Enhanced CT and CT virtual endoscopy in diagnosis of heterotopic pancreas

AIM:To improve the diagnosis of heterotopic pancreas by the use of contrastenhanced computed tomography(CT)imaging and CT virtual endoscopy(CTVE).METHODS:A total of six patients with heterotopic pancreas,as confirmed by clinical pathology and immunohistochemistry in the Sixth Affiliated People's Hospital of Shanghai Jiao Tong University,Shanghai,China,were included.Nonenhanced CT and enhanced CT scanning were performed,and the resulting images were reviewed and analyzed using threedimensional postprocessing software,including CTVE.RESULTS:Four males and two females were enrolled.Several heterotopic pancreas sites were involved;three occurred in the stomach,including the gastric antrum(n =2)and lesser curvature(n=1),and two were in the duodenal bulb.Only one case of heterotopic pancreas lesion occurred in the mesentery.Four cases had a solid yet soft tissue density that had a homogeneous pattern when viewed by enhanced CT.Additionally,their CT values were similar to that of the pancreas.The ducts of the heterotopic pancreas tissue,one of the characteristic CT features of heterotopic pancreas tissue,were detected in the CT images of two patients.CTVE images showed normal mucosa around the tissue,which is also an important indicator of a heterotopic pancreas.However,none of the CTVE images showed the typical signs of central dimpling or umbilication.CONCLUSION:CT,enhanced CT and CTVE techniques provide useful information about the location,growth pattern,vascularity,and condition of the gastrointestinal wall around heterotopic pancreatic tissue.

Virtual endoscopy of the urinary tract

Technological breakthroughs have advanced the temporal and spatial resolutions of diagnostic imaging, and 3 dimensional （3-D） reconstruction techniques have been introduced into everyday clinical practice. Virtual endoscopy （VE） is a non-invasive technique that amplifies the perception of cross-sectional images in the 3-D space, providing precise spatial relationships of pathological regions and their surrounding structures. A variety of computer algorithms can be used to generate 3-D images, taking advantage of the information inherent in either spiral computed tomography or magnetic resonance imaging （MRI）. VE images enable endoluminal navigation through hollow organs, thus simulating conventional endoscopy. Several clinical studies have validated the diagnostic utility of virtual cystoscopy, which has high sensitivity and specificity rates in the detection of bladder tumor. Published experience in the virtual exploration of the renal pelvis, ureter and urethra is encouraging but still scarce. VE is a safe, non-invasive method that could be applied in the long-term follow-up of patients with ureteropelvic junction obstruction, urinary bladder tumors and ureteral and/or urethral strictures. Its principal limitations are the inability to provide biopsy tissue specimens for histopathologic examination and the associated ionizing radiation hazards （unless MR/is used）. However, in the case of endoluminal stenosis or obstruction, VE permits virtual endoluminal navigation both cephalad and caudal to the stenotic segment. To conclude, VE provides a less invasive method of evaluating the urinary tract, especially for clinicians who are less familiar with cross-sectional imaging than radiologists. （Asian J Androl 2006 Jan; 8： 31-38）

Computed tomography virtual endoscopy with angiographic imaging for the treatment of type Ⅳ-A choledochal cyst

Type Ⅳ-A choledochal cysts (CCs) are a congenital biliary anomaly which involve dilatation of the extrahepatic and intrahepatic bile ducts. We present the case of a 30-year-old woman with type Ⅳ-A CC, on whom threedimensional computed tomography (3D CT) and virtual endoscopy were performed. 3D CT revealed partial dilatation in the posterior branch of the intrahepatic bile duct and a relative stricture between it and the extrahepatic bile duct. Virtual endoscopy showed that this stricture was membrane-like and separated from the surrounding blood vessels. Based on these image findings, complete cyst resection, bile duct plasty for the stricture, and hepaticojejunostomy were safely performed. To the best of our knowledge, there are no reports of imaging by virtual endoscopy of the biliary tract which show the surrounding blood vessels running along the bile duct.

CT VIRTUAL ENDOSCOPY IN ASSESSING OSSICULAR CHAIN DISRUPTION CSUSED BY TEMPORAL BONE FRACTURE AND EAR TRAUMA

Objective To explore the value of computed tomography virtual endoscopy(VE) in assessing ossicular chain disruption in temporal bone fracture and ear trauma with intact tympanum. Methods High resolution spiral computerized tomography(CT) was completed in 35 cases of temporal bone fracture and 5 cases of tympanum trauma, all with intact or healed tympanum. Three-dimensional reconstruction was completed using a virtual endoscopy software. Audiological tests were conducted in all patients and evaluation of facial nerve injury in patients with facial paralysis. Patients with mild conductive deafness, ossicular chain subluxation on VE, and no facial paralysis were treated conservatively for 4-12 weeks with repeated hearing evaluation; those with facial paralysis underwent surgery if no recovery after 4- 8 weeks of conservative treatment. Patients with moderate to severe conductive hearing loss or mixed hearing loss, incus long process fracture or dislocation on VE and facial paralysis, underwent ossicular chain reconstruction and facial nerve decompression after conservative treatment for 4-8 weeks, or exploratory tympanotomy only if no facial paralysis. VE, audiological tests and facial nerve function tests were repeated in 3-6 months after surgery. Results Of the 6 cases with mild conductive hearing loss, ossicular chain subluxation and no facial paralysis, 3recovered to normal hearing spontaneously and 3 showed no significant improvement, after 4-12 weeks of conservative treatment. After conservative treatment for 4-8 weeks, 3 of the 12 cases with mild conductive deafness, ossicular chain dislocation on VE and facial paralysis recovered to normal hearing and HouseBrackmann(HB) grade I facial function from HB grade II,4 showed facial function recovery to HB grade I(n=2) or II(n=2) from HB grade III but no hearing recovery, and 5 gained no recovery and went on to receive exploratory tympanotomy and facial nerve decompression. The 11 cases with moderate to severe conductive deafness, incus long process fracture or dislocation on VE and facial paralysis all received ossicular chain reconstruction and facial nerve decompression after 4-8 weeks of conservative treatment. The 7 cases with moderate to severe conductive deafness, dislocated or fallen incus on VE but no facial paralysis received ossicular chain reconstruction after conservative treatment. The 4 cases with mixed hearing loss, dislocated or fallen incus on VE and no facial paralysis received ossicular chain repair via the intact canal wall epitympanum approach after conservative treatment. Pharmacological therapies continued postoperatively in these patients to treat sensorineural deafness. Although temporal bone CT scans displayed the fracture line and malleus/incus abnormalities, VE provided additional detailed information on dislocation of incudomalleal and incudostapedial joints, incus dislocation or fracture, separation between crus longum incudis and stapes, and incus shifting. These were all confirmed during surgery. VE results and surgery findings were 100% consistent in patients with ossicular chain disruption. Conclusion VE can provide reliable visual evidence for accurate assessment of traumatic ossicular chain disruption, timing of surgery and individualizing surgical strategies and postoperative follow-up.

CT virtual endoscopy of the auditory ossicular chain: clinical applications

Objective To evaluate the clinical applications and limitations of CT virtual endoscopy (CTVE) in theauditory ossicular chain.Methods CTVE of the auditory ossicular chain was performed with 1.0 mm collimation at pitch 1.0, bone algorithm, 9.6 cm field of view, and 0.1 - 0.2 mm reconstruction interval in 40 patients with middle ear diseases. 30 cases were confirmed by surgery. Results were compared with the findings of axial high resolution CT (HRCT) and multiplanar reformation (MPR) images and surgery.Results The accuracy of CTVE images in detecting ossicular destruction was 92.6%, significantly higher than that of axial HRCT (83.9%) and multiplanar reformation (76.5%) images. CTVE could also clearty reveal the postoperative condition and congenital dysplasia of the auditory ossicular chain.Conclusions CTVE can clearly demonstrate a three-dimensional image of the auditory ossicular chain and is useful in evaluating diseases of the ear, especially the auditory ossicles. CTVE could not clearly demonstrate abnormal soft tissue within the tympanic cavity, abnormal changes of the tympanic membrane and tympanic walls, and could be easily influenced by artificial factors.

Comparison of CT virtual endoscopy with electronic colonoscopy in 30 colonic carcinoma patients

Abstract:Objective To evaluate the clinical application of CT virtual endoscopy (CTVE) in the diagnosis and treatment of colonic carcinoma. Methods We collected 30 patients pathologically proven to have colonic carcinomas as examined by CTVE and electronic colonoscopy (EC), correlating the CTVE and EC images respectively with surgical pathology in three aspects: tumor morphological features, degree of circumferential bowel wall involvement and longitudinal extent of tumor. Results CTVE imaging of colonic carcinomas showed morphological features: polypoid pattern (11 patients), ulcerative pattern (11), and infiltrative pattern (8); degree of circumferential bowel wall involvement: less than 1/2 (4 patients), from 1/2 to 3/4 (6), and more than 3/4 (20); and their longitudinal extent: 1.0-3.0?cm (7 patients), 31-5.0?cm (10), and 5.1-11.0?cm (13). Correlation of CTVE and EC with surgical pathology was found. Comparison of CTVE with surgical pathology showed tumor morphological features: concordant (26 patients), and disconcordant (4); degree of circumferential bowel wall involvement: concordant (25), disconcordant (5); and longitudinal extent of the tumor: concordant (23), disconcordant (7). Comparison of EC with surgical pathology showed tumor morphological features: concordant (22 patients), disconcordant (8); degree of circumferential bowel wall involvement: concordant (28), disconcordant (2); and longitudinal extent of the tumor: concordant (14), disconcordant (3), and undefined by EC (13). Conclusions The images obtained by CTVE in colonic carcinoma are similar to those obtained by EC. CTVE is an excellent alternative to EC for patients who cannot tolerate EC and for cases with incomplete EC.

Novel virtual nasal endoscopy system based on computed tomography scans

Background Currently,many simulator systems for medical procedures are under development.These systems can provide new solutions for training,planning,and testing medical practices,improve performance,and optimize the time of the exams.However,to achieve the best results,certain premises must be followed and applied to the model under development,such as usability,control,graphics realism,and interactive and dynamic gami-fication.Methods This study presents a system for simulating a medical examination procedure in the nasal cavity for training and research purposes,using a patient′s accurate computed tomography(CT)as a reference.The pathologies that are used as a guide for the development of the system are highlighted.Furthermore,an overview of current studies covering bench medical mannequins,3D printing,animals,hardware,software,and software that use hardware to boost user interaction,is given.Finally,a comparison with similar state-of-the-art studies is made.Results The main result of this work is interactive gamification techniques to propose an experience of simulation of an immersive exam by identifying pathologies present in the nasal cavity such as hypertrophy of turbinates,septal deviation adenoid hypertrophy,nasal polyposis,and tumor.

Congenital tracheoesophageal fistula successfully diagnosed by CT esophagography

Tracheoesophageal fistula （TEF） or bronchoesophageal fistula may be congenital, inflammatory, neoplastic, or secondary to trauma. Congenital TEF or bronchoesophageal fistula is usually associated with esophageal atresia and is readily diagnosed in infancy. But if it is not associated with esophageal atresia, it may persist until adulthood. Some theories have been proposed to explain this delay in diagnosis. We present a case of a 70-year-old man with congenital TEF. The TEF was successfully diagnosed by multidetector-row CT esophagography.

Sonography of the small intestine

In the last two decades, there has been substantial development in the diagnostic possibilities for examining the small intestine. Compared with computerized tomography, magnetic resonance imaging, capsule endoscopy and double-balloon endoscopy, ultrasonography has the advantage of being cheap, portable, flexible and user-and patient-friendly, while at the same time providing the clinician with image data of high temporal and spatial resolution. The method has limitations with penetration in obesity and with intestinal air impairing image quality. The flexibility ultrasonography offers the examiner also implies that a systematic approach during scanning is needed. This paper reviews the basic scanning techniques and new modalities such as contrast-enhanced ultrasound, elastography, strain rate imaging, hydrosonography, allergosonography, endoscopic sonography and nutritional imaging, and the literature on disease-specific findings in the small intestine. Some of these methods have shown clinical benefit, while others are under research and development to establish their role in the diagnostic repertoire. However, along with improved overall image quality of new ultrasound scanners, these methodshave enabled more anatomical and physiological changes in the small intestine to be observed. Accordingly, ultrasound of the small intestine is an attractive clinical tool to study patients with a range of diseases.

Colorectal neoplasm:Magnetic resonance colonography with fat enema-initial clinical experience

AIM： To assess Magnetic resonance colonography with fat enema as a method for detection of colorectal neoplasm.METHODS： Consecutive twenty-two patients underwent MR colonography with fat enema before colonoscopy. Tl-weighted three-dimensional fast spoiled gradient- echo with inversion recovery sequence was acquired with the patient in the supine position before and 75 s after Gadopentetate Dimelumine administration. Where by, pre and post MR coronal images were obtained with a single breath hold for about 20 s to cover the entire colon. The quality of MR colonographs and patients＇ tolerance to fat contrast medium was investigated. Colorectal neoplasms identified by MR colonography were compared with those identified on colonoscopy and sensitivity of detecting the lesions was calculated accordingly.RESULTS： MR colonography with fat enema was well tolerated without sedation and analgesia. 120 out of 132 （90.9%） colonic segments were well distended and only 1 （0.8%） colonic segment was poor distension. After contrast enhancement scan, mean contrast-to-noise ratio （CNR） value between the normal colonic wall and lumen was 18.5 ± 2.9 while mean CNR value between colorectal neoplasm and lumen was 20.2± 3.1. By Magnetic resonance colonography, 26 of 35 neoplasms （sensitivity 74.3%） were detected. However, sensitivity of MRC was 95.5% （21 of 22） for neoplasm larger than 10 mm and 55.6% （5 of 9） for 5-10 mm neoplasm.CONCLUSION： MR colonography with fat enema and Tl-weighted three-dimensional fast spoiled gradientecho with inversion recovery sequence is feasible in detecting colorectal neoplasm larger than 10 mm.

A proximal entry tear located in the proximal trunk of the left subclavian artery is confirmed by balloon inflation blocking and sealed with an occluder

Aortic dissection （AD） is a catastrophic disease involving the aorta. Most intimal tears are located in the ascending aorta or the first portion of the descending aorta.1 It is a rare case that the proximal tear originates from the left subclavian artery （LSA）. Virtual endoscopy （VE） technology could provide us a specific perspective to see from intraluminal to the outside and was especially helpful to look for and indentify complicated intimal tears.^2 Vascular occluder is a useful device to treat vessel diseases alone or combined with other appratus.