Multidetector-row Computed Tomography Research Articles

CT Foot Perfusion Examination for Evaluation of Percutaneous Transluminal Angioplasty Outcome in Patients with Critical Limb Ischemia: A Feasibility Study

PurposeTo evaluate foot perfusion in patients with critical limb ischemia (CLI) using quantitative perfusion multi–detector-row CT and estimate perfusion parameter changes before and after percutaneous transluminal angioplasty (PTA). Materials and MethodsThis prospective study investigated 13 patients (10 men; median age, 72 y; range, 51–84 y) with CLI who underwent CT foot perfusion examinations with a 128-slice dual-energy CT scanner 1 day before and 1 week after PTA. Key parameters such as permeability surface (PS), blood volume (BV), and blood flow (BF) were analyzed and compared statistically. The studies were also examined by a second observer to determine interobserver reproducibility. ResultsRevascularization was technically successful in all patients, and mean ankle–brachial index increased from 0.36 ± 0.16 to 0.75 ± 0.22. After revascularization, mean BV increased from 1.55 mL/100 g ± 0.83 to 4.51 mL/100 g ± 1.53, BF increased from 16.28 mL/100 g/min ± 4.97 to 31.49 mL/100 g/min ± 6.86, and PS increased from 3.1 mL/min/100 g ± 1.95 to 8.67 mL/min/100 g ± 3.85 (P < .05). Patients with poor response to revascularization who finally underwent amputation presented lower post-PTA perfusion parameters values than patients with significant clinical improvement (P < .05). All measurements demonstrated very good interobserver reproducibility, and intraclass correlation coefficients were 0.91 for BV, 0.94 for BF, and 0.95 for PS. The mean effective dose of the examination was estimated at 0.29 mSv. ConclusionsCT foot perfusion is a reproducible technique that may be a useful modality for the estimation of PTA outcome. Significant restitution of perfusion parameters was observed after successful revascularization.

Prognostic factors for maxillary sinus mucosal thickening following Le Fort I osteotomy: a retrospective analysis

BackgroundLe Fort I osteotomy is one of the surgical procedures now routinely and safely performed. It is possible to move the maxilla in three dimensions, but it is necessary to separate the bones around the maxillary sinus. Therefore, with surgery, maxillary sinus mucosal thickening occurs. By knowing the changes in the sinus mucosa after surgery and the factors affecting it, it is possible to better predict the outcomes of surgery and contribute to safer surgery. In this study, thickening of maxillary sinus mucosa before and after surgery in Le Fort I osteotomy was evaluated using multidetector-row computed tomography (MDCT) images, and the changes in mucosal thickening and the related factors were examined.MethodsUsing MDCT images, the maxillary sinus mucosa of 125 patients who had undergone Le Fort I osteotomy was retrospectively evaluated before surgery, 1 month after surgery, and 1 year after surgery. On the MDCT images, the maxillary sinus was judged as mucosal thickening and classified into three grades according to the proportion occupying the maxillary sinus. In the evaluation of factors related to mucosal thickening, the following eight factors were examined: sex, age, diagnosis, operating time, amount of postoperative bleeding, with/without bone graft, with/without multisegmental osteotomy, and with/without macrolide therapy after surgery.ResultsThe mean age at the time of surgery was 25.6 ± 8 years. Of all 125 patients, 66 had bilateral thickening, 19 had unilateral thickening, and 40 had no thickening. Factors that were significantly related to mucosal thickening were the operative time for the maxilla, bone grafts, and macrolide therapy after surgery.ConclusionsOperative time for the maxilla, bone grafts, and macrolide therapy after surgery were found to be related to mucosal thickening. In addition, MDCT scanning 1 month after surgery was considered to be appropriate for evaluation of maxillary sinus mucosal thickening.

Diagnostic abilities of 3T MRI for assessing mandibular invasion of squamous cell carcinoma in the oral cavity: comparison with 64-row multidetector CT.

To evaluate the diagnostic accuracies of 3T MRI in evaluating mandibular invasion of squamous cell carcinoma (SCC) in the oral cavity and to compare those with that of multidetector CT (MDCT). 41 cases with oral SCC examined by both 3T MRI and MDCT prior to surgery were included in this study. Intravenous contrast medium was administered in all examinations. Images were evaluated for the presence or absence of mandibular invasion and mandibular canal involvement by the tumour. For MRI, both two-dimensional (2D) fast spin echo (FSE) and three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) images were used for the evaluation. For MDCT, dental CT cross-sectional images were rused. The results were correlated with histopathological findings, and sensitivity and specificity of each imaging technique were calculated.DMFR prrof. Histopathologically, 32 of 41 cases had mandibular invasion and 10 cases had mandibular canal involvement. For mandibular invasion, all three imaging techniques showed sensitivities of 100%. However, the specificities of 2D FSE (56%) and 3D VIBE (78%) were lower than that of MDCT (89%), although the differences were not significant. For mandibular canal involvement, whereas the sensitivities of all three imaging techniques were 100%, the specificities of 2D FSE, 3D VIBE and MDCT were 54, 62 and 85%, respectively. The specificity of 2D FSE was significantlylower than that of MDCT (P < 0.017). In the evaluation of mandibular invasion, 3T MRI was not as accurate as MDCT. In particular, 2D FSE sequences showed significantly lower specificity than MDCT in evaluating the extent of mandibular invasion. The use of 3D VIBE sequence slightly improved the low specificity of 2D FSE sequences.

Optimal diagnostic method using multidetector-row computed tomography for predicting lymph node metastasis in colorectal cancer

BackgroundPrediction of nodal involvement in colorectal cancer is an important aspect of preoperative workup to determine the necessity of preoperative treatment and the adequate extent of lymphadenectomy during surgery. This study aimed to investigate newer multidetector-row computed tomography (MDCT) findings for better predicting lymph node (LN) metastasis in colorectal cancer.MethodsSeventy patients were enrolled in this study; all underwent MDCT prior to surgery and upfront curative resection for colorectal cancer. LNs with a short-axis diameter (SAD) ≥ 4 mm were identified on MDCT images, and the following measures were recorded by two radiologists independently: two-dimensional (2D) SAD, 2D long-axis diameter (LAD), 2D ratio of SAD to LAD, 2D CT attenuation value, three-dimensional (3D) SAD, 3D LAD, 3D SAD to LAD ratio, 3D CT attenuation value, LN volume, and presence of extranodal neoplastic spread (ENS), as defined by indistinct nodal margin, irregular capsular enhancement, or infiltration into adjacent structures.ResultsForty-six patients presented 173 LNs with a SAD ≥ 4 mm, while 24 patients exhibited pathologically confirmed LN metastases. Receiver operating characteristic analysis revealed that 2D LAD was the most sensitive measure for LN metastases with an area under the curve of 0.752 (cut-off value, 7.05 mm). When combined with CT findings indicating ENS, 2D LAD (> or ≤ 7 mm) showed enhanced predictive power for LN metastases (area under the curve, 0.846; p < 0.001).ConclusionsLAD in axial MDCT imaging is the most sensitive measure for predicting colorectal LN metastases, especially when MDCT findings of ENS are observed.

Usefulness of non-contrast MR imaging in distinguishing pancreatic ductal adenocarcinoma from focal pancreatitis

BackgroundAccurate differentiation between pancreatic adenocarcinoma and focal pancreatitis is challenging. PurposeTo investigate the usefulness of non-contrast MRI by comparing with multidetector row CT (MDCT) and gadoxetic acid-enhanced MRI in the discrimination of pancreatic ductal adenocarcinoma (PDAC) and focal pancreatitis (FP). Materials and methodsThis retrospective study included 187 patients (116 with PDACs and 71 with FP) who underwent gadoxetic acid-MRI and MDCT prior to surgical resection or biopsy. The MRI features of PDAC and FP were compared by two radiologists. Then, two observers independently reviewed the three imaging sets: MDCT, non-contrast MRI (T1-, T2-weighted, and diffusion-weighted images), and MRI with and without gadoxetic acid to determine the diagnostic performances of each imaging modality in the discrimination of PDAC and FP. ResultsThe significant features on non-contrast MRI for diagnosis of PDAC included peritumoral cyst, pancreatic duct cut-off, clear hypointensity on T1WI, and bile duct dilatation (P < 0.05). Presence of peritumoural cyst showed the highest odds ratio for predicting PDAC. Non-contrast MRI was superior to MDCT in differentiating PDAC from FP with regard to accuracy (84.5% vs 95.5% for observer 1; 85.8% vs. 96.0% for observer 2), sensitivity (83.6% vs. 98.3%; 84.5% vs 97.8%), and negative predictive value (76.3% vs. 97.0%; 77.6% vs 96.4%) (P < 0.05). We found similar diagnostic values between the non-contrast MRI and MRI with and without contrast (P > 0.05) for both observers. ConclusionNon-contrast MRI is better than MDCT and comparable to MRI with and without gadoxetic acid in differentiating PDAC from FP.

Diagnostic Value of Advanced Imaging Modalities for the Detection and Differentiation of Prosthetic Valve Obstruction: A Systematic Review and Meta-Analysis

ObjectivesThis meta-analysis investigated the diagnostic values of transthoracic echocardiography (TTE), 2-dimensional (2D) and 3-dimensional (3D) transesophageal echocardiography (TEE), and multidetector-row computed tomography (MDCT) in patients with suspected mechanical prosthetic valve obstruction (PVO) for detecting subprosthetic mass and differentiating its causes. BackgroundDiagnostic values of advanced imaging modalities, such as MDCT and TEE, for the detection and differentiation of PVO have not been investigated. MethodsPubMed and EMBASE were systematically searched for studies that evaluated PVO using imaging modalities. The modified Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to evaluate study quality. Pooled sensitivity of each modality for PVO detection and pooled diagnostic accuracy of TEE and MDCT for differentiating the causes of PVO were analyzed. Study heterogeneity was also assessed. ResultsSeventeen studies (229 patients) that used at least 1 index tool among TTE, TEE, or MDCT were included. For detecting a subprosthetic mass that caused PVO, 3D TEE and MDCT showed a higher sensitivity of 81% (95% confidence interval [CI]: 40% to 95%) and 88% (95% CI: 81% to 93%), respectively, compared with TTE (20%; 95% CI: 7% to 47%) and 2D TEE (68%; 95% CI: 46% to 84%). Pooled sensitivity and specificity for diagnosing thrombus as a cause of PVO was 75% (95% CI: 54% to 88%) and 75% (95% CI: 40% to 93%), respectively, for TEE and 45% (95% CI: 16% to 77%) and 90% (95% CI: 77% to 96%), respectively, for MDCT. Pooled sensitivity for diagnosing pannus as a cause of PVO was 62% (95% CI: 46% to 76%) for TEE and 85% (95% CI: 70% to 93%) for MDCT. ConclusionsThis meta-analysis suggested that MDCT and 3D TEE have higher sensitivity than do TTE and 2D TEE, and can be reliable imaging modalities for detecting a subprosthetic mass that causes PVO. Moreover, MDCT can more accurately differentiate the cause of PVO than does TEE.

A survey of pediatric CT doses in the Shanghai metropolitan area

The purpose of this study was to evaluate computed tomography (CT) doses in child examinees at different ages throughout the Shanghai metropolitan area. The head and body CT dose indices (CTDIs) of 50 CT scanners were tested by phantom measurements using standard imaging protocols. The values of CTDIw, CTDIvol and dose length product (DLP) were calculated and saved in a table along with the parameters of routine head and chest scans for different age groups of children and adults. The effective doses were estimated from the K-factors by age and DLP. The CTDIvol, DLP and effective dose for multi-detector row CT (MDCT) in children during routine head scans were larger than those for single-detector row CT (SDCT) and dual-detector row CT (DDCT). The CTDIvol, DLP and effective dose for MDCT and DDCT in children during routine chest scans were lower than those for SDCT. Radiation risks are higher for children in CT examinations compared to adults.

Basic analysis of facial ageing: The relationship between the superficial musculoaponeurotic system and age.

The superficial musculoaponeurotic system (SMAS) is an anatomical structure involved in the facial ageing process. We aimed to evaluate the SMAS laxity using multi-detector row computed tomography (MDCT) as a diagnostic tool, and to analyse the relationship between SMAS laxity and age. Fifty-seven female subjects (aged 21-57years) were enrolled in the study. The subjects were divided into two age groups: one below the mean age (Group Y, 30 subjects) and one over it (Group O, 27 subjects). The Posture Change (PC)-induced SMAS Laxity Index was measured using reconstructed CT images, and the relationship between the PC-induced SMAS Laxity Index and age was analysed. The PC-induced SMAS Laxity Index was significantly larger in Group O than in Group Y. As well, a strong and significant positive correlation was detected between the PC-induced SMAS Laxity Index and age (r=0.72; P<0.001). The use of MDCT provides insight into the detailed changes associated with ageing that take place within the cheeks. This study objectively demonstrated that SMAS laxity and age are factors associated with facial ageing, as the SMAS laxity increased with age. Finally, the imaging features confirmed the dermatological and aesthetic knowledge gained from plastic surgery regarding the loss of the SMAS supporting force due to facial ageing.

Preoperative T staging of colon cancer using CT colonography with multiplanar reconstruction: new diagnostic criteria based on "bordering vessels".

Preoperative T staging of colon cancer, in particular, for distinguishing T3 from T2 and T4, has been a challenge. The aim of this study was to evaluate newly developed criteria for preoperative T staging of colorectal cancer using computed tomography colonography (CTC) with multiplanar reconstruction (MPR), based on the spatial relationship of tumors and "bordering vessels," that is, marginal vessels that are detectable by multi-detector row CT with MPR. A total of 172 patients with colon and upper rectal cancer who underwent preoperative CTC and surgery between August 2011 and September 2013 were included. Preoperative T staging using the new criteria was performed prospectively and compared with pathologic results. Sensitivity, specificity, and accuracy of T staging by CTC using the new criteria were 63%, 80%, and 77% for T2 (n = 30); 72%, 94%, and 81% for T3 (n = 95); and 79%, 99%, and 97% for T4a (n = 14), respectively. Positive predictive value for T3 was 93%, indicating that a T3 diagnosis by CTC is precise. In addition, negative predictive value for pathological T4a was 98%, indicating that a "not T4a" diagnosis by CTC is also precise. Our newly developed criteria are useful for preoperative T staging, particularly for distinguishing T3 from T2 and T4.

Predictive Value of Preoperative Multidetector-Row Computed Tomography for Axillary Lymph Nodes Metastasis in Patients With Breast Cancer

Introduction: Axillary lymph nodes (ALN) status is an essential component in tumor staging and treatment planning for patients with breast cancer. The aim of present study was to evaluate the predictive value of preoperative multidetector-row computed tomography (MDCT) for ALN metastasis in breast cancer patients.Methods: A total of 148 cases underwent preoperative MDCT examination and ALN surgery were eligible for the study. Logistic regression analysis of MDCT variates was used to estimate independent predictive factors for ALN metastasis. The prediction of ALN metastasis was determined with MDCT variates through receiver operating characteristic (ROC) analysis.Results: Among the 148 cases, 61 (41.2%) cases had ALN metastasis. The cortical thickness in metastatic ALN was significantly thicker than that in non-metastatic ALN (7.5 ± 5.0 mm vs. 2.6 ± 2.8 mm, P < 0.001). Multi-logistic regression analysis indicated that cortical thickness of >3 mm (OR: 12.32, 95% CI: 4.50–33.75, P < 0.001) and non-fatty hilum (OR: 5.38, 95% CI: 1.51–19.19, P = 0.009) were independent predictors for ALN metastasis. The sensitivity, specificity and AUC of MDCT for ALN metastasis prediction based on combined-variated analysis were 85.3%, 87.4%, and 0.893 (95% CI: 0.832–0.938, P < 0.001), respectively.Conclusions: Cortical thickness (>3 mm) and non-fatty hilum of MDCT were independent predictors for ALN metastasis. MDCT is a potent imaging tool for predicting ALN metastasis in breast cancer. Future prospective study on the value of contrast enhanced MDCT in preoperative ALN evaluation is warranted.

Quantitative assessment and risk factors for chest wall deformity resulting from tissue expansion for breast reconstruction.

Chest wall deformity after tissue expansion for breast reconstruction is less recognized than complications such as infection, hematoma, skin necrosis and capsular contracture. However, the condition should not be discounted because pain, rib fracture and dyspnea may occur in severe cases. The aim of this study is to evaluate the extent of chest wall deformity quantitatively using computed tomography (CT) and to identify risk factors for this condition after tissue expansion. The subjects were 34 patients who underwent unilateral two-stage reconstruction and were examined by multidetector-row CT before expander surgery and during maximal tissue expansion. Chest wall deformity was assessed quantitatively using the Chest Wall Deformity Index (CWDI), which was measured before expander surgery (pre-CWDI) and during maximal tissue expansion (post-CWDI). Post minus pre (post-pre) CWDI was used as the index of chest wall deformity in the assessment of risk factors. Post-CWDI was significantly higher than pre-CWDI (3.66 ± 3.23% vs. 0.03 ± 2.74%, P < 0.001 by paired t test), showing that chest wall deformity occurred after maximum expansion. In a multiple linear regression model, capsular contracture emerged as a significant predictor of increased post-pre CWDI (P = 0.003). BMI was a significant predictor of decreased post-pre CWDI (P = 0.003), but this result may have been due to the measurement method. Our findings suggest that chest wall deformity is common after maximum tissue expansion for breast reconstruction. Awareness of the possibility of chest wall deformity during tissue expansion is important, particularly in cases with capsular contracture.

Predictors of Left Ventricular Outflow Tract Obstruction After Transcatheter Mitral Valve Replacement

ObjectivesThe aim of this study was to evaluate the predictors of left ventricular outflow tract (LVOT) obstruction after transcatheter mitral valve replacement (TMVR). BackgroundLVOT obstruction is a major concern with TMVR, but limited data exist regarding its predictors and impact on outcomes. MethodsPatients with pre-procedural multidetector row computed tomography (MDCT) undergoing TMVR for failed mitral bioprosthetic valves (valve-in-valve), annuloplasty rings (valve-in-ring), and mitral annular calcification (valve-in-MAC) were included in this study. Echocardiographic and procedural characteristics were recorded, and comprehensive assessment with MDCT was performed to identify the predictors of LVOT obstruction (defined as an increment of mean LVOT gradient ≥10 mm Hg from baseline). The new LVOT (neo-LVOT) area left after TMVR was estimated by embedding a virtual valve into the mitral annulus on MDCT, simulating the procedure. ResultsAmong 194 patients with pre-procedural MDCT undergoing TMVR (valve-in-valve, 107 patients; valve-in-ring, 50 patients; valve-in-MAC, 37 patients), LVOT obstruction was observed in 26 patients (13.4%), with a higher rate after valve-in-MAC than valve-in-ring and valve-in-valve (54.1% vs. 8.0% vs. 1.9%; p < 0.001). Patients with LVOT obstruction had significantly higher procedural mortality compared with those without LVOT obstruction (34.6% vs. 2.4%; p < 0.001). Receiver-operating characteristic curve analysis showed that an estimated neo-LVOT area ≤1.7 cm2 predicted LVOT obstruction with sensitivity of 96.2% and specificity of 92.3%. ConclusionsLVOT obstruction after TMVR was associated with higher procedural mortality. A small estimated neo-LVOT area was significantly associated with LVOT obstruction after TMVR and may help identify patients at high risk for LVOT obstruction.

Analysis of Dentoalveolar and Maxillofacial Fractures with Multidetector-Row Computed Tomography

Dentoalveolar trauma may occur after accidental falls, automotive accidents, violence, or contact sport injuries. This study aimed to investigate the prevalence of dentoalveolar and maxillofacial fractures with multidetector-row computed tomography (MDCT). Forty patients with dentoalveolar and maxillofacial fractures underwent MDCT. Mandibular fractures were classified into four types: median, paramedian, angle and condylar types. Midface fractures were classified into four types: Le Fort I-III and zygomatic maxillary complex types. Statistical analysis of the relationship between prevalence of dentoalveolar fractures and maxillofacial fracture locations was performed using Chi-square test with Fisher's exact test. A p-value less than 0.05 was considered statistically significant. The prevalence of dentoalveolar fractures was 15.0% (6/40 cases) of all patients with maxillofacial fractures. The mean age of patients with and without dentoalveolar fractures in maxillofacial fractures were 39.8 years and 54.7 years, respectively. Regarding cause of injury, the prevalence of maxillofacial fractures with dentoalveolar fractures were 18.8% of accidental falls and 0% of contact sport injuries and automotive accidents. There was no significant relationship between prevalence of dentoalveolar and maxillofacial fractures. The results suggest that the prevalence of dentoalveolar and maxillofacial fractures are related to the age and cause of injury.

Predictive values of multidetector-row computed tomography combined with serum tumor biomarkers in preoperative lymph node metastasis of gastric cancer.

ObjectiveMultidetector-row computed tomography (MDCT) and serum tumor biomarkers are commonly used to evaluate the preoperative lymph node metastasis and the clinical staging of gastric cancer (GC). This study intends to evaluate the clinical predictive value of MDCT and serum tumor biomarkers in lymph node metastasis of GC.MethodsThe clinicopathologic data of 445 GC patients who underwent radical gastrectomy were retrospectively analyzed to evaluate the diagnostic value of MDCT and serum tumor biomarkers in lymph node metastatic staging of GC before surgery.ResultsWith the multinomial logistic regression analysis, the independent relative factors of lymph node metastasis of GC were identified as tumor size, depth of tumor invasion, vessel invasion, vascular embolus, and soft tissue invasion. The optimal critical value of the short diameter of lymph nodes detected by MDCT scanning for evaluation of preoperative lymph node metastasis was 6.0 mm, with 75.7% as predictive accuracy of lymph node metastasis compared to the postoperative pathological results of GC patients. In addition, the critical value of the short diameter of lymph nodes combined with serum tumor biomarkers [including carbohydrate antigen (CA)-724 and CA-199] could show an enhancement of predictive sensitivity of lymph node metastasis (up to 89.3%) before surgery.ConclusionsMDCT combined with serum tumor biomarkers should be adopted to improve preoperative sensitivity and accuracy of lymph node metastasis for GC patients.

Recent fluorescence-based optical imaging for video-assisted thoracoscopic surgery segmentectomy.

The importance of fluorescence-based optical imaging in various fields of surgery is increasing. This is a prospective cohort study aimed to investigate the feasibility and efficacy of indocyanine-green fluorescence (ICGF)-based navigation for near-infrared (NIR) thoracoscopic segmentectomy. ICGF-based video-assisted thoracoscopic surgery (VATS) segmentectomy was performed in 149 patients. Each patient underwent preoperative evaluation by multidetector-row computed tomography (MDCT), which provided three-dimensional simulations of vascular structures, segmental bronchi, and lung tumor. During the procedure, low-dose ICG (0.25 mg/kg) was injected systemically after the target segmental pulmonary arteries and bronchus were divided. Under NIR-thoracoscopic guidance, an ICG fluorescent line was marked by electric scalpel, followed by division of lung parenchyma along the line by electric scalpel or endoscopic staples. An intersegmental line of ICGF was visible in 98% of patients, even with the use of low-dose ICG. Neither ICG-related adverse events nor procedure-related major complications occurred. The 5-year overall (OS) and recurrence-free survival (RFS) rates were 91.8% and 98%, respectively. Localized recurrence at the resected site did not occur in any patient. ICGF-based navigation for NIR VATS segmentectomy for patients with lung cancer is feasible and effective.

Novel classification for Right posterior portal vein (RPPV) evaluated by SYNAPSE VINCENT

Introduction: The debate on whether a CouinaudSegmentectomyis an anatomical resection or not is far from over. The reason for the question was that there was no in-deepedand detailed description of the patterns of the 2nd, 3rdportal branch.The present study is attempt to description the patterns of the 2nd, 3rdportal branch in right posterior portal vein. Method: Between November 2008 and Janury2017, the a total of 106 preoperative multidetector-row computed tomography (MDCT) images were obtained from the donors of adult living donor liver transplantation and the 3D images were reconstructed by SYNAPSE VINCENT medical imaging system. The patterns of the right posterior portal vein (RPPV) and the 2nd, 3rdportal branch of the RPPV the were investigated using SYNAPSE VINCENT medical imaging system. Result: After analysis the patterns of the right posterior portal vein (RPPV) and the 2nd, 3rdportal branch of the RPPV, we classified the RPPV into four types (Fig. 1). Type A: the RPPV have a common trunk (more than 5mm) with two main 3rdorder branch (36 cases, 34%); Type B: there was no common trunk with two main 2ndorder branch (16 cases, 15%); Type C: there was one major common trunk with multiple 3rdorder branch (48 cases, 45.3%); Type D: the right posterior section have sliding branches to/from anterior portal vein (6 cases, 5.7%). The median length of the type A portal trunk was 12.35mm (range 5.0mm-28.7mm). Conclusion: A deep and detailed description of the patterns of the 2nd, 3rd portal branch in RPSis helpful to find out the variation of RPS and keep the surgery safe.

Estimating a size-specific dose for helical head CT examinations using Monte Carlo simulation methods.

Size-specific dose estimates (SSDE) conversion factors have been determined by AAPM Report 204 to adjust CTDIvol to account for patient size but were limited to body CT examinations. The purpose of this work was to determine conversion factors that could be used for an SSDE for helical, head CT examinations for patients of different sizes. Validated Monte Carlo (MC) simulation methods were used to estimate dose to the center of the scan volume from a routine, helical head examination for a group of patient models representing a range of ages and sizes. Ten GSF/ICRP voxelized phantom models and five pediatric voxelized patient models created from CT image data were used in this study. CT scans were simulated using a Siemens multidetector row CT equivalent source model. Scan parameters were taken from the AAPM Routine Head protocols for a fixed tube current (FTC), helical protocol, and scan lengths were adapted to the anatomy of each patient model. MC simulations were performed using mesh tallies to produce voxelized dose distributions for the entire scan volume of each model. Three tally regions were investigated: (1) a small 0.6cc volume at the center of the scan volume, (2) 0.8-1.0cm axial slab at the center of the scan volume, and (3) the entire scan volume. Mean dose to brain parenchyma for all three regions was calculated. Mean bone dose and a mass-weighted average dose, consisting of brain parenchyma and bone, were also calculated for the slab in the central plane and the entire scan volume. All dose measures were then normalized by CTDIvol for the 16cm phantom (CTDIvol,16 ). Conversion factors were determined by calculating the relationship between normalized doses and water equivalent diameter (Dw ). CTDIvol,16 -normalized mean brain parenchyma dose values within the 0.6cc volume, 0.8-1.0cm central axial slab, and the entire scan volume, when parameterized by Dw , had an exponential relationship with a coefficient of determination (R2 ) of 0.86, 0.84, and 0.88, respectively. There was no statistically significant difference between the conversion factors resulting from these three different tally regions. Exponential relationships between CTDIvol,16 -normalized mean bone doses had R2 values of 0.83 and 0.87 for the central slab and for the entire scan volume, respectively. CTDIvol,16 -normalized mass-weighted average doses had R2 values of 0.39 and 0.51 for the central slab and for the entire scan volume, respectively. Conversion factors that describe the exponential relationship between CTDIvol,16 -normalized mean brain dose and a size metric (Dw ) for helical head CT examinations have been reported for two different interpretations of the center of the scan volume. These dose descriptors have been extended to describe the dose to bone in the center of the scan volume as well as a mass-weighted average dose to brain and bone. These may be used, when combined with other efforts, to develop an SSDE dose coefficients for routine, helical head CT examinations.

Usefulness of noncontrast MRI in differentiation between gallbladder carcinoma and benign conditions manifesting as focal mild wall thickening

BackgroundMagnetic resonance imaging (MRI) is a reliable imaging tool for evaluating gallbladder carcinoma, but it is costly and time-consuming. PurposeTo compare noncontrast MRI with multidetector row CT (MDCT) and gadoxetic acid-enhanced whole MRI in distinguishing gallbladder carcinoma from benign disease. Materials and methods101 patients (36 with gallbladder carcinoma and 65 with benign disease) with mild focal gallbladder wall thickening were included. Two radiologists reviewed the MDCT and MRI to determine the differential features between malignancy and benignity. Then, the diagnostic performance of MDCT and MRI (T1-, T2- and diffusion-weighted images) with and without gadoxetic acid enhancement in the diagnosis of gallbladder carcinoma was evaluated. ResultsThe benign group more often showed T2 necklace sign or T2 hyperintensity within the thickened wall (P < 0.0001) and T1 hyperintensity within the wall or gallbladder lumen (P = 0.0002). Meanwhile, malignancy more frequently showed T2 moderate hyperintensity of the thickened wall, papillary appearance, and diffusion restriction (all P < 0.0001). There were significant differences in sensitivity (79.2% vs 98.6% for observer 1; 84.7% vs 100% for observer 2) and specificity (80.7% vs 96.9%; 79.2% vs 95.4%) between the MDCT and noncontrast MRI (P < 0.05). We found similar diagnostic values between the noncontrast MRI and whole MRI (P = 0.479–1.000) for both observers. ConclusionNoncontrast MRI could be a useful alternative to gadoxetic acid–enhanced MRI in the diagnosis of gallbladder carcinoma that presents as mild gallbladder wall thickening on MDCT.

Gunshot Wounds: Ballistics and Imaging Findings

Ballistic traumas are defined by a projectile entering the body. Such projectiles include bullets, birdshot, and metal fragments from the covering or the contents of an explosive device. They frequently cause severe wounds characterized by a range of clinical pictures and a large spectrum of concomitant wounds. The major aims of imaging are to define the path of the projectile or projectiles, to evaluate which tissues have been injured, to estimate the severity of injury, and to determine what additional studies are needed. A routine radiograph is performed in patients with gunshot wounds. The diagnostic approach has been changed by the use of multidetector row computed tomography (MDCT) due to its technical developments particularly faster data acquisition and advanced image reconstructions. In the evaluation of patients with gunshot injuries, MDCT is considered the method of choice to identify hemorrhage, bullet, bone fragments, air, hemothorax, nerve lesions, musculoskeletal lesions, and vessel injuries. Moreover, MDCT technology and multiplanar reformation postprocessing allow meticulous trajectory analysis that potentially benefits the clinical outcomes of patients aiding time-saving triage and correct image-based diagnosis of organ and vessel damage. Familiarity of ballistics and forensic sciences will therefore help the radiologist in assessment and localization of the damage caused by projectiles.

Estimation of effective doses from MDCT and CBCT imaging of extremities

Little research has been published on the radiation burden of cone beam computed tomography (CBCT) in comparison with multi-row detector computed tomography (MDCT) for extremity imaging. This manuscript reports effective doses produced by standard and reduced dose imaging protocols for a 128-slice MDCT unit and a dedicated extremity imaging device using CBCT technology. Anthropomorphic phantoms with x-ray attenuation characteristics simulating adult hand-wrist, foot-ankle, and knee areas were modified to receive optically stimulated luminescent dosimeters (OSL). Standard and lower kVp reduced dose (Lite) exposures were compared. Effective doses for four age groups (five years old to adult) were calculated following 2007 recommendations of the ICRP. Standard CBCT imaging protocols produced effective doses (1.3–21.1 μSv) that were on the order of daily US ubiquitous background radiation doses. CBCT doses were on average 90% less than comparable MDCT views of the same anatomy (9.1–204 μSv). Child doses were significantly greater than adult doses (p = 0.0001). CBCT doses could be further reduced by 36%–51% with Lite exposure protocols. These protocols can be recommended for children and in cases where increased image noise will not interfere with the diagnostic task.