role of magnetic resonance imaging in perianal fistula

Anorectal abscesses originate from infection arising in the cryptoglandular epithelium lining the anal canal. Infection of the stagnant glandular secretions results in abscess formation within the anal gland. The internal anal sphincter is believed to serve normally as a barrier to infection passing from the gut lumen to the deep peri- rectal tissues. This barrier can be breached through the crypts of Morgagni, which can penetrate through the internal sphincter into the intersphincteric space; there it has easy access to the adjacent perirectal spaces. Extension of the infection can involve the intersphincteric space, ischiorectal space, or even the supralevator space. Anorectal fistulas occur in 30-60% of patients with anorectal abscesses, other etiologies of anorectal fistulas are multifactorial and include diverticular disease, irritable bowel disease [IBD], malignancy, and complicated infections such as tuberculosis or actinomycosis. Clinical evaluation of these conditions is not sufficient and conventional fistulogram is non-favorable technique for patients and radiologists, so the role of MRI in the pelvis with different pulse sequences was studied in many centers, however no full agreement about the most suitable cost effective MRI technique to evaluate these patients. To evaluate the best pelvic magnetic resonance imaging protocol for different types of perianal fistulae to visualizes its extent and anatomical relations. Fifty patients with clinical evidence of anal fistulas underwent pelvic MRI performed with phased-array coil. Images were obtained in the axial and coronal planes using T2-weighted high resolution sequences with and without fat suppression and TI-weighted sequences, with and without fat suppression, before and after gadolinium enhancement, STIR and gradient Tl and T2. The following parameters were considered: presence of a fistula and relation with the sphincters, and presence of abscesses or side tracts. All patients underwent surgery. The MRI and surgical findings were assessed using the St. James MR imaging classification of perianal fistulas. Patients were thirty one males and nineteen females.The average age was twenty eight years. Grade I, [linear intersphicteric] perianal fistula were detected in 15 [30%] patients. Grade 2, [linear intersphicteric with abscess] perianal fistula were detected in 19 [38%] patients. Grade 3, [perianal fistula were detected in 5 [10%] patients. Grade 4, [trans-sphincteric with abscess] perianal fistula were detected in 5 [10%] patients. Grade 5, [translevator with or without abscess.] perianal fistula were detected in 6 [12%] patients. All fistulae were well seen in axial STIR sequences. Post contrast studies were more accurate in delineation of the abscess wall formation. T2 with fat sat was more accurate to delineate fine side branches. Axial planes were more sensitive to delineate the level of orifice entry into the anal canal. magnetic resonance imaging is a reliable technique to evaluate the perianal fistluae, it is well tolerated form patients and it is easier for the radiologist as no need to canulate the fistula. Three MRI sequences are recommended for full evaluation of perianal fistula and abscess. Axial STIR T2 sequences' are sensitive and should be done to delineate the level of orifice entry to the anal canal, followed by axial T2 with fat saturation to anal anatomical relations with fistula and coronal post contrast Tl weighted with fat saturation to differniate old scars from the wall of abscess cavity

role of MRI in the diagnosis of vertebrobasilar dolicoectasia

Aging changes especially when it is associated with hypertension and arteriosclerosis may lead to elongation, dilatation and so tortuosity of the involved arteries. The clinical effect of this is either pressure symptoms or ischemic events. This phenomenon is called Dolicoectasia. It is defined as fusiform dilatation and elongation of an artery. The process can involve vertebral, basilar, posterior or anterior inferior cerebellar or labyrinthine arteries, The Vertebrobasilar system is more commonly involved by this process. The clinical presentations are non specific and could be related to wide range of pathological vascular and non vascular causes. The aim of the study was to demonstrate different MRI and MRA patterns of The vertebrobasilar Dolicoectasia as a respectable cause for neurological symptoms and signs including nerve palsies and posterior fossa infarctions. One hundred patient with neurological symptoms related to the portrait of the vertebrobasilar system were evaluated with MRI and MRA. Patients were referred from the outpatient clinics with retrolabyrinthine Hearing deficit, pulsatile tinnitus. facial spasm, trigeminal neuralgia or vertebrobasilar stroke features. The average age was 59 years with a standard deviation of 12 years. The females represent one third of cases while the males were two thirds. The most common presentation was vertebrobasilar insufficiency [VBI] in thirty percent, followed by facial spasm and pulsatile tinnitus in twenty three percent, trigeminal neuralgia in twenty one percent, cerebellar infarctions in seventeen percent and brain stem stroke in nine percent. Basilar and vertebral arteries were more commonly involved, while Labyrinthine artery was the least involved vessel The commonly missed vertebrobasilar Dolicoectasia should be considered as a respectable cause for neurological symptoms and signs including nerve palsies and posterior fossa infarctions. MRI and MRA are the modalities of choice to demonstrate the wide range of vascular changes occurred with Dolicoectasia and also their effect as nerve compression or vascular occlusions by embolization or thrombosis. The most common nerves to be involved is the trigeminal, acoustic and facial ones. If the radiologist does not consider this pathological entity as a cause for cranial nerve compression palsy, false negative results could occur. Vertebrobasilar Dolicoectasia [VBD] is considered uncommon, but this consideration should be changed in searching for causes of posterior fossa neurological symptoms especially in nerve compression or strokes

value of color doppler in the evaluation of suspected appendicitis

Acute appendicitis is the commonest surgical abdominal emergency. The optimal management of acute appendicitis is predicated on early diagnosis and prompt operative intervention. The early clinical diagnosis of this condition remains difficult, as approximately one third of patients with the disease have an uncertain preoperative diagnosis. This may lead to a delay in surgery or to unnecessary laparoscopy. The consequences of missed or delayed diagnosis include perforation, abscess formation and peritonitis. These complications can result in longer hospitalization and increased risk of infertility in female patients. Another challenge in the management of acute right lower quadrant pain is to reduce the frequency of negative laparoscopies. The percentage of normal appendices at laparotomy in various studies has ranged as high as 25% .Current imaging modalities utilized in the assessment of suspected appendicitis include radiography, sonography and CT. The principal imaging technique utilized at many institutions is sonography. Sonographic diagnosis of the inflamed appendix is well known, but what color Doppler can add in its accuracy. Sonography can not alone diagnose non-obstructive appendicitis, can color Doppler help in this situation. What is the relation between the pattern of vascularity and the degree of inflammation? To the best of our knowledge no detectable studies in the literature about the color Doppler features of different inflammatory types and degrees of appendicitis. We performed color Doppler imaging in patients with suspected appendicitis to characterize its ability to differentiate acute obstructive from non obstructive appendicitis, appendiceal perforation from appendiceal abscesses. Fifty patients with surgically proven appendicitis were selected for the results out of eighty nine patients examined by color Doppler to assess the vascularity of the inflamed appendix. Vascularity was considered diffuse when the vessels were evenly distributed around the walls of the inflamed appendix, while it was considered patchy in uneven increased vascularity. Fifty patients with surgically proven appendicitis were selected for the results out of eighty nine patients examined by color Doppler. The patients were 37 female and 13 male with average age of 23 years. Patients with appendicitis were divided into five groups. Group A include twenty one cases with obstructed non perforated appendicitis, group B include six patients with non-Obstructed non perforated appendicitis, group C include seven patients with Impending perforation, group D include ten patients with perforated appendicitis and group E include six patients with appendicular abscess. Color Doppler sonography showed appendicular hyper-vascularity in 18 of the 21 patients with Obstructed non-perforating appendicitis group [A] and in 4 of the 10 patients with perforating appendicitis group [D] While in 2 of the 6 patients with appendicular abscess group [E] The hyper - vascularity was patchy in 14 of group [A]and in 5 of group [C]and in 3 of group D. Diffuse hyper-vascularity was noted in four cases with group [A]. while in one case out of 10 in group [D]and no detectable diffuse hyper- vascularity in appendicular abscess cases, while all cases in group [B] had diffuse even hyper-vascularity. Color Doppler can show the type of vascularity of the inflamed appendix and so the level of its

Role of multislice ct and local contrast in diagnosis and characterization of choanal atresia

Choanal atresia is defined as a pathological closure or absence of the posterior nasal choana, it may be unilateral or bilateral It is the most common nasal abnormality in the new born. In case of bilateral choanal atresia, when the infant has his mouth closed, he. can not inspire and becomes cyanotic. Unilateral atresia is usually discovered at 1 to 2 year old child with unilateral copious mucoid rhinorrhea. Computerized tomography is now the method of choice in the evaluation of congenital choanal atresia. Both coronal and axial cuts are needed in determining whether the disease is unilateral or bilateral, and the approximate thickness of the bone. The knowledge of abnormal anatomy is vital in preoperative planning and help with choice of surgical technique. This study aims to illustrate the potential value of multislice CT with nasal local contrast administration in the diagnosis and characterization of the detailed anatomical abnormality of Choanal atresia without the need for direct coronal CT. Seventeen patients were examined [ten females and seven males]. The youngest was 1 day neonate and the oldest was 6 year old child. All patients were referred for evaluation of nasal obstruction and to exclude clinically suspected Choanal atresia. The child or neonate was prepared in supine position and axial multislice CT study was done. The examinations were done with a pilch of 2.5 mm, reconstruction of 1.25 mm interval and no gantry tilt. Three drops of half diluted non-ionic contrast was dropped into each nostril just prior to the examination. Reconstruction in saggittal and oblique coronal was done till the posterior choana were seen clearly in all patients with different reformatting angles. The maxillary spines were considered as a mark to the inferior margin of the posterior choana. Posteroinferior vomer width was measured. It was considered thickened when it exceeds 5.5 mm. [12]. All surgical cases were managed by using fibrop

CT and MRI of the external auditory canal

The most dangerous inflammation of the external ear is malignant otitis externa. Pseudomonasaeruginosa is the commonest organism, however early diagnosis requires culture of the ear secretions beforeosteomylitis occurs. Radiological diagnosis can help in the diagnosis and estimation of the prognosis. Thirty three patients with positive radiological findings were chosen, all were referred from theoutpatient clinic complaining of ear discharge, otalgia or swelling .The cases had some difficulties in their clinicaldiagnosis or uncertain differential diagnosis. They were twenty two males and eleven females. The average agewas forty seven years old . The oldest patient was eighty five, while the youngest was nine years old. MRI and CTwere done for all patients beside the culture of ear discharge. History of long term DM or immune-suppressedconditions was registered. The aim of this work is to illustrate the role of CT and MRI in delineation of differentpathological entities of the external ear, with special emphasis on the evaluation of necrotizing otitis externa andits early radiological signs, complications and differential diagnosis.The patients were divided into four groups .The first one contains sixteen cases with malignant otitisexterna, the second one was middle ear infection with mastoiditis and external ear involvement, it includes sixpatients. The third group is three patients with external ear cholesteatoma. The fourth group contains eightpatients with different rarer external ear pathology for the first and largest group Positive findings in all CT andMRI studies. Laboratory studies of these radiologically proven cases reveal positive fungal infection in ten casesand negative cultures in the remaining six.The cases of malignant otitis externa show erosions in the external auditory canal in all patients, involvement ofthe petrous bone and middle ear in half of the cases while seven patients show skull base and or tempomandibularjoint osteomylitis. Facial nerve canal involvement occurs in six patients, while carotid canal was only involved inonly tow patients. We conclude that CT and MRI are the best imaging modalities for evaluating the extent and characterof bony and soft-tissue abnormalities of the EAC. CT scan is more helpful in bony evaluations, while MRI is morehelpful in evaluating the soft tissue involvement. Radiological imaging including combined CT scan and MRI is ofgreat value in early diagnosis of malignant otitis externa [before involvement of-the facial nerve] and so it candecrease the high mortality rate associated with late diagnosis of that aggressive infection

Facial nerve MRI enhancement in various pathological entities

The facial nerve serves motor, sensory and autonomic functions. Anatomical variations exist in length or thickness of all intra-petrous segments as frequent dehiscence that can lead to false diagnosis. Enhancement of facial nerve could be noted in normal and abnormal cases, the familiarity of radiologists for normal enhancement of different parts of the nerve can help to detect pathological conditions as Bell's palsy, tumors and other diseases. The aim of the study was to demonstrate the difference in enhancement patterns of facial nerve segments in normal individuals and various pathological conditions. The MRI findings of 156 patients were evaluated. All patients were examined on the 1.5 Tesla MR Unit using head coil. Contrast material was injected intravenously using a bolus of 0.1 mmol/kg body weight. The evaluation of contrast enhancement was mainly based on visual inspection and comparison between pre- and post-contrast images at the same planes. The facial nerve segment was considered enhancing when there were increased signals of that segment compared to the pre-contrast images. The intensity, thickness and right-left symmetry of enhancement were assessed in each segment. The studied cases were divided into seven groups including normal cases in seventy-eight, acute Bell's palsy in twenty six cases, Necrotizing External Otitis in nine cases, Congenital disorders in eight cases, Tumors in nineteen cases and Petrous apicitis, Cholesteatoma, Chronic Otitis Media in fourteen cases and multiple sclerosis in two cases. This study concluded that the transverse tympanic and proximal vertical mastoid segment may enhance in normal population, due to the presence of a rich perineural venous plexus surrounding the nerve in the fallopian canal. The study suggests three criteria for pathological enhancement: enhancement outside the facial canal; extension of enhancement to the eighth nerve; and intense enhancement in the labyrinthine and/or mastoid segments. We concluded that contrast enhancement of the distal intrameatal and a labyrinthine segment is specific for facial nerve palsy. The disappearance of facial nerve enhancement was found to be related to improvement in facial nerve function during recovery from Bell's palsy. The intensity of contrast enhancement did not correspond to the severity or duration

value of CT scan in stapes surgery for otosclerosis

The availability of HRCT with it is detailed anatomical visualization of fine structure of middle and inner ears makes it the best modality in the diagnosis of otosclerosis. Twenty patients were examined and operated for otosclerosis, the females were more involved and 75% of cases had bilateral involvements, with positive family history supporting its inherted back ground. to evaluate the accuracy of HRCT in preoperative evaluation of otosclerosis. Result and CT scan visualize otospongiosis as illdefined hypodensities at oval window, lateral labyrinthine wall and as around the cochlear turns. The disease is in pure sclerotic phase, underestimation is suspected. The volume average artifact decrease the ability in detecting thickened footplate or stapes crus. Postoperative evaluation by CT scan explains the causes of surgical failures of disease recurrence