Uncovering neuroanatomical correlates of impaired coordinated movement after pallidal deep brain stimulation.

BACKGROUND: The loss of the ability to swim following deep brain stimulation (DBS), although rare, poses a worrisome risk of drowning. It is unclear what anatomic substrate and neural circuitry underlie this phenomenon. We report a case of cervical dystonia with lost ability to swim and dance during active stimulation of globus pallidus internus. We investigated the anatomical underpinning of this phenomenon using unique functional and structural imaging analysis. METHODS: Tesla (3T) functional MRI (fMRI) of the patient was used during active DBS and compared with a cohort of four matched patients without this side effect. Structural connectivity mapping was used to identify brain network engagement by stimulation. RESULTS: fMRI during stimulation revealed significant (Pbonferroni<0.0001) stimulation-evoked responses (DBS ON

Lesion network mapping of ectopic craniopharyngioma identifies potential cause of psychosis: a case report.

We report the case of a patient with craniopharyngioma who demonstrated ectopic spread to the right temporal lobe and concurrent local recurrence, 10 years after her initial diagnosis. The patient additionally demonstrated new-onset psychotic symptoms of uncertain etiology during her admission. Lesion network mapping identified the ectopic lesion as a putative cause for her psychosis. These findings were substantiated after the resection of the ectopic lesion and subsequent resolution of her psychiatric symptoms. This report adds to the rare accounts of ectopic craniopharyngioma, while highlighting the utility of network-based analyses in peri-operative tumor evaluation and the assessment of atypical neuropsychiatric phenomena.

Successful Endovascular Management of Resistant Hypertension Post Kidney Transplant: A Case Report.

Rationale: Transplant renal artery stenosis (TRAS) is a well-recognized and potentially reversible cause of resistant hypertension post transplantation and can affect 1% to 23% of recipients. Stenosis of the iliac segment proximal to the transplant renal artery (proximal TRAS) causing dysfunction of the transplanted kidney is less common with reported incidence of 2% to 3%. Presentation typically occurs between 3 months and 2 years post transplant but may happen at any time. Noninvasive investigations such as Doppler ultrasound, computed tomography (CT) angiogram, and magnetic resonance angiogram are useful in initial evaluation, but definitive diagnosis of hemodynamically significant stenosis often requires formal angiogram. Transplant renal artery stenosis should be suspected in any kidney transplant recipient with worsening hypertension and/or deterioration in kidney function which is otherwise unexplained. We present the case of a kidney transplant recipient with resistant hypertension and impaired graft function, secondary to severe impairment of graft blood flow from proximal iliac system occlusion. Presenting concerns of the patient: A 74-year-old female 15 years post live donor kidney transplant presented with graft dysfunction (serum Cr 229 µmol/L) and resistant hypertension, requiring use of 8 antihypertensive medications. On physical examination, blood pressure was 160/92 mm Hg with no tenderness over the renal graft in the right lower abdominal quadrant and no audible bruit in kidney allograft area. Diagnosis: Transplant Doppler ultrasound showed reversal of flow in the right external iliac artery suggestive of ipsilateral proximal iliac occlusion. Pre-procedure CT demonstrated severe atherosclerotic burden within the aorta and bilateral iliac systems. The anastomosed right renal artery appeared patent. Interventions: Conventional angiogram showed occlusion of the right common and proximal external iliac arteries with retrograde perfusion of the transplant kidney via the contralateral left iliac system and aorta. Subintimal recanalization of the right iliac system was performed with angioplasty and kissing stent placement at the aortic bifurcation with stents extending into the proximal right external iliac artery. Post deployment angiogram demonstrated renewed patency of the right iliac system, with restoration of antegrade perfusion to the transplant kidney. Outcomes: The patient's blood pressure decreased significantly after the procedure, with improvement in graft function. After 6 months, the patient continued to have optimally controlled blood pressure (on 3 medications) and stable graft function (serum Cr 74 µmol/L). Teaching points: Our case describes proximal TRAS and the contribution of renal hypoperfusion to hypertension and impaired graft function, with the potential for reversibility.

Justification: La sténose de l'artère du rein transplanté (SART) est une cause bien connue et potentiellement réversible d'hypertension résistante qui touche de 1 à 23% des receveurs après l'intervention. La sténose du segment iliaque proximal de l'artère du rein transplanté (SARTprox), laquelle cause un dysfonctionnement du greffon, est moins fréquente (incidence rapportée: 2 à 3%). Elle se produit généralement entre 3 mois et 2 ans après la transplantation, mais peut se produire à tout moment. Les examens non invasifs tels que l'échographie Doppler, l'angiographie par tomodensitométrie (TDM) et l'angiographie par résonance magnétique sont utiles pour l'évaluation initiale, mais le diagnostic définitif d'une sténose hémodynamiquement significative nécessite souvent une angiographie formelle. Les SART doivent être suspectées chez tout receveur d'une greffe rénale présentant une aggravation de l'hypertension et/ou une détérioration de la fonction rénale, autrement inexpliquées. Nous présentons le cas d'une receveuse souffrant d'hypertension résistante et d'une altération de la fonction du greffon résultant d'une grave altération du flux sanguin dans le greffon causée par l'occlusion du système iliaque proximal. Présentation du cas: Une femme de 74 ans, greffée 15 ans auparavant avec un rein de donneur vivant, présentait un dysfonctionnement du greffon (Cr sérique: 229 µmol/L) et une hypertension résistante nécessitant huit médicaments antihypertenseurs. À l'examen physique, la pression artérielle était de 160/92 mm Hg et la patiente ne présentait aucune sensibilité au-dessus du greffon rénal dans le quadrant inférieur droit de l'abdomen, ni bruit audible au niveau de l'artère rénale. Diagnostic: L'échographie Doppler du greffon a montré une inversion du flux dans l'artère iliaque externe droite, ce qui suggérait une occlusion iliaque proximale ipsilatérale. La TDM avant l'intervention avait montré une charge athérosclérotique sévère dans l'aorte et les systèmes iliaques bilatéraux. L'artère rénale droite anastomosée semblait non obstruée. Intervention: L'angiographie conventionnelle a montré une occlusion de l'artère iliaque commune droite et de l'artère iliaque externe proximale, avec une perfusion rétrograde du rein transplanté via le système iliaque gauche controlatéral et l'aorte. La recanalisation sous-intimale du système iliaque droit a été réalisée par angioplastie et on a procédé à la pose d'une endoprothèse au niveau de la bifurcation aortique avec des extenseurs s'étendant dans l'artère iliaque externe droite proximale. L'angiographie post-déploiement a démontré une perméabilité renouvelée du système iliaque droit, avec restauration de la perfusion antérograde vers le rein transplanté. Résultats: Après la procédure, la pression artérielle de la patiente s'est abaissée significativement et la fonction du greffon s'est améliorée. Après 6 mois, la pression artérielle demeurait bien contrôlée (avec trois médicaments) et la fonction du greffon était stable (Cr sérique: 74 µmol/L). Enseignements tirés: Notre cas décrit une SARTprox et la contribution de l'hypoperfusion rénale à l'hypertension et à l'altération de la fonction du greffon, avec un potentiel de réversibilité.

Identifying Thrombus on Non-Contrast CT in Patients with Acute Ischemic Stroke.

The hyperdense sign is a marker of thrombus in non-contrast computed tomography (NCCT) datasets. The aim of this work was to determine optimal Hounsfield unit (HU) thresholds for thrombus segmentation in thin-slice non-contrast CT (NCCT) and use these thresholds to generate 3D thrombus models. Patients with thin-slice baseline NCCT (≤2.5 mm) and MCA-M1 occlusions were included. CTA was registered to NCCT, and three regions of interest (ROIs) were placed in the NCCT, including: the thrombus, contralateral brain tissue, and contralateral patent MCA-M1 artery. Optimal HU thresholds differentiating the thrombus from non-thrombus tissue voxels were calculated using receiver operating characteristic analysis. Linear regression analysis was used to predict the optimal HU threshold for discriminating the clot only based on the average contralateral vessel HU or contralateral parenchyma HU. Three-dimensional models from 70 participants using standard (45 HU) and patient-specific thresholds were generated and compared to CTA clot characteristics. The optimal HU threshold discriminating thrombus in NCCT from other structures varied with a median of 51 (IQR: 49-55). Experts chose 3D models derived using patient-specific HU models as corresponding better to the thrombus seen in CTA in 83.8% (31/37) of cases. Patient-specific HU thresholds for segmenting the thrombus in NCCT can be derived using normal parenchyma. Thrombus segmentation using patient-specific HU thresholds is superior to conventional 45 HU thresholds.