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 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