Rosai-Dorfman disease with epidural and spinal bone marrow involvement: magnetic resonance imaging and diffusion-weighted imaging features.

Sinus histiocytosis with massive lymphadenopathy (SHML), or Rosai-Dorfman disease, is a rare histiocytic disorder that typically presents with chronic, self-limiting cervical lymphadenopathy. Although this disease mainly affects histiocytes, there are a few reports of bone marrow infiltration. Diffusion-weighted imaging (DWI) is a promising technology in differentiating between various bone marrow pathologies. We here present conventional magnetic resonance imaging and DWI features of a patient with SHML and bone marrow involvement.

Thin-section diffusion-weighted magnetic resonance imaging of the brain with parallel imaging.

BACKGROUND: Thin-section diffusion-weighted imaging (DWI) is known to improve lesion detectability, with long imaging time as a drawback. Parallel imaging (PI) is a technique that takes advantage of spatial sensitivity information inherent in an array of multiple-receiver surface coils to partially replace time-consuming spatial encoding and reduce imaging time. PURPOSE: To prospectively evaluate a 3-mm-thin-section DWI technique combined with PI by means of qualitative and quantitative measurements. MATERIAL AND METHODS: 30 patients underwent conventional echo-planar (EPI) DWI (5-mm section thickness, 1-mm intersection gap) without parallel imaging, and thin-section EPI-DWI with PI (3-mm section thickness, 0-mm intersection gap) for a b value of 1000 s/mm(2), with an imaging time of 40 and 80 s, respectively. Signal-to-noise ratio (SNR), relative signal intensity (rSI), and apparent diffusion coefficient (ADC) values were measured over a lesion-free cerebral region on both series by two radiologists. A quality score was assigned for each set of images to assess the image quality. When a brain lesion was present, contrast-to-noise ratio (CNR) and corresponding ADC were also measured. Student t-tests were used for statistical analysis. RESULTS: Mean SNR values of the normal brain were 33.61+/-4.35 and 32.98+/-7.19 for conventional and thin-slice DWI (P>0.05), respectively. Relative signal intensities were significantly higher on thin-section DWI (P<0.05). Mean ADCs of the brain obtained by both techniques were comparable (P>0.05). Quality scores and overall lesion CNR were found to be higher in thin-section DWI with parallel imaging. CONCLUSION: A thin-section technique combined with PI improves rSI, CNR, and image quality without compromising SNR and ADC measurements in an acceptable imaging time.

Diffusion-weighted imaging of the spine with a non-carr-purcell-meiboom-gill single-shot fast spin-echo sequence: initial experience.

BACKGROUND AND PURPOSE: To prospectively evaluate the signal-to-noise ratio (SNR) improvement in diffusion-weighted imaging (DWI) of the spine with the use of a newly developed non-Carr-Purcell-Meiboom-Gill (non-CPMG) single-shot fast spin-echo (SS-FSE) sequence and its effect on apparent diffusion coefficient (ADC) measurements. MATERIALS AND METHODS: Twenty-four patients were enrolled after written informed consent. DWI of the spine was obtained with an echo-planar imaging (EPI)-based sequence followed by a non-CPMG SS-FSE technique. SNR and ADC values were measured over a lesion-free vertebral corpus. A quality score was assigned for each set of images to assess the image quality. When a spinal lesion was present, contrast-to-noise ratio (CNR) and ADC were also measured. Student t tests were used for statistical analysis. RESULTS: Mean SNR values were 5.83 +/- 2.2 and 11.68 +/- 2.87 for EPI and non-CPMG SS-FSE DWI, respectively. SNR values measured in DWI using parallel imaging were found to be significantly higher (P < .01). Mean ADCs of the spine were 0.53 +/- 0.15 and 0.35 +/- 0.15 x 10(-3) mm(2)/s for EPI and non-CPMG SS-FSE DWI, respectively. Quality scores were found to be higher for the non-CPMG SS-FSE DWI technique (P < .05). Overall lesion CNR was found to be higher in DWI with non-CPMG SS-FSE. CONCLUSION: The non-CPMG SS-FSE technique provides a significant improvement to current EPI-based DWI of the spine. A study including a larger number of patients is required to determine the use of this DWI sequence as a supplementary tool to conventional MR imaging for increasing diagnostic confidence in spinal pathologic conditions.

Single breath-hold diffusion-weighted MRI of the liver with parallel imaging: initial experience.

AIM: To evaluate prospectively the improvement in the signal:noise ratio (SNR), with the use of parallel technique in single breath-hold diffusion-weighted imaging (DWI) of the liver and its affect on apparent diffusion coefficient (ADC) measurements. MATERIALS AND METHODS: This study was approved by our institutional review board. Written informed consent was obtained from all participants. Fifteen patients underwent single breath-hold DWI of the liver with and without parallel imaging technique. SNR and ADC values were measured over a lesion-free right hepatic lobe by two radiologists in both series. When a focal hepatic lesion was present the contrast:noise ratio (CNR) and ADC were also measured. Paired Student's t-tests were used for statistical analysis. RESULTS: Mean SNR values of the liver were 20.82+/-7.54 and 15.83+/-5.95 for DWI with and without parallel imaging, respectively. SNR values measured in DWI using parallel imaging were found to be significantly higher (p<0.01). Mean ADC of the liver were 1.61+/-0.45 x 10(-3)mm(2)/s and 1.56+/-0.28 x 10(-3)mm(2)/s for DWI with and without parallel imaging, respectively. No significant difference was found between the two sequences for hepatic ADC measurement (p>0.05). Overall lesion CNR was found to be higher in DWI with parallel imaging. CONCLUSION: Parallel imaging is useful in improving SNR of single breath-hold DWI of the liver without compromising ADC measurements.

Blood-flow volume quantification in internal carotid and vertebral arteries: comparison of 3 different ultrasound techniques with phase-contrast MR imaging.

BACKGROUND AND PURPOSE: Optimal estimation of cerebral blood-flow volume (BFV) may be an important indicator for better evaluation of the patients with cerebrovascular disorders. In this study, we compared the BFV values at bilateral internal carotid and vertebral arteries of healthy volunteers obtained with color Doppler, power Doppler, and B-flow ultrasound (US) studies and tried to determine which examination is more correlated with MR phase-contrast quantification. METHODS: BFVs of the internal carotid and vertebral arteries of 40 healthy volunteers (19 men and 21 women; age range, 20-47 years) were measured by using color Doppler, power Doppler, B-flow US and MR phase-contrast imaging. The flow measurements obtained with the sonographic techniques were compared with MR phase contrast, which is accepted as the most reliable method for the estimation of cerebral BFV. RESULTS: Quantification with power Doppler imaging showed the highest values among sonography techniques, followed by color Doppler imaging, B-flow imaging (BFI), and MR phase-contrast flow quantification. There was a statistically significant difference between the flow-volume values obtained with these 4 different techniques (P < .05). BFI yielded the closest values (internal carotid arteries, 238.84 mL/min; vertebral arteries, 51.16 mL/min) to MR phase-contrast flow quantification study with higher correlation rates. CONCLUSION: Flow volumes obtained with BFI showed the highest correlation with MR phase-contrast imaging among 3 different sonography techniques. B-flow sonography may be a very effective and cost-efficient alternative for MR phase-contrast studies for the calculation of cerebral BFV.

Histological and magnetic resonance imaging alterations after irradiation of meniscus using Holmium:YAG laser.

OBJECTIVE: The authors performed an experimental and a prospective clinical study to evaluate the histological and magnetic resonance imaging (MRI) alterations after irradiation of meniscus using holmium:YAG (Ho:YAG) laser VersaPulse Select 60 watts and InfraTome Delivery Systems 30 degrees Handpiece (spot size at fiber tip 0.4 mm; Coherent Medical, Palo Alto, CA). BACKGROUND DATA: Recently, some authors reported a few cases with articular cartilage damage or paraarticular osteonecrosis following arthroscopic knee surgery in which the laser was used to assist in the treatment of meniscal pathology. METHODS: Meniscus specimens in saline immersion were exposed to Ho:YAG laser irradiation. The laser wavelength was 2.1 microm and pulse duration was 250 microsec. Power settings were 1-1.5 joules per pulse and 10-15 Hz. Total laser energy used in these procedures was 2, 3.5, and 6 K joules. Eight patients with meniscal problems underwent arthroscopic partial meniscectomy using Ho:YAG laser. Total laser energy used for these surgeries was 1.5-2.5 K joules. MRI was performed preoperatively and at 6 months postoperatively. RESULTS: At higher energy levels (more than 3 K joules), separation of the gap between the collagen fibers, and a three-dimensional dispersion in the striation were observed on electron microscopic evaluation of meniscus specimens. No patient had abnormal signals in MRI (a sign of articular cartilage damage or osteonecrosis) following arthroscopic laser surgery. CONCLUSION: When higher energy level is required, conventional instruments should be preferred in the treatment of meniscal lesions. Laser should be reserved for the posteriorly located and smaller meniscal lesions.

Cyclosporine-A induced neurotoxicity after renal transplantation.

Cyclosporine-A is a highly potent immunosuppressive agent for solid organ transplantation, but has many side effects including nephrotoxicity, hypertension, gum hyperplasia, hepatotoxicity, and neurotoxicity. Neurotoxicity is a less known toxic effect. The pathogenesis of this effect is unclear. However, it has been postulated that hypomagnesemia, hypocholesterolemia, corticosteroids, and/or neurotoxic substances can induce this syndrome. Also, it has been suggested that the endothelial damage caused by Cyclosporine-A may contribute to neuropeptide-mediated ischemia in the brain and lead to the development of neurological symptoms. In this report, we present a case with reversible neurologic deficits whose symptoms returned to normal after the cessation of cyclosporine-A.

Congenital infiltrating lipomatosis of the face with cerebral abnormalities.

The aim of this study was to describe a possible variant of encephalo-craniocutaneous lipomatosis syndrome. Three cases of congenital infiltrating lipomatosis of the face, associated with cutaneous, subcutaneous, and cerebral abnormalities, are presented. This neurocutaneous syndrome appears very similar to encephalo-craniocutaneous lipomatosis syndrome but lacks the typical eye lesions.

Neonatal cerebral venous thrombosis coexisting with bilateral adrenal hemorrhage.

We report a case of severe perinatal asphyxia with both cerebral venous thrombosis and adrenal hemorrhage who survived with severe sequela including multicystic encephalomalasia, acquired microcephaly and blindness. Hematological investigations showed normal levels of anticardiolipin antibodies, protein C and S levels and activity, antithrombin III levels. Factor V Leiden mutation was negative. The adrenal hemorrhage resolved within three months with glucocorticoid therapy, the cerebral venous thrombosis resolved within two months without treatment. The literature on neonatal cerebral venous thrombosis is also reviewed.

A viable residual spinal hydatid cyst cured with albendazole. Case report.

Spinal hydatid disease is a rare entity that frequently yields to severe, acute-onset neurological deficits. Although the gold standard treatment is total surgical removal of the cysts without inducing any spillage, it may not be possible to perform this in patients with multiple and fragile cysts. In such cases, the neural structures should be adequately decompressed and albendazole should be administered promptly. The authors describe the case of a 13-year-old girl who was admitted with a history of back pain and acute-onset lower-extremity weakness. Magnetic resonance imaging scans demonstrated severe spinal cord compression caused by multiple cysts involving T-4 and the mediastinum. The patient underwent surgery, and the cysts were removed, except for one cyst that was hardly exposed. Following histopathological confirmation of spinal hydatid disease, she was treated with albendazole for 1 year. One year postoperatively, the residual cyst had gradually shrunk and had almost disappeared. Although a single case is not sufficiently promising, we believe that administration of albendazole is efficient to prevent recurrences in cases in which it is not possible to obtain total removal of the cysts without inducing spillage.

Qualitative and quantitative volumetric evaluation of the efficacy of intravenous immunoglobulin in multiple sclerosis: preliminary report.

We conducted a double-blind, placebo-controlled study in 13 patients (aged 22 to 54 years) with relapsing-remitting multiple sclerosis (MS). They were randomly assigned to receive a loading dose of immunoglobulin IgG, 0.4 g/kg body weight/day for 5 consecutive days, followed by single booster doses of 0.4 g/kg/day, or placebo, once a month for 9 months. MRI was obtained before and during the 3rd and 6th months of treatment; examinations in the 9th and 12th months were planned. Qualitative and quantitative blinded assessments were performed. There were seven patients who received active treatment and six who received placebo. Statistical analysis was performed by the Wilcoxon test. A decrease in the size and number of lesions was observed on MRI in five patients (71%) in the treatment group, and in two (33%) of the placebo group at 3-month follow-up. At 6 months follow-up MRI, a decrease in the amount of lesions was observed in all patients treated with i.v. IgG, and in two (33%) of the placebo group; four patients (66%) receiving placebo showed an increase. Quantitative analysis showed a statistically significant decrease in the volume of lesions in treatment group at both 3 and 6 month follow-up. There was no statistically significant change in the placebo group.

Does the Holmium:Yag laser cause osteonecrosis?

Some authors have reported a few cases of paraarticular osteonecrosis following arthroscopic knee surgery in which laser was used to assist in the treatment of cartilage and meniscal pathology. We performed a prospective randomized clinical study to determine if osteonecrosis occurs after arthroscopic laser surgery. Fifty-five patients with cartilage problems in their knee joints were randomized into two groups: the laser group included 30 patients and the conventionally instrumented group consisted of 25 patients. Power settings for the Holmium:YAG laser were 0.5 to 1.5 joules per pulse and 5 and 25 Hertz. Total energy used for the procedures was 1 to 2 K joules. Magnetic resonance imaging was performed on all patients preoperatively and postoperatively (in third, sixth, and thirteenth months). None of the patients had osteonecrosis following arthroscopic laser surgery. When the Holmium:YAG laser is used at an optimal dosage (optimal joule and Hertz) with an optimal technique (keeping the handpiece at an appropriate angle and distance) and for an optimal time (avoiding overtreatment), it does not cause osteonecrosis.