CASE 10494 Published on 16.03.2013

Lung torsion after lobectomy

Section

Chest imaging

Case Type

Clinical Cases

Authors

Skondras E, Kraniotis P, Tsota I

Rio 26504 Patras, Greece;
Email:vaggoul@gmail.com
Patient

67 years, female

Categories
Area of Interest Lung, Respiratory system ; Imaging Technique CT
Clinical History
A 67-year-old female patient with left lower lobe lung cancer underwent lobectomy. The initial post-surgical chest radiograph was unremarkable. 12 hours post extubation she developed hypoxaemia and haemoptysis. Chest radiograph was initially performed, followed by MDCT to confirm the diagnosis.
Imaging Findings
The initial routine AP chest radiograph showed post-surgical changes in the left lung.
After 12 hours, the follow-up chest radiograph revealed unexpected near complete opacification of the left hemithorax and fluid collection (Figure 1).
MDCT revealed extensive consolidation and peripheral interlobular smooth septal thickening, thus creating a crazy-paving pattern, with no parenchymal enhancement (Figures 2a, b). Enlargement of the left upper lobe (LUL) and clockwise rotation around its axis was noted (Figure 2c). There was cut-off of the left main pulmonary artery at the level of the hilum with intense enhancement of the bronchial artery (Figure 2d). Thick slab MIP demonstrated complete loss of pulmonary vasculature as opposed to the right lung (Figure 2d). Occlusion of the left mainstem bronchus was also present, better delineated in MinIP post-processing images (Figure 2e). Virtual bronchoscopy revealed the orifice mismatch between the left and right mainstem bronchus (fish-mouth bronchus) (Figure 2f).
Discussion
Lung torsion is defined as the rotation of a lobe (or the complete lung) around its hilar axis. The rotational threshold for complete and incomplete torsion is 180o [1]. Predisposing conditions for torsion are a mobile lobe or lung, either due to iatrogenic causes (lobectomy, transplantation) (Figure 3) or spontaneously (anatomic variations, extrapulmonary pathology such as pleural effusion) and traumatic. Rare causes for torsion have been described (i.e. extralobar sequestration torsion) [12]. The torsive lung creates a trifold compromise in airways, arterial blood supply and the venous-lymphatic drainage [2] due to lumen kinking.

The incidence of lung torsion is low (0.09-0.4%) [3], however, it is an important post-operative consideration not least because of its rather non-specific clinical presentation. A high index of clinical suspicion is required and imaging is the next step towards a definite diagnosis. Prompt treatment with thoracotomy and detorsion is essential for lobe salvage.

Key radiographic findings consist of inappropriate hilar displacement, rapid opacification of ipsilateral lobe following trauma/surgery, marked change in position of opacified lobe on sequential radiographs, unusual position of a collapsed lobe, a reticular pattern from venous congestion and larger residual lung volume than expected from compensatory postoperative emphysema alone [4, 5].

CT findings include consolidation, smooth interlobular septal thickening and ground glass opacity due to venous congestion, loss of parenchymal enhancement after CM administration, perihilar bronchial distortion or obstruction and alteration of normal relationship between vessels [2, 6, 7].

Bronchoscopy and conventional angiography have been traditionally used for definitive diagnosis in ambiguous cases. However, MDCT with image postprocessing (MIP, minIP, Virtual Bronchscopy) produces excellent angiographic and bronchoscopic views respectively, thus streamlining the diagnostic algorithm [8].

Once diagnosed, lung torsion is a medical emergency. The optimal therapeutic approach remains controversial [8]. The decision for detorsion or lobectomy usually depends on the viability of the torsive lung which is better appreciated after open thoracotomy. Detorsion offers lung salvage but if inappropriate, it may lead to rethoracotomy and lobectomy. Furthermore, detorsion is more often associated with vascular complications (arterial embolism) and grave outcome [9].

Apart from early diagnosis, imaging is useful in differentiating other early or late post lobectomy complications (pneumonia, vascular occlusion etc.) [3, 10, 11] which may have similar clinical presentation.

Lung torsion, although a rare postoperative complication, should not be neglected in the diagnostic algorithm. Radiography may indicate torsion but CT with imaging postprocessing offers definitive diagnosis and prompt treatment, contributing to better overall prognosis.
Differential Diagnosis List
Left upper lobe torsion after left lower lobectomy
Pneumonia
Pulmonary oedema
ARDS
Final Diagnosis
Left upper lobe torsion after left lower lobectomy
Case information
URL: https://eurorad.org/case/10494
DOI: 10.1594/EURORAD/CASE.10494
ISSN: 1563-4086