Experimental system for perfusion imaging and time-intensity processing based on ultrasound contrast agent

Objective： To present a self-developed experimental system for basic studies of blood perfusion imaging and time-intensity evaluating based on ultrasound contrast agent. Methods ： The experimental system performed the image reconstruction and time-intensity processing with radio frequency signals. The system was comprised of ultra-high speed hardware data acquisition interface and low computational cost algorithms. The self-made contrast agent ,blood mimic phantom and capillary phantom model were used to validate the experimental system. Results： The images acquired in blood phantoms with linear-array and curve-array transducers were given. The time-intensity curves corresponding to selected region of interestsequence were demonstrated. It was also shown the time-intensity based decay curves and a decay of ultrasound contrast agent under different ultrasound powers. Conclusion： Several suited from two in vitro phantom models show that the experimental system can be used to f blood perfusion and further clinical studies of microvasculature perfusion.     

Three-dimensional reconstruction of digitized human liver: based on Chinese Visible Human

Background Comparing with two dimensional （2D） imaging, both in diagnosis and treatment, three dimensional （3D） imaging has many advantages in clinical medicine. 3D reconstruction makes the target easier to identify and reveals the volume and shape of the organ much better than 2D imaging. A 3D digitized visible model of the liver was built to provide anatomical structure for planing of hepatic operation and for realizing accurate simulation of the liver on the computer. Methods Transverse sections of abdomen were chosen from the Chinese Visible Human dataset. And Amira software was selected to segment and reconstruct the structures of the liver. The liver was reconstructed in three-dimensions with both surface and volume rendering reconstruction. Results Accurately segmented images of the main structures of the liver were completed. The reconstructed structures can be displayed singly, in small groups or as a whole and can be continuously rotated in 3D space at different velocities. Conclusions The reconstructed liver is realistic, which demonstrates the natural shape and exact position of liver structures, tt provides an accurate model for the automated segmentation algorithmic study and a digitized anatomical mode of viewing the liver.     

Automated lung segmentation algorithm for CAD system of thoracic CT

Objective： To design and test the accuracy and efficiency of our lung segmentation algorithm on thoracic CT image in computer-aided diagnostic （CAD） system, especially on the segmentation between left and right lungs. Methods： We put forward the base frame of our lung segmentation firstly. Then, using optimal thresholding and mathematical morphologic methods, we acquired the rough image of lung segmentation. Finally, we presented a fast self-fit segmentation refinement algorithm, adapting to the unsuccessful left-right lung segmentation of thredsholding. Then our algorithm was used to CT scan images of 30 patients and the results were compared with those made by experts. Results： Experiments on clinical 2-D pulmonary images showed the results of our algorithm were very close to the expert＇s manual outlines, and it was very effective for the separation of left and right lungs with a successful segmentation ratio 94.8%. Conclusion： It is a practicable fast lung segmentation algorithm for CAD system on thoracic CT image.     

Combination of medial patellofemoral ligament reconstruction with vastus medialis advancement for chronic patellar dislocation

Background The medial patellofemoral ligament （MPFL） reconstruction is popular in clinical practice for chronic patellar dislocation; however, the combination with vastus medialis advancement is rare. The aim of this study was to evaluate the clinical outcome of the combination of MPFL reconstruction with vastus medialis advancement.Methods We retrospectively analyzed 69 patients with chronic patellar dislocation between July 2004 and October 2008： twenty eight cases with isolated MPFL reconstruction （group Ⅰ）, forty one cases with the combination of MPFL reconstruction with vastus medialis advancement （group C）. All patients had CT scans available for review with knee flexion at 30 degree, on which the congruence angle, patellar tilt angle and patellar lateral shift were measured. Physical apprehension tests were examined and the redislocation was recorded. In addition, knee function was evaluated using the Kujala score and subjective questionnaires.Results Patients were followed up for a mean of 42 months （12-65 months） without a recurrent dislocation reported.Postoperatively, all indexes on CT scan were within the normal range without a statistical difference between the two groups. Results from the apprehension test showed eight patients in group Ⅰ and three in group Chad patellar lateral shift exceeding 1.5 cm with a hard end point （P 〈0.05）. The Kujala score improved significantly from 51.3±4.5 to 79.9±6.2 in group Ⅰ and from 53.7±5.2 to 83.9±6.5 in group C （P 〉0.05）. However, the subjective questionnaire revealed a significant difference （P 〈0.05）, including 12 excellent, seven good and nine fair in group Ⅰ and 30 excellent, six good and five fair in group C.Conclusion The combination of MPFL reconstruction with vastus medialis advancement is better than isolated reconstruction to improve the subjective effects and decrease the patellar instability rate for chronic patellar dislocation.     

Stereotactic localization and visualization of the subthalamic nucleus

Background The subthalamic nucleus （STN） is widely recognized as one of the most important and commonly targeted nuclei in stereotactic and functional neurosurgery. The success of STN surgery depends on accuracy in target determination. Construction of a digitaiized atlas of STN based on stereotactic MRI will play an instrumental role in the accuracy of anatomical localization. The aim of this study was to investigate the three-dimensional （3D） target location of STN in stereotactic space and construct a digitalized atlas of STN to accomplish the visualization of the STN on stereotactic MRI, thus providing clinical guidance on the precise anatomical localization of STN. Methods One hundred and twenty healthy people volunteered to be scanned by 1.5 Tesla MRI scanning with 1-mm-thick slice in the standard stereotactic space between 2005 and 2006. One adult male was selected for 3D reconstruction of STN. The process of 3D reconstruction included identification, manual segmentation, extraction, conservation and reconstruction. Results There was a significant correlation between the coordinates and age （P 〈0.05）. The volume of left STN was significantly larger than the right STN, and there was a significant negative correlation between volume and age （P 〈0.05） The surface of the STN nucleus after 3D reconstruction appeared smooth, natural and realistic. The morphological feature of STN on the individual brain could be visualized directly in 3D. The 3D reconstructed STN could be rotated, zoomed and displayed at any direction in the stereotactic space. The anteroposterior diameter of the STN nucleus was longer than the vertical and transverse diameters in 3D space. The 3D reconstruction of STN manifested typical structure of the ＂dual lens＂. Conclusions The visualization of individual brain atlas based on stereotactic MRI is feasible. However, software for automated segmentation, extraction and registration of MR images need to be further developed.     

Clinical outcome of dental implants placed in fibula-free flaps for orofacial reconstruction

Background Functional reconstruction of the jaw defect due to tumor resection poses a challenging problem in maxillofacial surgery. The osteocutaneous fibula free flap in combination with simultaneous or second stage insertion of dental implants has exhibited growing popularity for such reconstructions. This study was aimed at evaluating the clinical status and the success rates of dental implants inserted in fibula-free flaps for orofacial reconstruction following ablation of tumors. Methods We conducted a clinical follow-up study based on 29 patients after oral tumor surgery, who received vascularized fibula bone grafts and endosseous implants for functional jaw reconstruction during a 5-year period. The follow-up protocol included clinical examination and radiological evaluation. The clinical records of the patients were reviewed retrospectively. Information on treatment modalities, dentition, implant parameters, and prostheses was collected and analyzed. Results In general, a high primary stability for implants placed into the free fibula grafts was achieved. The 1-year and 5-year cumulative survival rates of the implants were 96% and 91%, respectively, using the Kaplan-Meier method. The 1-year and 5-year cumulative success rates of implants respectively. The main reasons for failure of the dental proliferation. The fibula flap presents many advantages for implant-supported prosthetic rehabilitation difficult. placed into the fibula bone grafts were 95% and 87%, replants were infection, tumor recurrence and soft tissue implant placement, but its limited height sometimes makes Conclusions Vascularized fibula bone grafts provide a firm basis for the placement of dental implants in jaw reconstruction. Implants placed in fibula bone grafts were shown to integrate normally. The double-barrel technique, or increasing the height of the fibula flap by vertical distraction osteogenesis before implant placement in the mandible, is desirable from a functional and esthetic point of view.     

Original article： Anterior and middle skull base reconstruction after tumor resection

Background Surgical management of skull base tumors is still challenging today due to its sophisticated operation procedure. Surgeons who specialize in skull base surgery are making endeavor to promote the outcome of patients with skull base tumor. A reliable skull base reconstruction after tumor resection is of paramount importance in avoiding life-threatening complications, such as cerebrospinal fluid leakage and intracranial infection. This study aimed at investigating the indication, operation approach and operation technique of anterior and middle skull base reconstruction. Methods A retrospective analysis was carried out on 44 patients who underwent anterior and middle skull base reconstruction in the Department of Neurosurgery at Beijing Tiantan Hospital between March 2005 and March 2008. Different surgical approaches were selected according to the different regions involved by the tumor. Microsurgery was carried out for tumor resection and combined endoscopic surgery was performed in some cases. According to the different locations and sizes of various defects after tumor resection, an individualized skull base soft tissue reconstruction was carried out for each case with artificial materials, pedicled flaps, free autologous tissue, and free vascularized muscle flaps, separately. A skull base bone reconstruction was carried out in some cases simultaneously. Results Soft tissue reconstruction was performed in all 44 cases with a fascia lata repair in 9 cases, a free vascularized muscle flap in 1 case, a pedicled muscle flap in 14 cases, and a pedicled periosteal flap in 20 cases. Skull base bone reconstruction was performed on 10 cases simultaneously. The materials for bone reconstruction included titanium mesh, free autogenous bone, and a Medpor implant. The result of skull base reconstruction was satisfactory in all patients. Postoperative early-stage complications occurred in 10 cases with full recovery after conventional treatment. Conclusions The specific characteristics of skull base defects in various regions require different reconstruction materials and methods. The individualized reconstruction based on different skull base defects can achieve satisfactory results.     

Experimental replacement of thoracic esophageal segment with a biomaterial artificial esophagus in dogs

Objective：To implant 80 mm-long artificial esophagi constructed of biomaterial in dogs, observe the perioperative survival rates and the incidence of postoperative complications, and study the mechanisms of postoperative healing. Methods： Specimens of the implanted esophagus, the ＂neo-esophagi＂, were taken for histopathologic study 1, 3, 6, 12, 24 months after operation. Results： The incidence of anastomotic leakage after the artificial esophagus implantation was 3.33%. The perioperative survival rate was 96.67%. The incidence of postoperative stenosis in the ＂neo-esophagi＂ was 81.48%; the stenoses were treated by expanding with esophagoscopy and implanting a stent. Epithelization of the mucosa in the ＂neo-esophagi＂ was completed in 3 to 6 months after surgery Structures such as submucosal muscle layers, mucous glands, nerve fibers, capillaries, etc. were regenerated after 12 months, and then reconstruction of the fibrous connective tissue layer was completed. Conclusion： Implanting a biomaterial artificial esophagus accomplishes safe reconstruction of defects in the esophagus. Advanced cellular structure of ＂neo-esophagus＂ can be regenerated after 1 year. Postoperative stenosis, which is related to hyperplasia and retraction of scar tissue, is still the most common complications which limiting the clinical application of the artificial esophagus.     

Influence of tube voltage on digitized image qualityof patients exposed to occupational dust: phantoms and clinical studies

Background High-voltage analog X-ray examination is a main tool for pneumoconiosis,which is challenged by digital radiography （DR）.The tube voltage of DR chest films required for diagnosis and staging of pneumoconiosis is concerned technically.We investigated the influence of the tube voltage on chest X-ray DR image quality of patients exposed to occupational dust.Methods DR images of the CDRAD2.0model,an anatomical chest phantom,and 136 exposed workers were analyzed at different tube voltages by threereaders.Image quality factors （IQF） were calculated and compared using the CDRAD2.0 model.DR images of ten anatomic positions were scored against those of the high-kilovolt chest films in anatomical phantom and clinical cases,and differences in scores were analyzed.Results In the CDRAD2.0 model,all three readers had a minimal IQF at 120 kV （mean：22.25 kV）.The differences in the mean IQF of DR images at different tube voltages was significant （F=13.78,P〈0.001）.The IQF of DR imaging at 120 kV was similar to high kilovolt analog imaging （t=-0.58,P〉0.05）.In the anatomic phantom and clinical cases,the DR images at 120 kV were closest in anatomical detail to the high W analog images,and the means were similar （P〉0.05）.Conclusions Among different tube voltages,DR image quality is closest to the high kilovolt analog images at 120 kV in patients exposed to occupational dust.     

Extended operation for thoracic malignancies invading superior vena cava and/or innominate vein

Patients with thoracic malignancies invading the superior vena cava （SVC） and innominate vein that cause venous flow obstruction have a poor quality of lite and short survival time. Dartevelle et al reported that the 3-year survival rates were 27% for patients with mediastinal malignancies and non-small cell lung cancer. Recently, some surgeons＇ experience suggested that the results of extensive resection and reconstruction of the SVC and innominate vein were excellent. From May 2003 to December 2005, radical resection and reconstruction of the SVC and/or innominate vein were performed in a group of patients for mediastinal or lung tumors invading the superior vena cava and/or innominate vein. We reported our experience in this retrospective study to explore the operative method, the optimal vascular graft, and the benefits of extended resection and reconstruction of SVC and/or innominate vein for invasive thoracic tumors.     

Arthroscopy-assisted reconstruction of acute “floating popliteus tendon injury” in a mutiple-ligament knee injury

We describe a patient with both a femoral attachment injury(peel-off injury) and musculotendinous junction avulsion of the popliteus, a so-called “floating popliteus tendon injury”, treated with arthroscopy-assisted popliteus reconstruction. The injured ligaments were addressed in the same procedure, which included the following: mini-open direct repair of the femoral avulsed fibular collateral ligament(FCL), suture repair of the grade 3 medial collateral ligament(MCL), and reconstruction of the posterior cruciate ligament(PCL).     

Magnetic resonance imaging of eosinophilic meningoencephalitis caused by Angiostrongylus cantonensis following eating freshwater snails

Background Angiostrongyliasis cantonensis is a worldwide-existing parasitic disease. However, the relevant reports on its radiological appearances are limited. In this study, we investigated magnetic resonance imaging （MRI） features of eosinophilic meningoencephalitis in a group of consecutive patients caused by human infection with Angiostrongylus cantonensis after eating freshwater snails. Methods We performed brain MR imaging on 74 patients with angiostrongyliasis cantonensis. The scanner was a 0.5T unit. For each patient MR pulse sequences of $E Tl-weighted image （TlWl） and FSE T2-weighted image （T2Wl） were used. After intravenous administration of gadolinium chelate （Gd-DTPA） repeated Tl-weighted images were obtained. MRI features of the lesions in the brain and meninges were analyzed and recorded after observing initial and follow-up MR images. The classification of the types of angiostrongyliasis cantonensis infection was done on the basis of locations of the disorders. Results Forty-one （55%） normal and 33 （45%） abnormal MRI appearances in the brain were found. According to locations of the disorders, the types of angiostrongyliasis cantonensis infection were determined as follows： seventeen cases of type meningitis, three of type myeloencephalitis, one of type neuritis and twelve of mixed type （eight of type ventriculitis and five of type pneumonitis were among them）. In type meningitis, abnormal leptomeningeal enhancement was visualized. In type myeloencephalitis, lesions in the brain parenchyma may have iso- or slightly low signal intensity on TlWl and high signal intensity on T2Wl. Enhanced nodules in various shapes were shown on gadolinium-enhanced TlWl, a few lesions appeared as crescent enhancements and some lesions did not reveal abnormal enhancement. Other than brain lesions, an enhanced nodule was seen in the cervical spinal cord in one patient. In type ventriculitis, brain ventricular enlargement was demonstrated. In type neuritis, a nodule and abnormal enhancement     

Benefits of Mindfulness Training on the Mental Health of Women During Pregnancy and Early Motherhood: A Randomized Controlled Trial

Objective This study aimed to evaluate the effects of a mindfulness-based psychosomatic intervention on depression, anxiety, fear of childbirth(FOC), and life satisfaction of pregnant women in China.Methods Women experiencing first-time pregnancy(n = 104) were randomly allocated to the intervention group or a parallel active control group. We collected data at baseline(T0), postintervention(T1), 3 days after delivery(T2), and 42 days after delivery(T3). The participants completed questionnaires ...     

Imaging Techniques of Electrical Impedance Tomography for Real-time Medical Monitoring

Electrical Impedance Tomography （EIT） is a new functional imaging technique. To monitor the development of the internal hemorrhage which can not be continuously detected by presented clinical imaging methods, the imaging techniques of EIT are proposed for the continuous monitoring. The individual image mapping technique and consecutive images displaying technique were both used. Internal bleeding within human body was simulated by the drinking of 0.3% saline water and was measured continuously by EIT over a long period of time. A sequence of EIT images were generated at a rate of one image per second. It was found that the variations of the amounts of the saline water drunk could be shown by the consecutive images of EIT. Therefore, the imaging techniques are useful to facilitate EIT to become a promising bedside monitoring tool for the patients suffering from the active ongoing bleeding.     

Multi-slice CT angiography by triple-phase enhancement in preoperative evaluation of hepatocellular carcinoma

Background Triple-phase enhancement of multi-slice computed tomy (MSCT) has markedly improved the diagnostic accuracy of hepatocellular carcinoma (HCC), and MSCT angiography (MSCTA) has been proved useful in detecting vascular anatomy noninvasively. This study aimed to explore the value of MSCTA by triplephase enhancement in preoperative evaluation of HCC. Methods Fifty-six consecutive cases of primary HCC scheduled for resection were studied with MSCTA by triple-phase enhancement. The raw data images were processed on a workstation for multiplanar reconstruction (MPR) and three-dimensional (3D) reconstruction. The findings after processing of the data were compared with those after surgery or intraoperative sonography. Results The false positive rate of MSCTA by triple-phase enhancement was 10.1% and its false negative rate was 4.3% in detecting HCC. No significant difference was observed in MSCTA and surgery or intraoperative sonography in detecting vascular anatomy anomalies and pathologic variations, whereas significant difference was found in detecting bile duct invasion with MSCT compared to intraoperative sonography. Conclusions MSCTA by triple-phase enhancement not only improves the detection of HCC, but also provides valuable preoperative information about hepatic vascular architecture and parenehyma. MSCTA by triple-phase enhancement is worthy of application as a non-invasive method in preoperative evaluation of HCC.     

Value of preoperative magnetic resonance imaging measurements in thoracic percutaneous vertebroplasty using unilateral

Background Increasing the successful puncture rate of the percutaneous vertebroplasty （PVP） in thoracic vertebral compression fracture by unilateral puncture is a problem that spinal surgeons are trying to solve. The aim of this study was to assess the value of preoperative MRI imaging measurements for PVP using a unilateral puncture.Methods We performed a retrospective, comparative study of two groups of osteoporotic thoracic vertebral compression fracture patients who had received a PVP using a unilateral puncture. Group A （22 patients with 27 valid vertebrae） received PVP with a unilateral puncture between October 2005 and February 2007. Group B （18 patients with 24 valid vertebrae） received a routine MRI imaging measurements before a PVP between March 2007 and June 2008.We determined the target area to puncture based on the preoperative MRI cross-sectional images of vertebra. The PVP used a simultaneous puncture through a unilateral posterolateral approach, so the vertical distance from the point of skin puncture to the posterior median line, as well as the puncture angle, were measured using the MRI. The results were used to guide the PVP operation. We compared these two groups based on the average time for a single vertebra operation, the achievement ratio of puncture, and the incidence of bone cement leakage during surgery. The mean follow-up period was 14.2 months （range 12-23 months）. The pre- and post-operative visual analogue score （VAS） （3and 12 months post-surgery）, the variation of Oswestry disability index （ODI） and the incidence of long-term complications were also compared.Results The average time of a single vertebra operation in groups A and B were （34.7±5.4） and （23.3±4.2） minutes,respectively. In groups A and B, the success rates of puncture were 74.1% and 91.7%, respectively. Postoperative reduction of the average VAS scores in groups A and B at 3 and 12 months post-surgery were 5.8±2.1, 6.1±1.8, 6.1 ±2.0,6.2±1.6, respectively. However, the ODI increase was 41.6%±5.7%, 40.6%±6.0%, 46.3%±5.2%, 46.1%±6.7%. Paired t test evaluation of the values above showed a significant difference in the time of single-vertebra operation and the success rates between groups A and B （P 〈0.05）, but no significant difference was seen in the reduction of VAS scores and ODI （P 〉0.05）. There was no statistically significant difference in the complication rate between the two groups.Conclusions A preoperative MRI measurement effectively reduced the time of PVP with a unilateral puncture, which improved the success rate of the puncture without an additional risk of operation related complication.     

Anterior and middle skull base reconstruction after tumor resection

Background  Surgical management of skull base tumors is still challenging today due to its sophisticated operation procedure. Surgeons who specialize in skull base surgery are making endeavor to promote the outcome of patients with skull base tumor. A reliable skull base reconstruction after tumor resection is of paramount importance in avoiding life-threatening complications, such as cerebrospinal fluid leakage and intracranial infection. This study aimed at investigating the indication, operation approach and operation technique of anterior and middle skull base reconstruction.
Methods  A retrospective analysis was carried out on 44 patients who underwent anterior and middle skull base reconstruction in the Department of Neurosurgery at Beijing Tiantan Hospital between March 2005 and March 2008. Different surgical approaches were selected according to the different regions involved by the tumor. Microsurgery was carried out for tumor resection and combined endoscopic surgery was performed in some cases. According to the different locations and sizes of various defects after tumor resection, an individualized skull base soft tissue reconstruction was carried out for each case with artificial materials, pedicled flaps, free autologous tissue, and free vascularized muscle flaps, separately. A skull base bone reconstruction was carried out in some cases simultaneously.
Results  Soft tissue reconstruction was performed in all 44 cases with a fascia lata repair in 9 cases, a free vascularized muscle flap in 1 case, a pedicled muscle flap in 14 cases, and a pedicled periosteal flap in 20 cases. Skull base bone reconstruction was performed on 10 cases simultaneously. The materials for bone reconstruction included titanium mesh, free autogenous bone, and a Medpor implant. The result of skull base reconstruction was satisfactory in all patients. Postoperative early-stage complications occurred in 10 cases with full recovery after conventional treatment.
Conclusions  The specific characteristics of skull base defects in various regions require different reconstruction materials and methods. The individualized reconstruction based on different skull base defects can achieve satisfactory results.

     

EFFECTS OF INTERLEUKIN-4 ON GRANULOCYTE-MACROPHAGE-COLONY FORMATION FROM MURINE BONE MARROW CELLS AND HEMATOPOIETIC RECONSTITUTION FOLLOWING MURINE ALLOGENEIC BONE MARROW TRANSPLANTATION

We investigated the effects of mouse recombinant IL-4 on hematopoiesis in vitro and in vivo.IL-4 alone was found to be incapable of stimulating colony formation,but it inhibited both IL-3-and GM-CSF-induced colony for-mation by murine hematopoietic progenitor cells.In contrast,colony formation induced by G-CSF was enhanced in the presence of IL-4.We also studied the influence of IL-4 on hematopoietie reconstiution after allogeneic bone marrow transplantation in a murine model,and found that IL-4 and G-CSF was significantly suppressed by IL-4.The combination of IL-4 and GM-CSF caused a significant decrease in the absolute mumber of meutrophils.     

Medial plica after reconstruction of anterior cruciate ligament

Background The medial plica may be caused by direct trauma or joint degeneration, which also could be iatrogenic. There have been few reports in the literature discussing incidence of the medial plica caused by an operation on the knee joint, specifically after the reconstruction of anterior cruciate ligament （ACL）. In this study, we aimed to evaluate and analyze the relationship between the incidence of the medial plica and reconstruction of the ACL. Methods A retrospective case series study was conducted to review the findings of 1085 patients between 2003 and 2007, who underwent second-look arthroscopy after reconstruction of the ACL （between 2002 and 2006）. The correlation of the incidence of medial plica with the stability of the knee joint, the time from onset of injury to reconstruction surgery, the associated injuries, and the rate of progress during postoperative rehabilitation were analyzed. Results We found that 722 patients had the structure of a medial plica. The incidence after reconstruction of the anterior cruciate ligament （66.5%） was significantly higher than usually reported. All these medial plica had avascular fibrotic and thickened edges. An excision of pathologic medial plica and fat pad synovial fringes were done. The incidences were significantly different between the two groups with their reconstruction operation time, from onset of injury to surgery （less than one month or over 2 years）, and the progress rate of postoperative rehabilitation （knee flexion could not be over 90~ in four weeks）. The incidence was not different between the groups with knee stable conditions.
Conclusions Medial plica is more common in patients after reconstruction of ACL. More associated injuries and more rehabilitation difficulties can increase the medial plica incidence.     

A comparative study of calcium sulfate artificial bone graft versus allograft in the reconstruction of bone defect after tumor curettage

Background Cavity reconstruction after benign bone tumor removal is varied and controversial.AIIograft is widely used but is associated with complications.New bone substitutes,such as calcium sulfate artificial bone,have been introduced for bone tumor operation.However,the bone healing response of artificial bone has not been compared with allograft bone.We therefore compared calcium sulfate grafts （study group） with bone allografts （control group） for the treatment of benign bone tumors.Methods We retrospectively reviewed 50 patients who underwent calcium sulfate reconstruction and 50 patients who underwent allograft cancellous bone reconstruction.The two groups were well matched.The mean follow-up time of the study group was 19.9 （12-55） months.We investigated bone healing response,complications,and factors affecting bone healing.Results At the last follow-up,84％ （42/50） of cases in the study group and 62％ （31/50） of cases in the control group had achieved clinical healing （P=0.013）.The initial healing rate showed no significant difference between the two groups （100％ vs.96％,P=0.153）.The mean healing times for calcium sulfate and allograft bone were 9.6 （3-42） months and 13.8 （3-36） months,respectively （P ＜0.01）.Complications in the study group were minor and resolved.Implant volume was a significant factor affecting bone healing.Conclusion The calcium sulfate bone substitute showed a satisfactory healing outcome and safety profile in reconstruction of bone defects after benign bone tumor curettage,especially in smaller cavities.