Research computed tomography (CT)
The Institute of Diagnostic and Interventional Radiology is one of the world's leading centers for research in the field of computed tomography. Research in this field focuses in particular on spectral computed tomography (SDCT or spectral CT for short). The working group evaluates and tests technical improvements and new analysis methods from this new method. In addition, it endeavors to translate scientific findings into patient care [LINK: clinical applications of this technology].
Große Hokamp N, Maintz D, Shapira N, et al (2020) Technical background of a novel detector-based approach to dual-energy computed tomography. Diagnostic Interv Radiol 26:68-71. doi: 10.5152/dir.2019.19136
Große Hokamp N, Lennartz S, Maintz D (2018) Basics, implementation and clinical application of dual-energy CT. Radiol up2date 18:303-315. doi: 10.1055/a-0657-7090
Fields of research
Innovative CT imaging: Reduction of radiation and contrast medium dose with improved image quality.
Spectral CT allows a drastic reduction in the radiation dose by significantly improving the image contrast using special image reconstructions. Similarly, the amount of contrast medium applied can also be reduced using spectral CT. In addition to improving image contrast, spectral CT also allows the reduction of image artifacts, which are often found in orthopaedic and dental implants and thus limit the diagnostic value of CT examinations. The comparison with other approaches to dual-energy CT plays a special role in this regard. Research collaborations exist with the Massachusetts General Hospital of Harvard Medical School (Dr. S. Lennartz, Dr. A. Kambadakone), among others.
Große Hokamp N, Gilkeson R, Jordan MK, et al (2019) Virtual monoenergetic images from spectral detector CT as a surrogate for conventional CT images: Unaltered attenuation characteristics with reduced image noise. Eur J Radiol 117:49-55. doi: 10.1016/j.ejrad.2019.05.019
Reimer RP, Flatten D, Lichtenstein T, et al (2019) Virtual monoenergetic images from spectral detector CT enable radiation dose reduction in unenhanced cranial CT. AJNR Am J Neuroradiol 40:1617-1623. doi: 10.3174/ajnr.A6220
Große Hokamp N, Neuhaus V, Abdullayev N, et al (2017) Reduction of artifacts caused by orthopedic hardware in the spine in spectral detector CT examinations using virtual monoenergetic image reconstructions and metal-artifact-reduction algorithms. Skeletal Radiol 47:1-7. doi: 10.1007/s00256-017-2776-5
Laukamp KR, Lennartz S, Neuhaus V-FF, et al (2018) CT metal artifacts in patients with total hip replacements: for artifact reduction monoenergetic reconstructions and post-processing algorithms are both efficient but not similar. Eur Radiol 28:4524-4533. doi: 10.1007/s00330-018-5414-2
Große Hokamp N, Hellerbach A, Gierich A, et al (2018) Reduction of Artifacts Caused by Deep Brain Stimulating Electrodes in Cranial Computed Tomography Imaging by Means of Virtual Monoenergetic Images, Metal Artifact Reduction Algorithms, and Their Combination. Invest Radiol 53:424-431. doi: 10.1097/RLI.0000000000000460
Große Hokamp N, Eck B, Siedek F, et al (2020) Quantification of metal artifacts in computed tomography: methodological considerations. Quant Imaging Med Surg 10:1033-1044. doi: 10.21037/qims.2020.04.03
Zopfs D, Laukamp KR, Pinto dos Santos D, et al (2019) Low-keV virtual monoenergetic imaging reconstructions of excretory phase spectral dual-energy CT in patients with urothelial carcinoma: A feasibility study. Eur J Radiol 116:135-143. doi: 10.1016/j.ejrad.2019.05.003
Iodine maps: Quantitative biomarker from spectral CT
Computed tomography (CT) is one of the most important imaging procedures for imaging tumors in the chest or abdomen; iodine-containing contrast medium is often injected via a vein in the arm to improve image quality. To understand the extent of the tumor burden, length measurements (in cm) are usually performed. A major problem with this procedure is that many tumors swell under therapy - similar to a mosquito bite that is scratched - and this can obscure a response to therapy. Modern CT devices also make it possible to determine tumor perfusion by specifically measuring the iodine concentration after administering iodine-containing contrast agents (so-called iodine maps). This can provide valuable additional information regarding the activity or vitality of a tumor. This information can be obtained for every CT examination without increasing risk or radiation exposure and represents a promising follow-up parameter for tumor imaging.
The accuracy of such iodine maps has so far been researched and demonstrated in phantoms and test measurements. In order to bring this technology into the clinic, it is important to understand whether the results and measurements are also reliable in humans. These investigations are the focus of the working group. In a final project step, the iodine maps will be used specifically for imaging the progression of tumor diseases in order to understand their usefulness for monitoring tumor therapy.
Zopfs D, Reimer RP, Sonnabend K, ..., and Große Hokamp N (2020) Intraindividual Consistency of Iodine Concentration in Dual-Energy Computed Tomography of the Chest and Abdomen. Invest Radiol Publish Ah:181-187. doi: 10.1097/RLI.0000000000000724
Zopfs D, Graffe J, Reimer RP, ..., and Große Hokamp N (2020) Quantitative distribution of iodinated contrast media in body computed tomography: data from a large reference cohort. Eur Radiol. doi: 10.1007/s00330-020-07298-3
Große Hokamp N, Abdullayev N, Persigehl T, ..., and Haneder S (2019) Precision and reliability of liver iodine quantification from spectral detector CT: evidence from phantom and patient data. Eur Radiol 29:2098-2106. doi: 10.1007/s00330-018-5744-0
Lennartz S, Täger P, Zopfs D, Große Hokamp N..., and Persigehl T (2021) Lymph Node Assessment in Prostate Cancer: Evaluation of Iodine Quantification With Spectral Detector CT in Correlation to PSMA PET/CT. Clin Nucl Med 46:303-309. doi: 10.1097/RLU.0000000000003496
Große Hokamp N, Persigehl T (2019) Applications of Dual Energy Computed Tomography in Oncologic Imaging. Cancer Imaging (Proceedings 19th ICIS Meet Teach Course) 19:62. doi: 10.1186/s40644-019-0244-2
Lennartz S, Zopfs D, Abdullayev N, ..., and Persigehl T (2020) Iodine overlays to improve differentiation between peritoneal carcinomatosis and benign peritoneal lesions. Eur Radiol. doi: 10.1007/s00330-020-06729-5
Holz JA, Alkadhi H, Laukamp KR, ..., and Große Hokamp N (2020) Quantitative accuracy of virtual non - contrast images derived from spectral detector computed tomography : an abdominal phantom study. Sci Rep 1-8. doi: 10.1038/s41598-020-78518-5
Lennartz S, Le Blanc M, Zopfs D, ..., and Persigehl T (2019) Dual-Energy CT-derived Iodine Maps: Use in Assessing Pleural Carcinomatosis. Radiology 290:796-804. doi: 10.1148/radiol.2018181567
Body composition as a quantitative imaging parameter in CT
Each CT scan also provides information about the patient's muscle and fat masses, although this is not usually analyzed further in everyday clinical practice. This data can be used "opportunistically" as biomarkers for a wide variety of diseases. One prominent example is the influence of body composition on overall survival in patients with esophageal cancer. The aim here is firstly to develop reliable methods for determining body composition from opportunistically obtained data and secondly to correlate body composition with clinical parameters. In addition to modern image reconstructions from spectral CT, artificial intelligence methods are also used. A particular focus of the working group is research into the influence of body composition on patients with neurological diseases.
Zopfs D, Rinneburger M, Pinto Dos Santos D, ..., and Große Hokamp N (2021) Evaluating anemia using contrast-enhanced spectral detector CT of the chest in a large cohort of 522 patients. Eur Radiol 31:4350-4357. doi: 10.1007/s00330-020-07497-y
Zopfs D, Bousabarah K, Lennartz S, ..., and Große Hokamp N (2020) Evaluating body composition by combining quantitative spectral detector computed tomography and deep learning-based image segmentation. Eur J Radiol 130:109153. doi: 10.1016/j.ejrad.2020.109153
Zopfs D, Theurich S, Große Hokamp N, ..., and Pinto dos Santos D (2019) Single-slice CT measurements allow for accurate assessment of sarcopenia and body composition. Eur Radiol 30:1701-1708. doi: 10.1007/s00330-019-06526-9
Zopfs D, Lennartz S, Zäeske C, ..., and Große Hokamp N (2020) Phantomless assessment of volumetric bone mineral density using virtual non-contrast images from spectral detector computed tomography. Br J Radiol 93:20190992. doi: 10.1259/bjr.20190992
Innovative imaging methods for kidney stones
Imaging of kidney stones plays an important role in the diagnosis, assessment and treatment decision for patients with (suspected) kidney stone disease. The optimal treatment depends on various factors, such as the composition, location and size of the stone. Technical progress over the last few decades has enabled a large number of new applications and at the same time raised numerous scientific questions. In cooperation with the Department of Urology, our research group is working in particular on improving the determination of stone size and composition using new techniques such as dual-layer CT and artificial intelligence.
Reimer RP, Salem J, Merkt M, ..., and Große Hokamp N (2020) Size and volume of kidney stones in computed tomography: Influence of acquisition techniques and image reconstruction parameters. Eur J Radiol 132:109267. doi: 10.1016/j.ejrad.2020.109267
Reimer RP, Klein K, Rinneburger M, ..., and Große Hokamp N (2021) Manual kidney stone size measurements in computed tomography are most accurate using multiplanar image reformatations and bone window settings. Sci Rep 11:1-7. doi: 10.1038/s41598-021-95962-z
Nestler T, Haneder S, Grosse Hokamp N (2019) Modern imaging techniques in urinary stone disease. Curr Opin Urol 29:81-88. doi: 10.1097/MOU.0000000000000572
Grosse Hokamp N, Salem J, Hesse A, ..., and Haneder S (2018) Low-Dose Characterization of Kidney Stones Using Spectral Detector Computed Tomography: An Ex Vivo Study. Invest Radiol 53:457-462. doi: 10.1097/RLI.0000000000000468
Große Hokamp N, Lennartz S, Salem J, ..., and Haneder S (2019) Dose independent characterization of renal stones by means of dual energy computed tomography and machine learning: an ex-vivo study. Eur Radiol. doi: 10.1007/s00330-019-06455-7
Bone marrow imaging with spectral CT and artificial intelligence
While bones can be well assessed with "standard" CT imaging, the assessment of bone marrow is considered a domain of MRI imaging. We address this problem by combining virtual non-calcium reconstructions (from spectral CT) with segmentation techniques using artificial intelligence methods (convolutional neural networks). In this way, we aim to better detect bone metastases and cellular infiltrations in multiple myeloma, but we are also working to improve bone imaging in non-oncologic diseases (e.g. in the assessment of BMD).
Fervers P, Celik E, Bratke G, ..., and Große Hokamp N (2021) Radiotherapy Response Assessment of Multiple Myeloma: A Dual-Energy CT Approach With Virtual Non-Calcium Images. Front Oncol 11:1-10. doi: 10.3389/fonc.2021.734819
Fervers P, Fervers F, Kottlors J, ..., and Große Hokamp N (2021) Feasibility of artificial intelligence-supported assessment of bone marrow infiltration using dual-energy computed tomography in patients with evidence of monoclonal protein - a retrospective observational study. Eur Radiol. doi: 10.1007/s00330-021-08419-2
Abdullayev N, Große Hokamp N, Lennartz S, ..., and Borggrefe J (2019) Improvements of diagnostic Accuracy and visualization of vertebral metastasis using multi-level virtual non-calcium reconstructions from dual-layer spectral detector computed tomography. Eur Radiol 29:5941-5949. doi: 10.1007/s00330-019-06233-5
Koch V, Große Hokamp N, Albrecht MH, ..., and Booz C (2021) Accuracy and precision of volumetric bone mineral density assessment using dual-source dual-energy versus quantitative CT: a phantom study. Eur Radiol Exp 5:1-10. doi: 10.1186/s41747-021-00241-1
Zopfs D, Lennartz S, Zäeske C, ..., and Große Hokamp N (2020) Phantomless assessment of volumetric bone mineral density using virtual non-contrast images from spectral detector computed tomography. Br J Radiol 93:20190992. doi: 10.1259/bjr.20190992
Große Hokamp N, Lennartz S, Salem J, ..., and Haneder S (2019) Dose independent characterization of renal stones by means of dual energy computed tomography and machine learning: an ex-vivo study. Eur Radiol. doi: 10.1007/s00330-019-06455-7
Bone marrow imaging with spectral CT and artificial intelligence
While bones can be well assessed with "standard" CT imaging, bone marrow assessment is considered a domain of MRI imaging. We address this problem by combining virtual non-calcium reconstructions (from spectral CT) with segmentation techniques that utilize artificial intelligence methods (convolutional neural networks). In this way, we aim to better detect bone metastases and cellular infiltrations in multiple myeloma, but we are also working to improve bone imaging in non-oncological diseases (e.g. in the assessment of BMD).
+ Selected publications [COLLAPSIBLE]
Fervers P, Celik E, Bratke G, ..., and Große Hokamp N (2021) Radiotherapy Response Assessment of Multiple Myeloma: A Dual-Energy CT Approach With Virtual Non-Calcium Images. Front Oncol 11:1-10. doi: 10.3389/fonc.2021.734819
Fervers P, Fervers F, Kottlors J, ..., and Große Hokamp N (2021) Feasibility of artificial intelligence-supported assessment of bone marrow infiltration using dual-energy computed tomography in patients with evidence of monoclonal protein - a retrospective observational study. Eur Radiol. doi: 10.1007/s00330-021-08419-2
Abdullayev N, Große Hokamp N, Lennartz S, ..., and Borggrefe J (2019) Improvements of diagnostic Accuracy and visualization of vertebral metastasis using multi-level virtual non-calcium reconstructions from dual-layer spectral detector computed tomography. Eur Radiol 29:5941-5949. doi: 10.1007/s00330-019-06233-5
Koch V, Große Hokamp N, Albrecht MH, ..., and Booz C (2021) Accuracy and precision of volumetric bone mineral density assessment using dual-source dual-energy versus quantitative CT: a phantom study. Eur Radiol Exp 5:1-10. doi: 10.1186/s41747-021-00241-1
Zopfs D, Lennartz S, Zäeske C, ..., and Große Hokamp N (2020) Phantomless assessment of volumetric bone mineral density using virtual non-contrast images from spectral detector computed tomography. Br J Radiol 93:20190992. doi: 10.1259/bjr.20190992