Radial Reconstructions Research Articles

Improved diagnostic accuracy for ulnar-sided TFCC lesions with radial reformation of 3D sequences in wrist MR arthrography

ObjectivesTriangular fibrocartilage complex (TFCC) injuries frequently cause ulnar-sided wrist pain and can induce distal radioulnar joint instability. With its complex three-dimensional structure, diagnosis of TFCC lesions remains a challenging task even in MR arthrograms. The aim of this study was to assess the added diagnostic value of radial reformatting of isotropic 3D MRI datasets compared to standard planes after direct arthrography of the wrist.MethodsNinety-three patients underwent wrist MRI after fluoroscopy-guided multi-compartment arthrography. Two radiologists collectively analyzed two datasets of each MR arthrogram for TFCC injuries, with one set containing standard reconstructions of a 3D thin-slice sequence in axial, coronal and sagittal orientation, while the other set comprised an additional radial plane view with the rotating center positioned at the ulnar styloid. Surgical reports (whenever available) or radiological reports combined with clinical follow-up served as a standard of reference. In addition, diagnostic confidence and assessability of the central disc and ulnar-sided insertions were subjectively evaluated.ResultsInjuries of the articular disc, styloid and foveal ulnar attachment were present in 20 (23.7%), 10 (10.8%) and 9 (9.7%) patients. Additional radial planes increased diagnostic accuracy for lesions of the styloid (0.83 vs. 0.90; p = 0.016) and foveal (0.86 vs. 0.94; p = 0.039) insertion, whereas no improvement was identified for alterations of the central cartilage disc. Readers’ confidence (p < 0.001) and assessability of the ulnar-sided insertions (p < 0.001) were superior with ancillary radial reformatting.ConclusionsAccess to the radial plane view of isotropic 3D sequences in MR arthrography improves diagnostic accuracy and confidence for ulnar-sided TFCC lesions.Key Points• In multi-compartment arthrography of the wrist, ancillary radial plane view aids assessability of the foveal and styloid ulnar-sided insertions of the triangular fibrocartilage complex.• Assessment of peripheral TFCC injuries is more accurate with access to radial multiplanar reconstructions.• Additional radial planes provide greater diagnostic confidence.

Fetal Flow Quantification in Great Vessels Using Motion-Corrected Radial Phase Contrast MRI: Comparison With Cartesian.

Phase contrast MRI in the great vessels is a potential clinical tool for managing fetal pathologies. One challenge is the uncontrollable fetal motion, potentially corrupting flow quantifications. To demonstrate improvements in fetal blood flow quantification in great vessels using retrospectively motion-corrected golden-angle radial phase contrast MRI relative to Cartesian phase contrast MRI. Method comparison. Computer simulation. Seventeen pregnant volunteers. 1.5T and 3T. Cartesian and golden-angle radial phase contrast MRI. Through computer simulations, radial (with and without retrospective motion correction) and Cartesian phase contrast MRI were compared using flow deviations. in vivo Cartesian and radial phase contrast MRI measurements and reconstruction qualities were compared in pregnancies. Cartesian data were reconstructed into gated reconstructions (CINEs) after cardiac gating with metric optimized gating (MOG). For radial data, real-time reconstructions were performed for motion correction and MOG followed by CINE reconstructions. Wilcoxon signed-rank test. Linear regression. Bland-Altman plots. Student's t-test. Simulations showed significant improvements (P < 0.05) in flow accuracy and reconstruction quality with motion correction ([mean/peak] flow errors with ±5 mm motion corruption: Cartesian [35 ± 1/115 ± 7] mL/s, motion uncorrected radial [25 ± 1/75 ± 2] mL/s and motion-corrected radial [1.0 ± 0.5/-5 ± 1] mL/s). in vivo Cartesian reconstructions without motion correction had lower quality than the motion-corrected radial reconstructions (P < 0.05). Across all fetal mean flow measurements, the bias [limits of agreement] between the two measurements were -0.2 [-76, 75] mL/min/kg, while the linear regression coefficients were (Mradial = 0.81 × MCartesian + 29.8 [mL/min/kg], r2 = 0.67). The corresponding measures for the peak fetal flows were -23 [-214, 167] mL/min/kg and (Pradial = 0.95 × PCartesian -1.2 [mL/min/kg], r2 = 0.80). Cartesian reconstructions of low quality showed significantly higher estimated mean and peak (P < 0.05) flows than the corresponding radial reconstructions. Simulations showed that radial phase contrast MRI with motion compensation improved flow accuracy. For fetal measurements, motion-corrected radial reconstructions showed better image quality than, and different flow values from, Cartesian reconstructions. Level of Evidence 1. Technical Efficacy Stage 1. J. MAGN. RESON. IMAGING 2021;53:540-551.

The importance of radial multiplanar reconstructions for assessment of triangular fibrocartilage complex injury in CT arthrography of the wrist

BackgroundTriangular fibrocartilage complex (TFCC) lesions commonly cause ulnar-sided wrist pain and instability of the distal radioulnar joint. Due to its triangular shape, discontinuity of the TFCC is oftentimes difficult to visualize in radiological standard planes. Radial multiplanar reconstructions (MPR) may have the potential to simplify diagnosis in CT wrist arthrography. The objective of this study was to assess diagnostic advantages provided by radial MPR over standard planes for TFCC lesions in CT arthrography.MethodsOne hundred six patients (49 women, 57 men; mean age 44.2 ± 15.8 years) underwent CT imaging after wrist arthrography. Two radiologists (R1, R2) retrospectively analyzed three randomized datasets for each CT arthrography. One set contained axial, coronal and sagittal planes (MPRStandard), while the other two included an additional radial reconstruction with the rotating center either atop the ulnar styloid (MPRStyloid) or in the ulnar fovea (MPRFovea). Readers evaluated TFCC differentiability and condition. Suspected lesions were categorized using Palmer’s and Atzei’s classification and diagnostic confidence was stated on a five-point Likert scale.ResultsCompared to standard planes, differentiability of the superficial and deep TFCC layer was superior in radial reconstructions (R1/R2; MPRFovea: p < 0.001; MPRStyloid: p ≤ 0.007). Palmer and Atzei lesions were present in 86.8% (92/106) and 52.8% (56/106) of patients, respectively. Specificity, sensitivity and accuracy for central Palmer lesions did not differ in radial and standard MPR. For peripheral Atzei lesions, sensitivity (MPRStandard 78.6%/80.4%, MPRStyloid 94.6%/94.6%, MPRFovea 91.1%/89.3%) and accuracy (MPRStandard 86.8%/86.8%, MPRStyloid 96.2%/96.2%, MPRFovea 94.3%/93.4%) improved with additional styloid-centered (p = 0.004/0.008) and fovea-centered (p = 0.039/0.125) reconstructions. No substantial difference was observed between both radial MPR (p = 0.688/0.250). Interrater agreement was almost perfect for each dataset (κStandard = 0.876, κStyloid = 0.894, κFovea = 0.949). Diagnostic confidence increased with addition of either radial MPR (p < 0.001).ConclusionsAncillary radial planes improve accuracy and diagnostic confidence for detection of peripheral TFCC lesions in CT arthrography of the wrist.

Diagnostic Accuracy of Magnetic Resonance Arthrography in Detecting Intra-articular Pathology Associated with Femoroacetabular Impingement.

Purpose The aim of this study was to assess the diagnostic accuracy of magnetic resonance arthrography (MRA) in the detection of intra-articular lesions of the hip in patients affected by femoroacetabular impingement (FAI) by using arthroscopy as reference standard. Methods Twenty-nine consecutive hip arthroscopies performed in 24 patients were considered for the study. Patients had a mean age of 38.3 years. Ultrasound-guided 1.5-T MRA was performed with precontrast short tau inversion recovery, T1-weighted and PD coronal, T1-weighted, and T2-weighted axial with 3-mm-thick slice sequences, and postcontrast T1-weighted fat saturation MRA (Fat-SAT) axial, coronal and oblique sagittal, and T1-weighted Vibe 3D coronal sequences with MPR sagittal, axial, and radial reconstructions with 2-mm-thick slice and coronal density protonil (DP) Fat-SAT. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRA were evaluated by comparison arthroscopy for the following intra-articular findings: acetabular and femoral chondral lesions, labral degeneration, labral tears, synovitis, ligamentum teres (LT) tears, CAM lesions, pincer lesions, loose bodies, and osteophytes. Results An absolute per cent agreement (100%) was observed for all the variables in the assessment of CAM lesions. Sensitivity, specificity, PPV, and NPV of MRA were 100, 68.4, 72.7, and 100%, respectively, for acetabular chondral lesions; 100, 50, 47.3, and 100%, respectively, for femoral chondral lesions; 33, 85, 20, and 91.6%, respectively, for labral tears; 95, 71, 91.3, and 83.3%, respectively, for labral degeneration; 100, 88, 57.1, and 100%, respectively, for LT tears; 33.3, 85, 50, and 73.9%, respectively, for pincer lesions; 50, 96, 66.6, and 92.3%, respectively, for intra-articular loose bodies; and 100, 73.9, 50, and 100%, respectively, for osteophytes. Conclusion MRA may play an important role in detecting intra-articular lesions associated with FAI. This might be helpful for the preoperative planning before hip arthroscopy. Level of Evidence This is a Level 2, diagnostic accuracy study compared with gold standard.

Accuracy in local staging of prostate cancer by adding a three-dimensional T2-weighted sequence with radial reconstructions in magnetic resonance imaging.

BackgroundThe evidence supporting the use of magnetic resonance imaging (MRI) in prostate cancer detection has been established, but its accuracy in local staging is questioned.PurposeTo investigate the additional value of multi-planar radial reconstructions of a three-dimensional (3D) T2-weighted (T2W) MRI sequence, intercepting the prostate capsule perpendicularly, for improving local staging of prostate cancer.Material and MethodsPreoperative, bi-parametric prostate MRI examinations in 94 patients operated between June 2014 and January 2015 where retrospectively reviewed by two experienced abdominal radiologists. Each patient was presented in two separate sets including diffusion-weighted imaging, without and with the 3D T2W set that included radial reconstructions. Each set was read at least two months apart. Extraprostatic tumor extension (EPE) was assessed according to a 5-point grading scale. Sensitivity and specificity for EPE was calculated and presented as receiver operating characteristics (ROC) with area under the curve (AUC), using histology from whole-mount prostate specimen as gold standard. Inter-rater agreement was calculated for the two different reading modes using Cohen’s kappa.ResultsThe AUC for detection of EPE for Readers 1 and 2 in the two-dimensional (2D) set was 0.70 and 0.68, respectively, and for the 2D + 3D set 0.62 and 0.65, respectively. Inter-rater agreement (Reader 1 vs. Reader 2) on EPE using Cohen’s kappa for the 2D and 2D + 3D set, respectively, was 0.42 and 0.17 (i.e. moderate and poor agreement, respectively).ConclusionThe addition of 3D T2W MRI with radial reconstructions did not improve local staging in prostate cancer.

Aortic Pulse Wave Velocities Using Real-Time Phase-Contrast MRI

Purpose: To evaluate aortic pulse wave velocities obtained by real-time phase-contrast (PC) MRI in comparison to cine PC MRI. Methods: Real-time PC MRI of eight healthy volunteers employed highly undersampled radial FLASH sequences and phase-sensitive image reconstructions by regularized nonlinear inversion (NLINV) at 40 ms temporal resolution and 1.3 mm in-plane resolution. Pulse wave velocities were analyzed for combinations of 2, 3 and 4 locations of aortic flow using time-to-upslope and cross-correlation methods. Results: For the time-to-upslope analysis mean pulse wave velocities ranged from 3.5 to 3.9 m s-1 for real-time PC MRI and from 3.5 to 3.8 m s-1 for cine PC MRI. A cross-correlation analysis of the same data resulted in 2.9 to 3.3 m s-1 and 3.3 to 3.7 m s-1, respectively. Conclusion: Real-time PC MRI determined aortic pulse wave velocities from single cardiac cycles in close correspondence to values obtained by cine PC MRI.

Multislice Computed Tomography in the Diagnosis of Superior Canal Dehiscence

Multi-slice computed tomography (MSCT) overestimates the size of superior semicircular canal dehiscences (SSCDs) and also can misinterpret thin bone over the superior semicircular canal as dehiscent. A threshold of the radiodensity of the bone over the superior semicircular canal may exist that could optimize prediction of an actual SSCD. The gold standard for diagnosis of SSCD is MSCT, but there is a higher prevalence of SSCD based on MSCT compared with histologic studies. Overestimation of SSCD can lead to inappropriate diagnosis and treatment. We correlated radiographic and surgical findings in SSCD to determine if MSCT overestimated the size of SSCD and if a threshold radiodensity could be defined, below which actual dehiscence could best be predicted. Participants were 34 humans with SSCD confirmed at surgery. MSCT scans were acquired axially with 0.5-mm collimation and a small field of view (24 cm). Dehiscence sizes measured from radial reconstructions were compared with measurements made during surgery. There were significant differences between radiographic and actual length and width, indicating that MSCT tends to overestimate the size of SSCD. Receiver operating characteristic analysis found a threshold in Hounsfield units that optimized the prediction of dehiscence. Computed tomographic imaging alone can be misleading for diagnosis of SSCD. It can overestimate the size of the dehiscence, and it can falsely detect dehiscences. Clinical symptoms and other signs must be clearly indicative before surgery, and MSCT cannot be used exclusively for the diagnosis of SSCD.

Stellenwert radiärer Reformatierungen in der CT-Diagnostik der Lungenarterienembolie

To evaluate the diagnostic value of radial reformatting of axial multislice CT (MS-CT) data sets in the presumptive diagnosis of pulmonary embolism. In 126 cases with the presumptive diagnosis of an acute pulmonary embolism, 4- and 8-slice axial MS-CT data sets were radially reformatted. The pulmonary vessels were evaluated by five experienced radiologists who determined the number of thrombi at the level of the segmental and subsegmental arteries. A pulmonary artery was considered as thrombosed if it showed at least one unambiguous filling defect on two consecutive sections. It was determined whether the artery was uniformly opacified without filling defects, contained thrombotic material or was completely occluded by a blood clot. Pulmonary vessels that could not be evaluated because of moving artifacts or inadequate opacification were classified as negative. Finally, all experts gave a subjective estimate concerning the simplicity of the diagnosis for both reconstructions. The diagnosis of thromboembolism at a subsegmental level was significantly different for axial sections and radial reconstruction: at 4-slice CT, 77 subsegmental thromboembolisms were found in axial sections vs. 98.6 in radial reconstructions; at 8-slice CT, 23.6 in axial sections vs. 31.2 in radial reconstructions; and using the combined evaluation, 103.2 in axial sections vs. 130.6 in radial reconstructions, with a significance of p = 0.043. The five judges did not find any significant differences in the number of the blood clots in each pulmonary segment. Concerning the simplicity of the diagnosis, the subjective judgment classified the radial reconstructions as better in 49.7 % and the axial sections as better in 22 %. The radial reconstructions of the 4-slice CT were classified as better in 45.7 % vs. 25 % and the 8-slice CT as better in 66 % vs. 16 %. Using radial multiplanar reformatting of the MS-CT data sets improves significantly the recognition of subsegmental pulmonary embolism.

Magnetic resonance arthrography of the acetabular labrum: value of radial reconstructions.

The intention was to compare the sensitivity and specificity of radial planes with oblique coronal and oblique axial planes for the detection of labral abnormalities of the acetabulum on magnetic resonance arthrography (MRa). Twenty cadaveric hip joints were examined by radiography and MRa. For MRa, 15 ml of a solution of iodinated contrast material and gadolinium diethylene triamine tetra-acetic acid (Gd-DTPA; 100:1) were injected under fluoroscopic guidance. MRI was performed on a 1.5-T MR scanner with a fat-suppressed 3D-FLASH sequence (TR/TE/flip-angle 42 ms/10 ms/40 degrees; field of view 16 cm, matrix 256 x 256, section thickness 1.5 mm, pixel size 0.7 x 0.7 mm). Multiplanar image reconstructions were done perpendicular to the acetabulum in oblique coronal and oblique axial planes and in radial planes. Macroscopic and histopathologic examination of the labral specimens was performed. Labral lesions were found in 15/20 hips (75%) on pathologic examination. Six hips demonstrated labral degeneration. The labrum was partially detached in 7 hips and completely detached in 2 hips. A flap-like labrum was found in 2 cases, 1 with partial detachment of the labrum and 1 with a degenerated labrum. Using oblique coronal and oblique axial reconstructions, pathologic findings were confirmed by MRa in 9/15 specimens (sensitivity 60%). There were no false-positive findings (specificity 100%, accuracy 70%). Also, 3/6 labral degenerations without detachment, 4/7 partial detachments, and 2/2 complete detachments were correctly diagnosed. Two flap-like labra were not recognized. With radial reconstructions, pathologic findings were correctly confirmed in 12/15 specimens (sensitivity 80%) without false-positive findings (specificity 100%, accuracy 85%). Also, 3/6 labral degenerations without detachment, 6/7 partial detachments, 2/2 complete detachments, and 1/2 flap-like labra were correctly diagnosed. MRa of the acetabular labrum using radial reconstructions is well suited to delineate the acetabular labrum and to diagnose labral detachments. Radial reconstructions allow for perpendicular display of the whole acetabular circumference and are more accurate for the diagnosis of acetabular labral lesions, when compared with oblique coronal and oblique axial reconstructions.