Quantitative Susceptibility Mapping of Time-Dependent Susceptibility Changes in Multiple Sclerosis Lesions.

BACKGROUND AND PURPOSE: MR imaging studies have demonstrated that magnetic susceptibility in multiple sclerosis lesions is dependent on lesion age. The objective of this study was to use quantitative susceptibility mapping to determine whether lesions with a hyperintense rim, indicative of iron-laden inflammatory cells (rim+), follow a unique time-dependent trajectory of susceptibility change compared with those without (rim-). MATERIALS AND METHODS: We studied patients with MS with at least 1 new gadolinium-enhancing lesion and at least 3 longitudinal quantitative susceptibility mapping scans obtained between 1.1 and 6.1 years. Lesions were classified as rim+ if a hyperintense rim appeared on quantitative susceptibility mapping at any time. A multilevel growth curve model compared longitudinal susceptibility among rim+ and rim- lesions. RESULTS: Thirty-two new gadolinium-enhancing lesions from 19 patients with MS were included, and 16 lesions (50%) were identified as rim+. Quantitative susceptibility mapping rim+ lesions were larger than rim- lesions with gadolinium enhancement (P < .001). Among all lesions, susceptibility increased sharply after enhancement to a peak between 1 and 2 years followed by a decrease. The overall susceptibility curve height for rim- lesions was 4.27 parts per billion lower than that for rim+ lesions (P = .01). Rim- lesions demonstrated a higher linear slope relative to rim+ lesions (P = .023) but faster cubic decay relative to rim+ lesions (P = .005). Rim- lesions started decaying approximately 2 years earlier compared with rim+ lesions. CONCLUSIONS: There was a marked difference in the susceptibility temporal trajectory between rim+ and rim- lesions during the first 6 years of lesion formation. Most rim+ lesions retain iron for years after the initial lesion appearance.

Combining Quantitative Susceptibility Mapping with Automatic Zero Reference (QSM0) and Myelin Water Fraction Imaging to Quantify Iron-Related Myelin Damage in Chronic Active MS Lesions.

BACKGROUND AND PURPOSE: A hyperintense rim on susceptibility in chronic MS lesions is consistent with iron deposition, and the purpose of this study was to quantify iron-related myelin damage within these lesions as compared with those without rim. MATERIALS AND METHODS: Forty-six patients had 2 longitudinal quantitative susceptibility mapping with automatic zero reference scans with a mean interval of 28.9 ± 11.4 months. Myelin water fraction mapping by using fast acquisition with spiral trajectory and T2 prep was obtained at the second time point to measure myelin damage. Mixed-effects models were used to assess lesion quantitative susceptibility mapping and myelin water fraction values. RESULTS: Quantitative susceptibility mapping scans were on average 6.8 parts per billion higher in 116 rim-positive lesions compared with 441 rim-negative lesions (P < .001). All rim-positive lesions retained a hyperintense rim over time, with increasing quantitative susceptibility mapping values of both the rim and core regions (P < .001). Quantitative susceptibility mapping scans and myelin water fraction in rim-positive lesions decreased from rim to core, which is consistent with rim iron deposition. Whole lesion myelin water fractions for rim-positive and rim-negative lesions were 0.055 ± 0.07 and 0.066 ± 0.04, respectively. In the mixed-effects model, rim-positive lesions had on average 0.01 lower myelin water fraction compared with rim-negative lesions (P < .001). The volume of the rim at the initial quantitative susceptibility mapping scan was negatively associated with follow-up myelin water fraction (P < .01). CONCLUSIONS: Quantitative susceptibility mapping rim-positive lesions maintained a hyperintense rim, increased in susceptibility, and had more myelin damage compared with rim-negative lesions. Our results are consistent with the identification of chronic active MS lesions and may provide a target for therapeutic interventions to reduce myelin damage.

Dynamic Susceptibility Contrast-Enhanced MR Perfusion Imaging in Assessing Recurrent Glioblastoma Response to Superselective Intra-Arterial Bevacizumab Therapy.

BACKGROUND AND PURPOSE: Recurrent glioblastoma currently has no established standard of care. We evaluated the response of recurrent glioblastoma to superselective intra-arterial cerebral infusion of bevacizumab by using dynamic susceptibility contrast-enhanced MR perfusion imaging. We hypothesized that treatment response would be associated with decreased relative CBV and relative CBF. MATERIALS AND METHODS: Patients were accrued for this study from larger ongoing serial Phase I/II trials. Twenty-five patients (14 men, 11 women; median age, 55 years) were analyzed. Four distinct ROIs were chosen: 1) normal-appearing white matter on the contralateral side, 2) the location of the highest T1 enhancement in the lesion (maximum enhancing), 3) the location of highest relative CBV in the lesion (maximum relative CBV), and 4) nonenhancing T2 hyperintense signal abnormality surrounding the tumor (nonenhancing T2 hyperintensity). RESULTS: There was a statistically significant median percentage change of -32.34% (P = .001) in relative CBV in areas of maximum relative CBV following intra-arterial bevacizumab therapy. There was also a statistically significant median percentage decrease in relative CBF of -30.67 (P = .001) and -27.25 (P = .037) in areas of maximum relative CBV and maximum tumor enhancement, respectively. Last, a trend toward statistical significance for increasing relative CBV in nonenhancing T2 hyperintense areas (median percent change, 30.04; P = .069) was noted. CONCLUSIONS: Dynamic susceptibility contrast-enhanced MR perfusion imaging demonstrated a significant decrease in tumor perfusion metrics within recurrent glioblastomas in response to superselective intra-arterial cerebral infusion of bevacizumab; however, these changes did not correlate with time to progression or overall survival.

Differential diagnosis of normal pressure hydrocephalus by MRI mean diffusivity histogram analysis.

BACKGROUND AND PURPOSE: Accurate diagnosis of normal pressure hydrocephalus is challenging because the clinical symptoms and radiographic appearance of NPH often overlap those of other conditions, including age-related neurodegenerative disorders such as Alzheimer and Parkinson diseases. We hypothesized that radiologic differences between NPH and AD/PD can be characterized by a robust and objective MR imaging DTI technique that does not require intersubject image registration or operator-defined regions of interest, thus avoiding many pitfalls common in DTI methods. MATERIALS AND METHODS: We collected 3T DTI data from 15 patients with probable NPH and 25 controls with AD, PD, or dementia with Lewy bodies. We developed a parametric model for the shape of intracranial mean diffusivity histograms that separates brain and ventricular components from a third component composed mostly of partial volume voxels. To accurately fit the shape of the third component, we constructed a parametric function named the generalized Voss-Dyke function. We then examined the use of the fitting parameters for the differential diagnosis of NPH from AD, PD, and DLB. RESULTS: Using parameters for the MD histogram shape, we distinguished clinically probable NPH from the 3 other disorders with 86% sensitivity and 96% specificity. The technique yielded 86% sensitivity and 88% specificity when differentiating NPH from AD only. CONCLUSIONS: An adequate parametric model for the shape of intracranial MD histograms can distinguish NPH from AD, PD, or DLB with high sensitivity and specificity.

Metabolic response of glioblastoma to superselective intra-arterial cerebral infusion of bevacizumab: a proton MR spectroscopic imaging study.

BACKGROUND AND PURPOSE: SIACI of bevacizumab has emerged as a promising novel therapy in the treatment of recurrent GB. This study assessed the potential of (1)H-MRS as an adjunctive technique in detecting metabolic changes reflective of antiproliferative effects of targeted infusion of bevacizumab in the treatment of GB. MATERIALS AND METHODS: Eighteen patients enrolled in a phase I/II study of SIACI of bevacizumab for treatment of recurrent GB were included. Concurrent MR imaging and (1)H-MRS scans were performed before and after treatment. Five distinct morphologic ROIs were evaluated for structural and metabolic changes on MR imaging and (1)H-MRS, which included enhancing, nonenhancing T2 hyperintense signal abnormality, and multiple control regions. Pre- and post-SIACI of bevacizumab peak areas for NAA, tCho, tCr, as well as tCho/tCr and tCho/NAA ratios, were derived for all 5 ROIs and compared using the Wilcoxon signed-rank test. RESULTS: A significant median decrease of 25.99% (range -55.76 to 123.94; P = .006) in tCho/NAA was found post-SIACI of bevacizumab relative to pretreatment values in regions of enhancing disease. A trend-level significant median decrease of 6.45% (range -23.71 to 37.67; P = .06) was noted in tCho/NAA posttreatment in regions of nonenhancing T2-hyperintense signal abnormality. CONCLUSIONS: The results of this (1)H-MRS analysis suggest that GB treatment with SIACI of bevacizumab may be associated with a direct antiproliferative effect, as demonstrated by significant reductions of tCho/NAA after the intervention.

Imaging features of a cecal lipoma as a lead point for colo-colonic intussusception.

Intussusception is a rare occurrence in the adult population with most of the cases seen during the childhood period. Compared with the pediatric intussusceptions, there is more often an underlying cause in adults. Lipoma as a lead point for colonic intussusception is rare. Ultrasound may be helpful in the diagnosis, but computed tomography is more reliably used for differential diagnosis. An adult patient with colo-colonic intussusception diganosed with ultrasound and confirmed with computed tomography is presented.

Primary epiploic appendagitis: the role of computed tomography in diagnosis.

Primary epiploic appendagitis is a rare entity that occurs due to torsion and inflammation of the epiploic appendages. Clinically, this entity may be mistaken for acute abdomen with resultant unnecessary surgery. In contrast to acute surgical abdomen, epiploic appendagitis usually does not require surgical treatment; most of the patients resolve with conservative management. Diagnosis can be achieved with imaging modalities of which computed tomography is the gold standard procedure. Herein, a patient who presented with acute abdomen like clinical picture, with the computed tomography demonstration of primary epiploic appendagitis, is presented.

Cystic splenosis mimicking a renal mass: a case report and review of the literature.

Splenosis is a well-known entity, caused by autotransplantation of splenic tissue as a result of trauma or splenectomy. Patients are generally asymptomatic, and this entity is diagnosed during routine diagnostic imaging. Cystic changes in splenic implants have been defined before but, as to our knowledge, radiological demonstration of cystic components has not been published in the literature. It is well-known that unusual locations of the splenic implants create diagnostic problems, sometimes leading to unnecessary surgical interventions. In this report splenosis, mimicking a renal tumour, with cystic changes in the biggest splenule, and diagnosis with ferrumoxide-enhanced MRI is presented.

Phe 84 deletion of the PMP22 gene associated with hereditary motor and sensory neuropathy HMSN III with multiple cranial neuropathy: clinical, neurophysiological and magnetic resonance imaging findings.

Hereditary motor and sensory neuropathy (HMSN) is a heterogeneous group of peripheral neuropathies which are diagnosed on the basis of clinical, electrophysiological and neuropathological findings. Among the hypertrophic demyelinating neuropathies, HMSN III is the most severe. It is often associated with de novo mutations in the genes encoding for peripheral myelin proteins. While peripheral nerve hypertrophy is an expected finding in HMSN III, cranial nerve hypertrophy is exceptional. Here we describe a mutation in the PMP22 gene in a 19-year-old man with infantile onset of sensory motor polyneuropathy without family history and multiple cranial nerve hypertrophy shown by cranial magnetic resonance imaging.

Indirect MR arthrography of the shoulder in detection of rotator cuff ruptures.

The aim of this study was to compare the efficacy of indirect MR arthrography images obtained following intravenous contrast injection and conventional MR imaging in the diagnosis of rotator cuff tears. Twenty-four patients with clinically suspected rotator cuff disease were examined. Conventional MR images and post-contrast indirect MR arthrography images were obtained. All images were evaluated in a blinded fashion by two musculoskeletal radiologist. Results were than analyzed depending on surgical output. The correlation coefficient (Spearman rank correlation test) and the kappa values for agreement between surgery and imaging techniques were calculated. The correlation coefficients between indirect MR arthrography and surgery for reader 1 and reader 2 were 0.9137 and 0.9773, respectively. Whereas the agreement between conventional MR imaging and surgery was moderate (n = 0.383-0.571), the agreement between indirect MR arthrography and surgery was excellent (n = 0.873-0.936). We suggest the use of indirect MR arthrography technique when conventional MR images are equivocal in diagnosis of rotator cuff disease.

Brucellar spondylitis: MRI findings.

This study was carried out to identify the distinguishing features of brucellosis on magnetic resonance imaging (MRI). MRI examinations were performed in 14 patients with spinal brucellosis. A 1-T Magnetom (Erlangen, Siemens) was used to obtain T1-weighted (TR/TE 500/30) and T2-weighted (TR/TE 2000/80/20) spin echo sequences, in both sagittal and axial planes. Thirty-three percent of the vertebrae and 18 levels of disc were involved in the 14 brucellar spondylitis cases. Eleven patients (79.8%) with discitis revealed anterior superior vertebral body involvement. Fourteen (77.7%) of the levels with discitis displayed soft tissue swelling without presence of abscess formation. Seven facet joints of five patients with discitis displayed signal increase after contrast enhancement. Vertebral body signal changes without morphologic changes marked signal increase in the intervertebral disc on T2-weighted and contrast-enhanced sequences, and soft tissue involvement without abscess formation can be accepted as specific MRI features of brucellar spondylitis. The facet joint signal changes following contrast enhancement is another MRI sign of spinal brucellosis, which has not been mentioned so far.

Evaluation of bone height and bone density by computed tomography and panoramic radiography for implant recipient sites.

The objective was to compare the bone height and bone density measurements of implant recipient sites by panoramic radiography and computed tomography. Thirty-seven sites of 21 patients were evaluated using both panoramic radiography and computed tomography. The bone height was measured as the vertical distance from the alveolar crest to the closest anatomical landmark. Density was compared by means of densitometric measurements. Data was evaluated using paired t-test and Pearson's correlation coefficient analysis. Although bone heights measured with the two imaging modalities differed significantly (p < 0.05), there was a significant correlation between bone density measurements (r = 0.93, p = 0.0). Measurements of bone height as well as bone density was found to be comparable using either radiographic method.

Herpes encephalitis in children. MRI assessment.

The magnetic resonance imaging (MRI) findings in 14 patients with biopsy or polymerase chain reaction proven herpes simplex encephalitis were retrospectively reviewed to evaluate the diagnostic value of MRI in the early diagnosis of herpes simplex encephalitis in children. In addition to the early findings, follow-up MRI scans were obtained in four patients. Typical limbic system involvement was seen in 78 percent of the cases. Contrast-enhanced MRI was found to be superior to routine MRI sequences and computerized tomography (CT) in the early detection of inflammation. Follow-up MR images in four patients demonstrated the volume loss and late petechial hemorrhage in the involved regions. Magnetic resonance imaging is the method of choice in the diagnosis and follow-up of herpes simplex encephalitis.

Aneurysmal bone cyst secondary to infantile cartilaginous hamartoma of rib.

We report the first case, in a 4-month-old girl, of an aneurysmal bone cyst secondary to infantile cartilaginous hamartoma of the rib. Infantile cartilaginous hamartoma of the rib (benign mesenchymoma) is a large, expansile tumour that is characterised by cartilaginous, vascular and primitive-appearing stromal and mesenchymal elements. Most cases are diagnosed at less than 1 year of age and may even be congenital. Aneurysmal bone cyst may be a secondary lesion to pre-existing tumours such as giant cell tumours, osteoblastomas, angiomas and chondroblastomas. This unique case is presented with radiological and pathological findings.

Bone bruises detected by magnetic resonance imaging following lateral ankle sprains.

Although bone bruises have been well described in the knee joint, little is known about their presence in the ankle joint. The present study attempted to document the association of bone bruises with lateral ankle sprains. Magnetic resonance (MR) images were obtained from 60 consecutive patients with lateral ankle sprains between April 1994 and June 1995. There were 29 men and 31 women, aged on average 25 years (range 12-68 years). All of the patients presented within 3 weeks of the sprain. MRI examinations were done within 3 weeks of the injury in 15, after 3-6 weeks in 21, and after 6-8 weeks in 24 cases. There were 28 first-time sprains, while 32 patients had suffered one or more sprains before the most recent one. Plain radiographs showed no evidence of osseous abnormality. Following the conventional MRI examination, magnetic resonance arthrography (MRA) was done by injecting 2 mM of gadolinium diethylene triamine penta-acetic acid (DTPA) into the joint under fluoroscopic control, and the same images were obtained again to search for ligamentous lesions. A total of 11 bone bruises were detected in 10 ankles. In this group of patients, there were 5 men and 5 women aged on average 27 years (range 12-50 years). Four MRI examinations were done within 3 weeks, while six were done 3-6 weeks after the injury. One ankle which had suffered one previous sprain and complete ruptures of anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) had two lesions (talus and navicula). In another recurrent case with complete ATFL and CFL ruptures, the lesion was found in the calcaneus. The remaining eight lesions were in the talus in eight ankles. The ligamentous lesions in these ankles included three complete ATFL and CFL ruptures, and four isolated ATFL ruptures; in one ankle there were no ligamentous lesions. The location of talar bruises was medial in six and lateral in three ankles. The incidence of bone bruises associated with isolated ATFL lesions was 16% (4/25). With combined ATFL and CFL lesions the incidence was 50% (5/10). The incidence of ankles with bone bruises and first-time and recurrent sprains was 7% (2/28) and 25% (8/32), respectively. The occurrence of bone bruises should be kept in mind following ankle sprains. Their clinical significance in the long term remains to be determined.

Diagnostic value of MR arthrography in detection of intrinsic carpal ligament lesions: use of cine-MR arthrography as a new approach.

Twenty-five patients with chronic wrist pain and a preliminary diagnosis of carpal instability were examined with conventional MR imaging and MR arthrography with single compartment intra-articular injection. A new cine-MR arthrography technique, with image acquisition at every 5 s during intra-articular injection, was performed in 17 subjects. The purpose of this study was to determine the diagnostic value of MR arthrography in ligamentous lesions of the wrist and to assess the value of cine-MR arthrography in comparison with arthroscopy and/or surgery. Magnetic resonance arthrography, a semi-invasive technique, increased the diagnostic accuracy of intrinsic carpal ligament injuries. Cine-MR arthrography can be considered as a promising technique especially for the evaluation of lunatotriquetral and scapholunate ligament injuries of the wrist.

Magnetic resonance imaging in the evaluation of eyes treated with silicone oil.

BACKGROUND AND OBJECTIVE: To evaluate the sensitivity of magnetic resonance imaging (MRI) in detecting retinal detachment (RD) in eyes filled with silicone oil, and to determine the MRI characteristics of silicone oil in vivo. PATIENTS AND METHODS: Seven eyes of seven patients with RD and eight eyes of eight patients without RD after silicone oil surgery were included in the study. All of the patients had clear media. MRI was performed in these patients. The results of ophthalmic examinations were compared with MRI findings. RESULTS: MRI detected six of the seven detached retinas. The multiplanar imaging capability of MRI helped in showing the RDs in various locations. The chemical shift artifact exaggerated the retinal thickness and made the detached retina visible. Fat suppressed images showed the silicone oil-corneal contact clearly. CONCLUSION: MRI is an effective technique for demonstrating RD in eyes filled with silicone oil and can be used successfully in eyes with opaque media.

99mTc-MIBI scintigraphy in metastatic renal cell carcinoma: clinical validation of the relationship between 99mTc-MIBI uptake and P-glycoprotein expression in tumour tissue.

Technetium-99m hexakis-2-methoxyisobutylisonitrile (MIBI) and thallium-201 imaging was performed in a patient with metastatic renal cell carcinoma (RCC), which is a well-known tumour type demonstrating P1-glycoprotein (PGP) overexpression. Two scintigraphic patterns - Tl(+)/MIBI(-) in primary tumour and Tl(+)/MIBI(+) in metastatic tumour - were observed, suggesting high- and low-level PGP expression, respectively. Immunochemical study for PGP revealed strong staining of the primary tumour cells. This case clinically validates the previously suggested relationship between 99mTc-MIBI uptake and PGP expression.

An atypical psoriatic spondylitis case, successfully treated with methotrexate.

We present a 45-year-old male patient who was hospitalized with lumbar disc herniation and whose control magnetic resonance imaging (MRI) findings initially suggested brucella spondylitis. Definitive diagnosis, however, indicated psoriatic spondylitis and the patient was successfully treated with methotrexate. A diagnosis of lumbar disc herniation was made in May 1991, during his psoriasis vulgaris treatment. He was hospitalized in August 1994 with a complaint of low-back pain persisting over the last six months despite treatment with analgesics. He was evaluated by clinical, radiological, laboratory and scintigraphic methods, following control MRI findings suggesting infection of vertebral bodies, particularly pointing to brucellosis in addition to disc herniation. A diagnosis of psoriatic spondylitis was finally established and 7.5 mg methotrexate weekly was administered. Significant improvement was obtained of psoriatic skin lesions, low-back pain and MRI findings through a six-month treatment period.