96 research outputs found
Radiologic-pathologic autopsy correlation of an internal watershed infarct, a case report
Internal watershed infarcts (IWIs) occur at the junction of the deep and superficial perforating arterial branches of the cerebrum. Despite documentation in the radiology literature, IWIs are rarely encountered at the time of autopsy. Here, we report the case of a 59-year-old incarcerated male who was brought to the emergency department after being found unresponsive on the floor of his jail cell. Initial examination and imaging demonstrated right-sided hemiplegia, aphasia, right facial droop, and severe stenosis of the left middle cerebral artery, respectively. Repeat imaging 4 days after admission and 26 days before death demonstrated advanced stenosis of the intracranial, communicating segment of the right internal carotid artery, a large acute infarct in the right posterior cerebral artery territory, and bilateral deep white matter ischemic changes with a right-sided “rosary-like” pattern of injury that is typical of IWIs. Postmortem gross examination showed that the right deep white matter lesion had progressed to a confluent, “cigar-shaped” subacute IWI involving the right corona radiata. This is the first well-documented case of an IWI with radiologic imaging and photographic gross pathology correlation. This case uniquely highlights a rarely encountered lesion at the time of autopsy and provides an excellent visual representation of internal watershed neuroanatomy
MULTILEVEL FUNCTIONAL PRINCIPAL COMPONENT ANALYSIS FOR HIGH-DIMENSIONAL DATA
We propose fast and scalable statistical methods for the analysis of hundreds or thousands of high dimensional vectors observed at multiple visits. The proposed inferential methods avoid the difficult task of loading the entire data set at once in the computer memory and use sequential access to data. This allows deployment of our methodology on low-resource computers where computations can be done in minutes on extremely large data sets. Our methods are motivated by and applied to a study where hundreds of subjects were scanned using Magnetic Resonance Imaging (MRI) at two visits roughly five years apart. The original data possesses over ten billion easurements. The approach can be applied to any type of study where data can be unfolded into a long vector including densely bserved functions and images
Paradoxically Decreased Signal Intensity on Postcontrast Short-TR MR Images
Seven lesions are presented in which short TRfshort TE images obtained immediately after IV administration of gadopentetate dimeglumine demonstrated an apparent decrease in signal intensity compared with precontrast short TRfshort TE images. All seven lesions were hyperintense on precontrast short TRfshort TE images. In four cases in which long TRflong TE scans were also obtained, the lesions were hypointense. This phenomenon may be due to a dominant T2 shortening effect by the contrast material that "overwhelms" T1 shortening even on short TRfshort TE scans. Other compounding factors may include variations in scanning variables, receive and transmit attenuations, or a photographic phenomenon due to window widths and center levels. The use of gadopentetate dimeglumine for evaluating CNS disease has become commonplace. With a standard dose of 0.1 mmolfkg , lesions that show contrast enhancement usually become bright on short TRfTE images. The explanation for this phenomenon is the shortening of T1 relaxation by the paramagnetic contrast agent on adjacent protons. As with any dipolar interaction , T2* shortening also occurs; however, its effect is usually inapparent on the short TR/short TE (T1-weighted) scans. We present seven cases in which there was a decrease in signal intensity after IV administration of contrast material in lesions that were hyperintense on precontrast short TR/short TE scans. Materials and Methods In the past 2 years we have observed seven cases in which there appeared to be a decrease in lesion signal intensity on postcontrast short TR (600-850)/short TE (20/30) images compared with precontrast scans. All scans were obtained on high-field 1.5-T scanners. Standard doses of gadopentetate dimeglumine (Magnevist, Berlex Industries , Wayne, NJ) at 0.1 mmolfkg were administered intravenously followed by immediate (i .e. ,< 5 min) postcontrast short TR scans. In three case
FUNCTIONAL PRINCIPAL COMPONENTS MODEL FOR HIGH-DIMENSIONAL BRAIN IMAGING
We establish a fundamental equivalence between singular value decomposition (SVD) and functional principal components analysis (FPCA) models. The constructive relationship allows to deploy the numerical efficiency of SVD to fully estimate the components of FPCA, even for extremely high-dimensional functional objects, such as brain images. As an example, a functional mixed effect model is fitted to high-resolution morphometric (RAVENS) images. The main directions of morphometric variation in brain volumes are identified and discussed
Allergic fungal sinusitis: CT findings.
PURPOSE : To determine the computed tomographic (CT) findings in patients with allergic fungal sinusitis. MATERIALS AND METHODS: The authors retrospectively reviewed CT scans and surgical and histopathologic reports in 45 patients (27 male, 18 female; age range, 8-68 years) with allergic fungal sinusitis from multiple institutions. The median age (25 years) and demographics of the patients were determined. Two head and neck radiologists together evaluated the CT scans for the presence of intrasinus high-attenuation areas, extent of sinus involvement, bone expansion and thinning, bone erosion, and extension of disease into the adjacent soft tissues. RESULTS: Allergic fungal sinusitis was more common in male patients and in patients aged 20-30 years. All patients had increased intrasinus attenuation at non-contrast material-enhanced CT. Multiple sinus involvement occurred in 43 patients. Bilateral involvement was more common than unilateral disease. Forty-four patients had complete opacification of at least one of the involved sinuses; 43 of these patients had expansion of an involved sinus, 42 had remodeling and thinning of the bony sinus walls, and 41 had erosion of the sinus wall. CONCLUSION: Allergic fungal sinusitis is a distinct clinical entity with nonspecific symptoms that may be initially suggested by the CT findings. These findings should alert the clinician to the possibility of allergic fungal sinusitis and prompt other diagnostic studies to establish the diagnosis and treatment plan
Surgical management of pulmonary inflammatory pseudotumors: A single center experience
<p>Abstract</p> <p>Background</p> <p>The pulmonary inflammatory pseudotumor (PIP) is a rare disease. It is still debated whether it represents an inflammatory lesion characterized by uncontrolled cell growth or a true neoplasm. PIP is characterized by a cellular polymorphism.</p> <p>Methods</p> <p>We retrospectively analyzed 8 patients with PIP treated by surgery between 2001 and 2009. Preoperative thoracic computed tomography (CT) scan was performed in all cases. All patients underwent preoperative bronchoscopy with washing and brushing and/or transbronchial biopsy and preoperative cytology examination</p> <p>Results</p> <p>There were 5 men and 3 women, aged between 38 and 69 years (mean of 58 years). 3 patients (37%) were asymptomatic. The others had symptoms characterized by chest pain, shortness of breath and persistent cough or hemoptysis. 5 patients had neutrophilic leucocytosis. CT scan demonstrated solitary nodules (maximum diameter <3 cm) in 5 patients (62%) and lung masses (maximum diameter >3 cm) in 3 patients (37%). In 2 patients there were signs of pleural infiltration. Distant lesions were excluded in all cases. A preoperative histology examination failed to reach a definitive diagnosis in all patients. At surgery, we performed two lobectomies, one segmentectomy and five wedge resections, these being performed with videothoracoscopy (VATS), except for one patient where open surgery was used. Complete tumor resection was obtained in all patients. According to the Matsubara classification, there were 2 cases of organizing pneumonia, 5 cases of fibrous histiocytoma and one case of lymphoplasmacytoma. All patients were discharged alive from hospital between 4 and 7 days after surgery. At follow-up CT scan performed annually (range 11 to 112 months) (mean 58 months), there were no residual lesions, neither local nor distant recurrences.</p> <p>Conclusions</p> <p>PIP is a rare disease. Many synonyms have been used for this disease, usually in relation to the most represented cell type. The true incidence is unclear. Preoperative diagnosis is difficult to reach, despite performing a bronchoscopy or a transparietal needle aspiration. Different classifications have been proposed for PIP. Either medical, radiation or surgical therapy has been used for PIP. Whenever possible, surgery should be considered the standard treatment. Complete surgical resection is advocated to prevent recurrence.</p
Relationship between fibroblastic foci profusion and high resolution CT morphology in fibrotic lung disease
Cranial Nerves VII To VIII
Cranial nerves VII and VIII are easily visualized within cerebrospinal fluid (CSF) in most patients and are the nerves most commonly involved with neurogenic neoplasms. The reasons for performing contrast‐enhanced scans are explained in this unit, but revolve around pathologies other than schwannomas of the nerves.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145305/1/cpmia0703.pd
Age differences in orbitofrontal activation: an fMRI investigation of delayed match and nonmatch to sample
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