Iranian Journal of Radiology
Volume:6 Issue: 4, Autum 2009

Background/ Accurate delineation of the fistula tract anatomy is necessary for surgical management of anal fistulas. Among different ways to do this, endoanal ultrasound (EUS) is being increasingly used to evaluate patients with anal fistula. In this study we assessed the accuracy of hydrogen peroxide-enhanced EUS in detecting the internal orifice and the type of the fistula.Patients and Patients with history and physical examination compatible with fistula-in-ano underwent an injection of 1 ml hydrogen peroxide into the external orifice and then EUS with a 7.5 MHz probe was carried out prior to surgery. The location of the internal orifice, presence of the abscess and the type of the fistula were examined and the results were compared with surgical findings. Thirty-two patients entered the study. The fistula type could be identified in 29 patients (90.6%). Twenty-two (75.8%) of these patients had trans-sphincteric and seven (24.2%) had inter-sphincteric fistulas. In 11 (34.3%) patients, an abscess was found uring EUS. The fistula type was identified surgically in 29 patients, in which 26 were trans-sphincteric (89.8%), two were inter-sphincteric (6.8%), and one was extra-sphincteric (3.4%). There was a difference between detected sites of internal orifices during EUS and surgery (p value<0.001). Hydrogen peroxide-enhanced EUS had an appropriate agreement in detecting trans-sphincteric fistulas with surgery. Hydrogen peroxide-enhanced EUS is a suitable method for detecting the internal orifice of anal fistulas. It can be used for detecting trans-sphincteric fistulas, which are the most common type.

Benign multicystic mesothelioma is a very rare tumor that originates from the peritoneum and is seen more often in reproductive aged females. On CT scan a fluid density mass is seen but the final diagnosis is based on histologic examination.Hereby we report a huge multicystic benign mesothelioma in an old man.

A case of abdominal mass was studied by dynamic computed tomography (CT), magnetic resonance imaging (MRI) and hepatic angiography. The results of radiological examinations made the diagnosis even more confusing. The patient underwent laparotomy under a preoperative diagnosis of hepatic tumor. The tumor was finally diagnosed as a benign retroperitoneal neurilemmoma by histological examination. This case indicated that careful examination is necessary to determine whether it arises from the liver itself or from neighboring tissues. Radiological examinations are not reliable sometimes.

Background/ To assess whether baseline SNOT-20 and Lund-Mackay score can predict response to FESS. For 50 consecutive patients who underwent functional endoscopic sinus surgery (FESS) for chronic rhinosinusitis (CRS) in a university-affiliated hospital from January 2006 to February 2007, SNOT-20 and Lund-Mackay scores were evaluated preoperatively and after three months postoperatively. Pearson''s correlation coefficient of the Lund-Mackay score and SNOT-20 score was 0.77 before FESS and 0.73 after FESS (p <0.001). All multivariate regression models for evaluating whether the primary symptoms and CT scan findings predict the response rate showed a weak to moderate fitness to primary data based on all symptom domains and in each model, only the primary symptom domain of the dependent variable remain in the model. The outcome of FESS in patients with CRS is moderately related to primary symptoms according to SNOT-20 as well as the Lund-Mackay radiologic score.

Cemento-ossifying fibroma is an unusual benign non-odontogenic fibro-osseous tumor that is limited to the jaws and facial bones. Microscopically, some times the lesion may be confused with fibrous dysplasia, and in these cases the final definitive diagnosis requires evaluation of the radiographic configuration.In this article, the radiological features of six cases of histopathologically confirmed cemento-ossifying fibroma are described.

Congenital posterior choanal atresia is an uncommon anomaly which may have life-threatening consequences. This defect is frequently associated with other congenital abnormalities. CT scan confirms the diagnosis and accurately defines the anatomy of the atresia and differentiates osseous stenosis from membranous stenosis in the choanae. Therefore, CT may be the first-line imaging choice for the pre-operative diagnosis of congenital choanal atresia. We present two cases of bilateral bony choanal atresia, of which one is associated with bilateral coloboma.

Background/ Consistent determination of the anatomical landmarks on image or image-based three dimensional (3D) models is a basic requirement for reliable analysis of the human joint kinematics using imaging techniques. We examined the intra- and inter-observer reliability of determination of the medial and lateral epicondyle landmarks on 2D MR images and 3D MRI-based models of the knee. Sixteen coronal plane MRI recordings were taken from 18 healthy knees using a knee coil with T2-weighted fast spin-echo sequence and 512×512 pixel size. They were then processed by the Mimics software to provide the coronal and axial plane views and to create a 3D image-based model of the femur. Each image was reviewed twice, at least one-day apart. The interclass correlation coefficient, standard error of measurement, and coefficient of variation were calculated to assess the intra- and inter-observer reliability of the landmark determination by six experienced radiologists. A mixed model analysis of variance (ANOVA) with two days of observation as the within-subject factor, and observers (six radiologists) and methods (2D vs. 3D) as between-subject factors were used to test the effect of observer, two days of observation and method of evaluation on landmark determination. The results indicated that the interclass correlation coefficients for the intra-observer and inter-observer determination of landmarks on images and image-based 3D models were above 0.97. The standard error of measurement ranged between 0.41 and 0.78 mm for x; 1.35 and 3.43 mm for y; and 1.03 and 4.71 mm for z coordinates. Furthermore, the results showed no significant difference for within and between-subject comparisons of each coordinate of the lateral epicondyle as well as x and z coordinates of the medial epicondyle. For the y coordinate of the medial epicondyle, the p value of within-subject comparison was borderlinely significant (p=0.049). It was concluded that the intra- and inter-observer reliability of the bony landmark determination on both image and image-based 3D models were excellent.

Intracranial aneurysms are relatively common، with a prevalence of approximately 4%. Unruptured aneurysms may cause symptoms mainly due to a mass effect، but the real danger is when an aneurysm ruptures، leading to a subarachnoid hemorrhage. Most aneurysms are asymptomatic and will not rupture، but they grow unpredictably and even small aneurysms carry a risk of rupture. There are many risk factors for the development of intracranial aneurysms، both inherited and acquired. Females are more prone to aneurysm rupture، with subarachnoid hemorrhage (SAH) 1. 6 times more common in women. The prevalence of aneurysm increases in certain genetic diseases. There are four main types of intracranial aneurysms: saccular، fusiform (atherosclerotic or dolichoectatic type/congenital type)، dissecting، and the mycotic type. The saccular type accounts for 90% of intracranial aneurysms. We observed some patients who were referred for diagnosis and further angiographic evaluation. They had presented with various histories and clinical findings. Their imaging findings such as CT scan، CTA، MRI and MRA findings were unusual. Every one of these patients has an uncommon form of aneurysm which could be misdiagnosed with other conditions or might need special and different treatment and knowledge of these situations could be of great help.

Background/ The relaxation time T1 depends on the concentration of paramagnetic contrast agent. To calculate perfusion parameters from dynamic contrast-enhanced MRI acquisitions, measurement of the concentration is necessary. At low concentrations, the relationship between changes in 1/T1 and concentration can be considered to be linear. To maximize the concentration, and hence the signal to noise ratio (SNR) in perfusion images, the range of this linearity should be known. This work studied the effect of two repetition times (TR) on the linearity using inversion recovery Turbo Fast Low Angle Shot (TurboFLASH) sequences at different effective inversion times (TI).Patients and To assess the relationship between signal intensity (SI) and concentration, a water-filled phantom containing vials of different concentrations of Gd-DTPA (0 to 19.77 mmol/L) was used. The mean SI was obtained in the region of interest using T1-weighted images. Coil non-uniformity was corrected on SI. This study shows that an increase in TR is associated with a decrease in the maximum linear relationship between effective TI and concentration where the square correlation (R2) between corrected SI and concentration were equal to 0.95 or 0.99. In spite of TR = 2 or 3s and r2= 0.95 or 0.99 at a typical effective TI = 800ms, which is normally used for in vivo perfusion, the maximum linearity is about twice that previously reported (i.e. 0.8mmol/L) for measuring the perfusion parameters. The higher dose will improve the SNR in perfusion images.

Proximal femoral focal deficiency (PFFD) is a developmental disorder of the proximal segment of the femur and acetabulum, resulting in shortening of the affected limb and impairment of the function. It is a spectrum of congenital osseous anomalies characterized by a deficiency in the structure of the proximal femur.It is a sporadic disorder with an increased incidence in infants of diabetic mothers. Abnormality ranges from aplasia/hypoplasia of the entire femur to complete absence of the proximal end. The disorder is more commonly unilateral and is apparent at birth; however, bilateral involvement is also rarely seen.