Negative effects of iodine-based contrast agent on renal function in patients with moderate reduced renal function hospitalized for COVID-19.

BACKGROUND: Kidney disease and renal failure are associated with hospital deaths in patients with COVID - 19. We aimed to test if contrast enhancement affects short-term renal function in hospitalized COVID - 19 patients. METHODS: Plasma creatinine (P-creatinine) was measured on the day of computed tomography (CT) and 24 h, 48 h, and 4-10 days after CT. Contrast-enhanced (n = 142) and unenhanced (n = 24) groups were subdivided, based on estimated glomerular filtration rates (eGFR), > 60 and ≤ 60 ml/min/1.73 m2. Contrast-induced acute renal failure (CI-AKI) was defined as ≥27 µmol/L increase or a > 50% rise in P-creatinine from CT or initiation of renal replacement therapy during follow-up. Patients with renal replacement therapy were studied separately. We evaluated factors associated with a > 50% rise in P-creatinine at 48 h and at 4-10 days after contrast-enhanced CT. RESULTS: Median P-creatinine at 24-48 h and days 4-10 post-CT in patients with eGFR> 60 and eGFR≥30-60 in contrast-enhanced and unenhanced groups did not differ from basal values. CI-AKI was observed at 48 h and at 4-10 days post contrast administration in 24 and 36% (n = 5/14) of patients with eGFR≥30-60. Corresponding figures in the eGFR> 60 contrast-enhanced CT group were 5 and 5% respectively, (p < 0.037 and p < 0.001, Pearson χ2 test). In the former group, four of the five patients died within 30 days. Odds ratio analysis showed that an eGFR≥30-60 and 30-day mortality were associated with CK-AKI both at 48 h and 4-10 days after contrast-enhanced CT. CONCLUSION: Patients with COVID - 19 and eGFR≥30-60 had a high frequency of CK-AKI at 48 h and at 4-10 days after contrast administration, which was associated with increased 30-day mortality. For patients with eGFR≥30-60, we recommend strict indications are practiced for contrast-enhanced CT. Contrast-enhanced CT had a modest effect in patients with eGFR> 60.

Widespread Parenchymal Abnormalities and Pulmonary Embolism on Contrast-Enhanced CT Predict Disease Severity and Mortality in Hospitalized COVID-19 Patients.

Purpose: Severe COVID-19 is associated with inflammation, thromboembolic disease, and high mortality. We studied factors associated with fatal outcomes in consecutive COVID-19 patients examined by computed tomography pulmonary angiogram (CTPA). Methods: This retrospective, single-center cohort analysis included 130 PCR-positive patients hospitalized for COVID-19 [35 women and 95 men, median age 57 years (interquartile range 51-64)] with suspected pulmonary embolism based on clinical suspicion. The presence and extent of embolism and parenchymal abnormalities on CTPA were recorded. The severity of pulmonary parenchymal involvement was stratified by two experienced radiologists into two groups: lesions affecting ≤50% or >50% of the parenchyma. Patient characteristics, radiological aspects, laboratory parameters, and 60-day mortality data were collected. Results: Pulmonary embolism was present in 26% of the patients. Most emboli were small and peripheral. Patients with widespread parenchymal abnormalities, with or without pulmonary embolism, had increased main pulmonary artery diameter (p < 0.05) and higher C-reactive protein (p < 0.01), D-dimer (p < 0.01), and troponin T (p < 0.001) and lower hemoglobin (p < 0.001). A wider main pulmonary artery diameter correlated positively with C-reactive protein (r = 0.28, p = 0.001, and n = 130) and procalcitonin. In a multivariant analysis, D-dimer >7.2 mg/L [odds ratio (±95% confidence interval) 4.1 (1.4-12.0)] and ICU stay were significantly associated with embolism (p < 0.001). The highest 60-day mortality was found in patients with widespread parenchymal abnormalities combined with pulmonary embolism (36%), followed by patients with widespread parenchymal abnormalities without pulmonary embolism (26%). In multivariate analysis, high troponin T, D-dimer, and plasma creatinine and widespread parenchymal abnormalities on CT were associated with 60-day mortality. Conclusions: Pulmonary embolism combined with widespread parenchymal abnormalities contributed to mortality risk in COVID-19. Elevated C-reactive protein, D-dimer, troponin-T, P-creatinine, and enlarged pulmonary artery were associated with a worse outcome and may mirror a more severe systemic disease. A liberal approach to radiological investigation should be recommended at clinical deterioration, when the situation allows it. Computed tomography imaging, even without intravenous contrast to assess the severity of pulmonary infiltrates, are of value to predict outcome in COVID-19. Better radiological techniques with higher resolution could potentially improve the detection of microthromboses. This could influence anticoagulant treatment strategies, preventing clinical detoriation.

New Algorithm for the Management of Orbital Blowout Fracture Based on Prospective Study.

Despite extensive debate and publications in the management of blowout fracture (BOF), there are still considerable differences in the surgeons' management of BOF due to a lack of reliable evidence-based studies. This article aimed to evaluate which BOF patients require surgical treatment due to functional and/or cosmetic deformities; evaluate which computed tomography (CT) scan findings predict these problems; and provide an algorithm in the management of BOF. Seventy-nine patients with BOF were treated conservatively and followed up prospectively regarding functional and cosmetic deformities for at least 1 year. The patients' CT scans were analyzed and several measurements were performed. Patients' symptoms and the clinical findings were correlated to the CT scan measurements. We found visible deformity in 37% of the patients, but only 10% chose to proceed to surgery due to cosmetic deformities. In patients with inferior BOF and a herniation < 1.0 mL, a visible deformity was found when the ratio between fracture and the fractured orbital wall areas was ≥42%, or the total area of the fracture was ≥ 2.3 cm 2 . In patients with inferior BOF and a herniation ≥ 1.0 mL, a visible deformity was found when the distance from the inferior orbital rim to the posterior edge of the fracture was ≥ 3.0 cm. In patients with inferomedial fracture, a visible deformity was found when the herniation was ≥ 0.9 mL. Diplopia improved significantly and remained in only 3% of the patients in nonoperated group. Hypoesthesia of the infraorbital nerve improved significantly, but 23% of the nonoperated and 50% of the operated patients still experienced loss of sensation at final control. In this prospective study, we found that not only herniated orbital volume but also other CT scan findings in BOF were crucial to predict late visible deformities. Based on these findings, we propose an algorithm for the prediction of late visible deformity with 83% accuracy. There are indications that diplopia without ocular motility disorder is due to edema and we recommend observation as long as the diplopia improves gradually.

Anatomic distribution of hematoma following pelvic fracture.

OBJECTIVE: To assess the extent of pelvic hemorrhage on CT and to estimate its significance on outcome in patients with blunt high-energy pelvic trauma. METHODS: 576 patients with blunt high-energy pelvic fractures in 2005-2011 were identified in the hospital's Trauma Registry (a major Trauma Center). 60 of these met our further inclusion criteria of initial systolic blood pressure ≤100 mmHg and pelvic-related hemorrhage. CT scans of the patients were reviewed with regard to pelvic and abdominal retroperitoneal hemorrhage, type of fracture (Tile classification) and associated injuries. Extent of hemorrhage was correlated to 30-day mortality, transfusion requirements and need of angiography. Statistical methods include Pearson's Χ2 test and Fisher's exact test. RESULTS: Pelvic hemorrhage extended beyond the pelvis to the abdominal area in 47% of the patients, to the thighs in 25% and to the gluteal areas in 81%. The extent of hemorrhage was significantly associated with the need for blood transfusions (p = 0.011) and angiography (p < 0.001), but not with 30-day mortality. CONCLUSION: Traumatic pelvic bleeding frequently extends beyond the true pelvis. Extrapelvic hemorrhage correlates with an increased need of transfusions, but not with 30-day mortality. Further studies are needed to assess whether present techniques to control pelvic bleeding need to be modified in order to further reduce mortality in traumatic pelvic hemorrhage. Advances in knowledge: The study shows localization of pelvic hemorrhage in trauma patients. It may help to select patients in need of further interventions to control bleeding.

Three-dimensional computed tomography planning improves percutaneous stone surgery.

OBJECTIVE: Percutaneous nephrolithotripsy (PCNL) has become the gold standard for treatment of renal stones larger than 2 cm. To optimize the surgical procedure a method for meticulous preoperative three-dimensional computed tomography (3D-CT) planning was developed and analysed. The aim of this study was to evaluate how 3D-CT influenced the choice of access route and treatment outcome. MATERIAL AND METHODS: Patients planned for PCNL were included in a prospective study. Decision algorithms were studied and recorded before and after 3D-CT planning in a total of 35 patients. RESULTS: Thirty-one of the patients (88%) had a complex stone situation. The CT examinations resulted in change of access plan in 15 out of 28 patients, in addition to seven patients where access could not be planned without 3D-CT, totalling 22 out of 35 (63%). This resulted in 24 patients (69%) being stone free after a single PCNL session. Of these 24 patients, 22 (22/35 = 63%) were stone free with one dilated access track only. In 16 of the 24 patients (76%) who were stone free after one PCNL procedure, evaluation of the 3D-CT images had changed the initial preoperative planning (10 cases) or made planning possible (six cases). A few patients had thoracic complications but there were no cases with bleeding. CONCLUSIONS: Preoperative planning of complex stone situations with 3D-CT had a significant impact on operative procedure, resulting in a low number of access punctures.

Variation in calvarial bone healing capacity: a clinical study on the effects of BMP-2-hydrogel or bone autograft treatments at different cranial locations.

BACKGROUND: Bone morphogenetic protein-2 (BMP-2) together with a suitable carrier is an attractive option that may be used for craniofacial bone reconstruction. In this prospective randomized study, a hyaluronan-based hydrogel with BMP-2 was used to achieve bone healing in standardized critical-size cranial defects in humans after neurosurgery. METHODS: Twelve patients were randomized into the treatment group (N = 6) or control group (N = 6). In the treatment group, holes made during craniotomy were treated with hydrogel with BMP-2, 250 µg/mL, or hydrogel without BMP-2. In the remaining hole/s in the same patient, Spongostan (Ethicon) alone or Tisseel (Baxter) mixed with autologous bone matrix were used as negative and positive controls, respectively. In the control group, the holes were treated with Spongostan or Tisseel mixed with bone autograft. Bone healing was assessed with CT scans after 3 and 6 months. Bone areas in treated defects were measured and statistical analysis was performed. RESULTS: Independent of location, bone healing in defects treated with Tisseel with autograft, hydrogel alone, or hydrogel with BMP-2 was significantly increased compared to negative control (P < 0.001, P = 0.002, and P = 0.005, respectively). In general, all defects healed significantly better in the frontal bone as compared to parietal-temporal location, except for defects treated with Tisseel and autograft, which healed well independently of location. No local or systemic side effects, including excessive bone overgrowth or inflammatory reaction, were seen in treated patients. CONCLUSIONS: Tissue engineering of bone with hyaluronan-based hydrogel shows good healing of cranial defects, comparable with bone autografts. The hydrogel itself may represent a novel alternative to autologous bone transplants in craniofacial bone repair. The study also reveals a general superior healing capacity in the frontal bone as compared to parietal/temporal bones.

Salvage of failed trochanteric and subtrochanteric fractures using a distally fixed, modular, uncemented hip revision stem.

BACKGROUND AND PURPOSE: Treatment options for failed internal fixation of hip fractures include prosthetic replacement. We evaluated survival, complications, and radiographic outcome in 30 patients who were operated with a specific modular, uncemented hip reconstruction prosthesis as a salvage procedure after failed treatment of trochanteric and subtrochanteric fractures. PATIENTS AND METHODS: We used data from the Swedish Hip Arthroplasty Register and journal files to analyze complications and survival. Initially, a high proportion of trochanteric fractures (7/10) were classified as unstable and 12 of 20 subtrochanteric fractures had an extension through the greater trochanter. Modes of failure after primary internal fixation were cutout (n = 12), migration of the femoral neck screw (n = 9), and other (n = 9). RESULTS: Mean age at the index operation with the modular prosthesis was 77 (52-93) years and the mean follow-up was 4 (1-9) years. Union of the remaining fracture fragments was observed in 26 hips, restoration of proximal bone defects in 16 hips, and bone ingrowth of the stem in 25 hips. Subsidence was evident in 4 cases. 1 patient was revised by component exchange because of recurrent dislocation, and another 6 patients were reoperated: 5 because of deep infections and 1 because of periprosthetic fracture. The cumulative 3-year survival for revision was 96% (95% CI: 89-100) and for any reoperation it was 83% (68-93). INTERPRETATION: The modular stem allowed fixation distal to the fracture system. Radiographic outcome was good. The rate of complications, however-especially infections-was high. We believe that preoperative laboratory screening for low-grade infection and synovial cultures could contribute to better treatment in some of these patients.

Accuracy of low-dose chest CT in intensive care patients.

In this prospective study, we set out to determine the accuracy of low-dose computerized tomography (LDCT) of the chest in intensive care patients. Fifteen adult intensive care patients were examined with a standard-dose CT protocol (average radiation dose = 6.7 mSv), chosen as the reference standard, followed by a non-contrast-enhanced LDCT protocol (average radiation dose = 0.59 mSv). Each examination was then read by two separate groups of radiologists blinded to both the purpose and the protocol of the study. In the small group examined, the results showed 100% accuracy in the diagnosis of pneumomediastinum, pericardial effusion, and pleural effusion, and 90% accuracy in the diagnosis of pneumothorax and consolidation. There were no false-positive findings, and the few false-negative findings were unlikely to lead to any clinical interventions. Our examination protocol, while providing a tenfold reduction of the radiation dose, nevertheless remained accurate enough for resolving certain clinical questions common in the intensive care patient. Thus, we suggest that protocols aimed at reducing the radiation dose in chest CT could be applied to the intensive care patient for resolving some specific questions, without compromising the diagnostic yield of the examinations.

Minimum 5-year follow-up of a cementless, modular, tapered stem in hip revision arthroplasty.

Hip revision surgery with a cementless tapered femoral component can provide axial and rotational stability in patients with compromised proximal bone stock. This study includes 90 cases revised with the Link MP (Waldemar Link, Hamburg, Germany) prosthesis. The median age at surgery was 72 (38-89) years. Aseptic loosening (70%) and periprosthetic fracture (22%) were common indications for surgery. Sixty-three patients (70%) were followed clinically with a median of 6 (5-11) years of follow-up. All other patients were followed through the Swedish Hip Register. The 5-year survival rate was 98% with stem removal and 90% with any reoperation as the end point. Complications included hip dislocation in 17 (19%) patients. The median Harris hip score was 78 (16-100) points, and the median radiographic stem migration was 2.7 mm at follow-up.

Relative difference in orbital volume as an indication for surgical reconstruction in isolated orbital floor fractures.

In orbital floor fractures, the estimation of the herniated orbital content in the maxillary sinus has traditionally been the dividing line between surgical and nonsurgical management. In this study, we evaluated whether a relative change in volume would function as an indicator for surgical versus nonsurgical treatment of orbital floor fractures. This was a follow-up study in patients with untreated unilateral isolated orbital floor fractures admitted to our department from March 2003 to April 2007. Patients were contacted by regular mail and invited to have a clinical eye examination. The volume of the orbital content was calculated digitally from the patients' computed tomography scans at the time of their injury. Eighteen subjects with no facial skeleton fracture were included for reference of orbital content volumes. Five of 23 patients showed 2 to 4 mm of enophthalmos, and only three of them had intermittent diplopia. No statistical correlation was found between the herniated volume and enophthalmos. No statistical correlation supporting the supposition that 1 mL of herniated orbital content would result in 1 mm of enophthalmos was found. The relative volume change between the fractured and nonfractured orbit in an individual does not appear to be a useful criterion for surgery. The importance of the herniated orbital tissue for the development of enophthalmos is unclear.

Distal femoral stem-bone anchorage of a cementless revision total hip arthroplasty: evaluation of 14 patients by CT.

BACKGROUND AND PURPOSE: According to the manual of the cementless Link MP reconstruction prosthesis, a distal femoral stem-bone anchorage of at least 80 mm is necessary to gain implant stability. There have been no in vivo studies showing that this distance is either achieved in clinical practice or needed for clinically satisfying results. Thus, we assessed the femoral stem-bone anchorage of the MP prosthesis using CT. METHODS: 14 patients with the MP stem were evaluated by CT scans at a median follow-up time of 12 months postoperatively. Femoral stem-bone anchorage was defined as adequate if 50% of the stem flutes or more had cortical bone contact. The length of anchorage was derived from the number of slices with adequate anchorage. Clinical outcome was assessed with VAS for pain and Harris hip score (HHS), both at 1 and 5 years of follow-up. RESULTS: The median length of stem-bone anchorage was 33 mm (interquartile range 10-60), which was shorter than recommended (p = 0.002). Still, at the 1-year control, all patients were fully weight-bearing and only 1/14 complained about mild thigh pain. 7/14 patients did not experience any pain in the affected hip. The patients had a median of 85 points in the HHS. The clinical outcome at 5 years was unchanged. INTERPRETATION: We found that it can be difficult to achieve a stem-bone anchorage of at least 80 mm for the MP Link prosthesis. However, this does not appear to be necessary to obtain stability and to achieve clinically satisfying results.

Bleeding into the intraluminal thrombus in abdominal aortic aneurysms is associated with rupture.

OBJECTIVE: The aim of this study was to determine signs of bleeding in the intraluminal thrombus and the site of rupture using multislice computed tomography (CT) imaging in patients with abdominal aortic aneurysms (AAA). METHODS: We analyzed CT images of 42 patients with ruptured infrarenal AAA in two hospitals in Stockholm, Sweden during a 3-year period. A "crescent sign" or localized areas with higher attenuation in the thrombus were interpreted as signs of bleeding in the thrombus. A localized area of hyperattenuation did not have the typical crescent shape and was distinguished from calcifications in the thrombus. We measured the attenuation in Hounsfield units in the intraluminal thrombus using CT software to quantify the presence of blood in the thrombus. As controls, we analyzed 36 patients with intact AAA and a comparable aneurysm diameter and age. RESULTS: The crescent sign was more frequent in the ruptured group (38% vs 14%, P = .02), but there was no significant difference in the presence of localized areas of hyperattenuation in the two groups. The attenuation in the thrombus was significantly higher in patients with rupture than in those with intact aneurysms (P = .02). The site of rupture could be localized in 29/42 patients. Ruptures occurred both through the thrombus-covered and the thrombus free wall. In 45% of the patients, the rupture site was localized in the left lateral wall, in 24% in the anterior wall, in 24% in the right lateral wall, but only in 7% in the posterior wall. CONCLUSION: The site of rupture could be identified in a majority of cases of AAA with routine multislice CT. This study demonstrates an association between the presence of blood in the thrombus as suggested by higher attenuation levels and a crescent sign and AAA rupture. If these findings also predict AAA rupture, remains to be established.

A new CT method for measuring cup orientation after total hip arthroplasty: a study of 10 patients.

BACKGROUND: It is difficult to assess the orientation of the acetabular component on routine radiographs. We present a method for determining the spatial orientation of the acetabular component after total hip arthroplasty (THA) using computed tomography. PATIENTS AND METHODS: Two CT-scans, 10 min apart, were obtained from each of 10 patients after THA. Using locally developed software, two independent examiners measured the orientation of the acetabular component in relation to the pelvis. The measurements were repeated after one week. To be independent of the patient position during scanning, the method involved two steps. Firstly, a 3D volumetric image of the pelvis was brought into a standard pelvic orientation, then the orientation of the acetabular component was measured. The orientation of the acetabular component was expressed as operative anteversion and inclination relative to an internal pelvic reference coordinate system. To evaluate precision, we compared measurements across pairs of CT volumes between observers and trials. RESULTS: Mean absolute interobserver angle error was 2.3 degrees for anteversion (range 0-6.6 degrees), and 1.1 degrees for inclination (range 0-4.6 degrees). For interobserver measurements, the precision, defined as one standard deviation, was 2.9 degrees for anteversion, and 1.5 degrees for inclination. A Student's t-test showed that the overall differences between the examiners, trials, and cases were not significant. Data were normally distributed and were not dependent on examiner or trial. INTERPRETATION: We conclude that the implant angles of the acetabular component in relation to the pelvis could be detected repeatedly using CT, independently of patient positioning.