Florian F Behrendt

University Hospital RWTH Aachen, Aachen, North Rhine-Westphalia, Germany

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Publications (74)205.95 Total impact

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    ABSTRACT: 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. 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. 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. 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.
    Nuklearmedizin 06/2015; 54(4). DOI:10.3413/Nukmed-0733-15-03 · 1.67 Impact Factor
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    ABSTRACT: The prostate-specific membrane antigen (PSMA) has recently emerged as a target for radionuclide imaging and therapy of prostate cancer [1, 2]. However, PSMA expression was also shown on the cell membrane of endothelial cells of tumour neovasculature in a number of other cancers such as renal cell carcinoma [3, 4], colon carcinoma, neuroendocrine tumours, melanoma or breast cancer [3]. However, to our knowledge no study has yet investigated the expression of PSMA in the neovasculature of differentiated thyroid cancer (DTC).[68Ga]PSMA-HBED-CC can be used for positron emission tomography (PET)/CT-based staging of prostate cancer [1] as well as for eligibility screening for and monitoring of PSMA-targeted radionuclide therapy [2].Considering the limited number of therapeutic options currently available for patients with metastasized, 131I-negative, [18F]-2-fluorodeoxyglucose-positive DTC [5], we hypothesized that PSMA expression could be present in DTC as well. This would provide an intere ...
    European Journal of Nuclear Medicine 04/2015; DOI:10.1007/s00259-015-3065-y · 5.22 Impact Factor
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    ABSTRACT: 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.
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    ABSTRACT: The aim of this study is to evaluate the impact of a high resolution (HR) image reconstruction with a voxel size of 2mm in comparison to the most routinely used standard reconstruction with 4mm voxels in patients suffering from prostate cancer having undergone (18)F-methylcholine PET/CT. Phantom studies were performed using a Jaszczak phantom and a custom made phantom containing small hot lesions (size 2-10mm). Clinical evaluation was performed on PET/CT scans of 50 patients. Images were reconstructed with 4mm and 2mm voxel size and analyzed quantitatively using AMIDE and MATLAB. Clinical images were judged by two observers concerning TNM staging, image quality and the correlation of PET and CT data. Phantom studies revealed increased SUVmean and SUVmax values in the HR images (P<0.01). The lower detection limit was approximately 3mm in the HR and 4-5mm in the conventional images. Lower FWHM values were found in the HR images. No significant difference was found concerning the image quality and the correlation of PET and CT (each P>0.5). For both reconstructions, a comparable total amount of lesions was reported (P>0.5) with no impact on the TNM staging. In conclusion, the HR PET reconstruction provides semi-quantitative advantages in the sense of an improved lower detection limit and increased semi-quantitative tumour-to-background ratios. In the setting of choline PET/CT for prostate cancer the high resolution reconstruction could be implemented clinically as there are no relevant qualitative differences between this and the conventional image resolution in terms of image quality, assessment confidence and lesion identification rate.
    Hellenic journal of nuclear medicine 11/2014; DOI:10.1967/s002449910145 · 0.93 Impact Factor
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    ABSTRACT: Purpose To determine the frequency of seemingly pathological retroperitoneal uptake in the location of the coeliac ganglia in patients undergoing [68Ga]PSMA-HBED PET/CT. Methods The study included 85 men with prostate cancer referred for [68Ga]PSMA-HBED PET/CT. The PET/CT scans were evaluated for the local finding in the prostate and the presence of lymph node metastases, distant metastases and coeliac ganglia. The corresponding standardized uptake values (SUV) were determined. SUVmax to background uptake (gluteal muscle SUVmean) ratios were calculated for the ganglia and lymph node metastases. Immunohistochemistry was performed on the ganglia. Results In 76 of the 85 patients (89.4 %) at least one ganglion with tracer uptake was found. For the ganglia, SUVmax and SUVmax to background SUVmean ratios were 2.97 ± 0.88 and 7.98 ± 2.84 (range 1.57-6.38 and 2.83-30.6), respectively, and 82.8 % of all ganglia showed an uptake ratio of >5.0. For lymph node metastases, SUVmax and SUVmax to background SUVmean ratios were 8.5 ± 7.0 and 23.31 ± 22.23 (range 2.06-35.9 and 5.25-115.8), respectively. In 35 patients (41.2 %), no lymph node metastases were found but tracer uptake was seen in the ganglia. Immunohistochemistry confirmed strong PSMA expression in the ganglia. Conclusion Coeliac ganglia show a relevant [68Ga]PSMA-HBED uptake in most patients and may mimic lymph node metastases.
    European journal of nuclear medicine and molecular imaging 09/2014; 42(2). DOI:10.1007/s00259-014-2915-3 · 5.22 Impact Factor
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    ABSTRACT: Background: Ventilation/perfusion single-emission photon CT (V/P-SPECT) is widely used to detect pulmonary embolism (PE). Any pathological deficit on P-SPECT with a corresponding unremarkable V-SPECT is considered an embolism. This means that a deficit on P-SPECT with a corresponding deficit on the ventilation scan correlates with other lung pathologies such as pneumonia, bullous emphysema or tumor. In principle, it is possible to identify any of these lung pathologies on nonenhanced chest CT and so this technique has the potential to replace V-SPECT in the diagnosis of PE. Today, SPECT/CT hybrid imaging systems are increasingly applied in clinical routines. Objectives: We investigated whether embolism can be diagnosed using a combined P-SPECT/CT hybrid imaging approach without V-SPECT. Methods: Ninety-three patients with clinically suspected embolism were investigated with standard V/P-SPECT and a nonenhanced CT scan on a combined SPECT/CT system. A diagnosis of embolism was based on V/P-SPECT (gold standard). P-SPECT/CT datasets were blinded and analyzed without any knowledge of the V-SPECT data. The accuracy of P-SPECT/CT was compared to the gold standard. Results: Embolism was diagnosed in 24/93 patients using V/P-SPECT. In total, 57 lung lobes were affected. P-SPECT/CT significantly (p < 0.01) overdiagnosed embolism in nonaffected patients. In total, 36 cases with 88 affected lung lobes were shown. The sensitivity was 95.8%, the specificity 82.6%, the false-negative rate 4.2% and the false-positive rate 17.3%. Conclusions: Our results demonstrate that a nonenhanced CT scan in a novel hybrid imaging system cannot replace V-SPECT in the scintigraphy-based diagnosis of PE. V-SPECT increases specificity and reduces the number of false-positive results when compared to 'perfusion-only' SPECT/CT. © 2014 S. Karger AG, Basel.
    Respiration 08/2014; 88(4). DOI:10.1159/000365817 · 2.92 Impact Factor
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    ABSTRACT: Context: The determinants of successful I-131 therapy of Graves' disease (GD) are unclear. Objective: To relate dosimetry parameters to outcome of therapy in order to identify significant determinants eu- and/or hypothyroidism after I-131 therapy, in GD patients. Design: Retrospective study. Setting: University hospital. Patients: 206 GD patients treated in our hospital between November of 1999 and January of 2011. All received I-131 therapy aiming at a total absorbed dose to the thyroid of 250 Gy based on pre-therapeutic dosimetry. Main outcome measures: Post-therapy dosimetric thyroid measurements were performed twice daily until discharge; from these measurements thyroid I-131 half-life, the total thyroid absorbed dose and the maximum dose rate after I-131 administration were calculated. Results: 48.5% of patients were hypothyroid and 28.6% of patients were euthyroid after I-131 therapy. In univariate analysis non-hyperthyroid and hyperthyroid patients only differed by gender. A lower thyroid mass, a higher activity per gram thyroid tissue, a shorter effective thyroidal I-131 half life and a higher maximum dose rate, but not the total thyroid absorbed dose, were significantly associated with hypothyroidism. In multivariate analysis, the maximum dose rate remained the only significant determinant of hypothyroidism (p<0.001). Maximum dose rates of 2.2 Gy/h and higher were associated with a 100% hypothyroidism rate. Conclusion: Not the total thyroid absorbed dose, but the maximum dose rate is a determinant of successfully achieving hypothyroidism in Graves' disease. Dosimetric concepts aiming at a specific total thyroid absorbed dose will therefore require reconsideration if our data are confirmed prospectively.
    Journal of Clinical Endocrinology &amp Metabolism 07/2014; DOI:10.1210/jc.2014-1347 · 6.31 Impact Factor
  • RöFo - Fortschritte auf dem Gebiet der R 04/2014; 186(S 01). DOI:10.1055/s-0034-1373141 · 1.96 Impact Factor
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    ABSTRACT: To compare the cost-effectiveness of (99m)Tc-methoxyisobutylisonitrile (MIBI) thyroid scintigraphy and the Afirma® gene expression classifier for the assessment of cytologically indeterminate thyroid nodules. A decision tree model was used. Costs were calculated from the perspective of the German health insurance system. The robustness of the results was assessed with probabilistic sensitivity analyses using a Monte Carlo simulation. Life expectancy was 34.3 years (estimated costs per patient 1,459 - 2,224) for the MIBI scan and 34.1 years (estimated costs 3,560 - 4,071) for the molecular test. These results were confirmed by the Monte Carlo simulation. MIBI thyroid scintigraphy is more cost-effective than the gene expression classifier.
    European Journal of Nuclear Medicine 04/2014; 41(8). DOI:10.1007/s00259-014-2760-4 · 5.22 Impact Factor
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    ABSTRACT: Imaging with positron emission tomography (PET) and (68)Ga-DOTA peptides is a promising method in intracranial meningiomas. Especially in recurrent meningioma discrimination between scar tissue and recurrent tumor tissue in magnetic resonance imaging (MRI) is often difficult. We report the first case of (68)Ga-DOTATATE-PET/computed tomography (PET/CT) imaging in recurrent spinal meningioma. A 64-year-old Caucasian female patient was referred to our department with the second recurrence of thoracic meningothelial meningioma. In MRI, it remained unclear if the multiple enhancements seen represented scar tissue or vital tumor. We offered (68)Ga-DOTATATE-PET/CT imaging in order to evaluate the best strategy. (68)Ga-DOTATATE-PET/CT imaging revealed strong tracer uptake in parts of the lesions. The pattern did distinctly differ from MRI enhancement. Multiple biopsies were performed in the PET-positive and PET-negative regions. Histological results confirmed the prediction of (68)Ga-DOTATATE-PET with vital tumor in PET-positive regions and scar tissue in PET-negative regions. Differentiating scar tissue from tumor can be challenging in recurrent spinal meningioma with MRI alone. In the presented case, (68)Ga-DOTATATE-PET imaging was able to differentiate noninvasively between tumor and scar.
    Journal of craniovertebral junction and spine 01/2014; 5(1):44-6. DOI:10.4103/0974-8237.135224
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    ABSTRACT: The aim of this study was to assess whether F-FDG PET combined with x-ray CT (F-FDG PET/CT) findings have a prognostic impact in patients with carcinoma of unknown primary (CUP). Seventy patients with CUP who were referred for F-FDG PET/CT were included. F-FDG PET/CT results were checked against available histologic diagnosis and follow-up data. For each patient, the SUVmax of the lesion with maximum uptake was measured. In 26% of the patients, a primary tumor was identified. The follow-up period after F-FDG PET/CT scan ranged between 3 and 45 months. Kaplan-Meier analysis revealed 1-year survival rates of 92% in the group without evidence of malignancy on F-FDG PET/CT, 78% in the group with locoregional disease, and 34% in the group with extensive disease on F-FDG PET/CT. Three-year survival rates in these groups were 73%, 71%, and 23%, respectively (P = 0.001). There was no significant survival difference between patients with regionally confined disease without identification of the primary tumor and those in whom the primary tumor was identified on F-FDG PET/CT (P = 0.25). This was also the case for patients with extensive disease (P = 0.26). The SUVmax of the lesion with maximum uptake was not significantly related to survival (P = 0.56). F-FDG PET/CT is a helpful tool for the identification of the primary tumor in patients with CUP; it is also able to provide an accurate assessment of prognosis based on the extent of the disease without the need for identification of the primary tumor.
    Clinical nuclear medicine 12/2013; DOI:10.1097/RLU.0000000000000304 · 2.86 Impact Factor
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    ABSTRACT: The aim of the present study was to investigate the diagnostic and prognostic value of combined (18)F-2-fluorodeoxyglucose positron emission tomography and contrast enhanced X-ray computed tomography (FDG-PET/CT) in women with a suspicion of recurrent ovarian cancer. We retrospectively reviewed 48 patients with a suspicion of recurrent ovarian cancer who were referred to our department for combined FDG-PET/CT. Median follow-up was 25 months. 38/48 (79%) patients showed pathological findings on PET/CT. 17/48 (35%) of patients died of ovarian cancer. One FDG-PET/CT was false positive and one was false negative, leading to a sensitivity and positive predictive value of 97% and a specificity and negative predictive value of 90%. 33/48 (69%) underwent a change in therapy following FDG-PET/CT. There was a significantly better survival in FDG-PET/CT negative than in positive patients (p=0.04). In the FDG-PET/CT negative group no patients had died of ovarian cancer during follow-up. Remarkably, there was no difference in survival between patients who only had peritoneal metastases on FDG-PET/CT and those who also had extraperitoneal metastases (p=0.71). A negative FDG-PET/CT has a high negative predictive value for the presence of disease and, more importantly, is associated with a very good disease-specific survival rate.
    European journal of radiology 12/2013; 83(3). DOI:10.1016/j.ejrad.2013.12.006 · 2.16 Impact Factor
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    ABSTRACT: In patients with differentiated thyroid carcinoma (DTC), metastases can either show iodine-131 (I) uptake on whole-body scintigraphy or F-2-fluoro-2-deoxy-D-glucose (F-FDG) uptake on combined PET and X-ray computed tomography (PET/CT), or a mix of both. The present study investigates the relationship between uptake patterns and prognosis in DTC patients, using thyroglobulin doubling time (TgDT) as a surrogate marker of prognosis. We retrospectively examined F-FDG PET/CT and I WBS in 65 DTC patients who were referred to our department of nuclear medicine for F-FDG PET/CT between May 2007 and June 2011. Eight patients were excluded from analysis because of other diseases that caused intense F-FDG uptake or because of failure to show I WBS uptake. F-FDG uptake was seen in 30 out of 57 (53%) patients, of whom 14 showed some degree of I uptake. In these 30 positive scans, we identified a total of 181 F-FDG-positive lesions. Of these, 60 lesions (33%) showed concurrent I uptake on whole-body scintigraphy. Of the nine patients with a positive TgDT in the patient group eight had F-FDG-positive, I-negative lesions, indicating poorer prognosis for this group. In this initial exploratory retrospective study there appears to be an association between a positive TgDT and F-FDG-positive, I-negative metastases, which should encourage further studies in order to establish whether F-FDG PET-CT is the preferred primary imaging modality in patients with a positive TgDT. Roughly two-thirds of patients with a negative TgDT will show at least some degree of I positivity, potentially enabling further I therapy.
    Nuclear Medicine Communications 11/2013; 35(2). DOI:10.1097/MNM.0000000000000025 · 1.37 Impact Factor
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    ABSTRACT: Molecular imaging of apoptosis is frequently discussed for monitoring cancer therapies. Here, we compare the low molecular weight phosphatidylserine-targeting ligand zinc(2+)-dipicolylamine (Zn(2+)-DPA) with the established but reasonably larger protein annexin V. Molecular apoptosis imaging with the fluorescently labelled probes annexin V (750 nm, 36 kDa) and Zn(2+)-DPA (794 nm, 1.84 kDa) was performed in tumour-bearing mice (A431). Three animal groups were investigated: untreated controls and treated tumours after 1 or 4 days of anti-angiogenic therapy (SU11248). Additionally, μPET with (18) F-FDG was performed. Imaging data were displayed as tumour-to-muscle ratio (TMR) and validated by quantitative immunohistochemistry. Compared with untreated control tumours, TUNEL staining indicated significant apoptosis after 1 day (P < 0.05) and 4 days (P < 0.01) of treatment. Concordantly, Zn(2+)-DPA uptake increased significantly after 1 day (P < 0.05) and 4 days (P < 0.01). Surprisingly, annexin V failed to detect significant differences between control and treated animals. Contrary to the increasing uptake of Zn(2+)-DPA, (18) F-FDG tumour uptake decreased significantly at days 1 (P < 0.05) and 4 (P < 0.01). Increase in apoptosis during anti-angiogenic therapy was detected significantly better with the low molecular weight probe Zn(2+)-DPA than with the annexin V-based probe. Additionally, significant treatment effects were detectable as early using Zn(2+)-DPA as with measurements of the glucose metabolism using (18) F-FDG. • The detection of apoptosis by non-invasive imaging is important in oncology. • A new low molecular weight probe Zn (2+)-DPA shows promise in depicting anti-angiogenic effects. • The small Zn (2+)-DPA ligand appears well suited for monitoring therapy. • Treatment effects are detectable just as early with Zn (2+)-DPA as with (18) F-FDG.
    European Radiology 10/2013; DOI:10.1007/s00330-013-3014-8 · 4.34 Impact Factor
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    European Journal of Nuclear Medicine 10/2013; 41(1). DOI:10.1007/s00259-013-2583-8 · 5.22 Impact Factor
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    ABSTRACT: To investigate the quantitative and qualitative differences between combined positron emission tomography and computed X-ray tomography (PET/CT) enhanced with contrast medium with either an iodine concentration 300mg/ml or 370mg/ml. 120 consecutive patients scheduled for F-18-Fluorodeoxyglucose (FDG) PET/CT were included. The first (second) 60 patients received contrast medium with 300 (370) mg iodine/ml. Intravenous injection protocols were adapted for an identical iodine delivery rate (1.3mg/s) and body surface area (BSA) adapted iodine dose (22.26gI/m(2)). Maximum and mean standardized uptake values (SUVmax; SUVmean) and contrast enhancement (HU) were determined in the ascending aorta, the abdominal aorta, the inferior vena cava, the portal vein, the liver and the right kidney in the venous contrast medium phase. PET data were evaluated visually for the presence of malignancy and image quality. Both media caused significantly higher values for HU, SUVmean and SUVmax for the enhanced PET/CT than the non-enhanced one (all p<0.01). There were no significant differences in the degree of increase of HU, SUVmean and SUVmax between the two contrast media at any anatomic site (all p>0.05). Visual evaluation of lesions showed no differences between contrast and non-contrast PET/CT or between the two different contrast media (p=0.77). When using a constant iodine delivery rate and total iodine dose in a BSA adapted injection protocol, there are no quantitative or qualitative differences in either CT or PET between contrast media with an iodine concentration of 300mg/ml and 370mg/ml, respectively.
    European journal of radiology 09/2013; 82(12). DOI:10.1016/j.ejrad.2013.09.013 · 2.16 Impact Factor
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    ABSTRACT: To compare the effects of two different contrast medium concentrations for use in computed X-ray tomography (CT) employing two different injection protocols on positron emission tomography (PET) reconstruction in combined 2-(18)F-desoxyglucose (FDG) PET/CT in patients with a suspicion of lung cancer. 120 patients with a suspicion of lung cancer were enrolled prospectively. PET images were reconstructed with the non-enhanced and venous phase contrast CT obtained after injection of iopromide 300mg/ml or 370mg/ml using either a fixed-dose or a body surface area adapted injection protocol. Maximum and mean standardized uptake values (SUVmax and SUVmean) and contrast enhancement (HU) were determined in the subclavian vein, ascending aorta, abdominal aorta, inferior vena cava, portal vein, liver and kidney and in the suspicious lung lesion. PET data were evaluated visually for the presence of malignancy and image quality. At none of the sites a significant difference in the extent of the contrast enhancement between the four different protocols was found. However, the variability of the contrast enhancement at several anatomical sites was significantly greater in the fixed dose groups than in the BSA groups for both contrast medium concentrations. At none of the sites a significant difference was found in the extent of the SUVmax and SUVmean increase as a result of the use of the venous phase contrast enhanced CT for attenuation. Visual clinical evaluation of lesions showed no differences between contrast and non-contrast PET/CT (P=0.32). Contrast enhanced CT for attenuation correction in combined PET/CT in lung cancer affects neither the clinical assessment nor image quality of the PET-images. A body surface adapted contrast medium protocol reduces the interpatient variability in contrast enhancement.
    European journal of radiology 07/2013; 82(10). DOI:10.1016/j.ejrad.2013.06.020 · 2.16 Impact Factor
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    ABSTRACT: Both iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high-iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identical. This study evaluates the effect of using different iodine concentrations on intravascular attenuation in a circulation phantom while maintaining a constant IDR. A circulation phantom with a low-pressure venous compartment and a high-pressure arterial compartment simulating physiological circulation parameters was used (heart rate, 60 beats per minute; stroke volume, 60 mL; blood pressure, 120/80 mm Hg). Maintaining a constant IDR (2.0 g/s) and a constant total iodine load (20 g), prewarmed (37°C) contrast media with differing iodine concentrations (240-400 mg/mL) were injected into the phantom using a double-headed power injector. Serial computed tomographic scans at the level of the ascending aorta (AA), the descending aorta (DA), and the left main coronary artery (LM) were obtained. Total amount of contrast volume (milliliters), iodine delivery (grams of iodine), peak flow rate (milliliter per second), and intravascular pressure (pounds per square inch) were monitored using a dedicated data acquisition program. Attenuation values in the AA, the DA, and the LM were constantly measured (Hounsfield unit [HU]). In addition, time-enhancement curves, aortic peak enhancement, and time to peak were determined. All contrast injection protocols resulted in similar attenuation values: the AA (516 [11] to 531 [37] HU), the DA (514 [17] to 531 [32] HU), and the LM (490 [10] to 507 [17] HU). No significant differences were found between the AA, the DA, and the LM for either peak enhancement (all P > 0.05) or mean time to peak (AA, 19.4 [0.58] to 20.1 [1.05] seconds; DA, 21.1 [1.0] to 21.4 [1.15] seconds; LM, 19.8 [0.58] to 20.1 [1.05] seconds). This phantom study demonstrates that constant injection parameters (IDR, overall iodine load) lead to robust enhancement patterns, regardless of the contrast material used. Higher iodine concentration itself does not lead to higher attenuation levels. These results may stimulate a shift in paradigm toward clinical usage of contrast media with lower iodine concentrations (eg, 240 mg iodine/mL) in individual tailored contrast protocols. The use of low-iodine concentration contrast media is desirable because of the lower viscosity and the resulting lower injection pressure.
    Investigative radiology 07/2013; DOI:10.1097/RLI.0b013e31829979e8 · 4.45 Impact Factor
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    ABSTRACT: Objectives To investigate simultaneous dual-isotope SPECT/CT with two differently radioisotope-labelled albumin-microsphere fractions for treatment planning of hepatic radioembolisation. Methods In addition to 99mTechnetium-labelled albumin microspheres (commercially available), we performed labelling with 111Indium. Binding stability of 111Indium-labelled microspheres was tested in vitro and in vivo in mice. Simultaneous dual-isotope SPECT/CT imaging was validated in an anthropomorphic torso phantom; subsequently, dual-isotope SPECT/CT was performed under in-vivo conditions in pigs (n = 3) that underwent transarterial injection of 99mTechnetium- and 111Indium-labelled microspheres in the liver (right and left hepatic artery, respectively), in both kidneys and in the gluteal musculature. In total, n = 18 transarterial injections were performed. Results In-vitro testing and in-vivo studies in mice documented high binding stability for both 99mTechnetium-labelled and 111Indium-labelled microsphere fractions. In phantom studies, simultaneous dual-isotope SPECT/CT enabled reliable separation of both isotopes. In pigs, the identified deposition of both isotopes could be accurately matched with intended injection targets (100 %, 18/18 intended injection sites). Furthermore, an incidental deposition of 99mTechnetium-labelled microspheres in the stomach could be correlated to the test injection into a right hepatic artery. Conclusion Simultaneous dual-isotope SPECT/CT after transarterial injection with 99mTechnetium- and 111Indium-labelled microspheres is feasible. Thus, it may offer additional, valuable information compared to single 99mTechnetium-labelled albumin examinations. Key Points • Simultaneous dual-isotope SPECT/CT with 111 In- and 99m Tc-labelled albumin microspheres is feasible. • Differentiation of two microsphere fractions after transarterial injection is possible. • The origin of an extra-hepatic microsphere deposition can be correlated to the corresponding artery. • This technique could reduce the setup time for selective internal radiation treatment.
    European Radiology 06/2013; 23(11). DOI:10.1007/s00330-013-2916-9 · 4.34 Impact Factor
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    ABSTRACT: OBJECTIVE. The objective of our study was to identify the iodine concentration that yields the highest intravascular contrast enhancement in MDCT angiography by intraindividual comparison in an animal model. MATERIALS AND METHODS. Six pigs underwent repeated chest MDCT examinations under standardized conditions using the same contrast medium (iopromide) with different iodine concentrations (150, 240, 300, and 370 mg I/mL). The contrast injection protocol was adapted to ensure an identical iodine delivery rate of 1.5 g I/s and the same total iodine dose of 300 mg/kg of body weight for all studies. Dynamic CT scans were acquired at the levels of the pulmonary artery and the ascending and descending aorta. Pulmonary and aortic peak enhancement values as well as time to peak (TTP) were calculated from time-enhancement curves. RESULTS. Pulmonary and aortic peak contrast enhancement values were significantly higher with the 240 and 300 mg I/mL contrast media than the 150 and 370 mg I/mL contrast media (e.g., ascending aorta: 240 vs 150, p = 0.0070; 300 vs 150, p = 0.0096; 240 vs 370, p = 0.0262; 300 vs 370, p = 0.0079). TTP values tended to be lower for the 150 mg I/mL contrast medium than for the contrast media with higher iodine concentrations. CONCLUSION. Comparison of contrast media with iodine concentrations ranging from 150 to 370 mg I/mL showed that contrast enhancement was significantly improved with the use of 240 and 300 mg I/mL contrast media given a fixed identical iodine delivery and normalized total iodine load in a porcine model. Contrast media with a moderate iodine concentration are most suitable for obtaining the highest intravascular contrast enhancement in CT angiography.
    American Journal of Roentgenology 05/2013; 200(5):1151-6. DOI:10.2214/AJR.12.8984 · 2.74 Impact Factor

Publication Stats

418 Citations
205.95 Total Impact Points

Institutions

  • 2008–2014
    • University Hospital RWTH Aachen
      • Department of Neurology
      Aachen, North Rhine-Westphalia, Germany
  • 2013
    • Maastricht University
      • Faculty of Health, Medicine and Life Sciences
      Maestricht, Limburg, Netherlands
  • 2006–2013
    • RWTH Aachen University
      • • Department of Nuclear Medicine
      • • Department of Diagnostic and Interventional Radiology
      Aachen, North Rhine-Westphalia, Germany