Late clinical and radiological complications of stereotactical radiosurgery of arteriovenous malformations of the brain

Introduction

Post-radiation injury of patients with brain arteriovenous malformations (AVM) include blood–brain barrier breakdown (BBBB), edema, and necrosis. Prevalence, clinical relevance, and response to treatment are poorly known. We present a series of consecutive brain AVM treated with stereotactic radiosurgery describing the appearance of radiation injury and clinical complications.

Methods

Consecutive patients with annual clinical and radiological follow-up (median length 63 months). Edema and BBBB were classified in four groups (minimal, perilesional, moderate, or severe), and noted together with necrosis. Clinical symptoms of interest were intracranial hypertension, new neurological deficits, new seizures, and brain hemorrhages.

Results

One hundred two cases, median age 34 years, 52 % male. Median irradiated volume 3.8 cc, dose to the margin of the nidus 18.5 Gy. Nineteen patients underwent a second radiosurgery. Only 42.2 % patients remained free from radiation injury. Edema was found in 43.1 %, blood–brain barrier breakdown in 20.6 %, necrosis in 6.9 %. Major injury (moderate or severe edema, moderate or severe BBBB, or necrosis) was found in 20 of 102 patients (19.6 %). AVM diameter >3 cm and second radiosurgery were independent predictors. Time to the worst imaging was 60 months. Patients with major radiation injury had a hazard ratio for appearance of focal deficits of 7.042 (p?=?0.04), of intracranial hypertension 2.857 (p?=?0.025), hemorrhage into occluded nidus 9.009 (p?=?0.079), appearance of new seizures not significant.

Conclusions

Major radiation injury is frequent and increases the risk of neurological complications. Its late appearance implies that current follow-up protocols need to be extended in time.     

Endovascular treatment of brain arteriovenous malformations using a liquid embolic agent: results of a prospective, multicentre study (BRAVO)

Objectives

To evaluate the safety and efficacy of a new liquid embolic agent in brain arteriovenous malformation (bAVMs) embolisation.

Methods

A prospective, multicentre series was conducted at 11 interventional centres in Europe to evaluate embolisation of bAVMs with the new liquid embolic agent. Technical conditions, complications, clinical outcome and anatomical results were independently analysed.

Results

From December 2005 to December 2008, 117 patients (72 male; 45 female, aged 18–75 years) were included. Clinical presentation was mostly haemorrhage (34.2 %) and seizures (28.2 %). Most AVMs were located in the brain hemispheres (85.5 %). AVMs were <3 cm in 52.1 % of patients and ≥3 cm in 47.9 %. Morbidity was observed in 6/117 patients (5.1 %), related to haemorrhagic events in 2 cases and non-haemorrhagic complications in 4 cases. Five patients (4.3 %) died in relation to the treatment (bleeding in 4 patients and extensive venous thrombosis in 1). Complete occlusion of the AVM by embolisation alone was obtained in 23.5 % of patients. Complementary treatment was performed in 82.3 % of patients with partial AVM occlusion, mostly radiosurgery.

Conclusions

In this prospective, multicentre, European, observational series, the new liquid embolic agent proved to be suitable for BAVM embolisation, with acceptable morbidity and mortality and good efficacy.

Key Points

? Numerous interventional techniques have been used to embolise brain arteriovenous malformations (AVMs). ? This prospective multicentre study demonstrates the suitability of a liquid embolic agent. ? The safety of treatment using Onyx is acceptable. ? Such embolisation leads to complete AVM occlusion in 23.5 % of patients.     

Imaging of adult astrocytic brain tumours with 7 T MRI: preliminary results

Purpose

In this study tumour vascularity and necrosis of intracranial astrocytomas were compared using 7 T and 1.5 T magnetic resonance imaging (MRI).

Methods

Fifteen patients with histologically proven astrocytomas (WHO grades II–IV) were prospectively examined at 1.5 T (Magnetom Espree or Sonata) and 7 T (Magnetom 7 T, Siemens, Erlangen, Germany) with T2*-w (weighted), T1-w with (only a subset of five patients at 7 T) and without contrast medium, T2-w and proton-density (PD)-w MRI. Clinically used 1.5 T sequences were adapted to 7 T. Histological findings and T2*-w MR images at both field strengths were compared for the presence of assumed tumour microvascularity and necrosis. Two diffusely infiltrating astrocytomas, four anaplastic astrocytomas and nine glioblastomas were included.

Results

T2*-w images depicted susceptibility patterns representing presumed tumour microvascularity in 8 out of 15 (53%) gliomas at 7 T compared with 5 out of 15 (33%) gliomas at 1.5 T. Compared with 1.5 T MRI three additional necrotic tumour areas were depicted only on 7 T T2- and T2*-w images of one glioblastoma. On T1-w MR images, contrast enhancement of five out of five glioblastomas was similar at both field strengths.

Conclusion

7 T gradient-echo sequences provide excellent image contrast of presumed microvasculature and necrosis in astrocytomas.     

Chevron-type medial malleolar osteotomy: a functional, radiographic and quantitative T2-mapping MRI analysis

Purpose

The purpose of this study was to retrospectively evaluate a large series of patients for functional, radiographic and MRI outcomes after a Chevron-type medial malleolar osteotomy.

Methods

Sixty-two patients underwent a Chevron-type medial malleolar osteotomy with a median follow-up of 34.5 months. Standard digital radiographs were used to determine bony union and the angle of the osteotomy relative to the longitudinal axis of the tibia. Morphologic and quantitative T2-mapping MRI was also analysed in 32 patients.

Results

Fifty-eight patients (94 %) reported being asymptomatic at the site of the medial malleolar osteotomy. The median time to healing on standard radiograph was 6 weeks (range, 4–6 weeks) with an angle of 31.7° ± 6.9°. Quantitative T2-mapping MRI analysis demonstrated that the deep half of interface repair tissue had relaxation times that were not significantly different from normal tibial cartilage. In contrast, interface repair tissue in the superficial half demonstrated significant prolongation from normal relaxation time values, indicating a more fibrocartilaginous repair. Four patients (6 %) reported pain post-operatively.

Conclusion

A Chevron-type medial malleolar osteotomy demonstrates satisfactory healing and fixation, with fibrocartilaginous tissue evident superficially at the osteotomy interface. Further investigation is warranted in the form of longitudinal study to assess the long-term outcomes of medial malleolar osteotomy.

Level of evidence

IV.     

High-resolution MRI predicts steroid injection response in carpal tunnel syndrome patients

Objectives

To correlate median nerve T2 signal and shape at the carpal tunnel with steroid injection (SI) response in carpal tunnel syndrome (CTS) patients.

Methods

One hundred and sixty-three CTS wrists of 92 consecutive patients who were scheduled to undergo SI were prospectively evaluated with 3-T magnetic resonance imaging (MRI) and a nerve conduction study. All patients underwent axial high-resolution T2-weighted MRI (in-plane resolution of 0.25?×?0.25 mm). The CTS wrists were classified into three groups according to the nerve T2 signal and the flattening ratio at the hook of hamate level: group 1, high and oval; group 2, high and flat; group 3, low and flat. Clinical response to SI was evaluated at 6 months after injection.

Results

One hundred and thirteen of the 163 wrists (69.3 %) responded well to SI. The percentage of improvement was 81.7 % (49/60) in group 1, 69.9 % (51/73) in group 2, and 43.3 % (13/30) in group 3 (P?<?0.01). On stepwise logistic regression analysis high-resolution MRI was the only significant independent factor for SI response in CTS patients (P?<?0.01).

Conclusions

High-resolution MRI correlates well with SI response in CTS patients and seems useful for predicting SI response.

Key Points

? MRI may help determine appropriate care in carpal tunnel syndrome. ? MRI helps in therapeutic decision-making whenever steroid injection is considered. ? T2 signal decrease of the median nerve correlates with poor outcome. ? T2 signal decrease of median nerve may reflect fibrosis and amyloid deposition.     

Ultrahochfeld-MR-Tomographie in der Kardiologie

Clinical/methodical issue

This involves high spatial resolution cardiac imaging with ultrahigh magnetic fields (7 T) and clinically acceptable image quality.

Standard radiological methods

Cardiovascular magnetic resonance imaging (MRI) at a field strength of 1.5 T using a spatial resolution of (2?×?2?×?6–8) mm³.

Methodical innovations

Cardiac MRI at ultrahigh field strength makes use of multitransmit/receive radiofrequency (RF) technology and development of novel technology that utilizes the traits of ultrahigh field MRI.

Performance

Enhanced spatial resolution which is superior by a factor of 6–10 to what can be achieved by current clinical cardiac MRI. The relative spatial resolution (pixels per anatomical structure) comes close to what can be accomplished by current cardiac MRI in small rodents.

Achievements

Feasibility studies demonstrate the gain in spatial resolution at 7.0 T due to the sensitivity advantage inherent to ultrahigh magnetic fields.

Practical recommendations

Please stay tuned and please put further weight behind the solution of the remaining technical problems of cardiac MRI at 7.0 T.     

Comparison of 1.5- and 3-T MR imaging for evaluating the articular cartilage of the knee

Purpose

The aim of this prospective study was to compare routine MRI scans of the knee at 1.5 and 3 T obtained in the same individuals in terms of their performance in the diagnosis of cartilage lesions.

Methods

One hundred patients underwent MRI of the knee at 1.5 and 3 T and subsequent knee arthroscopy. All MR examinations consisted of multiplanar 2D turbo spin-echo sequences. Three radiologists independently graded all articular surfaces of the knee joint seen at MRI. With arthroscopy as the reference standard, the sensitivity, specificity, and accuracy of 1.5- and 3-T MRI for detecting cartilage lesions and the proportion of correctly graded cartilage lesions within the knee joint were determined and compared using resampling statistics.

Results

For all readers and surfaces combined, the respective sensitivity, specificity, and accuracy for detecting all grades of cartilage lesions in the knee joint using MRI were 60, 96, and 87 % at 1.5 T and 69, 96, and 90 % at 3 T. There was a statistically significant improvement in sensitivity (p < 0.05), but not specificity or accuracy (n.s.) for the detection of cartilage lesions at 3 T. There was also a statistically significant (p < 0.05) improvement in the proportion of correctly graded cartilage lesions at 3 T as compared to 1.5 T.

Conclusion

A 3-T MR protocol significantly improves diagnostic performance for the purpose of detecting cartilage lesions within the knee joint, when compared with a similar protocol performed at 1.5 T.

Level of evidence

III.     

Assessing liver function by liver enhancement during the hepatobiliary phase with Gd-EOB-DTPA-enhanced MRI at 3 Tesla

Objectives

The purpose of this study was to evaluate the usefulness of Gd-EOB-DTPA-enhanced 3-T MRI to determine the hepatic functional reserve expressed by the model for end-stage liver disease (MELD) score.

Methods

A total of 121 patients with normal liver function (NLF; MELD score?≤?10) and 29 patients with impaired liver function (ILF; MELD score?>?10) underwent contrast-enhanced MRI with a hepatocyte-specific contrast agent at 3T. T1-weighted volume interpolated breath-hold examination (VIBE) sequences with fat suppression were acquired before and 20 min after contrast injection. Relative enhancement (RE) between plain signal intensity and contrast-enhanced signal intensity was calculated and was used to determine Gd-EOB-DTPA uptake into the liver parenchyma for patients with different MELD scores.

Results

RE differed significantly (p?≤?0.001) between patients with NLF (87.2?±?29.5 %) and patients with ILF (45.4?±?26.5 %). The optimal cut-off value for RE to differentiate NLF from ILF was 47.7 % (AUC 0.87). This cut-off value showed a sensitivity of 82.8 % and a specificity of 92.7 % for the differentiation of the analysed groups.

Conclusion

Gd-EOB-DTPA uptake in hepatocytes is strongly affected by liver function. Gd-EOB-DTPA-enhanced MRI and assessment of RE during the hepatobiliary phase (HBP) may serve as a useful image-based test in liver imaging for determining regional and global liver function.

Key points

• Hepatic uptake of Gd-EOB-DTPA is strongly affected by liver function.
• Relative enhancement during HBP in GD-EOB-DTPA MRI correlates with the MELD score.
• Assessment of relative enhancement may help improve treatment in routine clinical practice.

     

Ruptured brain arteriovenous malformations associated with aneurysms: safety and efficacy of selective embolization in the acute phase of hemorrhage

Introduction

The impact of targeted embolization of ruptured cerebral arteriovenous malformation (AVM)-associated arterial aneurysms in the acute phase of bleeding is not well known. The objective of our study was to analyze the safety and efficacy of this treatment strategy with special emphasis on its protective effect against rebleeding.

Methods

From a prospective database, all patients presenting between December 2005 and March 2012 with a ruptured cerebral AVM associated with arterial aneurysms contiguous to the hemorrhage were selected. Hemorrhagic stroke severity and clinical outcome were measured using, respectively, Glasgow Coma Scale (GCS) and modified Rankin Scale (mRS) scores.

Results

Twenty-five patients with ruptured cerebral AVMs associated with 31 arterial aneurysms contiguous with the hemorrhage were included. In the first group of 17 patients, the mean time to treatment was 30.1 h, while in the second group with 1 patient in poor initial clinical conditions and 7 admitted 7 to 28 days after bleeding, it was 17 days. All arterial aneurysms were totally occluded. Four patients presented rebleeding before treatment (mean interval 9.6 days) and four had rebleeding after treatment (mean interval 8.25 months). At a mean follow-up of 56 months, 21 patients were alive (19 mRS?≤?2, 2 mRS?>?2). Three patients died 2 days, 9 days, and 2 months after bleeding and another died of rebleeding of her residual AVM 19 months after treatment. Treatment-related morbidity and mortality were, respectively, 4 and 0 %.

Conclusion

Selective embolization of arterial aneurysms associated with ruptured AVMs is a safe procedure and could lower the immediate risk of rebleeding.     

Isolated cerebral susceptibility artefacts in patients with malignant melanoma: metastasis or not?

Objective

While staging patients with malignant melanoma, cerebral susceptibility artefacts on T2*-weighted/susceptibility-weighted imaging (SWI) sequences without a correlate on contrast-enhanced T1-weighted images can be confusing. Without intravenous contrast enhancement, cavernomas, microhaemorrhages and melanin-containing metastases represent possible differential diagnoses for these findings. The purpose of this study was to find out, how often such lesions correspond to metastases.

Methods

Brain MR images (1.5 T) of 408 patients with malignant melanoma but without cerebral metastases in the initial staging by MRI were reviewed retrospectively. Eighteen patients (5 female, 13 male) with malignant melanoma and signal intensity loss on T2*/SWI were included in our study. The average observation period was 19.6 months (6–46 months, 2006–2009).

Results

In each of these 18 patients between one and seven hypointense lesions on T2*/SWI were found. None of these lesions developed into metastasis.

Conclusion

Focal areas of susceptibility artefacts in the brain parenchyma without corresponding abnormalities in contrast-enhanced T1 weighted images are unlikely to represent brain metastases.

Key Points

? In melanoma patients early diagnosis of metastatic brain lesions is mandatory. ? Melanin content and haemorrhage are potential reasons for MRI characteristics of melanoma metastases. ? Susceptibility-weighted MRI visualises melanin and blood products. ? Isolated cerebral susceptibility artefacts do not convert into melanoma metastases. ? SWI/T2* sequences cannot replace Gd-enhanced sequences.     

Assessment of irradiated brain metastases using dynamic contrast-enhanced magnetic resonance imaging

Introduction

The purpose of this study was to evaluate the effect of stereotactic radiosurgery (SRS) on cerebral metastases using the transfer constant (K _trans) assessed by dynamic contrast-enhanced (DCE) MRI. Furthermore, we aimed to evaluate the ability of K _trans measurements to predict midterm tumor outcomes after SRS.

Methods

The study received institutional review board approval, and informed consent was obtained from all subjects. Twenty-six adult patients with a total of 34 cerebral metastases underwent T1-weighted DCE MRI in a 1.5-T magnet at baseline (prior to SRS) and 4–8 weeks after treatment. Quantitative analysis of DCE MRI was performed by generating K _trans parametric maps, and region-of-interest-based measurements were acquired for each metastasis. Conventional MRI was performed at least 16 weeks after SRS to assess midterm tumor outcome using volume variation.

Results

The mean (±SD) K _trans value was 0.13?±?0.11 min^?1 at baseline and 0.08?±?0.07 min^?1 after 4–8 weeks post-treatment (p?<?0.001). The mean (±SD) total follow-up time was 7.9?±?4.7 months. Seventeen patients (22 lesions) underwent midterm MRI. Of those, nine (41 %) lesions had progressed at the midterm follow-up. An increase in K _trans after SRS was predictive of tumor progression (hazard ratio?=?1.50; 95 % CI?=?1.16–1.70, p?<?0.001). An increase of 15 % in K _trans showed a sensitivity of 78 % and a specificity of 85 % for the prediction of progression at midterm follow-up.

Conclusion

SRS was associated with a reduction of K _trans values of the cerebral metastases in the early post-treatment period. Furthermore, K _trans variation as assessed using DCE MRI may be helpful to predict midterm outcomes after SRS.     

Feasibility of high-resolution pituitary MRI at 7.0 tesla

Objectives

Since the pituitary gland measures 3-8 mm, imaging with the highest possible spatial resolution is important for the detection of even smaller lesions such as those seen in Cushing's disease. In the current feasibility study, we tested a multi-sequence MRI protocol to visualize the pituitary gland in high resolution at 7.0 Tesla (7.0 T).

Methods

Ten healthy volunteers were examined with a 7.0 T pituitary gland protocol. The protocol consisted of a T1-weighted magnetization-prepared inversion recovery (MPIR) turbo spin-echo (TSE) sequence and a T2-weighted TSE sequence. Additionally, this protocol was tested in five patients with clinical and biochemical suspicion of a microadenoma.

Results

The dedicated protocol was successful in visualizing normal pituitary anatomy. At 7.0 T compared to 1.5 T, four times as many slices covered the pituitary gland in sagittal and coronal direction. In three patients, a lesion was diagnosed at 7.0 T, and was confirmed by histopathology to be a microadenoma.

Conclusion

Head-to-head comparisons of 7.0 T with 1.5 T and 3.0 T are needed with larger samples of patients and with imaging times feasible for clinical settings. However, the current study suggests that high-resolution 7.0 T MRI of the pituitary gland may provide new perspectives when used as a second-line diagnostic examination in the specific context of Cushing's disease.

Key Points

? 7.0 T MRI enables ultra-high-resolution imaging of the pituitary gland. ? 7.0 T MRI is appropriate to visualize normal pituitary gland anatomy. ? The pituitary protocol consists of a T ₁ -MPIR-TSE and a T ₂ -TSE sequence. ? In four patients, a suspected ACTH-producing microadenoma was visualized at 7.0 T. ? Histopathology confirmed three of four lesions to be ACTH-producing microadenomas.     

Hypofractionated stereotactic radiotherapy of acoustic neuroma

Purpose

The goal of this work was to evaluate toxicity and local control following hypofractionated stereotactic radiation treatment with special focus on changes in tumor volume and hearing capacity.

Patients and methods

In all, 29 patients with unilateral acoustic neuroma were treated between 2001 and 2007 within a prospective radiation protocol (7?×?4 Gy ICRU dose). Median tumor volume was 0.9 ml. Follow-up started at 6 months and was repeated annually with MRI volumetry and audiometry. Hearing preservation was defined as preservation of Class A/B hearing according to the guidelines of the American Academy of Otolaryngology (1995).

Results

No patient had any intervention after a median imaging follow-up of 89.5 months, one patient showed radiological progression. Transient increase of tumor volume developed in 17/29 patients, whereas 22/29 patients (75.9?%) presented with a volume reduction at last follow-up. A total of 21 patients were eligible for hearing evaluation. Mean pure tone average (PTA) deteriorated from 39.3 to 65.9 dB and mean speech discrimination score (SDS) dropped from 74.3 to 38.1?%. The 5-year actuarial Class A/B hearing preservation rate was 50.0?±?14.4?%.

Conclusion

Radiation increases only minimally, if at all, the hearing deterioration which emerges by observation alone. Presbyacusis is not responsible for this deterioration. Transient tumor enlargement is common. Today radiation of small- and medium-sized acoustic neuroma can be performed with different highly conformal techniques as fractionated treatment or single low-dose radiosurgery with equal results regarding tumor control, hearing preservation, and side effects. Hypofractionation is more comfortable for the patient than conventional regimens and represents a serious alternative to frameless radiosurgery.     

3-T breast magnetic resonance imaging in patients with suspicious microcalcifications on mammography

Objective

To investigate the diagnostic value of 3-Tesla (T) breast MRI in patients presenting with microcalcifications on mammography.

Methods

Between January 2006 and May 2009, 123 patients with mammographically detected BI-RADS 3–5 microcalcifications underwent 3-T breast MRI before undergoing breast biopsy. All MRIs of the histopathologically confirmed index lesions were reviewed by two breast radiologists. The detection rate of invasive carcinoma and ductal carcinoma in situ (DCIS) was evaluated, as well as the added diagnostic value of MRI over mammography and breast ultrasound.

Results

At pathology, 40/123 (33 %) lesions proved malignant; 28 (70 %) DCIS and 12 (30 %) invasive carcinoma. Both observers detected all invasive malignancies at MRI, as well as 79 % (observer 1) and 86 % (observer 2) of in situ lesions. MRI in addition to conventional imaging led to a significant increase in area under the receiver operating characteristic (ROC) curve from 0.67 (95 % CI 0.56–0.79) to 0.79 (95 % CI 0.70–0.88, observer 1) and to 0.80 (95 % CI 0.71–0.89, observer 2), respectively.

Conclusions

3-T breast MRI was shown to add significant value to conventional imaging in patients presenting with suspicious microcalcifications on mammography.

Key points

? 3-T MRI is increasingly used for breast imaging in clinical practice. ? On 3-T breast MRI up to 86 % of DCIS lesions are detected. ? 3-T MRI increases the diagnostic value in patients with mammographically detected microcalcifications.     

Assessment of the treatment response of spinal meningiomas after radiosurgery focusing on serial MRI findings

Purpose

This study evaluated the response of spinal meningiomas to treatment, by monitoring changes in magnetic resonance imaging (MRI) findings after stereotactic radiosurgery (SRS).

Materials and methods

Serial follow-up MRIs of 11 patients with spinal meningiomas who underwent SRS were retrospectively reviewed. Changes in tumor volume, T2 signal intensity (T2SI), and contrast enhancement were evaluated.

Results

The mean MRI follow-up period was 46.9 months (range 13–108 months). The local tumor control rate was 100 % in overall tumor volume, although boost SRS was performed for marginal recurrence in case 8 and rapid decompression in case 5. Seven tumors showed decreased T2SI. Each of the remaining four tumors showed variable T2SIs. In most tumors, the enhancement patterns did not change. Two of three patients with en plaque type meningiomas showed increased intramedullary T2SI, thought to be due to compressive myelopathy and peritumoral edema.

Conclusions

SRS resulted in successful local tumor control in all patients, although the follow-up period was not long. Changes in T2SI and contrast enhancement patterns of the tumors were evaluated on serial MRI. In addition, close follow-up with MRI is desirable to monitor intramedullary signal changes in cases of spinal meningiomas with a wider contact area with the spinal cord.

     

Arthroscopic inside-out repair of complete radial tears of the meniscus with a fibrin clot

Purpose

To report on the results of 12 complete radial tears of the meniscus treated using arthroscopic inside-out repair with fibrin clots, the results showed good meniscal healing and excellent clinical outcomes.

Methods

From 2007 to 2009, 12 patients with complete radial tears of the meniscus were treated by arthroscopic inside-out repair with fibrin clots. In all patients, the International Knee Documentation Committee (IKDC) subjective knee form and Lysholm score were determined pre- and post-operatively. We performed magnetic resonance imaging (MRI) and if indicated, we performed a second-look arthroscopic examination.

Results

At a mean of 30 ± 4 postoperative months, the Lysholm score and IKDC subjective knee score had improved from 65 ± 6 and 57 ± 7 to 94 ± 3 and 92 ± 3, respectively. Eleven of 12 cases showed complete healing on follow-up MRI. Six of 7 patients undergoing a second-look arthroscopic examination had healed completely.

Conclusion

This study shows successful meniscal repairs using fibrin clots in complete radial tears. This surgical procedure appears to be a good treatment method for complete radial tear of the meniscus.

Level of evidence

Case series, Level IV.     

Treatment of post-traumatic osteochondral lesions of the talus: a four-step approach

Purpose

The purpose of this retrospective study was to assess the treatment of post-traumatic osteochondral lesions (OCLs) of the ankle with a four-step protocol.

Methods

Thirty-eight patients with at least one MRI-documented OCL of the ankle were treated from 2004 to 2010. Median age at surgery was 39 years (range: 18–52). Mean lesion size was 1.0 cm² (SD: 0.2). All patients underwent a four-step surgical procedure including synovectomy, debridement and microfractures of the OCL, capsular shrinkage, and bracing and non-weightbearing for 21 days. Clinical assessment included objective examination, the AOFAS ankle and hindfoot scoring system, Karlsson-Peterson score, Tegner activity level, and Sefton articular stability scale. MRI scans were taken 18 months after surgery in all patients.

Results

Follow-up examination at an average of 4 years (SD: 1.1) after surgery showed significant improvement of all variables compared to pre-operative values (P < 0.05). Most patients rated their outcome as good/excellent. MRI scans taken 18 months after surgery documented completely repaired lesion in 27 ankles, slight bone marrow oedema with partially repaired defect in 9 patients, and visible defect in 2 ankles.

Conclusion

Based on the present results, we propose a comprehensive four-step protocol as a safe and clinically effective treatment option in patients with post-traumatic OCLs of the ankle.

Level of evidence

Retrospective case series, Level IV.     

MRI displays involvement of the temporalis muscle and the deep temporal artery in patients with giant cell arteritis

Purpose

To assess deep temporal artery and temporalis muscle involvement in patients with giant cell arteritis (GCA).

Material and methods

Ninety-nine patients who received magnetic resonance imaging (MRI) and superficial temporal artery biopsy (TAB) were included in this study. Patients with positive TAB (n?=?61) were defined as GCA patients, those with negative TAB (n?=?38) as the GCA-negative reference group. Contrast-enhanced T1w-images were acquired utilizing 1.5 T and 3 T MRI. Two radiologists assessed the images. Mural contrast-hyperenhancement and wall thickening of the deep temporal artery and hyperenhancement of the muscle were defined as inflammation. MRI results were correlated with jaw claudication in 70 patients.

Results

The two observers found temporalis muscle involvement in 19.7 % (n?=?12) and 21.3 % (n?=?13) of GCA patients. It occurred bilaterally in 100 %. Specificities were 92/97 % and sensitivities were 20/21 %. Deep temporal artery involvement was found in 34.4 % (n?=?21) and 49.2 % (n?=?30) and occurred bilaterally in 80/90.5 %. Specificities were 84/95 % and sensitivities were 34/49 %. Both structures were affected simultaneously in 18/21.3 %. Jaw claudication correlated moderately with inflammation of the temporalis muscle (r?=?0.31; p?Conclusion MRI visualizes changes in the temporalis muscle and the deep temporal artery in GCA. Moderate correlation of clinical symptoms with MRI results was observed.

Key Points

? Approximately 20 % of GCA patients presented with temporalis muscle inflammation. ? A total of 34-49 % of GCA patients presented with vasculitis of the deep temporal artery. ? In approximately 20 % of GCA patients, both structures were simultaneously involved. ? Involvement of both structures correlated moderately with presence of jaw claudication. ? MRI is a suitable tool for the assessment of vasculitis and muscle inflammation.     

Susceptibility-weighted angiography for the detection of high-flow intracranial vascular lesions: preliminary study

Objectives

Susceptibility-weighted magnetic resonance imaging (MRI) sequences may demonstrate various signal intensities of draining veins in cases of high-flow vascular malformation (HFVM), including arteriovenous malformation (AVM) and dural arteriovenous fistula (dAVF). Our objective was to evaluate susceptibility-weighted angiography (SWAN) for the detection of HFVM.

Methods

Fifty-eight consecutive patients with a suspected intracranial vascular malformation were explored with SWAN and post-contrast MRI sequences at 3 T. The diagnosis of slow-flow vascular malformation (SFVM), including developmental venous anomaly (DVA) or brain capillary telangiectasia (BCT), was based on MRI. Patients with suspected HFVM underwent digital subtraction angiography (DSA). SWAN images were analysed by three blinded readers according to a three-point scale of the venous signal.

Results

Thirty-one patients presented 35 SFVM (26 DVA and 9 BCT) that systematically appeared hypointense on SWAN images. In patients with atypical MRI findings, DSA revealed one patient with an atypical DVA and 26 patients with HFVM (22 AVM and 4 dAVF). SWAN revealed at least one venous hyperintensity in all patients with HFVM. Agreement between readers was excellent.

Conclusions

SWAN appears reliable for characterising blood flow dynamics in brain veins. In clinical practice, SWAN can routinely rule out HFVM in patients with atypical brain veins.

Key Points

? Susceptibility-weighted angiography (SWAN) offers new perspectives for detecting intracranial vascular malformations. ? SWAN sequence provides non-invasive characterisation of blood flow dynamics. ? SWAN can differentiate between high and slow flowing venous blood. ? SWAN can routinely rule out high-flow vascular malformations.     

Diagnostic accuracy and patient acceptance of MRI in children with suspected appendicitis

Objective

To compare magnetic resonance imaging (MRI) and ultrasound in children with suspected appendicitis.

Methods

In a single-centre diagnostic accuracy study, children with suspected appendicitis were prospectively identified at the emergency department. All underwent abdominal ultrasound and MRI within 2 h, with the reader blinded to other imaging findings. An expert panel established the final diagnosis after 3 months. We evaluated the diagnostic accuracy of three imaging strategies: ultrasound only, conditional MRI after negative or inconclusive ultrasound, and MRI only. Significance between sensitivity and specificity was calculated using McNemar’s test statistic.

Results

Between April and December 2009 we included 104 consecutive children (47 male, mean age 12). According to the expert panel, 58 patients had appendicitis. The sensitivity of MRI only and conditional MRI was 100 % (95 % confidence interval 92–100), that of ultrasound was significantly lower (76 %; 63–85, P?<?0.001). Specificity was comparable among the three investigated strategies; ultrasound only 89 % (77–95), conditional MRI 80 % (67–89), MRI only 89 % (77–95) (P values 0.13, 0.13 and 1.00).

Conclusion

In children with suspected appendicitis, strategies with MRI (MRI only, conditional MRI) had a higher sensitivity for appendicitis compared with a strategy with ultrasound only, while specificity was comparable.

Key Points

? In children, MRI has a higher sensitivity for appendicitis than ultrasound. ? Ultrasound followed by MRI in negative or inconclusive findings is accurate. ? The tolerance for ultrasound and MRI in children is comparable. ? MRI can be performed in children in an emergency setting.