Clinical implications of perivascular fat stranding surrounding spontaneous isolated superior mesenteric artery dissection on computed tomography

Value of CT angiography in diagnosis and classification of spontaneous isolated superior mesenteric artery dissection and evaluation of its clinical symptoms

BACKGROUND

CT angiography (CTA) is a non-invasive, rapid imaging technology and can accurately examine and evaluate the degree and range of stenosis of diseased vessels and lumens. CTA has been routinely used for early screening of spontaneous isolated superior mesenteric artery dissection (SISMAD). This study further explored the diagnostic value of CTA in the classification of SISMAD and the evaluation of clinical symptoms.

AIM

To assess the value of CTA in the diagnosis of SISMAD and the evaluation of its clinical symptoms.

METHODS

Ninety-five suspected SISMAD patients in our hospital from October 2019 to January 2022 were selected for CTA examination. Clinical results (digital subtraction angiography or surgical results) were used as the "gold standard" to analyze the value of CTA in diagnosing SISMAD, and to compare the measurement parameters of CTA in SISMAD patients with and without clinical symptoms. The correlation between the measurement parameters of CTA and the clinical symptoms of SISMAD patients was analyzed, and the consistency between the classification of SISMAD by CTA and the clinical results was assessed by kappa test.

RESULTS

The area under the curve (AUC) of CTA for the diagnosis of SISMAD was 0.953 (95% confidence interval [CI]: 0.889-0.986), the diagnostic sensitivity and specificity were 90.63% and 100.00%, respectively, and the Yoden index was 0.906. The interlayer length and the degree of true cavity stenosis were greater and the diameter of true cavity was smaller in patients with clinical symptoms than in those without (P < 0.05). The interlayer length and the degree of true cavity stenosis were positively correlated with clinical symptoms, while true cavity diameter was negatively correlated with clinical symptoms (P < 0.05). The consistency between SISMAD classification by CTA and the clinical results was 0.784 (95%CI: 0.577-0.991), and the accuracy was 84.38% (P < 0.05).

CONCLUSION

CTA has high accuracy in the diagnosis and classification evaluation of SISMAD, and the interlayer length, diameter of true cavity, and degree of true cavity stenosis as the measured parameters of CTA are helpful to evaluate the clinical symptoms of patients.

Clinical characteristics and misdiagnosis of spontaneous isolated superior mesenteric artery dissection

Background

Spontaneous isolated superior mesenteric artery (SMA) dissection (SISMAD) is a rare disease with a potentially fatal pathology. Due to the lack of specificity of clinical characteristics and laboratory tests, misdiagnosis and missed diagnosis are often reported. Therefore, the aim of this study was to investigate the clinical characteristics and misdiagnosis of SISMAD.

Methods

In a registry study from January 2013 to December 2020, 110 patients with SISMAD admitted to the First Affiliated Hospital of Wenzhou Medical University were enrolled. Descriptive methods were used to analyse clinical characteristics, laboratory data, diagnostic method or proof, misdiagnosed cases, plain computed tomography (CT) findings and dissection features. To study the relationship between dissection features and treatment modality, the selected patients were classified into the conservative group (n = 71) and the non-conservative group (n = 39). The Chi-square test and Student’s t-test were used to compare the conservative and non-conservative groups.

Results

One hundred ten patients with SISMAD, including 100 (90.9%) males and 10 (9.1%) females, with a mean age of 52.4 ± 7.6 years, were enrolled in the study. Relevant associated comorbidities included a history of hypertension in 43 cases (39.1%), smoking in 46 cases (41.8%), and alcohol consumption in 34 cases (30.9%). One hundred four patients (94.5%) presented with abdominal pain. Abnormalities in the C-reactive protein lever, white blood cells count and D-dimer lever were the 3 most common abnormal findings. There were 32 misdiagnosis or missed diagnosis. Fourteen cases were misdiagnosed because of insufficient awareness. Twelve cases were misdiagnosed because of disease features. Twenty cases were misdiagnosed as SMA embolism. Among them, There were 15 cases of Yun type IIb SISMAD. Sixty-six patients underwent plain CT. The maximum SMA diameter was 12.1 (11.3–13.1) mm, and the maximum SMA diameter was located on the left renal vein (LRV) plane in 68.2% of cases. Dissection features observed on contrast-enhanced CT (CECT), CT angiography (CTA), or digital subtraction angiography (DSA) showed that there were 70 cases (63.6%) of Yun type IIb SISMAD, the maximum SMA diameter was 13.0 ± 2.4 mm, the location of the maximum SMA diameter was on the LRV plane in 64.5% of cases, and 7.3% of cases were complicated with intestinal obstruction, including bowel necrosis in 3.6% of cases. There were differences between the conservative group and non-conservative groups in the residual true lumen diameter or degree of true lumen stenosis and the presence of intestinal obstruction or bowel necrosis (all P < 0.05).

Conclusion

For SISMAD, misdiagnosis and missed diagnosis were usually caused by insufficient awareness and disease features. SISMAD should be considered in the differential diagnosis of patients presenting with unexplained abdominal pain, especially males, patients in the 5th decade of life, patients with hypertension, and patients with an enlarged SMA diameter or a maximum SMA diameter located on the LRV plane on plain CT. Mesenteric CTA or CECT should be recommended for the investigation of these conditions.