Can ultra-low-dose computed tomography reliably diagnose and classify maxillofacial fractures in the clinical routine?

Purpose: Maxillofacial trauma predominantly affects young adults between 20 and 40 years of age. Although radioprotection is a legal requirement, the significant potential of dose reduction in computed tomography (CT) is still underused in the clinical routine. The objective of this study was to evaluate whether maxillofacial fractures can be reliably detected and classified using ultra-low-dose CT. Materials and Methods: CT images of 123 clinical cases with maxillofacial fractures were classified by two readers using the AOCOIAC software and compared with the corresponding results from post-treatment images. In group 1, consisting of 97 patients with isolated facial trauma, pre-treatment CT images at different dose levels (volumetric computed tomography dose index: ultra-low dose, 2.6 mGy; low dose, <10 mGy; and regular dose, <20 mGy) were compared with post-treatment cone-beam computed tomography (CBCT). In group 2, consisting of 31 patients with complex midface fractures, pre-treatment shock room CT images were compared with post-treatment CT at different dose levels or CBCT. All images were presented in random order and classified by 2 readers blinded to the clinical results. All cases with an unequal classification were re-evaluated. Results: In both groups, ultra-low-dose CT had no clinically relevant effect on fracture classification. Fourteen cases in group 2 showed minor differences in the classification code, which were no longer obvious after comparing the images directly to each other. Conclusion: Ultra-low-dose CT images allowed the correct diagnosis and classification of maxillofacial fractures. These results might lead to a substantial reconsideration of current reference dose levels.

Absence of Stress Hyperglycemia Indicates the Most Severe Form of Blunt Liver Trauma.

BACKGROUND: Stress hyperglycemia is common in trauma patients. Increasing injury severity and hemorrhage trigger hepatic gluconeogenesis, glycogenolysis, peripheral and hepatic insulin resistance. Consequently, we expect glucose levels to rise with injury severity in liver, kidney and spleen injuries. In contrast, we hypothesized that in the most severe form of blunt liver injury, stress hyperglycemia may be absent despite critical injury and hemorrhage. METHODS: All patients with documented liver, kidney or spleen injuries, treated at a university hospital between 2000 and 2020 were charted. Demographic, laboratory, radiological, surgical and other data were analyzed. RESULTS: A total of 772 patients were included. In liver (n = 456), spleen (n = 375) and kidney (n = 152) trauma, an increase in injury severity past moderate to severe (according to the American Association for the Surgery of Trauma, AAST III-IV) was associated with a concomitant rise in blood glucose levels independent of the affected organ. While stress-induced hyperglycemia was even more pronounced in the most severe forms (AAST V) of spleen (median 10.7 mmol/L, p < 0.0001) and kidney injuries (median 10.6 mmol/L, p = 0.004), it was absent in AAST V liver injuries, where median blood glucose level even fell (5.6 mmol/L, p < 0.0001). CONCLUSIONS: Absence of stress hyperglycemia on hospital admission could be a sign of most severe liver injury (AAST V). Blood glucose should be considered an additional diagnostic criterion for grading liver injury.

Dabigatran Added to Dual Antiplatelet Therapy to Treat a Left Ventricular Thrombus in an 87 Year Old Patient With Myocardial Infarction and Very High Bleeding Risk.

Background: A left ventricular (LV) thrombus is detected in approximately 5-10% of patients after myocardial infarction (MI). If left untreated, these LV thrombi carry a significant risk of complications including embolic stroke. According to current guidelines, anticoagulation with vitamin K antagonists (VKA) is recommended to treat a LV thrombus. Case presentation: An 87 year old patient was referred to our department with non ST-elevation MI. Five months before, he had been diagnosed with a subacute ST elevation MI, which had been treated conservatively. Recently, a rectal neoplasia had been diagnosed, but not operated yet. The patient underwent coronary angiography with implantation of two drug eluting stents (Cre8) requiring dual antiplatelet therapy. During ventriculography an apical LV thrombus of 16 mm diameter was detected. Due to the high bleeding risk in this patient, VKA therapy with potentially fluctuating international normalized ratio (INR) values was considered unsuitable. Therefore, dabigatran at a dose of 110 mg bid was chosen as anticoagulation therapy. After 4 weeks, cardiac computed tomography was performed, which failed to detect the LV thrombus described previously. Notably, triple therapy with dabigatran, clopidogrel, and aspirin was well tolerated without evidence for bleeding. The surgical resection of the rectal neoplasm was performed 2 months later without bleeding complications. Discussion: Anticoagulation is effective in patients with MI and a LV thrombus in reducing the risk of embolization and in dissolving the thrombus. Our case is complex due to the required triple therapy, very old age and significant bleeding risk of our patient due to the rectal neoplasia. Although only few reports are available for the use of non VKA oral anticoagulants (NOAC) in this indication, we chose dabigatran at a dose of 110 mg bid added to dual antiplatelet therapy for our patient. Besides the advantage of a predictable pharmacokinetic profile of NOAC in contrast to VKA, the effect of dabigatran can rapidly be reversed by idaruzicumab in the case of severe bleeding. Conclusion remarks: Physicians should carefully weigh the risk of thromboembolic events versus the risk of bleeding when combining antiplatelet with anticoagulation therapy.

Ulna Rotation Osteotomy in Complete Dislocation of the Distal Radioulnar Joint.

Background Complete dislocation of the distal radioulnar joint (DRUJ) is a rare injury. Dislocation can present as uni- or multidirectional, acute or chronic, reducible or irreducible. It can occur due to isolated loss of ligamentous restraints or more frequent in Galeazzi - or Essex-Lopresti-type fractures. Case Description A 28-year-old man sustained a distal radius fracture and presented after conservative treatment with blocked supination. Examination revealed a malunion of the distal radius in combination with an irreducible dorsal dislocation of the DRUJ. Corrective osteotomy of the distal radius was performed, the DRUJ was reduced, and the ulnar avulsed triangular fibrocartilage complex (TFCC) refixed with transosseous sutures. Redislocation occurred 8 weeks later. Revision surgery showed a palmar dislocated TFC fixed in a palmar scar formation along the distal interosseous membrane (DIOM). The scar was released and a rotation osteotomy of the distal ulna was performed. At follow-up, the patient was pain-free, had good range of motion, and returned to work and sport activities. Literature Review For reconstruction of chronic complete dislocations of the DRUJ, ligament plasty procedures are described. In case of additional cartilage damage, salvage procedures are recommended. Clinical Relevance We report a procedure in which the rotation of the distal ulna is corrected to restore DRUJ congruity in chronic dislocations. The rotation osteotomy described is useful in gross ligamentous instability following loss of constraint by the TFCC and the DIOM.

Spatial and contrast resolution of ultralow dose dentomaxillofacial CT imaging using iterative reconstruction technology.

OBJECTIVES: The objective of this study was to determine how iterative reconstruction technology (IRT) influences contrast and spatial resolution in ultralow-dose dentomaxillofacial CT imaging. METHODS: A polymethyl methacrylate phantom with various inserts was scanned using a reference protocol (RP) at CT dose index volume 36.56 mGy, a sinus protocol at 18.28 mGy and ultralow-dose protocols (LD) at 4.17 mGy, 2.36 mGy, 0.99 mGy and 0.53 mGy. All data sets were reconstructed using filtered back projection (FBP) and the following IRTs: adaptive statistical iterative reconstructions (ASIRs) (ASIR-50, ASIR-100) and model-based iterative reconstruction (MBIR). Inserts containing line-pair patterns and contrast detail patterns for three different materials were scored by three observers. Observer agreement was analyzed using Cohen's kappa and difference in performance between the protocols and reconstruction was analyzed with Dunn's test at α = 0.05. RESULTS: Interobserver agreement was acceptable with a mean kappa value of 0.59. Compared with the RP using FBP, similar scores were achieved at 2.36 mGy using MBIR. MIBR reconstructions showed the highest noise suppression as well as good contrast even at the lowest doses. Overall, ASIR reconstructions did not outperform FBP. CONCLUSIONS: LD and MBIR at a dose reduction of >90% may show no significant differences in spatial and contrast resolution compared with an RP and FBP. Ultralow-dose CT and IRT should be further explored in clinical studies.

Ultralow dose dentomaxillofacial CT imaging and iterative reconstruction techniques: variability of Hounsfield units and contrast-to-noise ratio.

OBJECTIVE: The aim of this study was to evaluate whether application of ultralow dose protocols and iterative reconstruction technology (IRT) influence quantitative Hounsfield units (HUs) and contrast-to-noise ratio (CNR) in dentomaxillofacial CT imaging. METHODS: A phantom with inserts of five types of materials was scanned using protocols for (a) a clinical reference for navigated surgery (CT dose index volume 36.58 mGy), (b) low-dose sinus imaging (18.28 mGy) and (c) four ultralow dose imaging (4.14, 2.63, 0.99 and 0.53 mGy). All images were reconstructed using: (i) filtered back projection (FBP); (ii) IRT: adaptive statistical iterative reconstruction-50 (ASIR-50), ASIR-100 and model-based iterative reconstruction (MBIR); and (iii) standard (std) and bone kernel. Mean HU, CNR and average HU error after recalibration were determined. Each combination of protocols was compared using Friedman analysis of variance, followed by Dunn's multiple comparison test. RESULTS: Pearson's sample correlation coefficients were all >0.99. Ultralow dose protocols using FBP showed errors of up to 273 HU. Std kernels had less HU variability than bone kernels. MBIR reduced the error value for the lowest dose protocol to 138 HU and retained the highest relative CNR. ASIR could not demonstrate significant advantages over FBP. CONCLUSIONS: Considering a potential dose reduction as low as 1.5% of a std protocol, ultralow dose protocols and IRT should be further tested for clinical dentomaxillofacial CT imaging. ADVANCES IN KNOWLEDGE: HU as a surrogate for bone density may vary significantly in CT ultralow dose imaging. However, use of std kernels and MBIR technology reduce HU error values and may retain the highest CNR.

Ultralow-dose CT of the craniofacial bone for navigated surgery using adaptive statistical iterative reconstruction and model-based iterative reconstruction: 2D and 3D image quality.

OBJECTIVE. The purpose of this article is to evaluate 2D and 3D image quality of high-resolution ultralow-dose CT images of the craniofacial bone for navigated surgery using adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR) in comparison with standard filtered backprojection (FBP). MATERIALS AND METHODS. A formalin-fixed human cadaver head was scanned using a clinical reference protocol at a CT dose index volume of 30.48 mGy and a series of five ultralow-dose protocols at 3.48, 2.19, 0.82, 0.44, and 0.22 mGy using FBP and ASIR at 50% (ASIR-50), ASIR at 100% (ASIR-100), and MBIR. Blinded 2D axial and 3D volume-rendered images were compared with each other by three readers using top-down scoring. Scores were analyzed per protocol or dose and reconstruction. All images were compared with the FBP reference at 30.48 mGy. A nonparametric Mann-Whitney U test was used. Statistical significance was set at p < 0.05. RESULTS. For 2D images, the FBP reference at 30.48 mGy did not statistically significantly differ from ASIR-100 at 3.48 mGy, ASIR-100 at 2.19 mGy, and MBIR at 0.82 mGy. MBIR at 2.19 and 3.48 mGy scored statistically significantly better than the FBP reference (p = 0.032 and 0.001, respectively). For 3D images, the FBP reference at 30.48 mGy did not statistically significantly differ from all reconstructions at 3.48 mGy; FBP and ASIR-100 at 2.19 mGy; FBP, ASIR-100, and MBIR at 0.82 mGy; MBIR at 0.44 mGy; and MBIR at 0.22 mGy. CONCLUSION. MBIR (2D and 3D) and ASIR-100 (2D) may significantly improve subjective image quality of ultralow-dose images and may allow more than 90% dose reductions.

Durable complete remission in a patient with recurrent DLBCL receiving rituximab monotherapy after high-dose chemotherapy and autologous stem cell transplantation.

The optimal management of patients with diffuse large B cell lymphoma relapsing after autologous haematopoetic stem cell transplantation (HCT) is difficult and no standard treatment has been defined. The authors here report the case of a rituximab-naive patient who relapsed after HCT and was cured with rituximab monotherapy.

Reproducibility of left and right ventricular mass measurements with cardiac CT.

BACKGROUND: Cardiac CT provides volumetric data that enables characterization of the myocardium. OBJECTIVE: We evaluated intraobserver, interobserver, and interstudy reproducibility of left ventricular (LV) and right ventricular (RV) mass quantification with cardiac CT. METHODS: Thirty-eight patients who underwent cardiac CT twice within 365 days were included in this analysis. Functional reconstructions in 10% steps throughout the R-R interval and axial 1.5-mm sections were used. Semiautomatic contour detection was used to trace epicardial and endocardial borders in all cardiac phases for calculation of LV and RV ejection fraction, end-diastolic volume, end-systolic volume, cardiac output, stroke volume, and ventricular mass. For each study 2 observers measured LV and RV mass twice. RESULTS: LV mass parameters derived from semiautomatic contour detection algorithm had excellent intraobserver (r = 1.00), interobserver (r = 0.99), and interstudy (r = 0.99) reproducibility (P < 0.0001). Average end-diastolic LV mass was 146.2 ± 42.9 g at the first CT study and 146.8 ± 44.4 g at the second study. For measuring RV mass, reproducibility was good on all levels (r = 0.78, r = 0.78, and r = 0.68, respectively, with an average end-diastolic mass of 25.7 ± 5.8 g at the first study and 24.4 ± 4.8 g at the second study. CONCLUSION: Quantification of LV mass at cardiac CT with the threshold-based, region-growing semiautomatic segmentation analysis software evaluated here is highly observer independent and reproducible. This largely holds true for the estimation of RV mass as well; however, further improvements are needed to optimize reproducibility for RV mass quantification.

Persistent median artery in the carpal tunnel: color Doppler ultrasonographic findings.

OBJECTIVE: To describe the ultrasonographic and color Doppler ultrasonographic findings in 2 patients with carpal tunnel syndrome associated with a persistent median artery and to report the frequency of this anatomic variation in healthy volunteers. METHODS: Two patients with the clinical appearance of carpal tunnel syndrome and 100 wrists and distal forearms of 50 asymptomatic volunteers were examined with ultrasonography and color Doppler ultrasonography. The frequency and size of a persistent median artery and its relationship to median nerve anatomy in the carpal tunnel were evaluated. RESULTS: A large persistent median artery of 3 mm in diameter was found in the affected hands in both patients with carpal tunnel syndrome. Findings were confirmed at surgery. Among the asymptomatic volunteers, a persistent median artery could be found in 13 (26%, 10 [20%] unilateral and 3 [6%] bilateral), with a mean diameter of 1.1 mm (range, 0.5-1.7 mm). In 10 (63%) of 16 hands, the persistent median artery was associated with high division of the median nerve or a bifid nerve configuration in the carpal tunnel. CONCLUSIONS: A persistent median artery is a common condition in healthy individuals and in most cases is related to median nerve variations such as high division or a bifid nerve. Because a persistent median artery has a superficial course close to the transverse carpal ligament, preoperative diagnosis of this anatomic variation may be of clinical importance.