Emergency embolization of actively bleeding renal angiomyolipoma in a patient of tuberous sclerosis.

Renal angiomyolipoma is a benign hamartomatous lesion which contains varying proportions of abnormal blood vessels along with muscle and fat component. Tuberous sclerosis predisposes to angiomyolipoma, and when associated, the lesion is often large with increased risk of hemorrhage and complications. When this occurs, transarterial embolization and surgery are the treatment options. Such a patient presented to us with acute onset of symptoms, and on account of severe anemia with active bleeding, transarterial embolization was performed. This was followed by elective nephrectomy without any complications. We present the imaging aspects of tuberous sclerosis and emphasize role of interventional radiology in this case.

Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Diffusion tensor metrics such as maximum FA and minimum CS can help to differentiate HGA from LGA.

Combined transarterial and percutaneous coiling of a spontaneous vertebrovertebral fistula associated with neurofibromatosis Type 1. Case report.

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.

Diffusion tensor mode in imaging of intracranial epidermoid cysts: one step ahead of fractional anisotropy.

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: Thus, advanced imaging modalities like DTI with DTM can provide information regarding the microstructural anatomy of the epidermoid cysts.

Imaging findings in intracranial aspergillus infection in immunocompetent patients.

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.