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

From Head to Toe: Granulomatosis with Polyangiitis

Granulomatosis with polyangiitis (GPA) is an antineutrophil cytoplasmic antibody-associated vasculitis. It is an uncommon multisystem disease involving predominantly small vessels and is characterized by granulomatous inflammation, pauci-immune necrotizing glomerulonephritis, and vasculitis. GPA can involve virtually any organ. Clinical manifestations are heterogeneous and can be classified as granulomatous (eg, ear, nose, and throat disease; lung nodules or masses; retro-orbital tumors; pachymeningitis) or vasculitic (eg, glomerulonephritis, alveolar hemorrhage, mononeuritis multiplex, scleritis). The diagnosis of GPA relies on a combination of clinical findings, imaging study results, laboratory test results, serologic markers, and histopathologic results. Radiology has a crucial role in the diagnosis and follow-up of patients with GPA. CT and MRI are the primary imaging modalities used to evaluate GPA manifestations, allowing the differentiation of GPA from other diseases that could simulate GPA. The authors review the main clinical, histopathologic, and imaging features of GPA to address the differential diagnosis in the affected organs and provide a panoramic picture of the protean manifestations of this infrequent disease. The heterogeneous manifestations of GPA pose a significant challenge in the diagnosis of this rare condition. By recognizing the common and unusual imaging findings, radiologists play an important role in the diagnosis and follow-up of patients with GPA and aid clinicians in the differentiation of disease activity versus disease-induced damage, which ultimately affects therapeutic decisions. Online supplemental material is available for this article. ^©RSNA, 2021.

Lung involvement in ANCA-associated vasculitis

Lung involvement is one of the most common clinical features in ANCA-associated vasculitides (AAV), including granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA). In this review, we detail the five main presentations of pulmonary involvement in AAV: necrotizing granulomatous inflammation, tracheobronchial inflammation, pulmonary capillaritis, interstitial lung disease (ILD) and asthma with their clinical, radiological and therapeutic characteristics. The prevalence of these manifestations is variable according to the subtype of AAV, necrotizing granulomatous inflammation and tracheobronchial inflammation being defining features of GPA whereas ILD is primarily seen in patients with MPA, especially in association with ANCA directed against myeloperoxydase (MPO-ANCA), and asthma is characteristic of EGPA. Despite recent progresses in the diagnosis and management of these conditions, several questions remain and are discussed here, including local treatments for subglottic stenosis, the uncertain efficacy of plasma exchanges for alveolar hemorrhage, the potential role of antifibrotic agents in ILD associated with MPA, and the use of novel anti-IL-5 strategies in EGPA.

Discrepancies in interpretation of night-time emergency computed tomography scans by radiology residents

Background

In many emergency radiology units, most of the night-time work is performed by radiology residents. Residents’ preliminary reports are typically reviewed by an attending radiologist. Accordingly, it is known that discrepancies in these preliminary reports exist.

Purpose

To evaluate the quality of night-time computed tomography (CT) interpretations made by radiology residents in the emergency department.

Material and Methods

Retrospectively, 1463 initial night-time CT interpretations given by a radiology resident were compared to the subspecialist’s re-interpretation given the following weekday. All discrepancies were recorded and classified into different groups regarding their possible adverse effect for the emergency treatment. The rate of discrepancies was compared between more and less experienced residents and between different anatomical regions.

Results

The overall rate of misinterpretations was low. In 2.3% (33/1463) of all night-time CT interpretations, an important and clinically relevant diagnosis was missed. No fatalities occurred due to CT misinterpretations during the study. The total rate of discrepancies including clinically irrelevant findings such as anatomical variations was 12.2% (179/1463). Less experienced residents were more likely to miss the correct diagnosis than more experienced residents (18.3% vs. 10.9%, odds ratio [OR] = 1.82, P = 0.001). Discrepancies were more common in body CT interpretations than in neurological CTs (18.1% vs. 9.1%, OR = 2.30, P < 0.0001).

Conclusion

The rate of clinically important misinterpretations in CT examinations by radiology residents was found to be low. Experience helps in lowering the rate of misinterpretations.

Clues to vascular disorders at non-contrast CT of the chest, abdomen, and pelvis

Non-contrast chest CT scans are commonly performed while CT scans of the abdomen and pelvis are performed in a select subset of patients; those with limited renal function, an allergy to iodinated contrast, in the setting of suspected renal calculus, retroperitoneal hematoma, common duct calculus, abdominal aortic aneurysm with or without rupture, and in patients undergoing a PET-CT scan. In the absence of intravenous contrast, vascular structures may prove challenging to evaluate, yet their assessment is an important component of every non-contrast CT examination. We describe the key imaging features of both arterial and venous pathology, and review clues and common associated non-vascular findings, which can help the radiologist identify vascular disorders at non-contrast CT. Briefly, alternative imaging options are discussed.

Mobile Image Interpretation: Diagnostic Performance of CT Exams Displayed on a Tablet Computer in Detecting Abdominopelvic Hemorrhage

To investigate whether abdominopelvic hemorrhage shown on computed tomography (CT) images can be diagnosed with the same accuracy on a tablet computer as on a dedicated reading display. One hundred patients with a clinical suspicion of abdominopelvic hemorrhage that underwent biphasic CT imaging were retrospectively read by two readers on a dedicated reading display (reference standard) and on a tablet computer (iPad Air). Reading was performed in a dedicated reading room with ambient light conditions. Image evaluation included signs of an active hemorrhage (extravasation of contrast media) and different signs indicating a condition after abdominopelvic hemorrhage (hematoma, intestinal clots, vessel stump, free abdominopelvic fluid with a mean Hounsfield unit value >20, and asymmetric muscle volume indicating intramuscular hemorrhage). Sensitivity, specificity, and positive and negative predictive values (PPV/NPV) were calculated for the tablet-based reading. Active abdominopelvic hemorrhage (n = 72) was diagnosed with the tablet computer with a sensitivity of 0.96, a specificity of 0.93, a PPV of 0.97, and an NPV of 0.90. The results for the detection of the signs indicating a condition after abdominopelvic hemorrhage range from 0.83 to 1.00 in the case of sensitivity, from 0.95 to 1.00 in the case of specificity, from 0.94 to 1.00 in the case of the PPV, and from 0.96 to 1.00 in the case of the NPV. Abdominopelvic hemorrhage shown on CT images can be diagnosed on a tablet computer with a high diagnostic accuracy allowing mobile on-call diagnoses. This may be helpful because an early and reliable diagnosis at any time is crucial for an adequate treatment strategy.

Imaging and clinical findings in segmental arterial mediolysis (SAM)

Segmental arterial mediolysis (SAM) is an uncommon, non-atherosclerotic, non-inflammatory arteriopathy that tends to affect the medium-sized splanchnic branches of the aorta along with renal, carotid, cerebral, and coronary arteries. The clinical presentation ranges from asymptomatic to severe, life-threatening intra-abdominal hemorrhage and shock. SAM overlaps clinically and radiologically with other inflammatory vasculitides. This article describes the pathologic-radiologic correlation, imaging findings, and the management of the disease. Radiologists should be familiar with this disease entity as imaging plays a crucial role in the diagnosis.

Spectrum of Abdominal Aortic Disease in a Tertiary Health Care Setup: MDCT Based Observational Study

INTRODUCTION

Abdominal aortic disease is an important cause of clinical disability that requires early detection by imaging methods for prompt and effective management. Understanding regional disease pattern and prevalence has a bearing on healthcare management and resource planning. Non-invasive, conclusive imaging strategy plays an important role in the detection of disease. Multi-Detector Computed Tomography (MDCT) with its technological developments provides affordable, accurate and comprehensive imaging solution.

AIM

To evaluate regional demography of abdominal aortic disease spectrum detected using MDCT imaging data in a tertiary hospital.

MATERIALS AND METHODS

A descriptive study was conducted based on MDCT imaging data of patients who were investigated with clinical diagnosis of abdominal aortic disease, from March 2008-2010, over a period of 24 months. Patients were examined with the contrast-enhanced MDCT examination. Morphological diagnosis of the aortic disease was based on changes in relative aortic caliber, luminal irregularity, presence of wall calcification, dissection or thrombus and evidence of major branch occlusion. Patients were categorized into four groups based on imaging findings. MDCT information and associated clinical parameters were examined and correlated to management of patient. Descriptive statistical data, namely mean, standard deviation and frequency of disease were evaluated.

RESULTS

A total of 90 out of 210 patients (43%) were detected with the abdominal aortic abnormality defined by imaging criteria. Group I, comprising of patients with atherosclerosis -including those with complications, constituted 65.5% of the patients. Group II represented patients with aneurysms (45.5%). Group III, consisting of 32.2% of the patients, contained those with dissections. The rest of the patients, including patients with aorto-arteritis, were classified as group IV. Eight patients with aneurysm and one patient with aorto-arteritis were considered for surgical treatment. Ten patients with dissection underwent endovascular procedure. Rest of the patients was managed conservatively.

CONCLUSION

Aortic disease was observed in 43% of investigated patients. Atherosclerosis with and without aortic aneurysm constituted the largest group. MDCT provided comprehensive information about the lesion and associated complications. In view of the wider availability and desired imaging qualities, MDCT provided optimal information for diagnosis and management of aortic pathology. Majority of our patients (90%) were treated conservatively.

The Importance of Early Diagnosis and Treatment of Patients with Aortoenteric Fistulas Presenting with Herald Bleeds

BACKGROUND

Massive bleeding in patients with aortoenteric fistula (AEF) may be preceded by minor, intermittent gastrointestinal (GI) blood loss, termed the "herald bleed." The aims of this retrospective study were to: (i) analyze the interval between the herald bleed and onset of major GI hemorrhage and/or diagnosis of AEF and (ii) to evaluate the diagnostic roles of endoscopy and computed tomography imaging.

METHODS

Analysis of all patients diagnosed with AEF or iliac-enteric fistulas between 1994 and 2013 in a single institution.

RESULTS

In 31 of a total of 34 fistula cases, GI bleeding was the presenting symptom. Of these, 17 of 31 presented with herald bleed while 14 of 31 presented with massive GI bleeding. In patients with a herald bleed, median time from first bleeding to diagnosis was 14 (2-137) days. In 5/17 patients, herald bleeding preceded major hemorrhage with a median of 6 (4-92) days before a diagnosis of AEF was made or intervention could be initiated. CT angiography (CTA) showed abnormalities associated with a fistula in 27 (79%) cases, of which in 12 (35%) cases a fistula was actually identified. Esophagogastroduodenoscopy (EGD) demonstrated a fistula in 8 (25%) patients, while 50% of EGDs were completely normal.

CONCLUSIONS

Any patient with history of aortic surgery and GI bleeding should be considered to have an AEF until proven otherwise. The sensitivity of CTA for detecting AEF is substantially greater than that of EGD. The time interval between herald bleed and subsequent massive hemorrhage associated with AEF is unpredictable but may be as short as 4 days.

Computed Tomography in the Preoperative and Postoperative Evaluation of Kidney Transplant Patients

OBJECTIVES

Computed tomography is required for selection of living donors for kidney transplant. We assessed the diagnostic relevance and effectiveness of multiphase contrast-enhanced computed tomography angiography for evaluating patients before and after transplant.

MATERIALS AND METHODS

Thirty-two potentially living kidney donors (15 men and 17 women) underwent multiphase computed tomography angiography for evaluation before kidney transplant and 2 posttransplant recipients under went this test owing to abnormal vascularization. Computed tomography angio graphy was used to determine parenchymal blood-flow conditions and vascular architecture of the kidney grafts. All of the 34 patients underwent prestudy Doppler ultrasonography.

RESULTS

Additional renal arteries were found in 11 patients (32.3%). From them, a single additional renal artery, situated from the aorta to the lower segment of the kidney, was observed in 8 (72.7%) patients; dual additional renal arteries with equivalent caliber trunks were observed in 3 (27.3%) patients. An additional renal artery occurred more often in women in 6 (54.5%) donors. Concomitant renal pathology was detected in 3 (9.3%) of 32 donors: simple cysts in 2 donors and hydro nephrosis transformation in 1 donor. These 3 cases represented an accidental discovery and were therefore excluded from the list of donors. In addition, all donors underwent excretory-phase computed tomography, and their renal function and urinary collecting system results were evaluated. Two recipients with graft dysfunction presented with decreased venous return and delayed arterial filling of the renal arteries that manifested as delayed contrast in the kidney graft medulla. Renal parenchymal ischemic zones were consistent with microvasculature thrombosis, the most common cause of vascular complications in these recipients.

CONCLUSIONS

Multiphase computed tomography angiography is a necessary tool for assessing the structure and condition of vascular architecture in kidney donors and recipients. Individuals with ambiguous Doppler results, this test should be required; it is also warranted when renal graft vascular complications are suspected.

CT-angiography protocol with low dose radiation and low volume contrast medium for non-cardiac chest pain

AIM

To evaluate the diagnostic quality of a new multiple detector-row computed tomography angiography (MDCT-A) protocol using low dose radiation and low volume contrast medium techniques for evaluation of non-cardiac chest pain.

METHODS

Forty-five consecutive patients with clinically suspected noncardiac chest pain and requiring contrast-enhanced chest computed tomography (CT) were examined. The patients were assigned to the protocol, with 80 kilovolt (peak) (kV[p]) and 150 effective milliampere-second (eff mA-s). In our study group, 40 mL of low osmolar contrast material was administered at 3.0 mL/s.

RESULTS

In the study group, four patients with pulmonary embolism, four with pleural effusion, two with ascending aortic aneurysm and eight patients with pneumonic consolidation were detected. The mean attenuation of the pulmonary truncus and ascendant aortic locations was considered 264±44 and 249±51 HU, respectively. The mean effective radiation dose was 0.83 mSv for MDCT-A.

CONCLUSIONS

Pulmonary artery and the aorta scanning simultaneously was significantly reduced radiation exposure with the mentioned dose saving technique. Additionally, injection of low volume (40 cc) contrast material may reduce the risk of contrast induced nephropathy, therefore, facilitate the diagnostic approach. This technique can be applied to all cases and particularly patients at high risk of contrast induced nephropathy due to its similar diagnostic quality with a low dose and high levels of arteriovenous enhancement simultaneously.

Gastroduodenal artery aneurysm, diagnosis, clinical presentation and management: a concise review

Gastroduodenal artery (GDA) aneurysms are rare but a potentially fatal condition if rupture occurs. They represent about 1.5% of all visceral artery (VAA) aneurysms and are divided into true and pseudoaneurysms depending on the etiologic factors underlying their development. Atherosclerosis and pancreatitis are the two most common risk factors. Making the diagnosis can be complex and often requires the use of Computed Tomography and angiography. The later adds the advantage of being a therapeutic option to prevent or stop bleeding. If this fails, surgery is still regarded as the standard for accomplishing a definite treatment.

Gastroduodenal artery aneurysm, diagnosis, clinical presentation and management: a concise review

Gastroduodenal artery (GDA) aneurysms are rare but a potentially fatal condition if rupture occurs. They represent about 1.5% of all visceral artery (VAA) aneurysms and are divided into true and pseudoaneurysms depending on the etiologic factors underlying their development. Atherosclerosis and pancreatitis are the two most common risk factors. Making the diagnosis can be complex and often requires the use of Computed Tomography and angiography. The later adds the advantage of being a therapeutic option to prevent or stop bleeding. If this fails, surgery is still regarded as the standard for accomplishing a definite treatment.

[Review of pre- and post-treatment multidetector computed tomography findings in abdominal aortic aneurysms]

The increase in the frequency of abdominal aortic aneurysms (AAA) and the widely accepted use of endovascular aneurysm repair (EVAR) as a first-line treatment or as an alternative to conventional surgery make it necessary for radiologists to have thorough knowledge of the pre- and post-treatment findings. The high image quality provided by multidetector computed tomography (MDCT) enables CT angiography to play a fundamental role in the study of AAA and in planning treatment. The objective of this article is to review the cases of AAA in which CT angiography was the main imaging technique, so that radiologists will be able to detect the signs related to this disease, to diagnose it, to plan treatment, and to detect complications in the postoperative period.

Ectopic blood supply of hepatocellular carcinoma as depicted by angiography with computed tomography: associations with morphological features and therapeutic history

OBJECTIVE

To investigate the associations of ectopic blood supply of hepatocellular carcinoma (HCC) with its morphological features and therapeutic history.

METHODS

Three hundred and six patients with 373 HCC lesions were enrolled in this study, and underwent biphasic contrast-enhanced scans on a 64-section MDCT. The anatomy of ectopic blood supply, morphological characteristics of HCC including the size, location and pseudocapsule, and history of transcatheter arterial chemoembolization (TACE) therapy were quantitively assessed and statistically analyzed.

RESULTS

Ectopic blood supply was found in 30.8% (115/373) lesions. The ectopic arteries were predominantly composed of inferior phrenic artery (86/115) followed by left and right gastric artery (25/115). Tumor size, location, status of pseudocapsule, and history of TACE therapy could impact the origination of ectopic arteries (all p<0.05).

CONCLUSION

The ectopic feeding arteries of HCC predominantly composed of the perihepatic arteries are associated with the morphological features of the tumor and therapeutic history.

Current modalities in the diagnosis of pulmonary vasculitis

INTRODUCTION

This review addresses the pulmonary manifestations of the vasculitides, with a focus on diagnostic modalities. Haemorrhagic presentations (usually associated with nephritis: the pulmonary-renal syndrome) are the most common vasculitic cause of early death.

AREAS COVERED

The diagnostic modalities in the pulmonary vasculitides are reviewed, with a focus on primary systemic vasculitis. A literature search of original research and review articles on pulmonary vasculitides was undertaken using the PubMed database.

EXPERT OPINION

Small-vessel anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis, especially granulomatosis with polyangiitis (Wegener's granulomatosis) are the most frequent causes of pulmonary vasculitis and typically present as nodules, alveolar infiltrates (haemorrhagic or not), cavities or tracheobronchial stenosis. Lung involvement is less common in large-vessel vasculitis when pulmonary vascular abnormalities can be seen. No single test is pathogonomonic and diagnosis requires integration of clinical, laboratory, imaging and histological findings. Treatment follows similar regimens to other vasculitic presentations, with glucocorticoids in conjunction with immunosuppressive agents, and management of intercurrent sepsis and the increased risk of cardiovascular and thromboembolic events. Prompt diagnosis and intensive treatment of pulmonary vasculitis is essential to improve early mortality and long-term outcomes.

Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy, which is characterized by dissecting aneurysms resulting from lysis of the outer media of the arterial wall. The most common presentation is abdominal pain and hemorrhage in the elderly. Computed tomography (CT) and angiography imaging findings overlap with various vasculitides and include segmental changes of aneurysm and stenosis. A key distinguishing feature is the presence of dissections, the principle morphologic expression of SAM. Differentiation and exclusion of an inflammatory arteritis is crucial in appropriate management, as immunosuppressants generally used for treatment of vasculitis may be ineffective or even worsen the vasculopathy. Although the disease can be self-limiting without treatment or with conservative medical therapy, the acute process carries a 50% mortality rate and may necessitate urgent surgical and/or endovascular therapy. Prompt recognition and diagnosis are therefore of utmost importance in appropriate management of this rare entity.

Portal vein pseudoaneurysm with portoenteric fistula: an unusual cause for massive gastrointestinal hemorrhage

Pancreaticoduodenectomy (Whipple's procedure) is a commonly performed procedure for the treatment of pancreatic malignancies. Postoperative bleeding from adjacent arteries is a well-established complication of this procedure. This article describes an unusual case of massive gastrointestinal bleeding following pancreaticoduodenectomy due to the development of a portal vein pseudoaneurysm with a portoenteric fistula. The diagnosis was confirmed with multidetector computed tomography angiography; the different endovascular treatment options are discussed.

Myocardial ischemia in Wegener's granulomatosis: coronary atherosclerosis versus vasculitis

Wegener's granulomatosis (WG) is one of the most common small- and medium-sized necrotizing vasculitides that mainly affects the upper and lower respiratory tract and the kidneys. Cardiac manifestations in WG are relatively rare, and their role and place among different causes of mortality remain largely unknown. Substantially increased number of reports describing involvement of all structures of the heart, which underlie conduction disturbances, valvular disease, ischemic heart disease and other potentially serious conditions, underscores importance of comprehensive cardiovascular investigations and monitoring of patients with WG. The majority of previous reports and our current observation distinguish coronary vasculitis and thrombosis as a cause of myocardial ischemia and cardiovascular co-morbidities in WG. It seems plausible that inflammatory processes in this disease, like in some other systemic vasculitidies, do not predispose to accelerated atherogenesis. However, characteristic small- and medium-sized vasculitis still can manifest as myocardial ischemia and infarction. We overview diverse cardiac manifestations and present our own rare case of angina in the oligosymptomatic debut of WG. Importantly, in this case, coronarography failed to reveal atherosclerotic disease or thrombotic occlusion. However, magnetic resonance imaging (MRI) with adenosine test revealed subendocardial ischemia. As a result of immunosuppressive therapy with a steroid and cyclophosphamide, myocardial ischemia disappeared.

Myocardial Ischemia in Wegener’s Granulomatosis: Coronary Atherosclerosis Versus Vasculitis

Wegener’s granulomatosis (WG) is one of the most common small- and medium-sized necrotizing vasculitides that mainly affects the upper and lower respiratory tract and the kidneys. Cardiac manifestations in WG are relatively rare, and their role and place among different causes of mortality remain largely unknown. Substantially increased number of reports describing involvement of all structures of the heart, which underlie conduction disturbances, valvular disease, ischemic heart disease and other potentially serious conditions, underscores importance of comprehensive cardiovascular investigations and monitoring of patients with WG. The majority of previous reports and our current observation distinguish coronary vasculitis and thrombosis as a cause of myocardial ischemia and cardiovascular co-morbidities in WG. It seems plausible that inflammatory processes in this disease, like in some other systemic vasculitidies, do not predispose to accelerated atherogenesis. However, characteristic small- and medium-sized vasculitis still can manifest as myocardial ischemia and infarction. We overview diverse cardiac manifestations and present our own rare case of angina in the oligosymptomatic debut of WG. Importantly, in this case, coronarography failed to reveal atherosclerotic disease or thrombotic occlusion. However, magnetic resonance imaging (MRI) with adenosine test revealed subendocardial ischemia. As a result of immunosuppressive therapy with a steroid and cyclophosphamide, myocardial ischemia disappeared.

The radiological diagnosis and treatment of renal angiomyolipoma-current status

Angiomyolipomas (AMLs) are the most common benign renal neoplasm and are often discovered incidentally. Due to both an increase in the use of imaging, as well as advances in imaging technology, they are being increasing identified in the general population. As these lesions are benign, there is good evidence that the majority of them can be safely followed up without treatment. However, there is an increasing wealth of information available suggesting there are individuals with AMLs where prophylactic treatment is indicated to prevent complications such as haemorrhage. In such cases, treatment with radiological interventional techniques with subselective particle embolization has superseded surgical techniques in most cases. Even in emergency cases with catastrophic rupture, prompt embolization may save the patient with the additional benefit of renal salvage. Confident identification of a lesion as an AML is important as its benign nature obviates the need for surgery in most cases. The presence of fat is paramount in the confirmatory identification and characterization of these lesions. Although fat-rich AMLs are easy to diagnose, some lesions are fat poor and it is these cases where newer imaging techniques, such as in-phase and out-of-phase magnetic resonance imaging (MRI) may aid in making a confident diagnosis of AML. In this paper, we comprehensively review the imaging techniques in making a diagnosis of AML, including features of both characteristic lesions as well as atypical lesions. In addition, we discuss current guidelines for follow-up and prophylactic treatment of these lesions, as well as the increasing role that the interventional radiologist has to play in these cases.

CT and MRI in diseases of the aorta

OBJECTIVE

This review focuses on the role of CT and MRI in the diagnosis, follow-up, and surgical planning of aortic aneurysms and acute aortic syndromes, including aortic dissection, intramural hematoma, and penetrating aortic ulcer. It also provides a systematic approach to the definition, causes, natural history, and imaging principles of these diseases.

CONCLUSION

An understanding of the pathophysiology, natural history, and imaging features is the key to successful diagnosis and appropriate management of patients with these aortic diseases.

Successful treatment tailored to each splanchnic arterial lesion due to segmental arterial mediolysis (SAM): report of a case

Segmental arterial mediolysis (SAM) is a rare condition characterized by splanchnic arterial catastrophe caused by mediolysis. We report a 59-year-old man with a ruptured splenic arterial aneurysm who was successfully treated by coil embolization. He underwent additional resection of large gastroepiploic and residual splenic aneurysms. Pathological examination showed mediolysis and tearing, compatible with SAM. Furthermore, he developed acute dissection of the superior mesenteric artery (SMA) one and a half years later, demonstrated by computed tomography. This report demonstrates that SAM is characterized by multiple lesions of the splanchnic arteries at different times, and requires treatment suited to the lesions, including careful long-term observation.

Unsuspected mesenteric arterial abnormality: comparison of MDCT axial sections to interactive 3D rendering

OBJECTIVE

The purpose of our study was to determine how frequently significant mesenteric arterial abnormalities that were identified by interactive 3D CT with volume rendering and maximum intensity projection were detected by axial images alone in a series of patients for whom there was no clinical suspicion of mesenteric vascular disease. Axial CT and 3D interpretations were compared for lesions involving the celiac and superior mesenteric arteries or their branches. On a per-patient basis, the axial and 3D interpretations were equivalent in 24% (10/41) of the cases. Axial CT partially agreed with 3D CT in 10% (4/41), and no mesenteric arterial lesion was reported on axial CT in 66% (27/41). The 3D CT findings were supported by other imaging, surgery, clinical findings, or management in 49% (20/41) of the cases. The mesenteric lesions identified resulted in a change in patient management in 15% (6/41) of the subjects.

CONCLUSION

Unsuspected mesenteric arterial abnormality may elude diagnosis when axial MDCT sections are interpreted without 3D renderings.

Comparison of 2 different protocols for ingestion of low-attenuating oral contrast agent for multidetector computed tomography of the abdomen

OBJECTIVE

To evaluate 2 different oral contrast application protocols concerning degree of intestinal contrast filling and distension in multidetector computed tomography.

METHODS

Examinations of 260 patients were retrospectively analyzed. Group 1 (n = 205) was prepared with 1000 mL of water with 28 g of dissolved mannitol which was ingested for 1 hour; group 2 (n = 55) was prepared with 2000 mL of water containing 56 g of mannitol which was ingested for 2 hours. Small intestine was divided into 4 quadrants; colon was divided into 4 segments. Contrast filling and distension of bowel loops were graded with a 3-point scale and compared using chi2 testing.

RESULTS

Besides the right upper quadrant, no significant differences in contrast filling and distention were found for small bowel segments. Colonic segments were significantly better contrast filled and distended in group 2 (0.001 < P < 0.025).

CONCLUSIONS

A higher amount of water with 28 g/L of mannitol and a prolonged ingestion of oral contrast media result in significantly better contrast filling and bowel distension in the ileocecal region, the colon, and the rectum.

Negative Endoskopie sowie Mehrzeilendetektor-CT bei Patienten mit akuter unterer Gastrointestinalblutung

PURPOSE

To evaluate the clinical use of (99m)Tc red blood cell imaging (RBC imaging) in patients presenting with acute lower gastrointestinal (GI) bleeding and negative endoscopy and multislice computed tomography (MSCT) findings.

PATIENTS AND METHODS

In 31 consecutive patients with acute lower GI bleeding in whom the endoscopy findings were negative or the procedure was not feasible, dual-phase MSCT of the abdomen was performed [collimation 4x1 mm (arterial phase), 4x2.5 mm (venous phase)]. MSCT was followed by a (99m)Tc red blood cell scan in patients in whom no active bleeding was visible by CT. Images were created within 24 h after administration of the tracer, depending on the clinical symptoms. The results of the imaging modalities were correlated with clinical course and surgical treatment.

RESULTS

In 20 of 31 patients MSCT showed no active bleeding and a (99m)Tc red blood cell scan was performed. In 8 of 20 patients RBC imaging was also negative. Of these eight patients five were stable and did not require further diagnostic work-up; in the other three bleeding persisted and these patients required surgical treatment. In 12 of 20 patients active bleeding was demonstrated using a (99m)Tc red blood cell scan. Of 12 patients with positive RBC scintigraphy findings, 8 underwent surgery, where the site of bleeding was confirmed.

CONCLUSION

In patients with acute lower GI bleeding with negative or nondiagnostic endoscopy or MSCT findings, (99m)Tc red blood cell imaging is a useful tool in an emergency algorithm, improving the overall bleeding detection rate.

Acute abdomen: Added diagnostic value of coronal reformations with 64-slice multidetector row computed tomography

RATIONALE AND OBJECTIVES

We sought to assess retrospectively the added value of coronal reformations from isotropic voxels obtained with 64-slice multidetector row computed tomography (CT) of the acute abdomen.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and informed consent was waived. Multidetector helical 64-section CT (section thickness, 0.6 mm; pitch 1.75; table speed 35 mm/sec) was performed in 100 patients (60 women and 40 men; age range, 9-/+85 years; mean age, 45.2 years) with acute nontraumatic abdominal pain who had been referred from the emergency department. Axial images were reconstructed with 5-mm-thick sections at 5-mm intervals. The second data set was reformatted coronally, with 3-mm-thick sections at 3-mm intervals. Four independent, blinded readers with various level of training interpreted first the axial scans alone and then followed immediately by the coronal scans. Confidence in the visualization of anatomy and pathology was scored on a 5-point scale. The final diagnosis was determined by surgical and pathologic reports and by clinical follow-up in those who did not undergo surgery.

RESULTS

Based upon the individual patient's clinical history and other comorbid factors, 92 patients received intravenous contrast and 90 patients received oral contrast. In 45 patients, no CT abnormalities were detected for an explanation of the abdominal pain. Mean sensitivity and specificity of axial CT alone were 92.5% and 91%, respectively. No significant differences in sensitivity and specificity were observed for the use of combined axial and coronal images. For the most inexperienced reader, the coronal reformations were helpful in 95% of cases, while for the most experienced reader, the coronal reformations were helpful in 35% of the cases. The coronal images were deemed helpful in an average of 62.3% of the cases for the four readers. However, diagnosing subtle pathology in the abdominal wall was difficult on coronal reformations alone. Overall, coronal reformations improved diagnostic confidence and interobserver agreement over axial images alone for visualization of normal abdominal structures and in the diagnosis of abdominal pathology.

CONCLUSION

Axial and coronal reformations of 64-section multidetector row CT have equal sensitivity and specificity for the diagnosis of acute abdominal pathology. However, coronal reformations improved the diagnostic confidence for all readers but most significantly for the least experienced. Therefore, radiology departments with residents should consider routinely generating coronal images in patients with acute abdominal pain.

Acute gastrointestinal bleeding: detection of source and etiology with multi-detector-row CT

This study was conducted to determine the ability of multi-detector-row computed tomography (CT) to identify the source and etiology of acute gastrointestinal bleeding. Eighteen patients with acute upper (n = 10) and lower (n = 8) gastrointestinal bleeding underwent 4-detector-row CT (n = 6), 16-detector-row CT (n = 11), and 64-slice CT (n = 1) with an arterial and portal venous phase of contrast enhancement. Unenhanced scans were performed in nine patients. CT scans were reviewed to determine conspicuity of bleeding source, underlying etiology, and for potential causes of false-negative prospective interpretations. Bleeding sources were prospectively identified with CT in 15 (83%) patients, and three (17%) bleeding sources were visualized in retrospect, allowing the characterization of all sources of bleeding with CT. Contrast extravasation was demonstrated with CT in all 11 patients with severe bleeding, but only in 1 of 7 patients with mild bleeding. The etiology could not be identified on unenhanced CT scans in any patient, whereas arterial-phase and portal venous-phase CT depicted etiology in 15 (83%) patients. Underlying etiology was correctly identified in all eight patients with mild GI bleeding. Multi-detector-row CT enables the identification of bleeding source and precise etiology in patients with acute gastrointestinal bleeding.

Postpartum Hemoperitoneum Due to Avulsion of Pelvic Uterine Adhesion Band

A 31-year-old nulliparous woman presented in labor with preterm rupture of membranes at 35 weeks of gestation. The ensuing intrapartum course was uneventful, and she delivered a healthy infant (birth weight, 2,850 g) vaginally. Four hours after delivery, the patient had a syncopal episode due to hypovolemic shock. At laparotomy, a fibrous band between the right fallopian tube and uterus was found to be avulsed and actively bleeding, confirming preoperative findings obtained with multidetector row computed tomographic angiography.

Aorto-enteric fistula: CT findings

The objective of this pictorial essay is to present the different CT findings encountered in patients with aorto-enteric fistulas (AEFs). An AEF is a rare and sometimes disastrous occurrence, responsible for intermittent or massive gastrointestinal hemorrhage and hematemesis. CT provides fast and effective evaluation in hemodynamically stable patients suspected of having an AEF.

Value of dual-phase multislice CT prior to minimally invasive therapy of iatrogenic renal injuries

PURPOSE

To evaluate the diagnostic impact of multislice computed tomography (MSCT) in treatment planning prior to transarterial coil embolization of iatrogenic renal injuries.

METHODS

Nine patients (median age 54 years, range 36-66) with iatrogenic renal vascular injury were treated with superselective coil embolization. Prior to therapy, a dual-phase (40 and 120 seconds) contrast-enhanced MSCT was applied in 6 patients. Seven patients underwent renal ultrasonography. Multiplanar reconstructions of the MSCT scans were used to affirm ongoing bleeding and to localize the bleeding site at the level of the segmental or interlobar artery. MSCT and angiographic findings were compared to evaluate the accuracy of MSCT in the detection of the bleeding source prior to therapy.

RESULTS

Multiplanar reconstructions of early-phase MSCT scans allowed precise identification of the bleeding interlobar or segmental artery in all 6 cases prior to angiography. In one case, MSCT was even able to detect a source of bleeding that was not revealed by selective renal angiography.

CONCLUSIONS

Multiplanar reconstructions of MSCT data demonstrate not only the presence of hematoma but also confirm ongoing bleeding and the location of the feeder artery prior to minimally invasive therapy.

Multidetector CT Angiography of the Abdomen

Multidetector CT angiography (MDCTA) is redefining traditional imaging strategies of the vascular structures of the abdomen. Angiographic depiction of normal and variant anatomy is becoming the standard for evaluation and has a significant impact in transplant and oncologic surgery. MDCTA is increasingly being used for assessing diseases affecting the vasculature of the abdominal organs, including the abdominal aorta for treatment planning and post therapy follow-up.

[Acute abdomen]

Acute abdomen is not a disease entity on its own but describes a critical state of the patient which can be caused by numerous diseases. The surgeon and internist have to apply an interdisciplinary approach to enable a rapid decision on whether immediate laparotomy is mandatory. Few appropriate diagnostic procedures support decision making. In many cases there is an indication for immediate surgery, such as perforated gastric or duodenal ulcer, acute appendicitis, diverticulitis, ruptured aortic aneurysm, mechanic ileus, infarction of the mesenteric artery. This review is mainly focused on diseases which may present as acute abdomen but for which surgery is usually not indicated, such as acute pancreatitis. Furthermore, one also has to consider rare diseases in which laparotomy would clearly be a mistake, such as acute intermittent porphyria or intestinal pseudo-obstruction.

Multidetector row CT diagnosis of aortocaval fistula complicating aortic aneurysm: a case report

Aortocaval fistula is a rare complication of abdominal aortic aneurysm involving less than 1% of all abdominal aortic aneurysms and causing severe hemodynamic derangements from a large left-to-right shunt; early diagnosis and repair results in improved morbidity and lower mortality but the diagnosis is difficult. We report a case of prompt diagnosis obtained with thoracoabdominal aortic multidetector row angio-CT as the first imaging procedure and allowing immediate surgical repair. Our report emphasizes the crucial role played by multidetector row CT as the first procedure in thoracoabdominal vascular emergencies.

Multislice CT in the pre- and postinterventional evaluation of mesenteric perfusion

Multislice computed tomography angiography (CTA) has been found feasible for the evaluation of visceral vasculature. The development of multislice technology has overcome past limitations. First, the faster scanning speed increases volume coverage during a single breath-hold and improves the exploitation of contrast medium. Second, the better spatial resolution results in nearly isotropic voxels allowing reconstruction of high-resolution three-dimensional images with different algorithms. Volume rendering is capable of displaying the visceral vasculature from any external vantage point. Compared to conventional angiography, CTA not only delineates vessels but also depicts the anatomical relationship to adjacent structures and allows the evaluation of perfused organs. CTA also has become an emerging tool for the pre- and postinterventional assessment of vascular anatomy. The purpose of this pictorial essay is to present a spectrum of visceral vascular diseases and interventional and surgical therapies, and to highlight the role of postprocessing for their evaluation.