Comparison of effects of absolute scatter correction and relative scatter correction on image quality in PET reconstruction / 中华核医学与分子影像杂志

Objective:To study the impact of different scattering correction algorithms in the reconstruction of PET/CT images on image artifacts and the precision of quantitative parameters.Methods:The phantom as described in the National Electrical Manufacturers Association (NEMA) NU2 standard was filled with 18F. The background activity was fixed, and the activity of the solution in the spheres was adjusted to obtain several configurations, including the normal ratio group (4.08∶1) and the extreme ratio group (200∶1). The surface contamination group with the same ratio as the extreme ratio group contained a small radioactive source with different doses of 18F (74, 37, 3.7 and 0.37 MBq) placed at the surface of the phantom. PET/CT images of 30 patients (21 males, 9 females, age: (44.5±10.2) years) from Peking University Cancer Hospital & Institute between July 2012 and December 2021 were retrospectively analyzed, including 10 with normal images ( 18F-FDG) and 20 with abnormal images (10 with dislocation during acquisition, 10 with surface contamination). The images were reconstructed with relative and absolute scattering correction. The phantom was evaluated using the target to background ratio (TBR) and the artifact classification. CV as well as the artifact classification were used to compare the clinical image quality. Mann-Whitney U test and χ2 test were used to analyze data. Results:In the normal ratio group and the extreme ratio group, the TBRs of phantom images reconstructed with relative correction were significantly higher than those with absolute correction (normal ratio group: 3.30(1.94, 4.53) vs 2.72(1.56, 3.56); z=-2.20, P=0.028; extreme ratio group: 105.47(45.62, 162.82) vs 101.36(43.96, 155.57); z=-1.99, P=0.046). In the surface contamination group, with the increase of the activity of the small source, the artifact became more obvious, and the artifact classification score of absolute correction was significantly better than that of relative correction (1.5(1.0, 2.0) vs 2.5(2.0, 3.0); z=-2.00, P=0.046). In the 10 normal 18F-FDG PET/CT patients, the CVliver of the relative correction (9.67%(8.00%, 11.00%)) was significantly lower than that of absolute correction (11.00%(9.00%, 12.00%); z=-2.57, P=0.010), indicating the higher image quality of images with relative correction. In abnormal images, the image quality of absolute correction was significantly higher than that of relative correction with fewer and less severe artifacts (dislocation cases: 9/10 vs 4/10; χ2=5.50, P=0.019; surface contamination cases: 9/10 vs 4/10; χ2=5.50, P=0.019). Conclusions:The relative scattering correction is suitable for normal situations in clinical PET acquisition. However, with dislocation or surface contamination, the absolute scattering correction helps to reduce the artifacts and improve the image quality.

Predictive value of postoperative hypolordosis in the occurrence of adjacent segment disease after lumbar fusion surgery / 中华骨科杂志

Objective:To investigate the value of relative lumbar lordosis (RLL) and lumbar distribution index (LDI) in predicting the occurrence of adjacent segment disease (ASDis) after lumbar fusion surgery.Methods:This study retrospectively reviewed 163 consecutive patients (58 males and 105 females) who had undergone lumbar fusion and had been followed over 2 years,with an average age of 58.7 years; among them, 74, 71, and 18 patients had undergone fusion of one-level, two-level, and three-level, respectively. They were divided into the non-ASDis group and ASDis group based on the presence of ASDis or not. Pre- and post-operative spinopelvic parameters were measured on the upright lateral radiographs. RLL was calculated as measured lumbar lordosis (LL) minus ideal LL, and LDI was calculated as the ratio of postoperative low lumbar lordosis (LLL) to LL. Each parameter was stratified into 1 "aligned" subgroup and 3 "disproportioned" subgroups in accordance with values. Cochran-Armitage test of trend andlogistic analysis were performed to investigate the association between these two parameters and the occurrence of ASDis.Results:The average follow-up duration after initial surgery was 46±14 months (range, 25 to 134 months). Twenty-four (14.7%) patients were diagnosed as ASDis. The age ( t=3.13, P=0.002) and the proportion of 2-level and 3-level fusion (χ 2=10.27, P=0.006) in the ASDis group were significantly higher than those in the non-ASDis group ( P<0.05). There were no statistically significant differences between groups with respect to other general data. The ratios of moderate and severe hypolordosis of RLL were significantly higher in the ASDis group than that in the non-ASDis group (χ 2=16.92, P<0.001). There was also a significant linear trend with higher degree of hypolordosis being associated with higher rates of ASDis. However, distribution of four statuses of LDI did not differ statistically between groups. After controlling the confounders, the logistic regression analysis revealed that age, odd ratio ( OR)=1.07, 95% CI: (1.01, 1.13), P=0.018), moderate[ OR=4.34, 95% CI: (1.03, 18.41), P=0.046] and severe hypolordosis [ OR=11.64, 95% CI: (1.30, 104.49), P=0.028] were significantly associated with the occurrence of ASDis. Conclusion:A significant association between postoperative RLL and occurrence of ASDis after lumbar fusion surgery were detected. Setting surgical goals according to RLL may help reduce the ASDis rate. However, LDI is not identified to be predictive factors of the occurrence of ASDis.

Comparative study of 68Ga-DOTATATE and 18F-FDG PET/CT imaging in the detection of bone metastasis in neuroendocrine neoplasm / 中华核医学与分子影像杂志

Objective:To compare the value of 68Ga-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid- D-Phe1-Tyr3-Thr8-octreotide (DOTATATE) and 18F-fluorodeoxyglucose (FDG) PET/CT imaging in the detection of bone metastasis in neuroendocrine neoplasm (NEN). Methods:From January 2014 to July 2019, 29 NEN patients (19 males, 10 females, age: 35-76 years) with bone metastasis who underwent 68Ga-DOTATATE and 18F-FDG PET/CT imaging within one month in Peking University Cancer Hospital & Institute were retrospectively enrolled. Patients were divided into Ki-67≤20% and Ki-67>20% groups according to the tumor proliferation activity, and osteolysis, osteogenesis and no change groups according to the CT findings of bone metastases. The differences of the number and radioactive uptake (maximum standardized uptake value (SUV max) ratio of bone lesion to normal bone (SUV T/B)) of detected bone metastases between 68Ga-DOTATATE and 18F-FDG PET/CT imaging were analyzed. χ2 and Mann-Whitney U tests were used to analyze the data. Results:The sensitivity of 68Ga-DOTATATE and 18F-FDG PET/CT imaging were 75.9%(22/29) and 82.8% (24/29) respectively, and there was no significant difference between the two modalities ( χ2=0.42, P>0.05). The numbers of cases with bone lesions detected by 68Ga-DOTATATE PET/CT imaging in pelvis, spine, ribs, proximal limbs, sternoclavicular scapula and skull were all higher than those of 18F-FDG PET/CT imaging (23, 22, 20, 14, 14, 10 vs 12, 19, 13, 11, 10, 6, respectively). The 68Ga-DOTATATE PET/CT imaging was significantly superior to 18F-FDG imaging in detecting bone metastases (9(3, 36) and 3(0, 18)) and SUV T/B(11.10(3.35, 22.30) and 1.60(1.05, 2.70); U values: 281.000, 77.000, both P<0.001). 68Ga-DOTATATE PET/CT imaging found more bone lesions in well differentiated NEN (Ki-67≤20%) group (11(2, 38) and 2(0, 13)) and osteogenic bone metastasis group (31(3, 100) and 3(0, 31); U values: 105.500, 69.500, both P<0.05). SUV T/B of 68Ga-DOTATATE PET/CT imaging was significantly higher than 18F-FDG PET/CT imaging in all subgroups ( U values: 3.000-22.000, all P<0.05). Conclusion:The 68Ga-DOTATATE PET/CT imaging is superior to 18F-FDG PET/CT imaging in the detection of bone metastasis in NEN.

The outcome and countermeasure of posterior correction surgery for severe kyphoscoliosis secondary to spinal Gorham disease / 中华骨科杂志

Objective:To investigate the outcome of posterior correction surgery for severe kyphoscoliosis secondary to spinal Gorham disease, further to explore the countermeasure in such complicated condition.Methods:From January 2005 to December 2019, a total of 12 consecutive patients were diagnosed with spinal Gorham disease. Four patients who had undergone correction surgery were reviewed retrospectively. There were 3 males and 1 female. The median age of surgery was 14.5 years (11.5 years, 27.5 years), with the median of Cobb angle of scoliosis and kyphosis 29° (21.5°, 78.0°) and 94° (78.0°, 103.0°), respectively. After Halo-gravity traction, one-stage posterior correction surgeryand Schwab grade I or II osteotomy, with pedicle screw fixation bridging the diseased vertebrae was performed. Drug therapy of bisphosphonate was recommended after surgery. The Cobb angle of scoliosis and kyphosis, coronal and sagittal balance were measured on the standing upright radiographs of the spine. CT and MRI were used to give precise evaluation of spinal and peripheral soft tissue involvement.Results:After Halo-gravity traction of 3 months (2.5 months, 3.5 months), the median of Cobb angle of scoliosis decreased to 23.5° (15.5°, 77.0°) and kyphosis decreased to 65° (57°, 83.5°) respectively. Two patients underwent facetectomyand 2 received Ponte osteotomy. The median operative time and blood loss were 5.5 h (5.1 h, 5.9 h) and 3 095ml (2 950 ml, 3 320 ml), with the fusion segment of 13.5 (12.5, 14.5) and the fixation density of 47.8% (40.9%, 57.3%). After surgery, the median of Cobb angle of scoliosis and kyphosis decreased to 18° (10.5°, 38.5°) and 59° (42.0°, 78.0°). Compared to the values before traction, the median of correction rates of scoliosis and kyphosis after surgery were 46.7% (33.1%, 59.5%) and 35% (12.3%, 51.1%) respectively. Moreover, the median of coronal balance decreased from 15.5 mm (9.0 mm, 21.0 mm) to 6.5 mm (4.0 mm, 9.0 mm), while the median of sagittal balance decreased from 14 mm (-18.0 mm, 27.5 mm) to 5.5 mm (-5.5 mm, 12.5 mm). During a median of follow-up of 2.8 years (2.0 years, 3.5 years), no complication was detected except one patient whounderwent revision surgery for rod broken.Conclusion:One-stage posterior correction surgery combined with preoperative halo-gravity tractionand postoperative anti-osteoporosis therapydemonstratedto be safe and effective for severe kyphoscoliosis secondary to spinal Gorham disease. More attention should be paid to the failure of internal fixation after surgery.

Incidence and management of deep surgical site infection following spinal deformity surgery: 8 818 cases at a single institution / 中华骨科杂志

Objective:To investigate the incidence and management of deep surgical site infection(SSI) after the spinal deformity surgery.Methods:This study retrospectively reviewed a consecutive cohort of 8818 patients with spinal deformity who received spinal deformity surgery between January1998 and December 2017 at our center. The diagnosis of deep SSI was based on the clinical symptoms, imaging data and laboratory findings. Early infection and late infection were defined as deep infections occurring <3 months and >3 months after the initial procedure, respectively. All deep SSIs were first treated with irrigation and debridement, closed suction irrigation system and antibiotics. If the infection cannot be eradicated, dressing change is recommended within 2 years after the initial surgery. The instrumentation can be removed 2 years after the initial surgery with careful evaluation of the fusion mass. The posterior-anterior and lateral radiographs were used to measure the coronal parameters and sagittal alignment.Results:Sixty patients were diagnosed as deep SSI after spinal deformity surgery, including 11 patients with early infection and 49 patients with late infection. No significant difference was observed in terms of age, gender ratio, surgical approach and fusion levels between the two groups. Deep SSI seemed to be more likely to occur between 2 and 5 years after surgery. Incidence of SSI was lowest in the patients with idiopathic scoliosis and ankylosing spondylitis, and highest in the patients with neuromuscular and syndromic scoliosis. There was a high rate of negative culture in the primary culture. Staphylococcus aureus and Escherichia coli were the most common organisms in the early infection, while patients with late infection had a high rate of low-virulent skin flora. In the early infection group, nine patients retained instrumentation while the implants were removed 2 years after the primary surgery in 2 patients. In patients with late infection, instrumentation was retained in 5 cases and removed in 10 cases until 2 years after the primary surgery. 34 cases were infected 2 years after the primary surgery and the implants were removed directly. One patient underwent reoperation with instrumentation 1 month after implant removal, another patient underwent reoperation 3 years after implant removal due to progression of deformity. Significant loss of coronal correction was noted at the latest follow-up.Conclusion:The rate of deep SSI after spinal deformity surgery was 0.68%, of which the incidence of early infection and delayed infection was 0.12% and 0.56%, respectively. An increased risk of SSI in patients with neuromuscular and syndromic scoliosis was noted. If the infection cannot be eradicated after repeated debridement, we recommend instrumentation removal 2 years after the initial surgery, but there is still a high risk of loss of correction in these patients.

The long-term results of growth friendly non-fusion technique in the treatment of early-onset scoliosis / 中华骨科杂志

Objective:To evaluate long-term results of growth friendly non-fusion technique (GF) in the treatment of early-onset scoliosis (EOS).Methods:From August 2008 to October 2019, a total of 26 EOS patients (mean age 7.2±2.4 years old) who had completed surgery with GF treatment, including 12 males and 14 females, were reviewed retrospectively. Among them, 16 patients underwent growing rod treatment while 10 patients underwent vertical expandable prosthetic titanium rib (VEPTR) treatment. All patients had minimum 2 lengthening procedure during distraction period and over 2-year follow-up after graduation. Radiographic data were collected before and after index surgery as well as at graduation and the latest follow-up. Complications were also recorded during distraction period and after graduation.Results:A total of 145 lengthening procedures were performed in 26 patients, averagely 5.6 procedures per patient. The mean age at graduation was 12.6±1.6 years old. The average follow-up was 4.7±1.4 years duringdistraction period, and 2.9±0.9 years after graduation.The main Cobb angle was significantly decreased from 81.2°±17.3° to 41.1°±13.1°( t=8.124, P<0.001)after the index surgery, but slightly increased to 48.8°±15.4° at the end of distraction. After definitive spinal fusion, the main Cobb angle was notably decreased from 52.8°±16.1° to 45.4°±14.8° in 16 patients( t=2.415, P=0.035), with an average correction rate of 14.1%±9.4%. At the latest follow-up, the main Cobb angle was 45.2°±15.6° and the average correction rate was 44.3%±15.5% when comparing with the value before the index surgery. The thoracic and spinal height were significantly increased after initial surgery. During distraction period, the average gain of thoracic and spinal height was 3.3±0.9 cm and 5.6±1.9 cm, with the growth rate of 0.6±0.3 cm and 1.0±0.4 cm per distraction, respectively. A total of 36complications were recorded in 14 patients. There were 27 complications occurred during distraction period and 9 after graduation. Conclusion:Surgical management of EOS with growing rod and VEPTR could effectively correct the spinal deformity and maintain spinal growth. The complication rate after graduation was relative lower than distraction period. However, the correction of definitive spinal fusion during graduation was relative lower.

Outcome of traditional growing rods for correction of apical vertebra rotation in early-onset scoliosis / 中华外科杂志

Objective@#To evaluate the correction result of traditional dual growing rods on apical vertebral rotation.@*Methods@#This study recruited 19 early-onset scoliosis patients (6 boys and 13 girls) who had received traditional dual growing rods treatment at Department of Spine Surgery, Nanjing Drum Tower Hospital from January 2009 to July 2015. The age at initial surgery was (5.7±1.7)years(range, 3 to 9 years). Measurements of primary curve magnitude, height of T1-S1, apical vertebral translation(AVR), apical vertebral body-rib ratio, apical vertebral rotation, thoracic rotation and rib hump were compared between pre-operatively, post-operatively, and at latest follow-up, through a paired-t test. Pearson correlation test was used for correlation analysis between parameters.@*Results@#All patients had a follow-up of (49.5±12.8)months(range, 24 to 71 months). A total of 111 operative procedures were performed, among which there were 92 lengthening procedures, averagely 4.8 lengthening procedures per patient. The average interval for each lengthening procedure was 10 months. The Cobb angle of primary curve was notably decreased from (66.5±13.2)° to (35.2±10.9)°(t=24.013, P<0.01), and no significant correction loss was found at the latest follow-up ((36.7±10.7)°)(t=-1.324, P=0.202). In addition, significant correction of AVR, thoracic rotation, apical vertebral translation, apical vertebra body-rib ratio, and rib hump were noted after initial surgery. Whereas, these parameters significant increased during follow-up(all P <0.05) except for thoracic rotation. Pearson correlation analysis showed that the increase of AVR during follow-up significantly correlated with change of apical vertebra translation, apical vertebral body-rib ratio, and rib hump(r=0.652, 0.814, 0.695; all P<0.05).@*Conclusions@#Significant correction of AVR can be achieved after initial surgery in early-onset scoliosis patients treated with traditional dual growing rods. However, such a technique can hardly prevent the deterioration of AVR during follow-up.

Application value of18F-FDG PET/CT in evaluating post-operative recurrence and metastasis of penile squamous cell carcinoma / 肿瘤

Objective: To explore the value of fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT imaging in monitoring postoperative recurrence and metastasis of penile squamous cell carcinoma. Methods: A total of 50 patients with penile squamous cell carcinoma received therapy in Peking University Cancer Hospital from May 2011 to June 2017 were collected as the study subjects. The PET/CT imaging was used to monitor the recurrence and metastasis of tumor, while the pathology result and follow-up data were considered as the gold standard. Results: Based on the pathology result and follow-up data,18F-FDG PET/CT imaging results showed 31 of the 50 patients had recurrence and metastases.18F-FDG PET/CT positive imaging was found in 36 patients with 6 false positive cases, and18F-FDG PET/CT negative imaging was found in 14 patients with 1 false negative case. The sensitivity, specificity and accuracy of18F-FDG PET/CT were 96.8%, 68.4% and 86.0%, respectively; the false positive rate and the false negative rate were 31.6% and 3.2%, respecively; the positive predictive value and the negative predictive value were 83.3% and 92.9%, respecively. A total of 60 lesions were detected in 31 patients with recurrence and metastases. There was no significant difference in maximum standard uptake value (SUVmax) among the metastatic tumors of different sites (P = 0.088). The SUVmax had no significant difference between the true positive lymph nodes and the false positive lymph nodes (P = 0.195). The recurrence and metastasis rates of the TNM stage III- patients older than 60 years of age were higher than those of the TNM stage -Ⅱ patients younger than 60 years of age (both P < 0.05). Conclusion: The18F-FDG PET/CT examination has high sensitivity and accuracy for the diagnosis of postoperative recurrence and metastasis of penile squamous cell carcinoma, but there are still some false positive results.