ResearchPad - neuroradiology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Venous structures can mimic masses in the foramen magnum]]> https://www.researchpad.co/article/elastic_article_10784 Benign enhancing lesions at the foramen magnum is a recently described entity and believed to represent a varix or ganglion. These lesions are typically described as being single, located posterior to the intradural vertebral artery, and not attached to the dura. These 2 cases demonstrate previously undescribed variations in appearance of these lesions including contacting the posterior inferior cerebellar artery and lateral epidural plexus/dura, segmental dilatations, transverse and linear configuration, and visualization on an unenhanced CT head. These lesions most likely reflect bridging veins and are structures that clinicians should be aware of to avoid unnecessary follow-up or surgical intervention.

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<![CDATA[Scan–rescan and inter-vendor reproducibility of neurite orientation dispersion and density imaging metrics]]> https://www.researchpad.co/article/Na5962a46-a888-4a19-9965-c084b7b5f450

Purpose

The reproducibility of neurite orientation dispersion and density imaging (NODDI) metrics in the human brain has not been explored across different magnetic resonance (MR) scanners from different vendors. This study aimed to evaluate the scan–rescan and inter-vendor reproducibility of NODDI metrics in white and gray matter of healthy subjects using two 3-T MR scanners from two vendors.

Methods

Ten healthy subjects (7 males; mean age 30 ± 7 years, range 23–37 years) were included in the study. Whole-brain diffusion-weighted imaging was performed with b-values of 1000 and 2000 s/mm2 using two 3-T MR scanners from two different vendors. Automatic extraction of the region of interest was performed to obtain NODDI metrics for whole and localized areas of white and gray matter. The coefficient of variation (CoV) and intraclass correlation coefficient (ICC) were calculated to assess the scan–rescan and inter-vendor reproducibilities of NODDI metrics.

Results

The scan–rescan and inter-vendor reproducibility of NODDI metrics (intracellular volume fraction and orientation dispersion index) were comparable with those of diffusion tensor imaging (DTI) metrics. However, the inter-vendor reproducibilities of NODDI (CoV = 2.3–14%) were lower than the scan–rescan reproducibility (CoV: scanner A = 0.8–3.8%; scanner B = 0.8–2.6%). Compared with the finding of DTI metrics, the reproducibility of NODDI metrics was lower in white matter and higher in gray matter.

Conclusion

The lower inter-vendor reproducibility of NODDI in some brain regions indicates that data acquired from different MRI scanners should be carefully interpreted.

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<![CDATA[Radio-pathological review of a metastatic renal cell carcinoma within a meningioma: A case report of collision tumor]]> https://www.researchpad.co/article/N7c6b8705-b6a5-4daa-bbcb-7dcbc43af785

We report a case of a collision tumor, a meningioma complicated with metastasis from a primary renal cell carcinoma. A 75-year-old man, with known history of renal cell carcinoma, and 10-year history of stable meningioma developed neurological symptoms. Computed tomography and magnetic resonance imaging revealed left frontal intracranial extra-axial mass with imaging criteria suspicious for an atypical meningioma or hemangiopericytoma. Given the history of a known primary, the possibility of brain metastasis was included. Pathology confirmed the presence of metastatic renal cell carcinoma nidus with a surrounding meningioma. Tumor-to-tumor metastasis or collision tumor is a very rare phenomenon. Atypical radiologic findings with positive history of a primary extracranial tumor should raise the suspicion of potential metastases.

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<![CDATA[Encephalocraniocutaneous lipomatosis: A rare congenital neurocutaneous syndrome]]> https://www.researchpad.co/article/Nd5b9e6a7-fd74-45b3-8ced-9d1356953a17

Encephalocraniocutaneous lipomatosis (ECCL) is a rare sporadic congenital neurocutaneous disorder with quite specific clinical features and neuroimaging pattern that is well seen on MR imaging.

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<![CDATA[Osteoblastoma in the occipital bone: A case report of a rare tumor in the calvarium]]> https://www.researchpad.co/article/Nc1c317db-19b4-4d68-a4e7-40af8751a8a4

Osteoblastomas infrequently occur in the calvarium, displaying a preference for temporal and frontal bones when it does. We present an unusual case of a large, expansile osteoblastoma in the occipital bone of a 23-year-old man who presented with a nontender lump at the back of his head. Initial computed tomography scan showed a large occipital bone mass, and after additional imaging, a gross total resection was performed. Histopathological examination revealed an osteoblastoma. Although these tumors are benign, overlapping imaging characteristics of lesions affecting the calvarium often present a diagnostic dilemma. This case emphasizes the importance of imaging in the management and work-up of these patients to decrease the risk of complications and assists surgeons in their preoperative planning.

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<![CDATA[Autosomal recessive spastic ataxia of charlevoix-saguenay: Findings from MRI in two adult Italian siblings]]> https://www.researchpad.co/article/Ne6d32bce-e7f5-4cb7-98bb-a9c5b41b6d65

Autosomal recessive spastic ataxia of Charlevoix-Saguenay is a rare neurodegenerative disorder caused by homozygous mutations in SACSgene. We present finding on MR imaging in 2 adult Italian siblings. According to the literature we have described same of typical MRI finding of autosomal recessive spastic ataxia of Charlevoix-Saguenay disease. We found slight differences in neuroimaging pattern in our patients with a similar genotype but different age and clinical severity, this suggest that brain MRI may provide potential biomarkers to assess disease progression.

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<![CDATA[The “Cone-Head” sign: Magnetic resonance image findings of the “Headspin Hole”, an overuse injury found in breakdancers]]> https://www.researchpad.co/article/Ne990d58b-f295-4d89-a78f-2e7cdfc4a365

Breakdancing can cause the formation of a painless lump on the scalp at the vertex of the skull, with associated hair loss called a “Headspin Hole.” This occurs secondary to chronic inflammation from performing spinning dance moves on the head. We present the radiological findings of the “Headspin Hole” in a 38-year-old male with a history of breakdancing. Magnetic resonance imaging revealed a cone-shaped deformity on the vertex of the skull with deep scalp thickening adjacent to the outer-table cortex. Currently in the literature, there is no description of the radiological findings of this cone-shaped deformity on the vertex of the skull, we refer to this as the “Cone-Head Sign.”

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<![CDATA[Redundant nerve roots in lumbar spinal stenosis: inter- and intra-rater reliability of an MRI-based classification]]> https://www.researchpad.co/article/N557f23af-40b9-4266-a29d-e17230c55595

Purpose

Patients with central lumbar spinal stenosis (LSS) have a longer symptom history, more severe stenosis, and worse postoperative outcomes, when redundant nerve roots (RNRs) are evident in the preoperative MRI. The objective was to test the inter- and intra-rater reliability of an MRI-based classification for RNR.

Methods

This is a retrospective reliability study. A neuroradiologist, an orthopedic surgeon, a neurosurgeon, and three orthopedic surgeons in-training classified RNR on 126 preoperative MRIs of patients with LSS admitted for microsurgical decompression. On sagittal and axial T2-weighted images, the following four categories were classified: allocation (A) of the key stenotic level, shape (S), extension (E), and direction (D) of the RNR. A second read with cases ordered differently was performed 4 weeks later. Fleiss and Cohen’s kappa procedures were used to determine reliability.

Results

The allocation, shape, extension, and direction (ASED) classification showed moderate to almost perfect inter-rater reliability, with kappa values (95% CI) of 0.86 (0.83, 0.90), 0.62 (0.57, 0.66), 0.56 (0.51, 0.60), and 0.66 (0.63, 0.70) for allocation, shape, extension, and direction, respectively. Intra-rater reliability was almost perfect, with kappa values of 0.90 (0.88, 0.92), 0.86 (0.84, 0.88), and 0.84 (0.81, 0.87) for shape, extension, and direction, respectively. Intra-rater kappa values were similar for junior and senior raters. Kappa values for inter-rater reliability were similar between the first and second reads (p = 0.06) among junior raters and improved among senior raters (p = 0.008).

Conclusions

The MRI-based classification of RNR showed moderate-to-almost perfect inter-rater and almost perfect intra-rater reliability.

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<![CDATA[Unilateral cerebral herniation resulting in combined contralateral superior cerebellar artery territory infarction and mesencephalic injury: Two cases of a severe unrecognized variant of Kernohan notch phenomenon?]]> https://www.researchpad.co/article/N5447ebf8-d691-4dc4-bb41-4e1dd03ada34

A case of unilateral cerebral herniation due to an acute middle cerebral artery territory infarct and a second case of unilateral cerebral herniation due to an acute subdural hematoma are presented in this article. In both instances, the unilateral cerebral herniation resulted in a combined contralateral superior cerebellar artery territory infarction and mesencephalic injury. Unilateral cerebral herniation resulting in a combined contralateral superior cerebellar artery territory infarct and mesencephalic injury is previously undescribed in the literature and likely reflects a severe unrecognized variant of Kernohan notch phenomenon.

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<![CDATA[Metastatic meningioma: Case report of a WHO grade I meningioma with liver metastases and review of the literature]]> https://www.researchpad.co/article/Nd73c6953-aeca-44ad-b52c-926e730c167f

Meningioma represents the most frequently diagnosed primary brain tumor, accounting for over one-third of central nervous system neoplasms. The majority of tumors are categorized as benign. However, albeit rarely, meningiomas may metastasize to distant sites. We describe a 78-year-old man with a history of recurrent World Health Organization grade I meningioma managed who presented for evaluation of weakness and urinary retention. A computed tomography scan obtained in the emergency department revealed multiple scattered low-density liver lesions. Subsequent magnetic resonance imaging showed a 5.5-centimeter heterogeneous enhancing mass with 2 smaller enhancing lesions suspicious for a primary or secondary malignant neoplasm. Microscopic examination of a tissue sample obtained via liver biopsy demonstrated a metastatic spindle cell neoplasm with histologic features compatible with a diagnosis of World Health Organization grade I transitional meningioma. The patient was referred to hematology/oncology for systemic therapy.

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<![CDATA[Reliability of dynamic contrast-enhanced magnetic resonance imaging data in primary brain tumours: a comparison of Tofts and shutter speed models]]> https://www.researchpad.co/article/N927965fc-6cfc-4f8f-bb2d-f1cfcf4f97e4

Purpose

The purpose of this study is to investigate the robustness of pharmacokinetic modelling of DCE-MRI brain tumour data and to ascertain reliable perfusion parameters through a model selection process and a stability test.

Methods

DCE-MRI data of 14 patients with primary brain tumours were analysed using the Tofts model (TM), the extended Tofts model (ETM), the shutter speed model (SSM) and the extended shutter speed model (ESSM). A no-effect model (NEM) was implemented to assess overfitting of data by the other models. For each lesion, the Akaike Information Criteria (AIC) was used to build a 3D model selection map. The variability of each pharmacokinetic parameter extracted from this map was assessed with a noise propagation procedure, resulting in voxel-wise distributions of the coefficient of variation (CV).

Results

The model selection map over all patients showed NEM had the best fit in 35.5% of voxels, followed by ETM (32%), TM (28.2%), SSM (4.3%) and ESSM (< 0.1%). In analysing the reliability of Ktrans, when considering regions with a CV < 20%, ≈ 25% of voxels were found to be stable across all patients. The remaining 75% of voxels were considered unreliable.

Conclusions

The majority of studies quantifying DCE-MRI data in brain tumours only consider a single model and whole tumour statistics for the output parameters. Appropriate model selection, considering tissue biology and its effects on blood brain barrier permeability and exchange conditions, together with an analysis on the reliability and stability of the calculated parameters, is critical in processing robust brain tumour DCE-MRI data.

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<![CDATA[Convolutional neural network-based segmentation can help in assessing the substantia nigra in neuromelanin MRI]]> https://www.researchpad.co/article/N249107df-c102-4415-83d4-51e52367b478

Purpose

This study aimed to evaluate the accuracy and diagnostic test performance of the U-net-based segmentation method in neuromelanin magnetic resonance imaging (NM-MRI) compared to the established manual segmentation method for Parkinson’s disease (PD) diagnosis.

Methods

NM-MRI datasets from two different 3T-scanners were used: a “principal dataset” with 122 participants and an “external validation dataset” with 24 participants, including 62 and 12 PD patients, respectively. Two radiologists performed SNpc manual segmentation. Inter-reader precision was determined using Dice coefficients. The U-net was trained with manual segmentation as ground truth and Dice coefficients used to measure accuracy. Training and validation steps were performed on the principal dataset using a 4-fold cross-validation method. We tested the U-net on the external validation dataset. SNpc hyperintense areas were estimated from U-net and manual segmentation masks, replicating a previously validated thresholding method, and their diagnostic test performances for PD determined.

Results

For SNpc segmentation, U-net accuracy was comparable to inter-reader precision in the principal dataset (Dice coefficient: U-net, 0.83 ± 0.04; inter-reader, 0.83 ± 0.04), but lower in external validation dataset (Dice coefficient: U-net, 079 ± 0.04; inter-reader, 0.85 ± 0.03). Diagnostic test performances for PD were comparable between U-net and manual segmentation methods in both principal (area under the receiver operating characteristic curve: U-net, 0.950; manual, 0.948) and external (U-net, 0.944; manual, 0.931) datasets.

Conclusion

U-net segmentation provided relatively high accuracy in the evaluation of the SNpc in NM-MRI and yielded diagnostic performance comparable to that of the established manual method.

Electronic supplementary material

The online version of this article (10.1007/s00234-019-02279-w) contains supplementary material, which is available to authorized users.

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<![CDATA[Standardized image evaluation in patients with idiopathic normal pressure hydrocephalus: consistency and reproducibility]]> https://www.researchpad.co/article/N37c5676d-f6f1-42f7-a08a-0a986675ca86

Purpose

Assess the agreement for two investigators between computed tomography (CT) and magnetic resonance imaging (MRI) for seven imaging features included in the iNPH Radscale, a radiological screening tool.

Methods

The study included 35 patients with idiopathic normal pressure hydrocephalus (iNPH) who were treated surgically from 2011 to 2015 at Uppsala University Hospital with preoperative CT and MRI performed with maximum 3 months between scans. Seven features were assessed: Evans’ index, temporal horn size, callosal angle, periventricular white matter changes, narrow high convexity sulci, focally enlarged sulci, and enlarged Sylvian fissures. All scans were assessed by two investigators who were blinded to each other’s results and to clinical data.

Results

The agreement between CT and MRI was almost perfect for Evans’ index, temporal horns, narrow sulci, and Sylvian fissures (kappa and intraclass correlation, 0.84–0.91, p ≤ 0.001). There was substantial to almost perfect agreement for callosal angle and focally enlarged sulci. The concordance between modalities was fair for changes in periventricular white matter.

Conclusion

CT and MRI are equally good for assessing radiological signs associated with iNPH except for periventricular white matter changes, as MRI has superior soft tissue contrast. The other imaging features can be evaluated consistently, and assessments are reproducible independent of modality. Therefore, the iNPH Radscale is applicable to both CT and MRI and may become an important tool for standardized evaluation in the workup in patients with suspected iNPH.

Electronic supplementary material

The online version of this article (10.1007/s00234-019-02273-2) contains supplementary material, which is available to authorized users.

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<![CDATA[Diagnostic accuracy of flat-panel computed tomography in assessing cerebral perfusion in comparison with perfusion computed tomography and perfusion magnetic resonance: a systematic review]]> https://www.researchpad.co/article/N5e9e3454-fe4f-4292-ad87-1d04311929b8

Purpose

Flat-panel computed tomography (FP-CT) is increasingly available in angiographic rooms and hybrid OR’s. Considering its easy access, cerebral imaging using FP-CT is an appealing modality for intra-procedural applications. The purpose of this systematic review is to assess the diagnostic accuracy of FP-CT compared with perfusion computed tomography (CTP) and perfusion magnetic resonance (MRP) in cerebral perfusion imaging.

Methods

We performed a systematic literature search in the Cochrane Library, MEDLINE, Embase, and Web of Science up to June 2019 for studies directly comparing FP-CT with either CTP or MRP in vivo. Methodological quality was assessed using the QUADAS-2 tool. Data on diagnostic accuracy was extracted and pooled if possible.

Results

We found 11 studies comparing FP-CT with CTP and 5 studies comparing FP-CT with MRP. Most articles were pilot or feasibility studies, focusing on scanning and contrast protocols. All patients studied showed signs of cerebrovascular disease. Half of the studies were animal trials. Quality assessment showed unclear to high risks of bias and low concerns regarding applicability. Five studies reported on diagnostic accuracy; FP-CT shows good sensitivity (range 0.84–1.00) and moderate specificity (range 0.63–0.88) in detecting cerebral blood volume (CBV) lesions.

Conclusions

Even though FP-CT provides similar CBV values and reconstructed blood volume maps as CTP in cerebrovascular disease, additional studies are required in order to reliably compare its diagnostic accuracy with cerebral perfusion imaging.

Electronic supplementary material

The online version of this article (10.1007/s00234-019-02285-y) contains supplementary material, which is available to authorized users.

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<![CDATA[Glioblastoma with brainstem leptomeningeal pseudoprogression following radiation therapy]]> https://www.researchpad.co/article/5ca25d5bd5eed0c4846d5166

In brain tumor patients, worsening of imaging findings in the first 6 months after surgical debulking and chemoradiation can occur in the absence of tumor growth, a phenomenon known as pseudoprogression. Awareness of pseudoprogression is important as it can lead to unnecessary additional changes in patient management. In this case, a patient with bilateral frontal glioblastoma presented with new post-treatment brainstem leptomeningeal enhancement which was distant from the original tumor site, concerning for disease progression. However, the patient was asymptomatic and correlation of leptomeningeal enhancement locations with radiation therapy dose maps revealed high doses at the affected site, supporting a diagnosis of treatment effect which was confirmed by resolution on follow-up imaging after treatment with steroids. Parenchymal pseudoprogression in brain tumor patients is well-documented, but worsening leptomeningeal enhancement following therapy may also represent treatment effects. If spatially remote leptomeningeal enhancement occurs, correlation with radiation dose maps may be useful in suggesting a diagnosis of treatment effect over tumor progression.

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<![CDATA[Posterior reversible encephalopathy syndrome with isolated infratentorial involvement: A case report]]> https://www.researchpad.co/article/5c9bc3f3d5eed0c484ee637b

Posterior reversible encephalopathy syndrome (PRES) is a clinical and radiological entity of acute neurological symptoms associated with characteristic MRI finding. Vasogenic edema in the white matter of parieto-occipital regions is the classical MRI findings. Spinal cord involvement in PRES is extremely rare and frequently underrecognized condition. Recently, a variant-type PRES with isolated involvement of infratentorial structures is getting more attention. Herein, we present a case of hypertensive emergency and associated radiological features of PRES with isolated involvement of the brain stem, cerebellum, and spinal cord.

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<![CDATA[Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia: A case report]]> https://www.researchpad.co/article/5c929805d5eed0c48437e9be

Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare neurodegenerative disorder characterized by cerebral white matter abnormalities, myelin loss, and axonal swellings. ALSP is caused by mutations in colony stimulating factor 1 receptor gene. We report an ASLP patient with asymptomatic intracranial calcifications distributed in white matter found incidentally in a health screening.

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<![CDATA[Role of 3D SPACE sequence and susceptibility weighted imaging in the evaluation of hydrocephalus and treatment-oriented refined classification of hydrocephalus]]> https://www.researchpad.co/article/5c4b90b0d5eed0c48487400f

Objective:

The aim of our study was to evaluate the diagnostic utility of three-dimensional sampling perfection with application optimized contrast using different flip angle evolution (3D SPACE) sequence and Susceptibility Weighted Imaging (SWI) in hydrocephalus and to propose a refined definition and classification of hydrocephalus with relevance to the selection of treatment option.

Materials and Methods:

A prospective study of 109 patients with hydrocephalus was performed with magnetic resonance imaging (MRI) brain using standardized institutional sequences along with additional sequences 3D SPACE and SWI. The images were independently read by two senior neuroradiologists and the etiopathogenesis of hydrocephalus was arrived by consensus.

Results:

With conventional sequences, 46 out of 109 patients of hydrocephalus were diagnosed as obstructive of which 21 patients showed direct signs of obstruction and 25 showed indirect signs. In the remaining 63 patients of communicating hydrocephalus, cause could not be found out in 41 patients. Whereas with 3D SPACE sequence, 88 patients were diagnosed as obstructive hydrocephalus in which all of them showed direct signs of obstruction and 21 patients were diagnosed as communicating hydrocephalus. By including SWI, we found out hemorrhage causing intraventricular obstruction in three patients and hemorrhage at various sites in 24 other patients. With these findings, we have classified the hydrocephalus into communicating and noncommunicating, with latter divided into intraventricular and extraventricular obstruction, which is very well pertaining to the selection of surgical option.

Conclusion:

We strongly suggest to include 3D SPACE and SWI sequences in the set of routine MRI sequences, as they are powerful diagnostic tools and offer complementary information regarding the precise evaluation of the etiopathogenesis of hydrocephalus and have an effective impact in selecting the mode of management.

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<![CDATA[Olfactory fossa depth: CT analysis of 1200 patients]]> https://www.researchpad.co/article/5c4b9094d5eed0c484873bd8

Background:

Olfactory fossa (OF) is a depression in anterior cranial cavity whose floor is formed by cribriform plate of ethmoid. Lateral lamella, which forms its lateral boundary, is a thin plate of bone and is at risk of injury during functional endoscopic sinus surgery, especially when fossa is deep/asymmetric.

Aims:

To measure the variations in the depth of OF and categorize Kerala population as per Keros classification using computed tomography (CT).

Settings and Design:

This study was conducted in our institution from January 2016 to August 2017. Patients >16 years of age undergoing CT scan of paranasal sinuses (PNS) were included.

Materials and Methods:

Coronal PNS CT scan studies of 1200 patients were reviewed. The depth of OF was measured from vertical height of lateral lamella.

Statistical Methods:

Results were analyzed according to gender and laterality using independent sample t-test and Chi-square test.

Results:

The mean depth of OF was 5.26 ± 1.69 mm. Statistically significant difference was seen in the mean depth of OF between males and females but not between right and left sides. Keros type I was found on 420 sides (17.5%), type II in 1790 (74.6%), and type III on 190 sides (7.9%). Type III Keros was more on the right (9%) than left (6.8%) side, more in males (9.5%) than females (5.9%), and more among males on the right side (11.4%). Asymmetry in OF depth between two sides was seen in 75% of subjects.

Conclusion:

Prevalence of the dangerous type III OF, even though low, is significant especially among males and on the right side. Therefore, preoperative assessment of OF depth must be done to reduce iatrogenic complications.

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<![CDATA[Precontrast T1 signal measurements of normal pituitary and microadenoma: A retrospective analysis through DCE MRI signal time curves]]> https://www.researchpad.co/article/5c4b9098d5eed0c484873c81

Background:

The dynamic contrast enhanced magnetic resonance imaging (DCE MRI) has currently become the most utilized technique for the detection of pituitary microadenoma. However, owing to differential enhancement of normal pituitary, high rate of false positivity remains a concern in its interpretation.

Purpose:

Our aim was to assess the utility of precontrast T1 signal intensity ratio (SIR) of the lesions suspected on DCE MRI, in prediction of presence of microadenoma.

Materials and Methods:

We retrospectively reviewed MRI of 23 patients referred for DCE MRI of pituitary (group 1, 15 patients with diagnosis of pituitary microadenoma; and group 2, patients not clinically labeled as microadenoma). STC were plotted and T1-SIR at t = 0 s was obtained at the suspicious zone of differential enhancement (SIR T) and normal pituitary (SIR P). SIR difference (SIR P − SIR T) and relative SIR difference (SIR P − SIR T/SIR P) were calculated for each patient and was compared between the two groups.

Results:

Mean T1 SIR is lower in patients with microadenoma than those without (P = 0.065). SIR difference and relative SIR difference was higher in patients with microadenoma (P = 0.003 and 0.005, respectively). Receiver-operated characteristic curve analysis demonstrated that a cut-off of 26 and 0.107 for SIR difference and relative SIR difference, respectively, could diagnose microadenoma with 100% specificity and reasonable sensitivities.

Conclusion:

The baseline precontrast T1 SIR evaluation of the lesion suspected to be microadenoma on DCE MRI, derived through STC curve, can increase diagnostic confidence in diagnosis of microadenoma.

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