Emergencies: abdominal and genitourinary

Computed tomography (CT) imaging - often preceded by conventional radiography - represents the major imaging modality for the diagnosis of acute aortic syndromes. This lecture will review the various underlying diseases of acute aortic syndrome, demonstrate typical imaging features enabling the diagnosis and discuss management options depending on the type, extent, and location of the disease. Clinical examples will be shown.

Abdominal traumas can be classified into two categories: penetrating and blunt traumas. Abdominal injuries are more often observed in the setting of polytrauma; in fact, they are present in about 10% of patients admitted to level 1 trauma . However, only 11% of patients with abdominal trauma require laparotomy when a correct imaging-guide approach is performed. In fact, because the management of trauma patients mainly depends on the mechanism and severity of the trauma, it is crucial to choose the correct imaging modality and/or technique when evaluating a trauma patient on the basis of these two parameters. For example, an ultrasound examination, possibly integrated by contrast-enhanced ultrasonography, may be adequate to image a minor blunt abdominal trauma. This modality, however, is not appropriate when evaluating a severe blunt or penetrating abdominal trauma or even a polytrauma patient with a minor mechanism of injury. Multidetector CT is actually the modality of choice for evaluating severe trauma patients, accompanied by an appropriate CT protocol to image these patients so as to avoid missed injuries and to correctly detect abdominal solid organ injuries, mesenteric and intestinal injuries and abdominal vascular traumatic lesions. Moreover, due to the fact that during the past decades there has been a major change from operative to increasingly conservative management of abdominal traumatic injuries, even in patients with higher grades of injuries or those with older age, imaging features together with hemodynamic considerations play an essential role in the treatment choice: surgery, conservative management, and endovascular treatment.

According to the American Association of Surgeons in Trauma (AAST), approximately, 10% of all trauma admissions have kidney injuries. Blunt traumas can be graded in a 5-point Renal Injury Scale. On the basis of the patient’s clinical findings an imaging algorithm is set. In general, patients that are normotensive with microscopic hematuria have less than 0.2% risk of serious kidney damage and imaging is unnecessary, whereas patients with either: (A) gross hematuria, (B) microscopic haematuria and blood pressure less than 90 mmHg or occasionally, (C) microscopic haematuria will require imaging. Contrast-enhanced CT is the way to go. Imaging should be in 3 phases (cortico-medullary, delayed 3-5 min and late phase (more than 10 min). Image reading should be by multiplane approach. Most of the findings do not require surgical intervention. But the rest do. On the basis of case presentations, findings will be analysed, discussed and correlated to the patient’s clinical status and treatment possibilities, including where and which signs to look for. Which modality could be used to solve the diagnostic problem when the clinical picture does not fit with the radiological picture. Relevant questions will be asked during this session for the participants to vote and the results will be discussed.

Urinary tract (UT) obstruction secondary to urolithiasis is the most common urologic emergency in patients presenting with abdominal pain. Serious complications of acute obstruction include ureteral rupture, pyelonephrosis or abscesses. Radiologists need to define the extent of obstruction, its likely duration and whether an intervention is required, aware that ultrasound (US) is usually normal in case of acute onset. In such cases computerised tomography (CT) is the gold standard diagnostic tool. UT infection (UTI) is another common emergency and it may vary in severity, from ureteral to focal renal infection, emphysematous pyelonephritis or pyonephrosis. UTI diagnosis is usually clinical, but in case of uncertainty CT provides early diagnosis, outlining the extent and severity of the disease. Magnetic resonance diffusion-weighted imaging (DWI) is of particular value when differentiating pyonephrosis from simple hydronephrosis. DWI of the kidneys is highly sensitive for the detection of focal or diffuse infections, reason why is gaining more and more popularity. T2-weighted (static fluid) urography is performed in pregnant women to outline the ureters in their entirety. A challenge of MR urography is the differentiation between physiologic hydronephrosis and pathologic obstruction. Vascular UT emergencies include renal infarcts (commonly of thromboembolic origin), renal vein thrombosis (typical of hypercoagulable states and neoplastic patients), and spontaneous hemorrhage (due to angiomyolipoma rupture). These are among the most common non-traumatic UT emergencies and it is fundamental for every radiologist to be fully confident in their diagnosis. The role of each imaging modality will be interactively discussed in the different clinical scenarios.

Acute abdominal vascular emergencies could be traumatic or non-traumatic according to their aetiology. Risks of rapid blood loss with development of hypovolemic shock and critical organ ischaemia dictate the need for rapid and accurate diagnostic assessment. These emergencies could be a result of arterial or venous pathology. Major types of vessel injuries are ruptures accompanied by active haemorrhage, lacerations or dissections, thrombotic or mechanical occlusions with following organ ischaemia, and the formation of pseudoaneurysms and fistulae. CT is a most used diagnostic technique in such cases. It has several advantages over abdominal US. CT is quick, covers large anatomical areas, is widely available, and its results are not dependent on patient's preparation. MRI or hybrid imaging is not routinely used in such cases. The preferable technique is biphasic CT. In cases of acute vascular emergencies, CT is comparable to catheter angiography. CT can show the direct signs of vessel injury, intraluminal thrombi or extravascular blood and clots, and ischaemia of critical organs (e.g. mesenteric ischaemia). Modern systems can be used to see so-called "blush" - a sign of acute extravasation of contrast material. It helps to locate the site of continuing acute bleeding. Potential pitfalls in CTA interpretation (missed acute bleeding or thrombosis) could be related to the low rate of bleeding, stopped bleeding, dilution of blood by fluid, and missed signs of organ ischaemia. The use of abdominal MDCT in cases of vascular emergencies helps to define and plan the best treatment strategy (endoscopic intervention, angiographic embolization, surgery, or active surveillance).

Vascular abdominal emergencies are not common but, when present, may be catastrophic, with significant morbidity and, frequently, mortality. The physical examination may not reveal clear abnormalities, making the diagnosis more difficult. Due to wide MDCT technology availability, the first-line assessment of vascular abdominal emergencies is CTA. The findings of various types of vessel injury include laceration, rupture with active haemorrhage, occlusion and, for arteries formation of aneurysm, pseudoaneurysm, dissection or fistula. Most of them are life-threatening emergencies, since they may cause a heavy hypovolemic shock and/or severe organ ischaemia and therefore prompt diagnosis and treatment are required. Due to the rapidly growing field of endovascular treatment, interventional radiology is increasingly used as a first-line treatment. This presentation focuses on differences in clinical and radiological presentations of vascular emergencies, usual and unusual emergencies, endovascular methods of treatment and what is most important in choosing appropriate treatment strategy: endovascular or open surgery.

Closed-loop small bowel obstruction (CL-SBO) is a form of mechanical intestinal obstruction in which a segment of bowel is occluded at two contiguous points. Adhesive bands and internal and external hernias are the main causes of CL-SBO. CL-SBO is the most common cause of strangulation with a rate of intestinal ischaemia ranging from 43 to 84 %. Computed tomography (CT) remains actually the best modality to detect ischaemia in small bowel obstructions (SBO) with reported sensitivities ranging from 73% to 100% and specificities from 61% to 100%. In patients with CL-SBO and absence of other CT signs of ischaemia, non-surgical management is successful in 25% of the cases. Increased unenhanced bowel wall attenuation is the only CT finding significantly associated with bowel necrosis in patients with adhesive bands or internal hernias CL-SBO. When present, this sign could help to differentiate reversible partial mural bowel ischaemia from irreversible transmural bowel infarction.

Evaluation of acute abdominal conditions is sometimes difficult. Various factors can obscure the underlying cause, delaying the correct diagnosis with subsequent adverse patient outcome. Imaging is one of the most important diagnostic tools in acute abdomen and many times radiological examinations are done prior to use of other diagnostic tools. This presentation will demonstrate the examples of usual and unusual entities of the upper abdominal organs that are seen as emergency conditions (imaging on demand, not planned) and require timely intervention to limit morbidity and mortality. Examples of life-threatening bleeding conditions of the liver and spleen, examples of immediate treatment requiring infectious diseases of the liver, cases of inflammatory processes of the pancreas and unexpected lesions of the adrenals will be shown. The relation of the organ pathology and the clinical presentation will be discussed, as a potential guide or even indication of danger, to proceed with the correct radiological diagnosis; expected vs surprising radiological findings (treat the patient, not the image). Appropriate imaging techniques will discussed, with specific emphasis on CT, as a most valued tool, demonstrating the advances of imaging in the evaluation of emergency pathologies. A short overview of interventional techniques will be discussed as well, as an alternative to surgical procedures to treat effectively patients with high morbidity, without open or laparoscopic surgery.

With a speedy workflow, as is very often necessary at the department of emergency radiology, or on the night shift, it might be quite easy to overlook some important pathologies. Acquiring some useful habits such as measuring densities or comparing and paying attention to 'hints' we see during radiological studies could guide us to serious conditions not noticed initially. Good clinical and laboratory information are often necessary to come to the right conclusion.