Georg Riegler

Feasibility of texture analysis for the assessment of biochemical changes in meniscal tissue on T1 maps calculated from delayed gadolinium-enhanced magnetic resonance imaging of cartilage data: comparison with conventional relaxation time measurements

Objectives:To (1) establish the feasibility of texture analysis for the in vivo assessment of biochemical changes in meniscal tissue on delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), and (2) compare textural with conventional T1 relaxation time measurements calculated from dGEMRIC data (“T1(Gd) relaxation times”). Materials and Methods:We enrolled 10 asymptomatic volunteers (7 men and 3 women; mean age, 27.2 ± 4.5 years), without a history of meniscus damage, in our study. MRI of the right knee was performed at 3.0 T. An isotropic, 3-dimensional (3D), double-echo steady-state sequences was used for morphologic evaluation, and a dual flip angle 3D gradient echo sequence was used for T1(Gd) mapping. All MRI scans were performed 90 minutes after injection of 0.2 mmol/kg of Gd-diethylenetriamine pentaacetic acid (DTPA)2−, and subsequently, during application of a compressive force (50% of the body weight) in the axial direction. Regions of interest, covering the central portions of the posterior horn of the medial meniscus, were defined on 3 adjacent sagittal sections. Based on the relaxation time maps, mean T1(Gd), as well as the T1(Gd) texture features derived from the co-occurrence matrix (COC: Angular Second Moment, Entropy, Inverse Difference Moment) and wavelet transform (WAV: WavEnLL, WavEnHL, WavEnHH, WavEnLH), were calculated. Paired t tests were used to assess differences between baseline and compression, and intraclass correlation coefficients (ICC) were calculated to establish the intrarater reliability of the measurements. Results:Mean T1(Gd) (−67.3 ms, P = 0.011), Angular Second Moment (−0.0002, P = 0.009), Entropy (+0.033, P = 0.025), WavEnLL (+1011.16, P = 0.002), WavEnHL (+18.64, P = 0.012), and WavEnLH (+72.74, P = 0.035) differed significantly between baseline and compression. Intrarater reliability was substantial for mean T1(Gd) relaxation times (ICC = 0.99–1.0), and also for T1(Gd) co-occurrence matrix (ICC = 0.63–0.92) and WAV (ICC = 0.86–0.98) features. Conclusions:Texture features extracted from T1 maps calculated from dGEMRIC data are feasible for the in vivo assessment of biochemical changes in the menisci, such as might be induced by mechanical loading. Thus, T1(Gd) texture features complement conventional relaxation time measurements. Further studies are necessary to determine whether the mechanical compression, or a prolonged Gd-DTPA2− uptake, or both, are responsible for the observed decrease in mean T1(Gd) relaxation times in the menisci.

Gadolinium diethylenetriaminepentaacetate enhancement kinetics in the menisci of asymptomatic subjects: a first step towards a dedicated dGEMRIC (delayed gadolinium-enhanced MRI of cartilage)-like protocol for biochemical imaging of the menisci

It was our aim to investigate the gadolinium diethylenetriaminepentaacetate (Gd‐DTPA2−) enhancement kinetics in the menisci of the knee joint over a prolonged period of time. Six asymptomatic volunteers (four men and two women; mean age, 25 ± 2.4 years) were enrolled. Sagittal, T1‐weighted, spin‐echo MR sequences of the right knee joint were obtained at 3 T. Imaging was performed before (baseline), 1 h after and in half‐hour intervals up to 9 h after the intravenous administration of 0.2 mmol/kg of Gd‐DTPA2−. To measure the rates of contrast enhancement relative to the baseline, regions of interest that covered the anterior and posterior horns of the medial and lateral meniscus were defined on each of two adjacent sections, and enhancement curves were constructed. An enhancement peak between 2.5 and 4.5 h after Gd‐DTPA2− administration was observed, and analysis of variance also revealed no significant difference (p = 0.94), in terms of enhancement, within this time interval. Pair‐wise, post hoc testing also revealed no significant differences between 2.5 and 3, 3 and 3.5, 3.5 and 4, and 4 and 4.5 h post Gd‐DTPA2− application. Our preliminary data therefore suggest that the time window suitable for a dGEMRIC (delayed gadolinium‐enhanced MRI of cartilage)‐like T1 mapping of the menisci is relatively short, and lies between 2.5 and 4.5 h after Gd‐DTPA2− injection. Copyright

High-Resolution Axonal Bundle (Fascicle) Assessment and Triple-Echo Steady-State T2 Mapping of the Median Nerve at 7 T: Preliminary Experience.

ObjectivesThe aims of this preliminary study were to determine the number of axonal bundles (fascicles) in the median nerve,1 using a high-resolution, proton density (PD)–turbo spin echo (TSE) fat suppression sequence, and to determine normative T2 values, measured by triple-echo steady state, of the median nerve in healthy volunteers and in patients with idiopathic carpal tunnel syndrome (CTS), at 7 T.2 Materials and MethodsThis prospective study was approved by the local ethics committee and conducted between March 2014 and January 2015. All study participants gave written informed consent. Six healthy volunteers (30 ± 12 years) and 5 patients with CTS (44 ± 16 years) were included. Measurements were performed on both wrists in all volunteers and on the affected wrist in patients (3 right, 2 left). Based on 5-point scales, 2 readers assessed image quality (1, very poor; 5, very good) and the presence of artifacts that might have a possible influence on fascicle determination (1, severe artifacts; 5, no artifacts) and counted the number of fascicles independently on the PD-TSE sequences. Furthermore, T2 values by region of interest analysis were assessed. Student t tests, a hierarchic linear model, and intraclass correlation coefficients (ICCs) were used for statistical analysis. ResultsProton density-TSE image quality and artifacts revealed a median of 5 in healthy volunteers and 4 in patients with CTS for both readers. Fascicle count of the median nerve ranged from 13 to 23 in all subjects, with an ICC of 0.87 (95% confidence interval [CI], 0.67–0.95). T2 values were significantly higher (P = 0.023) in patients (24.27 ± 0.97 milliseconds [95% CI, 22.19–26.38]) compared with healthy volunteers (21.01 ± 0.65 milliseconds [95% CI, 19.61–22.41]). The ICC for all T2 values was 0.97 (95% CI, 0.96–0.98). ConclusionsThis study shows the possibility of fascicle determination of the median nerve in healthy volunteers and patients with CTS (although probably less accurately) with high-resolution 7 T magnetic resonance imaging, as well as significantly higher T2 values in patients with CTS, which seems to be associated with pathophysiological nerve changes.

Changes in Cartilage and Tendon Composition of Patients With Type I Diabetes Mellitus: Identification by Quantitative Sodium Magnetic Resonance Imaging at 7 T.

ObjectiveThe aim of this study was to investigate possible biochemical alterations in tendons and cartilage caused by type 1 diabetes mellitus (DM1), using quantitative in vivo 7 T sodium magnetic resonance (MR) imaging. Materials and MethodsThe institutional review board approved this prospective study, and written informed consent was obtained. Eight DM1 patients with no history of knee trauma and 9 healthy age- and weight-matched volunteers were examined at 7 T using dedicated knee coils.All participants underwent morphological and sodium MR imaging. Region-of-interest analysis was performed manually for the non–weight-bearing area of the femoral condyle cartilage and for the patella tendon. Two readers read the image data sets independently, twice, for intrareader and interreader agreement. Normalized mean sodium signal intensity (NMSI) values were compared between patients and volunteers for each reader using analysis of variance. ResultsOn morphological images, cartilage in the non–weight-bearing area and the patellar tendon was intact in all patients. On sodium MR imaging, bivariate analysis of variance showed significantly lower mean NMSI values in the cartilage (P = 0.008) and significantly higher values in the tendons (P = 0.025) of patients compared with those of volunteers. ConclusionOur study showed significantly different NMSI values between DM1 patients and matched volunteers. Differences observed in the cartilage and tendon might be associated with a DM1-related alteration of biochemical composition that occurs before it can be visualized on morphological MR sequences.

Musculoskeletal imaging in preventive medicine

SummaryThe aim is to review the modalities in musculoskeletal imaging with view on the prognostic impact for the patient’s and for social outcome and with view on three major fields of preventive medicine: nutrition and metabolism, sports, and patient education. The added value provided by preventive imaging is (1) to monitor bone health and body composition with a broad spectrum of biomarkers, (2) to detect and quantify variants or abnormalities of nerves, muscles, tendons, bones, and joints with a risk of overuse, rupture, or fracture, and (3) to develop radiology reports from the widely used narrative format to structured text and multimedia datasets. The awareness problem is a term for describing the underreporting and the underdiagnosis of fragility fractures in osteoporosis.ZusammenfassungZiel dieser Arbeit ist die Darstellung der radiologischen Modalitäten in der Muskel-Skelett-Diagnostik im Hinblick auf den prognostischen Impact und das individuelle beziehungsweise soziale Outcome von drei Bereichen der Präventivmedizin: Ernährung und Stoffwechsel, Sport und Patienteninformation. Der Mehrwert einer präventiven Bildgebung liegt in (1) der Diagnostik des Knochenstoffwechsels und der Gewebeanalyse (Body Composition), (2) der Erkennung und Quantifizierung von zur Arthrose, Tendinose, Neuritis oder Osteopathie disponierenden anatomischen Veränderungen sowie (3) der Weiterentwicklung radiologischer Befunde zu strukturiertem Text und Multimedia-Datensätzen. Als Awareness-Problem bezeichnet man die zu geringe Rate falsch-negativer Befunde bei Osteoporose.

Influence of PET reconstruction technique and matrix size on qualitative and quantitative assessment of lung lesions on [18F]-FDG-PET: A prospective study in 37 cancer patients

PURPOSE To evaluate the influence of point spread function (PSF)-based reconstruction and matrix size for PET on (1) lung lesion detection and (2) standardized uptake values (SUV). METHODS This prospective study included oncological patients who underwent [18F]-FDG-PET/CT for staging. PET data were reconstructed with a 2D ordered subset expectation maximization (OSEM) algorithm, and a 2D PSF-based algorithm (TrueX), separately with two matrix sizes (168×168 and 336×336). The four PET reconstructions (TrueX-168; OSEM-168; TrueX-336; and OSEM-336) were read independently by two raters, and PET-positive lung lesions were recorded. Blinded to the PET findings, a third independent rater assessed lung lesions with diameters of >4mm on CT. Subsequently, PET and CT were reviewed side-by side in consensus. Multi-factorial logistic regression analyses and two-way repeated measures analyses of variance (ANOVA) were performed. RESULTS Thirty-seven patients with 206 lung lesions were included. Lesion-based PET sensitivities differed significantly between reconstruction algorithms (P<0.001) and between reconstruction matrices (P=0.022). Sensitivities were 94.2% and 88.3% for TrueX-336; 88.3% and 85.9% for TrueX-168; 67.8% and 66.3% for OSEM-336; and 67.0% and 67.9% for OSEM-168; for rater 1 and rater 2, respectively. SUVmax and SUVmean were significantly higher for images reconstructed with 336×336 matrices than for those reconstructed with 168×168 matrices (P<0.001). CONCLUSION Our results demonstrate that PSF-based PET reconstruction, and, to a lesser degree, higher matrix size, improve detection of metabolically active lung lesions. However, PSF-based PET reconstructions and larger matrix sizes lead to higher SUVs, which may be a concern when PET data from different institutions are compared.

High-Resolution Ultrasound Visualization of Pacinian Corpuscles

The aim of this study was to evaluate the possibility of visualizing Pacinian corpuscles in the palm of the hand with high-resolution ultrasound (HRUS). In this prospective study, HRUS with a high-frequency probe (22 MHz) was used. The palms of two fresh cadaveric hands were screened for potential Pacinian corpuscles. Still ultrasound images and dynamic video sequences were obtained. In five regions with large amounts of suspected Pacinian corpuscles, tissue blocks were excised and histologically processed, and corresponding slices were compared with ultrasound images. Further, the transverse diameters of five Pacinian corpuscles, at the level of the metacarpal heads in the palm, were assessed on both sides (in total 100) in healthy volunteers. On ultrasound, Pacinian corpuscles presented as echolucent dots in the subcutis, adjacent to digital nerves and vessels and located 2-3 mm beneath the surface. On histologic sections, these echolucent dots corresponded to Pacinian corpuscles with respect to their position and topographic relationships. The mean transverse diameter for all volunteers was 1.40 ± 0.23 mm (range: 0.8-2.2 mm). This study confirms the ability to reliably visualize Pacinian corpuscles with HRUS, which contributes to our basic understanding of ultrasonographically visible subcutaneous structures and may enhance the diagnosis of pathologies related to Pacinian corpuscles.

Novel Demonstration of the Anterior Femoral Cutaneous Nerves using Ultrasound

PURPOSE  Neuropathy of the intermediate (IFCN) and medial femoral cutaneous nerve (MFCN) is a potential iatrogenic complication of thigh surgery and its diagnosis is limited. This study aimed to evaluate the possibility of the visualization and diagnostic assessment of the IFCN and MFCN with high-resolution ultrasound (HRUS). MATERIALS AND METHODS  In this study, HRUS with high-frequency probes (15 - 22MHz) was used to locate the IFCN and the MFCN in 16 fresh cadaveric lower limbs. The correct identification of the nerves was verified by ink-marking and consecutive dissections at sites correlating to nerve positions (R1 - 3), namely, the origin, the mid portion, and the distal portion, respectively. 12 cases with suspected IFCN and MFCN lesions referred to our clinic for HRUS examinations were also assessed. RESULTS  Anatomical dissection confirmed the correct identification of the IFCN in 16/16 branches at all of the different locations (100 %). MFCN was correctly identified at R1 + 3, in all cases (16/16; 100 %), and in 14/16 cases (88 %) at (R2). 12 cases of patients with IFCN and MFCN pathologies (all of iatrogenic origin) were identified. 9 instances of structural damage were visible on HRUS, and all pathologies were confirmed by almost complete resolution of symptoms after selective HRUS-guided blocks with 0.5 - 1 ml lidocaine 2 %. CONCLUSION  This study confirms that the IFCN and the MFCN can be reliably visualized with HRUS throughout the course of these nerves, both in anatomical specimens and in patients.

A Rare Case of Guyon's Canal Syndrome Caused by Cystic Adventitia Degeneration: High-Resolution Ultrasound Findings

Entrapment of the ulnar nerve inside the ulnar tunnel, which is also called Guyon’s canal, is a well-known entity leading to pain, numbness and loss of function in the part of the hand supplied by the ulnar nerve. Space-occupying lesions in this area, such as ganglions, tendinitis, fracture, arthritis, nonspecific edema and thromboangitis, may cause the entrapment of the nerve, known as ulnar tunnel syndrome. Cystic adventitial disease (CAD) is a rare benign vascular lesion, where cysts form in the adventitia of a blood vessel, first described in the iliac artery (Atkins HJ, Key JA. Br J Surg 1947; 34: 426). CADmay cause local pain due to the stenosis and occlusion of the vessel and can be treated either with USor CT-guided percutaneous cyst aspiration or surgery (Drac P et al. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2011; 155: 309 – 321). For unknown reasons, most of the CAD cases reported thus far involve the popliteal artery in young middle-aged men (Drac P et al. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2011; 155:309 – 321). A few cases have also been described in the external iliac, common femoral, axillary, distal brachial, and radial arteries. Although the pathomechanisms of CAD remain controversial, a theory of joint-related origin has been suggested, similar to the pathogenesis of intraneural ganglion cysts (Spinner RJ et al. Clin Anat 2013; 26: 267 – 281). The diagnosis can be established with high-resolution ultrasound and MRA as the first-choice imaging methods (Drac P et al. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2011; 155: 309 – 321). We report here a unique case of cystic adventitial degeneration that affected the ulnar artery and caused ulnar nerve palsy, which was detected with high-resolution ultrasound. Case Presentation

Brachial plexus ultrasound in a patient with myelodysplastic syndrome and myelosarcoma

although his diaphragm achieved normal parameters, it was smaller than the premorbid size. Thus a “normal” diaphragm thickness and thickening ratio may still be associated with incomplete functional recovery. We recommend that diaphragm ultrasound remain complementary to PFT and clinical data in monitoring recovery. Our case emphasizes that absence of recovery at 12 months does not predict failure of recovery by 3 years. We recommend a cautious approach to surgical interventions during the period of potential recovery. Serial studies of NA, including serial diaphragm ultrasounds, are required to identify predictors of prognosis to guide treatment and management. Dr. Bucelli receives a recurring financial gift from a patient’s family for Parsonage-Turner syndrome research. Ethical Publication Statement: We confirm that we have read the Journal’s position on issues involved in ethical publication and affirm that this report is consistent with those guidelines.