FDG PET/CT imaging in the diagnosis of osteomyelitis in the diabetic foot

Purpose

Osteomyelitis, the most serious complication of the diabetic foot, occurs in about 20?% of patients. Early diagnosis is crucial. Appropriate treatment will avoid or decrease the likelihood of amputation. The objective of this study was to assess the value of FDG PET/CT in diabetic patients with clinically suspected osteomyelitis.

Methods

Enrolled in this prospective study were 39 consecutive diabetic patients (29 men and 10 women, mean age 57?years, range 28–71?years) with 46 suspected sites of foot infection. Of these 39 patients, 38 had type 2 and 1 type 1 diabetes for 4–25?years, and 28 were receiving treatment with insulin. FDG PET/CT was interpreted for the presence, intensity (SUVmax) and localization of increased FDG foci. Final diagnosis was based on histopathology and bacteriology of surgical samples, or clinical and imaging follow-up.

Results

Osteomyelitis was correctly diagnosed in 18 and excluded in 21 sites. Of 20 lesions with focal bone FDG uptake, 2 were false-positive with no further evidence of osteomyelitis. Five sites of diffuse FDG uptake involving more than one bone on CT were correctly diagnosed as diabetic osteoarthropathy. FDG PET/CT had a sensitivity, specificity and accuracy of 100?%, 92?% and 95?% in a patient-based analysis and 100?%, 93?% and 96?% in a lesion-based analysis, respectively, for the diagnosis of osteomyelitis in the diabetic foot.

Conclusion

FDG PET/CT was found to have high performance indices for evaluation of the diabetic foot. The PET component identified FDG-avid foci in sites of acute infection which were precisely localized on fused PET/CT images allowing correct differentiation between osteomyelitis and soft-tissue infection.     

The diabetic foot: Charcot joint and osteomyelitis

Foot problems are common causes of disability in diabetic patients with as many as 25% expected to develop severe foot or leg problems during their lifetimes. Although skin ulceration is the most frequent problem, bones may also be involved in two different clinical conditions: osteomyelitis and Charcot osteoarthropathy. Osteomyelitis causes complications in up to one third of diabetic foot infections and is due to direct contamination from a soft-tissue ulcer. Osteoarthropathy Charcot foot is a chronic and progressive disease of the bone and joints. Both osteomyelitis and Charcot joint are conditions with an increased risk of lower limb amputation, both may have a successful outcome when recognized and treated in the early stages. The major diagnostic difficulty is in distinguishing bone infection (osteomyelitis) from non-infectious neuropathic bony disorders as in osteoarthropathy Charcot foot. An additional difficulty is found when a bone infection superimposes a Charcot osteopathy. This condition, which can be clinically suspected when foot ulceration appears in Charcot foot, needs to be diagnosed because it implies a different therapeutic strategy. This article aims to summarize both these two clinical conditions and give indications to make a timely and correct diagnosis.     

Diagnosis of moyamoya disease using 3-T MRI and MRA: value of cisternal moyamoya vessels

Introduction

The purpose of this study was to propose new magnetic resonance (MR) criteria of diagnosing moyamoya disease (MMD) from cisternal moyamoya vessels (MMVs) on 3-T magnetic resonance imaging (MRI)/magnetic resonance angiography (MRA) and compare the diagnostic accuracy of the existing MR criteria and the proposed MR criteria.

Methods

Participants comprised 20 consecutive patients with MMD (4 males, 16 females) diagnosed clinically using conventional angiography and 20 controls (13 male and 7 female arteriosclerosis patients). In these participants, 3-T MRI/MRA was evaluated by the existing MR criteria, which use MMVs in the basal ganglia, and the proposed MR criteria, which use cisternal MMVs, and then these two criteria were statistically compared by McNemar’s test.

Results

Diagnostic accuracy was 62.5% with the existing MR criteria and 97.5% with the proposed MR criteria. The proposed MR criteria was more sensitive (1.00) than the existing MR criteria (0.45), but less specific (0.95) than the existing MR criteria (1.00).

Conclusion

The proposed MR criteria using cisternal MMVs showed significantly higher diagnostic accuracy than the existing MR criteria. We believe that our proposed MR criteria will be beneficial for diagnosing MMD.     

Indium-111-leukocyte/technetium-99m-MDP bone and magnetic resonance imaging: difficulty of diagnosing osteomyelitis in patients with neuropathic osteoarthropathy

Fourteen patients (16 sites) with clinical and/or radiographic evidence of neuropathic osteoarthropathy (Charcot joints) were evaluated with combined indium-111-leukocyte (111In-WBC) and technetium-99m-methylene diphosphonate (99mTc-MDP) bone imaging for suspected osteomyelitis. Magnetic resonance (MR) images were obtained in seven patients. Using a positive bone culture as the criterion for the presence of osteomyelitis, there were four true-positive studies, six true-negative sites, and one false-negative 111In-WBC study. Five of 16 sites (31%) had false-positive 111In-WBC uptake at noninfected sites. There were four true-positive and three false-positive MR studies. All false-positives showed at least moderately abnormal findings by both techniques at sites of rapidly progressing osteoarthropathy of recent onset. In this preliminary study, both techniques appear to be sensitive for detection of osteomyelitis, and a negative study makes osteomyelitis unlikely. However, the findings of 111In-WBC/99mTc-MDP and MR images at sites of rapidly progressing, noninfected neuropathic osteoarthropathy may be indistinguishable from those of osteomyelitis.     

Patency of runoff detected by MR angiography at 3.0 T with cuff-compression: a predictor of successful endovascular recanalization below the knee

Objectives

Our aim was to assess the reliability of detecting distal runoff vessels using contrast-enhanced MR angiography (CE-MRA) that were occult on digital subtraction angiography (DSA) for predicting the outcome of endovascular recanalization (ER).

Methods

This retrospective analysis comprised 63 patients with diabetes (98 limbs) who underwent ER for infrapopliteal lesions. Before ER, they underwent CE-MRA and DSA for peripheral arterial disease; runoff vessels were detected with CE-MRA, but not with DSA. Immediate and follow-up postoperative outcomes were assessed. Univariate analysis was performed to identify variables associated with successful ER.

Results

Successful ER was achieved in 85.7 % of limbs, and runoff score was significantly lower than in failure limbs (5.1?±?1.1 vs. 6.2?±?1.3; P?Restenosis/occlusion rate was higher for patients with CLI at 12 months (48.8 % vs. 96.3 % in claudication; P?P?Conclusion Runoff vessels detected using CE-MRA could indicate immediate success and better outcome of ER for infrapopliteal occlusions.

Key Points

? 3-T MRA with cuff compression displayed distal below-the-knee (BTK) runoffs better than DSA ? Detected runoffs indicate high recanalization rate and good clinical outcome ? Runoff display provides potential opportunity to perform other backup recanalization strategies     

Ewing sarcoma versus osteomyelitis: differential diagnosis with magnetic resonance imaging

Objective

To find and evaluate characteristic magnetic resonance imaging (MRI) patterns for the differentiation between Ewing sarcoma and osteomyelitis.

Materials and methods

We identified 28 consecutive patients referred to our department for MRI (1.5 T) of an unclear bone lesion with clinical symptoms suggestive of Ewing sarcoma or osteomyelitis. MRI scans were re-evaluated by two experienced radiologists, typical MR imaging features were documented and a diagnostic decision between Ewing sarcoma and osteomyelitis was made. Statistical significance of the association between MRI features and the biopsy-based diagnosis was assessed using Fisher’s exact test.

Results

The most clear-cut pattern for determining the correct diagnosis was the presence of a sharp and defined margin of the bone lesion, which was found in all patients with Ewing sarcoma, but in none of the patients with osteomyelitis (P?<?0.0001). Contrast enhancing soft tissue was present in all cases with Ewing sarcoma and absent in 4 patients with osteomyelitis (P?=?0.0103). Cortical destruction was found in all patients with Ewing sarcoma, 4 patients with osteomyelitis did not present any cortical reaction (P?=?0.0103). Cystic or necrotic areas were identified in 13 patients with Ewing sarcoma and in 1 patient with osteomyelitis (P?=?0.004). Interobserver reliability was very good (kappa?=?1) in Ewing sarcoma and moderate (kappa?=?0.6) in patients with osteomyelitis.

Conclusions

A sharp and defined margin, optimally visualized on T1-weighted images in comparison to short tau inversion recovery (STIR) images, is the most significant feature of Ewing sarcoma in differentiating from osteomyelitis.     

Utility of 99mTc-labelled antimicrobial peptide ubiquicidin (29-41) in the diagnosis of diabetic foot infection

Purpose

Detection of osteomyelitis beneath a diabetic foot ulcer is imperative for proper management; however, accurate and noninvasive diagnosis of osteomyelitis remains a challenge. Ubiquicidin 29-41 (UBI 29-41) is a synthetic antimicrobial peptide fragment reported to be highly infection-specific. ^99mTc-UBI 29-41 has recently been reported to be a promising radiotracer for infection imaging. The aim of this prospective study was to evaluate the utility of ^99mTc-UBI 29-41 scintigraphy in diabetic patients with suspected osteomyelitis of the foot.

Methods

Included in the study were 65 patients with type 2 diabetes mellitus and foot ulcer and with clinical suspicion of osteomyelitis . Each patient had a three-phase bone scan and a ^99mTc-UBI scan at 30 and 60 min after injection. The scan was considered to be consistent with osteomyelitis when the ^99mTc-UBI 29-41 uptake was concordant with the ^99mTc-MDP uptake. It was considered negative for osteomyelitis if there was no uptake of ^99mTc-UBI 29-41 or if ^99mTc-UBI 29-41 accumulated in an area not concordant with the abnormal uptake of ^99mTc-MDP on the bone scan. In the latter case a diagnosis of soft-tissue infection was made. Bone infection was confirmed by bone biopsy/culture and by clinical and radiological follow-up.

Results

Final analysis was done in 55 patients. Osteomyelitis was confirmed in 37 patients, and 18 patients were free of bone infection. ^99mTc-UBI 29-41 was positive in all 37 patients and with the bone scan as the reference for the bone identified all osteomyelitic foci (68 in total). ^99mTc-UBI 29-41 was negative for osteomyelitis in all 18 patients, and 17 of these patients were diagnosed with soft-tissue infection (^99mTc-UBI 29-41 accumulation without concordant abnormal uptake on bone scintigraphy). The sensitivity, specificity and accuracy of ^99mTc-UBI 29-41 scan in combination with three-phase bone scan for the diagnosis of osteomyelitis in diabetic foot was 100 %. Accuracy for soft-tissue infection was also 100 %. Maximum accumulation of the ^99mTc-UBI 29-41 with maximum target to background activity was observed in the infectious foci at 30 min after injection.

Conclusion

Tc-UBI 29-41 may be a useful agent for the accurate diagnosis of bone infection in diabetic foot because of the high accuracy demonstrated in this pilot study. It was able to differentiate between bone and soft-tissue involvement effectively in combination with a bone scan.     

Cerebral venous thrombosis: role of CT, MRI and MRA in the emergency setting

Purpose

It is often difficult to diagnose cerebral venous thrombosis (CVT), an uncommon condition that more frequently affects young subjects, is responsible for 1%–2% of strokes in adults and has a subtle clinic onset. The aim of this study was to evaluate the role of computed tomography (CT), magnetic resonance imaging (MRI) and MR venography in the emergency setting and to discuss the risk factors, clinical presentation, outcome and follow-up of this disease.

Materials and methods

We retrospectively studied 40 patients with CVT admitted to the emergency department between 1996 and 2006 and examined with unenhanced CT, MRI and MR venography. Fourteen patients also underwent digital subtraction angiography (DSA).

Results

Headache was the most common presenting feature (60%). Unenhanced CT showed typical signs (cord or empty delta sign) in 11 cases and nonspecific signs in the other cases. The diagnosis was achieved with MRI and MR venography in 38/40 cases (95%) and with DSA in 2/40 cases. All patients were treated with heparin. Five patients died, and only one of the remaining patients developed serious disability.

Conclusions

Knowledge of the CT, MRI and MR-venography signs of CVT is crucial and enables an early diagnosis and timely treatment with heparin in the majority of cases. DSA should be reserved for doubtful cases only.     

Diagnostic accuracy of contrast-enhanced MR angiography and unenhanced proton MR imaging compared with CT pulmonary angiography in chronic thromboembolic pulmonary hypertension

Objective

To evaluate the diagnostic accuracy of contrast-enhanced MR angiography (CE-MRA) and the added benefit of unenhanced proton MR angiography compared with CT pulmonary angiography (CTPA) in patients with chronic thromboembolic disease (CTE).

Methods

A 2?year retrospective study of 53 patients with chronic thromboembolic pulmonary hypertension who underwent CTPA and MRI for suspected pulmonary hypertension and a control group of 36 patients with no CT evidence of pulmonary embolism. The MRI was evaluated for CTE and the combined diagnostic accuracy of ce-MRA and unenhanced proton MRA was determined. CE-MRA generated lung perfusion maps were also assessed.

Results

The overall sensitivity and specificity of CE-MRA in diagnosing proximal and distal CTE were 98% and 94%, respectively. The sensitivity improved from 50% to 88% for central vessel disease when CE-MRA images were analysed with unenhanced proton MRA. The CE-MRA identified more stenoses (29/18), post-stenosis dilatation (23/7) and occlusions (37/29) compared with CTPA. The CE-MRA perfusion images showed a sensitivity of 92% for diagnosing CTE.

Conclusion

CE-MRA has high sensitivity and specificity for diagnosing CTE. The sensitivity of CE-MRA for visualisation of adherent central and lobar thrombus significantly improves with the addition of unenhanced proton MRA which delineates the vessel wall.     

Clinical outcome of angiosome-oriented infrapopliteal percutaneous transluminal angioplasty for isolated infrapopliteal lesions in patients with critical limb ischemia

PURPOSE

We aimed to evaluate the clinical usefulness and outcome of angiosome-oriented percutaneous transluminal angioplasty (IP-PTA) and its clinical outcome for isolated infrapopliteal lesions in diabetic critical limb ischemia.

METHODS

We retrospectively reviewed 70 patients (82 limbs) with diabetic critical limb ischemia who had localized disease at the level of the infrapopliteal artery. Patients underwent IP-PTA between January 2011 and December 2013 and were followed up for a mean of 13 months. The primary target arterial lesions were chosen according to the angiosome concept. We evaluated clinical findings, technical success, and patients’ clinical outcome. The angiographic outcome of IP-PTA was assessed using the angiosome score. We analyzed the relationship between the angiosome score and the amputation rate.

RESULTS

There were 69 anterior tibial artery (ATA) lesions, 70 posterior tibial artery (PTA) lesions, and 58 peroneal artery (PA) lesions. The primary target arteries were the ATA (n=43), PTA (n=26), PA (n=2), and ATA + PTA (n=11). We divided the treated limbs into target (n=63) and nontarget (n=19) groups. The overall initial technical success rate was 91.4%. Successful wound healing rates were 87.3% (55/63) and 47.3% (9/19) in the target and nontarget groups, respectively (P < 0.05).

CONCLUSION

Angiosome-oriented primary targeted IP-PTA shows a highly effective treatment outcome in diabetic critical limb ischemia. In cases with inadequate angioplastic results of the target artery, IP-PTA of the nontarget artery should be recommended to improve the limb salvage rates.Diabetic foot is defined as ulceration, infection, and/or destruction of the deep tissues of the foot in diabetic patients, associated with neurologic abnormalities and various degrees of peripheral vascular disease in the lower limb. The relationship between occurrence and healing of diabetic foot and peripheral vascular disease has been well investigated (1). The prevalence of diabetic foot has been reported to be between 2.8% and 10% of the diabetic population (1, 2). In Korea, 1.2% of diabetic patients have diabetic foot disease, and its prevalence has gradually increased to date (3). The risk of major amputation in patients with a diabetic foot ulcer is 8%–29%, and the mortality rate is 39%–80% in patients who have undergone major amputation (4).Critical limb ischemia is one of the most burdensome problems in the management of diabetic foot, and it is the leading cause of nontraumatic major amputations of the lower limbs. Infrapopliteal percutaneous transluminal angioplasty (IP-PTA) is a safe and effective treatment alternative to bypass surgery for diabetic critical limb ischemia (5). The angiosome concept was introduced by Ian Taylor in 1987 (6), and it has been considered a useful method for selecting the target artery that directly perfuses the diabetic foot wound. Several recent studies have reported that groups with angiosome-oriented target artery recanalization had better wound healing and limb salvage rates compared to groups with IP-PTA without the application of the angiosome concept (7, 8).The purpose of this study was to evaluate the clinical usefulness of angiosome-oriented IP-PTA and its clinical outcome for pure isolated infrapopliteal lesions in patients with diabetic critical limb ischemia and determine the significant angioplastic factors of IP-PTA that precede more successful treatment outcomes.     

MRI for therapy planning in patients with atrial septum defects

Purpose

The aim of this study was to determine the value of a combined magnetic resonance imaging (MRI) protocol including steady-state free precession (SSFP) imaging, phase-contrast measurements and contrast-enhanced MR angiography (CE-MRA) for presurgical or preinterventional diagnostic imaging in patients with suspected atrial septum defects.

Material and methods

Out of 65 MRI studies of patients with suspected atrial septum defects, 56?patients were included in the study. The atrial septum defects were identified on cine images. Velocity encoded flow measurements were used to determine shunt volumes, which were compared with invasive oxymetry in 24?patients. Contrast-enhanced MRI was used to assess the thoracic vessels in order to detect vascular anomalies. The findings were compared with the intraoperative results.

Results

A total of 24?patients with high shunt volumes were treated either surgically (16?patients) or interventionally (8?patients) and 32?patients with low shunt volumes did not require surgical or interventional treatment. The vascular anomaly, which in all cases was anomalous pulmonary venous return, was confirmed by the intraoperative findings. The type and location of atrial septal defects which required treatment, were confirmed intraoperatively or during the intervention. The results of shunt quantification by MRI showed a good correlation with the results of invasive oximetry (r=0.91, p <0.0001).

Conclusion

A combined MRI protocol including cine SSFP images, velocity-encoded flow measurements and CE-MRA is an accurate method for preoperative and preinterventional evaluation of atrial septum defects.     

Proton magnetic resonance spectroscopy in the evaluation of patients with acute Charcot neuro-osteoarthropathy

Objective

To evaluate whether bone marrow proton magnetic resonance spectroscopy (MRS) might provide a quantitative parameter able to assess disease activity in acute Charcot neuro-osteoarthropathy (CN).

Methods

Ten diabetic patients with stage 0 CN were prospectively evaluated at clinical onset and during treatment follow-up. The MRS lipid spectrum was analysed and a lipid polyunsaturation index (PUI) was calculated. Disease recovery was defined as the disappearance of bone marrow oedema as demonstrated on MRI short-tau-inversion-recovery (STIR) images. A 3-T MRI was used.

Results

Inter- and intra-individual PUI measurements generated reproducible results with approximately 7 % and 6 % variation respectively. Baseline PUI values were significantly higher in patients with acute CN compared with controls. Also, a significant positive correlation was observed between baseline PUI values and serum levels of IL-6 and TNF-α. During follow-up a gradual decrease in PUI was observed. The percentage reduction of PUI values at 3 months’ follow-up with respect to baseline values showed a negative correlation with recovery time.

Conclusions

Bone marrow MRS may provide a measurable index that allows progressive evaluation of disease activity in acute CN. MRS may be a complementary tool that can be used to guide clinicians in the management of acute CN patients.

Key Points

? Bone marrow MRS demonstrates lipid alterations in acute Charcot neuro-osteoarthropathy (CN). ? Bone marrow MRS allows disease activity in acute CN to be evaluated. ? MRS could become a new tool in the management of CN.     

Evaluation of diabetic foot osteomyelitis using probe to bone test and magnetic resonance imaging and their impact on surgical intervention

Objectives

To evaluate the role of probe to bone test (PTB) and magnetic resonance imaging (MRI) in assessing the surgical intervention in diabetic foot.

Study design

102 diabetic patients were included; 42 males and 60 females, mean age was 52 ± 6, all patients were subjected to PTB test followed by MRI, the presence of osteomyelitis was assessed in relation to histopathological examination.

Results

We had 80 (75.5%) feet of osteomyelitis, PTB test was true positive in 66 (82.5%), false negative in eight and false positive in 6 feet. MRI was true positive in 78, false positive in three and false negative in two feet. Other MRI finding include abscess in 37, tenosynovitis in 69, neuropathic changes in 20 feet, and all cases had cellulites. Sensitivity, specificity, PPV and NPV were 82.5%, 76.9%, 91.7%, and 58.8% for PTB test and 97.5%, 88.5%, 96.3% and 92% for MRI respectively.

Conclusion

PTB test is a simple, minimally invasive, low cost test and can be done at outpatient clinic. Its sensitivity and specificity are good when compared to those of MRI, but when we need to diagnose associated soft tissue infection and planning the surgical management MRI was the image of choice.     

Advanced virtual magnetic resonance imaging (MRI) techniques in neurovascular conflict: bidimensional image fusion and virtual cisternography

Purpose

The aim of this study was to evaluate the advantages and limits of virtual magnetic resonance techniques in planning surgery for microvascular decompression in patients with neurovascular conflict.

Materials and methods

Between December 2010 and December 2011, we prospectively observed 32 patients (30 with trigeminal neuralgia and two with hemifacial spasm), with a suspected clinical diagnosis of neurovascular conflict. To assess the contact between nerve and vessel, magnetic resonance imaging (MRI) by three-dimensional (3D) constructive interference in steady state (CISS) and high-resolution MR angiography (MRA) were performed in all cases. Moreover, we performed presurgical simulation of microvascular decompression using MR two-dimensional image fusion and virtual cisternography. The neuroradiological findings were compared with the surgical findings.

Results

In all cases, we demonstrated the anatomical relations between cranial nerves and offending vessels with an optimal correlation between radiological and surgical patterns.

Conclusions

Advanced virtual MRI techniques, such as image fusion and virtual cisternography, are able to depict the complex anatomical relationships between neural and vascular structures within the cisternal spaces of the skull base. These techniques can be considered an optimal presurgical tool to support traditional MRI evaluation of this region.     

MRI patterns of invasive lobular cancer: T1 and T2 features

Purpose

The aim of this study was to describe magnetic resonance imaging (MRI) patterns in 21 patients with histologically proven invasive lobular cancer (ILC) of the breast.

Materials and methods

We retrospectively reviewed MR images of 21 out of 24 women with ILC of the breast. Three women were excluded from the study because they underwent neoadjuvant chemotherapy after MRI. Thirteen of the 24 women had positive clinical findings. All 24 patients underwent mammography, sonography and MRI. MRI was performed to evaluate disease extent and multifocality/multicentricity before modified radical mastectomy (n=5) or quadrantectomy (n=16). Two experienced radiologists reviewed the MRI scans and described the tumour patterns.

Results

We identified five morphological patterns of ILC: a solitary mass with irregular margins (n=8); a mass with smooth margins (n=5); multiple small enhancing foci with interconnecting enhancing strands (n=4); dominant lesion surrounded by small foci (n=3); one MR examination was negative.

Conclusions

Architectural and dynamic features are important in the interpretation of breast MRI findings. ILC may be detected on MRI as solitary or multiple lesions that correspond to tumour morphology on pathologic examination. False-negative MRI findings do occur in a small percentage of ILC.     

Prostate cancer: performance characteristics of combined T2W and DW-MRI scoring in the setting of template transperineal re-biopsy using MR-TRUS fusion

Objectives

To measure the performance characteristics of combined T₂-weighted (T₂W) and diffusion-weighted (DW) magnetic resonance imaging (MRI) suspicion scoring prior to MR-transrectal ultrasound (TRUS) fusion template transperineal (TTP) re-biopsy.

Methods

Thirty-nine patients referred for prostate re-biopsy, with prior MRI examinations, were retrospectively included. The MR images, including T₂W and DW-MRI, had been independently evaluated prospectively by two radiologists using a structured scoring system. An MR-TRUS fusion TTP re-biopsy was used for MR target and non-targeted biopsy cores. Targeting performance and correlation with disease status were evaluated on a per-patient and per-region basis.

Results

The cancer yield was 41 % (16/39 patients). MR targeting accurately detected the disease in 12/16 (75 %) cancerous patients and missed the disease in 4/16 (25 %) patients, all with Gleason 3?+?3 disease. There was a significant relationship (P?<?0.01) between MR suspicion score and the significance of cancer. Reader 1 had significantly higher sensitivity in the transition zone (TZ; 0.84) compared with the peripheral zone (PZ; 0.32) (P?=?0.04). Inter-reader agreement was moderate for the PZ and substantial for the TZ.

Conclusions

MRI targeting is beneficial in the setting of TTP MR-TRUS fusion re-biopsy and MR suspicion score relates to prostate cancer clinical significance. A T₂W and DW-MRI structured scoring system results in good inter-reader agreement in this setting.

Key Points

? Pre-biopsy MRI aids the detection of high significance cancer during prostate re-biopsy. ? MRI suspicion level correlates with the clinical significance of prostate cancer detected. ? T ₂ W and DW-MRI structured scoring of pre-biopsy MRI permits good inter-reader agreement.     

Three-Dimensional Rotational Angiography of the Foot in Critical Limb Ischemia: A New Dimension in Revascularization Strategy

Purpose

To evaluate the additional value of three-dimensional rotational angiography (3DRA) of the foot compared with digital subtraction angiography (DSA) in patients with critical limb ischemia (CLI).

Technique

For 3DRA, the C-arm was placed in the propeller position with the foot in an isocentric position. The patient’s unaffected foot was positioned in a footrest outside the field of view. For correct timing of 3DRA, the delay from contrast injection in the popliteal artery at the level of knee joint to complete pedal arterial enhancement was assessed using DSA. With this delay, 3DRA was started after injection of 15 ml contrast. Imaging of the 3DRA could directly be reconstructed and visualized.

Materials and Methods

Patients undergoing 3DRA of the foot were prospectively registered. DSA and 3DRA images were scored separately for arterial patency and presence of collaterals. Treatment strategies were proposed based on DSA with and without the availability of 3DRA.

Results

Eleven patients underwent 3DRA of the foot. One 3DRA was not included because the acquisition was focused on the heel instead of the entire foot. Diagnostic quality of 3DRA was good in all ten patients. 3DRA compared with DSA showed additional patent arteries in six patients, patent plantar arch in three patients, and collaterals between the pedal arteries in five patients. Additional information from 3DRA resulted in a change of treatment strategy in six patients.

Conclusion

3DRA of the foot contains valuable additional real-time information to better guide peripheral vascular interventions in patients with CLI and nonhealing tissue lesions.     

Utility of susceptibility-weighted imaging and arterial spin perfusion imaging in pediatric brain arteriovenous shunting

Introduction

The objectives of the study are to investigate the application of susceptibility-weighted imaging (SWI) and arterial spin labeling (ASL) imaging in the assessment of shunting and the draining veins in pediatric patients with arteriovenous shunting and compare the utility of SWI and ASL with conventional MR and digital subtraction angiography (DSA).

Methods

This study is a retrospective study of 19 pediatric patients with arteriovenous shunting on brain MRI who were also evaluated with DSA. We assessed the ability of conventional MRI sequences, susceptibility magnitude images, phase-filtered SWI images, and pulsed ASL images in the detection of arteriovenous (AV) shunting, number of draining veins and drainage pathways in comparison to DSA.

Results

The mean number of detected draining veins on DSA (3.63) was significantly higher compared to SWI phase-filtered image (mean?=?2.72), susceptibility magnitude image (mean?=?2.92), ASL (mean?=?1.76) and conventional MRI (2.47) (p?p?>?0.05). ASL was the only method that correctly identified superficial and deep venous drainage in all patients. Regarding detection of shunting, ASL, SWI phase-filtered, and magnitude images demonstrated shunting in 100, 83, and 84 % of patients, respectively.

Conclusion

SWI depicts a higher number of draining vein compared to conventional MR pulse sequences. ASL is a sensitive approach in showing 100 % sensitivity in the detection of AV shunting and in the diagnosis of the pattern of venous drainage. The present findings suggest the added utility of both SWI and ASL in the assessment of AV shunting.     

Towards risk stratification in systemic atherosclerosis: value of myocardial function and viability imaging as an adjunct to MR angiography

Objectives

To longitudinally assess the value of cardiac functional and viability imaging as a supplement to MR angiography in patients with atherosclerotic disease.

Methods

Cardiac MRI was performed in 195 consecutive patients with symptomatic peripheral arterial disease. Of these, 186 patients were followed for 22?±?5 months for the presence of cardiac events (cardiac death, acute coronary syndrome and hospitalisation as a result of congestive heart failure).

Results

Myocardial viability imaging showed a high prevalence of known (n?=?31) and occult myocardial infarctions (MI) (n?=?26). Cardiac events occurred more often in patients with reduced ventricular function (ejection fraction (EF) less than 40%, cardiac event in 4/8 patients; EF 40–55%, cardiac event in 10/40 patients; EF greater than 55%, cardiac event in 15/138 patients) as well as in patients with occult MI (8/25 patients) and known MI (11/30 patients). In patients with normal function, the detection of a previous MI was of high relevance to prognosis.

Conclusions

Both reduced EF and the presence of MI influence patients’ prognoses. Performing cardiac MRI in this patient population may influence further patient management including intensified risk factor intervention.     

Postiktale MR-Veränderungen

Background

Postictal MR findings are analyzed in the context of MR morphological differential diagnoses.

Patients and methods

Postictal MRI was performed in 11 patients. The patterns of MR changes and their differential diagnoses were analyzed.

Results

Focal accentuation of signal increase in the cortex was found on T2-weighted images in 90% of these cases, pial enhancement in 70% and signal changes of the pulvinar/thalamus in 40%. The most common differential diagnoses were encephalitis, and in tumor patients carcinomatous involvement of the meninges.

Conclusion

Postictal MR changes vary widely and are difficult to differentiate from illnesses such as encephalitis and carcinomatosis involving the meninges. Nevertheless, knowledge of the typical pattern of postictal MR findings and the clinical course may help to avoid mistaken diagnoses.