Michaela Plaikner

High resolution ultrasound in posterior interosseous nerve syndrome

Introduction: Posterior interosseous nerve (PIN) syndrome is a rare compression neuropathy of the PIN in the region of the supinator muscle, most common by the arcade of Frohse. We aimed to specify ultrasonographic findings in patients with PIN syndrome in comparison to healthy volunteers. Methods: Ultrasound images and clinical data of 13 patients with PIN syndrome confirmed by neurological examination and electrophysiological testing were evaluated retrospectively. Anteroposterior nerve diameters measured at the arcade of Frohse were compared with those of 20 healthy volunteers. The echotexture and the presence of a caliber change of the PIN were additionally assessed. Results: Enlargement of the PIN was seen in all patients with PIN syndrome, but not in volunteers (statistically significant difference in mean diameter P < 0.05). Furthermore, edema and caliber change of the PIN were present in all patients. Conclusions: High‐resolution ultrasound allows for differentiation between patients with PIN syndrome and healthy volunteers. Muscle Nerve 49: 35–39, 2014

Triple hourglass-like fascicular constriction of the posterior interosseous nerve: a rare cause of PIN syndrome

Abstract Supinator syndrome or posterior interosseous nerve (PIN) syndrome is a compression neuropathy of the deep branch of the radial nerve in the region of the Arcade of Frohse. An extremely rare cause of an acute onset supinator syndrome is the hourglass-like fascicular constriction of the posterior interosseous nerve due to torsion. To our knowledge, only a limited number of cases which describe the sonographic appearance of fascicular torsions are known in the literature. We present a rare case of a supinator syndrome associated with hourglass-like constrictions of the PIN diagnosed by means of sonography.

Upper Extremity Nerves

The major nerves of the upper extremity include the axillary nerve, the musculocutaneous nerve, the medial brachial cutaneous nerve, the medial antebrachial cutaneous nerve, the radial nerve, the ulnar nerve, and the median nerve. A basic knowledge of regional anatomy and topography of these nerves and their major branches is an essential prerequisite for sonographic examinations. By means of landmarks the respective nerve can be easily localized in specific sections of its course. In addition, certain locations exist, where these nerves traverse through narrow tunnels or along bony ridges (such as the carpal tunnel, the ulnar sulcus, or the radial groove). These regions are especially prone for nerve compression or injury and have distinct anatomical features, which must be known to constantly achieve high-quality sonographic diagnoses.

Prediction of the presence of renal artery stenosis by calcium scoring of the abdominal aorta.

OBJECTIVE To establish a method for estimating the probability of renal artery stenosis (RAS) based on the calcium volume score of the aorta (ACS). MATERIALS AND METHODS In a retrospective observation study, CT angiographies acquired on a 64-slice MDCT scanner were analyzed for 1351 patients (female: 531; male 826; mean age 60.9 ± 17.7 years). A volumetric scoring method was used, detecting plaques with a density of more than 600 HU. RESULTS 13.8% of the patients showed a stenosis >50%, 4.1% a stenosis >70%. The ACS was 0.61 ± 1.01 ml calcium. The sensitivity for detection of RAS >50% and RAS >80% was 0.9572 and 1.0, respectively. The negative predictive value (NPV) of a lack of calcification for excluding RAS >50% and RAS >80% was 0.9752 and 1, respectively. As ACS increased, the specificity for RAS >50% increased to 0.9390. With an ACS of 0.380 ml, accuracy reached a maximum of 0.6585. ROC analyses yielded an area under the curve of 0.88 (p<0.0001). Sensitivity, specificity, NPV and PPV are indicated in relation to the degree of RAS, as well as the diagnostic yield of the method, which is valuable in patients older than 50 years. CONCLUSION Due to its extremely high sensitivity and NPV, the ACS is a very useful screening method for RAS. The validity of the method, as well as its diagnostic value is equivalent to that of coronary artery calcium scoring. Lack of calcifications of the aorta renders atherosclerotic RAS highly improbable.

R2*-relaxometry of the pancreas in patients with human hemochromatosis protein associated hereditary hemochromatosis

PURPOSE To evaluate pancreatic iron in patients with human hemochromatosis protein associated hereditary hemochromatosis (HHC) using R2* relaxometry. MATERIALS AND METHODS 81 patients (58 male, 23 female; median age 49.5, range 10-81 years) with HHC were retrospectively studied. All underwent 1.5T magnetic resonance imaging (MRI) of the abdomen. A fat-saturated multi-gradient echo sequence with 12 echoes (TR=200ms; TE-initial 0.99ms; Delta-TE 1.41ms; 12 echoes; flip-angle: 20°) was used for the R2* quantification of the liver and the pancreas. Parameter maps were analyzed using regions of interest (3 in the liver and 2 in the pancreas) and R2* values were correlated. RESULTS 59/81 patients had a liver R2*≥70 1/s of which 10/59 patients had a pancreas R2*≥50 1/s. No patient presented with a liver R2*<70 1/s and pancreas R2*≥50 1/s. All patients with pancreas R2* values≥50 1/s had liver R2* values≥70 1/s. ROC analysis resulted in a threshold of 209.4 1/s for liver R2* values to identify HFE positive patients with pancreas R2* values≥50 1/s with a median specificity of 78.87% and a median sensitivity of 90%. CONCLUSION In patients with HHC R2* relaxometry of the pancreas should be performed when liver iron overload is present and can be omitted in cases with no sign of hepatic iron.

Ultrasound-guided Injections in the Spine

Injection therapies play a major role in the treatment of back pain and radiculopathy and are becoming integral parts of a multidisciplinary approach in treatment and rehabilitation of pain patients. Pararadicular and facet-joint injections in the spine are preferentially performed under computed tomography or fluoroscopy guidance. In this article we present alternative, simple, and easy to learn step by step ultrasound-guided techniques for injection therapies in the cervical and lumbar spine.

CAIPIRINHA-Dixon-TWIST (CDT)-VIBE MR imaging of the liver at 3.0T with gadoxetate disodium: a solution for transient arterial-phase respiratory motion-related artifacts?

PurposeTo determine whether CAIPIRINHA-Dixon-TWIST (CDT) volume-interpolated breath-hold examination (VIBE) improves image quality by reducing gadoxetate-disodium-associated transient arterial-phase motion artefacts in magnetic resonance imaging (MRI) of the liver.Materials and methodsMRI studies of the liver from 270 patients who had received gadoxetate disodium were retrospectively evaluated in regard to arterial timing accuracy and arterial phase motion artefact severity (VIBE: 90/270, CAIPIRINHA-VIBE: 90/270 and CDT-VIBE: 90/270 cases). Three independent and blinded readers assessed arterial phase timing and motion artefact severity (5-point scale). Interrater agreement was calculated by weighted kappa. Continuous variables were compared via a two-sided ANOVA, categorical variables via a χ2 test. An ordinal regression analysis was performed to identify other predictors of motion artefacts.ResultsCDT-VIBE improved correct late arterial timing rates and reduced motion-related image deterioration rates. Successful late arterial liver visualisation was achieved in 56.7% (VIBE) compared with 66.7% (CAIPIRINHA-VIBE) and 84.4% (CDT-VIBE) (P < 0.0001). Good/excellent image quality was achieved in 56.7% vs. 66.7% and 73.3%, respectively (P = 0.03). Male sex negatively influenced image quality (P = 0.03).ConclusionCDT-VIBE increases the diagnostic utility of gadoxetate disodium-based liver MRI by reducing respiratory motion artefacts and optimising late arterial visualisation compared with VIBE and CAIPIRINHA-VIBE.Key Points• CAIPIRINHA-Dixon-TWIST-VIBE-MRI (CDT) mitigates effects of acute transient dyspnoea caused by gadoxetate disodium.• CDT improves late arterial imaging compared with VIBE and CAIPIRINHA-VIBE.• The rate of ideal late arterial images is higher with CDT-VIBE vs. VIBE or CAIPI-VIBE.• The impact of respiratory motion artefacts on arterial phase images can be reduced.

Does gadoxetate disodium affect MRE measurements in the delayed hepatobiliary phase

ObjectivesTo assess if the administration of gadoxetate disodium (Gd-EOB-DTPA) significantly affects hepatic magnetic resonance elastography (MRE) measurements in the delayed hepatobiliary phase (DHBP).MethodsA total of 47 patients (15 females, 32 males; age range 23–78 years, mean 54.28 years) were assigned to standard hepatic magnetic resonance imaging (MRI) with application of Gd-EOB-DTPA and hepatic MRE. MRE was performed before injection of Gd-EOB-DTPA and after 40–50 min in the DHBP. Liver stiffness values were obtained before and after contrast media application and differences between pre- and post-Gd-EOB-DTPA values were evaluated using a Bland-Altman plot and the Mann-Whitney-Wilcoxon test. In addition, the data were compared with regard to the resulting fibrosis classification.ResultsMean hepatic stiffness for pre-Gd-EOB-DTPA measurements was 4.01 kPa and post-Gd-EOB-DTPA measurements yielded 3.95 kPa. We found a highly significant individual correlation between pre- and post-Gd-EOB-DTPA stiffness values (Pearson correlation coefficient of r = 0.95 (p < 0.001) with no significant difference between the two measurements (p =0.49)). Bland-Altman plot did not show a systematic effect for the difference between pre- and post-stiffness measurements (mean difference: 0.06 kPa, SD 0.81). Regarding the classification of fibrosis stages, the overall agreement was 87.23% and the intraclass correlation coefficient was 96.4%, indicating excellent agreement.ConclusionsAdministration of Gd-EOB-DTPA does not significantly influence MRE stiffness measurements of the liver in the DHBP. Therefore, MRE can be performed in the DHBP.Key Points• MRE of the liver can reliably be performed in the delayed hepatobiliary phase.• Gd-EOB-DTPA does not significantly influence MRE stiffness measurements of the liver.• MRE performed in the delayed hepatobiliary-phase is reasonable in patients with reduced liver function.

Pathological fracture of the patella due to an atypical located aneurysmal bone cyst: verification by means of ultrasound-guided biopsy

IntroductionWe report on a rare case of an atypical located aneurysmal bone cyst (ABC) in the patella presenting with pathological fracture after trauma.Materials and methodsUsing all available diagnostic modalities and by means of ultrasound-guided core-needle biopsy an unclear and suspected pathological fractured cystic bone lesion in the patella of a young man could be further clarified.ResultsThe acquired images suggested the diagnosis of a pathological fractured aneurysmal bone cyst after mild trauma. However, due to the extraordinary location and clinical presentation the diagnosis was secured by means of ultrasound-guided biopsy through a small cortical gap.ConclusionAs shown in this rare case of an atypical aneurysmal bone cyst of the patella, the quite seldom but sometimes possible ultrasound-guided biopsy of intraosseous lesions can help to achieve the diagnostic clarification and should also be taken into account as a non-standard procedure.

Is Duplex-Ultrasound a useful tool in defining rejection episodes in composite tissue allograft transplants?

Immunologic reactions in transplanted organs are in more or less all allograft patients detectable: clear parameters exist as e.g. in renal transplants where the clearance power reduces by rejection. On the contrary, in composite tissue allografts clear and objective indicators stating a rejection episode lack. We present the case of a hand-transplanted subject with signs of acute transplant rejection diagnosed by means of Duplex Ultrasound and confirmed by biopsy.