Case 332: Tyrosine Kinase Inhibitor-induced Intestinal Lymphangiectasia

History A 65-year-old male patient with a history of sarcomatoid renal cell carcinoma and prior right nephrectomy developed recurrent disease adjacent to the inferior vena cava. The patient underwent surveillance imaging 7 months after initiation of treatment with maximum-dose pazopanib and less than 1 month after completing a 2-month regimen of palliative stereotactic body radiation therapy to the right nephrectomy bed and site of recurrence. (Stereotactic body radiation therapy was initiated 5 months after pazopanib treatment was initiated.) One month after initiating treatment with pazopanib and 6 months before the surveillance imaging, the patient developed diarrhea and required ongoing treatment with loperamide to control symptoms. He denied any fatigue, mouth sores, or extremity pain, but described some abdominal pain and discomfort associated with the diarrhea. He was not experiencing any fevers, and vital signs were normal. White blood cell count was normal at 5100/μL (5.1 ×109/L) (reference range, 4200-10 200/μL [4.2-10.2 ×109/L]), with all components of the differential count also being normal. A normal serum albumin level of 3.9 g/dL (39 g/L) (reference range, 3.5-5.0 g/dL [35-50 g/L]) and low serum total protein level of 6.1 g/dL (61 g/L) (reference range, 6.3-7.9 g/dL [63-79 g/L]) were noted. A comprehensive metabolic panel was performed, indicating a serum chloride level of 98 mmol/L (reference range, 100-108 mmol/L) and an alkaline phosphatase level of 121 U/L (2.02 μkat/L) (reference range, 45-115 U/L [0.75-1.92 μkat/L]). The patient underwent surveillance imaging with contrast-enhanced CT of the abdomen and pelvis in the venous phase.

Intestinal graft-versus-host disease

Graft-versus-host disease (GVHD) is a significant complication of allogeneic hematopoietic cell transplantation, an immune response against the host's tissues, resulting in inflammation and intestinal damage. GVHD is one of the leading causes of morbidity and mortality in this group of people, with an incidence of approximately 29.9% to 36% in acute grade II-IV gastrointestinal cases. Thus, the following is a report of a GVHD case where radiological findings were essential for diagnosis and treatment.

Diffusely Infiltrative Small Bowel Disease

Multiple infiltrative disorders can affect the small bowel, often resulting in diffuse small bowel wall thickening. These infiltrative disorders can manifest owing to various factors such as an influx of immunologic or neoplastic cells or the accumulation of substances within one or more layers of the intestinal wall. Although there can be considerable overlap in the appearances of infiltrative diseases on cross-sectional images, a comprehensive understanding of more specific ancillary imaging features and clinicopathologic correlation can substantially narrow the differential diagnosis. The radiologist can be instrumental in synthesizing the clinical and imaging information and guiding subsequent workup. The authors present a comprehensive review of the infiltrative disorders that commonly involve the small bowel. These disorders are organized on the basis of their pathophysiologic features, with multiple illustrative case examples to enhance understanding of these entities. CT and MRI are currently the most commonly used imaging modalities for evaluating small bowel disorders, and this review is focused on these two modalities. Detailed information regarding the pathologic features, clinical presentation, and imaging findings of these infiltrative disorders is provided to aid radiologists in recognizing and differentiating these conditions. ©RSNA, 2024.

Evaluation of Multidetector Computed Tomography in the Diagnosis of Intestinal Obstruction

Background Acute intestinal obstruction is a commonly encountered surgical emergency that is prevalent worldwide and has substantial morbidity and fatality rates. Therefore, swift and precise diagnosis is essential. While mortality rates in urban areas have declined due to timely medical intervention following early detection, the situation contrasts starkly in rural areas. Delays in presentations often lead to complications because of hesitancy toward surgery, economic challenges, and limited access to healthcare information. Therefore, this study aimed to evaluate how well multidetector computed tomography (MDCT) can help determine the site, cause, and level of intestinal obstruction compared to what the surgeons confirmed intraoperatively. Methodology A prospective study involving 101 patients was conducted at a tertiary care center in western Maharashtra from July 2022 to July 2024. The emergency department referred patients with clinical symptoms such as nausea and vomiting, abdominal distension, abdominal pain, inability to pass flatus, constipation, or diarrhea, which are commonly seen with intestinal obstruction. The study involved all patients who underwent a contrast-enhanced MDCT scan using both intravenous and oral contrast agents. We selected patients from both genders, regardless of their age; however, considerations were taken to include characteristics convenient and relevant to the study. Patients with abnormal serum creatinine levels or allergies to contrast were excluded from the study. We conducted CT examinations, noting findings such as the transition point between the dilated and collapsed loops, mesenteric fat stranding, and intestinal dilatation. An experienced radiologist made the final report, and the operating surgeons' notes on laparoscopy or open surgery for the same patient were reviewed to understand the operative findings. Results MDCT scans had high diagnostic accuracy for small and large bowel obstruction. Of the 101 patients, the mean age was 43.7 years. There were 70 (69.30%) males and 31 (30.69%) females. Sensitivity was 100%, specificity was 98.1%, positive predictive value was 83.7%, and negative predictive value was 100%. Conclusions MDCT demonstrated high sensitivity and specificity for diagnosing and determining the underlying cause of intestinal obstruction. It identified the location of the obstruction and discerned whether it originated from intrinsic, extrinsic, or intraluminal factors.

Radiological findings in poisoning by synthetic cannabinoids adulterated with brodifacoum

OBJECTIVES

Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide hazard. Here, we review the spectrum of imaging findings in adulterated cannabinoid poisoning.

MATERIALS AND METHODS

In this retrospective study, we used the Israeli Poison Information Center database to identify patients with cannabinoid-associated coagulopathy who presented to the Rambam Health Care Campus, where most patients were treated during an outbreak in northern Israel between September 2021 and June 2022. All relevant imaging studies for these patients were reviewed. We estimated the sensitivity of findings for cannabinoid-associated coagulopathy. Associations between a continuous variable and a dichotomous outcome were assessed with the Mann-Whitney U test.

RESULTS

We identified 48 patients (mean age 40 years ± 9 [SD], 43 males) with 54 hospitalizations due to cannabinoid-associated coagulopathy. Symptomatic hemorrhage was documented in 50 (93%) cases at presentation, most of whom (78%) had hemorrhage from multiple systems. The most common bleeding site was the genitourinary collecting system, with a characteristic sign of suburothelial bleeding in 16/18 of performed abdominal CTs (sensitivity 89% [CI 65-99%] for cannabinoid-associated coagulopathy). Intramural bowel hematomas were noted in 70% (7/10) of CTs of patients with gastrointestinal bleeding. Incidental bleeding sites were identified on imaging in 24% of patients. An increased number of bleeding sites was associated with need for vasopressors (difference in bleeding sites 3.00 [95% CI 0.99-4.00], p = 0.026).

CONCLUSION

CT plays a key role in the diagnosis and work-up of adulterated cannabinoid-associated coagulopathy. Characteristic signs include suburothelial hemorrhage and intramural bowel hematomas.

CLINICAL RELEVANCE STATEMENT

Recognition of radiological signs of adulterated synthetic cannabinoid-associated coagulopathy is critical for optimizing outbreak control on the public health level and ensuring timely treatment on the individual patient level.

KEY POINTS

• Severe coagulopathy due to consumption of synthetic cannabinoids adulterated with brodifacoum, a long-acting anticoagulant, is an emerging worldwide threat. • Characteristic imaging signs include suburothelial bleeding, intramural bowel hematomas, and rare incidental bleeding sites. • Imaging has a pivotal role in optimizing outbreak control and ensuring timely and appropriate treatment.

Diagnostic Role of Multi-Detector Computed Tomography in Acute Mesenteric Ischemia

Mesenteric ischemia diagnosis is challenging, with an overall mortality of up to 50% of cases despite advances in treatment. The main problem that affects the outcome is delayed diagnosis because of non-specific clinical presentation. Multi-Detector CT Angiography (MDCTA) is the first-line investigation for the suspected diagnosis of vascular abdominal pathologies and the diagnostic test of choice in suspected mesenteric bowel ischemia. MDCTA can accurately detect the presence of arterial and venous thrombosis, determine the extent and the gastrointestinal tract involved, and provide detailed information determining the subtype and the stage progression of the diseases, helping clinicians and surgeons with appropriate management. CT (Computed Tomography) can differentiate forms that are still susceptible to pharmacological or interventional treatment (NOM = non-operative management) from advanced disease with transmural necrosis in which a surgical approach is required. Knowledge of CT imaging patterns and corresponding vascular pathways is mandatory in emergency settings to reach a prompt and accurate diagnosis. The aims of this paper are 1. to provide technical information about the optimal CTA (CT Angiography) protocol; 2. to explain the CTA arterial and venous supply to the gastrointestinal tract and the relevant ischemic pattern; and 3. to describe vascular, bowel, and extraintestinal CT findings for the diagnosis of acute mesenteric ischemia.

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.

High risk and low prevalence diseases: Mesenteric ischemia

INTRODUCTION

Mesenteric ischemia is a rare, frequently misdiagnosed, serious condition that carries with it a high rate of morbidity and mortality.

OBJECTIVE

This review highlights the pearls and pitfalls of mesenteric ischemia, including presentation, diagnosis, and management in the emergency department (ED) based on current evidence.

DISCUSSION

Mesenteric ischemia is an abdominal vascular emergency that includes superior mesenteric arterial embolism, arterial thrombosis, venous mesenteric ischemia, and non-occlusive mesenteric ischemia. It is associated with a variety of risk factors including older age, cardiovascular disease, hypercoagulable state, and end-stage renal disease. The presentation depends on the underlying pathophysiology. While arterial embolic disease may present with sudden, severe pain, the early stages of the disease and other forms can present with vague symptoms, including generalized abdominal pain, weight loss, vomiting, and diarrhea. Laboratory testing can suggest the disease with leukocytosis and elevated lactate, but normal values should not be used to exclude the diagnosis. The imaging modality of choice is triple phase computed tomography with non-contrast, arterial, and delayed phases. The initial ED management includes fluid resuscitation, symptomatic therapy, broad-spectrum antibiotics, and anticoagulation. Emergent consultation with a multidisciplinary team including diagnostic and interventional radiologists and cardiovascular and general surgeons is necessary for definitive treatment.

CONCLUSIONS

An understanding of mesenteric ischemia can assist emergency clinicians in diagnosing and managing this disease.

Imaging of intestinal vasculitis focusing on MR and CT enterography: a two-way street between radiologic findings and clinical data

Diagnosis of intestinal vasculitis is often challenging due to the non-specific clinical and imaging findings. Vasculitides with gastrointestinal (GI) manifestations are rare, but their diagnosis holds immense significance as late or missed recognition can result in high mortality rates. Given the resemblance of radiologic findings with some other entities, GI vasculitis is often overlooked on small bowel studies done using computed tomography/magnetic resonance enterography (CTE/MRE). Hereon, we reviewed radiologic findings of vasculitis with gastrointestinal involvement on CTE and MRE. The variety of findings on MRE/CTE depend upon the size of the involved vessels. Signs of intestinal ischemia, e.g., mural thickening, submucosal edema, mural hyperenhancement, and restricted diffusion on diffusion-weighted imaging, are common in intestinal vasculitis. Involvement of the abdominal aorta and the major visceral arteries is presented as concentric mural thickening, transmural calcification, luminal stenosis, occlusion, aneurysmal changes, and collateral vessels. Such findings can be observed particularly in large- and medium-vessel vasculitis. The presence of extra-intestinal findings, including within the liver, kidneys, or spleen in the form of focal areas of infarction or heterogeneous enhancement due to microvascular involvement, can be another radiologic clue in diagnosis of vasculitis. The link between the clinical/laboratory findings and MRE/CTE abnormalities needs to be corresponded when it comes to the diagnosis of intestinal vasculitis.

Selpercatinib Treatment of RET-Mutated Thyroid Cancers Is Associated With Gastrointestinal Adverse Effects

CONTEXT

Metastatic medullary thyroid carcinoma (MTC) and radioactive iodine-refractory differentiated thyroid carcinoma (RAI-R DTC) have poor prognosis and limited treatment options. Selpercatinib (LOXO-292), a selective kinase inhibitor targeting the RET gene, has shown a 69% to 79% objective response rate in this cohort with benefits in other tumors including lung cancer harboring the same oncogenic driver. Published reports describe only 17% of patients experiencing gastrointestinal (GI) adverse effects (AEs), which is in contrast to our local experience.

OBJECTIVE

Here we characterize the AEs and correlate them with radiological and histopathological findings.

METHODS

Sequential patients enrolled in LIBRETTO-001 at Royal North Shore Hospital, Sydney, Australia, with available imaging (n = 22) were recruited. Patients had regular visits with AEs documented and computed tomography (CT) scans every 3 months. CT at screening, at time of GI AE, and at most recent follow-up were reviewed and scored. Endoscopic examination was performed in 5 patients.

RESULTS

Of 22 patients in this cohort, the majority had somatic RET alterations (n = 18), most commonly p.Met918Thr (n = 14). Ten patients (50%) developed GI AEs. Dose reduction was required in 8 of the 10 patients, but none discontinued therapy. The majority had stable disease (n = 17). Gastric and small-bowel edema was evident in symptomatic patients after a median time of 67 weeks' treatment. Histological correlation in 5 patients revealed mucosal edema correlating with radiological evidence of congestion and edema.

CONCLUSION

GI AEs with selpercatinib may be more common than previously described. Most are self-limiting but often require dose adjustments. Histological evidence of mucosal edema observed in conjunction with the radiological findings of congestion and wall thickening suggest bowel-wall edema is a predominant mechanism of abdominal pain in these patients.

Small Bowel Volvulus Complicated by Bowel Infarction

Teaching Point: Torsion of a segment of the small bowel and its mesentery, together with closed loop obstruction and absent enhancement of paper-thin small bowel walls, is an alarm sign for small bowel volvulus complicated by acute bowel infarction.

Diagnosis of acute mesenteric ischemia assisted by dual-energy CT: a case report

In this case report, dual-energy CT was critical in the diagnosis of acute mesenteric ischemia by differentiating normal contrast-enhanced bowel and hemorrhagic necrosis. Iodine map showed a segment of small bowel with minimal contrast enhancement, and virtual non-contrast imaging revealed hyperattenuating bowel. This finding changed management for the patient and prevented complications from impending bowel perforation. Histopathological analysis confirmed hemorrhagic necrosis of the bowel segment. In cases of suspected bowel ischemia, dual-energy CT can distinguish bowel wall hemorrhage from contrast enhancement and allow for accurate diagnosis.

Multidetector computed tomography: a corner stone imaging modality in evaluation of acute small bowel diseases

Background

The diagnosis of acute small bowel diseases is one of the challenging issues that confronted by the radiologists so accurate diagnosis is essential to determine the appropriate way of management. CT has become the preferred imaging tool to evaluate acute small bowel diseases. Our study aimed to assess the role of MDCT in evaluation of acute abdomen secondary to small bowel origin by identification and differentiation between different acute small bowel pathologies.

Results

Thirty-eight patients presented with acute abdomen of small bowel origin from June 2019 to September 2019. The mean age of incidence was 48 ± 19 years ranged from 4 to 88 years. Males represented by 23 patients (60.5%). Acute exacerbation of inflammatory bowel diseases (Crohn’s disease) represented by (34.2%), small bowel obstruction (31.6%), ischemic bowel diseases (21.1%), small bowel perforation (10.5%) and infectious (TB enteritis) small bowel disease (2.6%). MDCT had an overall high sensitivity (97.3%) in assessment of acute small bowel diseases in correlation with post-operative data and follow-up response to management.

Conclusions

MDCT is a reliable diagnostic imaging tool for assessment of patients with acute abdomen secondary to small bowel origin with high-efficiency in differentiation between different pathological entities that causing acute abdomen.

Treatment response assessment following transarterial radioembolization for hepatocellular carcinoma

Transarterial radioembolization with yttrium-90 microspheres is an established therapy for hepatocellular carcinoma. Post-procedural imaging is important for the assessment of both treatment response and procedural complications. A variety of challenging treatment-specific imaging phenomena complicate imaging assessment, such as changes in tumoral size, tumoral and peritumoral enhancement, and extrahepatic complications. A review of the procedural steps, emerging variations, and timelines for post-treatment tumoral and extra-tumoral imaging changes are presented, which may aid the reporting radiologist in the interpretation of post-procedural imaging. Furthermore, a description of post-procedural complications and their significance is provided.

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.

Small bowel radiology

PURPOSE OF REVIEW

Recent advances in computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), and nuclear radiology have improved the diagnosis and characterization of small bowel pathology. Our purpose is to highlight the current status and recent advances in multimodality noninvasive imaging of the small bowel.

RECENT FINDINGS

CT and MR enterography are established techniques for small bowel evaluation. Dual-energy CT is a novel technique that has shown promise for the mesenteric ischemia and small bowel bleeding. Advanced US techniques and MRI sequences are being investigated to improve assessment of bowel inflammation, treatment response assessment, motility, and mural fibrosis. Novel radiotracers and scanner technologies have made molecular imaging the new reference standard for small bowel neuroendocrine tumors. Computational image analysis and artificial intelligence (AI) have the potential to augment physician expertise, reduce errors and variability in assessment of the small bowel on imaging.

SUMMARY

Advances in translational imaging research coupled with progress in imaging technology have led to a wider adoption of cross-sectional imaging for the evaluation and management of small bowel entities. Ongoing developments in image acquisition and postprocessing techniques, molecular imaging and AI have the strongest potential to transform the care and outcomes of patients with small bowel diseases.

CT appearance of gastrointestinal tract mucormycosis

Mucormycosis is a fungal infection caused by fungi of order mucorales. It is most commonly seen in patients with an impaired immune system due to any cause. Gastrointestinal mucormycosis is the least frequent type and may be a primary disease or a feature of generalized mucormycosis. Angioinvasion is the hallmark feature of mucormycosis, leading to bowel infarction which is the responsible for the most common clinical complaint of pain, and is also responsible for most of the imaging findings in this disease. The stomach is most commonly involved organ in the gastrointestinal tract and pneumatosis and lack of gastric wall enhancement are the most common imaging findings. Areas of bowel wall thickening and/ or lack of enhancement are seen in small bowel mucor and perforation can occur due to ischemia. Colonic mucor can present with mural thickening, or complete lack of definition or 'disappearance' of bowel wall with associated air containing collections. Mucormycosis affecting the bowel has a high mortality rate and early recognition and intervention may improve patient outcomes significantly. It should be suspected in immunosuppressed patients with imaging findings of unexplained bowel ischemia, infarction and/or pneumatosis without any obvious visible vascular thrombus.

Many faces of acute bowel ischemia: overview of radiologic staging

Acute bowel ischemia (ABI) can be life threatening with high mortality rate. In spite of the advances made in diagnosis and treatment of ABI, no significant change has occurred in the mortality over the past decade. ABI is potentially reversible with prompt diagnosis. The radiologist plays a central role in the initial diagnosis and preventing progression to irreversible intestinal ischemic injury or bowel necrosis. The most single imaging findings described in the literature are either non-specific or only present in the late stages of ABI, urging the use of a constellation of features to reach a more confident diagnosis. While ABI has been traditionally categorized based on the etiology with a wide spectrum of imaging findings overlapped with each other, the final decision for patient's management is usually made on the stage of the ABI with respect to the underlying pathophysiology. In this review, we first discuss the pathologic stages of ischemia and then summarize the various imaging signs and causes of ABI. We also emphasize on the correlation of imaging findings and pathological staging of the disease. Finally, a management approach is proposed using combined clinical and radiological findings to determine whether the patient may benefit from surgery or not.

Pearls, Pitfalls, and Conditions that Mimic Mesenteric Ischemia at CT

Acute mesenteric ischemia (AMI) is a life-threatening condition with a high mortality rate. The diagnosis of AMI is challenging because patient symptoms and laboratory test results are often nonspecific. A high degree of clinical and radiologic suspicion is required for accurate and timely diagnosis. CT angiography of the abdomen and pelvis is the first-line imaging test for suspected AMI and should be expedited. A systematic "inside-out" approach to interpreting CT angiographic images, beginning with the bowel lumen and proceeding outward to the bowel wall, mesentery, vasculature, and extraintestinal viscera, provides radiologists with a practical framework to improve detection and synthesis of imaging findings. The subtypes of AMI are arterial and venoocclusive disease, nonocclusive ischemia, and strangulating bowel obstruction; each may demonstrate specific imaging findings. Chronic mesenteric ischemia is more insidious at onset and almost always secondary to atherosclerosis. Potential pitfalls in the diagnosis of AMI include mistaking pneumatosis as a sign that is specific for AMI and not an imaging finding, misinterpretation of adynamic ileus as a benign finding, and pseudopneumatosis. Several enterocolitides can mimic AMI at CT angiography, such as inflammatory bowel disease, infections, angioedema, and radiation-induced enterocolitis. Awareness of pitfalls, conditions that mimic AMI, and potential distinguishing clinical and imaging features can assist radiologists in making an early and accurate diagnosis of AMI. ^©RSNA, 2020.

Imaging Spectrum of Infections in the Setting of Immunotherapy and Molecular Targeted Therapy

Advances in genomics and immunology are revolutionizing our understanding and treatment of cancer with improved treatment outcomes and patient quality of life. With the increasing use of immunotherapy and molecular targeted therapy, a variety of unusual and/or opportunistic infections are also observed. A variety of factors including use of immunosuppression for immune-mediated adverse effects play an important role for increasing the likelihood of these infections and form the basis of this case-based review. Imaging features of infections arising in patients undergoing immunotherapy regimens have not been previously highlighted. Prompt recognition of the spectrum of mycobacterial, bacterial, invasive fungal and viral pathogens can potentially lead to reduction in the high morbidity and mortality in this patient population.