SUMMARY:Although the combination of MR imaging findings and clinical evidence of hypertension may suggest the diagnosis of posterior reversible encephalopathy syndrome (PRES), MR imaging findings with only involvement of the medulla oblongata pose a diagnostic dilemma. In the cases presented here, we demonstrated MR imaging findings of a presumed brain stem (medulla oblongata) variant of PRES and emphasized the diagnostic value of diffusion-weighted imaging (DWI). Posterior reversible encephalopathy syndrome (PRES) is characterized by headache, vomiting, altered consciousness, seizure, and cortical blindness associated with imaging findings of predominantly posterior bilateral symmetric subcortical and cortical edema without frank infarction.1 Hyperintense lesions on T2-weighted MR imaging and swelling of the brain stem may be related to many different pathologic processes. PRES rarely presents with predominant involvement of the brain stem, and involvement of only the medulla oblongata is uncommon.2,3 Only 1 patient with PRES was reported to have medulla oblongata, upper cervical spinal cord, and supratentorial involvement. 4 Herein we report 2 cases of a presumed variant of PRES with only medulla oblongata involvement. Case Reports Case 1A 59-year-old man with history of left putaminal hemorrhage 15 years previously had a 1-week history of poor appetite, vomiting, altered consciousness, and seizure-like movements. His history was also significant for hypertension controlled with medications. Initial blood pressure (BP) was 210/108 mm Hg. Serum electrolytes were normal. Brain MR imaging (Signa LX2; GE Healthcare, Milwaukee, Wis) revealed isointensity on T1-weighted images (T1WIs) and diffusionweighted images (DWIs), and hyperintensity on T2-weighted images (T2WIs) of the medulla oblongata and upper cervical spinal cord (Fig 1). Because of clinical signs and history and MR imaging findings of edema (not infarction) in the medulla oblongata and upper cervical spinal cord, the differential diagnosis included a variant of PRES, encephalitis, and encephalomyelitis. Because there was no evidence of infection or fever, and results on CSF examination were unremarkable, a variant of PRES was the likely diagnosis. An angiotensinconverting enzyme inhibitor and a calcium channel blocker were administered for BP control. His clinical condition improved, BP normalized to 140/90 mm Hg, and level of consciousness returned to normal. MR imaging 45 days later (Fig 1) indicated resolution of hyperintensity confirming a variant of PRES secondary to hypertension with involvement of the medulla oblongata. Case 2A 62-year-old man with a history of hypertension and cerebral infarction was seen with a 3-day history of headache, vomiting, involuntary movement, and change in consciousness. BP was 180/100 mm Hg. No signs of infection or a meningeal abnormality were present, and serum electrolyte levels and CSF were normal. Brain MR imaging showed hyperintensity on T2WIs and isointensity on DWIs, which involved the medulla oblongata (Fig ...

BACKGROUND AND PURPOSE: High-resolution vessel wall MR imaging is prone to slow-flow artifacts, particularly when gadolinium shortens the T1 relaxation time of blood. This study aimed to determine the optimal preparation pulses for contrast-enhanced high-resolution vessel wall MR imaging. MATERIALS AND METHODS:Fifty patients who underwent both motion-sensitized driven equilibrium and delay alternating with nutation for tailored excitation (DANTE) preparation pulses with contrast-enhanced 3D-T1-FSE were retrospectively included. Qualitative analysis was performed using a 4-grade visual scoring system for black-blood performance in the small-sized intracranial vessels, overall image quality, severity of artifacts, and the degree of blood suppression in all cortical veins as well as transverse sinuses. Quantitative analysis of the M1 segment of the MCA was also performed. RESULTS:The qualitative analysis revealed that motion-sensitized driven equilibrium demonstrated a significantly higher black-blood score than DANTE in contrast-enhanced 3D-T1-FSE of the A3 segment (3.90 versus 3.58, P , .001); M3 (3.72 versus 3.26, P = .004); P2 to P3 (3.86 versus 3.64, P = .017); the internal cerebral vein (3.72 versus 2.32, P , .001); and overall cortical veins (3.30 versus 2.74, P , .001); and transverse sinuses (2.82 versus 2.38, P , .001). SNR lumen , contrast-to noise ratio wall-lumen , and SNR wall in the M1 vessel were not significantly different between the 2 preparation pulses (all, P . .05).CONCLUSIONS: Motion-sensitized driven equilibrium demonstrated improved blood suppression on contrast-enhanced 3D-T1-FSE in the small intracranial arteries and veins compared with DANTE. Motion-sensitized driven equilibrium is a useful preparation pulse for high-resolution vessel wall MR imaging to decrease venous contamination and suppress slow-flow artifacts when using contrast enhancement.ABBREVIATIONS: BB ¼ black-blood; CE ¼ contrast-enhanced; CNR ¼ contrast-to-noise ratio; DANTE ¼ delay alternating with nutation for tailored excitation; HR-VWI ¼ high-resolution vessel wall MR imaging; ICV ¼ internal cerebral vein; MSDE ¼ motion-sensitized driven equilibrium

BACKGROUND AND PURPOSE: Contrast-enhanced 3D-turbo spin-echo (TSE) black-blood sequence has gained attention, as it suppresses signals from vessels and provides an increased contrast-noise ratio. The purpose was to investigate which among the contrast-enhanced 3D T1 TSE, 3D T1 fast-spoiled gradient echo (FSPGR), and 3D T2 FLAIR sequences can better detect cranial nerve contrast enhancement. MATERIALS AND METHODS:Patients with cranial neuritis based on clinical findings (n ¼ 20) and control participants (n ¼ 20) were retrospectively included in this study. All patients underwent 3T MR imaging with contrast-enhanced 3D T1 TSE, 3D T1 FSPGR, and 3D T2 FLAIR. Experienced and inexperienced reviewers independently evaluated the 3 sequences to compare their diagnostic performance and time required to reach the diagnosis. Additionally, tube phantoms containing varying concentrations of gadobutrol solution were scanned using the 3 sequences.

Purpose To compare the diagnostic accuracies of renal ultrasonography (US) and voiding cystourethrography (VCUG) for vesicoureteral reflux (VUR). Materials and MethodsThis retrospective study included infants and children (< 24 months of age) with urinary tract infections who underwent renal US and VCUG. The incidences of decreased or increased renal size, increased renal parenchymal echogenicity, ureteral dilation, ureteral wall thickening, renal pelvic dilation, pelvic wall thickening, and accentuated pelvic dilation in the prone position were compared. Grade 3 or higher VUR was classified as "highgrade." A total of 138 patients (109 males; mean age, 3 months) were included. Multivariate logistic regression analysis was performed, and diagnostic accuracy was calculated.Results Fifty-three (38.4%) and 43 (31.2%) patients exhibited all-grade and high-grade VUR. Decreased renal size was significantly related to all-grade [odds ratio (OR): 16.6; 95% confidence interval (CI): 3.4-81.3; p = 0.001) and high-grade VUR (OR: 29.7; 95% CI: 5.7-155.3; p < 0.001). Accentuated pelvic dilation in the prone position, increased renal parenchymal echogenicity, and ureteral dilation were related to all-grade and high-grade VUR. ConclusionDecreased renal size showed the highest diagnostic accuracy for US-based diagnosis of all-grade and high-grade VUR. Accentuated pelvic dilation in the prone position, increased renal parenchymal echogenicity, and ureteral dilation may aid in the diagnosis of high-grade VUR.

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