Investigative Radiology最新文献

{"title":"Perception‑based, Nonuniform Color Mapping for CT Reading.","authors":"Andreas W Landolt, André Euler, Johannes M Froehlich, Rahel A Kubik-Huch","doi":"10.1097/RLI.0000000000001306","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001306","url":null,"abstract":"<p><strong>Background: </strong>With modern CT technology offering faster acquisition, lower radiation exposure, higher resolution, and advanced detector designs, routine image interpretation still relies largely on gray‑scale windowing, which by design requires frequent manual adjustment. Existing color mappings rely on uniform mathematical gradients and offer no clear advantage over gray‑scale display for tissue or structure perception.</p><p><strong>Objective: </strong>To develop and evaluate a software framework supporting interactive exploration of perception‑based color mapping.</p><p><strong>Materials and methods: </strong>A custom research DICOM viewer enabling interactive nonuniform color display was developed. Verification included a contrast‑agent dilution series compared with a clinical viewer and liver phantom CT scans with predefined lesions acquired at varying dose levels and reconstruction settings. Differentiation of tissues and structures in the liver phantom was examined by visual rating after application of different color mappings.</p><p><strong>Results: </strong>Quantitative verification using a contrast-agent dilution series confirmed correct mapping of CT values to color. In a phantom-based reader evaluation using liver phantom CT scans, nonuniform color mapping produced stable visual representations and was significantly preferred in subjective visual analysis.</p><p><strong>Conclusions: </strong>Unlike uniform color mappings, the proposed approach uses nonuniform color ranges to better match human perception. In CT, this may facilitate visual separation of tissues and structures and was preferred in phantom‑based visual assessment compared with standard uniform display methods.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148669546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rationales for Non-standard GBCA Dosing-Low?-High?-When? and Why?: A Literature-based Study.","authors":"Jan Endrikat, Imran Siddiqui, Hassan Khater, Michael Blankenburg","doi":"10.1097/RLI.0000000000001259","DOIUrl":"10.1097/RLI.0000000000001259","url":null,"abstract":"<p><strong>Background: </strong>The current standard dose of extracellular, multipurpose gadolinium-based contrast agents (GBCAs) of 0.1 mmol Gd/kg body weight (bw) was first suggested in 1984, 40 years ago. Although the safety and efficacy of both higher and lower doses (\"non-standard dosing\") have been extensively investigated over the years, the recent introduction of high-relaxivity macrocyclic GBCAs provides, for the first time, a viable lower-dose alternative.</p><p><strong>Objective: </strong>To systematically explore published rationales for nonstandard dosing of GBCAs and discuss the potential future impact of high-relaxivity contrast agents.</p><p><strong>Materials and methods: </strong>A systematic literature review was conducted using Embase and MEDLINE/PubMED, covering studies published from 1991 to 2024. Publications were categorized by clinical indication, administered GBCA dose, study design, and rationale for nonstandard dosing. The dose of 0.1 mmol Gd/kg body weight was defined as the \"standard\" reference for comparison.</p><p><strong>Results: </strong>Eighty-seven publications comparing different nonstandard dosing regimens with the standard dose were finally selected, which included 43 high-dose and 58 low-dose studies. The rationales for using high-dose administration were to achieve better contrast (25/43; 58%) and to improve lesion detection (15/43; 35%). These high-dose studies were performed primarily in the CNS until 2006. Twenty-nine studies (29/43; 67%) reported improved outcomes compared with standard dose, and 1 study (1/43; 2%) reported comparable outcomes. Rationales for using low-dose administration were related to (1) NSF (31/58; 53%); (2) Gd exposure (23/58; 40%); (3) cost (22/58; 38%); (4) unspecified safety (22/58; 38%); (5) Gd retention/presence (19/58; 33%); and (6) the environment (7/58; 12%). From 1991 to 2006, cost was the primary rationale for lower dose administration. From 2008, NSF was noted, from 2017 onward, Gd retention/presence emerged as an identified rationale, and most recently, to minimize environmental impact. Forty-nine of 58 (84%) investigating low-dose regimens reported comparable outcomes, 7 studies (12%) reported inferior outcomes compared with standard dose. However, 36 of the 49 low-dose studies reporting comparable outcomes modified not only the dose but additionally other parameters, or they applied a study design potentially impacting study strength. To reliably allow for a substantially lower dose across a broad range of indications, the next generation of high-relaxivity low-dose GBCAs (gadopiclenol, gadoquatrane) was developed.</p><p><strong>Conclusions: </strong>For over 34 years, there has been a consistent demand to lower GBCA doses, with an increasing number of rationales over time. The high-relaxivity, low-dose mGBCAs show promise for reducing Gd dose while maintaining high image quality, potentially defining a new standard dose.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"575-586"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317906/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145933274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Z Contrast Media for Coronary Photon-counting Detector CT Angiography: Improved Quantification of Calcified Stenoses.","authors":"Tristan T Demmert, Konstantin Klambauer, Bernhard Schmidt, Victor Mergen, Lukas J Moser, Philipp N Maintz, Thomas Allmendinger, Thomas Flohr, Hubertus Pietsch, Matthias Eberhard, Hatem Alkadhi","doi":"10.1097/RLI.0000000000001262","DOIUrl":"10.1097/RLI.0000000000001262","url":null,"abstract":"<p><strong>Background: </strong>Blooming artifacts from calcified plaques can obscure the vessel lumen, leading to overestimation of stenosis severity. Spectral coronary angiography with photon-counting detector CT (PCD-CT) provides virtual monoenergetic images (VMIs) for coronary artery disease assessment. While VMIs at high VMI energy levels reduce calcium blooming, iodine contrast is diminished, limiting diagnostic value. This study evaluated whether contrast media with an atomic number higher than iodine (high-Z) preserve vascular contrast using high VMI energy levels, thereby improving the accuracy of stenosis quantification.</p><p><strong>Methods: </strong>A phantom with 4 and 6 mm diameter rods to mimic small diameter vessels containing eccentric calcified plaques causing 25%, 50%, and 75% diameter stenoses was scanned with a dual-source PCD-CT system. Five different contrast media, including iodine, tungsten, holmium, hafnium, and bismuth, were tested. VMIs were reconstructed from 40 to 190 keV in 1-keV steps. Vessel attenuation, contrast-to-noise ratio (CNR), and stenoses were measured. Qualitative assessment of image quality was performed.</p><p><strong>Results: </strong>Iodine attenuation was high at lower VMI energy levels and dropped below 250 HU at >100 keV. Tungsten, holmium, hafnium, and bismuth maintained >250 HU attenuation throughout the entire energy range. Vessel CNR of iodine was high at lower and decreased at higher VMI energy levels, similar to the CNR of holmium and bismuth, though to a lesser extent. In distinction, CNRs of tungsten and hafnium were lower at lower VMI energy levels and increased to a relatively constant level at higher keV. Tungsten CNR increased with energy, approaching ~40 at high keV. Across all contrast media and stenosis degrees, stenoses were overestimated on low VMI energy levels (24% to 32.5% at 40 keV), while the degree of overestimation decreased at higher VMI energy levels (0% to 13.5% at 190 keV). At 190 keV, tungsten, hafnium, and bismuth showed ≤2.5% stenosis overestimation, compared with iodine (10% to 13.5%). Image quality varied between contrast media and energy levels: new very high-Z contrast media achieved higher scores, while iodine peaked at lower keV (55 to 70 keV) and, due to loss of contrast at higher energies, received the lowest overall scores.</p><p><strong>Conclusions: </strong>As compared with iodine, very high-Z contrast media enable superior lumen definition and more accurate stenosis assessment, also at high VMI energy levels, which minimize calcium blooming.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"568-574"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317894/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146010472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative Analysis of Gadolinium Deposits in Liver Tissue of Patients After Single or Multiple Gadolinium-based Contrast Agent Application.","authors":"Christian Bayerl, Mehrgan Shahryari, Rolf Reiter, Vanessa Proß, Kai Lehmann, Anja A Kühl, Dorit Becker, Andreas Schulz, Carmen Infante-Duarte, Matthias Taupitz, Dominik Geisel, Heiko Tzschätzsch, Jessica Saatz, Heike Traub, Patrick Asbach","doi":"10.1097/RLI.0000000000001254","DOIUrl":"10.1097/RLI.0000000000001254","url":null,"abstract":"<p><strong>Objectives: </strong>Gadolinium-based contrast agents (GBCAs) are widely used in magnetic resonance imaging. Concerns exist regarding gadolinium deposition and its potential histopathologic tissue alterations, especially after repeated administrations of linear, less stable GBCAs. This study aimed to quantify gadolinium mass fractions in liver specimens of subjects exposed to GBCAs in correlation with histopathologic features.</p><p><strong>Materials and methods: </strong>In this Institutional Review Board-approved study, mass fractions of gadolinium in human liver specimens ω(Gd) from 25 subjects who underwent liver tumor resection surgery and had received GBCA (1 to 9 times over 4 y), were quantitatively analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). Histomorphology was assessed based on the nonalcoholic fatty liver disease activity score (NAS). Linear regression analyses were performed with ω(Gd), time and dosage metrics, and histopathologic parameters.</p><p><strong>Results: </strong>The median interval between last GBCA administration and surgery (T) was 14 days (range: 1 to 69 d). Gadolinium was detected in all liver samples (ω(Gd), median: 0.348 µg/g; range: 0.120 to 0.874 µg/g). No significant correlation was found between ω(Gd) and histologic scores, including inflammation and fibrosis. A strong negative correlation was found between ω(Gd) and ln(T) ( P < 0.001). A positive correlation existed between ω(Gd) and the number ( P = 0.010) but not the cumulative dose of previous GBCA administrations ( P = 0.205).</p><p><strong>Conclusions: </strong>Our results suggest that after intravenous administration of GBCA, a small fraction of gadolinium is retained in the liver over a time period of at least several weeks. A relationship was observed between Gadolinium retention and the number of GBCA administrations, but not with the cumulative dose and the degree of fatty liver disease.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"549-558"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317895/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145488761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gadoquatrane in Contrast-enhanced Head-and-neck and Liver Magnetic Resonance Imaging: A Preclinical Dose-Response Study in Pigs.","authors":"Gregor Jost, Jessica Lohrke, Birte Maria Hofmann, Hubertus Pietsch","doi":"10.1097/RLI.0000000000001258","DOIUrl":"10.1097/RLI.0000000000001258","url":null,"abstract":"<p><strong>Objectives: </strong>The objective of the study was to investigate the dose-response (signal enhancement) relationship and signal-enhancement kinetics of gadoquatrane in different anatomic regions employing different MRI pulse sequences. Gadoquatrane is a novel high-relaxivity, extracellular macrocyclic gadolinium-based contrast agent with tetrameric structure that has the potential to be used at lower Gd doses than long-established contrast agents.</p><p><strong>Materials and methods: </strong>In this exploratory, prospective crossover study, 7 healthy pigs underwent contrast-enhanced MRI examinations with gadoquatrane (0.01, 0.03, and 0.06 mmol Gd/kg body weight) and standard doses (0.1 mmol Gd/kg) of 2 comparators, gadobutrol and gadoterate meglumine. MRI was performed on a 1.5T scanner under conditions typically used in clinical routine. Immediately after contrast-agent injection, multiphase liver MRI was done (VIBE sequence). Steady-state head-and-neck MRI followed (spin-echo and FLASH sequences alternating from 2 to 32 min after injection). Image evaluation was based on changes in signal intensity from baseline [relative signal enhancement (RSE)]. Simple linear regression analysis was used to investigate the relationship between RSE and gadoquatrane dose. The regression equations were used to estimate the comparator-equivalent doses of gadoquatrane.</p><p><strong>Results: </strong>The RSE achieved with gadoquatrane in steady-state head-and-neck MRI and multiphase liver MRI increased with dose in all anatomic structures examined, independent of the contrast-agent distribution phase and the pulse sequence employed. Linear regression analysis showed that generally a linear model fitted the dose-response data well ( r2 ≥ 0.84). However, in spin-echo images of the cavernous sinus and VIBE images of the hepatic vein, the areas with the strongest RSE, a disproportionately low RSE was seen with the highest gadoquatrane dose ( r2 of 0.78 and 0.48, respectively).RSE equivalent to the RSE achieved with gadoterate meglumine and gadobutrol at standard dose was achieved with gadoquatrane at doses between 0.031 to 0.039 mmol Gd/kg and 0.040 to 0.049 mmol Gd/kg, respectively. Largely parallel RSE-versus-time curves suggest similar signal-enhancement kinetics for gadoquatrane and the comparators.</p><p><strong>Conclusions: </strong>The study suggests that gadoquatrane, which demonstrated signal-enhancement kinetics similar to those of gadobutrol and gadoterate meglumine, might be utilized effectively at a dose below 0.05 mmol Gd/kg body weight, independent of the anatomic structure investigated and the pulse sequence employed. Overall, the study supports and complements the results of the clinical dose-response study of gadoquatrane.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"559-567"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317911/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145451895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D Freehand Ultrasound Imaging of Optic Nerve Sheath.","authors":"Kai Riemer, Nora Zarranz Bozal, Hendrik Mugele, Giovanni Vinetti, Jay Carr, Connor Howe, Giacomo Strapazzon, Justin Steven Lawley","doi":"10.1097/RLI.0000000000001250","DOIUrl":"10.1097/RLI.0000000000001250","url":null,"abstract":"<p><strong>Objectives: </strong>The optic nerve sheath expands with elevated intracranial pressure, and its diameter is a sensitive proxy measure. While 2D transorbital ultrasound is well-established for detecting elevated intracranial pressure (>20 mm Hg), it shows limited sensitivity to modest or gradual changes, potentially due to geometric assumptions and imaging misalignment. This study introduces freehand 3D ultrasound imaging of the optic nerve sheath to reduce measurement ambiguity and enhance the fidelity of optic nerve sheath assessment as a noninvasive marker of intracranial pressure.</p><p><strong>Materials and methods: </strong>Twelve healthy participants (28.7 ± 8.2 y; 6 females) underwent freehand 3D optic nerve sheath imaging during 24 hours of normobaric hypoxia in an environmental chamber (FiO2 = 13.1%). Scans were acquired in a head-raised (30 degrees) position at baseline, 6, 12, and 24 hours. Cardiorespiratory parameters, cerebral blood flow, and end-tidal gases were recorded. In 6 participants, postural effects were also assessed at baseline. Nutrition and hydration were standardized to 75% of daily requirements.</p><p><strong>Results: </strong>The optic nerve sheath's curved, noncircular shape makes the 2D diameter measurement of the sheath a geometric mismatch and an inadequate descriptor. Probe misalignments of 1.2 mm or 15 degrees led to 2D diameter errors (9%/18.7%) exceeding observer variability (2.6%/3.4%). Freehand 3D imaging was reproducible and yielded more informative metrics, including sheath area and thickness. Internal sheath thickness was more responsive to posture and hypoxia than internal 2D diameter (+31.5%, P = 0.01 vs +2.4%, P = 0.9; +8.2%, P = 0.04 vs +1.8%, P = 0.9). A time effect was observed for internal sheath thickness (P = 0.04), and both area and thickness correlated with internal carotid artery velocity (area: r = 0.9, P = 0.05; thickness: r = 0.8, P = 0.07), consistent with physiological expectations.</p><p><strong>Conclusion: </strong>By eliminating geometric assumptions and misalignment, freehand 3D ultrasound improves the fidelity and sensitivity of optic nerve sheath measurements at the bedside.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":"61 8","pages":"516-526"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317901/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148368360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Practical Rule-of-Thumb to Adapt Contrast Media Dose in Photon-counting Detector CT: The 10-to-5 Rule.","authors":"Cécile R L P N Jeukens, Bibi Martens, Janneke Vandewall, Sören Jasper, Guy Schrijnemaekers, Joachim E Wildberger, Thomas G Flohr","doi":"10.1097/RLI.0000000000001253","DOIUrl":"10.1097/RLI.0000000000001253","url":null,"abstract":"<p><strong>Objectives: </strong>To develop a simple rule-of-thumb on how to reduce the contrast medium (CM) dose in photon-counting detector CT (PCD-CT) when lowering the energy of the reconstructed virtual mono-energetic images (VMI) while maintaining the contrast-to-noise ratio (CNR) for parenchymal CT and CTA.</p><p><strong>Materials and methods: </strong>Spectral abdominal and chest CT phantoms were scanned using a portal venous phase (PVP) abdominal and a high-pitch CTA protocol, respectively, on a first-generation dual-source PCD-CT. The phantoms contained cylindrical rods with iodine in water equivalent material (0.5/1.0/2.0/5.0/10.0/15.0 mg I/mL) and ICRU muscle tissue. The phantoms were complemented with 2 fat equivalent rings to mimic different patient sizes. Iodine contrast, image noise, noise power spectra (NPS), and iodine CNR were investigated in VMIs with different energies (40 to 60 keV in steps of 5 keV). This was done for different iodine concentrations, phantom sizes, x-ray tube voltages (120 kV and 140 kV) and radiation doses. In addition, 15 abdominal and 15 CT angiographic patient scans [body mass index (BMI) range: 17 to 37 kg/m 2 ] were retrospectively analyzed to determine the CNR at different VMI energies.</p><p><strong>Results: </strong>Contrast at a given iodine concentration and VMI energy was independent of phantom size, radiation dose, and acquisition voltage (kV). With decreasing VMI energy, the maximum of the NPS curves increased, while their shape remained similar, indicating higher noise but similar noise texture. The CNR increased with lower VMI energy for a given iodine concentration and phantom size, while CNR decreased with increasing phantom size for a given VMI energy and iodine concentration. When the VMI energy was lowered by 5 keV steps in the range of 60 to 40 keV, similar CNR could be maintained when reducing the iodine concentration at each step by 11.7% to 13.7% for abdominal PVP scans and 11.8% to 14.5% for CTAs. CNR analysis of the patient scans confirmed these findings: a 5 keV reduction in VMI energy led to a mean±SD 11.4%±0.4% and 13.7%±1.0% increase in CNR for abdomen PVP and CTA scans, respectively. This can be translated to a corresponding reduction in CM dose when a constant CNR is aimed for. From these results, a simple, robust rule-of-thumb was derived, the 10-to-5 rule: For the evaluated PCD-CT protocols, CNR can be maintained with about 10% less CM dose for each reduction of the VMI energy by 5 keV.</p><p><strong>Conclusions: </strong>This phantom study, which was complemented with a retrospective proof-of-principle patient study, showed that a simple, easy to implement 10-to-5 rule-of-thumb might be used in daily practice for contrast-enhanced PCD-CT. It allows for individual adaptation of the CM dose to the VMI energy applied.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":"527-536"},"PeriodicalIF":7.9,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13317918/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146112834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accelerated 7T 3D DESS MR Neurography of the Cervical Spine Using CS-CAIPIRINHA and Deep Learning Reconstruction.","authors":"Frederik Abel, Constantin von Deuster, Andreas J Walch, Dominik Paul, Marcel Dominik Nickel, Reto Sutter","doi":"10.1097/RLI.0000000000001305","DOIUrl":"https://doi.org/10.1097/RLI.0000000000001305","url":null,"abstract":"<p><strong>Objective: </strong>To evaluate the potential of combined coherent and incoherent undersampling with deep learning (DL) reconstruction for highly accelerated high-resolution three-dimensional (3D) double-echo steady-state (DESS) MRI of the cervical nerves and rootlets at 7T.</p><p><strong>Methods: </strong>In this prospective study, asymptomatic volunteers underwent 7T MRI of the cervical spine. A high-resolution, 3D DESS sequence (reconstructed voxel size 0.35 mm³ isotropic) with regular 2-fold GRAPPA undersampling served as reference. The sequence was repeated with coherent CAIPIRINHA undersampling alone and combined CAIPIRINHA + incoherent compressed sensing (CS)-based undersampling with DL reconstruction and varying acceleration factors (DL-CAIPIRINHA: R=2 to 12 and DL-CS-CAIPI: R=4 to 16), while all other imaging parameters remained constant. Two fellowship-trained musculoskeletal radiologists assessed image quality, noise, reconstruction and motion artifacts, and edge sharpness of the spinal cord, intradural rootlets/roots, and exiting spinal nerves, including dorsal root ganglia (DRGs), using 5-point Likert scales, with higher scores indicating better image quality or fewer artifacts. Statistics included Friedman and post hoc Wilcoxon signed-rank tests (Benjamini-Hochberg corrected) and κ statistics.</p><p><strong>Results: </strong>Thirty-two volunteers (mean age 30.9±7.2 y; mean BMI 23.4±2.8 kg/m²; 16 females) were included. Image quality significantly improved with 2- and 4-fold DL-CAIPIRINHA (means 4.4 to 4.6) and 4- and 8-fold DL-CS-CAIPI (3.8 to 3.9) compared with GRAPPA (3.2; all P<0.001), and remained comparable with 12-fold DL-CS-CAIPI (P=0.42) despite more than 6-fold reduction in scan time. All DL-based reconstructions reduced noise (P<0.001). Reconstruction artifacts were more pronounced for 12-fold DL-CAIPIRINHA (1.6) than for 12- and 16-fold DL-CS-CAIPI (3.1 to 3.3; P<0.001). Motion artifacts decreased with acceleration factors ≥4 (P<0.001). Sharpness of the spinal cord, intraspinal rootlets/roots, and DRGs was highest with 4-fold DL-CAIPIRINHA (4.2 to 4.7) vs. GRAPPA (2.9 to 3.2; P<0.001). Inter-reader agreement was almost perfect across all imaging features (κ=0.85 to 0.95).</p><p><strong>Conclusions: </strong>Coherent CAIPIRINHA undersampling with DL reconstruction improves image quality over conventional GRAPPA while enabling 50% faster imaging in 7T cervical spine MRI. Adding incoherent CS undersampling permits substantially higher acceleration with preserved image quality and fewer reconstruction artifacts. The novel integration of coherent and incoherent undersampling via combined CAIPIRINHA and CS with DL reconstruction provides a robust framework for preserving image quality at acceleration factors beyond 8, enabling efficient high-resolution cervical spine MRI with scan time reductions exceeding 6-fold.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148578491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra-High-Resolution Dual-Source Photon-Counting CT for Expanded Characterization of Pathophysiological Imaging Patterns in Multiple Myeloma.","authors":"Anke Heidemeier, Henner Huflage, Leo Rasche, K Martin Kortuem, Johannes M Waldschmidt, Hermann Einsele, Thorsten Alexander Bley, Jan-Peter Grunz","doi":"10.1097/RLI.0000000000001304","DOIUrl":"10.1097/RLI.0000000000001304","url":null,"abstract":"<p><strong>Rationale and objectives: </strong>Dual-source photon-counting CT (DS-PCCT) combines spectral imaging with ultra-high spatial resolution for whole-body assessment of multiple myeloma (MM). This study assessed axial and appendicular skeletal manifestations at initial diagnosis by exploiting attenuation characteristics of soft tissue and fat in low-keV virtual monoenergetic images (VMI).</p><p><strong>Materials and methods: </strong>In this retrospective study, 84 patients (67.1±10.5 y, 54 men) underwent whole-body DS-PCCT between November 2024 and December 2025. The sample comprised 53 therapy-naïve MM patients and 31 with precursor conditions (monoclonal gammopathy of undetermined significance, smoldering myeloma, solitary plasmacytoma). Three board-certified radiologists measured CT attenuation of osteolytic lesions and femoral bone marrow at 70 and 40 keV. Long bones were evaluated for diffuse high-grade, nodular, pseudonodular, and fatty marrow patterns, as well as endosteal scalloping.</p><p><strong>Results: </strong>Among 53 MM patients, 40 (75.5%) spectral-morphologic analysis identified 3 patient-level imaging phenotypes of osteolytic bone disease: a soft-tissue-attenuation phenotype (n=25, 47.2%), a fat-attenuation phenotype (n=10, 18.9%), and coexistence of both lesion types (n=5, 9.4%). The pseudonodular pattern was the predominant femoral marrow imaging pattern, whereas fatty marrow (30.2%), nodular lesions (18.9%), and diffuse high-grade infiltration (3.8%) occurred less frequently. Endosteal scalloping occurred exclusively in osteolytic MM (18.9%). Precursor conditions mainly showed fatty (58.1%) and pseudonodular (38.7%) patterns. Low-keV VMI demonstrated distinct energy-dependent attenuation across patterns. Inter-reader agreement for Hounsfield unit measurements was good to excellent (ICC >0.82).</p><p><strong>Conclusions: </strong>DS-PCCT identified a previously undescribed fat-attenuation-predominant imaging phenotype in MM that meets criteria for symptomatic bone disease but is not captured by current International Myeloma Working Group definitions of focal lesions. Spectral-morphologic characterization of marrow involvement may complement existing imaging criteria and aid differentiation between overt MM and nonspecific marrow abnormalities.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148455755","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chest Radiograph-based Artificial Intelligence for Osteoporosis: Accuracy and Associations With Fracture and Mortality.","authors":"Ji Young Lee, Mi-Sook Kim, Jinhee Kim, Eui Jin Hwang","doi":"10.1097/RLI.0000000000001303","DOIUrl":"10.1097/RLI.0000000000001303","url":null,"abstract":"<p><strong>Objectives: </strong>To evaluate an AI tool for opportunistic osteoporosis screening using chest radiographs (CXRs), focusing on its diagnostic accuracy against dual-energy x-ray absorptiometry (DXA) and associations with long-term risks of fracture and mortality.</p><p><strong>Materials and methods: </strong>This retrospective, external validation study included a health checkup cohort with same-day CXR-DXA pairs and a chronic obstructive pulmonary disease (COPD) cohort with available CXRs. We evaluated a commercialized AI tool (InceptionV3 backbone, trained with 55,600 CXR-DXA pairs) designed to identify osteoporosis from a single frontal CXR. Diagnostic performance was assessed against DXA using the area under the receiver operating characteristic curve (AUC). Associations between AI results and subsequent fractures or all-cause mortality were investigated using multivariable Cox proportional-hazard regression, adjusted for sex, age, low body mass index, and COPD stage. Mediation analyses were conducted to examine whether these associations were mediated by a diagnosis of osteoporosis.</p><p><strong>Results: </strong>In total, 8618 (male-to-female ratio, 2882:5736; mean age, 58 y; median follow-up, 2868 d) and 4941 (male-to-female ratio, 4110:831; mean age, 69 y; median follow-up, 2656 d) patients were included in the health checkup and COPD cohorts, respectively. The AI achieved AUCs of 0.94 (95% CI: 0.93-0.95) and 0.81 (95% CI: 0.76-0.87) for osteoporosis identification in the health checkup and COPD cohorts, respectively. Higher AI-predicted osteoporosis probability was associated with subsequent fracture and mortality in both cohorts ( Ps <0.05). Mediation analyses showed that indirect effects of AI scores on fracture or mortality mediated through DXA-defined or clinically diagnosed osteoporosis were not significant ( P s>0.05), suggesting that AI may identify fracture risk in individuals not yet clinically diagnosed with osteoporosis.</p><p><strong>Conclusions: </strong>AI could identify osteoporosis from chest radiographs, and AI results were associated with subsequent fracture and mortality.</p>","PeriodicalId":14486,"journal":{"name":"Investigative Radiology","volume":" ","pages":""},"PeriodicalIF":7.9,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148446800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}