1
|
Zhang M, Lei M, Zhang J, Li H, Lin F, Chen Y, Chen J, Xiao M. Feasibility study of three-dimensional printing knee model using the ultra-low-dose CT scan for preoperative planning and simulated surgery. Insights Imaging 2022; 13:151. [PMID: 36153379 PMCID: PMC9509516 DOI: 10.1186/s13244-022-01291-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/24/2022] [Indexed: 11/10/2022] Open
Abstract
Objective To explore the feasibility of the three-dimensional printing (3DP) knee model using the ultra-low-dose computed tomography (CT) scan for preoperative planning and simulated surgery. Methods Thirty-six patients were divided into the standard-dose protocol group (A) and ultra-low-dose protocol group (B). The anteroposterior diameter, left and right diameter of femur, anteroposterior diameter of tibial plateau (APTP), left and right diameter, distance from the intercondylar ridge to tibial tuberosity, lower femur angle, and upper tibial angle were measured on CT images. On the 3D printed knee joint model, Vernier calipers were used to measure: anteroposterior diameter, left and right diameter of the internal and external condyles of femur; left and right diameters, anteroposterior diameters of tibial plateau; upper and lower meridian, left and right diameters of patella. Results With group A as reference, the effective radiation dose in group B was significantly reduced to 97.0% (36.4 ± 3.7 uSv and 1.1 ± 0.2 uSv, respectively). There was no difference in objective parameters for 3DP model (p = 0.31–0.84). None of the quantitative parameters of image quality showed significant difference (p = 0.11–0.96). Despite lower score of image quality and 3DP model in group B (3.0 ± 0.0 vs. 2.1 ± 0.2, 2.9 ± 0.3 vs. 2.2 ± 0.4; p < 0.05), the diagnostic performance was consistent in the two groups (all scores ≥ 2). Image quality and 3DP printed models were highly consistent (k = 0.97). Conclusions Ultra-low-dose protocol reduces the radiation dose while maintaining the image quality of knee. It meets the requirement for 3DP model, internal fixation model selection, and simulated surgery.
Collapse
|
2
|
Mohammadinejad P, Mileto A, Yu L, Leng S, Guimaraes LS, Missert AD, Jensen CT, Gong H, McCollough CH, Fletcher JG. CT Noise-Reduction Methods for Lower-Dose Scanning: Strengths and Weaknesses of Iterative Reconstruction Algorithms and New Techniques. Radiographics 2021; 41:1493-1508. [PMID: 34469209 DOI: 10.1148/rg.2021200196] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Iterative reconstruction (IR) algorithms are the most widely used CT noise-reduction method to improve image quality and have greatly facilitated radiation dose reduction within the radiology community. Various IR methods have different strengths and limitations. Because IR algorithms are typically nonlinear, they can modify spatial resolution and image noise texture in different regions of the CT image; hence traditional image-quality metrics are not appropriate to assess the ability of IR to preserve diagnostic accuracy, especially for low-contrast diagnostic tasks. In this review, the authors highlight emerging IR algorithms and CT noise-reduction techniques and summarize how these techniques can be evaluated to help determine the appropriate radiation dose levels for different diagnostic tasks in CT. In addition to advanced IR techniques, we describe novel CT noise-reduction methods based on convolutional neural networks (CNNs). CNN-based noise-reduction techniques may offer the ability to reduce image noise while maintaining high levels of image detail but may have unique drawbacks. Other novel CT noise-reduction methods are being developed to leverage spatial and/or spectral redundancy in multiphase or multienergy CT. Radiologists and medical physicists should be familiar with these different alternatives to adapt available CT technology for different diagnostic tasks. The scope of this article is (a) to review the clinical applications of IR algorithms as well as their strengths, weaknesses, and methods of assessment and (b) to explore new CT image reconstruction and noise-reduction techniques that promise to facilitate radiation dose reduction. ©RSNA, 2021.
Collapse
Affiliation(s)
- Payam Mohammadinejad
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Achille Mileto
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Lifeng Yu
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Shuai Leng
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Luis S Guimaraes
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Andrew D Missert
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Corey T Jensen
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Hao Gong
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Cynthia H McCollough
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| | - Joel G Fletcher
- From the Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (P.M., L.Y., S.L., A.D.M., H.G., C.H.M., J.G.F.); Department of Radiology, Harborview Medical Center, Seattle, Wash (A.M.); Department of Medical Imaging, Toronto General Hospital, Toronto, ON, Canada (L.S.G.); and Department of Abdominal Imaging, University of Texas MD Anderson Cancer Center, Houston, Tex (C.T.J.)
| |
Collapse
|
3
|
Kupitz D, Wissel H, Wuestemann J, Bluemel S, Pech M, Amthauer H, Kreissl MC, Grosser OS. Optimization of SPECT/CT imaging protocols for quantitative and qualitative 99mTc SPECT. EJNMMI Phys 2021; 8:57. [PMID: 34328565 PMCID: PMC8324619 DOI: 10.1186/s40658-021-00405-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022] Open
Abstract
Background The introduction of hybrid SPECT/CT devices enables quantitative imaging in SPECT, providing a methodological setup for quantitation using SPECT tracers comparable to PET/CT. We evaluated a specific quantitative reconstruction algorithm for SPECT data using a 99mTc-filled NEMA phantom. Quantitative and qualitative image parameters were evaluated for different parametrizations of the acquisition and reconstruction protocol to identify an optimized quantitative protocol. Results The reconstructed activity concentration (ACrec) and the signal-to-noise ratio (SNR) of all examined protocols (n = 16) were significantly affected by the parametrization of the weighting factor k used in scatter correction, the total number of iterations and the sphere volume (all, p < 0.0001). The two examined SPECT acquisition protocols (with 60 or 120 projections) had a minor impact on the ACrec and no significant impact on the SNR. In comparison to the known AC, the use of default scatter correction (k = 0.47) or object-specific scatter correction (k = 0.18) resulted in an underestimation of ACrec in the largest sphere volume (26.5 ml) by − 13.9 kBq/ml (− 16.3%) and − 7.1 kBq/ml (− 8.4%), respectively. An increase in total iterations leads to an increase in estimated AC and a decrease in SNR. The mean difference between ACrec and known AC decreased with an increasing number of total iterations (e.g., for 20 iterations (2 iterations/10 subsets) = − 14.6 kBq/ml (− 17.1%), 240 iterations (24i/10s) = − 8.0 kBq/ml (− 9.4%), p < 0.0001). In parallel, the mean SNR decreased significantly from 2i/10s to 24i/10s by 76% (p < 0.0001). Conclusion Quantitative SPECT imaging is feasible with the used reconstruction algorithm and hybrid SPECT/CT, and its consistent implementation in diagnostics may provide perspectives for quantification in routine clinical practice (e.g., assessment of bone metabolism). When combining quantitative analysis and diagnostic imaging, we recommend using two different reconstruction protocols with task-specific optimized setups (quantitative vs. qualitative reconstruction). Furthermore, individual scatter correction significantly improves both quantitative and qualitative results. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00405-3.
Collapse
Affiliation(s)
- Dennis Kupitz
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.
| | - Heiko Wissel
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany
| | - Jan Wuestemann
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany
| | - Stephanie Bluemel
- Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Maciej Pech
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Holger Amthauer
- Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Michael C Kreissl
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Oliver S Grosser
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| |
Collapse
|
4
|
Grosser OS, Klutzny M, Wissel H, Kupitz D, Finger M, Schenke S, Wuestemann J, Lohmann CH, Hoeschen C, Pech M, Staerke C, Kreissl MC. Quantitative imaging of bone remodeling in patients with a unicompartmental joint unloading knee implant (ATLAS Knee System)-effect of metal artifacts on a SPECT-CT-based quantification. EJNMMI Phys 2021; 8:15. [PMID: 33595735 PMCID: PMC7889783 DOI: 10.1186/s40658-021-00360-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/28/2021] [Indexed: 12/23/2022] Open
Abstract
Background SPECT-CT using radiolabeled phosphonates is considered a standard for assessing bone metabolism (e.g., in patients with osteoarthritis of knee joints). However, SPECT can be influenced by metal artifacts in CT caused by endoprostheses affecting attenuation correction. The current study examined the effects of metal artifacts in CT of a specific endoprosthesis design on quantitative hybrid SPECT-CT imaging. The implant was positioned inside a phantom homogenously filled with activity (955 MBq 99mTc). CT imaging was performed for different X-ray tube currents (I = 10, 40, 125 mA) and table pitches (p = 0.562 and 1.375). X-ray tube voltage (U = 120 kVp) and primary collimation (16 × 0.625 mm) were kept constant for all scans. The CT reconstruction was performed with five different reconstruction kernels (slice thickness, 1.25 mm and 3.75 mm, each 512 × 512 matrix). Effects from metal artifacts were analyzed for different CT scans and reconstruction protocols. ROI analysis of CT and SPECT data was performed for two slice positions/volumes representing the typical locations for target structures relative to the prosthesis (e.g., femur and tibia). A reference region (homogenous activity concentration without influence from metal artifacts) was analyzed for comparison. Results Significant effects caused by CT metal artifacts on attenuation-corrected SPECT were observed for the different slice positions, reconstructed slice thicknesses of CT data, and pitch and CT-reconstruction kernels used (all, p < 0.0001). Based on the optimization, a set of three protocols was identified minimizing the effect of CT metal artifacts on SPECT data. Regarding the reference region, the activity concentration in the anatomically correlated volume was underestimated by 8.9–10.1%. A slight inhomogeneity of the reconstructed activity concentration was detected inside the regions with a median up to 0.81% (p < 0.0001). Using an X-ray tube current of 40 mA showed the best result, balancing quantification and CT exposure. Conclusion The results of this study demonstrate the need for the evaluation of SPECT-CT protocols in prosthesis imaging. Phantom experiments demonstrated the possibility for quantitative SPECT-CT of bone turnover in a specific prosthesis design. Meanwhile, a systematic bias caused by metal implants on quantitative SPECT data has to be considered. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00360-z.
Collapse
Affiliation(s)
- Oliver S Grosser
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany. .,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany.
| | - Marcus Klutzny
- Department of Orthopaedic Surgery, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Magdeburg, Germany
| | - Heiko Wissel
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Dennis Kupitz
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Michael Finger
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Simone Schenke
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Jan Wuestemann
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany
| | - Christoph H Lohmann
- Department of Orthopaedic Surgery, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Magdeburg, Germany
| | - Christoph Hoeschen
- Chair of Medical Systems Technology, Institute of Medical Engineering, Faculty of Electrical Engineering and Information Technology, Otto-von-Guericke University, Magdeburg, Germany
| | - Maciej Pech
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Christian Staerke
- Department of Orthopaedic Surgery, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Magdeburg, Germany
| | - Michael C Kreissl
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg and Medical Faculty of Otto-von-Guericke University, Leipziger Strasse 44, 39120, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| |
Collapse
|