J Dinkel

Publications of J Dinkel

• [Lung cancer staging].

  Authors: C Hintze, J Dinkel, J Biederer, C P Heussel, M Puderbach

  Der Radiologe. 02/2011; 51(2):135-44.

  Lung cancer is the third most frequent new cancer diagnosis in Germany. An elaborate clinical diagnosis is essential for successful therapy planning. The necessary examinations are defined in theLung cancer is the third most frequent new cancer diagnosis in Germany. An elaborate clinical diagnosis is essential for successful therapy planning. The necessary examinations are defined in the current S3 guideline on lung cancer diagnosis and therapy. A compilation of diagnostic reports has led to the current 7th edition of the TNM system. According to this update staging is carried out in terms of tumor extent, lymph node status and distant metastases. The resultant tumor stage forms the basis for individual therapy planning. Current guidelines as well as the current TNM system are presented. The usefulness of modern cross-sectional imaging and the possible modalities in this system is reported.

• [New procedures. Comprehensive staging of lung cancer by MRI].

  Authors: C Hintze, J Dinkel, J Biederer, C P Heussel, M Puderbach

  Der Radiologe. 08/2010; 50(8):699-705.

  Lung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification areLung cancer staging according to the TNM system is based on morphological assessment of the primary cancer, lymph nodes and metastases. All aspects of this important oncological classification are measurable with MRI. Pulmonary nodules can be detected at the clinically relevant size of 4-5 mm in diameter. The extent of mediastinal, hilar and supraclavicular lymph node affection can be assessed at the same time. The predominant metastatic spread to the adrenal glands and spine can be detected in coronal orientation during dedicated MRI of the lungs. Search focused whole body MRI completes the staging. Various additional MR imaging techniques provide further functional and clinically relevant information during a single examination. In the oncological context the most important techniques are imaging of perfusion and tumor motion. Functional MRI of the lungs complements the pure staging and improves surgical approaches and radiotherapy planning.

• Fully automated intrinsic respiratory and cardiac gating for small animal CT.

  Authors: J Kuntz, J Dinkel, S Zwick, T Bäuerle, M Grasruck, F Kiessling, R Gupta, W Semmler, S H Bartling

  Physics in medicine and biology. 04/2010; 55(7):2069-85.

  A fully automated, intrinsic gating algorithm for small animal cone-beam CT is described and evaluated. A parameter representing the organ motion, derived from the raw projection images, is used forA fully automated, intrinsic gating algorithm for small animal cone-beam CT is described and evaluated. A parameter representing the organ motion, derived from the raw projection images, is used for both cardiac and respiratory gating. The proposed algorithm makes it possible to reconstruct motion-corrected still images as well as to generate four-dimensional (4D) datasets representing the cardiac and pulmonary anatomy of free-breathing animals without the use of electrocardiogram (ECG) or respiratory sensors. Variation analysis of projections from several rotations is used to place a region of interest (ROI) on the diaphragm. The ROI is cranially extended to include the heart. The centre of mass (COM) variation within this ROI, the filtered frequency response and the local maxima are used to derive a binary motion-gating parameter for phase-sensitive gated reconstruction. This algorithm was implemented on a flat-panel-based cone-beam CT scanner and evaluated using a moving phantom and animal scans (seven rats and eight mice). Volumes were determined using a semiautomatic segmentation. In all cases robust gating signals could be obtained. The maximum volume error in phantom studies was less than 6%. By utilizing extrinsic gating via externally placed cardiac and respiratory sensors, the functional parameters (e.g. cardiac ejection fraction) and image quality were equivalent to this current gold standard. This algorithm obviates the necessity of both gating hardware and user interaction. The simplicity of the proposed algorithm enables adoption in a wide range of small animal cone-beam CT scanners.

• A Hybrid Breath Hold and Continued Respiration-Triggered Technique for Time-Resolved 3D MRI Perfusion Studies in Lung Cancer.

  Authors: C Hintze, A Stemmer, M Bock, T Kuder, F Risse, J Dinkel, H Prüm, M Puderbach, C Fink, J Biederer, H U Kauczor

  RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin. 10/2009;

  PURPOSE: Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggeringPURPOSE: Assessment of lung cancer perfusion is impaired by respiratory motion. Imaging times for contrast agent wash-out studies often exceed breath hold capabilities, and respiration triggering reduces temporal resolution. Temporally resolved volume acquisition of entire tumors is required to assess heterogeneity. Therefore, we developed and evaluated an MR measurement technique that exceeds a single breath hold, and provides a variable temporal resolution during acquisition while suspending breath-dependent motion. MATERIALS AND METHODS: 20 patients with suspected lung cancer were subjected to perfusion studies using a spoiled 3D gradient echo sequence after bolus injection of 0.07 mmol/kg body weight of Gd-DTPA. 10 acquisitions in expiratory breath hold were followed by 50 navigator-triggered acquisitions under free breathing. Post-processing allowed for co-registration of the 3D data sets. An ROI-based visualization of the signal-time curves was performed. RESULTS: In all cases motion-suspended, time-resolved volume data sets (40 x 33 x 10 cm (3), voxel size: 2.1 x 2.1 x 5.0 mm (3)) were generated with a variable, initially high temporal resolution (2.25 sec) that was synchronized with the breath pattern and covered up to 8? min. In 7 / 20 cases a remaining offset could be reduced by rigid co-registration. The tumors showed fast wash-in, followed by rapid signal decay (8 / 20) or a plateau. CONCLUSION: The feasibility of a perfusion study with hybrid breath hold and navigator-triggered time-resolved 3D MRI which combines high initial temporal resolution during breath hold with a long wash-out period under free breathing was demonstrated.

• [Computed tomography of the lungs. A step into the fourth dimension]

  Authors: J Dinkel, C Hintze, N Rochet, C Thieke, J Biederer

  Der Radiologe. 09/2009; 49(8):698-704.

  PURPOSE: To discuss the techniques for four dimensional computed tomography of the lungs in tumour patients. METHOD: The image acquisition in CT can be done using respiratory gating in two differentPURPOSE: To discuss the techniques for four dimensional computed tomography of the lungs in tumour patients. METHOD: The image acquisition in CT can be done using respiratory gating in two different ways: the helical or cine mode. In the helical mode, the couch moves continuously during image and respiratory signal acquisition. In the cine mode, the couch remains in the same position during at least one complete respiratory cycle and then moves to next position. The 4D images are either acquired prospectively or reconstructed retrospectively with dedicated algorithms in a freely selectable respiratory phase. RESULTS: The time information required for motion depiction in 4D imaging can be obtained with tolerable motion artefacts. Partial projection and stepladder-artifacts are occurring predominantly close to the diaphragm, where the displacement is most prominent. Due to the long exposure times, radiation exposure is significantly higher compared to a simple breathhold helical acquisition. Therefore, the use of 4D-CT is restricted to only specific indications (i.e. radiotherapy planning). CONCLUSION: 4D-CT of the lung allows evaluating the respiration-correlated displacement of lungs and tumours in space for radiotherapy planning.

• [Investigation of respiratory-dependent movements of pulmonary space-occupying lesions with MRI]

  Authors: J Biederer, C Hintze, M Fabel, J Dinkel

  Der Radiologe. 09/2009; 49(8):705-11.

  Parallel imaging and echo sharing techniques have markedly reduced the acquisition times for MRI of large volumes. Dynamic 2 and 3-dimensional data sets of the chest with high temporal resolution (upParallel imaging and echo sharing techniques have markedly reduced the acquisition times for MRI of large volumes. Dynamic 2 and 3-dimensional data sets of the chest with high temporal resolution (up to 10 images/s with single slice and 2 volume/s) allow an analysis of respiratory motion of the lungs and tumors. Time-resolved 2D series in preselected planes can be used to observe respiratory motion during free breathing or after respiratory commands, e.g. to exclude chest wall invasion by a tumor or for diagnosing impairment of respiratory mechanics. Time-resolved 3D-series (4D-MRI) allow monitoring of the spatial displacement of the lungs and tumors as a whole volume. Present limitations such as an overestimation of tumor size and an underestimation of displacement due to a limited temporal resolution are expected to be overcome with further technical developments. However, 4D-MRI already appears to be the appropriate tool to select patients for motion-adapted radiotherapy. In addition 4D-MRI is available for a broad spectrum of scientific applications, as it allows repeated and prolonged series of measurements without radiation exposure.