The German National Cohort (NAKO) includes an imaging study with standardised whole-body MRI scans, which is being conducted on a subpopulation of approximately 30,000 participants. These scans are performed using identical 3T Skyra scanners (Siemens Healthineers) and provide detailed views of the brain, heart, fat distribution and musculoskeletal system. All imaging data is centrally managed and quality assured by the Imaging Core to ensure consistency and scientific quality.
MRI examination
As part of the German National Cohort (NAKO), MRI is performed as an additional examination involving a subpopulation of approximately 20 percent of all participants. This group consists of randomly selected Level 2 participants from the five MRI study centres and the six referring study centres.
Around 30,000 people took part in this additional examination during the baseline ,examination. The participant group for the first re-examination includes around 18,000 people, and around 12,000 participants are expected to take part in the second re-examination, which is currently ongoing. The additional examinations are taking place at the five NAKO MRI study centres: Augsburg, Berlin, Essen, Mannheim and Neubrandenburg.
- Assignment from a total of eleven NAKO study centres: Augsburg, Berlin North, Berlin Central, Berlin South, Düsseldorf, Essen, Freiburg, Mannheim, Münster, Neubrandenburg and Saarbrücken
- Study-specific 3T MRI systems (MAGNETOM Skyra, Siemens Healthineers, Erlangen, Germany) with identical hardware and software components
- 4 MR Imaging Core Units: University Medical Centre Freiburg (coordination and training), Fraunhofer MEVIS Bremen (image data management), University Medical Centre Heidelberg (incidental findings management), University Medical Centre Greifswald (quality assurance)
- Continuous quality assurance through MR Imaging Core
- Image assessment and review for random results for all participants by certified NAKO radiologists
- The overall procedure and processes remain essentially unchanged across all waves of the study; deviations from the third-party MRI examination are explicitly indicated in the table.
- Focus on four organ areas: brain (NEURO), musculoskeletal system (MSK), thoracoabdominal system (BODY), cardiovascular system (CARDIO)
| Baseline (1U) (2014-2019) | 5-year follow-up (First re-examination, 2U) (2019-2024) | 10-year follow-up (Second re-examination, 3U) (from 2024) | |
| NEURO | T1_3D_SAG (MPRAGE) T2_FLAIR_2D_TRA Resting_State_TRA | T1_3D_SAG (MPRAGE) T2_FLAIR_2D_TRA Resting_State_TRA* DTI_SliceAcc_TRA* SWI_3D_TRA | T1_3D_SAG (MPRAGE) T2_FLAIR_2D_TRA Resting_State_TRA§ DTI_SliceAcc_TRA§ SWI_3D_TRA (CAIPI) |
| MSK | Hip: PD_FS_SPC Spine: T2_TSE (HWS, BWS, LWS, COMP) | Hip: PD_FS_SPC Spine: T2_TSE (HWS, BWS, LWS, COMP) | Hip: PD_FS_SPC (CS) Spine: T2_TSE_DIXON (HWS, BWS, LWS, COMP) |
| BODY | T1_3DVIBE_Dixon_TRA T2_HASTE_TRA ME_3DVIBE (liver) | T1_3DVIBE_Dixon_TRA T2_HASTE_TRA ME_3DVIBE (liver) | T1_3DVIBE_Dixon_TRA T2_HASTE_TRA ME_3DVIBE (liver) Body_DWI (liver) |
| CARDIO | MRA_Tho_COR CINE_SSFP_LAX CINE_SSFP_SAX MOLLI_SAX | MRA_Tho_COR CINE_SSFP_LAX CINE_SSFP_SAX MOLLI_SAX | AdvMRA_Dixon CINE_SSFP_LAX CINE_SSFP_SAX MyoMaps (T1, T2, T2S) |
Focus and MRI sequences during the three waves of examination to date. *As part of the MRI 5-year follow-up (2U), resting state was only performed on the first 500 participants per MRI study centre; DTI was performed on all other participants. §As part of the MRI 10-year follow-up (3U), resting state will be performed on the first 50 per cent and DTI on the second 50 per cent of all participants.
Study procedure, inclusion and exclusion criteria
- Participation in the additional MRI examination is only possible by invitation and after examination in the main study has already been completed.
- The interval between the main study and the MRI examination should be no more than three months, if possible; the interval between individual follow-up examinations should be between 3.5 and 5 years, if possible.
- All persons who have participated in all previous waves of the study, who have no contraindications (see Bamberg et al., 2024 for exclusion criteria) and who are willing to participate in the study are eligible to participate.
- The MRI examination is conducted solely for research purposes and is identical for all participants; no contrast agent is used and it is not intended to clarify symptoms, diagnose specific diseases or monitor the progression of known diseases.
- The MRI examination takes approximately 60-65 minutes without repeat measurements and is performed with the patient lying on their back. Each MRI sequence is repeated a maximum of once, after which a decision is made on site as to which series of measurements will be released for reading.
- The MRI images of all participants will be reviewed by radiology specialists within 10 days for previously defined incidental findings that require clarification.
Image data management
- Web-based applications for image data control: UploadApprovalViewer for medical technical radiology assistants (MTRA) and NAKOViewer for the recording of incidental findings by radiologists.
- Technical and methodological quality monitoring: tests for completeness and uniqueness, programme flow, protocol parameter compliance
- Image-based quality monitoring: weekly phantom measurements and continuous recording of various quality indices such as signal-to-noise ratio, sharpness, ghosting (autoQA)
- The data is transmitted in pseudonymised form in DICOM format to the Imaging Core for image data management (Fraunhofer MEVIS, Bremen).
- All image and metadata are then automatically transferred to the Greifswald Integration Centre, where they are stored in the long-term archives (PACS) of the Central Data Management (Integration Centre, Greifswald/Heidelberg).
Incidental Findings (IF)
- Examination of MRI data sets by personnel trained for NAKO with regard to possible abnormalities
- Communication concept for incidental findings (IFs) according to clinical significance in three categories – acute IFs, IFs requiring communication, IFs not requiring communication (https://nako.de/wp-content/uploads/NAKO-Liste-Zufallsergebnisse-MRT.pdf)
- IF quality assurance:
- Monthly re-evaluation of 10 per cent of MRI image data sets by qualified personnel at the IF Centre (IFQA)
- Upon discovery and confirmation of a previously unreported incidental finding, the initial reader is informed so that they can report it to the participant.
Quality assurance (QA)
- Training and certification of all employees at the NAKO-MRT study centres
- Quarterly quality reports (monthly internally)
- Standard Operating Procedure (SOP): A total of 49 SOPs, including appendices, are available.
- Further quality assurance measures:
- Two on-site and two telephone monitoring sessions per MRI study centre per year Evaluation of the image quality of all collected data sets Re-evaluation of the image quality of 10 per cent of MRI image data sets by (VisQA) Feedback of red ratings (poorly rated image quality) to the MRI study centres Review of all comments from TAs and radiologists
- Monitoring of sub-processes not completed on time (data transfer and documentation, IF reading, preparation of results reports)
- Remote monitoring for all five MRI devices using “teamplay Fleet” (Siemens Healthineers)
Data availability
- Image data from the baseline and MRI first re-examinations
- Sequence and random result data (restricted)
- Defaced neuro MRI data
- Result data
Request MRI data: www.nako.de/transferhub
Information for MRI image data: MRT-Infoblatt (In German only)
Results
Relevant publications on methodology
- Bamberg F, Kauczor HU, Weckbach S, et al. Whole-Body MR Imaging in the German National Cohort: Rationale, Design, and Technical Background. Radiology. 2015;277(1):206-220.doi:10.1148/radiol.2015142272
- Schlett C, Hendel T, Hirsch J, et al. Quantitative, Organ-Specific Interscanner and Intrascanner Variability for 3 T Whole-Body Magnetic Resonance Imaging in a Multicenter, Multivendor Study. Investigative Radiology. 2016;51(4):255-265. http://doi.org/10.1097/RLI.0000000000000237
- Peters A, German National Cohort (NAKO) Consortium, Peters A, et al. Framework and baseline examination of the German National Cohort (NAKO). Eur J Epidemiol. 2022;37(10):1107-1124. http://doi.org/10.1007/s10654-022-00890-5
- Bamberg F, Schlett C, Caspers S, et al. Baseline MRI examination in the NAKO Health Study—findings on feasibility, participation and dropout rates, comfort, and image quality. Deutsches Ärzteblatt international. 2024 http://doi.org/10.3238/arztebl.m2024.0151
Result records
The Imaging Core Units completed data cleaning on 1 July 2025. Since then, the following MRI data sets have been available for scientific use:
- Results of the MRI baseline (including aorta, liver, kidneys, body composition)
- Image data from the baseline and first MRI re-examinations (DICOM)
- Defaced neuro MRI image data from the baseline and MRI 5-year-follow-up (NIFTI)
- Sequence and random result data from the baseline and MRI 5-year-follow-up (restricted)
Current MRI publications
- Ziegelmayer S, Häntze H, Mertens C, et al. Associations of MRI-derived Paraspinal IMAT and LMM with Cardiometabolic Risk Factors: Results from a German Cohort. Radiology. 2026;319(2):e251347. http://doi.org/10.1148/radiol.251347
- Jung M, Reisert M, Rieder H, et al. Body Composition in the General Population: Whole-body MRI–derived Reference Curves from Over 66 000 Individuals. Radiology. 2026;319(2):e251939. http://doi.org/10.1148/radiol.251939
- Niedermayer F, Rospleszcz S, Matthiessen C, et al. Associations of road traffic noise with adipose tissue depots and hepatic fat content – Results from the German National Cohort (NAKO). Environment International. 2025;201:109566 http://doi.org/10.1016/j.envint.2025.109566
- Ziegelmayer S, Häntze H, Mertens C, et al. Intermuscular adipose tissue and lean muscle mass assessed with MRI in people with chronic back pain in Germany: a retrospective observational study. The Lancet Regional Health – Europe. 2025;54:101323. http://doi.org/10.1016/j.lanepe.2025.101323
- Haueise T, Schick F, Stefan N, et al. Refining visceral adipose tissue quantification: Influence of sex, age, and BMI on single slice estimation in 3D MRI of the German National Cohort. Zeitschrift für Medizinische Physik. 2025:S0939388925000352. http://doi.org/10.1016/j.zemedi.2025.02.005
- Jung M, Raghu VK, Reisert M, et al. Deep learning-based body composition analysis from whole-body magnetic resonance imaging to predict all-cause mortality in a large western population. eBioMedicine. 2024;110:105467. http://doi.org/10.1016/j.ebiom.2024.105467
- Kellner E, Sekula P, Lipovsek J, et al. Imaging markers derived from MRI-based automated kidney segmentation. Deutsches Ärzteblatt international. 2024. http://doi.org/10.3238/arztebl.m2024.0040
- Küstner T, Hepp T, Fischer M, et al. Fully Automated and Standardized Segmentation of Adipose Tissue Compartments via Deep Learning in 3D Whole-Body MRI of Epidemiologic Cohort Studies. Radiology: Artificial Intelligence. 2020;2(6):e200010. http://doi.org/10.1148/ryai.2020200010
- Schuppert C, Krüchten RV, Hirsch JG, et al. Whole-Body Magnetic Resonance Imaging in the Large Population-Based German National Cohort Study: Predictive Capability of Automated Image Quality Assessment for Protocol Repetitions. Invest Radiol. 2022;57(7):478-487. http://doi.org/10.1097/RLI.0000000000000861
- Kart T, Fischer M, Winzeck S, et al. Automated imaging-based abdominal organ segmentation and quality control in 20,000 participants of the UK Biobank and German National Cohort Studies. Sci Rep. 2022;12(1):18733. http://doi.org/10.1038/s41598-022-23632-9
- Gatidis S, Kart T, Fischer M, et al. Better Together: Data Harmonization and Cross-Study Analysis of Abdominal MRI Data From UK Biobank and the German National Cohort. Invest Radiol. 2023;58(5):346-354. http://doi.org/10.1097/RLI.0000000000000941
- Haueise T, Schick F, Stefan N, et al. Analysis of volume and topography of adipose tissue in the trunk: Results of MRI of 11,141 participants in the German National Cohort. Sci Adv. 2023;9(19):eadd0433. http://doi.org/10.1126/sciadv.add0433
- Fischer M, Küstner T, Pappa S, et al. Identification of radiomic biomarkers in a set of four skeletal muscle groups on Dixon MRI of the NAKO MR study. BMC Med Imaging. 2023;23(1):104. http://doi.org/10.1186/s12880-023-01056-9
- Schuppert C, Rospleszcz S, Hirsch JG, et al. Automated image quality assessment for selecting among multiple magnetic resonance image acquisitions in the German National Cohort study. Sci Rep. 2023;13(1):22745. http://doi.org/10.1038/s41598-023-49569-1
