Brain MR post-gadolinium contrast in multiple sclerosis: the role of magnetization transfer and image subtraction in detecting more enhancing lesions.

Our purpose was to evaluate the role of magnetization transfer and image subtraction in detecting more enhancing lesions in brain MR imaging of patients with multiple sclerosis (MS). Thirty-one MS patients underwent MR imaging of the brain with T1-weighted spin echo sequences without and with magnetization transfer (MT) using a 1.5 T imager. Both sequences were acquired before and after intravenous injection of a paramagnetic contrast agent. Subtraction images in T1-weighted sequences were obtained by subtracting the pre-contrast images from the post-contrast ones. A significant difference was found between the numbers of enhanced areas in post-gadolinium T1-weighted images without and with MT (p=0.020). The post-gadolinium T1-weighted images with MT allowed the detection of an increased (13) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. A significant difference was also found between the numbers of enhanced areas in post-gadolinium T1-weighted images without MT and subtraction images without MT (p=0.020). The subtraction images without MT allowed the detection of an increased (10) number of enhancing lesions compared with post-gadolinium T1-weighted images without MT. Magnetization transfer contrast and subtraction techniques appear to be the simplest and least time-consuming applications to improve the conspicuity and detection of contrast-enhancing lesions in patients with MS.

Diagnostic efficacy and safety of MRI of the liver with superparamagnetic iron oxide particles (SH U 555 A).

The purpose of this study was to evaluate the diagnostic efficacy and safety of an intravenous injection of magnetic resonance imaging (MRI) contrast agent, SH U 555 A, in adult patients with known focal liver lesions. Pre- and post-contrast image sets were obtained in 19 patients after injection of SH U 555 A as a part of a phase III clinical trial (patients <60 kg body weight received 0.9 mL and patients >60 kg received 1.4 mL). Three blinded readers evaluated the post-contrast images. Blood pressure and heart rate were recorded and laboratory tests were performed at baseline, during and immediately after the procedure, and four and 24 hours after the MR procedure. On post-contrast MRI, there was statistically significant improvement in diagnostic confidence, visualization, delineation, and contrast between the lesions and the healthy parenchyma in comparison to precontrast. Twenty more lesions were detected on post-contrast images. The management in six patients (31.7%) was changed after post-contrast imaging. Changes in vital signs and laboratory tests were minimal and did not affect the patients' clinical condition. Only a moderate allergic reaction (diffuse erythematous rash) was recorded. SH U 555 A is an effective and safe contrast agent for MRI of the liver.

MR imaging of tuberculous vertebral osteomyelitis: pictorial review.

Vertebral osteomyelitis is one of the most common manifestations of tuberculosis. Magnetic resonance imaging is considered the main imaging modality for the diagnosis, the demonstration of the extent of the disease, and follow-up studies. Vertebral destruction involving two consecutive levels with sparing of the intervertebral disc, disc herniation into the vertebral body, epidural involvement, and paraspinal abscess are the most common MRI findings suggestive of tuberculous vertebral osteomyelitis.

Imaging of a supernumerary kidney.

A 33-year-old female patient was investigated for a right lower quadrant pain. The investigation, which included an excretory urography and a computed tomography examination, revealed a normal kidney on the right side and another two normal sized, complete kidneys on the left side, which appeared to have a small parenchymal bridge. The patient was treated surgically for a cyst of the right ovary.

Computed tomography-guided fine needle aspiration of peripheral lung opacities. An initial diagnostic procedure?

OBJECTIVE: To evaluate the results of computed tomography (CT)-guided fine needle aspiration (FNA) cytology following negative fiberoptic bronchoscopy and sputum cytology. STUDY DESIGN: Retrospective study of 64 patients who underwent CT-guided needle aspiration of lung opacities over one year. Following a review of the CT studies, patients were selected according to image characteristics of a primary neoplasm and pleural effusion in cases with pleural lesions. The lesions were classified into three categories--intrapulmonary and peripheral pulmonary, pleuropulmonary and pleural--and were localized and aspirated under CT using a fine needle (22-23 gauge) for obtaining cellular material. Lesions diagnosed as benign on FNA cytology were followed by serial CT scans for a period of two years at six-month intervals. RESULTS: Thirty-nine of 64 (61%) lesions were diagnosed as malignant on FNA cytology and 25 of 64 (39%) as benign. There was one false negative case. There were no serious complications from the procedure. CONCLUSION: FNA under CT guidance may be applied as the initial procedure in the diagnosis of peripheral malignant pulmonary lesions, rendering a high diagnostic yield.

Right adrenal hematoma following hepatectomy.

We present the findings and possible causes in three cases of postoperative adrenal hematomas. In 16 cases of 45 consecutive patients, following segmental right or left lobe hepatectomy, CT was performed in order to evaluate possible fluid collection or other complications. In all cases imaging findings and a correlation with preoperative CT scans were done. Follow up CT examinations were also reviewed. In three cases solid suprarenal masses with attenuation values consistent with adrenal hematomas were found. Preoperative scans at the same level indicated normal adrenal glands. Follow-up scans revealed the hematoma, stable in size, for up to 12 weeks, although lower attenuation values were evident. Right adrenal hematoma is a possible postoperative complication following hepatectomy; if it remains stable in size, it can be left alone.

Large lipoma of the vulva.

Vulvar lipoma is a rare entity. A 52-year-old woman presented with a large mass arising in the right major labium. CT scan revealed that the mass contained adipose tissue. During operation a lipomatous tumor was found which at histologic examination proved to be a lipoma.

Horseshoe kidney associated with anomalous inferior vena cava.

Horseshoe kidney associated with anomalous inferior vena cava is a rare congenital anomaly. Radiological demonstration of this combined anomaly is also uncommon, with only two cases of preisthmic inferior vena cava with horseshoe kidney in the imaging literature. We report a case of simultaneous horseshoe kidney and inferior vena cava lying anterior to the right renal moiety diagnosed by ultrasound and computed tomography.

Retroperitoneal mucinous cystadenoma.

A case of retroperitoneal mucinous cystadenoma histologically confirmed in a 21-year-old woman is reported. Although ultrasound, CT and MR detected the tumor, a preoperative diagnosis could not be established by imaging methods. The cystic tumor was removed and microscopic examination revealed a mucinous cystadenoma. Mullerian mesothelial metaplasia of peritoneal invagination into the retroperitoneal space is the most likely explanation for the histogenesis of these tumors.

Posttraumatic spinal cord lesions without skeletal or discal and ligamentous abnormalities: the role of MR imaging.

The thoracic spine is different from other mobile segments of the spine because of the presence of ribs and their articulations. The rib cage makes the thoracic spine much more stable and, during trauma, provides additional strength and energy-absorbing capacity. This leads to the conclusion that severe trauma is required to damage the thoracic spine, and the skeletal injury is usually evident on radiographs. A spontaneous reducible vertebral luxation (dislocation) is not easy to identify, even with magnetic resonance (MR) imaging. Subtle changes in thoracic spine osseous injuries are not seen on radiographs but may be demonstrated on computed tomography (CT) scans. MR imaging can also demonstrate the posterior ligamentous lesions. In this study, we present three cases of thoracic spinal cord changes without spinal fracture and one disk herniation (degenerative chronic disease). These patients had a permanent neurologic deficit (complete paraplegia); plain radiographs and CT scans showed nothing abnormal. MR imaging showed lesions in the thoracic spinal cord and, in one case, a posttraumatic disk herniation. In cases of post-traumatic cord lesions, MR imaging provides diagnostic information that appears to exceed other imaging modalities. The existence of a neurologic deficit indicates MR as the first examination in cases of traumatic spinal lesions.

Paraganglioma of the cauda equina: a case presenting features of increased intracranial pressure.

Paragangliomas are benign tumors arising from the heterotopic sympathetic ganglion. They occur more often in the carotid body, glomus jugulare, mediastinum, and paraaortic region; central nervous system locations include the petrous ridge, pineal region, and sella turcica. We report the clinical and imaging features of an unusual case of paraganglioma of the cauda equina. Magnetic resonance imaging (MRI) of the thoracolumbar region should be performed in cases of increased intracranial pressure whenever the head examination does not reveal the exact cause of the problem.

MRI of a giant splenic artery aneurysm.

Aneurysms of the splenic artery larger than 3 cm are very rare. We present the imaging features of a 12 cm, partially thrombosed splenic artery aneurysm. MRI was valuable in establishing the diagnosis.

Monograft reconstruction of all the major aortic arch trunks.

Male aged 56 years, a smoker of 60 cigarettes daily, with multifocal disease, presented with vertigo, headaches, syncopal crises and intermittent claudication in both lower extremities. Angiography revealed pre-occlusive stenosis at the origin of the innominate artery, a significant degree of stenosis at the origin of the left common carotid and occlusion of the left subclavicular artery with steal syndrome as well as injury to the aortoiliac system. Revascularisation of all the branches of the aortic arch concomitantly was achieved with the technically simple monograft method using only one Dacron double velour 8 mm prosthesis, restoring circulation to both the cerebral and upper extremities without postoperative complications. Eight years later the subjective clinical findings have remained unchanged. Angiography revealed good function of the graft and subjectively the patient remains in satisfactory condition.

MRI of nasopharyngeal carcinoma metastatic to the cerebellopontine angle.

In patients with nasopharyngeal carcinoma, intracranial spread may occur via direct extension from the base of the skull or via perineural spread. Perineural spread usually affects branches of the trigeminal nerve. We describe two patients with recurrent nasopharyngeal carcinoma, who presented with a solitary mass in the cerebellopontine angle without associated bony destruction. MRI findings mimicked those of acoustic schwannoma. The imaging findings and possible pathways of spread are discussed.

Evaluation of hydatid disease of the heart with magnetic resonance imaging.

Two patients with cardiac involvement of hydatid disease are presented: one with hydatid cyst of the interventricular septum and pulmonary arteries and the other with multiple pulmonary cysts associated with intracardiac and pericardial cysts. The ability of magnetic resonance imaging (MRI) to provide a global view of cardiac anatomy in any plane with high contrast between flowing blood and soft tissue ensures it an important role in the diagnosis and preoperative assessment of hydatid disease of the heart.

Assessment of liver iron overload by T2-quantitative magnetic resonance imaging: correlation of T2-QMRI measurements with serum ferritin concentration and histologic grading of siderosis.

PURPOSE: To correlate hepatic 1/T2 values obtained by means of a T2-Quantitative MRI (T2-QMRI) technique with three widely applied methods for the evaluation of hemosiderosis, i.e., (a) liver iron concentrations (LFeC) (b) serum ferritin (SF), and (c) histologic grading of siderosis. The impact of coexisting hepatitis was also considered. T2-QMRI measurements were compared with signal intensity (SI) ratio measurements on conventional SE images. MATERIALS AND METHODS: Liver T2 relaxation times were calculated in 40 thalassemic patients, on a 0.5 T magnetic resonance imaging system using a multiple spin-echo sequence with parameters: TR = 2500 ms, TE = 12 ms in 20 symmetrically repeatable echoes. RESULTS: (a) 1/T2 values were well correlated (r = 0.97) with liver iron concentrations, which ranged from 2.32 to 18.0 mg/g dry weight (normal < 1.6 mg/g). (b) 1/T2 values were also correlated with serum ferritin levels (r = 0.84). At various 1/T2 values, serum ferritin levels were higher for the anti-HCV(+) patients than the anti-HCV(-) ones. (c) T2 values corresponding to successive grades of siderosis presented statistically significant differences. (d) SI ratio measurement assigned less statistically significant results, as compared to T2 values. CONCLUSION: T2-QMRI measurement of T2 relaxation time is more accurate than SI ratios in evaluating liver iron overload. It is particularly useful for hemosiderotic patients with coexisting hepatitis since, in this case, serum ferritin is not considered a reliable index of hemosiderosis.

CT and MR of pineal region tumors.

Magnetic Resonance (MR) imaging features of pineal region tumors were analyzed in 14 oncologic cases. The tumors were classified as germ-cell tumors, glial tumors, pineal parenchymal tumors, meningiomas, and cysts. They demonstrated different MR signal characteristics on precontrast scans and nodular or ring type enhancement with occasional central lucencies, except for benign cysts, which have not shown enhancement. MR images were useful in defining the relationship of the tumor to the posterior third ventricle, sylvian aqueduct, vein of Galen, and tentorium. Although CT can demonstrate in more evident fashion displacement of the original pineal calcification as well as tumor calcifications, MR imaging demonstrates different signal characteristics in germinomas and pineoblastomas which can be a useful adjunct in the evaluation and differential diagnosis of these tumors.

MRI features in a malignant glomus jugulare tumour.

Magnetic resonance imaging (MRI) features in a case of malignant glomus jugulare tumour are reported. Chemodectomas are benign in 95 per cent of cases and malignant in five per cent. Only one case report of CT findings in this unusual CP angle tumour with pulmonary metastases has been cited in the literature. It is concluded that MRI can provide useful information about the nature of chemodectomas although it cannot distinguish between benign and malignant tumours, except when regional lymph nodes are involved or when distant metastases exist.

Spinal neurilemmomas and neurofibromas: central dot sign in postgadolinium MRI.

The MR studies of three histologically proven spinal neurilemmomas and neurofibromas were reviewed retrospectively. There were two benign neurilemmomas (schwannomas) and one neurofibroma. The common characteristic of these cases was a central low intensity focus ("dot") seen on postcontrast T1-weighted imaging. The low intensity foci corresponded histologically to a congeries of changes including edema, microcysts, foam cells, hyalinization of blood vessels, old hemorrhage, and dystrophic calcification.