Bone Single Photon Emission Computed Tomography Research Articles

Stability of standardized uptake values for quantitative bone SPECT for jawbone lesions: a single-center cross-sectional study

BackgroundThe long time required for bone uptake of radiopharmaceutical material after injection for bone scintigraphy is a burden for patients with poor health. Thus, to assess whether the uptake time could be reduced for single-photon emission computed tomography (SPECT) of the jawbone, this study evaluated differences in maximum standardized uptake values (SUVmax) within patients using SPECT imaging at 2 and 3 hours after radiopharmaceutical injection.MethodsA total of 33 patients undergoing treatment or in post-treatment follow-up for medication-related osteonecrosis of the jaw, who visited our hospital between July 2020 and August 2021 and could receive SPECT twice on the same day, were enrolled in the study. Patients were injected with technetium-99 m hydroxymethylene diphosphonate (Tc-99 m HMDP) intravenously. The SUVmax for healthy parietal bones and jawbone lesions were calculated from the SPECT images using quantitative analysis software, and the SUVmax were compared between 2- and 3-hour uptake times.ResultsAfter exclusion, 30 patients were included in the study. In the 2-hour and 3-hour images, the median SUVmax of the parietal bones were 1.90 and 1.81, respectively, and those of the jawbone lesions were 9.25 and 9.39, respectively. The limits of agreement (LOA) ranged from − 0.33 to 0.25 in the parietal bones, and the %LOA ranged from − 9.8 to 17.3% in the jawbone lesions, showing high equivalence between the two uptake durations. The SUVmax showed no clinical differences between the 2- and 3-hour uptake durations for Tc-99 m HMDP SPECT of the jawbone.ConclusionsThe results of this study justify a 2–3-hour uptake window when performing quantitative SPECT of the jawbone. Therefore, the minimum uptake time can potentially be reduced to only 2 hours.

The clinical effectiveness of fused image of single-photon emission CT and facial CT for the evaluation of degenerative change of mandibular condylar head

BackgroundThe primary objective of this study was to assess the clinical effectiveness of fused images obtained from single-photon emission computed tomography (SPECT) and facial computed tomography (CT) for evaluating degenerative changes in the mandibular condylar head. This assessment was accomplished by comparing the Technetium-99 m methylene diphosphonate (99mTc-MDP) uptake ratio with the results of clinical and radiographic findings.MethodsThe study included 17 patients (3 males and 14 females) with suspected osteoarthritis of the mandibular condyle, totaling 34 temporomandibular joints (TMJs). Based on clinical and radiographic examinations, the TMJs were categorized into four groups: normal (group N), internal derangement (group ID), osteoarthritis (group OA), and osteoarthritis sequelae (group OAseq). For each patient, bone SPECT and facial CT scans were registered and reconstructed to create fused SPECT/CT images. The 99mTc-MDP uptake levels in the TMJs were statistically compared among the four groups.ResultsThe 99mTc-MDP uptake ratio showed a gradual increase in the order of the following: group N, group OAseq, group ID, and group OA. There was a significant difference observed among groups (p = 0.003), mainly driven by the disparity between group OA and both group N (p < 0.001) and group OAseq (p = 0.048).ConclusionFused SPECT/CT image can be an effective tool for evaluating degenerative changes in the mandibular condylar head. The technique demonstrated the ability to differentiate between normal TMJs and those with internal derangement, osteoarthritis, or osteoarthritis sequelae. This approach holds promise as a valuable method in clinical assessments of TMJ degeneration.

Effects of CT-based attenuation correction on quantitative SPECT/CT of jawbone.

With single photon emission computed tomography (SPECT)/computed tomography (CT) quantitative examinations, CT-based attenuation correction (CTAC) is considered necessary, though its effect on the quantitative values of an examined area close to the body surface, such as the jawbone, has not been elucidated. We performed an investigation to determine whether quantitative evaluation using a bone SPECT standalone device without CT is possible. The calculated indices were maximum standardized uptake value (SUVmax) and SUVpeak. Grouping was performed based on the presence or absence of CTAC. The CTAC group underwent CTAC, while the noAC group did not.Validation was performed using clinical data of patients who underwent a jawbone SPECT/CT examination. Becquerel calibration factor (BCF) is required for calculation of SUV, and was determined with values obtained with both phantom and syringe methods. The index for the uptake areas in each group was assessed using a paired t-test. Using BCF obtained with the phantom method, both SUVmax and SUVpeak were higher in the noAC group. In contrast, BCF obtained with the syringe method showed no significant difference between the CTAC and noAC groups in regard to SUVmax and SUVpeak. This tendency was found regardless of the device used. Also, a high correlation was observed between the groups for both devices (r=0.95 and 0.93). Our findings show that BCF obtained with a syringe method should be used when performing quantitative evaluation without CTAC. They also indicate that quantitative evaluation using a SPECT standalone device may be possible for jawbone SPECT/CT examinations.

Hybrid single-photon emission computed tomography bone imaging for the evaluation of non-specific lower back pain

BackgroundThis is a single-center retrospective study designed to assess the correlation between the location of “hots spots” on single-photon emission computed tomography (SPECT) and the severity of joint degeneration on computed tomography (CT), in addition to understanding whether these hot spots correlate with the pain generating sites causing the non-specific lower back pain. MethodsAll patients who had undergone hybrid SPECT-CT imaging of the lower back over a one-year period at our institution were identified. Twenty joints were assessed from each patient. Joints for assessment were chosen from the intervertebral discs, facet (zygapophysial) and sacroiliac joints. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curves and quantified using the area under the receiver operating characteristic curve (AUROC). ResultsOver a one-year period, 111 patients were identified, with the primary indication being non-specific lower back pain in 73 (66%). Hot spots were observed on SPECT in 79% of patients, with 86% having some degree of degeneration in at least one joint on CT. Degeneration was found to be significantly associated with the presence of hot spots for the majority of joints, with the strongest association seen in the L3/L4 intervertebral joint, for which the rates of hot spots were 1% for grade 0, 26% for grade 1 and 78% for grades 2–3 (AUROC: 0.91, p<0.001). Neither the presence of hot spots nor degeneration were found to be significantly predictive of non-specific lower back pain for any of the joints considered. ConclusionsHot spots identified on SPECT are correlated with the presence of degeneration on CT but have limited diagnostic ability to identify potential causes of non-specific lower back pain.

Impact of patient body habitus on image quality and quantitative value in bone SPECT/CT.

The first edition of guidelines for standardization of bone single photon emission computed tomography (SPECT) imaging was published in 2017, and the optimization and standardization are widely promoted. To the purpose, clarification of the factors related to image quality and quantitative values and their influence are required. The present study aimed to clarify and optimize the influence of patient body habitus on image quality and quantitative values in bone SPECT/CT. National Electrical Manufacturers Association body phantom (S-size) and custom-made large body phantoms (M-size and L-size) that simulate the abdomens of Japanese patients weighing 60, 80, and 100kg, were used. Each phantom was filled with 99mTc-solutions of 108 and 18kBq/mL for the hot spheres and background, respectively. Dynamic SPECT acquisition was performed for 6000s (150s /rotation × 40 rotation). The data were divided into six projection data and reconstructed each acquisition time (150, 300, 450, 600, 750, 900s, and single projection 6000s). Image quality was evaluated for contrast (QH, 17mm), background noise (NB, 17mm), contrast-to-noise ratio (CNR), maximum standardized uptake value (SUVmax, 17mm), and visual assessment for a 17mm hot sphere. Image quality in the 300s acquisition showed that values of QH, 17mm, CNR, and SUVmax, 17mm decreased (-16.7%, -11.8%, and -11.3%) for M-size and (-28.2%, -30.1%, and -21.7%) for L-size compared with S-size, respectively. No significant difference was observed in NB, 17mm values. M-size and L-size required 1.2 and 2.3 times longer acquisition, to achieve same CNR as S-size. In visual assessment, 17mm hot sphere could not be detected only in the L-size. When the Japanese bone SPECT guidelines criteria were applied in 600s, the sphere could be detected between all phantoms. Patient body habitus significantly affects image quality and decreases the quantitative value in bone SPECT/CT. For the optimization, extend acquisition time according to the patient body habitus is effective for image quality. And for the standardization, it is important to achieve imaging conditions that meet the Japanese bone SPECT guidelines criteria to ensure adequate detectability.

Improvement of Quantitative Single-Photon Emission Computed Tomography Image Quality by the New Step-and-Shoot Scan Mode

The step-and-shoot (SS) mode and continuous mode are currently used for single-photon emission computed tomography (SPECT) scan mode, and a new scan mode that combines both modes, step-and-shoot plus continuous (SSC) mode, was developed. It is expected to allow a shorter scan time and lower injected dose because the SSC mode is more sensitive than the SS mode. We confirmed the image quality of this scan mode, including various quantitative correction methods for scatter (SC), attenuation (AC), and resolution recovery (RR) in a phantom study and clinical case study. Image quality was evaluated by the count, contrast-to-noise ratio (CNR), and percent of the coefficient of variation (%CV). Independent of the correction methods, the count, CNR, and %CV of the SSC mode were superior to those of the SS mode. The ACSCRR was the best method, with a maximum increased rate of 66.4% in counts and 57.8% in CNR for the 13-mm sphere and 19.6% in CNR for other sphere sizes. The %CV for the SSC mode was the best for AC and ACRR, which was at 15.1%. With regards to attaining short bone SPECT scan time, the combination of the SSC mode and ACRR or ACSCRR demonstrated the best physical performance.

Impact of Reduced Acquisition Time on Bone Single-photon Emission Computed Tomography Images in Oncology Patients.

Background:The use of resolution recovery (RR) in bone and myocardial perfusion imaging is becoming increasingly popular in nuclear medicine departments. RR produces reconstructed images that show improved spatial resolution and signal-to-noise ratio compared with conventional single-photon emission computed tomography (SPECT) images.Objective:To evaluate the impact of the ordered subset expectation maximization (OSEM) RR modality on preserving noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) for short SPECT acquisition.Methods:This prospective study was conducted on 80 patients. Full SPECT acquisition was performed as a standardized protocol, while reduced acquisition was achieved with the Poisson resampling method. Noise, SNR, and CNR were measured for different reconstruction parameters for the same image levels. The impact of surface area and body mass index was also measured for the same reconstruction parameters.Results:The results show significantly higher SNR and CNR for the Evolution for Bone protocol compared to the other two reconstruction protocols for full and reduced SPECT acquisition. With the shortening of the SPECT acquisition, an increase in the value of noise was recorded. SNR and CNR decreased with the reduction in SPECT acquisition.Conclusion:The Evolution for Bone protocol for all three analyzed acquisition protocols had the lowest noise values. The highest SNR and CNR were recorded in the Evolution for Bone protocol for the three acquisition protocols and SPECT acquisition time can be reduced from 20 to 10 min for bone SPECT.

Fast and Accurate Thoracic SPECT Image Reconstruction

In Single-Photon Emission Computed Tomography (SPECT), the reconstructed image has insufficient contrast, poor resolution and inaccurate volume of the tumor size due to physical degradation factors. Generally, nonstationary filtering of the projection or the slice is one of the strategies for correcting the resolution and therefore improving the quality of the reconstructed SPECT images. This paper presents a new 3D algorithm that enhances the quality of reconstructed thoracic SPECT images and reduces the noise level with the best degree of accuracy. The suggested algorithm is composed of three steps. The first one consists of denoising the acquired projections using the benefits of the complementary properties of both the Curvelet transform and the Wavelet transforms to provide the best noise reduction. The second step is a simultaneous reconstruction of the axial slices using the 3D Ordered Subset Expectation Maximization (OSEM) algorithm. The last step is post-processing of the reconstructed axial slices using one of the newest anisotropic diffusion models named Partial Differential Equation (PDE). The method is tested on two digital phantoms and clinical bone SPECT images. A comparative study with four algorithms reviewed on state of the art proves the significance of the proposed method. In simulated data, experimental results show that the plot profile of the proposed model keeps close to the original one compared to the other algorithms. Furthermore, it presents a notable gain in terms of contrast to noise ratio (CNR) and execution time. The proposed model shows better results in the computation of contrast metric with a value of 0.68 ± 7.2 and the highest signal to noise ratio (SNR) with a value of 78.56 ± 6.4 in real data. The experimental results prove that the proposed algorithm is more accurate and robust in reconstructing SPECT images than the other algorithms. It could be considered a valuable candidate to correct the resolution of bone in the SPECT images.

Bone SPECT/CT image fusion based on the discrete Hermite transform and sparse representation

Nuclear medicine imaging techniques have become fundamental modalities for metabolic evaluation of the human body. Single Photon Emission Computed Tomography (SPECT) is among the most used tools for functional image analysis. When combined with anatomical imaging such as Computed Tomography (CT), functional information can be analyzed with better performance since lesion localization can be substantially improved. In this paper, we present a transform-based fusion scheme applied to bone SPECT/CT image analysis. The method uses the discrete Hermite transform for image feature coding. It consists of a powerful mathematical tool that locally projects an input image onto the set of Hermite polynomials, providing low frequency and detail information. The image fusion is performed by using coefficients obtained from the transformation. Two different fusion strategies were designed based on coefficient content. Low frequency coefficients are fused through a sparse representation mechanism meanwhile coefficients with fine details are combined using local directional information and variance. Prior knowledge based on segmentation of bone tissues is included in the SR-based fusion rule. The final fused image is recovered by using the inverse transform from the resulting fused coefficients. The approach was evaluated with registered bone SPECT and CT images. It was also compared with other approaches of the state of art demonstrating its feasibility. We also present an evaluation of our method with brain tissues by using common images found in literature. Frequently used metrics were considered to quantitatively assess the performance of the proposed method.

Optimization of cross-calibration factor for quantitative bone SPECT without attenuation and scatter correction in the lumbar spine: head-to-head comparison with attenuation and scatter correction.

Quantitative single-photon emission computed tomography (SPECT) with computed tomography (SPECT/CT) is known to improve diagnostic performance. Although SPECT-alone systems are used widely, accurate quantitative SPECT using these systems is challenging. This study aimed to improve the accuracy of quantitative bone SPECT of the lumbar spine with the SPECT-alone system. The cross-calibration factor (CCF) was measured using three kinds of phantoms and the optimal values were determined. The recovery coefficient with and without attenuation and scatter correction (ACSC) were compared. Bone SPECT/CT was performed on 93 consecutive patients with prostate cancer, and the standardized uptake values (SUVs) were compared using the respective CCFs. The first 60 patients were classified according to body weight, and the correlation coefficient between SUVs with and without ACSC were calculated; the slopes were defined as body weight-based coefficients (BWCs). In the remaining 33 patients, the SUV was adjusted according to BWC, and the accuracy of the adjustment was verified. The quantitative SPECT values obtained from the CCF using SIM2 bone phantom showed nearly accurate radioactivity concentrations, even without ACSC. The recovery coefficients with and without ACSC were similar. Unadjusted SUVs with and without ACSC were strongly correlated; however, SUVs without ACSC were significantly higher than those with ACSC (P < 0.0001). The mean difference between the SUVs with and without ACSC disappeared when the SUVs without ACSC were adjusted by BWC (P = 0.9814). Our cross-calibration method for quantitative bone SPECT enables interpretation with a harmonized SUV even in SPECT-alone systems.

Image-Guided Right T10 Costotransverse Joint Resection for Costotransversitis: Operative Technique and Nuances: 2-Dimensional Operative Video

We describe the operative approach and management for costotransverse joint inflammation in a 49-yr-old man with worsening midthoracic pain radiating to the right paraspinal area. He underwent physical therapy with no relief of his symptoms. Thoracic spine magnetic resonance imaging (MRI) revealed severe arthritic changes involving the right T10 costotransverse joint. Scoliosis X-rays showed a dextroconvex curvature in the midthoracic spine, without any significant imbalance. Single-photon emission computed tomography (SPECT) scan revealed focal increased uptake of the right T10 costotransverse joint. T10 costotransverse joint lidocaine injection did not provide any relief. We performed a computed tomography (CT)-guided biopsy, which was negative for malignancy and also cultures were negative. MRI revealed a significant enhancement in this area and the patient's C-reactive Protein was elevated. Decision was made to perform open biopsy and costotransverse joint resection. We present a case of minimally invasive, image-guided costotransverse joint resection, which has not been described in the literature. The right T10 costotransverse joint was dissected out with the image-guided dilator, and tubular retractors were inserted. Under the microscope, using the image-guided drill, the right T10 costotransverse joint was drilled out. The lateral aspect of the right T10 process was drilled out as well as the medial-dorsal aspect of the right T10 rib. The patient recovered from surgery well with abatement of his preoperative thoracic pain, which remained abated at 6-mo follow-up. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation with a bone SPECT scan to help localize the pain generator. Patient consented for the procedures and for the publication of the video.

An alternative method for radioactivity measurement in quantitative bone SPECT/CT imaging.

Bone scintigraphy with combined single-photon emission computed tomography (SPECT) and computed tomography (CT) has become widely used for the detection of bone metastases. However, calculation of the semi-quantitative standardized uptake value (SUV) requires measurement of the pre- and post-injection radioactivity of the radiopharmaceutical. This study aimed to compare measured and fixed input radioactivity values for quantitative SPECT/CT bone imaging to examine whether the fixed measurement method of radiopharmaceutical radioactivity could be used as an alternative method. Four different methods were used to quantify the Tc-99m hydroxymethylene diphosphonate input radioactivity: (A) measured pre- and post-injection radioactivity values; (B) measured pre-injection and fixed post-injection radioactivity values; (C) fixed pre-injection and measured post-injection radioactivity values; (D) fixed pre- and post-injection radioactivity values. All SPECT/CT acquisitions were analyzed using bone SPECT analysis software, and the semi-quantitative parameters (SUVpeak and SUVmean) were recorded and compared for each analytical method. Two semi-quantitative parameters showed significant differences between analytical methods A and B, A and D, and C and D. However, an additional subgroup analysis performed on patients whose median post-injection measured radioactivity value was <1.5 MBq showed no significant differences in parameters between all analytical methods. Measurement of the radiopharmaceutical radioactivity can be an alternative method because it reduces the volume of radioactivity post-injection. The simplified fixed measurement method of radiopharmaceutical radioactivity can be used as an alternative method in cases when measuring the radioactivity in quantitative bone SPECT/CT imaging is missed.

Automatic quantification package (Hone Graph) for phantom-based image quality assessment in bone SPECT: computerized automatic classification of detectability.

We previously developed a custom-design thoracic bone scintigraphy-specific phantom ("SIM2 bone phantom") to assess image quality in bone single-photon emission computed tomography (SPECT). We aimed to develop an automatic assessment system for imaging technology in bone SPECT and demonstrate the validity of this system. Four spherical lesions of 13-, 17-, 22-, and 28-mm diameters in the vertebrae of SIM2 bone phantom simulating the thorax were filled with radioactivity (target-to-background ratio: 4). Dynamic SPECT acquisitions were performed for 15min; reconstructions were performed using ordered subset expectation maximization at 3-15-min timepoints. Consequently, 216 lesions (54 SPECT images) were obtained: 120 and 96 lesions were used for software development and validation, respectively. The developed software used statistical parametric mapping to rigidly register and automatically calculate quantitative indexes (contrast-to-noise ratio, % coefficient of variance, % detectability equivalence volume, recovery coefficient, target-to-normal bone ratio, and full width at half maximum). A detectability score (DS) was used to define the four observation types (4, excellent; 3, adequate; 2, average; 1, poor) to score hot spherical lesions. The gold standard for DSs was independently classified by three experienced board-certified nuclear medicine technologists using the four observation types; thereafter, a consensus regarding the gold standard for DSs was reached. Using 120 lesions for development, decision tree analysis was performed to determine DS based on the quantitative indexes. We verified the validation of the quantitative indexes and their threshold values for automatic classification using 96 lesions for validation. The trends in the automatically calculated quantitative indices were consistent. Decision tree analysis produced four terminal groups; two quantitative indexes (% detectability equivalence volume and contrast-to-noise ratio) were used to classify DS. The automatically classified DSs exhibited an almost perfect agreement with the gold standard. The percentage agreement and kappa coefficient were 91.7% and 0.93, respectively, in 96 lesions for validation. The developed software automatically classified the detectability of hot lesions in the SIM2 bone phantom using the automatically calculated quantitative indexes, suggesting that this software could provide a means to automatically perform detectability analysis after data input that is excellent in reproducibility and accuracy.

Quantitative evaluation of single-photon emission computed tomography findings in lower extremity possible without computed tomography-based attenuation correction.

For performing accurate quantitative analysis of single-photon emission computed tomography (SPECT)/computed tomography (CT) images, CT-based attenuation correction (CTAC) is considered to be necessary. However, the effect on quantitative values for an examined area close to the body surface, such as in the lower extremity, has yet to be elucidated. We performed the present investigation to determine the possibility of quantitative evaluation using a SPECT standalone device without CT. Validation was performed using clinical data of patients who underwent a lower extremity SPECT/CT examination, with grouping based on presence or absence of CTAC, scatter correction and resolution recovery. Using a reference group in which all types of correction were applied, standardized uptake values (SUVs), including maximum (SUVmax) and peak (SUVpeak), were examined in each group and compared. As compared to the reference group, the difference in quantitative values became smaller in the order of the applied scatter correction and resolution recovery, applied resolution recovery, applied scatter correction, and neither scatter correction or resolution recovery applied groups, with no significant difference between the reference group and that with neither scatter correction or resolution recovery applied. A similar tendency was seen for both SUVmax and SUVpeak. In bone SPECT quantitative examinations of the lower extremity, quantitative evaluation without CTAC is possible without the use of scatter correction or resolution recovery. Thus, quantitative evaluation can be performed with use of a standalone SPECT device without CT.

Added diagnostic value of SPECT to evaluate bone metastases inbreast cancer patients with normal whole body bone scan.

Background:In this research, we aimed to survey the added value of single photon emission computed tomography (SPECT) in comparison with planar whole body bone scan to visualize bone metastatic lesions in patients with breast cancer.Methods:A total of 80 patients with breast cancer (invasive ductal carcinoma) were examined with planar whole body bone scan and SPECT imaging using 99mTc-labelled methylene diphosphonate (99mTc-MDP). The patients with abnormal uptakes in SPECT imaging were also investigated with magnetic resonance imaging (MRI).Results:Among these 80 patients with normal whole body bone SPECT scan, 19 (23.25%) of them revealed abnormal 99mTc-MDP uptake in skeleton. Furthermore, these 19 patients were subjected to MRI and 3 (3.75%) of them were confirmed with metastatic bone lesion.Conclusion:The obtained data suggest that SPECT possess the added diagnostic over planar whole body bone scan.

SPECT/CT Correlation in the Diagnosis of Unilateral Condilar Hyperplasia.

Objective: To evaluate the correlation between metabolic bone activity measured by single photon emission computed tomography (SPECT) and the anatomic condylar characteristics acquired by computed tomography (CT), in patients with unilateral condylar hyperplasia (UCH). Method and Materials/Patients: Observational, descriptive study in a group of 71 patients with clinical diagnosis of UCH and indication of SPECT/CT. Bone SPECT images obtained in a gamma-camera GE Infina and processed in a station Xeleris 3 with the program Volumetrix MI Evolution for bone. CT images acquired in a PET/CT Biograph mcT20 equipment (Siemens) processed in a station Osirix V 7.5.1 (Pixmeo, Bomex, Switzerland). Results: The sample included 24 men (33.8%) and 47 women (66.2%). Active state UCH was detected in 40 (56.3%) cases (over 55% uptake in the affected condyle) and 38 (53.5%) presented mandibular deviation to the right side. No significant differences related to sex, age, or mandibular deviation side were found. Mandibular deviation was the only morphologic feature related to active/inactive UCH (p = 0.003). The likelihood of active CH was significantly higher in patients with mandibular deviation higher than 6 mm compared with <6 mm (odds ratio (OR): 3.51, confidence interval (CI) 95%: 1.27–9.72). Conclusion: There is a significant correlation between the magnitude of mandibular deviation quantified on CT and metabolic findings obtained by SPECT in patients with UCH. The risk of active UCH is 3.5 times higher in patients with a mandibular deviation ≥6 mm.

Quantitative bone single-photon emission computed tomography imaging for uninfected nonunion: comparison of hypertrophic nonunion and non-hypertrophic nonunion

BackgroundRecently, a standardized uptake value (SUV) has been used to evaluate bone single-photon emission computed tomography (SPECT). The aim of this study was to investigate quantitative SPECT imaging of uninfected nonunion to compare hypertrophic nonunion and non-hypertrophic nonunion using volume-based parameters.MethodsWe evaluated 23 patients with uninfected nonunion who underwent SPECT acquisition 3 h after an injection of 99mTc-hydroxymethylene diphosphonate or 99mTc-methylene diphosphonate from April 2014 to November 2019. We reconstructed the acquired data and performed voxel-based quantitative analysis using the GI-BONE software. Quantitative parameters, maximum SUV (SUVmax), peak SUV (SUVpeak), and mean SUV (SUVmean) in the high and low uptake areas of nonunion were compared between hypertrophic nonunion and non-hypertrophic nonunion. The contralateral limb was used as a control, and the ratios of the quantitative parameters were calculated.ResultsThe values for the quantitative parameters (high uptake area/low uptake area, respectively), SUVmax control ratio (12.13 ± 4.95/6.44 ± 4.71), SUVpeak control ratio (11.65 ± 4.58/6.45 ± 4.64), and SUVmean control ratio (11.94 ± 5.03/6.28 ± 4.95) for hypertrophic nonunion were higher than those for non-hypertrophic nonunion (7.82 ± 4.76/3.41 ± 2.09 (p = 0.065/0.12), 7.56 ± 4.51/3.61 ± 2.23 (p = 0.065/0.22), and 7.59 ± 5.18/3.05 ± 1.91 (p = 0.076/0.23)).ConclusionsSUVmax, SUVpeak, and SUVmean control ratios obtained from bone SPECT images can quantitatively evaluate the biological activity of nonunions and may be an effective evaluation method for treatment decisions, especially the necessity of autologous bone grafting.

Test-retest repeatability of quantitative bone SPECT/CT.

Technological innovations in single-photon emission computed tomography (SPECT) have enabled a more accurate quantitative evaluation of the uptake, and the standardized uptake value (SUV) can be measured as a semi-quantitative value, as in positron emission tomography. Nevertheless, the reliability of the SUV of bone SPECT has not been well established. The purpose of this study is to evaluate the test-retest repeatability of the SUV of bone SPECT/CT in clinical settings. This prospective study recruited patients with prostate cancer planning to receive bone SPECT/CT for the evaluation of bone abnormality between August 2017 and September 2019. Bone images were acquired twice by an integrated SPECT/CT scanner (Symbia Intevo, Siemens) within a 4- to 10-day interval. The maximum SUV (SUVmax) and peak SUV (SUVpeak) were calculated for the volumes of interests on the normal bone areas, degeneration/fracture lesions, and metastatic lesions. To determine repeatability, we calculated statistical indicators, including intraclass correlation coefficient (ICC), repeatability coefficient (RC), and mean absolute percentage difference (MAPD). For the ICC, the 95% confidential interval (CI) was also calculated, and an ICC of ≥ 0.8 was defined as an almost perfect correlation. Twelve male patients were enrolled in the study (58-86years; median, 71years), and a total of 229 volumes of the interest were included in the analyses. The ICCs were 0.968 [95% CI (0.959, 0.975)] for SUVmax and 0.976 [95% CI (0.969, 0.981)] for SUVpeak. The RCs of the relative difference were 30.7% for SUVmax and 27.6% for SUVpeak, and the MAPDs (± standardized deviation) of all lesions were 12.3 ± 9.9% for SUVmax and 11.5 ± 8.3% for SUVpeak. The RCs and the MAPDs showed comparable value with the previous report regarding repeatability studies on PET. An almost perfect correlation was demonstrated by repeated SUVmax and SUVpeak measured by quantitative integrated SPECT/CT. The quantitative values could be reliable indicators in patient management.

Validation of the influence of CT slice thickness on the quantitative accuracy and image quality of single photon emission computed tomography.

Computed tomography (CT) images are used for precise anatomical location of lesions and for accurate attenuation correction in single-photon emission computed tomography (SPECT) image reconstruction in SPECT/CT examination. The aim of this study was to verify the effects of varying CT collimation width and slice thickness on CT images and on CT attenuation corrected SPECT images. We acquired SPECT/CT images of a micro-coin phantom and the National Electrical Manufacturers Association body phantom filled with 99mTc-pertechnetate while varying the abovementioned CT parameters. The full width at half maximum of the slice sensitivity profile, the standard deviation of CT image background noise, and the radiation dose from CT scans were evaluated. Subsequently, the percentage contrast, background variability, and absolute recovery coefficient of the SPECT image were measured. Furthermore, we retrospectively reviewed the clinical bone SPECT images of 23 patients, and statistical testing of differences was performed. As the collimation width and reconstruction slice thickness of the CT image increased, z-axis resolution deteriorated, and background noise decreased. In addition, CT radiation dose decreased with increasing collimation width. Meanwhile, SPECT image quality and quantitative accuracy were unchanged with varying CT collimation width and slice thickness. There were no notable variations in clinical SPECT images and no statistically significant differences. When high-resolution CT slices on the z-axis are not required for clinical diagnosis, increasing collimation width or slice thickness can reduce the radiation dose and image noise with no influence on the quality of SPECT images .

Quantitative bone SPECT analysis of mandibular condyles in an asymptomatic population: an approach to normal reference values

Bone scintigraphy is an extremely valuable technique in diagnosis and treatment planning for patients with condylar hyperplasia (CH). The main objective of this study was to develop an approach to determine normal activity values in the mandibular condyles, adjusted to age and sex, through quantitative analysis of bone single-photon emission computed tomography (SPECT) on a condyle-by-condyle basis and to compare these values with those of a control group comprising patients with confirmed CH. Technetium 99 m-methylene diphosphonate (99mTc-MDP) SPECT studies of the mandibular condyles were performed in patients with no mandibular pathology for quantitative analysis. Regions of interest were drawn on slices representing the upper, middle, and inferior thirds of each condyle and on the summation of transaxial slices representing the whole condyle (three-dimensional approach). The clivus was used for internal validation and the condyle to clivus ratios were calculated. These ratios were compared between ‘normal’ and ‘diseased’ condyles. A total 144 condyles in normal patients and 25 in confirmed CH patients were analysed. Differences between the ratios were evaluated through the coefficient of variation. In normal patients, the ratios to the clivus on the summed condyle image showed the lowest variability: range 0.3–1.28 (median 0.74). The quantile regression model showed significant differences with respect to sex, but not to age. The Mann–Whitney test showed significant differences in the ratios to clivus between normal and diseased condyles (P<0.0001).