CT of hemorrhagic complications of anticoagulant therapy

Gastrointestinal intramural hematoma--analysis of clinical and radiological features for early differentiation from mesenteric ischemia

INTRODUCTION

Long-term anticoagulation is associated with hemorrhage at various sites. Gastrointestinal intramural bleeds and hematomas (IMH) often mimic mesenteric ischemia (MI) due to similar clinical settings and imaging features, making early differentiation difficult.

AIM

To compare the demography, clinical features and imaging characteristics of patients presenting with IMH with those of MI, so as to help in evolving clinical and imaging guidelines to differentiate both early in the course of the disease.

METHODS

All radiologically (contrast-enhanced computed tomogram [CT]) diagnosed cases of gastrointestinal IMH from the hospital database during the period between 2006 and 2012 were retrospectively analyzed. This data was compared with the clinical and imaging features of a group of surgically confirmed MI during the same period. Patients not on anticoagulation therapy at the time of presentation and those with incomplete clinical or radiological data were excluded from the study.

RESULTS

There were 16 patients in IMH group and 54 patients in MI group. Clinical features like overt rectal bleeding or melena, and prolonged prothrombin time-international normalized ratio (PT-INR) more than three, and CT features like proximal location in the bowel, increased bowel wall thickness, hyperdensity on plain scan (>40 Hounsfield units (HU)), and short segment bowel involvement were significantly associated with IMH. Visualization of embolus and absent mesenteric vasculature to a segment of intestine in CT was significantly associated with MI.

CONCLUSION

Attention to clinical features and early CT scan can aid in early differentiation of IMH from MI, facilitating appropriate intervention early in the course of disease.

Multidetector CT imaging of post-robot-assisted laparoscopic radical prostatectomy complications

Background

Robot-assisted laparoscopic radical prostatectomy (RALRP) is currently accepted as the preferred minimally invasive surgical treatment for localised prostate cancer, with optimal oncologic and functional results. Despite growing surgical experience, reduced postoperative morbidity and hospital stays, RALRP-related complications may occur, which are severe in 5–7 % of patients and sometimes require reoperation. Therefore, in hospitals with an active urologic surgery, urgent diagnostic imaging is increasingly requested to assess suspected early complications following RALRP surgery.

Methods

Based upon our experience, this pictorial review discusses basic principles of the surgical technique, the optimal multidetector CT (MDCT) techniques to be used in the postoperative urologic setting, the normal postoperative anatomy and imaging appearances.

Results

Afterwards, we review and illustrate the varied spectrum of RALRP-related complications including haemorrhage, urinary leaks, anorectal injuries, peritoneal changes, surgical site infections, abscess collections and lymphoceles, venous thrombosis and port site hernias.

Conclusion

Knowledge of surgical procedure details, appropriate MDCT acquisition techniques, and familiarity with normal postoperative imaging appearances and possible complications are needed to correctly perform and interpret early post-surgical imaging studies, particularly to identify those occurrences that require prolonged in-hospital treatment or surgical reintervention.

Teaching points

• Robot-assisted laparoscopic radical prostatectomy allows minimally invasive surgery of localised cancer

• Urologic surgeons may request urgent imaging to assess suspected postoperative complications

• Main complications include haemorrhage, urine leaks, anorectal injuries, infections and lymphoceles

• Correct multidetector CT techniques allow identifying haematomas, active bleeding and extravasated urine

• Imaging postoperative complications is crucial to assess the need for surgical reoperation

Abdominal vascular emergencies: US and CT assessment

Acute vascular emergencies can arise from direct traumatic injury to the vessel or be spontaneous (non-traumatic).The vascular injuries can also be divided into two categories: arteial injury and venous injury.Most of them are life-treatening emergencies, sice they may cause an important ipovolemic shock or severe ischemia in their end organ and require prompt diagnosis and treatment.In the different clinical scenarios, the correct diagnostic approach to vascular injuries isn't firmly established and advantages of one imaging technique over the other are not obvious.Ultrasound (US) is an easy accessible, safe and non-invasive diagnostic modality but Computed Tomography (CT) with multiphasic imaging study is an accurate modality to evaluate the abdominal vascular injuries therefore can be considered the primary imaging modality in vascular emergencies.The aim of this review article is to illustrate the different imaging options for the diagnosis of abdominal vascular emergencies, including traumatic and non traumatic vessel injuries, focusing of US and CT modalities.

Hemorrhagic complications of anticoagulant therapy: role of multidetector computed tomography and spectrum of imaging findings from head to toe

Highly effective in preventing and treating thromboembolic conditions in acute and chronic settings, anticoagulant therapy is associated with a non-negligible risk of hemorrhagic complications with a considerable clinical impact. Advanced age and comorbidities further increase the risk of bleeding during heparinization, treatment with low-molecular-weight heparins or long-term oral warfarin anticoagulation. Multidetector computed tomography represents the mainstay diagnostic technique to image-suspected hemorrhages in anticoagulated patients, as it can quickly assess presence, site, and extent of hemorrhage, identify active bleeding, and possible underlying diseases. Cross-sectional imaging appearances of the wide spectrum of anticoagulant therapy-related bleeding complications are hereby presented, including peripheral and thoracic-abdominal wall muscular hematomas, intrathoracic, abdominal, retroperitoneal genitourinary, gastrointestinal, and brain hemorrhages. Prompt recognition and comprehensive diagnostic assessment with multidetector computed tomography allow clinicians to correctly choose treatment modification or withdrawal, surgery, or interventional procedures as needed, with the aim to reduce the associated morbidity and mortality.

Small bowel obstruction: what to look for

Small bowel obstruction (SBO) is a common clinical syndrome for which effective treatment depends on a rapid and accurate diagnosis. Despite advances in imaging and a better understanding of small bowel pathophysiology, SBO is often diagnosed late or misdiagnosed, resulting in significant morbidity and mortality. A comprehensive approach that includes clinical findings, patient history, and triage examinations such as plain abdominal radiography will help the clinician develop an individualized treatment plan. When an SBO is accompanied by signs of strangulation, emergent surgical treatment is advised. If surgery cannot be performed immediately or if a partial obstruction is suspected, then a more detailed radiologic work-up is needed. The imaging techniques used subsequently vary according to the initial findings. If a low-grade partial obstruction is suspected, volume-challenge enteral examinations such as enteroclysis and computed tomographic (CT) enteroclysis are preferred. If a complete or high-grade obstruction is suspected, cross-sectional studies such as ultrasonography or multidetector CT are used to exclude strangulation. An algorithmic approach to imaging is proposed for the management of SBO to achieve accurate diagnosis of the obstruction; determine its severity, site, and cause; and assess the presence of strangulation. Radiologists have a pivotal role in clinical decision making in cases of SBO by providing answers to specific questions that significantly affect management.

CT Criteria for Differentiating Abdominal Hemorrhage: Anticoagulation or Aortic Aneurysm Rupture?

OBJECTIVE

The purpose of our study was to test the hypothesis that CT criteria would allow accurate diagnosis of the specific cause of abdominal hemorrhage in patients with coagulopathy or abdominal aortic aneurysm.

CONCLUSION

Attention to specific CT criteria allows accurate diagnosis of the specific cause of spontaneous abdominal hemorrhage even in patients who have both coagulopathy and an abdominal aortic aneurysm.

The CT findings of abdominal anticoagulant-related hematomas

Spontaneous bleeding is a serious complication of anticoagulation that should be promptly recognized and treated. The clinical manifestations vary and are related to the site of the hemorrhage. CT, a simple and safe imaging modality, plays an important role in the accurate determination of the presence or absence of an anticoagulant-related bleed, its extent, and its precise location. This pictorial article reviews and demonstrates the CT findings of a variety of anticoagulant-related hematomas at various anatomical locations in the abdomen.

Nontraumatic Emergent Abdominal Vascular Conditions: Advantages of Multi–Detector Row CT and Three-Dimensional Imaging

In the past decade, great strides have been made in the development of helical computed tomography (CT) that have led to shorter scanning time and higher spatial resolution. A wide range of traumatic and nontraumatic emergent conditions may be quickly and accurately diagnosed with multi-detector row CT. Multi-detector row CT angiography is the preferred method for imaging in emergent abdominal vascular conditions because it enables the acquisition of high-spatial-resolution volumetric image data during a single breath hold. Unlike catheter angiography, multi-detector row CT angiography not only depicts the vessels but also allows assessment of perfusion in adjacent organs. To make the most effective diagnostic use of multi-detector row CT angiography and three-dimensional image postprocessing, radiologists must be familiar with the optimal CT angiographic protocols and with the typical CT findings in various emergent vascular conditions. This article describes the protocols used in 11 patients with conditions including ruptured abdominal aortic aneurysm, secondary aortoduodenal fistula, splanchnic segmental arterial mediolysis, and Wegener-type vasculitis with visceral involvement. All of the diagnoses in these 11 cases were made in the emergency department, and the delay between imaging and diagnosis was decreased considerably by avoiding the transfer of patients for catheter angiography.

Spontaneous intraperitoneal hemorrhage: imaging features

Spontaneous intraperitoneal bleeding can result from a vast array of etiologies. Fortunately, most are uncommon and currently available imaging modalities can be used to differentiate them in almost all cases. Meticulous imaging technique and careful observation of key imaging features are important for accurate characterization of the organ of origin of the spontaneous bleeding. CT is the single most important imaging technique in the detection and characterization of spontaneous intraperitoneal bleeding. Further development in multidetector technology, such as the introduction of new machines with 8 or 16 detectors, should improve the effectiveness of CT further. Sonography and MR imaging are complimentary to CT, especially in patients with pelvic abnormalities or equivocal CT findings.

Role of thrombin in CNS damage associated with intracerebral haemorrhage: opportunity for pharmacological intervention?

Intracerebral haemorrhage (ICH) results in high mortality and morbidity. The most important causes of neurological deterioration after ICH are progression of oedema and injury to nerve cells and axons surrounding the haematoma, as well as haematoma enlargement. Recent studies have indicated that thrombin, formed upon clotting of the haematoma, plays an important role in these processes. As opposed to conventional therapeutic approaches, administration of a thrombin inhibitor could effectively limit oedema formation and neuronal damage, improving survival and functional outcome. A small, preliminary clinical trial has suggested that antithrombin therapy with intravenously administered argatroban may be useful in treatment of ICH. Randomised, controlled studies are needed to confirm these initial findings.

Spiral CT and three-dimensional CT of musculoskeletal pathology. Emergency room applications

Spiral CT is a fast and effective modality for evaluating a wide variety of musculoskeletal abnormalities in the emergency department setting. The role of spiral CT in evaluating musculoskeletal trauma and musculoskeletal inflammation and infections is discussed, as is the use of multiplanar and three-dimensional imaging.

Unenhanced CT of abdominal and pelvic hemorrhage

CT performed without oral or intravenous contrast is the initial imaging study of choice in many situations for the detection of hemorrhage anywhere in the abdomen and pelvis. The presence or absence of hemorrhage can be determined rapidly, and the amount and precise location of hemorrhage can also be evaluated. This article reviews the appearances and the common and unusual etiologies of abdominal and pelvic hemorrhage on unenhanced CT. The role of intravenous contrast-enhanced CT in patients with known or suspected abdominal and pelvic hemorrhage is also examined.

Role of blood clot formation on early edema development after experimental intracerebral hemorrhage

BACKGROUND AND PURPOSE

Blood "toxicity" is hypothesized to induce edema and brain tissue injury following intracerebral hemorrhage (ICH). Lobar ICH in pigs produces rapidly developing, marked perihematomal edema (>10% increase in water content) associated with clot-derived plasma protein accumulation. Coagulation cascade activation and, specifically, thrombin itself contribute to edema development during the first 24 hours after gray matter ICH in rats. In the present study, we sought to determine whether blood clot formation is necessary for edema development by comparing intracerebral infusions of heparinized and unheparinized blood in pig (white matter) and in rat (gray matter). We also examined heparin's effect on thrombin-induced gray matter edema.

METHODS

In pigs, we infused autologous blood (with or without heparin) into the cerebral white matter to produce lobar hematomas and froze the brains in situ at 1, 4, or 24 hours after ICH. We determined hematomal and perihematomal edema volumes on coronal sections by computer-assisted morphometry. In rats, we infused either blood or thrombin (with or without heparin) into the basal ganglia and measured water, sodium, and potassium contents at 24 hours after ICH.

RESULTS

In pigs, unheparinized blood induced rapid (at 1 hour) and prolonged (24 hours) perihematomal edema (average volume, 1.29+/-0. 20 mL; n=6). No perihematomal edema was present following heparinized blood infusions (n=6). In rats, unheparinized blood produced significantly greater edema than heparinized blood infusions. As with whole blood, thrombin-induced gray matter edema at 24 hours was significantly reduced by coinjection of heparin.

CONCLUSIONS

After ICH, blood clot formation is required for rapid and prolonged edema development in perihematomal white and gray matter. Thrombin also contributes to prolonged edema in gray matter.