Efficacy of multi-slice computed tomography cholangiography before laparoscopic cholecystectomy

BACKGROUND: Bile duct injury is one of the serious surgical complications of laparoscopic cholecystectomy (LC). Clear biliary tract imaging to detect the anomaly of the bile ducts before operation is thought to be useful to prevent this complication. The objective of this study was to investigate the preoperative feasibility of using multi-slice computed tomography scanning after drip infusion cholangiography-computed tomography (DIC-CT) for LC. METHODS: Laparoscopic cholecystectomies were carried out in 33 patients and DIC-CT and magnetic resonance cholangiography (MRC) were also carried out in all of these patients. We evaluated the recognition of the junction of the cystic duct and detection of anomalies of the extrahepatic bile ducts using the latter two methods. RESULTS: In 33 patients, DIC-CT showed the junction of the cystic duct in 31 (94%) and MRC in 25 (76%) patients, respectively. Anomalies of the extrahepatic bile ducts or the cystic duct were detected in four (12%) patients by DIC-CT, but MRC could show only one of these lesions. There were no major adverse reactions in either examination. CONCLUSION: DIC-CT is an efficacious preoperative technique as compared with MRC for the biliary tract imaging. DIC-CT may be of benefit for both patients scheduled to undergo LC and their surgeons.     

Quantification of regional variations in glenoid trabecular bone architecture and mineralization using clinical computed tomography images

The purpose of this study was to demonstrate feasibility of a clinical CT imaging and analysis technique to quantify regional variations in trabecular bone architecture and mineralization of glenoid bones. Specifically, our objective was to determine to what extent clinical CT imaging of intact upper extremities can describe variations of trabecular bone architectures at anatomic and peri‐implant regions by comparing trabecular bone architectures as measured by high‐resolution, micro CT imaging of same excised glenoid bones. Bone volume fraction (BVF), trabecular bone thickness (TbTh), number of trabecular bone (TbN), spacing (TbS), pattern factor (TbPf), bone surface area (BSA), and skeletal connectivity (Conn.), in addition to bone mineral content (BMC) and bone mineral density (BMD), were quantified from both clinical and micro CT images using whole bone, anatomic, and peri‐implant bone masks. Strong correlations of BVF, TbTh, TbSp, BMC, and BMD were found between clinical CT and micro CT imaging methods. The variations in BVF, TbTh, TbSp, TbN, BMC, and BMD at anatomical and peri‐implant regions were larger than those at whole bone regions. In this study, we have demonstrated that this clinical CT imaging methodology can be used to quantify variations of a patient's glenoid bone at anatomic and peri‐implant levels. Statement of Clinical Significance. An in vivo quantitative assessment of glenoid trabecular bone architecture in the anatomic and peri‐implant regions may improve our understanding on the role of bone quality on glenoid component loosening following total shoulder arthroplasty. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:85–96, 2018.     

Patient‐specific in silico models can quantify primary implant stability in elderly human bone

Secure implant fixation is challenging in osteoporotic bone. Due to the high variability in inter‐ and intra‐patient bone quality, ex vivo mechanical testing of implants in bone is very material‐ and time‐consuming. Alternatively, in silico models could substantially reduce costs and speed up the design of novel implants if they had the capability to capture the intricate bone microstructure. Therefore, the aim of this study was to validate a micro‐finite element model of a multi‐screw fracture fixation system. Eight human cadaveric humerii were scanned using micro‐CT and mechanically tested to quantify bone stiffness. Osteotomy and fracture fixation were performed, followed by mechanical testing to quantify displacements at 12 different locations on the instrumented bone. For each experimental case, a micro‐finite element model was created. From the micro‐finite element analyses of the intact model, the patient‐specific bone tissue modulus was determined such that the simulated apparent stiffness matched the measured stiffness of the intact bone. Similarly, the tissue modulus of a small damage region around each screw was determined for the instrumented bone. For validation, all in silico models were rerun using averaged material properties, resulting in an average coefficient of determination of 0.89 ± 0.04 with a slope of 0.93 ± 0.19 and a mean absolute error of 43 ± 10 μm when correlating in silico marker displacements with the ex vivo test. In conclusion, we validated a patient‐specific computer model of an entire organ bone‐implant system at the tissue‐level at high resolution with excellent overall accuracy. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:954–962, 2018.

     

Changes of density distribution of the subchondral bone plate after supramalleolar osteotomy for valgus ankle osteoarthritis

CT‐osteoabsorptiometry (CT‐OAM) has been used to visualize subchondral bone plate density distribution regarding to its mineralization. The purpose of this study was to display and analyze the density distribution of the subchondral bone plate before and after supramalleolar realignment osteotomies. We retrospectively analysed pre‐ and postoperative CT images of nine consecutive patients with post‐traumatic unilateral valgus ankle OA. The distribution charts of CT‐OAM scans were quantitatively analyzed for subchondral bone plate density distribution. VAS for pain and the Tegner activity scale were used to assess clinical outcome. At a mean follow‐up of 20 ± 5.6 months (range 13–27), we observed a significant pre‐ to postoperative decrease of the mean high‐density area ratio in tibia (lateral and posterior area) (p ≤ 0.05) and the talus (lateral area) (p ≤ 0.05). Pairwise comparison between the pre‐ and postoperative mineralization at the articular surface showed a significant decrease of the high‐density area ratio for the tibia and the talus. The VAS decreased from 6.2 ± 0.9 pre‐ to 2.8 ± 0.9 postoperatively (p = 0.027), and the Tegner score inclined from 4.5 ± 1.1 preoperatively to 5.3 ± 0.7 after surgery (p = 0.082). The tibial and talar subchondral bone plate density, regarding to its mineralization, decreased after supramalleolar medial closing wedge osteotomy in patients with valgus ankle OA. The results of this study suggest that realignment surgery may decrease peak bone density areas corresponding to the alignment correction and contribute to a homogenization of the subchondral bone plate mineralization. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1356–1361, 2014. Level of evidence Level IV, Case series.     

A Pilot Study Evaluating Shaved Cavity Margins with Micro‐Computed Tomography: A Novel Method for Predicting Lumpectomy Margin Status Intraoperatively

Microscopically clear lumpectomy margins are essential in breast conservation, as involved margins increase local recurrence. Currently, 18–50% of lumpectomies have close or positive margins that require re‐excision. We assessed the ability of micro‐computed tomography (micro‐CT) to evaluate lumpectomy shaved cavity margins (SCM) intraoperatively to determine if this technology could rapidly identify margin involvement by tumor and reduce re‐excision rates. Twenty‐five SCM from six lumpectomies were evaluated with a Skyscan 1173 table top micro‐CT scanner (Skyscan, Belgium). Micro‐CT results were compared to histopathological results. We scanned three SCM at once with a 7‐minute scanning protocol, and studied a total of 25 SCM from six lumpectomies. Images of the SCM were evaluated for radiographic signs of breast cancer including clustered microcalcifications and spiculated masses. SCM were negative by micro‐CT in 19/25 (76%) and negative (≥2 mm) by histopathology in 19/25 (76%). Margin status by micro‐CT was concordant with histopathology in 23/25 (92%). Micro‐CT overestimated margin involvement in 1/25 and underestimated margin involvement in 1/25. Micro‐CT had an 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for evaluation of SCM. Evaluation of SCM by micro‐CT is an accurate and promising method of intraoperative margin assessment in breast cancer patients. The scanning time required is short enough to permit real‐time feedback to the operating surgeon, allowing immediate directed re‐excision.     

Microcomputed tomography imaging in a rat model of delayed union/non‐union fracture

We aimed to develop a clinically relevant delayed union/non‐union fracture model to evaluate a cell therapy intervention repair strategy. Histology, three‐dimensional (3D) microcomputed tomography (micro‐CT) imaging and mechanical testing were utilized to develop an analytical protocol for qualitative and quantitative assessment of fracture repair. An open femoral diaphyseal osteotomy, combined with periosteal diathermy and endosteal excision, was held in compression by a four pin unilateral external fixator. Three delayed union/non‐union fracture groups established at 6 weeks—(a) a control group, (b) a cell therapy group, and (c) a group receiving phosphate‐buffered saline (PBS) injection alone—were examined subsequently at 8 and 14 weeks. The histological response was combined fibrous and cartilaginous non‐unions in groups A and B with fibrous non‐unions in group C. Mineralized callus volume/total volume percentage showed no statistically significant differences between groups. Endosteal calcified tissue volume/endosteal tissue volume, at the center of the fracture site, displayed statistically significant differences between 8 and 14 weeks for cell and PBS intervention groups but not for the control group. The percentage load to failure was significantly lower in the control and cell treatment groups than in the PBS alone group. High‐resolution micro‐CT imaging provides a powerful tool to augment characterization of repair in delayed union/non‐union fractures together with outcomes such as histology and mechanical strength measurement. Accurate, nondestructive, 3D identification of mineralization progression in repairing fractures is enabled in the presence or absence of intervention strategies. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:729–736, 2008     

Three‐dimensional CT cavernosography: reconsidering venous ligation surgery on the basis of the modern technology

Study Type – Therapy (case series)
Level of Evidence 4 What’s known on the subject? and What does the study add? Venous ligation surgery has been conducted as a symptomatic treatment, but the effective rate of this surgery was insufficient. We thought that one of the reasons for the low effective rate of this surgery was insufficient for the diagnostic modality. We confirmed that 3D cavernosography was, in comparison with conventional cavernosography, higher in diagnosis precision.

OBJECTIVE

• ? To examine the feasibility of three‐dimensional (3D) CT cavernosography in the diagnosis of corporal veno‐occlusive dysfunction.

PATIENTS AND METHODS

• ? The subjects were 55 patients who had failed to respond to phosphodiesterase type 5 inhibitors. We performed pharmacodynamic infusion cavernosometry and cavernosography, using 60 mg papaverine hydrochloride.
• ? Cavernosography was performed at 90 mmHg intracavernous pressure, using a multi‐slice CT scan system. The 3D images were reconstructed using aquarius net station , ver.2 computer software.
• ? For comparison with conventional cavernosography, maximum intensity projection (MIP) images were used. A flow of 20 mL/min or being more capable of maintaining 90 mmHg of intracavernous pressure indicated veno‐occlusive dysfunction.

RESULTS

• ? Forty‐five of the 55 patients were diagnosed with corporal veno‐occlusive dysfunction. 3D‐CT cavernosography revealed drainage veins in all 45 cases, including cavernous veins, dorsal veins, crural veins and other emissary veins.
• ? Compared with 3D‐CT cavernosography, observing cavernous veins and the proximal part of the deep dorsal veins using MIP imaging was especially difficult because the origins of the penile veins are often behind the pelvic bone or cavernous body.
• ? Of the patients who seemingly had leakage via the deep dorsal vein, 80.6% did not in fact have leakage via this vein, but had other leakages. The image resolution of 3D‐CT cavernosography was significantly higher than that of MIP.

CONCLUSION

• ? 3D‐CT cavernosography can provide high‐resolution images of venous drainage from any angle. We conclude that the images obtained by 3D‐CT cavernosography are very helpful for both the diagnosis of corporal veno‐occlusive dysfunction and the anatomical study of the human penile venous system.

     

Effects of vibration treatment on tibial bone of ovariectomized rats analyzed by in vivo micro‐CT

Daily low‐amplitude, high‐frequency whole‐body vibration (WBV) treatment can increase bone formation rates and bone volume in rodents. Its effects vary, however, with vibration characteristics and study design, and effects on 3D bone microstructure of ovariectomized animals over time have not been documented. Our goal was to determine the effects of WBV on tibial bone of ovariectomized, mature rats over time using an in vivo micro‐CT scanner. Adult rats were divided into: ovariectomy (OVX) (n = 8), SHAM‐OVX (n = 8), OVX and WBV treatment (n = 7). Eight weeks after OVX, rats in the vibration group were placed on a vibrating platform for 20 min at 0.3 g and 90 Hertz. This was done 5 days a week for six weeks, twice a day. Zero, 8, 10, 12 and 14 weeks after OVX, in vivo micro‐CT scans were made (vivaCT 40, Scanco Medical AG) of the proximal and diaphyseal tibia. After sacrifice, all tibiae were dissected and tested in three‐point bending. In the metaphysis between 8 to 12 weeks after OVX, WBV treatment did not alter structural parameters compared to the OVX group and both groups continued to show deterioration of bone structure. In the epiphysis, structural parameters were not altered. WBV also did not affect cortical bone and its bending properties. To summarize, no substantial effects of 6 weeks of low‐magnitude, high‐frequency vibration treatment on tibial bone microstructure and strength in ovariectomized rats were found. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:62–69, 2010     

Prospects in radionuclide imaging of prostate cancer

Prostate cancer is the most common malignancy in men in the Western world and represents a major health problem with substantial morbidity and mortality. Sensitivity and specificity of digital rectal examination (DRE) and evaluation of prostate specific antigen (PSA) are excellent methods for diagnosis of prostate cancer, but have limited value for staging. Imaging of prostate cancer has become increasingly important to improve staging and management of prostate cancer patients. Conventional imaging modalities, such as transrectal ultrasound and computed tomography, show limited accuracy for a reliable assessment of prostate cancer. Diagnostic value of magnetic resonance imaging has improved by dynamic contrast enhancement (DCI-MRI) and diffusion-weighted magnetic resonance imaging (DWI). Recently, substantial progress has been made in the development of functional and molecular imaging modalities, such as positron emission tomography using radiolabeled metabolic tracers, receptor-binding ligands, amino acids, peptides, or antibodies. Here, we review the value of these novel radionuclide imaging techniques in the assessment of prostate cancer.