Publications by authors named "Juan Pablo Villablanca"

4 Publications

  • Page 1 of 1

Advanced Imaging in the Evaluation of Migraine Headaches.

Neuroimaging Clin N Am 2019 May 19;29(2):301-324. Epub 2019 Feb 19.

Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Boulevard, Suite 615, Los Angeles, CA 90024, USA.

The use of advanced imaging in routine diagnostic practice appears to provide only limited value in patients with migraine who have not experienced recent changes in headache characteristics or symptoms. However, advanced imaging may have potential for studying the biological manifestations and pathophysiology of migraine headaches. Migraine with aura appears to have characteristic spatiotemporal changes in structural anatomy, function, hemodynamics, metabolism, and biochemistry, whereas migraine without aura produces more subtle and complex changes. Large, controlled, multicenter imaging-based observational trials are needed to confirm the anecdotal evidence in the literature and test the scientific hypotheses thought to underscore migraine pathophysiology.
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May 2019

Periprocedural arterial spin labeling and dynamic susceptibility contrast perfusion in detection of cerebral blood flow in patients with acute ischemic syndrome.

Stroke 2013 Mar 6;44(3):664-70. Epub 2013 Feb 6.

Department of Medical Imaging, University of Arizona Medical Center, Tucson, AZ 85724-5067, USA.

Background And Purpose: To compare the diagnostic performance of arterial spin-labeling (ASL) and dynamic susceptibility contrast (DSC) perfusion in detecting cerebral blood flow (CBF) changes before and after endovascular recanalization in acute ischemic syndrome.

Methods: The inclusion criteria for this retrospective study were patients with acute ischemic syndrome who underwent endovascular recanalization and acquisition of both ASL and DSC before and after revascularization. ASL-CBF and multiparametric DSC maps were evaluated for image quality, location, and type of perfusion abnormality. Relative CBF (rCBF) was calculated in the infarction core and hypoperfused areas using coregistered ASL and DSC. Core and hypoperfused rCBF were used for paired pretreatment and posttreatment comparisons. Interobserver and intermodality agreement were evaluated by κ test, and t test was calculated for ASL and DSC rCBF values.

Results: Twenty-five patients met our inclusion criteria. Five studies were rated nondiagnostic, resulting in 45 pairs of DSC-ASL available for comparison. ASL and DSC agreed on type and location of the perfusion abnormality in 71% and 80% of cases, respectively. The image quality of ASL was lower than DSC, resulting in interobserver variability for the type (κ=0.45) and location (κ=0.56) of perfusion abnormality. ASL was unable to show any type of perfusion abnormality in 11% of patients. In successfully recanalized patients, hyperperfusion (rCBF >1) was detected in 100% on DSC and 47% on ASL.

Conclusions: ASL is less sensitive than DSC for detecting rCBF changes in patients with acute ischemic syndrome, particularly with respect to hyperperfusion after successful recanalization.
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March 2013

Ten-year experience with nephrogenic systemic fibrosis: case-control analysis of risk factors.

J Comput Assist Tomogr 2009 Nov-Dec;33(6):819-23

Department of Radiological Sciences, Ronald Reagan UCLA Medical Center, Los Angeles, CA 90095-7437, USA.

Objectives: To analyze all cases of nephrogenic systemic fibrosis (NSF) at our institution and to compare them with controls.

Methods: After the institutional review board approval, 13 biopsy-proven NSF cases were identified. Ten cases had complete records and were compared in a case-control format with 10 age- and sex-matched, dialysis-dependent controls. Analyzed risk factors included single and cumulative gadolinium dose, medication and transplant history, and serum electrolytes at the time of gadolinium exposure.

Results: There were 1.9% of dialysis-dependent, gadolinium-exposed patients who developed NSF. There was no difference in gadolinium dose, transplant history, or serum electrolytes. Seven of 10 cases and 3 of 10 controls were treated with erythropoietin (P = 0.13). At the time of NSF diagnosis, 7 of 10 cases were on immunosuppressive therapy. Two of 7 cases developed NSF only after immunosuppressive therapy was initiated. Two of 10 controls were on immunosuppressive therapy (P = 0.06).

Conclusions: All cases of NSF occurred in dialysis-dependent, gadolinium-exposed patients. Associations between immunosuppressive and erythropoietin therapies and NSF need further investigation.
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January 2010

Endonasal transsphenoidal transclival removal of prepontine epidermoid tumors: technical note.

Neurosurgery 2005 Apr;56(2 Suppl):E443; discussion E443

Division of Neurosurgery, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA.

Objective: Prepontine retroclival tumors have typically been removed through a variety of anterolateral, lateral, and posterolateral cranial base approaches. Here, we describe an endonasal transclival cranial base approach for removal of prepontine epidermoid tumors.

Methods: Two men, 40 and 52 years old, each presented with a history of headaches and cranial nerve deficits. In each patient, magnetic resonance imaging showed a large T1 hypointense/T2 hyperintense mass occupying the posterior suprasellar, premesencephalic, and prepontine cisterns, with significant mass effect on the brainstem. Both patients underwent an endonasal transsphenoidal transclival cranial base tumor removal with the operating microscope and endoscopic assistance. The dural and bony defects were repaired with abdominal fat grafts, collagen sponge, titanium mesh, and cerebrospinal fluid diversion. One patient developed a postoperative cerebrospinal fluid leak and meningitis requiring two reoperations to repair, ultimately with fat and fascia lata grafts.

Results: At 1 year after surgery, both patients have improved compared with their preoperative neurological state, and volume analysis of preoperative and 1-year postoperative magnetic resonance imaging scans confirm a marked reduction in mass effect on the brainstem, with a 78% tumor removal in one patient and 76% removal in the other. Both patients have normal endocrine function.

Conclusion: The endonasal approach offers a minimally invasive, anatomically direct route for removing prepontine epidermoid tumors that obviates brain retraction. The use of angled endoscopes is essential for gaining lateral, cephalad, and caudal visualization to augment the limited microscope view. Inadequate repair of clival dural defects remains the greatest potential pitfall in attempting transsphenoidal transclival tumor removal.
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April 2005