[Unexpected emergencies and emergency findings in outpatient radiology practice]. / Unerwartete Notfälle und Notfallbefunde in der radiologischen Praxis.

CLINICAL/METHODICAL ISSUE: Radiological emergencies or incidental findings that require rapid treatment are part of the daily routine of radiological units in clinics-but also in outpatient radiology. What is special about the care of these patients in the outpatient radiological area? STANDARD RADIOLOGICAL METHODS: An acute or incidental diagnosis of an emergency situation generally occurs with CT or MRI. Outpatient radiology serves as a gatekeeper by preselecting critical cases and then, in close cooperation with all those involved, providing optimal therapy. METHODOLOGICAL INNOVATIONS: Use of CT and MRI to assess the emergency situation allows optimal therapy for the patient to be initiated. In outpatient radiology, close cooperation in the team with the patient and the referring physicians means achieving an optimal result, which can be a great opportunity. ACHIEVEMENTS: Close personal collaboration in the team with the referring physician and the patient is a decisive strength of outpatient radiology and can guarantee optimum care for the patient, especially in the case of acute emergencies or incidental findings which turn out to be clinical-radiological emergencies. The largest challenge in outpatient radiology is to select the critical cases of the many noncritical cases in the face of growing time and cost pressure in a time-economic manner. PRACTICAL RECOMMENDATIONS: Outpatient radiology should be aware of the chance for close cooperation and communication with referring physician and patient, especially in emergency situations-for the well-being of the patient, but also to increase the acceptance and significance of the field of radiology.

Correction to: 18F-NaF PET/CT: EANM procedure guidelines for bone imaging.

The original version of this article unfortunately contained an error. The name and affiliation of "Frédéric Paycha" needs to be corrected. Given in this article is the correct author name and affiliation.

Patients with high-risk differentiated thyroid cancer have a lower I-131 ablation success rate than low-risk ones in spite of a high ablation activity.

OBJECTIVE: To examine success rates in strictly defined high-risk differentiated thyroid cancer (DTC) patients who received a high-activity (≥5550 MBq) adjuvant postoperative I-131 therapy and compare these to the rates found in highest risk and low-risk patients. DESIGN: Retrospective database study. PATIENTS: We examined 377 patients with DTC who received I-131 ablation. Patients with distant metastases were classified as very high risk. Patients with primary tumours >4 cm, extensive extrathyroidal invasion (pT4a or pT4b in accordance with the 7th edition of the TNM system), and patients with ≥5 lymph node metastases or any lateral compartment lymph node metastases were considered high risk. All other patients were considered low risk. MEASUREMENTS: Ablation success rate at first TSH-stimulated follow-up. RESULTS: The ablation success rate was 72·6% in low-risk patients, 51·7% in high-risk patients and 13·8% in highest risk patients (all differences P < 0·001). In none of the groups, a significant difference in the initial I-131 activity was found between patients with successful and unsuccessful ablation (low risk: P = 0·16, high risk: P = 0·91 and highest risk: P = 0·48). Furthermore, there was no difference in ablation success between patients who received <5550 MBq and those who received ≥5550 Mbq (low risk: P = 0·31, high risk: P = 0·69 and highest risk: P = 0·22). CONCLUSIONS: Patients with high-risk DTC have a significantly reduced I-131 ablation success rate compared to low-risk ones in spite of high initial I-131 activities. As successful ablation is prognostically important, efforts should be made to improve outcome in these patients.

Clinical value of 68Ga-DOTATATE-PET/CT compared to stand-alone contrast enhanced CT for the detection of extra-hepatic metastases in patients with neuroendocrine tumours (NET).

PURPOSE: To compare and outline the beneficial skills of combined (68)Ga-DOTATATE positron emission tomography (PET) with concurrent contrast enhanced X-ray computed tomography (ceCT) against stand-alone ceCT in 54 patients with neuroendocrine tumours (NET). METHODS: Patients with histologically confirmed NET and available follow-up of at least 6 months (median 12.6 months; range 6.1-23.2) were included. PET/CT and ceCT images were initially analyzed separately by two blinded nuclear medicine physicians and two radiologists, respectively. In a second step all four physicians reviewed all detected lesions together reaching a consensus-grading for PET/ceCT. The results were then compared to the reference standard consisting of clinical follow-up data. RESULTS: With regard to true positive lesions, PET/ceCT vs. stand alone ceCT detected 139 vs. 48 bone-lesions, 106 vs. 71 lymph node metastases and 26 vs. 26 pulmonary lesions. On a per-patient basis, PET/ceCT achieved a higher sensitivity (100% vs. 47%) and specificity (89% vs. 49%) for bone lesions than ceCT. For lymph nodes the effect was similar (sensitivity 92% vs. 64% and specificity 83% vs. 59%). For the detection of pulmonary lesions the sensitivity was identical (100%) while specificity of PET/ceCT was superior to ceCT-alone (95% vs. 82%). CONCLUSION: In summary, the use of (68)Ga-DOTATATE PET/ceCT leads to an increase in sensitivity and specificity in the detection of extra-hepatic NET metastases compared to stand-alone ceCT. Therefore, (68)Ga-DOTATATE PET/ceCT should be the imaging modality of choice in patients with NET.

(18)F-NaF PET/CT: EANM procedure guidelines for bone imaging.

The aim of this guideline is to provide minimum standards for the performance and interpretation of (18)F-NaF PET/CT scans. Standard acquisition and interpretation of nuclear imaging modalities will help to provide consistent data acquisition and numeric values between different platforms and institutes and to promote the use of PET/CT modality as an established diagnostic modality in routine clinical practice. This will also improve the value of scientific work and its contribution to evidence-based medicine.

Timing of post 131I ablation diagnostic whole body scan in differentiated thyroid cancer patients. Less than four months post ablation may be too early.

AIM: to determine whether the first three months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy (dxWBS) in differentiated thyroid carcinoma patients. PATIENTS, MATERIAL, METHODS: The files of 462 patients who were treated for DTC in our hospital were reviewed. All patients underwent surgical thyroidectomy. 146 patients had data available on a. a dxWBS which was performed less than four months (max 120 days) after 131I ablation with concurrent stimulated TSH stimulated thyroglobulin (Tg) measurement without further therapeutic measures between ablation and dxWBS and b. a second dxWBS or 131I therapy (rxWBS) within 1.5 years after ablation. RESULTS: A discordance between the initial and follow-up scan was found in 25/129 (19%) patients: of 54 patients with a positive initial dxWBS, scan results of a second dxWBS or rxWBS obtained with a suitable distance to the initial scan contradicted the initial one in 15 patients (27%). New lesions were discovered in 10/74 negative first dxWBS cases (14%). A discordance between the initial and follow-up stimulated Tg was found in 5/129 (4%) patients: 2/90 (2%) of patients with a negative stimulated Tg at initial dxWBS subsequently showed a positive results whereas 3/29 (10%) patients with an initially positive Tg showed a negative Tg level at the second procedure. CONCLUSION: Less than four months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy with concurrent TSH stimulated Tg measurement. The identification of the right, later, timepoint however requires further research.

Pretherapeutic dosimetry before 131I therapy of benign thyroid disease. A clinical practice assessment of dosimetric parameters.

AIM: To compare uptake measurements and different methods for the pretherapeutic determination of the effective thyroidal ¹³¹I half life (Teff) to the results of posttherapeutic dosimetric measurements. PATIENTS, METHODS: Retrospective study of 1538 patients who received their first RIT in our department for autonomous thyroid nodules (ATN), autonomous multinodular goiter (AMG) or Graves' disease (GD) between November 1999 and January 2011. Pretherapeutic measurements were performed at any combination of 24 h, 48 h and 6 days after 131I administration. Post-therapy dosimetric measurements were performed in 12 h intervals until discharge. Teff was determined through monoexponential curve fitting. RESULTS: Pretherapeutic Teff values based on measurements at 24 h and 48 h, 24 h and 6 d, 48 h and 6 d as well as on day 24 h, 48 h and 6 d yielded implausible (< 2 d or > 8 d) values for Teff, in 60.4%, 25.7%, 29.1 and 21.4% of available calculations, respectively. The plausible results showed significant, clinically relevant and sometimes considerable overestimations of Teff. Using empirically determined fixed disease specific Teff values resulted in a better congruence between the pre- and posttherapeutic dosimetry results. 24 h measurements were marginally more accurate than 48 h ones in AMG and GD whereas 48 h measurements were marginally more accurate in ATN; these differences are however not clinically relevant. 6 d measurements are clearly less accurate than those after 24 h or 48 h. CONCLUSION: In ATN, AMG and GD, pretherapeutic dosimetry can be performed by a single uptake measurement at 24 h or 48 h using a fixed, disease specific value for Teff. Additional later measurements do not yield a further clinically relevant contribution to accuracy of pretherapeutic dosimetry.

Bone graft scintigraphy. A new diagnostic tool to assess perfusion during surgery.

AIM: To evaluate a scintigraphic tool for intraoperative assessment of vascularized bone graft perfusion before and after transplantation. PATIENTS, METHODS: This pilot study included three patients scheduled for surgical segmental mandibulectomy followed by reconstruction with a vascularized iliac bone graft. A continuous (99m)Tc-pertechnetate infusion was applied selectively arterial into the blood vessel supplying the respective graft before osteotomy as well as after transplantation. Perfusion was analysed by scintigrams acquired using the intraoperative camera systems declipseSPECT and Sentinella. Results were compared qualitatively. RESULTS: Before harvesting the graft, intraoperative scintigraphy revealed a clearly delineated area of the iliac crest with a relatively homogenous pertechnetate distribution representing good perfusion. After osteotomy, transplantation to the mandibula and re-anastomosis of the nutrient vessels, scintigraphy in all patients showed a moderately inhomogenous distribution pattern of the pertechnetate indicating an adequate perfusion of the bone transplant through the arterial anastomosis. CONCLUSION: Intraoperative assessment of bone graft perfusion is possible with the imaging systems Sentinella as well as with declipseSPECT using a continuous intra-arterial infusion of 99mTc-pertechnetate.

RECIST and WHO criteria evaluation of cervical, thoracic and abdominal lymph nodes in patients with malignant lymphoma: manual versus semi-automated measurement on standard MDCT slices.

PURPOSE: Since semi-automated lesion quantification may be more precise than manual uni- and bidimensional measurements, the purpose of this study was to compare semi-automated with manual evaluations of cervical, thoracic and abdominal lymph nodes in patients with malignant lymphoma. MATERIALS AND METHODS: 62 patients with known malignant lymphoma underwent staging with contrast-enhanced 16-MDCT (16x0.7 mm coll., 120 kV, cervical/thoracic/abdominal: 150/120/160 mAseff., 1/1.25 /1 pitch, 4/3 - 5/4 - 5/4 slice thickness/reconstruction increment). On the basis of these standard reconstructed slices, each lesion was quantified in terms of RECIST and its longest orthographic diameter using a semi-automated software tool (Syngo CT Oncology, Siemens Medical Solutions, Forchheim, Germany) and manually by an experienced radiologist. The degree of agreement between manual measurements and software quantification was statistically assessed by computing the concordance correlation coefficient kappa and represented graphically in corresponding Bland-Altman plots. RESULTS: 74/80 cervical, 51/80 thoracic and 75/80 abdominal lymph nodes were correctly evaluated by the software. A strong degree of agreement between both measurement techniques (RECIST diameter: kappa = 0.97 (cervical)/0.98 (thoracic)/0.99 (abdominal); longest orthographic diameter: kappa = 0.97/0.93/0.97) was obtained. CONCLUSION: Semi-automated measurement of cervical, thoracic and abdominal lymph nodes showed valid results on standard axial reconstructions compared to manual quantification with the limitation of a high false segmentation rate in thoracic lymph nodes.

[Evaluation of a novel seldinger-needle for computed tomography guided interventions: initial experiences]. / Evaluierung einer neuen Seldinger-Nadel für computertomografisch gesteuerte Interventionen: Erste Erfahrungen.

PURPOSE: To evaluate a new Seldinger puncture device for computed tomography-guided interventions under difficult conditions, to analyze applicability, and to investigate assets and drawbacks. MATERIALS AND METHODS: From November 2007 to March 2008, we performed CT-guided interventions in 16 patients (7 women, 9 men; mean age 62 years old) using a new 20G-Seldinger needle (Sika-Med, Wiehl, Germany). This novel needle serves as a guide for many different interventional devices due to a guide wire welded on the proximal needle end. It allows continuous application of anesthesia via four tiny holes at the distal needle end until the region of interest is reached. Each intervention was subject to difficult interventional conditions. The indications for intervention were drainage (n = 7), Trucut biopsy of tumor (n = 8) and radiofrequency ablation (n = 1). Handling, success, advantages, drawbacks, complications and patient tolerance were noted after each procedure. A pain scale from 1 - 10 was used to grade the pain level during the intervention. RESULTS: All interventions were performed successfully and no severe complications were observed. Patient tolerance was very good resulting in a mean pain score of 2 +/- 1. Regions with dangerous and difficult access were successfully reached with the new Seldinger needle in 15 of 16 cases by dilatation of the puncture tract and continuous administration of local anesthesia via the system. Furthermore, different devices such as Trucut systems and a drainage catheter were able to be inserted without complication via the needle. With a proximal removable luer-lock connection, liquid material was able to be aspirated in six cases. CONCLUSION: Under difficult interventional conditions, the use of a Seldinger needle as a reliable technique for CT-guided interventions can provide a safe and successful procedure.

[Computer-aided detection of small pulmonary nodules in multidetector spiral computed tomography (MSCT) in children]. / Computerassistierte Detektion (CAD) von kleinen pulmonalen Rundherden in der Mehrdetektor-Spiral-Computertomografie (MDCT) bei Kindern.

PURPOSE: Retrospective evaluation of computer-aided detection software (CAD) for automated detection (LungCAD, Siemens Medical solutions, Forchheim, Germany) and volumetry (LungCARE) of pulmonary nodules in dose-reduced pediatric MDCT. MATERIALS AND METHODS: 30 scans of 24 children (10.4+/-5.9 years, 13 girls, 11 boys, 39.7+/-29.3 kg body weight) were performed on a 16-MDCT for tumor staging (n=18), inflammation (n=9), other indications (n=3). Tube voltage 120 kVp and effective mAs were adapted to body weight. Slice thickness 2 mm, increment 1 mm. A pediatric radiologist (U1), a CAD expert (U2) and an inexperienced radiologist (U3) independently analyzed the lung window images without and with the CAD as a second reader. In a consensus decision U 1 and U 2 were the reference standard. RESULTS: Five examinations had to be excluded from the study due to other underlying lung disease. A total of 24 pulmonary nodules were found in all data sets with a minimal diameter of 0.35 mm to 3.81 mm (mean 1.7+/-0.85 mm). The sensitivities were as follows: U1 95.8% and 100% with CAD; U2 91.7% U3 66.7%. U2 and U3 did not detect further nodules with CAD. The sensitivity of CAD alone was 41.7 % with 0.32 false-positive findings per examination. Interobserver agreement between U1 / U2 regarding nodule detection with CAD was good (k=0.6500) and without CAD very good (k=0.8727). For the rest (U1 /U3; U2 / U3 with and without CAD), it was weak (k=0.0667-0.1884). Depending on the measured value (axial measurement, volume), there is a significant correlation (p=0.0026-0.0432) between nodule size and CAD detection. Undetected pulmonary nodules (mean 1.35 mm; range 0.35-2.61 mm) were smaller than the detected ones (mean 2.19 mm; range 1.35-3.81 mm). No significant correlation was found between CAD findings and patient age (p=0.9263) and body weight (p=0.9271) as well as nodule location (subpleural, intraparenchymal; p=1.0) and noise/SNR. CONCLUSION: In our study with 2 mm slice thickness and very small lesion sizes, the analyzed CAD algorithm for detection and volumetry of pulmonary nodules has limited application in pediatric dose-reduced 16-MDCTs. Determination of lesion size is possible even in the case of false-negatives.

MDCT angiography of the pulmonary arteries: intravascular contrast enhancement does not depend on iodine concentration when injecting equal amounts of iodine at standardized iodine delivery rates.

To compare the impact of iodine concentration using two different contrast materials (CM) at standardized iodine delivery rate (IDR) and overall iodine load in 16-multidetector-row-CT-angiography (MDCTA) of the pulmonary arteries of 192 patients with known or suspected pulmonary embolism. One hundred three patients (group A) received 148 ml of a CM containing 300 mg iodine/ml (Ultravist 300, BayerScheringPharma) at a flow rate of 4.9 ml/s. Eighty-nine patients (group B) received 120 ml of a CM with a concentration of 370 mg iodine/ml (Ultravist 370) at a flow rate of 4.0 ml/s, resulting in a standardized IDR (approximately 1.5 gI/s) and the same overall amount of iodine (44.4 g). Both CM injections were followed by a saline chaser. Mean density values were determined in the pulmonary trunk, the ascending and the descending aorta, respectively. Applying repeated-measures ANOVA, no statistically significant differences between both MDCTA protocols were found (p = 0.5790): the mean density in the pulmonary trunk was 355 +/- 116 Hounsfield Units (group A) and 358 +/- 115 (group B). The corresponding values for the ascending and descending aorta were 295 +/- 79 (group A) and 284 +/- 65 (group B) as well as 272 +/- 71 and 262 +/- 70. In conclusion, the use of standardized IDR and overall iodine load provides comparable intravascular CM density in pulmonary 16-MDCTA for delivering contrast materials with different iodine concentrations.

Contrast enhancement in multidetector-row computed tomography (MDCT) of the abdomen: intraindividual comparison of contrast media containing 300 mg versus 370 mg iodine per ml.

The purpose of this study was to intraindividually evaluate the difference in intraluminal vessel and parenchyma contrast enhancement of two different iodine concentrations in multidetector-row computed tomography (MDCT) of the abdomen. Eighty-three patients underwent baseline and follow-up MDCT-scanning (Somatom Sensation 16; Siemens, Forchheim, Germany) of the abdomen using contrast media containing 370 mg iodine/ml (protocol A; Ultravist 370, Bayer Schering Pharma, Berlin, Germany) and 300 mg iodine/ml (protocol B; Ultravist 300). The total iodine load (37 g iodine) and the iodine delivery rate (1.29 g iodine/s) were identical for both protocols. Contrast enhancement in the portal venous phase was measured in the abdominal aorta, inferior vena cava, portal vein, liver, spleen, pancreas and kidney. Mean attenuation values were compared using paired t-test. Intraindividual comparison revealed no statistically significant differences of the mean attenuation values between protocols A and B for all anatomic sites: abdominal aorta, inferior vena cava, portal vein, liver, spleen, pancreas and kidney (all P > 0.05). Given an injection protocol with constant total iodine load and constant iodine delivery rate, the iodine concentration of contrast media does not significantly influence abdominal contrast enhancement in the portal venous phase.

Indocyanine green fluorescence measurement of intestinal transit and gut perfusion after intestinal manipulation.

BACKGROUND AND AIMS: Postoperative ileus is a common and poorly understood problem of abdominal surgery. The aim of this study was to measure postoperative intestinal transit and to evaluate bowel wall perfusion by a novel in vivo indocyanine green (ICG)-fluorescence measurement following intestinal manipulation (IM). METHODS: Rats underwent a simple intestinal manipulation. Myeloperoxidase-positive cells in the muscularis were stained with the Hanker-Yates reaction and quantified histochemically. Bowel wall perfusion was determined directly and 24 h postoperatively using a laser-fluorescence detection unit. Intestinal transit was visualized 24 h after IM. RESULTS: IM resulted in a massive infiltration (155-fold) of neutrophils into the intestinal muscularis 24 h postoperatively. Bowel wall perfusion significantly decreased directly and 24 h following surgery (29 and 59%, respectively). Gastrointestinal transit was similarly impaired and showed a reduction to 40% of the control values 24 h after IM. CONCLUSION: IM of the rat small intestine caused an impairment in bowel wall perfusion and microcirculation and a significant decrease in gastrointestinal transit. The ICG fluorescence measurement using the described system proved to be a simple and reliable method to evaluate intestinal transit and bowel wall microcirculation in vivo.

Numerical studies of the heterogeneous combustion of char using detailed chemistry.

The oxidation of graphite is used as a model system for the combustion of char. In order to understand this oxidation process a stagnation-point flow of an oxygen stream on a graphite surface is investigated numerically. The chemical reactions in the gas phase as well as on the surface are modelled by a series of elementary steps. The surface reactions take into consideration the different surface complexes formed, the influence of the geometry of the graphite surface and the interaction of gas-phase molecules with surface complexes. The rate coefficients used are estimated by applying methods of the microkinetic analysis of heterogeneous catalytic reactions. The mechanism is used to simulate the combustion rate of a graphite surface and the ratio of CO to CO2 formed on the surface. The simulation results are compared with experimental data and a good agreement is achieved. Furthermore, the fraction of char-bound nitrogen converted to N2 and N2O is calculated.

Pinacidil relaxes porcine and human coronary arteries by activating ATP-dependent potassium channels in smooth muscle cells.

We investigated the effect of the potassium channel opener pinacidil on ATP-dependent K+ channels (KATP) in the relaxation of porcine and human coronary arteries by means of isometric contraction experiments in arterial rings. We also measured whole cell currents in freshly isolated porcine and human coronary artery vascular smooth muscle cells with patch clamp. We first characterized serotonin-induced precontractions in our vessels and proved that the contractions were mediated by Ca2+ influx through voltage-dependent Ca2+ channels. Similarly, we observed that serotonin-induced contractions were strongly enhanced by small K(+)-induced depolarizations. Pinacidil completely relaxed rings preconstricted with 5 microM serotonin and produced dose-dependent relaxations of 5 microM serotonin-preconstricted rings, with an IC50 of 1.26 microM. Similar results were observed (IC50 = 1.15 microM) when the endothelium was removed. The KATP blocker glibenclamide (3 microM), inhibited pinacidil-induced relaxations (5-10 microM) by approximately 25% although the KATP blocker tetrapentylammonium (10 microM), inhibited pinacidil-induced (5-10 microM) relaxations completely. Pinacidil 10 microM had only a minimal effect on rings precontracted with a 50 mM external K+ concentration (IC50 = 60 microM). Porcine and human arterial rings did not differ qualitatively in their responses. Moreover, in the patch clamp experiments pinacidil (1 microM and 20 microM) induced a large, nonrectifying, outward current in both human and porcine cells. The reversal potential was close to the K+ equilibrium potential, suggesting an induction of pinacidil-activated K+ current. The pinacidil-induced (1 microM) current was strongly inhibited by glibenclamide (3 microM). These data show that the relaxation of porcine and human coronary arteries by pinacidil is primarily induced by an opening of KATP in smooth muscle cells. Furthermore, the vasorelaxant effect of pinacidil is not endothelium dependent.

Method of estimating the disposition of drugs in the Danish population by sampling reimbursed prescriptions.

A method by which for a small cost it is possible to obtain a quantitative expression for the utilization, disposition and cost of drugs in a Danish county of 500,000 inhabitants. The procedure makes it possible to follow reimbursed preparations, i. e., drugs considered essential for the treatment of diseases. The sale, in D kr., of reimbursed preparations to individuals comprises about 80% of the sale of preparations requiring prescription. And in turn the sale of the latter amounts to 80% of total drug sales to single subjects. The method is based on systematic utilization of all the information available on each prescription; concepts of 'Entry Parameters', 'Calculated Units' and 'Derived Units' was discussed; the 'units' concern frequency of prescription and age- and sex specific dose-frequencies (weight units or defined daily doses -- DDD's). The possibility of creating a base for calculation of the frequency of certain diseases and of side-effects of drugs is mentioned, and examples of the application of the method to certain categories of patients and to certain drugs are given. From limitations of the method it is concluded that it should be considered as a supplement to other complete methods for the study of drug consumption.