Evaluation of dose reduction and image quality in CT colonography: comparison of low-dose CT with iterative reconstruction and routine-dose CT with filtered back projection.

OBJECTIVE: To prospectively evaluate the radiation dose and image quality comparing low-dose CT colonography (CTC) reconstructed using different levels of iterative reconstruction techniques with routine-dose CTC reconstructed with filtered back projection. METHODS: Following institutional ethics clearance and informed consent procedures, 210 patients underwent screening CTC using automatic tube current modulation for dual positions. Examinations were performed in the supine position with a routine-dose protocol and in the prone position, randomly applying four different low-dose protocols. Supine images were reconstructed with filtered back projection and prone images with iterative reconstruction. Two blinded observers assessed the image quality of endoluminal images. Image noise was quantitatively assessed by region-of-interest measurements. RESULTS: The mean effective dose in the supine series was 1.88 mSv using routine-dose CTC, compared to 0.92, 0.69, 0.57, and 0.46 mSv at four different low doses in the prone series (p < 0.01). Overall image quality and noise of low-dose CTC with iterative reconstruction were significantly improved compared to routine-dose CTC using filtered back projection. The lowest dose group had image quality comparable to routine-dose images. CONCLUSIONS: Low-dose CTC with iterative reconstruction reduces the radiation dose by 48.5 to 75.1% without image quality degradation compared to routine-dose CTC with filtered back projection. KEY POINTS: • Low-dose CTC reduces radiation dose ≥ 48.5% compared to routine-dose CTC. • Iterative reconstruction improves overall CTC image quality compared with FBP. • Iterative reconstruction reduces overall CTC image noise compared with FBP. • Automated exposure control with iterative reconstruction is useful for low-dose CTC.

Lower heart rate in the early postoperative period does not correlate with long-term outcomes after repair of type A acute aortic dissection.

Little evidence exists regarding the need for a reduction in postoperative heart rate after repair of type A acute aortic dissection. This single-center retrospective study was conducted to determine if lower heart rate during the early postoperative phase is associated with improved long-term outcomes after surgery for patients with type A acute aortic dissection. We reviewed 434 patients who underwent aortic repair between 1990 and 2011. Based on the average heart rate on postoperative days 1, 3, 5, and 7, 434 patients were divided into four groups, less than 70, 70-79, 80-89, and greater than 90 beats per minute. The mean age was 63.3 ± 12.1 years. During a median follow-up of 52 months (range 16-102), 10-year survival in all groups was 67%, and the 10-year aortic event-free rate was 79%. The probability of survival and being aortic event-free using Kaplan-Meier estimates reveal that there is no significant difference when stratified by heart rate. Cox proportional regression analysis for 10-year mortality shows that significant predictors of mortality are age [Hazard Ratio (HR) 1.04; 95% confidence interval (CI) 1.07-1.06; p = 0.001] and perioperative stroke (HR 2.30; 95% CI 1.18-4.50; p = 0.024). Neither stratified heart rate around the time of surgery nor beta-blocker use at the time of discharge was significant. There is no association between stratified heart rate in the perioperative period with long-term outcomes after repair of type A acute aortic dissection. These findings need clarification with further clinical trials.

Analysis of risk classification for massive transfusion in severe trauma using the gray zone approach.

BACKGROUND: The Traumatic Bleeding Severity Score (TBSS) was developed to predict the need for massive transfusion (MT). The aim of this study is evaluation of clinical thresholds for activation of a MT protocol using the gray zone approach based on TBSS. METHODS: This is a single-center retrospective study of trauma patients, admitted from 2010 to 2013. The TBSS on admission was calculated, and the accuracy of predicting MT was analyzed using area under the receiver operating characteristic curve. Risk classification for MT was made using sensitivity/specificity. The gray zone (indeterminate risk) was defined from a sensitivity of 95% to a specificity of 95%, patients were separated into MT and non-MT groups, and their clinical characteristics were compared. RESULTS: A total of 264 patients were enrolled, with an area under the TBSS curve of 0.967 (95% confidence interval, 0.94-0.99). A TBSS of 10 points or less resulted in a sensitivity of 96.5% with 146 patients in this group, and 3.4% (5/146) of them received MT. A TBSS of 17 points or higher had a specificity of 97.8%, which included 72 patients, and 94.4% (68/72) of them received MT. Forty-six patients had a TBSS from 11 to 16 points (gray zone), and 26.1% (12/46) of them received MT. Comparing the MT group (12/46) and non-MT group (34/46), coagulopathy and extravasation on computed tomographic scan were more prevalent in the MT group. CONCLUSION: The TBSS is highly accurate in predicting the need for MT, and a risk classification for needing MT was created based on TBSS.

Reduction in the size of enlarged pelvic lymph nodes after chemoradiation therapy is associated with fewer lymph node metastases in locally advanced rectal carcinoma.

PURPOSE: We hypothesized that a reduction in the size of the lymph nodes after neoadjuvant therapy for locally advanced rectal carcinoma would be associated with decreased lymph node metastases and/or a better prognosis. METHODS: Between March 2006 and April 2012, 71 patients with primary rectal cancer received neoadjuvant chemoradiation therapy (CRT). For all lymph nodes 5 mm or larger in size, the major and minor axes were measured on CT scan images, and the product was calculated. The lymph node size was determined before and after CRT. The patients were divided into three groups based on the lymph node size before and after treatment. Group A exhibited a reduction in size of 60% or more, Group B a reduction of less than 60% and Group C had no lymph node enlargement before treatment. RESULTS: The incidence of lymph node metastases on pathological examination was 15% in Group A and 50% in Group B (p = 0.006). The five-year disease-free survival in Group A was 84% compared with 78% in Group B (log rank p = 0.34). The five-year overall survival in Group A was 92% compared with 74% in Group B (log rank p = 0.088). CONCLUSIONS: A reduction in the size of enlarged lymph nodes after neoadjuvant therapy may be a useful prognostic factor for recurrence and survival.

Utility of a new reusable clip device for endoscopic treatment.

BACKGROUND AND AIM: Existing reusable endoscopic clip devices have some problems regarding opening the device and precise control of clip application. The aim of the present study was to evaluate reusable clip devices for endoscopic treatment. METHODS: Ability to close a large defect and grip force were evaluated using ex-vivo porcine colon. We assessed clip loading and opening in a non-clinical setting and describe the resulting learning curve. To evaluate clinical utility, data for clip application in 72 post-endoscopic mucosal resection (EMR) defects in 40 patients were retrospectively analyzed. RESULTS: There was no difference in the ability to close a 20-mm full-thickness defect and the grip force comparing the new clip device (ZEOCLIP®) and a previously used reusable clip device (EZClip®). Although the time to load the ZEOCLIP was almost same as the EZClip, the time to open the ZEOCLIP was significantly shorter than the EZClip (P < 0.001). Opening width of the ZEOCLIP was significantly wider than the EZClip (P < 0.05). We successfully accomplished closure of post-EMR defects by clip application in 72 lesions using ZEOCLIP. Reopening/repositioning and restoring it to the working channel were more frequently carried out in a non-easy location than in an easy location (11/35 [31%] vs 4/37 [11%], P = 0.030; and 21/35 [60%] vs 1/37 [3%], P < 0.001, respectively). CONCLUSIONS: ZEOCLIP is more quickly and easily opened to its maximum width compared with EZClip, and is feasible for clip application after EMR.

The three-step method for ultrasound-guided pediatric internal jugular venous catheterization: a clinical trial.

Ultrasound guidance may be a valuable adjunct for pediatric internal jugular vein catheterization. We previously reported a long-axis in plane technique, called the "three-step method", resulting in high success and a low complication rate by novice operators in adult patients. This is the first report of ultrasound-guided internal jugular vein catheterization (US-IJV) using the three-step method in pediatric patients. Fourteen junior residents underwent simulation training, and then participated in a clinical trial. They performed US-IJV in 14 pediatric patients with congenital heart disease before undergoing cardiac surgery under supervision of an experienced clinician. The overall success rate was 93 %, and all catheterizations were performed within two venipunctures. There were no complications associated with the procedure. The three-step method may facilitate pediatric US-IJV even by a novice operator during their first experience.

Analysis of hand motion differentiates expert and novice surgeons.

BACKGROUND: The number of operations performed by a surgeon may be an indicator of surgical skill. The hand motions made by a surgeon also reflect skill and level of expertise. We hypothesized that the hand motions of expert and novice surgeons differ significantly, regardless of whether they are familiar with specific tasks during an operation. METHODS: This study compared 11 expert surgeons, each of whom had performed >100 laparoscopic procedures, and 27 young surgeons, each of whom had performed <15 laparoscopic procedures. Each examinee performed a specific skill assessment task, in which instrument motion was monitored using magnetic tracking system. We analyzed the paths of the centers of gravity of the tips of the needle holders and the relative paths of the tips using two mathematical methods of detrended fluctuation analysis and unstable periodic orbit analysis. RESULTS: Detrended fluctuation analysis showed that the exponent in the function describing the initial scaling exponent (α1) differed significantly for experts and novices, being close to 1.0 and 1.5, respectively (P < 0.01). This indicated that the expert group had a greater long-range coherence with an intrinsic sequence and smooth continuity among a series of motions. Likewise, unstable periodic orbit analysis showed that the second period of unstable orbit was significantly longer for experts in comparison with novices (P < 0.01). This demonstrates mathematically that the hands of experts are more stable when performing laparoscopic procedures. CONCLUSIONS: Objective evaluation of hand motion during a simulated laparoscopic procedure showed a significant difference between experts and novices.

Endoscopic ultrasound with double-balloon endoscopy in the evaluation of small-bowel disease.

BACKGROUND: Double-balloon endoscopy (DBE) has become a new standard in enteroscopy. However, it may be difficult to make a diagnosis or plan treatment strategy with endoscopic visualization alone. The addition of endoscopic ultrasonography (EUS) has the potential to improve the ability to establish the diagnosis and develop a treatment strategy. The present study was conducted to assess the feasibility and usefulness of EUS with DBE. METHODS: EUS with DBE was performed in 31 of 891 patients who underwent DBE from July 2004 to March 2011 at Jichi Medical University Hospital. We analyzed the EUS findings for lesions and evaluated the usefulness of EUS considering the following three factors: qualitative diagnostic value for lesions, depth grading of lesions, and evaluation of the structure of severe strictures prior to endoscopic balloon dilation. RESULTS: EUS was performed for 31/32 lesions (97%) in 31 patients. EUS findings were informative for 29/32 lesions (91%). EUS findings were useful for establishing a qualitative diagnosis in 15/25 lesions (60%). EUS findings for depth grading provided useful information for determining the therapeutic strategy in 11/13 lesions (85%). EUS with DBE was useful in the evaluation of strictures for all six lesions (100%). The overall usefulness of EUS with DBE on decision making was 72% (23/32) in this study. CONCLUSIONS: EUS with DBE is feasible and useful. It provides additional information on small-bowel disease and contributes to establishing a precise diagnosis and selection of an appropriate therapeutic strategy.

A case of mixed adenoneuroendocrine carcinoma of the gallbladder arising from an intracystic papillary neoplasm associated with pancreaticobiliary maljunction.

A 54-year-old Japanese woman was referred with a gallbladder tumor. Based on the results of the computed tomography scan, endoscopic retrograde cholangiopancreatography, and magnetic resonance cholangiopancreatography, a mucin-producing neoplasm of the gallbladder associated with pancreaticobiliary maljunction was diagnosed. Extended cholecystectomy, extrahepatic bile duct resection, and choledochojejunostomy were performed, and she remains free of recurrence 24 months after resection. Histopathological examination revealed that the papillary component of the lesion was an intracystic papillary neoplasm with diverse characteristics of pancreaticobiliary epithelium and intestinal epithelium including mucin. In this component, most of the papillary lesion was a high-grade intraepithelial neoplasm, but also showed slight invasion into the muscular layer. The nodular component consisted of both poorly differentiated biliary type adenocarcinoma and large cell neuroendocrine carcinoma. We report a rare case of a mixed adenoneuroendocrine carcinoma arising from an intracystic papillary neoplasm associated with pancreaticobiliary maljunction. As for the histogenesis of this tumor, based on the histopathologic appearance, transdifferentiation from poorly differentiated biliary type adenocarcinoma to large cell neuroendocrine carcinoma is considered the most possible histogenesis of this tumor.

Serum ghrelin levels partially recover with the recovery of appetite and food intake after total gastrectomy.

PURPOSE: Ghrelin may lead to weight gain by appetite stimulation. This prospective study investigated the association between weight loss and the ghrelin levels in patients after gastrectomy. METHODS: Thirty-three males and eight females were enrolled in the study. The average age was 66 years. Measurements of the serum ghrelin level and an appetite questionnaire were performed preoperatively and at one, three, six and 12 months postoperatively. RESULTS: The preoperative serum total ghrelin level was 51.6 ± 31.9 (fmol/ml ± SD), and that at one, three, six and 12 months postoperatively was 16.9 ± 9.0, 21.2 ± 16.0, 28.0 ± 19.1 and 29.6 ± 20.6 (fmol/ml ± SD), respectively. The appetite score was 2.02 ± 1.09 points at 1 month, and increased significantly to 2.61 ± 1.00 by 12 months. CONCLUSIONS: The ghrelin levels were reduced after gastrectomy and did not recover by 12 months postoperatively. Further studies are needed to evaluate these results as the basis of a therapeutic trial.

Primary and secondary adenocarcinomas associated with anal fistulae.

PURPOSE: The purpose of this study was to evaluate the clinical features, pathology, and etiology of adenocarcinoma in patients with anal fistulae. METHODS: We identified seven patients diagnosed with adenocarcinoma associated with anal fistulae from a retrospective chart review. RESULTS: Five patients were diagnosed with primary adenocarcinoma associated with anal fistulae. Two patients were diagnosed with secondary adenocarcinoma associated with anal fistulae originating from rectal cancer on the proximal side. The primary adenocarcinomas included cancers arising from long-standing anal fistulae fulfilling established diagnostic criteria in two patients, and cancer arising from short-duration anal fistulae in three patients. Excision of the fistula was performed based on the initial diagnosis of the anal fistula for all five patients. Increased suspicion of cancer was due to the existence of gelatinous material in the anal fistula in three patients and induration in the resected specimens in two patients. The etiologies of the secondary adenocarcinomas associated with anal fistulae included implantation in the anal fistula from rectal cancer and fistula formation originating due to the progression of rectal cancer. CONCLUSION: Anal fistulae are commonly seen in the coloproctology clinic, but special attention to similar conditions associated with malignant disease is needed.

Stenosis after use of the double-stapling technique for reconstruction after laparoscopy-assisted total gastrectomy.

BACKGROUND: The double-stapling technique (DST) for esophagojejunostomy using the transorally inserted anvil (OrVil; Covidien Japan, Tokyo, Japan) is one of the reconstruction methods used after laparoscopy-assisted total gastrectomy (LATG). This technique has potential advantages in terms of less invasive surgery without the need to create a complicated intraabdominal anastomosis. METHODS: From 2008 to 2011, 262 patients with gastric cancer underwent total gastrectomy and reconstruction with a Roux-en-Y anastomosis, and 52 patients underwent LATG with DST. A retrospective analysis then was performed comparing the patients who experienced postoperative stenosis after LATG-DST (positive group) and the patients who did not (negative group). A comparative analysis was performed among patients comparing conventional open total gastrectomy and LATG, and multivariate analysis was performed to evaluate risk factors for the development of anastomotic stenosis. RESULTS: A minor leak was found in 1 patient (1.9 %), and 11 patients experienced anastomotic stenosis (21 %) after LATG with DST. Among the patients with anastomotic stenosis, three (3/4, 75 %) anastomoses were performed with the 21-mm end-to-end anastomosis (EEA) stapler, and eight anastomoses were performed (8/47, 17 %) with the 25-mm EEA stapler. The median interval to the diagnosis of anastomotic stenosis was 43 days after surgery. The patients with stenosis needed endoscopic balloon dilation an average of four times, and the rate of perforation after dilation was 13 %. The clinical and operative characteristics did not differ between the two groups. Anastomotic stenosis after open total gastrectomy occurred in two cases (0.98 %). Multivariate analysis showed that the size of the EEA stapler and the use of DST were risk factors for anastomotic stenosis. CONCLUSION: Esophagojejunostomy using DST with OrVil is useful in performing a minimally invasive procedure but carries a high risk of anastomotic stenosis.

Floating gallbladder strangulation caused by the lesser omentum: report of a case.

Strangulation of the gallbladder by the omentum is extremely rare. We report what to our knowledge is only the second documented case of strangulation of a floating gallbladder by the lesser omentum. A 61-year-old Japanese woman presented to a local hospital after the sudden onset right upper quadrant pain. Her clinical features suggested a gallbladder volvulus, and the patient was referred to our hospital for investigation and treatment. Ultrasonography and computed tomography showed no cholecystolithiasis, but the fundus and body of the gallbladder were markedly swollen without wall thickening, whereas the neck of the gallbladder was normal. A narrowed, twisted area was seen between the body and neck of the gallbladder. Based on these findings, gallbladder volvulus was diagnosed and she underwent emergency laparoscopic cholecystectomy. The fundus and body of the gallbladder were grossly necrotic. The narrowest part of the gallbladder was tightly strangulated by the lesser omentum, but the gallbladder neck was normal. Histopathologic examination of the resected gallbladder showed ischemic changes in the wall of the fundus and body. This case highlights that the clinical features and imaging findings of a gallbladder strangulated by the lesser omentum are similar to those of gallbladder volvulus and that a positive outcome is dependent on a correct diagnosis and prompt surgical management.

Extent of gastric resection impacts patient quality of life: the Dysfunction After Upper Gastrointestinal Surgery for Cancer (DAUGS32) scoring system.

BACKGROUND: Quality of life is an important outcome measure in the care of patients with cancer. We developed a new scoring system specifically for the evaluation of patients with upper gastrointestinal cancer and postoperative gastrointestinal dysfunction. This study was undertaken to evaluate the scoring system's validity in comparing outcomes after gastric resection. MATERIALS AND METHODS: Patients with gastric cancer, 3 months to 3 years postoperatively, were surveyed using the survey instrument. Postoperative dysfunction scores and the status of resuming activities of daily living were compared with the surgical procedure performed by analysis of variance and multiple-comparison techniques. RESULTS: Of 211 patients surveyed, 165 (119 men, 46 women; mean age, 65.1 ± 10.5 years) responded. Procedures included distal gastrectomy in 100, total gastrectomy in 57, and pylorus-preserving gastrectomy in 8. The overall dysfunction score was 61.8 ± 15.5. The dysfunction score was 58.9 ± 15.0 after distal gastrectomy, 66.8 ± 14.1 after total gastrectomy, and 62.4 ± 21.6 after pylorus-preserving gastrectomy. These values differed significantly among the groups (P = .007). Dysfunction scores according to postoperative activity status were 49.1 ± 15.6 in 71 patients who resumed their activities, 56.9 ± 15.7 in 39 patients with reduced activities, 57.3 ± 8.8 in 15 patients with minimal activities, and 63.3 ± 11.8 (P < .05) in 16 patients who did not resume activities because of poor physical condition. CONCLUSIONS: This scoring system for postoperative gastrointestinal dysfunction provides an objective measure of dysfunction related to specific surgical procedures and correlates with activities of daily living in the postoperative period.

Biceps pulley: normal anatomy and associated lesions at MR arthrography.

The biceps pulley or "sling" is a capsuloligamentous complex that acts to stabilize the long head of the biceps tendon in the bicipital groove. The pulley complex is composed of the superior glenohumeral ligament, the coracohumeral ligament, and the distal attachment of the subscapularis tendon, and is located within the rotator interval between the anterior edge of the supraspinatus tendon and the superior edge of the subscapularis tendon. Because of its superior depiction of the capsular components, direct magnetic resonance arthrography is the imaging modality of choice for demonstrating both the normal anatomy and associated lesions of the biceps pulley. Oblique sagittal images and axial images obtained with a high image matrix are valuable for identifying individual components of the pulley system. Various pathologic processes occur in the biceps pulley as well as the rotator interval. These processes can be traumatic, degenerative, congenital, or secondary to injuries to the surrounding structures. The term hidden lesion refers to an injury of the biceps pulley mechanism and is derived from the difficulty in making clinical and arthroscopic identification. Pathologic conditions associated with pulley lesions include anterosuperior impingement, instability of the biceps tendon, biceps tendinopathy or tendinosis, superior labrum anterior and posterior lesions, and adhesive capsulitis. It is important to be familiar with the normal appearance of the biceps pulley so that abnormalities can be correctly assessed and effectively managed.

Computational oncology.

Oncology research has traditionally been conducted using techniques from the biological sciences. The new field of computational oncology has forged a new relationship between the physical sciences and oncology to further advance research. By applying physics and mathematics to oncologic problems, new insights will emerge into the pathogenesis and treatment of malignancies. One major area of investigation in computational oncology centers around the acquisition and analysis of data, using improved computing hardware and software. Large databases of cellular pathways are being analyzed to understand the interrelationship among complex biological processes. Computer-aided detection is being applied to the analysis of routine imaging data including mammography and chest imaging to improve the accuracy and detection rate for population screening. The second major area of investigation uses computers to construct sophisticated mathematical models of individual cancer cells as well as larger systems using partial differential equations. These models are further refined with clinically available information to more accurately reflect living systems. One of the major obstacles in the partnership between physical scientists and the oncology community is communications. Standard ways to convey information must be developed. Future progress in computational oncology will depend on close collaboration between clinicians and investigators to further the understanding of cancer using these new approaches.

Mannequin simulation improves the confidence of medical students performing tube thoracostomy: a prospective, controlled trial.

This study was undertaken to determine the educational benefits of mannequin simulation for performance of tube thoracostomy in a porcine model by medical students. Thirty medical students were randomized into two groups; the first performed tube thoracostomy on a mannequin simulator and then a porcine model; the second used only the porcine model. Performance measures included completion of subtasks, time to perform the procedure, a global score assigned by faculty raters, and a self-evaluation survey. Subtask completion rate was similar in both groups (P > 0.05). Mean time to perform the procedure was 9.8 minutes (+/- 0.9, simulator), and 9.3 minutes (+/- 1.0, nonsimulator, P > 0.05). Global scores were 12.3 (+/- 1.3, simulator) and 11.0 (+/- 1.4, non-simulator, P > 0.05). Self-evaluation of confidence (1 = "very", 7 = "not at all") showed the simulator group was significantly more confident (3.4 +/- 0.42) than the nonsimulator group (4.7 +/- 0.49, P < 0.05). All students met basic competencies to perform tube thoracostomy. The simulator group felt significantly more confident to subsequently perform the procedure on a patient, whereas performance was not statistically significantly different for the two groups. Further trials may be needed to delineate the optimal role for these simulators in teaching tube thoracostomy.

Virtual enteroscopy using air as the contrast material: a preliminary feasibility study.

BACKGROUND: There are no studies to date using air as an enteral contrast medium for small bowel expansion in virtual enteroscopy. We examine the feasibility of air as an enteral contrast medium for virtual enteroscopy to achieve small bowel expansion. PATIENTS AND METHODS: Two volunteers and six patients were examined. The six patients included three with small bowel tumors, one with small bowel hemorrhage and two with suspected cases of post-operative small bowel stenosis. A duodenal tube was inserted under fluoroscopy and approximately 2000 ml air was administered prior to scanning. A 16-detector row computed tomography apparatus was used with 2-mm thick slices. Intravenous contrast material was administered to the patients, but not to the volunteers. Computed tomography scanning was performed two to three times until the air reached the colon. Two examiners reconstructed multi-planar reformation, volume rendering and virtual endoscopy. These images were compared with double balloon enteroscopic findings and/or resected specimens. RESULTS: There were no complications associated with this examination. In the volunteers the difference between the circular folds of the jejunum and those of the ileum was clearly visualized on virtual endoscopy. Angiodysplasia (9 mm), gastrointestinal stromal tumor (15 mm) and arteriovenous malformation were clearly detected by virtual endoscopy. In contrast, one tumor could not be detected because of inadequate intestinal distension. In the two suspected cases of the stenosis, the lesion was not identified because stenotic lesions were not differentiated from normal peristalsis of the small bowel. CONCLUSIONS: Air is a feasible enteral contrast material for virtual enteroscopy.