Management of aortobronchial fistula following coarctation repair.

Aortobronchial fistula is a rare complication following thoracic aortic operations and is invariably fatal if not promptly diagnosed and repaired. Direct prosthetic repair carries a risk of graft repair sepsis and fistula recurrence. We describe two cases presenting with aortobronchial fistula following coarctation repair which were successfully treated by different surgical approaches.     

Intracranial glossopharyngeal neurinomas. Report of two cases with special emphasis on computed tomography and magnetic resonance imaging findings

Two patients with intracranial glossopharyngeal neurinoma are described. In both patients, neurologic signs and findings of conventional radiologic and computed tomography examinations suggested a diagnosis of acoustic neurinoma. Magnetic resonance imaging, however, definitely indicated that the mass had actually arisen from the lower cranial nerves. This was confirmed at operation. The superb sensitivity and specificity of magnetic resonance imaging in the diagnosis of posterior fossa extraaxial mass are emphasized.     

Imaging diagnosis of esophageal carcinoma by computed tomography and magnetic resonance imaging

The staging diagnosis of esophageal carcinoma is important to determine therapeutic modalities and to predict prognosis. The current status of imaging diagnosis of tumor invasion to the adjacent organs and lymph node metastasis is described. The diagnostic criteria used to determine tumor invasion to the adjacent or gans by computed tomography (CT) and magnetic resonance imaging(MRI) are displacement and compression deformity of the tracheobronchial tree and obliteration of the periaortic fat plane over more than 90 degrees of the aortic circumference. Detection of the fat plane between the esophagus and the aorta supported by density profile analyzing software on CT may enable the diagnosis of invasion. Cine-MRI imaging is also useful to obtain dynamic information on the tumor and aorta. Tumor invasion to the aortic wall can be excluded when a low-intensity stripe is recognized between the tumor and the aortic wall. Although the criterion for lymph node metastasis on CT is 10 mm or more in long transverse diameter, the diagnostic accuracy is poor. The accuracy improves when imaging patterns such as heterogeneous internal structures in the enhanced lymph nodes and/or hyperenhancement in the lymph nodes in the early phase by dynamic study are added to the diagnostic criteria. However, small metastatic lymph node remain undetected and it is difficult to diagnose negative lymph node metastasis properly on CT and MRI. It is important to have full knowledge of the advantages and limitations of each imaging modality and to obtain objective information form them.     

Comparative study of brain abscess by computed tomography and magnetic resonance imaging: report of two cases

Two cases of cerebral abscess with different presentations are reported. The source of the abscess remained obscure in one case while in the other arose from infection of the right frontal sinus. While in one case a magnetic resonance image was obtained preoperatively, both cases underwent parallel monitoring in the postsurgery period by computed tomography and magnetic resonance imaging. The relative merits of these two imaging techniques in the diagnosis and monitoring of such lesions are discussed, and the literature is reviewed.     

Comparison of computed tomography and magnetic resonance imaging in the diagnosis of parotid tumors

OBJECTIVE: The role of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of parotid tumors was investigated. METHODS: Forty patients with the clinical suspicion of a parotid mass underwent both CT and MRI of the parotid region. Two radiologists independently assessed the CT and MRI results with respect to tumor localization, tumor margin characteristics, and infiltration of surrounding tissue. Histopathologic specimens were obtained in all cases and correlated with the radiologic findings. RESULTS: The sensitivity and specificity of CT and MRI were nearly the same for tumor location, tumor margin, and tumor infiltration. CONCLUSION: The 2 imaging techniques provided the same information with respect to the presurgical planning and contribute to the diagnosis and therapy planning of parotid tumors.     

Comparison of computed tomographic scanning and magnetic resonance imaging in the diagnosis of trigeminal schwannoma. Report of four cases

Four cases of trigeminal schwannoma with different clinical presentations are reported. Two patients had root-type tumors and two ganglion-type tumors. Computed tomography demonstrated the mass in each case, but extension of the tumor into Meckel's cave, displaced but uninvolved seventh and eighth cranial nerves, extension of the tumor into the orbit or into the infratemporal fossa, and other anatomical details were far more clearly shown by magnetic resonance imaging, which provided confirmation of the mass lesions in the base of the brain and within the posterior fossa.     

Vertebral arteriovenous fistula following anterior cervical spine surgery. Report of two cases

Fistulous communication between the vertebral artery and its surrounding venous plexus is rare. Two cases of vertebral arteriovenous fistula following anterior cervical spine surgery are reported. The anatomic relationships of the vertebral vessels, the radiographic findings, and the various therapeutic approaches to these lesions are discussed.     

Preoperative imaging of aortic aneurysms. Conventional and digital subtraction angiography, computed tomography scanning, and magnetic resonance imaging

Aneurysm imaging is important in deciding on the timing of and operative approach for aneurysmorrhaphy. Various noninvasive and invasive imaging techniques are available for the anatomic definition of abdominal aortic aneurysms, involvement of adjacent structures, and intra-abdominal pathology. Careful preoperative evaluation can avert hemorrhagic, embolic, and ischemic complications of elective aneurysm repair.     

Contrast enhanced computed tomography and magnetic resonance imaging in the diagnosis of recurrent disc herniation

Summary A positive result of re-operation in patients with recurrent symptoms after lumbar disc surgery is likely only if a new disc herniation is present. An improved ability to differentiate between recurrent disc herniation and scar tissue by contrast enhanced CT and MRI is suggested in earlier studies.In a prospective study 29 patients were selected for operation for suspected recurrent disc herniation. The inclusion of the patients was based on clinical symptoms and signs and myelography or non-enhanced CT. All patients were examined by CT and MRI both with and without intravenous contrast pre-operatively. The examinations were evaluated blind on a five point scale and statistical analysed by a regret function.Intravenous contrast improved the diagnostic power of both CT and MRI. MRI was superior to CT in both non-enhanced and enhanced examinations. MRI with intravenous contrast enhancement is proposed as the primary examination in patients with suspected recurrent disc herniation.     

Roles of radiograph, magnetic resonance imaging, threedimensional computed tomography in early diagnosis of femoro-acetabular impingement in 17 cases

Objective: To evaluate the roles of radiograph, magnetic resonance imaging (MRI), three-dimensional computed tomography (3-D CT) in early diagnosis of femoro-acetabular impingement (FAI) in 17 cases. Methods: Plain radiographs of the pelvis, 3-D CT, and MRI of the hip were made on 17 patients with groin pain, which was worse with prolonged sitting (i.e. hip flexion). There was no history of trauma or childhood hip disorders in the patients who did not complain of any other joint problems or neurologic symptoms. All patients had positive anterior or posterior impingement test. Plain radiographs included an antero-posterior (AP) view of the hip and a cross table lateral view with slight internal rotation of the hip. CT scan was performed with the Lightspeed 16 row spiral (General Electric Company, USA) at 1.25 mm slice reconstruction. MRI scan was performed on the Siemens Avanto (Siemens Company, Germany)1.5T supraconducfion magnetic resonance meter. The CT and MRI scans were taken from 1 cm above the acetabulum to the lesser trochanter in 5 series. Results: The plain radiographs of the pelvis showed that among the 17 patients, 12 (70.59%) had "Cam" change of the femoral head, 6 (35.29%) had positive "cross-over" sign, and 17 (100%) had positive "Pincer" change of the acetabulum. The 16 row spiral CT noncontrast enhanced scan and 3-D reconstruction could discover minus femoral offset and ossification and osteophyte of the acetabulum labrum in all the 17 cases (100%). The MRI noncontrast enhanced scan could discover more fluid in the hip joint in 15 cases (88.33%), subchondral ossification in 3 cases (17.6%), and labium tears in 3 cases (17.6%). Conclusions: Plain radiographs can provide the initial mainstay for the diagnosis of FAI, 3-D CT can tell us the femoral offset, while MRI can show labrum tears in the very early stage of FAI. Basically, X-ray examination is enough for the early diagnosis of FAI, but 3-D CT and MRI may be useful for the treatment.     

Differential diagnosis and staging of urological tumors by magnetic resonance imaging compared with computed tomography

Magnetic resonance imaging (MRI) was performed on 49 urological tumors (11 renal cell carcinomas, 3 renal pelvic cancers, 2 renal angiomyolipomas, 1 renal leiomyosarcoma, 1 large renal cyst, 4 adrenal tumors, 11 bladder cancers, 2 bone metastasis from bladder cancer, 10 prostatic cancers, 1 prostatic sarcoma, 1 urethral cancer, 1 penile cancer and 1 perivesical granuloma) since October 1985 to September 1986. MRI was performed using a Signa (G.E.) with a 1.5T superconductive magnet and 3 images, including T1 weighted image, T2 weighted image, and proton density image, were obtained. In conclusion MRI is a noninvasive examination and gives more information than computed tomography despite its high cost. In renal cell carcinoma, the chemical shift in MRI and clear visualization of tumor thrombus enable accurate staging. Differential diagnosis from other renal mass lesions may be possible by the T2 weighted image. In adrenal disease, most of the adrenal masses can be differentiated, but in some cases it is impossible. In bladder cancer, wall invasion of tumor may be evaluated in T2 weighted image, and MRI is suitable for staging of locally advanced tumor. In prostatic cancer, visualization of periprostatic plexus and differentiation between internal and external gland may enable local staging and identification of low stage tumors.     

Magnetic resonance imaging in myelocystoceles. Report of two cases

Two cases of terminal myelocystocele, a rare localized cystic dilatation of the caudal spinal central canal, are reviewed. Magnetic resonance imaging is a useful diagnostic tool for its evaluation. Terminal myelocystocele consists of the following: a myelocystocele which contains a "trumpet-like" flaring of the distal spinal cord central canal and thus is partially lined by ependymal tissue; a meningocele or dilated subarachnoid space located around the myelocystocele, which bulges into the subcutaneous region; and fibrolipomatous tissue surrounding the two cysts. This condition is usually associated with abnormalities of the vertebral column and sacrum as well as compression of the spinal cord and meningocele by a fibrous band. There is a possible relationship of the myelocystocele to teratogens such as loperamide HCl and retinoic acid, although the exact etiology of this entity is not known.     

Postoperative magnetic resonance imaging artifacts. Report of three cases

Artifacts are occasionally encountered on magnetic resonance imaging after operation. These may be due to minute metallic particles from neurosurgical instruments. Particles not detectable on plain x-ray films or computerized tomography scans may cause local change of magnetic resonance activity, resulting in a deceptive magnetic resonance appearance. Three illustrative case reports are presented.     

Carotid-cavernous fistula following percutaneous retrogasserian procedures. Report of two cases.

Carotid arterial puncture during percutaneous retrogasserian procedures is a common but usually harmless complication. Strokes, resulting presumably from carotid artery thrombosis, have been reported previously following percutaneous retrogasserian coagulation. The authors report two cases of carotid-cavernous fistula, one following percutaneous radiofrequency rhizotomy and the other after percutaneous retrogasserian block. The latter patient had an anomaully by intracavernous injection of isobutyl-2 cyanoacrylate, using intra-arterial balloon flotation catheters. Carotid-cavernous fistula is a potentially serious complication of such procedures, and may be more common than realized since small fistulas may close spontaneously.     

Role of computeric tomography and magnetic resonance imaging in diagnosis of inflammatory diseases of sacro-ileal joint

Sensitivity of computeric tomography (CT) and magnetic resonance imaging (MRI) for sacroileitis diagnosis was studied, optimal for MRI investigation was established. In 31 patients, owing obvious clinical signs of inflammatory sacroileitis (at average more than 5 mo duration of a low back pain) MRI of sacroiliac joint was conducted in a T1, T2 FS, 2D T2 FLASH regimes and after intravenous infusion of a contrast substance (gadolinium) - in a T1 FS regime, using system, owing a 1,5 T magnetic field intensity. The data obtained were compared with results of CT. Sacroileitis signs were revealed in 27 patients - according to CT data, and in 22 - MRI. CT have demonstrated as a more sensitive method of the bone erosion and sclerosis diagnosis, than MRI. MRI is more sensitive while revealing an active inflammatory process in the bone and joint space. While T1 FS application no additional information for sacroileitis diagnosis was obtained.     

Glial cyst of the pineal gland with characteristic computed tomography, magnetic resonance imaging, and pathological findings: report of two cases.

Two cases of glial cyst of the pineal gland are documented. Preoperative computed tomography and magnetic resonance imaging revealed cystic lesions of the pineal region with contrast enhancement of the walls, suggesting neoplastic lesions rather than true cysts. However, the histopathological examination of the resected specimens revealed the presence of glial tissue and normal structure of pineal gland and capsule, characteristics that were consistent with those of glial cysts of the pineal gland. Headache and visual disturbance were resolved after total removal of the cysts.     

A comparison between magnetic resonance imaging and computed tomography for stereotactic coordinate determination.

The spatial accuracy of magnetic resonance imaging (MRI) has not been established for stereotactic surgery. Magnetic susceptibility artifacts may lead to anatomical distortion and inaccurate stereotactic MRI coordinates, especially when targets are in regions of the brain out of the center of the magnetic field. MRI-guided stereotactic localization, however, provides better multiplanar target resolution than is available with computed tomographic (CT) scanning. Therefore, we compared the accuracy of stereotactic coordinates determined by MRI and CT studies in 41 patients (53 targets). Coordinates were measured in each plane and as vector distances between the target and the center of the stereotactic frame on axial or coronal MRI studies. Absolute axial plane MRI and CT distances varied an average of 2.13 +/- 1.59 mm. The mean difference in measurements in the X (left-right) dimension was 1.19 mm and 1.55 mm in the Y (anterior-posterior) dimension. Central targets (located less than 2 cm from the frame center) had a mean MRI-CT difference of 2.09 +/- 1.79 mm; peripheral targets (greater than 2 cm from the frame center) differed by 2.17 +/- 1.3 mm. The voxel volumes were calculated for all compared images. Although differences between the physical properties of data acquisition with each imaging modality could explain the observed CT-MRI discrepancies, a 1-pixel difference in target selection could account totally for all the variance observed. MRI field strength (0.5 vs. 1.5 T) did not correlate with coordinate determination accuracy. We conclude that MRI-guided stereotactic localization can be used with confidence for most diagnostic, functional, and therapeutic stereotactic procedures.