Evaluation of Compressed SENSE on Image Quality and Reduction of MRI Acquisition Time: A Clinical Validation Study.

RATIONALE AND OBJECTIVES: To evaluate the effect of compressed SENSE (CS) in clinical settings on scan time reduction and image quality. MATERIALS AND METHODS: Ninety-five magnetic resonance imaging (MRI) scans from different anatomical regions were acquired, consisting of a standard protocol sequence (SS) and sequence accelerated with CS. Anonymized paired sequences were randomly displayed and rated by six blinded subspecialty radiologists. Side-by-side evaluation on perceived sharpness, perceived signal-to-noise-ratio (SNR), lesion conspicuity, and artifacts were compared and scored on a five-point Likert scale, and individual image quality was evaluated on a four-point Likert scale. RESULTS: CS reduced overall scan time by 32% while maintaining acceptable MRI quality for all regions. The largest time savings were seen in the spine (mean = 68 seconds, 44% reduction) followed by the brain (mean = 86 seconds, 37% reduction). The sequence with maximum time savings was intracranial 3D-time-of-flight magnetic resonance angiography (202 seconds, 56% reduction). CS was mildly inferior to SS on perceived sharpness, perceived SNR, and lesion conspicuity (mean scores = 2.32-2.96, P < .001 [1: SS superior; 3: equivalent; 5: CS superior]). CS was equivalent to SS for joint and body scans on overall image quality (CS = 3.02-3.37, SS = 3.04-3.68, P > .05, [1: lowest quality and 4: highest quality]). The overall image quality of CS was slightly less for brain and spine scans (mean CS = 2.79-3.05, mean SS = 3.13-3.43, P = .021) but still diagnostic. Good overall clinical acceptance for CS (88%) was noted with full clinical acceptance for body scans (100%) and high acceptance for other regions (68%-95%). CONCLUSION: CS significantly reduced MR acquisition time while maintaining acceptable image quality. The implementation of CS may improve departmental workflows and enhance patient care.

Large solitary lytic skull vault lesions in adults: radiological review with pathological correlation.

The diagnosis of a large solitary lytic skull vault lesion in adults is a challenge due to variable aggressiveness and overlapping features. The purpose of this article is to demonstrate the use of an imaging approach to narrow the differential diagnosis when a large solitary lytic skull vault lesion is encountered. The initial imaging assessment using computed tomography (CT) is invaluable in determining lesion aggressiveness based on bony margins and skull tables involvement. Further assessment with magnetic resonance (MR) imaging including diffusion weighted imaging (DWI) aids in soft tissue characterization. We present cases of large solitary lytic skull vault lesions in adults, emphasizing on salient and atypical imaging features, with pathological correlation for better understanding of the disease processes that underlie the imaging features.

The pancreatic and extrapancreatic manifestations of IgG4-related disease.

The association between immunoglobulin IgG4 and autoimmune pancreatitis was first shown in 2001. Since then many previously established fibrosclerotic diseases demonstrating synchronous or metachronous multiorgan involvement have been included within the ambit of IgG4-related disease. Diagnostic criteria have been proposed involving 1) serum IgG4 level elevated beyond 135 mg/dL, 2) IgG4+ to IgG+ plasma cell ratio > 40% and >10 IgG4+ cells per high power field of biopsy sample and 3) a constellation of imaging features which involve a variety of organ systems. We present a pictorial essay demonstrating the spectrum of imaging findings for IgG4-related disease, including dacryosialadenitis, variety of renal lesions, tumefactive thickening of the extraocular muscles and orbital nerve, sclerosing cholangitis, and type I pancreatitis. Imaging plays an important role in diagnosis, screening for multiorgan involvement, and follow-up of the disease.

Clinicoradiologic features distinguish tumefactive multiple sclerosis from CNS neoplasms.

BACKGROUND: There are limited data to guide clinicians in differentiating tumefactive multiple sclerosis (TMS) from CNS neoplasms. Identifying distinguishing features will inform diagnosis and management and avoid unnecessary diagnostic biopsy. Our study aimed to determine the clinical and radiologic features that differentiate TMS from glioma and CNS lymphoma (CNSL) in patients who present with tumefactive lesions. METHODS: We retrospectively reviewed all patients with tumefactive lesions and histologically proven or clinically diagnosed TMS, glioma, or CNSL at our tertiary center from 1999 to 2012. Two independent blinded neuroradiologists rated MRI brain scans at presentation. We correlated patients' demographic, clinical, laboratory, and radiologic data to final diagnosis. RESULTS: A total of 133 patients (10 TMS, 85 glioma, 38 CNSL) were analyzed. Patients with TMS were younger and a greater proportion were women. Presenting symptoms did not distinguish between diagnoses. TMS lesions were smaller compared to glioma and CNSL, had no or mild mass effect, and were always associated with contrast enhancement. Radiologic features that were more frequent in TMS lesions were incomplete rim (open-ring) enhancement, incomplete peripheral diffusion restriction, and mixed T2 signal and CT hypoattenuation of MRI-enhancing components (all p < 0.05). CONCLUSIONS: Radiologic features but not presenting symptoms are useful in distinguishing TMS from CNS neoplasms.

[A young woman with progressive cerebral atrophy]. / Een jonge vrouw met progressieve cerebrale atrofie.

A 21-year-old patient suffering from neurofibromatosis type 1 had received radiotherapy for a chiasm glioma 17 years ago. Fourteen years later, there was progressive deterioration of several neurological functions. MRI scans showed a progressively increasing volume loss of the left hemisphere and stenoses around the circle of Willis with secondary parenchymal effects. Based on conventional cerebral angiography, the diagnosis 'moyamoya syndrome' was made.

Hypoxic-ischaemic brain injury in young infants.

Many imaging techniques are available for the detection of hypoxic-ischaemic brain injury in young infants.This paper presents an overview of the imaging fi ndings in hypoxic-ischaemic brain injury with an emphasis on MR imaging.

Comparing brain white matter on sequential cranial ultrasound and MRI in very preterm infants.

INTRODUCTION: Periventricular white matter (WM) echodensities, frequently seen in preterm infants, can be associated with suboptimal neurodevelopment. Major WM injury is well detected on cranial ultrasound (cUS). cUS seems less sensitive for diffuse or more subtle WM injury. Our aim was to assess the value of cUS and magnetic resonance imaging (MRI) for evaluating WM changes and the predictive value of cUS and/or MRI findings for neurodevelopmental outcome in very preterm infants with normal to severely abnormal WM on sequential high-quality cUS. MATERIALS AND METHODS: Very preterm infants (<32 weeks) who had sequential cUS and one MRI within the first three postnatal months were included. Periventricular WM on cUS and MRI was compared and correlated with neurodevelopmental outcome at 2 years corrected age. RESULTS: Forty preterm infants were studied; outcome data were available in 32. WM changes on sequential cUS were predictive of WM changes on MRI. Severely abnormal WM on cUS/MRI was predictive of adverse outcome, and normal-mildly abnormal WM of favorable outcome. Moderately abnormal WM on cUS/MRI was associated with variable outcome. Additional MRI slightly increased the predictive value of cUS in severe WM changes. CONCLUSION: Sequential cUS in preterm infants is reliable for detecting WM changes and predicting favorable and severely abnormal outcome. Conventional and diffusion-weighted MRI sequences before term equivalent age in very preterm infants, suggested on cUS to have mild to moderately abnormal WM, do not seem to be warranted.

Hypoxic-ischemic encephalopathy: diagnostic value of conventional MR imaging pulse sequences in term-born neonates.

PURPOSE: To retrospectively compare different magnetic resonance (MR) imaging techniques and pulse sequences for the depiction of brain injury in neonatal hypoxic-ischemic encephalopathy. MATERIALS AND METHODS: The institutional review board approved this retrospective study and waived informed consent. Term-born neonates underwent MR imaging within 10 days after birth because of perinatal asphyxia. Two investigators separately and retrospectively evaluated T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted, and T1-weighted contrast material-enhanced MR images for presence of hypoxic-ischemic injury patterns. Interobserver agreement between the raters for visualizing abnormalities on images obtained with the individual pulse sequences was analyzed. Individual assessments were compared with the consensus reading (reference standard) to determine which techniques were best for visualizing hypoxic-ischemic damage. Last, which combination of pulse sequences had the best performance for visualizing certain injury patterns was evaluated. All analyses were repeated for infants imaged within 4 days after birth and those imaged between 4 and 10 days after birth. RESULTS: Forty term-born neonates (22 boys; gestational age, 37 weeks to 42 weeks 2 days) were included. Interobserver agreement was moderate for all pulse sequences (intraclass correlation coefficient [ICC], 0.52-0.73). As compared with the reference standard, T1-weighted imaging performed best in both groups (infants imaged < or = 4 days and those imaged > 4 days after birth) for lesions in the basal ganglia, thalamus, and posterior limb of the internal capsule (ICC, 0.93), as well as for punctate white matter lesions (ICC, 0.88). For infarction, diffusion-weighted images were scored best in both groups (ICC, 0.86). For nonpunctate white matter lesions, T2-weighted images were scored as good in both groups (ICC, 0.59). Adding FLAIR and contrast-enhanced imaging to the combination of T1- and T2-weighted imaging and diffusion-weighted imaging did not contribute to detection of hypoxic-ischemic brain damage. CONCLUSION: The combination of T1- and T2-weighted MR imaging and diffusion-weighted imaging is best for detecting hypoxic-ischemic brain lesions in the early neonatal period in term-born infants.

Differentiation between peritrigonal terminal zones and hypoxic-ischemic white matter injury on MRI.

The differentiation between terminal zones and pathological signal intensity changes on MRI of children and young adults is of diagnostic importance. We assessed the diagnostic value of several morphological features on MRI to differentiate between terminal zones and hypoxic-ischemic white matter injury. We selected all brain MRI examinations performed in subjects up to 20 years of age showing increased signal intensity on T2-weighted images in the peritrigonal areas. 75 individuals were assigned to a patient group (n=28) if there was evidence of hypoxia-ischemia during the perinatal period or a control group (n=47). Aspect, location, extent, shape, and borders of signal intensity changes in the peritrigonal areas were studied. Signal intensity of the peritrigonal areas was related to signal intensity of surrounding white matter. Presence of Virchow Robin spaces, hypoxic-ischemic abnormalities, and local atrophy were also recorded. Chi-squared tests assessed whether presence or absence of morphological characteristics differed between patients and controls. Logistic regression analysis studied which characteristics were best to discriminate between the two groups. Very high signal intensity of the peritrigonal areas on FLAIR (Odds Ratio 25) and presence of local atrophy (Odds Ratio 14.3) were best predictors to discriminate between the two groups.

MRI supported diagnosis and counselling in a family with a probably autosomal recessive form of pachygyria.

OBJECTIVES: To describe the use of fetal MRI as an adjunct to high-resolution ultrasound in parental counselling in a family with a central nervous system (CNS) abnormality, resembling the agyria-pachyria complex, of probably autosomal recessive inheritance. METHODS: Description of the use of fetal MRI as an adjunct to high-resolution ultrasound in three consecutive pregnancies in a family with a CNS abnormality. RESULTS: Fetal MRI, by showing more detailed abnormalities of the CNS, proved to be very useful in parental counselling because of the definitive diagnosis available early in pregnancy. In the first two pregnancies, ultrasound examination revealed mild pyelectasis, megacystis and an enlarged posterior fossa with small cerebellum. MRI at 22-33 weeks confirmed these abnormalities, but also showed pachygyria. In the third pregnancy, MRI at 19 weeks showed no abnormalities, a finding of decisive importance for counselling. CONCLUSION: Fetal MRI was useful both for early diagnosis and prenatal management in this family with an agyria-pachyria complex CNS abnormality.

The value of MR angiography techniques in the detection of head and neck paragangliomas.

OBJECTIVE: The objective of this study was to compare three-dimensional phase-contrast angiography (3D PCA), 2D time-of-flight (2D TOF), and 3D TOF magnetic resonance (MR) angiography and a proton density weighted technique in terms of their ability to detect head and neck paragangliomas. MATERIALS AND METHODS: 14 patients with 29 paragangliomas were examined at 1.5 T. Three MR angiography sequences (3D PCA, 2D TOF, and multi-slab 3D TOF) and a proton density (PD) weighted sequence were reviewed by four neuroradiologists. The gold standard was digital subtraction angiography. Presence of tumor was assessed in five grades of confidence. Sensitivity and specificity were calculated after dichotomizing the results. Data was analyzed using the logistic regression method. RESULTS: Mean sensitivity and specificity for the four observers were for PD: 72%/97%, for 3D PCA: 75%/90%, for 2D TOF: 66%/93%, and for 3D TOF: 90%/92%. Sensitivity was significantly better for 3D TOF MRA (P < 0.001). No substantial between-observer variation for tumor detection was present. CONCLUSION: Our results demonstrate that, using 3D TOF MRA, paragangliomas in the head and neck region can be detected with high sensitivity and specificity. Further investigation is necessary to judge the value of 3D TOF MR angiography against fat suppressed contrast enhanced T1 weighted and fat suppressed T2 weighted MR sequences to find the optimal imaging sequence for paragangliomas.