The halo sign and peripancreatic fluid: useful CT signs of hypovolaemic shock complex in adults

ACR Appropriateness Criteria® Abnormal Liver Function Tests

Liver function tests are commonly obtained in symptomatic and asymptomatic patients. Various overlapping lab patterns can be seen due to derangement of hepatocytes and bile ducts function. Imaging tests are pursued to identify underlying etiology and guide management based on the lab results. Liver function tests may reveal mild, moderate, or severe hepatocellular predominance and can be seen in alcoholic and nonalcoholic liver disease, acute hepatitis, and acute liver injury due to other causes. Cholestatic pattern with elevated alkaline phosphatase with or without elevated γ-glutamyl transpeptidase can be seen with various causes of obstructive biliopathy. Acute or subacute cholestasis with conjugated or unconjugated hyperbilirubinemia can be seen due to prehepatic, intrahepatic, or posthepatic causes. We discuss the initial and complementary imaging modalities to be used in clinical scenarios presenting with abnormal liver function tests. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

CT signs of hypovolemic shock complex in patients with non-traumatic shock

PURPOSE

To assess the frequency of hypovolemic shock complex (HSC) signs on CT in patients who presented to the emergency department (ED) with undifferentiated non-traumatic shock. Secondary aim was to assess the correlation between HSC signs and all-cause mortality.

METHODS

This retrospective, single-center study included 100 patients who underwent contrast-enhanced thoraco-abdominal CT in the ED to evaluate the etiology for non-traumatic undifferentiated shock. All patients were retrospectively assigned a shock subtype (i.e., distributive, cardiogenic, hypovolemic, obstructive, multifactorial, and unknown) based on medical records. Patients' demographics and time to all-cause mortality up to 90 days were collected. All CT studies were re-assessed for the presence of HSC signs. Correlation between HSC signs, mortality and shock subtype was assessed.

RESULTS

Overall, 58% (58/100) of all patients had at least one HSC sign. Flattened inferior vena cava and adrenal hyper-enhancement were the most common HSC signs (27.3%, 27/99; in both). Overall mortality was 59% (59/100). When evaluated separately, shock liver was the only HSC sign to significantly correlate with increased mortality (84.6% vs. 55.2%, p = .04). However, patients with at least two HSC signs had a significantly higher mortality rate compared to patients without any HSC signs (73.5% vs. 45.2%, p = .017).

CONCLUSION

Most patients with non-traumatic shock had at least one HSC sign. Mortality rates were significantly higher in patients with two or more HSC signs compared to patients without any signs. Patients with shock liver sign had significantly higher mortality rates.

CT of Penetrating Abdominopelvic Trauma

Penetrating abdominopelvic trauma usually results from abdominal cavity violation from a firearm injury or a stab wound and is a leading cause of morbidity and mortality from traumatic injuries. Penetrating trauma can have subtle or complex imaging findings, posing a diagnostic challenge for radiologists. Contrast-enhanced CT is the modality of choice for evaluating penetrating injuries, with good sensitivity and specificity for solid-organ and hollow viscus injuries. Familiarity with the projectile kinetics of penetrating injuries is an important skill set for radiologists and aids in the diagnosis of both overt and subtle injuries. CT trajectography is a useful tool in CT interpretation that allows the identification of subtle injuries from the transfer of kinetic injury from the projectile to surrounding tissue. In CT trajectography, after the entry and exit wounds are delineated, the two points can be connected by placing cross-cursors and swiveling the cut planes obliquely in orthogonal planes to obtain a double-oblique orientation to visualize the wound track in profile. The path of the projectile and its ensuing damage is not always straight, and the imaging characteristics of free fluid of different attenuation in the abdomen (including hemoperitoneum) can support the diagnosis of visceral and vascular injuries. In addition, CT is increasingly used for evaluation of patients after damage control surgery and helps guide the management of injuries that were overlooked at surgery. An invited commentary by Paes and Munera is available online. Online supplemental material is available for this article. ©RSNA, 2021.

Computed tomography imaging of septic shock. Beyond the cause: the "CT hypoperfusion complex". A pictorial essay

Septic shock is a medical emergency that represents one of the most important underlying causes for presentation to the Emergency Department. Sepsis is defined as organ dysfunction, life-threatening event caused by a deregulated inflammatory host response to infection, with a mortality risk ranging from 10 to 40%. Early sepsis identification is the cornerstone of management and diagnostic imaging can play a pivotal role in this clinical context. The choice of imaging modality depends on several factors, associated with the clinical condition and the presence or absence of localising signs and symptoms. The diagnostic accuracy of contrast-enhanced total-body CT has been well established during septic shock, allowing for a rapid, panoramic, and detailed study of multiple body areas, simultaneously. The aim of this article is to illustrate the controversial CT hypoperfusion complex in patients with septic shock, characterised by the following imaging features: decreased enhancement of the viscera; increased mucosal enhancement; luminal dilation of the small bowel; mural thickening and fluid-filled loops of the small bowel; the halo sign and flattening of the inferior vena cava; reduced aortic diameter; peripancreatic oedema; abnormal parenchymal perfusion; and other controversial findings that are variably associated with each other and reversible during the early stages. Increasing physicians' awareness of the significance of these findings could prompt alternative approaches to the early assessment and management of septic shock. In this perspective, CT imaging represents a useful tool for a complete, rapid and detailed diagnosis of clinically suspected septic shock, which can be used to improve patient outcomes.

Bilateral adrenal enhancement revised-adrenal-to-spleen ratio as an appropriate mortality predictor

Purpose

To investigate whether adrenal gland radiodensities alone or set in relation to either the inferior vena cava (IVC) or the spleen can predict hospital mortality in intensive care unit patients.

Methods

One hundred thirty-three intensive care patients (90 males, age: 66.3 ± 14.5 years) with an acute clinical deterioration were included in this retrospective analysis. CT attenuation (Hounsfield units) of adrenal glands, IVC, and spleen was evaluated by 2 radiologists separately. Adrenal-to-IVC and adrenal-to-spleen ratios were calculated. Receiver operating characteristic (ROC) analysis, combined with the Matthews correlation coefficient (MCC) as a classifier, was used to assess which parameter is the most suitable for short-term, intermediate-term, and overall mortality prediction. Interrater agreement was assessed using intraclass correlation coefficient (ICC).

Results

The highest discriminative power to distinguish between deceased and survivors was found for the adrenal gland-to-spleen ratio for the 72-h mortality. A threshold of > 1.4 predicted 72-h mortality with a sensitivity of 79.31% and a specificity of 98.08% (area und the curve (AUC) = 0.94; p < 0.0001; MCCs = 0.81). The positive likelihood ratio was 41; the positive predictive value was 92.20%. Adrenal gland-to-spleen ratio was also best suited to predict the 24-h and overall mortality. ICCs of HU measurements in adrenal gland, IVC, and spleen indicated a high interrater agreement (ICC 0.95–0.99).

Conclusions

To conclude, the adrenal-to-spleen ratio in CT in portal venous phase may serve as an imaged-based predictor for short, intermediate, and overall mortality and as reproducible prognostic marker for patient outcome.

Shock Thyroid in a Patient with Septic Shock: A Case Report and Literature Review

Shock thyroid is a rare manifestation of the CT hypotension complex and can be diagnosed when thyroid and perithyroidal edemas are observed on CT during the onset of shock. Shock thyroid can be a useful CT sign for decompensated shock. This condition is reversible and recovers rapidly with adequate treatment. We present the case of an 84-year-old female with septic shock, exhibiting CT features consistent with a shock thyroid. We also reviewed the clinical and radiological findings reported in the literature. The present case emphasizes that shock thyroid can be an early indicator of impending hemodynamic instability and has important prognostic and therapeutic implications.

Vascular changes of the superior mesenteric artery (SMA): A new component of the hypovolemic shock complex (HSC)

PURPOSE

To assess the type and frequency of vascular changes in the superior mesenteric artery (SMA) associated with the hypovolemic shock complex (HSC).

METHODS

Twenty-six patients (14 males, 70.6 ± 11.2 years) meeting the criteria for hypovolemic shock complex in computed tomography were examined for the presence of angiographic signs of non-occlusive mesenteric ischemia (NOMI) in the SMA: the string of sausages sign and spasms of the arcades of mesenteric arteries on coronal maximum intensity projection images (MIP). Interrater agreement was assessed using weighted kappa (κ).

RESULTS

Vascular changes of the SMA were visible in almost all of the patients with HSC with a frequency of 88.5 %-96.2 %. Intraclass correlation coefficients indicated a substantial to almost perfect interrater agreement.

CONCLUSIONS

Using computed tomography, it is possible to reliably and reproducibly detect vascular changes in SMA known from angiography in the context of hypoperfusion. The pathological vascular changes also occur more frequently than other classic signs of a CT hypoperfusion complex. Since the qualitative assessment of the SMA requires only a small amount of time, it is suitable as a further criterion for the presence of the CT hypoperfusion complex.

Adrenal glands enhancement in computed tomography as predictor of short-and intermediate term mortality in critically ill patients

PURPOSE

To investigate whether adrenal gland radiodensities alone or compared to the inferior vena cava (IVC) can correctly predict hospital mortality in patients in intensive care.

METHODS

One hundred thirteen intensive care patients (76 males, age: 67.2 ± 14.0 years) with an acute clinical deterioration were included in this retrospective analysis. For the venous and the arterial phase CT attenuation (Hounsfield units) of adrenal glands and IVC was ROI-based evaluated by two radiologists separately. ROC analysis, combined with the Matthews Correlation Coefficient (MCC) as a classifier, was used to assess whether one of the parameters is suitable for predicting short and medium-term mortality and, if so, which parameter is most appropriate. Interrater agreement was assessed using the intraclass correlation coefficient.

RESULTS

Twenty-one patients (18.6%) died within three days in the ICU. Measurements of the adrenal glands in the portal venous phase yielded the highest discriminative power (=AUC) to distinguish between deceased and survivors. A threshold ratio of >95.5 predicted 72-hour mortality with a sensitivity of 76.19% and a specificity of 92.39% (AUC = 0.84; p < 0.0001). The positive likelihood ratio was 10.1; the positive predictive value was 69%. The predictive power for 24-hour mortality was slightly lower. Venous adrenal-to-IVC ratios and arterial measurements as a whole were substantially less suitable. All intraclass correlation coefficients indicated a high interrater agreement.

CONCLUSIONS

In the portal venous phase, hyperattenuating of the adrenal glands on contrast-enhanced CT can predict short and intermediate ICU mortality quite well and may serve as a reproducible prognostic marker for individual patient outcomes.

Multidetector CT Findings in the Abdomen and Pelvis after Damage Control Surgery for Acute Traumatic Injuries

After experiencing blunt or penetrating trauma, patients in unstable condition who are more likely to die of uncorrected shock than of incomplete injury repairs undergo emergency limited exploratory laparotomy, which is also known as damage control surgery (DCS). This surgery is part of a series of resuscitation steps, with the goal of stabilizing the patient's condition, with rapid surgical control of hemorrhage followed by supportive measures in the intensive care unit before definitive repair of injuries. These patients often are imaged with multidetector CT within 24-48 hours of the initial surgery. Knowledge of this treatment plan is critical to CT interpretation, because there are anatomic derangements and foreign bodies that would not be present in patients undergoing surgery for other reasons. Patients may have injuries beyond the surgical field that are only identified at imaging, which can alter the care plan. Abnormalities related to the resuscitation period such as the CT hypoperfusion complex and ongoing hemorrhage can be recognized at CT. Familiarity with these imaging and clinical findings is important, because they can be seen not only in trauma patients after DCS but also in other patients in the critical care setting. The interpretation of imaging studies can be helped by an understanding of the diagnostic challenges of grading organ injuries with surgical materials in place and the awareness of potential artifacts on images in these patients. Online supplemental material is available for this article. ^©RSNA, 2019 See discussion on this article by LeBedis .

Hepatic Heterogeneity and Attenuation on Contrast-Enhanced CT in Patients With the Hypovolemic Shock Complex: Objective Classification Using a Contemporary Cohort

OBJECTIVE

When objectively measured on computed tomography (CT), does hepatic heterogeneity or overall liver attenuation predict the presence of shock?

METHODS

This retrospective study included 73 patients (mean age 33 years) with the hypoperfusion shock complex (HSC) on CT (cases) and 100 patients (mean age 43 years) with negative trauma CT scans (controls). Liver heterogeneity was calculated by using consistently sized regions of interest (ROIs) to measure the 2 highest and the 2 lowest areas of hepatic density (in Hounsfield units [HU]). The difference between the means of the 2 highest and 2 lowest ROIs was considered the heterogeneity. Attenuation was calculated using the mean of 3 randomly placed ROIs. Both heterogeneity and attenuation were then compared between cases and controls.

RESULTS

Median hepatic heterogeneity was 16.8 HU (IQR: 10.7-23.4) for the HSC group and 9.0 HU (IQR: 7.0-10.4) for the controls (P < 0.001). The area under the curve was 0.79, and a threshold of 30 HU yielded a specificity of 100%. Median hepatic attenuation was not significantly different between the HSC and the control groups, with an area under the curve of 0.56.

CONCLUSIONS

Increased hepatic heterogeneity may represent an objective marker of the HSC that performs in a similar manner to other established signs. By comparison, overall hepatic hypoattenuation is a poor indicator of the HSC.

Splenic contraction: a new member of the hypovolemic shock complex

OBJECTIVE

The objective of the article is to assess changes in splenic volume in the setting of hypovolemic shock; splenic enhancement in hypovolemic shock is also assessed.

MATERIALS/METHODS

71 consecutive adult patients with the hypovolemic shock complex on computed tomography (CT) were identified. Spleen volume and enhancement were compared to a baseline CT scan (without shock) or to height- and sex-corrected normal values and a control population when a comparison CT was unavailable.

RESULTS

Splenic volume was significantly lower in the setting of shock. Average splenic volume in adult patients with shock was 107 ± 63 cm³ compared to 220 ± 164 cm³ in the control population (P < 0.001). All shock patients with a comparison CT (n = 35) had decreased splenic volume in the setting of shock. The area under the receiver operating characteristic (ROC) curve for spleen volume predicting shock was 0.83. Splenic enhancement was also significantly lower in the setting of shock. Mean splenic attenuation value in our shock population was 105 ± 34 HU compared to 134 ± 25 HU in the control population (P < 0.001). Decreased splenic enhancement was present in 25 of 71 shock patients and in none of the control patients (P < 0.001).

CONCLUSION

Decreased splenic volume is a ubiquitous and reliable sign of hypovolemic shock and should be considered a member of the hypovolemic shock complex. It is of particular utility when a prior study is available. Splenic hypoenhancement has high specificity and a high positive predictive value for hypovolemic shock in the correct patient population.

Peritoneal fluid of low CT Hounsfield units as a screening criterion for traumatic bowel perforation

PURPOSE

To investigate whether peritoneal fluid of low CT Hounsfield units is an important screening criterion for traumatic bowel perforation.

MATERIALS AND METHODS

We performed a retrospective study on two cohorts of blunt trauma patients who had peritoneal fluid. Intravenous and oral contrast was used for the first cohort (61 patients) as opposed to intravenous contrast only for the second cohort (60 patients). We compared the CT Hounsfield units of peritoneal fluid with bowel perforation. The optimal cutoff value of CT Hounsfield units was determined, and its diagnostic values for bowel perforation were calculated.

RESULTS

The mean CT Hounsfield units (HU) of peritoneal fluid with bowel perforation were significantly lower (30.3 ± 9.0 versus 44.1 ± 13.6 HU, p = 0.008) in the second cohort. The optimal cutoff value was 43 HU, and its sensitivity, specificity, accuracy and positive likelihood ratio were 100.0, 69.2, 73.3% and 3.3, respectively, for bowel perforation. Comparisons of CT HUs of peritoneal fluid with bowel perforation in the first cohort that used additional oral contrast for CT did not show statistically significant differences.

CONCLUSION

Peritoneal fluid of low CT HU is a sensitive and important CT screening criterion for traumatic bowel perforation.

Remarkable CT features of shock thyroid in traumatic and non-traumatic patients

Shock thyroid is a part of the hypovolemic shock complex, which is a constellation of secondary computed tomographic (CT) findings that are observed in patients with hypovolemic shock. However, to the best of our knowledge, there has only been a single report on this condition, which described three cases associated with significant thoracoabdominal trauma. Here, we report four patients with profound hypotension who exhibited similar CT findings as those described in the initial report on shock thyroid, but with a more diverse clinical spectrum.

Contrast-Enhanced Computed Tomography in Intensive Care Unit Patients With Acute Clinical Deterioration: Impact of Hyperattenuating Adrenal Glands

PURPOSE

The study sought to assess the frequency and prognostic value of hyperattenuating adrenal glands on contrast-enhanced computed tomography (CT) scans of surgical intensive care unit (ICU) patients with acute clinical deterioration.

METHODS

Eighty-eight consecutive ICU patients (63.2 ± 14.5 years of age) were included in this retrospective analysis. All patients underwent biphasic contrast-enhanced CT due to an acute clinical deterioration. Hyperattenuation of the adrenal glands was assessed subjectively and objectively. Subjective presence or absence of hyperattenuating adrenal glands was assessed by 2 blinded radiologists (J.B. and R.S.L.) in consensus. Hounsfield units (HU) were measured in the adrenal glands and in the inferior vena cava. Objective hyperattenuation was defined as HU (adrenal glands) > HU (inferior vena cava) with a 15-HU threshold. Death within 14 days following CT was set as endpoint and acquired from electronic patient data.

RESULTS

Thirty-eight patients (43.2%, Group A_subj) exhibited hyperattenuation of the adrenal glands, whereas 50 patients (56.8%, Group B_subj) did not. Concerning the objective analysis, 31 patients (35.2%, Group A_obj) exhibited hyperdense adrenal glands, whereas 53 patients (64.8%, Group B_obj) did not. Overall 27 of 88 patients (30.6%) died within 14 days following the CT examination. Lethal outcome was significantly more frequent among patients in Group A_subj and A_obj (19 of 38 patients [50.0%] and 15 of 31 patients [48.4%]) as compared with patients in Group B_subj (8 of 50 patients [16.0%]) and Group B_obj (12 of 57 patients [21.1%]; P < .05). Subjective and objective analysis correlated significantly (P < .05).

CONCLUSIONS

Hyperattenuation of adrenal glands on contrast-enhanced CT of ICU patients with acute clinical deterioration is associated with a high mortality and might serve as a prognostic marker for patients' outcome.

Intense Adrenal Enhancement: A CT Feature of Cardiogenic Shock

In this report, images of intense adrenal enhancement in a 79-year-old female patient with right-sided heart failure and severe tricuspid insufficiency are presented. Only two cases of intense adrenal enhancement as a sign of cardiogenic shock were previously reported in the literature. Intense adrenal enhancement could be one of the earliest CT signs of cardiogenic shock. Its presence should be immediately reported to the referring physician as a sign of significant hemodynamic instability warranting early critical-care management.

Pediatric nonaccidental abdominal trauma: what the radiologist should know

Abdominal injury in nonaccidental trauma (NAT) is an increasingly recognized cause of hospitalization in abused children. Abdominal injuries in NAT are often severe and have high rates of surgical intervention. Certain imaging findings in the pediatric abdomen, notably bowel perforation and pancreatic injury, should alert the radiologist to possible abuse and incite close interrogation concerning the reported mechanism of injury. Close inspection of the imaging study is warranted to detect additional injury sites because these injuries rarely occur in isolation. When abdominal injury is suspected in known or speculated NAT, computed tomography (CT) of the abdomen and pelvis with intravenous contrast material is recommended for diagnostic and forensic evaluation. Although the rate of bowel injury is disproportionately high in NAT, solid organs, including the liver, pancreas, and spleen, are most often injured. Adrenal and renal trauma is less frequent in NAT and is generally seen with multiple other injuries. Hypoperfusion complex is a constellation of abdominal CT findings that indicates current or impending decompensated shock and is most often due to severe neurologic impairment in NAT. Although abdominal injuries in NAT are relatively uncommon, knowledge of injury patterns and their imaging appearances is important for patient care and protection.

Traumatic hypovolemic shock revisited: the spectrum of contrast-enhanced abdominal computed tomography findings and clinical implications for its management

Hypovolemic shock is often seen in patients with severe blunt trauma who have suffered from blood circulation inadequate to maintain oxygen delivery to multiple organs. The early recognition and prompt management of hypovolemic shock in patients with multiple injuries are mandatory to improving prognosis and patient conditions. The diagnostic accuracy of computed tomography (CT) as a primary diagnostic tool is well established. The abdominal organs show several common and classic appearances on contrast-enhanced CT in patients with trauma. The hypovolemic shock complex is reported in the previous literature as decreased enhancement of the viscera, increased mucosal enhancement and luminal dilation of the small bowel, mural thickening and fluid-filled loops of the small bowel, the halo sign and flattening of the inferior vena cava, reduced aortic diameter, and peripancreatic edema. However, there have been controversial CT reports with contradictory appearances. Physicians understanding these findings could prompt alternative approaches to the early assessment and management of hypovolemic shock. The aim of this article is to illustrate common and well-known abdominal CT features in patients with traumatic hypovolemic shock, to discuss controversial CT signs in the pancreas and adrenal gland, and to describe CT findings' clinical implications when managing hypovolemic shock.

Pseudopancreatitis on computed tomography in a patient with isolated blunt head trauma: a case report

INTRODUCTION

Computed tomography is commonly used to exclude occult injuries in patients with trauma, but imaging can reveal findings that are of uncertain etiology or clinical significance. We present a case of unsuspected pancreatic abnormality in a female patient with trauma who sustained an isolated blunt head injury.

CASE PRESENTATION

A 25-year-old female Caucasian patient sustained massive blunt and penetrating head trauma, secondary to a large object penetrating through the vehicle windshield. Based on the mechanism of injury and clinical evaluation, it was felt to be an isolated head injury. However, computed tomography of her abdomen revealed an occult, intra-abdominal finding of significant pancreatic enlargement and peripancreatic fluid. There was no computed tomography evidence of parenchymal pancreatic laceration. The appearance of her pancreas on computed tomography was identical to that of acute pancreatitis or low-grade pancreatic injury, but her clinical history and laboratory values were not consistent with this, hence the term 'pseudopancreatitis'. Later surgery for organ donation confirmed diffuse pancreatic and peripancreatic edema, but no hematoma, contusion or other evidence for direct traumatic injury. This was an isolated intra-abdominal abnormality.

CONCLUSION

The routine use of computed tomography in patients who have sustained trauma has led to increasing detection of unexpected findings. Clinical information such as mechanism of injury and blood work, along with careful evaluation of ancillary imaging findings (or lack of), is important for the provision of an appropriate differential diagnosis. We discuss the possible mechanism and differential diagnosis of an isolated pancreatic abnormality in the setting of non-abdominal trauma, which includes shock pancreas, overhydration, traumatic pancreatic injury and pancreatitis secondary to other etiologies.

Hypovolemic shock complex: does the pancreatic perfusion increase or decrease at contrast-enhanced dynamic CT?

OBJECTIVE

The purpose of this study is to evaluate contrast enhancement effects of the pancreas at dynamic computed tomography (CT) to clarify whether pancreatic perfusion increases or decreases in severe trauma patients with hypovolemic shock.

METHODS

A total of 90 patients with (n=30) and without (n=60) blunt trauma and hypovolemic shock who underwent dynamic CT for abdomen was included. The measurement of CT attenuation values of the pancreas in the early phase and the late phase was performed to compare the contrast enhancement effects between patients with and without hypovolemic shock.

RESULTS

The mean CT attenuation values of the pancreas in the early phase of dynamic CT in patients with hypovolemic shock [95.4±29.1 Hounsfield units (HU)] were significantly lower (P < .001) than those in non-hypovolemic patients (136.6±17.9 HU), indicating decreased pancreatic perfusion in patients with hypovolemic shock. The mean CT attenuation values of the pancreas in the late phase of dynamic CT in patients with hypovolemic shock (95.9±17.6 HU) were significantly higher (P < .026) than those in non-hypovolemic patients (87.2±9.0 HU), indicating delayed or prolonged pancreatic enhancement in patients with hypovolemic shock.

CONCLUSIONS

Decreased pancreatic perfusion in the early phase and delayed pancreatic enhancement in the late phase of contrast-enhanced dynamic CT was a common finding in patients with hypovolemic shock.

Dynamic contrast-enhanced CT of the abdomen to predict clinical prognosis in patients with hypovolemic shock

OBJECTIVE

The objective of our study was to investigate the value of dynamic contrast-enhanced CT (DCE-CT) findings in predicting the clinical prognosis of patients with hypovolemic shock.

MATERIALS AND METHODS

This study included 33 patients with hypovolemic shock who underwent DCE-CT of the abdomen due to trauma. The CT attenuation values of several abdominal organs (spleen, liver, pancreas, kidneys [cortex and medulla], adrenal gland) in patients with hypovolemic shock were measured in the early phase and delayed phase to compare the differences in contrast enhancement effects between the survival group and the deceased group.

RESULTS

Among the 33 patients with hypovolemic shock, 15 patients died (deceased group) within 5 weeks (mean, 6 days). The remaining 18 patients survived and recovered (survival group). The mean CT attenuation values of the renal medulla in the delayed phase CT in the deceased group (155.4 ± 60.1 [SD] HU) were significantly lower (p = 0.001) than those in the survival group (227.3 ± 47.3 HU). The mean CT attenuation values of the renal medulla in the early phase CT did not show a significant difference between the two groups (102.4 ± 61.7 vs 113.9 ± 43.5 HU, respectively). The mean CT values of the spleen in the early phase CT in the deceased group (90.8 ± 26.0 HU) were significantly lower (p = 0.015) than those in the survival group (119.9 ± 33.9 HU). Regarding other CT measurements, there were no other significant differences between the deceased group and survival group.

CONCLUSION

Decreased enhancement of the renal medulla in the delayed phase and decreased enhancement of the spleen in the early phase are useful CT findings to predict a poor clinical prognosis in patients with hypovolemic shock.

Retrospective analysis of contrast-enhanced computed tomographic findings related to obstructive shock due to ascending aortic dissection

OBJECTIVE

The objective of this study was to evaluate contrastenhanced computed tomography findings related to obstructive shock due to ascending aortic dissection (AAD).

METHODS

The computed tomography findings in 9 AAD patients with shock, 11 AAD patients without shock, and 18 control subjects were evaluated for (1) pericardial effusion, (2) diameter of the inferior vena cava, (3) periportal hypodensity, (4) retrograde reflux of contrast material, (5) aortic and visceral enhancement, and (6) other factors (peripancreatic edema, bowel thickening/dilatation).

RESULTS

Patients with shock showed the highest ratio of pericardial effusion, periportal hypodensity, and retrograde reflux of contrast material; largest inferior vena cava diameter; stronger aortic enhancement in both the arterial and portal phases; lowered splenic and pancreatic enhancement in the arterial phase; and stronger visceral (especially adrenal) enhancement, except for the renal medulla in the portal phase.

CONCLUSIONS

Computed tomography findings related to obstructive shock due to AAD reflected impaired diastolic filling, decreased cardiac output, and flow redistribution in visceral organs.

Predictive value of a flat inferior vena cava on initial computed tomography for hemodynamic deterioration in patients with blunt torso trauma

BACKGROUND

We aimed to investigate the value of the diameter of the inferior vena cava (IVC) on initial computed tomography (CT) to predict hemodynamic deterioration in patients with blunt torso trauma.

METHODS

We reviewed the initial CT scans, taken after admission to emergency room (ER), of 114 patients with blunt torso trauma who were consecutively admitted during a 24-month period. We measured the maximal anteroposterior and transverse diameters of the IVC at the level of the renal vein. Flat vena cava (FVC) was defined as a maximal transverse to anteroposterior ratio of less than 4:1. According to the hemodynamic status, the patients were categorized into three groups. Patients with hemodynamic deterioration after the CT scans were defined as group D (n = 37). The other patients who remained hemodynamically stable after the CT scans were divided into two groups: patients who were hemodynamically stable on ER arrival were defined as group S (n = 60) and those who were in shock on ER arrival and responded to the fluid resuscitation were defined as group R (n = 17).

RESULTS

The anteroposterior diameter of the IVC in group D was significantly smaller than those in groups R and S (7.6 mm ± 4.4 mm, 15.8 mm ± 5.5 mm, and 15.3 mm ± 4.2 mm, respectively; p < 0.05). Of the 93 patients without FVC, 16 (17%) were in group D, 14 (15%) required blood transfusion, and 8 (9%) required intervention. However, of the 21 patients with FVC, all patients were in group D, 20 (95%) required blood transfusion, and 17 (80%) required intervention. The patients with FVC had higher mortality (52%) than the other patients (2%).

CONCLUSION

In cases of blunt torso trauma, patients with FVC on initial CT may exhibit hemodynamic deterioration, necessitating early blood transfusion and therapeutic intervention.

Pictorial review: computed tomography features of cardiovascular emergencies and associated imminent decompensation

Multi-detector computed tomography (MDCT) scanner is available in most hospitals and is increasingly being used as the first line imaging in trauma and suspected cardiovascular emergencies, such as acute coronary syndrome, pulmonary artery thrombo-embolism, abdominal aortic aneurysm and acute haemorrhage (Ryan et al. Clin Radiol 60:599-607, 2005). A significant number of these patients are haemodynamically unstable and can rapidly progress into shock and death. Recognition of computed tomography (CT) signs of imminent cardiovascular decompensation will alert the clinical radiologist to the presence of shock. In this review, the imaging findings of cardiovascular emergencies in both acute traumatic and non-traumatic settings with associated signs of imminent decompensation will be described and illustrated.

Pseudopancreatitis in trauma patients

OBJECTIVE

The purpose of our study was to review the significance of intra- and peripancreatic fluid in trauma patients who have no other signs of pancreatic injury.

CONCLUSION

We propose that intra- and peripancreatic fluid may be the consequence of hypovolemic shock treated with hyperhydration when there is significant delay between injury and imaging.

CT hypotension complex (shock bowel) is not always due to traumatic hypovolemic shock

OBJECTIVE

The purpose of our study was to review the clinical and CT findings in a substantial series of 41 patients with the shock bowel sign to determine if there is an association between shock bowel (and other CT signs of hypotension) and conditions other than post-traumatic hypovolemic shock.

CONCLUSION

The shock bowel sign and the CT hypotension complex are frequently associated with hypotension from causes other than trauma-induced hypovolemic shock, such as severe head or spine injury, cardiac arrest, septic shock, bacterial endocarditis, and diabetic ketoacidosis. Other elements of the CT hypotension complex such as flattening of the inferior vena cava and aorta, abnormal pancreatic enhancement and peripancreatic fluid, and hypoperfusion of the spleen and liver are variably associated with shock bowel whether due to posttraumatic hypovolemia or other causes of hypotension. The CT hypotension complex (shock bowel) has important prognostic and therapeutic implications and can probably be distinguished from bowel trauma and other forms of bowel injury in most cases.

Traumatic Retroperitoneal Injuries: Review of Multidetector CT Findings

Multidetector computed tomography (CT) represents a significant advance in CT technology and can allow the accurate assessment of trauma patients, including the detection of traumatic retroperitoneal injuries, many of which are clinically occult. Retroperitoneal injuries include duodenal, pancreatic, vascular, renal, and adrenal injuries. Abnormal blood, fluid, or air within the retroperitoneal spaces may be isolated findings but can also occur in association with these injuries, and their recognition is the key to correctly identifying the injury. Accurate characterization of injury with CT can affect clinical management and can help minimize unnecessary laparotomies. Equivocal findings at initial abdominal CT should prompt close clinical follow-up with possible imaging follow-up, particularly for suspected occult duodenal and pancreatic injuries.

A pictorial review of hypovolaemic shock in adults

Hypovolaemic shock is an infrequently encountered entity found on CT of victims of severe trauma. Early abdominal and pelvic CT can show diffuse abnormalities owing to hypovolaemia that may alert radiologists to the presence of hypovolaemic shock. In this pictorial review, we present the imaging findings of hypovolaemic shock, as seen on CT of the abdomen. A spectrum of vascular and visceral CT signs is described. Vascular signs include diminished inferior vena cava diameter, diminished aortic diameter and abnormal vascular enhancement. Hollow visceral abnormalities include diffuse increased mucosal enhancement of both the small and large bowel, diffuse thickening of the small bowel wall, and small bowel dilatation. Solid visceral abnormalities include both decreased and increased end organ enhancement. This report should increase radiologists' awareness of the CT manifestations of hypovolaemic shock.

CT evaluation of shock viscera: a pictorial review

The purpose of this article is to review both the pathophysiology and the computed tomography features of the hypoperfusion complex and shock viscera. The main findings include dilated fluid-filled loops of bowel with hyperenhancing mucosa, intensely enhancing kidneys and mesenteric vasculature, and small caliber, dense aorta and collapsed, slit-like inferior vena cava. Variable features include increased enhancement of the adrenals, decreased enhancement of the spleen, and altered enhancement of the pancreas with both hypo- and hyperenhancement described. This complex of findings indicates a tenuous hemodynamic status and has been associated with a poor prognosis. In addition, it is important to discern this collection of findings from direct injury to the viscera to aid in appropriate triage and management of the patients' injuries.

Blunt abdominal trauma: current imaging techniques and CT findings in patients with solid organ, bowel, and mesenteric injury

Imaging plays a critical role in the evaluation of patients with blunt abdominal trauma. In most institutions, computed tomography (CT) is the modality of choice when evaluating such patients. The purpose of this review is to highlight current techniques in trauma imaging and to review CT findings associated with solid organ, bowel, mesenteric, and diaphragmatic injury. In particular, emphasis is placed on the use of multidetector CT technology (MDCT), especially 64-row detector CT. The role of various techniques, including the use of oral and intravenous contrast, as well as the potential benefit of delayed imaging, is discussed.

Intense adrenal enhancement in patients with acute pancreatitis and early organ failure

Intense adrenal enhancement has previously been reported in patients with hypovolemic and septic shock. The purpose of this study was to assess whether this computed tomography (CT) finding is also observed in patients presenting with severe acute pancreatitis and early organ failure. A retrospective analysis of a prospectively collected database was performed. Out of 38 consecutive patients with predicted severe acute pancreatitis, 3 patients showed intense bilateral adrenal enhancement on early CT. All patients had early multiple organ failure and subsequently died. In two cases, pathologic correlation was obtained. Intense adrenal enhancement may be a new prognostic indicator in patients with acute pancreatitis, particularly when organ failure is present at the time of CT examination. Further studies are necessary to confirm this observation.