Pituitary MRI standard and advanced sequences: role in the diagnosis and characterization of pituitary adenomas

2021 ◽  
Author(s):  
Mônica R Gadelha ◽  
Monique Alvares Barbosa ◽  
Elisa Baranski Lamback ◽  
Luiz Eduardo Wildemberg ◽  
Leandro Kasuki ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Pituitary Adenomas ◽  
Imaging Modality ◽  
Spin Echo ◽  
Sella Turcica ◽  
Fast Spin Echo ◽  
Standard Protocol ◽  
Cavernous Sinus Invasion ◽  
Mri Features

Abstract Pituitary adenomas (PAs) represent the most frequently found lesions in the sellar region; however, several other lesions may be encountered in this region, such as meningiomas, craniopharyngiomas and aneurysms. High-quality imaging is fundamental for diagnosis, characterization and guidance of treatment planning of PAs. Sellar magnetic resonance imaging (MRI) is considered the imaging modality of choice for the evaluation of lesions in the sella turcica. The sellar MRI standard protocol includes coronal and sagittal T1-weighted (T1w) spin-echo sequencing with and without gadolinium-based contrast agent and coronal T2-weighted (T2w) fast-spin echo sequencing. A systematic MRI approach to the pituitary region generally provides information that includes the size and shape of the PA, the presence of cysts or hemorrhage within the tumor, its relationship with the optic pathways and surrounding structures, potential cavernous sinus invasion, sphenoid sinus pneumatization type, and differential diagnosis with other sellar lesions. The standard protocol is sufficient for the evaluation of most cases; however, some advanced techniques (susceptibility imaging, diffusion-weighted imaging, 3D T2w high-resolution sequences, magnetic resonance elastography, perfusion-weighted imaging) may render additional information, which may be important for some cases. In this “Approach to the Patient” manuscript we will discuss the use of standard and advanced MRI sequences in the diagnosis and characterization of PAs, including MRI features associated with treatment response that may aid in presurgical evaluation and planning, and red flags that may point to an alternative diagnosis.

Most commonly used sequences and clinical protocols for brain and spine magnetic resonance imaging allowing better identification of pathological changes in dogs

2013 ◽  
Vol 16 (1) ◽  
pp. 157-163 ◽  
Author(s):  
Y. Zhalniarovich ◽  
Z. Adamiak ◽  
A. Pomianowski ◽  
M. Jaskólska
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Imaging Modality ◽  
Spin Echo ◽  
Inversion Recovery ◽  
Fast Spin Echo ◽  
Single Shot ◽  
Turbo Spin Echo ◽  
Resonance Imaging ◽  
Turbo Spin

Abstract Magnetic resonance imaging is the best imaging modality for the brain and spine. Quality of the received images depends on many technical factors. The most significant factors are: positioning the patient, proper coil selection, selection of appropriate sequences and image planes. The present contrast between different tissues provides an opportunity to diagnose various lesions. In many clinics magnetic resonance imaging has replaced myelography because of its noninvasive modality and because it provides excellent anatomic detail. There are many different combinations of sequences possible for spinal and brain MR imaging. Most frequently used are: T2-weighted fast spin echo (FSE), T1- and T2-weighted turbo spin echo, Fluid Attenuation Inversion Recovery (FLAIR), T1-weighted gradient echo (GE) and spin echo (SE), high-resolution three-dimensional (3D) sequences, fat-suppressing short tau inversion recovery (STIR) and half-Fourier acquisition single-shot turbo spin echo (HASTE). Magnetic resonance imaging reveals neurologic lesions which were previously hard to diagnose antemortem.

Ultra high resolution nonenhanced fast spin echo magnetic resonance imaging: Cost-effective screening for acoustic neuroma in patients with sudden sensorineural hearing loss

1998 ◽  
Vol 119 (4) ◽  
pp. 364-369 ◽  
Author(s):  
Robert L. Daniels ◽  
Clough Shelton ◽  
H. Ric Harnsberger
Keyword(s):  
Magnetic Resonance Imaging ◽  
Hearing Loss ◽  
Magnetic Resonance ◽  
Sensorineural Hearing Loss ◽  
Acoustic Neuroma ◽  
Spin Echo ◽  
Sudden Sensorineural Hearing Loss ◽  
Fast Spin Echo ◽  
Resonance Imaging ◽  
Fast Spin

The financial burden for the evaluation of patients for acoustic neuroma in an otolaryngology practice is substantial. Patients with sudden sensorineural hearing loss represent a portion of that population seen with unilateral, asymmetric auditory symptoms who require investigation for acoustic neuroma. For these patients, gadolinium-enhanced magnetic resonance imaging is the diagnostic gold standard. Auditory brain stem response testing has been used in the past as a screening test for acoustic neuroma, but its apparent sensitivity has fallen as the ability to image smaller acoustic neuromas has improved. Fast spin echo magnetic resonance imaging techniques without gadolinium have been shown to be as effective in the detection of acoustic neuroma as contrast-enhanced magnetic resonance imaging. Limited nonenhanced fast spin echo magnetic resonance imaging now provides an inexpensive alternative for high-resolution imaging of the internal auditory canal and cerebellopontine angle. Fast spin echo magnetic resonance imaging can now be done at a cost approximating auditory brain stem response testing while providing the anatomic information of contrast-enhanced magnetic resonance imaging. Cost analysis was done in the cases of 58 patients with sudden sensorineural hearing loss by comparing the costs for routine workup and screening of acoustic neuroma with the cost of fast spin echo magnetic resonance imaging with the use of screening protocols based on literature review. The potential cost savings of evaluating patients with sudden sensorineural hearing loss with fast spin echo magnetic resonance imaging for acoustic neuroma was substantial, with a 54% reduction in screening costs. In an era of medical economic scrutiny, fast spin echo magnetic resonance imaging has become the most cost-effective method to screen suspected cases of acoustic tumors at our institution by improving existing technology while reducing the cost of providing that technology and eliminating charges for impedance audiometry, auditory brain stem response testing, and contrast-enhanced magnetic resonance imaging.

Application of magnetic resonance neurography in the evaluation of patients with peripheral nerve pathology

1996 ◽  
Vol 85 (2) ◽  
pp. 299-309 ◽  
Author(s):  
Aaron G. Filler ◽  
Michel Kliot ◽  
Franklyn A. Howe ◽  
Cecil E. Hayes ◽  
Dawn E. Saunders ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Time Course ◽  
Spin Echo ◽  
Fast Spin Echo ◽  
Mr Neurography ◽  
Magnetic Resonance Neurography ◽  
Cross Sectional ◽  
Content Type ◽  
Direct Nerve ◽  
Fine Print

✓ Currently, diagnosis and management of disorders involving nerves are generally undertaken without images of the nerves themselves. The authors evaluated whether direct nerve images obtained using the new technique of magnetic resonance (MR) neurography could be used to make clinically important diagnostic distinctions that cannot be readily accomplished using existing methods. The authors obtained T2-weighted fast spin—echo fat-suppressed (chemical shift selection or inversion recovery) and T1-weighted images with planes parallel or transverse to the long axis of nerves using standard or phased-array coils in healthy volunteers and referred patients in 242 sessions. Longitudinal and cross-sectional fascicular images readily distinguished perineural from intraneural masses, thus predicting both resectability and requirement for intraoperative electrophysiological monitoring. Fascicle pattern and longitudinal anatomy firmly identified nerves and thus improved the safety of image-guided procedures. In severe trauma, MR neurography identified nerve discontinuity at the fascicular level preoperatively, thus verifying the need for surgical repair. Direct images readily demonstrated increased diameter in injured nerves and showed the linear extent and time course of image hyperintensity associated with nerve injury. These findings confirm and precisely localize focal nerve compressions, thus avoiding some exploratory surgery and allowing for smaller targeted exposures when surgery is indicated. Direct nerve imaging can demonstrate nerve continuity, distinguish intraneural from perineural masses, and localize nerve compressions prior to surgical exploration. Magnetic resonance neurography can add clinically useful diagnostic information in many situations in which physical examinations, electrodiagnostic tests, and existing image techniques are inconclusive.

Magnetic resonance imaging for vestibular schwannoma: cost-effective protocol for referrals

2019 ◽  
Vol 133 (11) ◽  
pp. 948-952
Author(s):  
B A D Mettias ◽  
M Lyons
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Vestibular Schwannoma ◽  
Selection Criteria ◽  
Spin Echo ◽  
Waiting Times ◽  
Fast Spin Echo ◽  
Resonance Imaging ◽  
Patient Anxiety ◽  
Imaging Protocol

AbstractObjectiveVestibular schwannoma is the most common neoplasm in the cerebellopontine angle, and fast spin-echo T2-weighted magnetic resonance imaging is the most sensitive test for diagnosing it. This study evaluated the financial and time costs of unnecessary magnetic resonance imaging referrals before and after the application of a magnetic resonance imaging protocol.MethodA full audit cycle was used for the assessment. The first cycle in January 2012 was retrospective and evaluated the financial impact of current selection criteria for magnetic resonance imaging referral against standard guidelines. The second cycle in January 2014 was prospective after implementation of the protocol.ResultsThere were 46 and 112 patients who had magnetic resonance imaging during first and second cycle, respectively. Of the referrals for magnetic resonance imaging, 65 per cent versus 81 per cent of the referrals were appropriate in the first and second cycles, respectively. The relative risk was reduced from 0.5 to 0.2. The waiting times for magnetic resonance imaging scans improved.ConclusionSelection criteria for magnetic resonance imaging referral are important in reducing waiting times for scans, patient anxiety and conserving trust resources.

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