Browsing by Author "Saini, Jitender"

Now showing 1 - 10 of 10
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    Aberrant petrous internal carotid artery with cochlear anomaly-an unusual association
    (SURGICAL AND RADIOLOGIC ANATOMY, 2008)
    The magnetic resonance imaging (MRI) in a female patient who presented with headache and hearing loss revealed aberrant course of the petrous segment of internal carotid artery (ICA). Computed tomography (CT) of the temporal bone done to confirm the findings of MRI revealed aberrant course of right ICA, a persistent stapedial artery (PSA) and absent foramen spinosum on the same side. In addition patient had a cystic cochleovestibular anomaly on the right side with both conditions may probably be contributing to her hearing loss.
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    Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases
    (NEURORADIOLOGY, 2011)
    Diffusion weighted imaging and diffusion tensor imaging (DTI) give information about the amount and directionality of water diffusion occurring in a given tissue. Here we study the role of diffusion tensor metrics including fractional anisotropy (FA) and spherical anisotropy (CS) in preoperative grading of diffusely infiltrating astrocytomas.We performed DTI in 38 patients with pathologically proven diffusely infiltrating astrocytomas, who were classified into two groups, i.e., 15 patients with high-grade astrocytoma (HGAs, WHO grade III and IV) and 23 patients with low-grade astrocytoma (LGAs, WHO grade II). We measured maximum FA and minimum CS values in all cases from tumor. Histopathological diagnosis was established in all cases.The mean maximum FA values were higher in HGA (0.583 +/- 0.104) than LGA (0.295 +/- 0.058), while mean minimum CS values were lower in HGA (0.42 +/- 0.121) than LGA (0.722 +/- 0.061). The difference in the diffusion tensor indices between HGA and LGA was found to be statistically significant with P value of < 0.001. Keeping cutoff FA value of 0.4, all HGAs showed higher maximum FA values, and all LGAs showed lower maximum FA values. Also, all HGAs showed minimum CS values less than a cutoff value of 0.6, and all LGAs showed minimum CS values higher than 0.6.Diffusion tensor metrics such as maximum FA and minimum CS can help to differentiate HGA from LGA.
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    Combined transarterial and percutaneous coiling of a spontaneous vertebrovertebral fistula associated with neurofibromatosis Type 1 Case report
    (JOURNAL OF NEUROSURGERY, 2009)
    The authors report a rare case of spontaneous left vertebrovertebral fistula associated with neurofibromatosis Type 1 in a young woman. The patient had undergone previous failed surgical attempts to close the fistula and presented to the authors with recurrence of the fistula and neurological deterioration. Successful obliteration of the fistula with combined transarterial and percutaneous coiling with Guglielmi detachable coils resulted in disappearance of the fistula and significant neurological improvement. (DOI: 10.3171/2008.12.JNS081209)
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    Diffusion Tensor and Tensor Metrics Imaging in Intracranial Epidermoid Cysts
    (JOURNAL OF MAGNETIC RESONANCE IMAGING, 2009)
    Purpose: To explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) In characterizing the structural pathology of epidermoid cysts. DTI gives Information about the tissue structure: a high fractional anisotropy (FA) indicates a highly structured orientation of the tissue, fibers, or white matter tracts. Based on the tensor rank, a set of three metrics has been described that can be used to measure the directional dependence of diffusion: linear anisotropy (CL), planar anisotropy (CP), and spherical anisotropy (CS). DTM takes into account the shape of diffusion anisotropy and hence may provide better insight Into the orientation of structures than FA.Materials and Methods: DTI was performed in three patients with epidermoid cysts. FA, directionally-averaged mean diffusivity (Dav), exponential apparent diffusion coefficient (eADC), and DTM, such as CL, CP, and CS, were measured from the tumor core as well as from the normal-appearing white matter. Histopathological correlation was obtained.Results: Epidermoid cysts showed high FA with Dav values similar to that of normal white matter. eADC maps did not show any restriction of diffusion. FA values were. high, but not. as high as that for the white matter, CP values were higher and CL values were lower than those obtained for the white matter in various regions.Conclusion: High CP values suggest preferential diffusion of water molecules along a two-dimensional geometry, which could be attributed to the well-structured orientation of keratin filaments and flakes within the tumor as demonstrated by histopathology. Advanced imaging modalities like DTI with DTM can provide Information regarding the microstructural anatomy of the epidermoid cysts.
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    Diffusion tensor mode in imaging of intracranial epidermoid cysts: one step ahead of fractional anisotropy
    (NEURORADIOLOGY, 2009)
    The signal characteristics of an epidermoid on T2-weighted imaging have been attributed to the presence of increased water content within the tumor. In this study, we explore the utility of diffusion tensor imaging (DTI) and diffusion tensor metrics (DTM) in knowing the microstructural anatomy of epidermoid cysts.DTI was performed in ten patients with epidermoid cysts. Directionally averaged mean diffusivity (D (av)), exponential diffusion, and DTM-like fractional anisotropy (FA), diffusion tensor mode (mode), linear (CL), planar (CP), and spherical (CS) anisotropy were measured from the tumor as well as from the normal-looking white matter.Epidermoid cysts showed high FA. However, D (av) and exponential diffusion values did not show any restriction of diffusion. Diffusion tensor mode values were near -1, and CP values were high within the tumor. This suggested preferential diffusion of water molecules along a two-dimensional geometry (plane) in epidermoid cysts, which could be attributed to the parallel-layered arrangement of keratin filaments and flakes within these tumors.Thus, advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts.
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    Imaging Findings in Intracranial Aspergillus Infection in Immunocompetent Patients
    (WORLD NEUROSURGERY, 2010)
    AIM: To study the neuroimaging features of craniocerebral aspergillosis infection in immunocompetent patients.MATERIALS AND METHODS: The clinical and imaging data of 12 patients of aspergillus fungal infection were retrospectively reviewed. Diagnosis of fungal infection was confirmed by histopathologic examination of surgically excised specimen, stereotactic biopsy material, or endoscopic sinus biopsy. The radiologic studies were evaluated for anatomic distribution of lesions, signal intensity, contrast enhancement, presence of hemorrhage, diffusion restriction, perfusion, and spectroscopy characteristics. Medical records, biopsy reports, and autopsy findings were also reviewed.RESULTS: Twelve cases of aspergillosis infections in immunocompetent patients were diagnosed at our hospital over a period of 10 years. Lesions could be classified based on imaging of lesions of sinonasal origin, intracranial mass lesion including both parenchymal or extraparenchymal meningeal based and stroke. Coexisting meningitis was also noted in one patient. Disease of sinonasal origin commonly showed invasion of the cavernous sinus and orbital apex resulting in visual symptoms and multiple cranial nerve palsies. Intracranial mass lesions without sinonasal involvement were seen in five cases that included isolated parenchymal lesion in two patients and dural-based mass lesions in three patients. Isolated intraparenchymal lesions included two cases of fungal cerebritis. Dural-based lesions were large granulomas with a significant mass effect. Infarcts were seen in three patients and angiography showed vessel narrowing or occlusion in all the three patients. CT demonstrated isodense to hyperdense attenuation of primary sinus disease with evidence of bone destruction in all the cases of sinonasal origin. Primary parenchymal lesions showed heterogenous attenuation with predominantly low-density areas. Dural-based lesions showed isodense to hyperdense attenuation. Magnetic resonance imaging revealed isointense to hypointense signal intensity on both T(1)-weighted (T1W) and T(2)-weighted (T2W) images in all lesions of sinonasal origin and isolated dural-based mass lesions. Primary parenchymal lesions showed heterogenous signal intensity pattern with predominantly hypointense signal on T1W and hyperintense signal on T2W images. Diffusion weighted imaging, magnetic resonance spectroscopy, and perfusion-weighted imaging gave valuable ancillary information in these cases.CONCLUSION: Sinonasal disease with intracranial extension is the commonest pattern of aspergillus infection followed by intracranial mass lesions. Hyperdense sinonasal disease with bone destruction and intracranial extension on computed tomography, hypointense signal intensity of the lesions on T2W magnetic resonance images, presence of areas of restricted diffusion, decreased perfusion on perfusion-weighted imaging, and presence of hemorrhages are key to the imaging diagnosis of fungal infection.
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    Role of three-dimensional fluid-attenuated inversion recovery (3D FLAIR) and proton density magnetic resonance imaging for the detection and evaluation of lesion extent of focal cortical dysplasia in patients with refractory epilepsy
    (ACTA RADIOLOGICA, 2010)
    Background: Focal cortical dysplasia (FCD) is often associated with epilepsy. Identification of FCD can be difficult due to subtle magnetic resonance imaging (MRI) changes. Though fluid-attenuated inversion recovery (FLAIR) sequence detects the majority of these lesions, smaller lesions may go unnoticed while larger lesions may be poorly delineated.Purpose: To determine the ability of a specialized epilepsy protocol in visualizing and delineating the extent of FCD.Material and Methods: We compared the imaging findings in nine patients with cortical malformation who underwent routine epilepsy MR imaging as well as a specialized epilepsy protocol. All imaging was done on a 1.5T MR unit. The specialized epilepsy protocol included 3D FLAIR in the sagittal plane as well as proton density (PD) and high-resolution T2-weighted (T2W) images in the transverse plane.Results: In all nine patients, the specialized protocol identified lesion anatomy better. In three patients in whom routine MRI was normal, the specialized epilepsy protocol including 3D FLAIR helped in identifying the lesions. One of these patients underwent surgery, and histo-pathology revealed a cortical dysplasia. In one patient, lesion characterization was improved, while in the remaining patients the extent of the FCD was more clearly demonstrated in the 3D FLAIR and PD images. Statistical analysis of images for cortical thickness, cortical signal intensity, adjacent white matter abnormalities, and gray-white matter junction showed significant statistical difference in the ability of 3D FLAIR to assess these aspects over conventional images. PD images were also found superior to the routine epilepsy protocol in assessment of cortical signal, adjacent white matter, and gray-white matter junction.Conclusion: Specialized MRI sequences and techniques should be performed whenever there is a high suspicion of cortical dysplasia, especially when they remain occult on conventional MR protocols. These techniques can also be used to define lesion extent more precisely.
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    Susceptibility weighted imaging in the diagnostic evaluation of patients with intractable epilepsy
    (EPILEPSIA, 2009)
    Aim: Dedicated magnetic resonance imaging (MRI) protocol can diagnose epileptogenic abnormalities in patients with intractable epilepsy. However, it is not sufficiently sensitive to detect small calcified lesions that may result from infections, tumors, or vascular malformations. This study aims to study the impact of the addition of T2*gradient echo/susceptibility weighted imaging (T2*GRE/SWI) sequence to a dedicated MRI protocol.Method: One hundred thirty-seven patients with intractable epilepsy underwent MRI using conventional epilepsy protocol with addition of T2*GRE/SWI sequence. Comparison of the images with and without these sequences was done for detection of calcified abnormalities/vascular abnormalities. In patients with calcified lesions, MRI findings were correlated either with histopathology or computerized tomography (CT) to confirm the presence of calcification.Results: In 16 patients the sequence gave additional information compared to conventional imaging protocol. The sequence helped in better characterization of lesions in all patients. In three patients it helped in detecting the lesion and in another three it appeared useful as it best characterized the lesions. Additional lesions were detected in two patients with old calcified granulomas. Important additional information was supplied in four patients, whereas in the remaining patients lesion conspicuity was increased.Conclusion: T2*GRE/SWI sequence should form part of routine epilepsy protocol as it increases sensitivity by detecting occult calcified lesions or vascular malformations that may be responsible for the patient's seizures. This is especially important in patients from developing countries who have post-infective calcified lesions responsible for seizures and who undergo only MRI as the imaging modality for intractable seizures.
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    T1 Hyperintense Cystic Lesion - an Epidermoid or an Abscess?
    (CLINICAL NEURORADIOLOGY, 2010)
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    Utility of susceptibility-weighted MRI in differentiating Parkinson's disease and atypical parkinsonism
    (NEURORADIOLOGY, 2010)
    Neuropathological studies report varying patterns of brain mineralization in Parkinson's diseases (PD), progressive supranuclear palsy (PSP), and Parkinson variant of multiple system atrophy (MSA-P). Susceptibility-weighted imaging (SWI) is the ideal magnetic resonance imaging (MRI) technique to detect mineralization of the brain. The purpose of this study was to test if SWI can differentiate PD, PSP, and MSA-P.Eleven patients with PD, 12 with PSP, 12 with MSA-P, and 11 healthy controls underwent SWI of the brain. Hypointensity of putamen, red nucleus, substantia nigra, and dentate nucleus in all groups were measured using an objective grading scale and scored from 0 to 3.In PSP, hypointensity score of red nucleus was higher than that in MSA-P (p = 0.001) and PD (p = 0.001), and a score of a parts per thousand yen2 differentiated the PSP group from the PD and MSA-P groups. Putaminal hypointensity score was higher in PSP when compared to that in PD (p = 0.003), and a score of a parts per thousand yen2 differentiated PSP from PD groups. SWI hypointensity scores of red nucleus and putamen had an excellent intrarater and interrater correlation. Substantia nigra hypointensity score of the PSP group was higher than that of the MSA-P (p = 0.004) and PD (p = 0.006) groups, but the scores had only a moderate intrarater and interrater correlation.SWI shows different patterns of brain mineralization in clinically diagnosed groups of PD, PSP, and MSA-P and may be considered as an additional MR protocol to help differentiate these conditions.