Extra-mammary findings in breast MRI

Objectives  

Incidental extra-mammary findings in breast Magnetic Resonance Imaging (MRI) may be benign in nature, but may also represent a metastasis or another important lesion. We aimed to analyse the prevalence and clinical relevance of these unexpected findings.     

Value of MRI and diffusion-weighted MRI for the diagnosis of locally recurrent rectal cancer

Objectives  

To evaluate the accuracy of standard MRI, diffusion-weighted MRI (DWI) and fusion images for the diagnosis of locally recurrent rectal cancer in patients with a clinical suspicion of recurrence.     

Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)

Objective  

To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa).     

Diagnosis of liver metastases: value of diffusion-weighted MRI compared with gadolinium-enhanced MRI

Objective  

The full diagnostic value of diffusion-weighted (DW) MRI in the evaluation of liver metastases remains uncertain. The aim of the present study was to assess the diagnostic accuracy of DW-MRI and contrast-enhanced MRI (CE-MRI) using extracellular gadolinium chelates, with the reference standard established by consensus interpretation of confirmatory imaging and histopathologic data.     

Ischiofemoral impingement: evaluation with new MRI parameters and assessment of their reliability

Objective  

The aim of this study was to describe the magnetic resonance imaging (MRI) findings in patients with ischiofemoral impingement (IFI) and to evaluate the reliability of these MRI findings.     

Skeletal muscle evaluation by MRI in a rabbit model of acute ischaemia

Objective:

To assess rhabdomyolysis-associated skeletal muscle changes induced by complete ischaemia in rabbits using MRI.

Methods:

Acute ischaemia was induced in the right hind limb of 34 New Zealand white rabbits by arterial ligation. MRI of vastus lateralis was carried out pre-operatively and every hour post-operatively up to 7 h. T₁ weighted images, T₂ weighted images with fat suppression, T₂ maps and diffusion tensor scans were obtained. The correlation of MRI findings with histopathological changes in biopsies of vastus lateralis was examined.

Results:

Histopathology demonstrated early cellular oedema 1 h post ischaemia and irreversible injuries by 7 h, including loss of striation and broken muscle fibres. T₂ weighted images with fat suppression showed inhomogeneous high signal intensity of vastus lateralis, which progressively increased from 2 h following ischaemia. The T₂ relaxation rate of ischaemic vastus lateralis was significantly greater than normal muscle (p<0.001) and demonstrated a linear increase with time following ischaemia. A similar linear increase was also found in the ischaemic vastus lateralis apparent diffusion coefficient (ADC) 1–5 h post ischaemia (p=0.006). Both the T₂ ADC and fractional anisotropy (FA) were significantly higher on the ischaemic side 7 h post ischaemia (for T₂, p=0.02; for ADC, p=0.004).

Conclusion:

Muscle oedema is detectable on MR images and is reflected well by T₂, ADC and FA values. MRI may have value in clinical evaluation of rhabdomyolysis.

Advances in knowledge:

Ischaemic changes detected by MRI may have value in the diagnosis of rhabdomyolysis.Rhabdomyolysis is a syndrome of skeletal muscle breakdown characterised by myonecrosis and subsequent leakage of intracellular contents into the circulation. The most common causes include muscle injury, excessive exercise, drug and alcohol abuse, muscle ischaemia, heat stroke, toxins and infections [1]. Definitive diagnosis of rhabdomyolysis is predominately based on laboratory findings, which include an elevated level of serum creatine kinase (CK) and myoglobin as well as the presence of urinary myoglobin. Immediate and aggressive interventions are critical in clinical management of rhabdomyolysis; by preventing complications, such as hyperkalaemia and acute renal failure, the prognosis can be significantly improved [2].Clinical manifestations of rhabdomyolysis vary extensively from asymptomatic to life threatening. Also, the aetiology remains elusive particularly in the early phase, posing a challenge to identify the underlying causes. Although elevation of the serum CK level is the most sensitive indicator of muscle injury, levels peak rather early and decrease rapidly after injury. When a patient is not admitted immediately, recognition and evaluation of rhabdomyolysis may become difficult. Reports suggest that over one-quarter of patients with rhabdomyolysis are not clinically diagnosed [3,4].MRI plays an important role in the detection of skeletal muscle lesions that change muscle size, shape or signal intensity [5,6]. Review of medical records has shown that MR images can be used to effectively localise muscle lesions in rhabdomyolysis and assess extent [4,7–12]. MRI has been shown to be more sensitive for detection of rhabdomyolysis skeletal muscle lesions than ultrasonography and CT [8]. It has also been reported that MR findings in rhabdomyolysis patients correlate well with clinical symptoms and can help distinguish aetiologies [9]. Nevertheless, prospective studies of MRI for rhabdomyolysis and histopathological correlation of imaging findings remain scarce.In this study, we describe MRI of skeletal muscle changes in a modified rabbit hind limb model of complete ischaemia and correlate findings with histopathological features of the affected muscle.     

Whole-body MRI using a sliding table and repositioning surface coil approach

Objective  

To introduce and assess a new way of performing whole-body magnetic resonance imaging (MRI) using a non-integrated surface coil approach as available on most clinical MRI systems worldwide.     

Prospective comparison of T2w-MRI and dynamic-contrast-enhanced MRI, 3D-MR spectroscopic imaging or diffusion-weighted MRI in repeat TRUS-guided biopsies

Objectives  

To compare T2-weighted MRI and functional MRI techniques in guiding repeat prostate biopsies.     

Muscle MRI findings in facioscapulohumeral muscular dystrophy

Objectives

Facioscapulohumeral muscular dystrophy (FSHD) is characterized by extremely variable degrees of facial, scapular and lower limb muscle involvement. Clinical and genetic determination can be difficult, as molecular analysis is not always definitive, and other similar muscle disorders may have overlapping clinical manifestations.

Methods and Materials

Whole-body muscle MRI examination for fat infiltration, atrophy and oedema was performed to identify specific patterns of muscle involvement in FSHD patients (30 subjects), and compared to a group of control patients (23) affected by other myopathies (NFSHD).

Results

In FSHD patients, we detected a specific pattern of muscle fatty replacement and atrophy, particularly in upper girdle muscles. The most frequently affected muscles, including paucisymptomatic and severely affected FSHD patients, were trapezius, teres major and serratus anterior. Moreover, asymmetric muscle involvement was significantly higher in FSHD as compared to NFSHD patients.

Conclusions

In conclusion, muscle MRI is very sensitive for identifying a specific pattern of involvement in FSHD patients and in detecting selective muscle involvement of non-clinically testable muscles. Muscle MRI constitutes a reliable tool for differentiating FSHD from other muscular dystrophies to direct diagnostic molecular analysis, as well as to investigate FSHD natural history and follow-up of the disease.

Key Points

? Muscle MRI identifies a specific pattern of muscle involvement in FSHD patients. ? Muscle MRI may predict FSHD in asymptomatic and severely affected patients. ? Muscle MRI of upper girdle better predicts FSHD. ? Muscle MRI may differentiate FSHD from other forms of muscular dystrophy. ? Muscle MRI may show the involvement of non-clinical testable muscles.

     

MR-guided discography using an open 1 Tesla MRI system

Objective  

To evaluate the feasibility of MR-guided discography using an open 1 Tesla MRI system.     

Visual MRI Grading System to Evaluate Atrophy of the Supraspinatus Muscle

Objective

To investigate the interobserver reproducibility and diagnostic feasibility of a visual grading system for assessing atrophy of the supraspinatus muscle on magnetic resonance imaging (MRI).

Materials and Methods

Three independent radiologists retrospectively evaluated the occupying ratio of the supraspinatus muscle in the supraspinatus fossa on 192 shoulder MRI examinations in 188 patients using a 3-point visual grading system (1, ≥ 60%; 2, 30-59%; 3, < 30%) on oblique sagittal T1-weighted images. The inter-reader agreement and the agreement with the reference standard (3-point grades according to absolute occupying ratio values quantitatively measured by directly contouring the muscles on MRI) were analyzed using weighted kappa. The visual grading was applied by a single reader to a group of 100 consecutive patients who had undergone rotator cuff repair to retrospectively determine the association between the visual grades at preoperative state and postsurgical occurrences of retear.

Results

The inter-reader weighted kappa value for the visual grading was 0.74 when averaged across three reader pairs (0.70-0.77 for individual reader pairs). The weighted kappa value between the visual grading and the reference standard ranged from 0.75 to 0.83. There was a significant difference in retear rates of the rotator cuff between the 3 visual grades of supraspinatus muscle atrophy on MRI in univariable analysis (p < 0.001), but not in multivariable analysis (p = 0.026).

Conclusion

The 3-point visual grading system may be a feasible method to assess the severity of supraspinatus muscle atrophy on MRI and assist in the clinical management of patients with rotator cuff tear.     

An iterative two-threshold analysis for single-subject functional MRI of the human brain

Objectives  

Current thresholding strategies for the analysis of functional MRI (fMRI) datasets may suffer from specific limitations (e.g. with respect to the required smoothness) or lead to reduced performance for a low signal-to-noise ratio (SNR). Although a previously proposed two-threshold (TT) method offers a promising solution to these problems, the use of preset settings limits its performance. This work presents an optimised TT approach that estimates the required parameters in an iterative manner.     

Juxtafacet cysts of the lumbar spine: a positional MRI study

Background/Aims  

Juxtafacet cysts (JFC) are related to facet joint degeneration. Supine MRI is routinely used to evaluate JFC. However, some JFC are missed and found only intraoperatively. The present study addresses positional MRI features and factors leading to variation in the size of JFC.     

Integrative role of MRI in the evaluation of primary biliary cirrhosis

Objectives  

To evaluate magnetic resonance imaging (MRI) findings in patients with primary biliary cirrhosis (PBC) and to determine the value of diffusion-weighted imaging (DWI) in the assessment of liver fibrosis.     

Ischiofemoral impingement syndrome: Spectrum of MRI findings in comparison to normal subjects

Objective

To evaluate the MRI findings of patients with ischiofemoral impingement in comparison to healthy subjects.

Materials and methods

The study included 34 subjects; 14 patients clinically suspected to have ischiofemoral impingement and twenty volunteer subjects used as a control group. The MRI images were evaluated for both hip joints for two measurable parameters; the ischiofemoral space (IFS) and the quadratus femoris space (QFS). The quadratus femoris muscles were evaluated for; muscle edema, tear, or muscle atrophy. Statistical analysis was performed with the (Minitab Ver.16). The Paired t-test and ANOVA test were used to analyze differences of the distance measurements in each side of the patient group as well as both sides in the control group. Receiver operating characteristic (ROC) curves were used to determine optimal threshold values of IFS and QFS using (MedCalc software, version 12.7.8.0.).

Results

There were statistical differences between affected hip and healthy hip regarding IFS and QFS (P = 0.000) associated with QF muscle changes ranged from focal edema to partial tear in the affected joints.

Conclusion

Ischiofemoral impingement is an uncommon cause of hip pain. Our study illustrates the MR spectrum of IFS, QFS and quadratus femoris muscle abnormalities.     

Design and performance from an integrated PET/MRI system for small animals

Objective  

Although simultaneous measurements of PET and magnetic resonance imaging (MRI) can provide interesting results in molecular imaging research, most of the combined systems are huge and animal handling in the system is not easy. To minimize these problems, we developed a compact integrated PET/MRI (iPET/MRI) system for small animals.     

MRI findings,patterns of disease distribution,and muscle fat fraction calculation in five patients with Charcot-Marie-Tooth type 2 F disease

Purpose  

To describe the magnetic resonance imaging (MRI) pattern of muscle involvement and disease progression in five patients with late-onset Charcot-Marie-Tooth (CMT) disease type 2 F, due to a previously unknown mutation.     

MRI differentiates femoral condylar ossification evolution from osteochondritis dissecans. A new sign

Objective  

To determine if MRI (magnetic resonance imaging) of the femoral condyles in children can differentiate variations in ossification from osteochondritis dissecans (OCD).     

The added value of contrast-enhanced ultrasound in patients with colorectal cancer undergoing preoperative evaluation with extensive gadobenate dimeglumine liver MRI

Objectives  

To evaluate the added value of pre- and intraoperative contrast-enhanced ultrasound (transabdominal, or TCEUS and intraoperative, or ICEUS, respectively) in patients with known or highly suspected colorectal cancer liver metastases (CRLM) who have previously undergone extensive gadobenate dimeglumine (Gd-BOPTA) liver MRI.     

Diffusion-weighted MRI of denervated muscle: a clinical and experimental study

Objective  The aim of this study was to investigate skeletal muscle denervation using diffusion-weighted magnetic resonance imaging (DWMRI). Materials and methods  Sciatic nerve axotomy was performed in a group of nine New Zealand White rabbits, and electromyographic (EMG), pathological, and DWMRI studies were conducted on ipsilateral hamstring muscles 1 and 8 days after axotomy. In addition, DWMRI studies were carried out on leg muscles of ten patients with acute and subacute lumbosacral radiculopathy. Results  High intensity signals on short tau inversion recovery (STIR) magnetic resonance imaging and an increased apparent diffusion coefficient (ADC) were observed in denervated muscles of the animals 1 and 8 days after axotomy as well as in denervated muscles of the patients with radiculopathy. In the clinical study, ADC was 1.26 ± 0.18 × 10⁻⁹ m²/s in normal muscle and increased to 1.56 ± 0.23 × 10⁻⁹ m²/s in denervated muscles (p = 0.0016). In animals, EMG and muscle pathological studies were normal 1 day after axotomy, and the muscles demonstrated spontaneous activity on EMG and neurogenic atrophy on histological studies 7 days later. Conclusion  This DWMRI study demonstrates that enlargement of extracellular fluid space in muscle denervation is an early phenomenon occurring several days before the appearance of EMG and histological abnormalities. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Nathalie Holl and Andoni Echaniz-Laguna contributed equally to this work.