Nonsyndromic arteriopathy and aortopathy and vascular Ehlers-Danlos syndrome causing COL3A1 variants.

Vascular Ehlers-Danlos syndrome (vEDS) is an autosomal dominant genetic disorder characterized by soft connective tissue vulnerability due to dysfunction of Type III collagen and caused by the pathogenic variants in COL3A1 gene. In the era of next-generation sequencing, multiple genes including COL3A1 can be simultaneously analyzed, and among patients suffering from aortopathy even without any other clinical features suggestive of vEDS, pathogenic COL3A1 variants have been increasingly identified. Here, we briefly summarize the characteristics of 12 Japanese patients from 11 families with arteriopathy and pathogenic or likely pathogenic COL3A1 variants in our hospital. Five patients did not have any extra-arterial clinical features, however, the multigene panel testing for hereditary thoracic aortic aneurysm and dissection unexpectedly revealed that two had glycine substitutions in the triple-helical region and three had haploinsufficient type variants in the COL3A1 gene, whose pathogenicities were all classified as pathogenic or likely pathogenic. Further genetic screening and identification of pathogenic variants in patients with nonsyndromic arteriopathy and aortopathy will enable us to develop risk-stratification and management based on the genetic diagnosis.

Recognizing Radiation-induced Changes in the Central Nervous System: Where to Look and What to Look For.

Radiation therapy (RT) continues to play a central role as an effective therapeutic modality for a variety of tumors and vascular malformations in the central nervous system. Although the planning and delivery techniques of RT have evolved substantially during the past few decades, the structures surrounding the target lesion are inevitably exposed to radiation. A wide variety of radiation-induced changes may be observed at posttreatment imaging, which may be confusing when interpreting images. Histopathologically, radiation can have deleterious effects on the vascular endothelial cells as well as on neuroglial cells and their precursors. In addition, radiation induces oxidative stress and inflammation, leading to a cycle of further cellular toxic effects and tissue damage. On the basis of the time of expression, radiation-induced injury can be divided into three phases: acute, early delayed, and late delayed. Acute and early delayed injuries are usually transient and reversible, whereas late delayed injuries are generally irreversible. The authors provide a comprehensive review of the timeline and expected imaging appearances after RT, including the characteristic imaging features after RT with concomitant chemotherapy. Specific topics discussed are imaging features that help distinguish expected posttreatment changes from recurrent disease, followed by a discussion on the role of advanced imaging techniques. Knowledge of the RT plan, the amount of normal structures included, the location of the target lesion, and the amount of time elapsed since RT is highly important at follow-up imaging, and the reporting radiologist should be able to recognize the characteristic imaging features after RT and differentiate these findings from tumor recurrence. ©RSNA, 2020.

Forward-projected Model-based Iterative Reconstruction SoluTion in Temporal Bone Computed Tomography: A Comparison Study of All Reconstruction Modes.

OBJECTIVE: Identify appropriate reconstruction modes of Forward-projected model-based Iterative Reconstruction SoluTion (FIRST) in temporal bone computed tomography (CT) and investigate the contribution of spatial resolution and noise to the visual assessment. METHODS: Sixteen temporal bone CT images were reconstructed. Two blinded radiologists assessed 8 anatomical structures and classified the visual assessment. These visual scores were compared across reconstruction modes among each anatomical structure. Visual scores and contrast-to-noise ratio, noise power spectrum (NPS) at low (NPSLow) and high (NPSHigh) spatial frequencies, and 50% modulation transfer function relationships were evaluated. RESULTS: Visual scores differed significantly for the stapedius muscle and osseous spiral lamina, with CARDIAC SHARP, BONE, and LUNG modes for the osseous spiral lamina scoring highest. Visual scores significantly positively correlated with NPSLow, NPSHigh, and 50% modulation transfer function but negatively with contrast-to-noise ratio. CONCLUSIONS: Modes providing higher spatial resolution and lower noise reduction showed an improved visual assessment of CT images reconstructed with FIRST.

Therapeutic effect of portal vein stenting for portal vein stenosis after upper-abdominal surgery.

BACKGROUND: The therapeutic effect of portal vein (PV) stenting for PV stenosis following nontransplant hepato-pancreato-biliary (HPB) surgery has not been fully investigated. METHODS: Changes in portal venous pressure (PVP) gradient before and after stenting, complications, symptomatic improvement, and stent patency were evaluated. RESULTS: We identified 14 consecutive patients undergoing PV stenting for malignant (n = 8) and benign (n = 6) PV stenosis. Signs of PV stenosis were composed of refractory ascites in 6 patients, varices with hemorrhagic tendencies in 5, and abnormal liver function in 5. The median PVP gradient after PV stenting was 3.0 cm H2O (range, 1.5-3.0), which was significantly smaller than that before PV stenting (median, 15 cm H2O [range, 2.5-25]; P < 0.01). Thirteen out of 14 (93%) achieved clinical success with symptomatic improvement, except one patient with sustained refractory ascites because of peritoneal seeding. During the median follow-up time of 7.3 months (range, 1.0-87), stent occlusion occurred in two patients (14%) because of intrastent tumor growth. The 1-year cumulative stent patency rate was 76% in the entire cohort. CONCLUSIONS: Based on durable effect on patency, we deemed PV stenting for PV stenosis after HPB surgery to be safe and beneficial for improving symptoms.

Small lung tumor biopsy samples are feasible for high quality targeted next generation sequencing.

Next-generation sequencing (NGS) has been implemented in clinical oncology to analyze multiple genes and to guide therapy. In patients with advanced lung cancer, small biopsies such as computed tomography-guided needle biopsy (CTNB), endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and transbronchial biopsy (TBB) are less invasive and are preferable to resection to make a pathological diagnosis. However, the quality of DNA/RNA and NGS from small lung tumor biopsy samples is unknown. Between April 2017 and March 2018, 107 consecutive samples were obtained from thoracic tumors or metastatic sites for targeted NGS analysis. Fifteen samples were obtained through CTNB, 11 through EBUS-TBNA, 11 through TBB and 70 through surgical resection. All samples were formalin-fixed and paraffin-embedded. DNA and RNA quality was measured using the ddCq method and the percentage of RNA fragments above 200 nucleotides (DV200), respectively. Our custommade probes were designed to capture exon sequences of 464 cancer-related genes and transcripts of 463 genes. DNA and RNA yield from the 3 biopsy methods were similar, and less than the yield obtained from resected samples. The quality of DNA and RNA was similar across all methods. Overall, 12 of 15 CTNB samples (80%), all 11 EBUS-TBNA samples, and 9 of 11 TBB samples (82%) underwent successful NGS assays from DNA. NGS analysis from RNA was successful in all 12 CTNB samples, 9 of 11 EBUS-TBNA samples (82%), and 8 of 11 TBB samples (73%). CTNB, EBUS-TBNA and TBB mostly resulted in adequate DNA and RNA quality and enabled high-quality targeted NGS analysis.

Radiation dose reduction with frame rate conversion in X-ray fluoroscopic imaging systems with flat panel detector: basic study and clinical retrospective analysis.

OBJECTIVES: To (a) evaluate the interpolation frames of frame rate conversion (FRC) compared with fluoroscopic frames of conventional method, and (b) compare radiation dose and fluoroscopy time between various clinical examinations without and with FRC retrospectively. METHODS: This study consisted of a basic study and a clinical retrospective analysis. The radiation dosimetry, visual assessment and measurements of contrast to noise ratio were examined. Similarity between interpolation frames and fluoroscopic frames was evaluated using normalised cross-correlation values. In the clinical retrospective analysis approved by the institutional review board, we extracted 270 examinations performed without FRC (conventional group, 12.5 pulses/s) and with FRC (FRC group, 6.25 pulses/s) from 23 May to 31 December 2016. The fluoroscopy parameters and demographics of the two groups of the clinical examinations were compared. Statistical analyses were performed with Wilcoxon signed-rank test, Brunner-Munzel test and χ2 test. RESULTS: In the basic study, the only significant difference was that the radiation dose of FRC was approximately half that of the conventional method in the same fluoroscopy time (p = .031). The interpolation frames of FRC were similar to the fluoroscopic frames of the conventional method. In the clinical retrospective analysis, the only significant difference was that FRC reduced the fluoroscopy dose by 48% and the total dose by 31% compared with the conventional method (p < .001). There was no significant difference in the others. CONCLUSION: FRC significantly reduced the radiation dose without extending the fluoroscopy time and maintaining the image quality compared to the conventional method. KEY POINTS: • Although X-ray fluoroscopic techniques are widely used for various clinical purposes, X-ray fluoroscopic examinations have radiation risks. • Frame rate conversion is an image processing technique for radiation dose reduction. • Clinical retrospective analysis showed that FRC reduces radiation doses of patients.

A comparison between 2- and 3-dimensional approaches to solid component measurement as radiological criteria for sublobar resection in lung adenocarcinoma ≤ 2 cm in size.

PURPOSE: We compared three-dimensional (3D) and two-dimensional (2D) measurements of the solid component to determine radiological criteria for sublobar resection of lung adenocarcinoma ≤ 2 cm in size. METHODS: We included 233 surgical cases. The maximum size of the solid component for 3D measurement was calculated by delineating the solid component on successive axial images and reconstructing the 3D surface model. RESULTS: The predictive performance for adenocarcinoma in situ (n = 43) and minimally invasive adenocarcinoma (n = 77) were equivalent to areas under the curve of 0.871 and 0.857 for 2D and 3D measurements (p = 0.229), respectively. A solid component of 5 mm had a prognostic impact on both measurements ( ≤ 5 mm versus > 5 mm; p = 0.003 for 2D and p = 0.002 for 3D, log-rank test). Survival rates at 5 years were 94.7-96.9% following lobectomy and sublobar resection among patients with a solid component ≤ 5 mm in size. Sublobar resection resulted in worse survival rates, with declines at 5 years of 15.8% on 2D and 11.5% on 3D measurements, than lobectomy in patients with a solid component > 5 mm in size. CONCLUSIONS: A solid component ≤ 5 mm in size is an appropriate criterion for sublobar resection for both measurements. In addition, 2D measurement is justified because of its simple implementation.

Current and Novel Techniques for Metal Artifact Reduction at CT: Practical Guide for Radiologists.

Artifacts caused by metallic implants appear as dark and bright streaks at computed tomography (CT), which severely degrade the image quality and decrease the diagnostic value of the examination. When x-rays pass through a metal object, depending on its size and composition, different physical effects negatively affect the measurements in the detector, most notably the effects of photon starvation and beam hardening. To improve image quality and recover information about underlying structures, several artifact reduction methods have been introduced in modern CT systems. Projection-based metal artifact reduction (MAR) algorithms act in projection space and replace corrupted projections caused by metal with interpolation from neighboring uncorrupted projections. MAR algorithms primarily suppress artifacts that are due to photon starvation. The dual-energy CT technique is characterized by data acquisition at two different energy spectra. Dual-energy CT provides synthesized virtual monochromatic images at different photon energy (kiloelectron volt) levels, and virtual monochromatic images obtained at high kiloelectron volt levels are known to reduce the effects of beam hardening. In clinical practice, although MAR algorithms can be applied after image acquisition, the decision whether to apply dual-energy CT for the patient usually needs to be made before image acquisition. Radiologists should be more familiar with the clinical and technical features of each method and should be able to choose the optimal method according to the clinical situation. ©RSNA, 2018.

Single-energy metal artifact reduction technique for reducing metallic coil artifacts on post-interventional cerebral CT and CT angiography.

PURPOSE: To evaluate the effects of the single-energy metal artifact reduction (SEMAR) algorithm on image quality of cerebral CT and CT angiography (CTA) for patients who underwent intracranial aneurysm coiling. METHODS: Twenty patients underwent cerebral CT and CTA using a 320-detector row CT after intracranial aneurysm coiling. Images with and without application of the SEMAR algorithm (SEMAR CT and standard CT images, respectively) were reconstructed for each patient. The images were qualitatively assessed by two independent radiologists in a blinded manner for the depiction of anatomical structures around the coil, delineation of the arteries around the coil, and the depiction of the status of coiled aneurysms. Artifact strength was quantitatively assessed by measuring the standard deviation of attenuation values around the coil. RESULTS: The strength of artifacts measured in SEMAR CT images was significantly lower than that in standard CT images (25.7 ± 10.2 H.U. vs. 80.4 ± 67.2 H.U., p < 0.01, Student's paired t test). SEMAR CT images were significantly improved compared with standard CT images in the depiction of anatomical structures around the coil (p < 0.01, the sign test), delineation of the arteries around the coil (p < 0.01), and the depiction of the status of coiled aneurysms (p < 0.01). CONCLUSION: The SEMAR algorithm significantly reduces metal artifacts from intracranial aneurysm coiling and improves visualization of anatomical structures and arteries around the coil, and depiction of the status of coiled aneurysms on post-interventional cerebral CT.

Full and hybrid iterative reconstruction to reduce artifacts in abdominal CT for patients scanned without arm elevation.

Background Abdominal computed tomography (CT) without arm elevation is associated with degraded image quality due to streak artifacts. Purpose To compare the degree of streak artifacts in abdominal CT images without arm elevation between full iterative reconstruction (IR), hybrid IR, and filtered back projection (FBP) using two commercially available scanners. Material and Methods First, a phantom study simulating CT examination without arm elevation was performed. Second, unenhanced axial images of 33 patients (17 and 16 patients for each vendor) who underwent CT without arm elevation were reconstructed with full IR, hybrid IR and FBP. A radiologist placed 50 parallel lines with lengths of 50 pixels vertical to the streaks and quantitatively evaluated the images for streak artifacts in the phantom study. Two radiologists evaluated the images of patients for streak artifacts (on the liver and the kidney) and diagnostic acceptability using a four-point scale. Results The phantom study indicated that full IR algorithms were more effective than FBP in reducing streak artifacts. In the clinical patient study, streak artifacts were significantly more reduced with full IR compared with FBP in both the liver and kidney ( P < 0.012). Streak artifact reduction was limited with hybrid IR. Model-based iterative reconstruction (MBIR) (one of the full IR algorithms) provided diagnostically more acceptable image quality ( P < 0.016) compared with FBP. Conclusion In abdominal CT without arm elevation, full IR enabled a more efficient streak artifact reduction compared with FBP and MBIR was associated with diagnostically more acceptable images.

[Fluoroscopy dose reduction of computed tomography guided chest interventional radiology using real-time iterative reconstruction].

The purpose of this study was to evaluate the radiation dose reduction to patients and radiologists in computed tomography (CT) guided examinations for the thoracic region using CT fluoroscopy. Image quality evaluation of the real-time filtered back-projection (RT-FBP) images and the real-time adaptive iterative dose reduction (RT-AIDR) images was carried out on noise and artifacts that were considered to affect the CT fluoroscopy. The image standard deviation was improved in the fluoroscopy setting with less than 30 mA on 120 kV. With regard to the evaluation of artifact visibility and the amount generated by the needle attached to the chest phantom, there was no significant difference between the RT-FBP images with 120 kV, 20 mA and the RT-AIDR images with low-dose conditions (greater than 80 kV, 30 mA and less than 120 kV, 20 mA). The results suggest that it is possible to reduce the radiation dose by approximately 34% at the maximum using RT-AIDR while maintaining image quality equivalent to the RT-FBP images with 120 V, 20 mA.

A Case of Ruptured Exophytic Uterine Artery Pseudoaneurysm without Specific Risk Factors That Manifested Seven Days after Vaginal Delivery.

A uterine artery pseudoaneurysm (UAP) is a life-threatening complication during pregnancy and postpartum. Early diagnosis of exophytic UAP rupture is difficult due to the absence of vaginal bleeding. This study reports the case of a 31-year-old postpartum woman who presented with abdominal pain and fever seven days after vaginal delivery, without symptoms of maternal shock. Ultrasonography revealed a ruptured exophytic UAP with hemoperitoneum, which was confirmed using computed tomography. Interventional radiology confirmed that the site of the pseudoaneurysm was at the level of the uterine artery bifurcation, and embolization was performed immediately after diagnosis using a coil and n-butyl-2-cyanoacrylate. The patient's symptoms were relieved, and she was discharged 12 days after the embolization. At eight months postpartum, the UAP was not visible on transvaginal ultrasonography. Exophytic UAP can occur even in the absence of specific risk factors such as cesarean section or endometriosis, and the UAP may not necessarily rupture immediately after delivery. Obstetricians must remain aware of the possibility of exophytic UAP rupture manifesting as abdominal pain with postpartum fever, rather than as unstable vital signs. This is the first report of an exophytic UAP that occurred at the level of the uterine artery bifurcation. Identification of the sites where exophytic UAP can occur can aid in the early diagnosis of the condition.

Effects of muscle relaxants on mask ventilation in anesthetized persons with normal upper airway anatomy.

BACKGROUND: Recent studies suggest advantages of muscle relaxants for facemask ventilation. However, direct effects of muscle relaxants on mask ventilation remain unclear because these studies did not control mechanical factors influencing ventilation. We tested a hypothesis that muscle relaxants, either rocuronium or succinylcholine, improve mask ventilation. METHODS: In anesthetized adult persons with normal upper airway anatomy, tidal volumes during facemask ventilation were measured while maintaining the neutral head and mandible positions and the airway pressures of a ventilator before and during muscle paralysis induced by either rocuronium (n=14) or succinylcholine (n=17). Tidal volumes of oral and nasal airway routes were separately measured with a custom-made oronasal portioning full facemask. Behavior of the oral airway was observed by an endoscope in six additional subjects receiving succinylcholine. RESULTS: Total, oral, and nasal tidal volumes did not significantly change at complete muscle paralysis with rocuronium. In contrast, succinylcholine significantly increased total tidal volumes at 60 s after its administration (mean±SD; 4.2±2.1 vs. 5.4±2.6 ml/kg, P=0.02) because of increases of ventilation through both airway routes. Abrupt tidal volume increase occurred more through oral airway route than nasal route. Dilation of the space at the isthmus of the fauces was endoscopically observed during pharyngeal fasciculation in all six subjects. CONCLUSIONS: Rocuronium did not deteriorate facemask ventilation, and it was improved after succinylcholine administration in association with airway dilation during pharyngeal fasciculation. This effect continued to a lesser degree after resolution of the fasciculation.

Model-based iterative reconstruction technique for radiation dose reduction in chest CT: comparison with the adaptive statistical iterative reconstruction technique.

OBJECTIVES: To prospectively evaluate dose reduction and image quality characteristics of chest CT reconstructed with model-based iterative reconstruction (MBIR) compared with adaptive statistical iterative reconstruction (ASIR). METHODS: One hundred patients underwent reference-dose and low-dose unenhanced chest CT with 64-row multidetector CT. Images were reconstructed with 50 % ASIR-filtered back projection blending (ASIR50) for reference-dose CT, and with ASIR50 and MBIR for low-dose CT. Two radiologists assessed the images in a blinded manner for subjective image noise, artefacts and diagnostic acceptability. Objective image noise was measured in the lung parenchyma. Data were analysed using the sign test and pair-wise Student's t-test. RESULTS: Compared with reference-dose CT, there was a 79.0 % decrease in dose-length product with low-dose CT. Low-dose MBIR images had significantly lower objective image noise (16.93 ± 3.00) than low-dose ASIR (49.24 ± 9.11, P < 0.01) and reference-dose ASIR images (24.93 ± 4.65, P < 0.01). Low-dose MBIR images were all diagnostically acceptable. Unique features of low-dose MBIR images included motion artefacts and pixellated blotchy appearances, which did not adversely affect diagnostic acceptability. CONCLUSION: Diagnostically acceptable chest CT images acquired with nearly 80 % less radiation can be obtained using MBIR. MBIR shows greater potential than ASIR for providing diagnostically acceptable low-dose CT images without severely compromising image quality. KEY POINTS: • Model-based iterative reconstruction (MBIR) creates high-quality low-dose CT images. • MBIR significantly improves image noise and artefacts over adaptive statistical iterative techniques. • MBIR shows greater potential than ASIR for diagnostically acceptable low-dose CT. • The prolonged processing time of MBIR may currently limit its routine use in clinical practice.

Assessment of neuromuscular block at the orbicularis oris, corrugator supercilii, and adductor pollicis muscles.

PURPOSE: We studied neuromuscular block at the orbicularis oris, corrugator supercilii, and adductor pollicis muscles in anesthetized patients. METHODS: Fifty-four adult patients undergoing air-oxygen-sevoflurane-fentanyl and epidural anesthesia were randomly divided into orbicularis oris, corrugator supercilii, and adductor pollicis groups of 18 patients each. In the three groups, the degree of neuromuscular block caused by rocuronium 0.6 mg/kg was monitored at the orbicularis oris, corrugator supercilii, and adductor pollicis muscles acceleromyographically. RESULTS: Onset of neuromuscular block did not significantly differ among the three groups [157 ± 60, 186 ± 73, and 148 ± 45 s; mean ± standard deviation (SD)]. Minimum value of 1st stimulation in train-of-four (T1)/control at the corrugator supercilii group was significantly higher than in the orbicularis oris and adductor pollicis groups (0.108 ± 0.066 vs. 0.021 ± 0.024 and 0.002 ± 0.007; P < 0.001). T1/control at the orbicularis oris group was significantly higher than at the adductor pollicis group 30 min after rocuronium (P < 0.05). T1/control at the corrugator supercilii group was significantly higher than at the orbicularis oris and adductor pollicis groups 10-30 and 10-40 min, respectively, after rocuronium (P < 0.05). Train-of-four ratios at the orbicularis oris and corrugator supercilii groups were significantly higher than at the adductor pollicis group 40-120 min after rocuronium (P < 0.05). CONCLUSION: The corrugator supercilii muscle is more resistant to rocuronium than the orbicularis oris and adductor pollicis muscles. Recovery of neuromuscular block at the orbicularis oris muscle is slower than that at the corrugator supercilii muscle but was faster than that at the adductor pollicis muscle.

A displaced bronchus branching from the left main bronchus and bifurcating into the apicoposterior and anterior bronchi of the left upper lobe in a healthy adult male: A case report.

A displaced left upper bronchus is a rare anomaly. We report the case of a 45-year-old man with a displaced bronchus, branching from the left main bronchus and bifurcating into the apicoposterior and anterior segment bronchi of the left upper lobe. The displaced bronchus passed behind the left pulmonary artery. To our knowledge, 12 similar cases of displaced bronchi have been reported to date. Displaced bronchi are difficult to detect prospectively on computed tomography. However, evaluating the accessory fissures may help establish an accurate diagnosis.

Massive hemoptysis managed by prolonged anticoagulation-free veno-venous extracorporeal membrane oxygenation with which thoracic surgeries were accompanied: a case report.

BACKGROUND: Massive hemoptysis causing inadequate ventilation results in life-threatening consequences. We present a patient who developed respiratory insufficiency produced by bronchiectatic massive hemoptysis and underwent prolonged anticoagulation-free veno-venous extracorporeal membrane oxygenation (VV-ECMO) during which thoracic surgeries were performed. CASE PRESENTATION: A 79-year-old woman suffered massive hemoptysis resulting in respiratory failure during fiberoptic bronchoscopy. Bronchial intubation followed by one lung ventilation failed to ensure adequate oxygenation. Anticoagulation-free VV-ECMO, therefore, was installed immediately. Since conservative hemostatic measures including bronchial arterial embolization were not effective, resection of the culprit lung was performed while on VV-ECMO. Next day an exploratory thoracotomy and intercostal artery embolization were needed for recurrent bleeding. The VV-ECMO was withdrawn after five days of operation. CONCLUSIONS: Massive hemoptysis can be fatal and needs instantaneous and intensive treatments. In our case, long-term anticoagulation-free VV-ECMO during which thoracic surgeries and endovascular interventions were performed provided a favorable outcome.

Chronic nicotinamide mononucleotide supplementation elevates blood nicotinamide adenine dinucleotide levels and alters muscle function in healthy older men.

Preclinical studies have revealed that the elevation of nicotinamide adenine dinucleotide (NAD + ) upon the administration of nicotinamide mononucleotide (NMN), an NAD + precursor, can mitigate aging-related disorders; however, human data on this are limited. We investigated whether the chronic oral supplementation of NMN can elevate blood NAD + levels and alter physiological dysfunctions in healthy older participants. We administered 250 mg NMN per day to aged men for 6 or 12 weeks in a placebo-controlled, randomized, double-blind, parallel-group trial. Chronic NMN supplementation was well tolerated and caused no significant deleterious effect. Metabolomic analysis of whole blood samples demonstrated that oral NMN supplementation significantly increased the NAD + and NAD + metabolite concentrations. There were nominally significant improvements in gait speed and performance in the left grip test, which should be validated in larger studies; however, NMN exerted no significant effect on body composition. Therefore, chronic oral NMN supplementation can be an efficient NAD + booster for preventing aging-related muscle dysfunctions in humans.

Postsurgical spinal magnetic resonance imaging with iterative decomposition of water and fat with echo asymmetry and least-squares estimation.

OBJECTIVE: Magnetic resonance imaging (MRI) is the most popular follow-up study for patients who have undergone spinal surgery. However, the image quality often becomes poor because of artifacts from metal implants and/or from failed fat suppression, which obscure diagnosis. Iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) is a new fat suppression method that is less affected by inhomogeneity of the magnetic field. Here, we compared postsurgical spinal MRI with IDEAL versus chemical shift selective saturation (CHESS). METHODS: For 35 patients who had spinal surgery, we examined T2-weighted fast spin-echo sagittal images of the spine with both IDEAL and CHESS. Two radiologists evaluated the degrees of fat suppression and spinal canal projection from 0 (least/worst) to 2 (most/best). RESULTS: Fat suppression and spinal canal scores for IDEAL were statistically higher than those for CHESS (P < 0.05). CONCLUSIONS: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation is clinically useful for postoperative spinal MRI.