From the Guidelines
When evaluating for abdominal hernia, a CT scan is the preferred imaging modality, particularly for diagnosing diaphragmatic hernias, due to its high sensitivity and specificity of 14–82% and 87%, respectively 1.
The choice between CT scan and ultrasound for evaluating abdominal hernia depends on the specific clinical context and the type of hernia suspected. For diaphragmatic hernias, CT scan is the gold standard, offering detailed images of the diaphragm and surrounding structures, which is crucial for identifying the presence, location, and size of the diaphragmatic defect 1.
Key advantages of CT scans in this context include:
- High accuracy in determining the presence and characteristics of diaphragmatic hernias
- Ability to evaluate intrathoracic complications of herniated abdominal organs
- Detailed radiological findings that can confirm the diagnosis, such as diaphragmatic discontinuity, segmental non-recognition of the diaphragm, and the "Dangling diaphragm" sign 1
While ultrasound is beneficial for its lack of radiation, lower cost, and real-time assessment, its utility is more limited in the diagnosis of diaphragmatic hernias compared to CT scans. Ultrasound may be preferred for initial assessments of uncomplicated hernias in other locations, like the groin or umbilical region, due to its advantages in these contexts. However, for diaphragmatic hernias or when complications are suspected, the detailed imaging provided by a CT scan is invaluable 1.
Therefore, the evaluation approach should prioritize a thorough physical examination, followed by a CT scan if a diaphragmatic hernia is suspected, given its superior diagnostic capabilities for this specific condition 1.
From the Research
Imaging Modalities for Abdominal Hernia Evaluation
When evaluating for abdominal hernia, the choice between a computed tomography (CT) scan and ultrasound depends on several factors.
- CT scans are considered the imaging modality of choice for assessing known adult abdominal hernias in both elective and acute circumstances due to their rapid acquisition, capability of multiplanar reconstruction, good spatial resolution, and excellent sensitivity for most complications 2.
- Ultrasound, on the other hand, is useful for adult groin assessment and is the imaging modality of choice for pediatric abdominal wall hernia assessment 2, 3, 4.
- Ultrasound is also helpful when a recurrent hernia, surgical complication after repair, or other cause of groin pain is suspected, and it can provide more efficient and economical treatment by expediting clinical management 5, 3, 4.
Specific Considerations
- For inguinal hernias, ultrasonography has high sensitivity and specificity, making it an accurate method for evaluation, particularly for ruling out an inguinal hernia when findings are negative 4.
- However, preoperative CT imaging in acutely symptomatic hernia cases can introduce surgical delay and is associated with an increased need for bowel resection 6.
- The choice of imaging modality should be based on the specific clinical scenario, taking into account the patient's symptoms, physical examination findings, and the potential need for urgent surgical intervention.
Key Points
- CT scans are preferred for assessing known adult abdominal hernias due to their high sensitivity and ability to detect complications.
- Ultrasound is suitable for adult groin assessment, pediatric abdominal wall hernias, and for evaluating suspected recurrent hernias or complications after repair.
- The choice of imaging modality should be guided by the clinical context and the need for timely surgical intervention.