The effect of venous anatomy on the morphology of multiple sclerosis lesions: a susceptibility-weighted imaging study.

AIM: To investigate the cause of morphology in non-ovoid multiple sclerosis (MS) lesions lacking a radial course and typical shape. MATERIALS AND METHODS: Non-ovoid atypical lesions without perpendicular extensions to the ventricle were investigated in 95 MS patients by retrospective examination of T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. The relationship between the morphology of these atypical lesions detected in 38 patients and central vein anatomy was examined using susceptibility-weighted imaging (SWI). RESULTS: A central venous structure was observed in 107 (65.6%) of 163 atypical lesions in 38 patients. The distribution of atypical lesions grouped by their shape was as follows: (1) V- or Y-shaped lesions (n=27, 48.6%) were observed where veins bifurcated; (2) crescent-shaped lesions (n=9, 8.4%) were observed where veins formed an arc; (3) patchy lesions comprised 48.6% (n=52) of the atypical lesions and involved multiple medullary veins or medullary veins showing a "caput medusae" distribution; (4) ovoid lesions with a non-radial course (n=19, 17.7%) were generally observed where medullary veins converged to form internal cerebral vein branches. CONCLUSION: Unlike typical MS plaques, non-ovoid atypical lesions make the differential diagnosis of MS challenging. Demonstration of the relationship between venous anatomy and lesion morphology in atypical lesions using SWI will aid in the differential diagnosis.

An abdominal muscular fold mimicking tumour.

Mass-like lesions and anatomical variations sometimes create challenges for diagnosis in both clinical and radiology practice. We present a "pseudomass" originating from the right abdominal wall in a 75-year-old patient with invasive ductal carcinoma of the breast. Age-related structural changes in the abdominal wall, as well as anatomical variations, should be kept in mind in order to establish the correct radiological diagnosis and to avoid unnecessary procedures.

A case of brain abscess due to Entamoeba species, Eikenella corrodens and Prevotella species.

We report a case of brain abscess due to multiple pathogens including Entamoeba species, Eikenella corrodens and Prevotella species. Patient had odontogenic infection without any site of amoebic infestation. Complete recovery was achieved with surgical treatment and antimicrobial therapy.

A case of schizencephaly presenting with unilateral cryptophthalmos.

We describe an unusual case of schizencephaly associated with unilateral orbital meningoencephalocele, anophthalmos, orbital soft mass, cryptophthalmos and partial agenesis of corpus callosum, along with ectopic kidney and thumb anomaly.

Contrast medium-enhanced MRI findings and changes over time in stage I tuberculous meningitis.

AIM: To demonstrate the detailed imaging characteristics of early tuberculous meningitis (TBM) and changes over time on standard gadolinium-enhanced, T1-weighted magnetic resonance imaging (MRI) images. MATERIALS AND METHODS: Contrast-enhanced, T1-weighted, spin-echo MRI images of 26 patients with early TBM were evaluated retrospectively. Meningeal enhancement characteristics were categorized according to distribution and pattern as diffuse, focal, linear, nodular, and mixed. RESULTS: We found that 35% of patients had diffuse meningeal enhancement and 65% of cases had focal meningeal enhancement. There was a predilection for focal meningeal enhancement in basal pial areas, the interpeduncular fossa being the most common. In six patients with diffuse meningeal enhancement admitted to hospital relatively early after the onset of symptoms, the type of meningeal enhancement later changed to the focal form. CONCLUSION: Reactive diffuse meningeal enhancement occurs in the early period of TBM on contrast medium-enhanced T1-weighted MR images, but later becomes limited to basal areas.

The place of computed tomography as a guidance modality in percutaneous nephrostomy: analysis of a 10-year single-center experience.

BACKGROUND: Percutaneous nephrostomy (PCN) has been established as an effective technique for urinary decompression or diversion. This procedure may be performed with the guidance of fluoroscopy, ultrasonography, a combination of fluoroscopy and ultrasonography, computed tomography (CT), or magnetic resonance imaging. PURPOSE: To retrospectively review experience with CT-guided PCN over a 10-year period in a single center. MATERIAL AND METHODS: All CT-guided PCN procedures performed in adults at our institution between 1995 and 2005 were evaluated. In 882 patients, 1113 nephrostomy catheters were inserted. Interventional radiologists or radiology residents under direct attending supervision inserted all catheters. During the PCN procedure, bleeding, sepsis, and injuries to adjacent organs were regarded as major complications. Clinical events requiring nominal therapy with no sequelae were regarded as minor complications. RESULTS: PCN procedures were performed via 1-3 punctures in patients with grades 0-1 and 2 hydronephrosis, and via 1-2 punctures in patients with grade 3 hydronephrosis. They were carried out with a procedure time ranging from 9 to 26 min. All PCNs were considered as technically successful, and no major complications were observed. There were minor complications including transient macroscopic hematuria (28.6%, 19.9%, and 4.9% in patients with hydronephrosis grades 0-1, 2, and 3, respectively) and perirenal hematomas in a total of eight patients. No patient required additional intervention secondary to complications of the PCN procedure. CONCLUSION: CT-guided PCN is an efficient and safe procedure with major and minor complication rates below the accepted thresholds. It can be used for the management of patients requiring nephrostomy insertion in inpatient settings, and might be a preferable procedure in patients with minimal or no dilatation of the renal pelvis.

Nitric oxide synthase inhibition attenuates vasoactive response to spinal cord stimulation in an experimental cerebral vasospasm model.

BACKGROUND: The basic mechanism of delayed cerebral vasospasm following subarachnoid haemorrhage (SAH) has been intensively investigated. It is thought that nitric oxide (NO) is a basic mediator of the cerebral vasodilator mechanism. Previous clinical and experimental studies have shown a cerebral vasodilator effect of high cervical spinal cord stimulation (SCS) however, the mechanism of this effect is still controversial. We investigated the contribution of the vasodilator effect of NO to this mechanism in an experimental SAH model using rabbits. METHOD: Four experimental groups, were designated: Group 1. Cerebral blood flow (CBF) was evaluated by transcranial Doppler ultrasonography (TDU) in 8 rabbits. Group 2. In 4 animals, intracisternal saline injection and cervical epidural electrode placement without SCS were performed before TDU. Group 3. TDU was performed before and after SCS on the fourth day of SAH in 8 rabbits. Group 4. In 8 animals, N-Nitro-L-Arginine Methyl Esther (L-NAME) was administered intracisternally on the fourth day of SAH, at a dose of 0.6 mg/kg, 45 minutes before SCS. CBF parameters, obtained via measurements or calculations from TDU data, were compared. FINDINGS: The occurrence of vasospasm after SAH was demonstrated with significant changes in TDU parameters (high peak systolic velocity and positive values of the degree of stenosis). In all SAH animals, SCS resulted in significant vasodilation. Even after the injection of L-NAME, SCS still had a significant vasodilatory effect in SAH animals, but there was also a significant difference in CBF parameters in the SCS-only group when compared with the L-NAME treatment before SCS group. INTERPRETATION: The mechanism of the cerebral vasodilatory effect of SCS remains controversial. Our results revealed the contribution of a neurohumoral effect which can be partially prevented by use of an NO synthase inhibitor.

The therapeutic effect of continuous intracisternal L-Arginine infusion on experimental cerebral vasospasm.

BACKGROUND: Recent studies on the pathogenesis of cerebral vasospasm following subarachnoid haemorrhage (SAH) suggest a breakdown of the balance between the vasoconstrictor and vasodilator systems. A shortage of a major cerebral vasodilator, nitric oxide (NO), has been accused of causing this breakdown. We investigated the effect of continuous intracisternal infusion of a NO precursor, L-Arginine, in a rabbit SAH model. METHOD: Three experimental groups were designated: Group 1--Cerebral blood flow (CBF) data was obtained via transorbital Doppler ultrasonography (TDU) in 8 normal rabbits. Group 2--Intracisternal catheter placement and TDU study during saline infusion were performed in 8 animals at the 4th day of SAH, Group 3--SAH occurred in 8 animals. 4 days later, L-Arginine was infused intracisternally for 1 hour, while TDU was performed before and during infusion. CBF parameters which were obtained via TDU measurement or calculations, were compared. FINDINGS: The results of TDU revealed significant vasospasm in all SAH animals, as well as resolution of vasospasm with L-Arginine infusion. After 20 minutes of infusion, a steady and sustained vasodilation was obtained in the third group. The analysis of CBF data revealed a significant difference in SAH values, and no difference in control animals. INTERPRETATION: Our results support the contribution of the "NO shortage" concept in the pathogenesis of cerebral vasospasm and overconsumption of L-Arginine during the post-SAH period may cause this shortage. L-Arginine treatment may be useful for the prophylaxis and treatment of cerebral vasospasm. The intracisternal infusion method can eliminate the short action time disadvantage of L-Arginine.