Anomalous Systemic Artery to the Non-Sequestrated Lung: Multi-Slice Computed Tomography Features

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Anomalous Systemic Artery to the Non-Sequestrated Lung: Multi-Slice Computed Tomography Features

Rare congenital lung anomalies can be challenging to diagnose, but new research highlights how advanced imaging is demystifying one little-known condition: anomalous systemic artery to the non-sequestrated lung (ASANSL). This condition—where an abnormal artery from the body’s main circulation feeds a normal, connected part of the lung—was once classified as “Pryce type I sequestration,” but a team of radiologists from Shandong, China, has used multi-slice computed tomography (MSCT) to clarify its features and improve care.

What Is ASANSL?

ASANSL is a rare birth defect involving an anomalous systemic artery (ASA)—a blood vessel from the body’s high-pressure systemic circulation (usually the descending aorta)—that supplies blood to a section of the lung that remains connected to the main airway (bronchus). This distinguishes it from true pulmonary sequestration, where the lung tissue is disconnected from the airway and relies on its own abnormal blood supply.

For decades, ASANSL was confused with other conditions, going by names like “pseudosequestration” or “systemic artery to the left lower lobe.” The researchers behind the new study argue “anomalous systemic artery to the non-sequestrated lung” is the most accurate term—it captures both the abnormal artery and the fact that the lung tissue is normal and connected, not sequestered.

The Study: How MSCT Reveals ASANSL

To better understand ASANSL, researchers from the Shandong Medical Imaging Research Institute (Cheeloo College of Medicine, Shandong University), Jinan Shizhong District Hospital, Liaocheng Third People’s Hospital, and Shandong Provincial Hospital reviewed data from 15 patients diagnosed with ASANSL who underwent contrast-enhanced MSCT—a type of CT scan that uses dye to highlight blood vessels.

The team analyzed three key factors:

  1. Origin of the anomalous artery: Where the ASA branched from.
  2. Lung segments supplied: Which parts of the lung the ASA fed.
  3. Parenchymal changes: Damage to the lung tissue (e.g., inflammation, congestion) from high-pressure blood flow.

Key Findings: Who Does ASANSL Affect?

All 15 patients had two defining features:

  • The ASA originated from the descending aorta (the large blood vessel that carries blood from the heart to the lower body).
  • The lung tissue fed by the ASA had normal bronchial connections—meaning it was still linked to the main airway (unlike true sequestration).

Most cases (13 out of 15) involved the left lower lung (LLL), with two affecting the right lower lobe (RLL). For the LLL:

  • 12 patients had the ASA supplying all basal segments (the bottom, most common area affected).
  • 3 patients had the ASA supplying only some segments of the LLL or RLL.

Lung tissue changes varied:

  • 3 patients had normal parenchyma (no visible damage).
  • 12 patients showed signs of mild injury from high systemic pressure, including ground-glass opacity (a hazy area on CT scans indicating congestion), atelectasis (collapsed lung tissue), or bronchiectasis (widened, damaged airways).

Treatment Options for ASANSL

The study also outlined how patients were managed:

  • 5 patients: Underwent surgery to tie off the ASA and remove the affected lobe (lobectomy).
  • 1 patient: Chose therapeutic embolization—a less invasive procedure where tiny coils block the abnormal artery.
  • 9 patients: Opted for watchful waiting, with regular follow-up scans to monitor the condition.

Why MSCT Is a Game-Changer for Diagnosis

In the past, doctors relied on angiography (injecting dye into blood vessels) to diagnose ASANSL—a risky, invasive procedure. The new research confirms MSCT is a safer, more effective alternative:

  • Non-invasive: No needles or dye injections (beyond the contrast used in the scan).
  • Comprehensive: Shows the ASA, its origin, the lung segments it feeds, and any tissue damage in one scan.
  • Treatment planning: Helps doctors decide whether to operate, use embolization, or monitor the condition.

Why This Research Matters

ASANSL is easy to miss or misdiagnose, but this study does two critical things:

  1. Clarifies terminology: By standardizing the name to “anomalous systemic artery to the non-sequestrated lung,” it reduces confusion among doctors.
  2. Validates MSCT: Proves that advanced imaging can replace invasive tests for diagnosis—making care safer and more accessible.

Conclusion

For patients with ASANSL and the clinicians who treat them, this research is a milestone. It confirms that MSCT is a reliable, non-invasive tool for diagnosing this rare condition and planning treatment. Most importantly, it shines a light on a misunderstood anomaly—helping more people get the care they need.

References

  1. Pryce DM. Lower accessory pulmonary artery with intralobar sequestration of lung; a report of seven cases. J Pathol Bacteriol 1946;58:457–467. doi: doi.org/10.1002/path.1700580316
  2. Abe T, Mori K, Shiigai M, et al. Systemic arterial supply to the normal basal segments of the left lower lobe of the lung–treatment by coil embolization–and a literature review. Cardiovasc Intervent Radiol 2011;34:S117–S121. doi: doi.org/10.1007/s00270-010-9798-x
  3. Gormez A, Ozcan HN, Oguz B, et al. Rare presentation of pseudosequestration in childhood: CT and CT angiography findings. Clin Respir J 2017;11:113–116. doi: doi.org/10.1111/crj.12295
  4. Kang B, Ma Y, Li K, et al. Anomalous systemic artery to the non-sequestrated lung: multi-slice computed tomography features. Chin Med J 2020;133:2259–2260. doi: doi.org/10.1097/CM9.0000000000000965

The authors confirmed all patients gave consent for their data and images to be used in the study. No conflicts of interest were reported.

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