Whole-body MRI in patients with Non-bacterial Osteitis: Radiological findings and correlation with clinical data

OBJECTIVES

To correlate clinical findings of Non-bacterial Osteitis (NBO) with whole-body MRI (WB-MRI) findings and determine a radiologic index for NBO (RINBO) which allows standardized reporting of WB-MRI.

METHODS AND MATERIALS

In a prospective study, 40 patients with diagnosis of NBO underwent clinical examination and WB-MRI in which STIR- and T1- weighted images were assessed for NBO-typical lesions. Parameters of interest for RINBO were: number of radiologically active lesions (RAL), size of the patients' maximum RAL presence of extramedullary and spinal involvement. Results were tested for statistical agreement of clinical and MR-based lesion detection. RINBO was tested for correlation with clinical activity.

RESULTS

62/95 clinically/radiologically active lesions were found in 30/33 patients. In 45 % of the cohort, more active lesions were detected by WB-MRI than by clinical examination. RINBO was a significant predictor for the presence of clinically active lesions.

CONCLUSION

WB-MRI is a powerful diagnostic tool for patients with NBO which can reveal asymptomatic disease activity. With RINBO a standardized evaluation approach is proposed which helps assessing radiologic disease burden and predicts clinical disease activity.

KEY POINTS

• Whole body MRI is a powerful diagnostic tool for patients with non-bacterial Osteitis. • Whole body MRI can reveal asymptomatic disease activity. • The radiologic index RINBO offers a standardized evaluation approach.

[Incidental radiological findings]

All findings which arise in the context of radiological diagnostics, potentially affect the health of a subject but with no intention to detect the corresponding finding are considered to be incidental radiological findings (IF). The prevalence of IFs is increasing due to the wider use of modern imaging techniques, such as magnetic resonance imaging (MRI) and computed tomography (CT) in routine clinical practice and the inclusion of imaging, such as whole body MRI in large population-based cohorts. The reporting of radiological IFs can lead to further diagnostics and treatment. The management of IFs in the clinical routine is regulated by the guidelines of the various academic societies. The management of IFs in the setting of research studies differs depending on various factors, such as study design and health status of enrolled subjects. In general, IFs must be disclosed to the subject if the radiological IFs are potentially clinically relevant; however, subjects must also be protected from the consequences of false positive findings. This review article discusses radiological IFs in the setting of the clinical routine and research studies and provides a basic summary of the management recommendations for commonly occurring IFs.

Assessment of the diagnostic value of dual-energy CT and MRI in the detection of iatrogenically induced injuries of anterior cruciate ligament in a porcine model

INTRODUCTION

Magnetic resonance imaging (MRI) is the standard of reference for the non-invasive evaluation of ligament injuries of the knee. The development of dual-energy CT (DE-CT) made it possible to differentiate between tissues of different density by two simultaneous CT measurements with different tube voltages. This approach enables DE-CT to discriminate ligament structures without intra-articular contrast media injection. The aims of this study were on the one hand to determine the delineation of the anterior cruciate ligament (ACL) and on the other hand to assess the diagnostic value of DE-CT and MRI in the detection of iatrogenically induced injury of the ACL in a porcine knee joint model.

MATERIALS AND METHODS

Twenty porcine hind legs, which were placed in a preformed cast in order to achieve a standardized position, were scanned using DE-CT. Thereafter, a 1.5-T MRI using a standard protocol was performed. The imaging procedures were repeated with the same parameters after inducing defined lesions (total or partial incision) on the ACL arthroscopically. After post-processing, two radiologists and two orthopedic surgeons first analyzed the delineation of the ACL and then, using a consensus approach, the iatrogenically induced lesions. The result of the arthrotomy was defined as the standard of reference.

RESULTS

The ACL could be visualized both on DE-CT and MRI in 100% of the cases. As for the MRI, the sensitivity and specificity of detecting the cruciate ligament lesion respectively compared with the defined arthrotomy was 66.7% and 78.6% for intact cruciate ligaments, 100% and 75% in the case of a complete lesion, 33.3% and 78.6% for lesions of the anteromedial bundle, and 0% and 100% for lesions of the posterolateral bundle. In comparison, DE-CT demonstrated a sensitivity and specificity of 66.7% and 71.4% in the case of intact cruciate ligaments, 75% and 68.8% in the case of completely discontinued ACLs, 0% and 92.9% in the case of lesions of the anteromedial bundle, and 25% and 87.5% in the case of lesions of the posterolateral bundle.

CONCLUSIONS

The present ex vivo experiment shows that both study modalities (DE-CT and MRI) are equal with regard to the delineation of the ACL, while MRI achieved higher sensitivity and specificity regarding iatrogenically induced complete ACL lesions. DE-CT could be a possible alternative to MRI for certain indications in the diagnosis of a knee ligament injury.

Whole-body MRI and MRA for evaluation of the prevalence of atherosclerosis in a cohort of subjectively healthy individuals

Objectives

To assess the prevalence of cardiovascular findings in asymptomatic individuals by means of 1.5-T whole-body magnetic resonance imaging and angiography.

Methods

A cohort of 138 individuals (118 men, 20 women) with a mean age of 54 years (SD ± 7.55) was referred to whole-body MRI at 1.5-T, including contrast-enhanced whole-body MR angiography (MRA) and cardiac MRI. A total of 2,065/2,070 vessel segments (99.8%) and cardiac function were evaluated.

Results

Approximately one-fourth of the participating individuals had vascular abnormalities. In 17 subjects (12.3% of all subjects) significant luminal narrowing was observed in at least one vascular segment. Luminal narrowing (mild to severe) was observed in 1 (0.7% of all subjects respectively) of the renal arteries, 7 (5.0%) of the carotid arteries, and 3 (2.2%) of the pelvic and upper leg arteries, and in 17 segments (12.3%) of arteries in the lower leg.

In cardiac function and perfusion imaging, wall motion disorders were observed in six patients (4.3%), with additional delayed enhancement and isolated delayed enhancement present in two cases. Functional parameters differed from reference values in 55 cases.

Conclusions

Even in an asymptomatic cohort of middle-aged predominantly male individuals, atherosclerotic disease is not uncommon and is detectable by whole-body MRI.

Main Messages

In middle-aged predominantly male individuals, atherosclerotic disease is not uncommon.

Even in an asymptomatic collective, approximately one fourth had vascular abnormalities.

Using whole-body MR angiography (MRA), 99.8% of 2,070 vessel segments could be evaluated.

[Challenging the dogma on inferiority of stainless steel implants for fracture fixation. An end of the controversy?]

BACKGROUND

Titanium plates represent the predominant implants of choice for fracture care in Central Europe, based on the apparently favourable properties related to improved "biocompatibility". The present study was designed to test the hypothesis that the use of stainless steel implants for selected fractures represents a safe and efficient treatment modality, which is not associated with an increased rate of complications and surgical revisions.

METHODS

We conducted a retrospective analysis of a prospective database during a 5-year study period (01/01/2006-12/31/2010) at an academic Level 1 Trauma Center on all fractures treated by stainless steel plates. Inclusion criteria consisted of all consecutive patients >15 years of age whose fractures were fixated with a stainless steel plate. All fractures were classified according to the AO/OTA system. Outcome parameters consisted of the rate of complications and surgical revisions, and the data were placed into context with the published complication rates for titanium plates.

RESULTS

A total of 1,001 consecutive patients who underwent surgical fixation of fractures in the indication spectrum of this study were screened. Of these, 751 patients fulfilled the inclusion criteria. These patients had 774 fractures which were fixated with 859 stainless steel plates. Open fractures accounted for 9.6% of all injuries (n=74). The complication rate of the 774 fractures treated with stainless steel plates was 8.01% (n=62), with a surgical revision rate of 5.16% (n=40). These data are below the reported incidence of complications and surgical revisions for titanium plates in the identical indication spectrum in the pertinent literature published.

CONCLUSIONS

The fixation of selected fractures with stainless steel implants represents a safe and efficient treatment option, which does not appear to be associated with increased complication rates. These data challenge the anecdotal superiority of titanium plates and should spur a new discussion on the use of stainless steel implants, particularly under the aspect of cost savings in the DRG era.

[Bariatric surgery and associated complications: radiological imaging]

Obesity is an increasing problem faced by the healthcare system. In managing obesity, bariatric surgery is becoming more important with evidence showing a reduction in long-term morbidity and mortality. There are special challenges faced by the radiology department in providing an imaging service for this population of patients, from technical requirements through to the interpretation of post-surgical images. This article provides an overview of the most frequently performed procedures, normal postoperative imaging findings and the appearance of common complications.

Comparison of a new whole-body continuous-table-movement protocol versus a standard whole-body MR protocol for the assessment of multiple myeloma

OBJECTIVES

To evaluate a whole body (WB) continuous-table-movement (CTM) MR protocol for the assessment of multiple myeloma (MM) in comparison to a step-by-step WB protocol.

METHODS

Eighteen patients with MM were examined at 1.5T using a WB CTM protocol (axial T2-w fs BLADE, T1-w GRE sequence) and a step-by-step WB protocol including coronal/sagittal T1-w SE and STIR sequences as reference. Protocol time was assessed. Image quality, artefacts, liver/spleen assessability, and the ability to depict bone marrow lesions less than or greater than 1 cm as well as diffuse infiltration and soft tissue lesions were rated. Potential changes in the Durie and Salmon Plus stage and the detectability of complications were assessed.

RESULTS

Mean protocol time was 6:38 min (CTM) compared to 24:32 min (standard). Image quality was comparable. Artefacts were more prominent using the CTM protocol (P = 0.0039). Organ assessability was better using the CTM protocol (P < 0.001). Depiction of bone marrow and soft tissue lesions was identical without a staging shift. Vertebral fractures were not detected using the CTM protocol.

CONCLUSIONS

The new protocol allows a higher patient throughput and facilitates the depiction of extramedullary lesions. However, as long as vertebral fractures are not detectable, the protocol cannot be safely used for clinical routine without the acquisition of an additional sagittal sequence.

B-flow and color Doppler sonography findings in iatrogenic carotid-jugular arteriovenous fistula

We describe the case of a 66-year-old woman with an aortic valve reconstruction. Subsequently she presented with an arteriovenous fistula (AVF) between the left common carotid artery and internal jugular vein following several attempts of jugular catheter insertion. Due to aliasing, correct visualization of the fistula track was hindered by conventional color Doppler. However, by using the B-flow imaging technique, the fistula track could be detected without aliasing or overwriting. Duplex examination revealed an AVF between both vessels with an arterialized waveform in the left jugular vein and a high-velocity turbulent flow inside the fistula. Due to these findings we will change our routine scanning protocol for extracranial vessels and will use B-flow in indistinctive or difficult conditions to obtain additional informations.

Three-dimensional pelvimetry by computed tomography

PURPOSE

This study was undertaken to assess the agreement of computed tomography (CT) pelvimetry with different postprocessing techniques.

MATERIALS AND METHODS

CT data sets of 25 patients were retrospectively analysed. There were no CT examinations performed solely for pelvimetry, and there was no radiation exposure for study purposes. Six pelvimetric measurements were obtained by two independent observers in four data sets of each patient, i.e. on biplanar topograms, multiplanar reconstructions of 1-mm slices, volume-rendered images of the same data and volume-rendered images based on 5-mm-thick images. Interobserver agreement and variability were determined by Bland-Altman analysis. A human skeleton was also scanned and measured with the same techniques and by ruler as reference.

RESULTS

With a correlation coefficient of 0.98, interobserver agreement was best for assessing 3D volume-rendered images reconstructed from 1-mm-thick slices. Interobserver variability was very good for sagittal outlet and midpelvic diameter, transverse inlet diameter and obstetric conjugate (correlation coefficients 0.96-0.99) but limited for intertuberous and interspinous distance. CT and ruler measurements of the skeleton showed excellent agreement.

CONCLUSIONS

Pelvimetry can be obtained with low interobserver variability on 3D volume-rendered CT reconstructions. Thus, CT pelvimetry is suitable to gain exact knowledge of pelvic anatomy to identify relevant parameters for dystocia in retrospective studies.

[64-year old patient with tachycardia and signs of heart failure]

We report on a 64-year old patient with known Morbus Osler and high cardiac output failure due to distinct arterio-venous malformations of the liver. Since the patient suffered from severe right heart insufficiency despite optimized medical therapy, we decided to conduct an interventional occlusion of the hepatic shunts in three single sessions. The transient elevation of transaminases was reversible. After interventional therapy cardiac output decreased from 20 l/min to 15 l/min (25%) leading to a reduction of diuretic dosage and a sustained stabilization of the clinical condition.

Mimicking of Cerebral Herniation Through γ-Hydroxybutyric Acid Therapy

Besides being a treatment option for narcolepsy, γ-hydroxybutyrate is used as an adjuvant during anesthesia in Europe. In addition, it is illegally used as a recreational drug. Fixed and dilated, asymmetric pupils developed in 2 patients during continuous therapy with intravenous γ-hydroxybutyrate, which was added to the long-term anesthetics fentanyl and midazolam. Cerebral herniation as an alternative cause for the pupillary changes was ruled out by using continuous intracranial pressure monitoring and computed tomography. In both patients, the pupillary abnormalities resolved after discontinuation of γ-hydroxybutyrate. Thus, fixed and dilated pupils that are asymmetric seem to be an important side effect of γ-hydroxybutyrate therapy that may mimic cerebral herniation in deeply anesthetized patients.

Mimicking of cerebral herniation through gamma-hydroxybutyric acid therapy

Besides being a treatment option for narcolepsy, gamma-hydroxybutyrate is used as an adjuvant during anesthesia in Europe. In addition, it is illegally used as a recreational drug. Fixed and dilated, asymmetric pupils developed in 2 patients during continuous therapy with intravenous gamma-hydroxybutyrate, which was added to the long-term anesthetics fentanyl and midazolam. Cerebral herniation as an alternative cause for the pupillary changes was ruled out by using continuous intracranial pressure monitoring and computed tomography. In both patients, the pupillary abnormalities resolved after discontinuation of gamma-hydroxybutyrate. Thus, fixed and dilated pupils that are asymmetric seem to be an important side effect of gamma-hydroxybutyrate therapy that may mimic cerebral herniation in deeply anesthetized patients.

[Screening in cardiovascular diseases]

Cardiovascular disease still ranks number one in the mortality statistics in the industrialized world. In Germany the five most common causes of death are all associated with arteriosclerotic changes of the arterial vasculature. As the treatment often extends over long periods and it can be impossible for patients to work, peripheral arterial occlusive disease (PAOD) constitutes a not inconsiderable economic factor. Thus, screening for arteriosclerotic disease seems to be reasonable, because the potential for influencing arteriosclerotic changes is known to be higher in an early stage of the disease even before symptoms become apparent. Not every case can be cured, but progression can frequently be slowed down. The need for invasive procedures, some of them associated with ionizing radiation, limited the use of imaging of the arterial vasculature for a long time. Noninvasive clinical examinations such as the "ankle brachial index" (ABI) can indicate the presence of PAOD, though exact localization of the pathologic changes is not possible except with imaging methods. In contrast to these, MRI is a noninvasive imaging modality that does not involve ionizing radiation but offers high spatial resolution arterial imaging.

Multislice computed tomography versus contrast-enhanced ultrasound in evaluation of complex cystic renal masses using the Bosniak classification system

To assess the diagnostic performance of multislice computed tomography (MS-CT) in the classification of atypical or complex cystic renal masses using the Bosniak system in comparison to contrast-enhanced ultrasound (CEUS) and, in unclear cases, to the surgery findings.Thirty-two consecutive patients (14 women, 18 men; age range 39-72 years) with 37 atypical or complex cystic renal masses at MS-CT underwent conventional ultrasound (US) and CEUS. CEUS employed a low-MI technique using 1.6-2.4 ml SonoVue (Bracco, Italy) i.v. and a 2-4 MHz multifrequency transducer (Siemens, Sequoia, Acuson). Fourteen masses were resected, the remaining 23 lesions were followed up for periods ranging from 3 months to 2 years. Images and digital cine clips of all lesions were evaluated by blinded readers. On the basis of MS-CT appearance the lesions were assigned to the Bosniak classification. Similar criteria modified for US imaging were used to score atypical cysts at CEUS. In the Bosniak classification at MS-CT the lesions were scored as category II (n=15), IIF (n=7), III (n=8) and IV (n=7). At CEUS, masses were classified as Bosniak classification II (n=8), IIF (n=12), III (n=8) or IV (n=9). All type IV and 6/8 type III and 1/8 type IIF lesions were removed surgically. All category IV and 3/8 category III lesions of the surgical group were malignant, the one type IIF lesion was benign. All class II and IIF cysts except one were stable after a follow-up period ranging from 3 months to 2 years. In 7/37 lesions (19%) the MS-CT and CEUS scores were different, while in 30/37 (81%) they were equivalent. CEUS depicted more thin septa than MS-CT, or upgraded wall thickness, resulting in a Bosniak score upgrade from category II to IIF in 5 lesions. Two cystic renal masses could not be clearly assigned by MS-CT but were considered malignant due to the additional information from CEUS, which was confirmed by surgical removal (small cystic renal cancer).CEUS with SonoVue allows an early evaluation of atypical or complex cystic renal masses. It is an additional examination to MS-CT. Due to the dynamic examination, additional information about perfusion of the cystic septa or cystic renal cancer can be gained.

Imaging of aortic lesions with color coded duplex sonography and contrast-enhanced ultrasound versus multislice computed tomography (MS-CT) angiography

PURPOSE

The purpose of this study was to compare color coded duplex sonography (CCDS), contrast-enhanced ultrasound (CEUS) and multislice computed tomography (MS-CT) angiography in pathological aortic lesions.

MATERIAL AND METHODS

36 patients with a mean age of 71 years (range 51-87 yrs) with known or suspected treated and untreated aortic lesions detected by CTA were included in this prospective study. Standardized MS-CTA using a 16 or 64 row scanner (Somatom Sensation 16 or 64, Siemens Medical Systems, Forchheim, Germany) served as reference standard. The patients were examined with CCDS and CEUS (Logiq 9, General Electrics, Milwaukee, WI) using the low MI technique with intravenous injection of 1.6-2.4 ml SonoVue (Bracco, Italy). Contrast enhanced ultrasound was performed in the arterial, venous and late venous phase.

RESULTS

In all patients CEUS resulted in a relevant diagnosis of an aortic pathology. In total, two covered ruptures, nine aortic dissections and five aortic aneurysms were detected. In the routine follow-up of 20 patients following endovascular repair (EVAR) of abdominal aortic aneurysm (AAA), one type 3 and three type 2 endoleaks after y-stent graft were detected. For presurgical planning, in addition to the perfused true and false lumen after dissection the perfusion of the renal arteries was examined.

CONCLUSION

CEUS with SonoVue allows the evaluation of aortic lesions. It is an additional examination to CTA. It may allow a more rapid and noninvasive diagnosis, especially in critical patients from intensive care units because of its bedside availability. As the examination is dynamic, additional information about blood flow in the true and false lumen and about renal perfusion after dissections can be evaluated. Especially in patients with contraindications to CT contrast agents (e.g. due to renal failure or severe allergy), CEUS provides a good alternative to MS-CT.