrease as in osteopenia could be proven in 17.6% by DXA measurement. With SE-QCT, a decrease in vertebral trabecular bone density could already be observed in the initial stage and continued steadily during the course of the disease; cortical bone displayed the same trend up to stages of ankylosis. With DXA, valid conclusions are more likely to be expected in less marked ankylosing stages of AS. In stages of advanced ankyloses in the vertebral region (substantial syndesmophytes), priority should be given to SE-QCT, due to the selective measurement of trabecular and cortical bone. The DXA method often yields values that are too high, and the replacement of vertebral trabecular bone by fatty bone marrow is not usually recorded as standard. There may already be an increased risk of bone fracture in AS in osteopenia on DXA along with an osteoporosis already established on SE-QCT.

Phase- and size-adjusted CT cut-off for differentiating neoplastic lesions from normal colon in contrast-enhanced CT colonography.

A computed tomography (CT) cut-off for differentiating neoplastic lesions (polyps/carcinoma) from normal colon in contrast-enhanced CT colonography (CTC) relating to the contrast phase and lesion size is determined. CT values of 64 colonic lesions (27 polyps <10 mm, 13 polyps > or =10 mm, 24 carcinomas) were determined by region-of-interest (ROI) measurements in 38 patients who underwent contrast-enhanced CTC. In addition, the height (H) of the colonic lesions was measured in CT. CT values were also measured in the aorta (A), superior mesenteric vein (V) and colonic wall. The contrast phase was defined by xA + (1-x)V using x as a weighting factor for describing the different contrast phases ranging from the pure arterial phase (x=1) over the intermediate phases (x=0.9-0.1) to the pure venous phase (x=0). The CT values of the lesions were correlated with their height (H), the different phases (xA+(1-x)V) and the ratio [xA+(I-x)V]/H. The CT cut-off was linearly adjusted to the imaged contrast phase and height of the lesion by the line y=m[xA+(1-x)V]H+y(0). The slope m was determined by linear regression in the correlation (lesion approximately [xA+(i-x)V]/H) and the Y-intercept y(0) by the minimal shift of the line needed to maximize the accuracy of separating the colonic wall from the lesions. The CT value of the lesions correlated best with the intermediate phase: 0.4A + 0.6V (r=0.8 for polyps > or =10 mm, r=0.6 for carcinomas, r=0.4 for polyps <10 mm). The accuracy in the differentiation between lesions and normal colonic wall increased with the height implemented as divisor, reached 91% and was obtained by the dynamic cut-off described by the formula: cut-off (A,V,H)=1.1 [0.4A+0.6V]/H+69.8. The CT value of colonic polyps or carcinomas can be increased extrinsically by scanning in the phase in which 0.4A + 0.6V reaches its maximum. Differentiating lesions from normal colon based on CT values is possible in contrast-enhanced CTC and improves when the cut-off is adjusted (normalized) to the contrast phase and lesion size.

[Indirect MR venography: contrast medium protocols, postprocessing and combination in diagnosing pulmonary emboli with MRI]. / Indirekte MR-Phlebografie: Kontrastmittelprotokolle, Nachverarbeitung und Kombination mit Lungenemboliediagnostik in der MRT.

PURPOSE: Integration of MR venography in a comprehensive MR imaging protocol in patients with suspected pulmonary embolism (PE) and evaluation of contrast media dosage, timing and postprocessing for diagnostic accuracy. MATERIALS AND METHODS: Forty-eight consecutive inpatients with suspected PE or deep vein thrombosis were examined by MR venography according to one of the following protocols: protocol I: MR venography only, 0.25 mmol/kg body weight (BW) Gadopentate dimeglumine (Gd-DTPA) as single dose, bolus timing; protocol II: MR angiography of pulmonary arteries with a cumulative dosage of 0.25 mmol/kg contrast media, modification of coil setting for MR venography without further contrast media application; protocol III: as protocol II but with 0.125 mmol/kg BW, followed by MR venography. Signal-to-noise ratio, contrast-to-noise ratio, number of definable vascular segments and image quality were evaluated. The results were compared to conventional bilateral venography. RESULTS: All MR venography examinations were of diagnostic quality and the examination time was below 10 min. MR venography could be performed in all 48 patients compared to 43 of 48 patients for conventional venography. Significantly more superficial and deep veins of the leg could be visualized by MR venography (94 % compared to 83 % for conventional venography). Sensitivity and specificity were 100 % and 92 %, respectively. Quality differed significantly between 0.125 mmol/kg (protocol III) and 0.25 mmol/kg Gd-DTPA (protocols I and II) while timing did not influence quality (protocol I vs. II). CONCLUSION: An integrated MR diagnostic evaluation of pulmonary arteries and veins of the leg is feasible in patients with suspected PE. MR venography with 0.25 mmol/kg Gd-DTPA reliably depicts the venous system of the leg more completely than conventional venography with at least equivalent diagnostic confidence.

[Biventricular MR volumetric analysis and MR flow quantification in the ascending aorta and pulmonary trunk for quantification of valvular regurgitation]. / Biventrikuläre MR-Volumetrie und MR-Flussmessungen in Aorta ascendens und Truncus pulmonalis zur Quantifizierung von Klappeninsuffizienzen.

PURPOSE: To test the value of biventricular volumetric analysis and the combination of biventricular volumetric analysis with flow quantification in the ascending aorta (Ao) and pulmonary trunk (Pu) for quantification of regurgitation volume and cardiac function in valvular regurgitation (VR) according to location and presence of single or multivalvular disease. MATERIALS AND METHODS: In 106 patients, the stroke volumes were assessed by measuring the biventricular volumes and the forward-stroke volumes in the great and small circulation by measuring the flow in the Ao and Pu. Valve regurgitation volumes and quotients were calculated for single and multivalvular disease and correlated with semiquantitative 2D-echocardiography (grade I-IV). For the assessment of the cardiac function in VR, the volumetric parameters of ejection fraction and end-diastolic (EDV) and end-systolic (ESV) volumes were determined. RESULTS: The detection rate was 49% for left ventricular (LV) VR and 42% for right ventricular (RV) VR. Low LV VR and RV VR usually could not be detected quantitatively, with the detection rate improving with echocardiographically higher insufficiency grades. Quantitative MRI could detect a higher grade solitary aortic valve insufficiency (> or = 2) in 11 of 12 patients and higher grade mitral valve insufficiency in 4 of 10 patients. A significant increase in RV and LV ventricular EDV and ESV was seen more often with increased MR regurgitation volumes. Aortic stenosis did not interfere with flow measurements in the Ao. CONCLUSIONS: Biventricular volumetry combined with flow measurements in Ao and Pu is a robust, applicable and simple method to assess higher grade regurgitation volumes and the cardiac function in single and multivalvular regurgitation at different locations. It is an important application for the diagnosis of VR by MRI.

Noninvasive quantification of brain edema and the space-occupying effect in rat stroke models using magnetic resonance imaging.

BACKGROUND AND PURPOSE: Brain edema is a life-threatening consequence of stroke and leads to an extension of the affected tissue. The space-occupying effect due to brain edema can be quantified in rat stroke models with the use of MRI. The present study was performed to test 2 hypotheses: (1) Can quantification of the space-occupying effect due to brain edema serve as a noninvasive measure for brain water content? (2) Does morphometric assessment of brain swelling allow determination of true infarct size on MRI after correction for the space-occupying effect of edema? METHODS: Thirty rats were subjected to permanent suture middle cerebral artery occlusion. MRI was performed after 6 or 24 hours, and hemispheric swelling was assessed morphometrically. Interobserver and intraobserver agreements were determined for MRI measurements. In study I, the space-occupying effect due to brain edema was correlated with the absolute brain water content by the wet/dry method. In study II, lesion volumes corrected and uncorrected for edema were calculated on MRI and on TTC staining and compared. RESULTS: Interobserver and intraobserver agreements for MRI measurements were excellent (r>or=0.97). Brain water content and hemispheric swelling correlated well after 6 and 24 hours (r>or=0.95). Corrected lesion volumes correlated with r=0.78 between TTC staining and MRI. Without edema correction, lesion volumes were overestimated by 20.3% after 6 hours and by 29.6% after 24 hours of ischemia. CONCLUSIONS: Morphometric assessment of hemispheric swelling on MRI can determine the increase in absolute brain water content noninvasively and can also provide ischemic lesion volumes corrected for brain edema.