Medical Image of the Month: Hampton Hump and Palla Sign

Figure 1. A chest radiograph demonstrates a wedge-shaped opacity in the right lung base (red circle) and enlargement of the right descending pulmonary artery branch (blue arrow) consistent with a Hampton hump and Palla sign, respectively.

Figure 2. A computed tomography angiogram (CTA) of the chest in a lung window demonstrates a wedge-shaped opacity in the right middle lobe consistent with a Hampton hump (red circle).

Figure 3. A CTA of the chest demonstrates an embolus in the right main pulmonary artery which appears slightly dilated (red circle).

Figure 4. A CTA of the chest demonstrates extension of the pulmonary embolus into the right lower lobe pulmonary arterial branch (blue circle) along with a right middle lobe pulmonary infarction (red circle) which is better demonstrated in Figure 2.

A 51-year-old lady presented to emergency room with acute, severe, right-sided pleuritic chest pain, mild cough and dyspnea at rest. She underwent a lumbar spine laminotomy and foraminotomy twelve days prior to her presentation with limited mobility after her operation. On examination, she was tachypneic and tachycardic. Her blood pressure and oxygen saturations on room air were normal. Chest auscultation revealed a few crackles in the right lung base. There was no pedal edema or calf tenderness.

A chest radiograph demonstrated a right lower lobe wedge-shaped opacity along with right hilar prominence (Figure 1). She was initially diagnosed with a right lower lobe pneumonia and was admitted to step-down unit for further management. However, her history, clinical examination, and chest radiograph findings suggested the high likelihood a pulmonary embolism. A computed tomography angiogram (CTA) of the chest confirmed the diagnosis of a pulmonary embolism (Figures 2-4).

Based her clinical presentation and radiology results, the patient was diagnosed with a sub-massive pulmonary embolism (PE). She was treated with an intravenous heparin drip. She was hemodynamically stable throughout the hospital admission. Her echocardiogram showed no evidence of right ventricular strain. Eventually, she was transitioned to oral anticoagulation and was discharged home in good condition.

Discussion

The wedge-shaped right lower lobe opacity and right hilar prominence correspond to a Hampton hump and Palla sign, respectively. A Hampton hump represents a pulmonary infarction secondary to PE, and it was named by the radiologist Aubrey Hampton in 1940 (1). The Palla sign is an enlarged right descending pulmonary artery, an observation made in 1983 by a radiologist, Antonio Palla (2). Both signs can be seen on chest radiography and may aid in the diagnosis of a PE.

Although these radiologic findings of PE are rare, practicing physicians should be aware of these findings as they can be extremely helpful and expediate the diagnosis of a PE. On the other hand, misinterpretation of these findings can lead to a delay in the diagnosis of other significant chest pathologies.

Abdulmonam Ali MD and Naga S Sirikonda MD

SSM Health

Mount Vernon, IL USA

References

1. Hampton AO, Castleman B. Correlation of postmortem chest teleroentgenograms with autopsy findings with special reference to pulmonary embolism and infarction. Am J Roentgenol. 1940;43:305–26.
2. Palla A, Donnamaria V, Petruzzelli S, Rossi G, Riccetti G, Giuntini C. Enlargement of the right descending pulmonary artery in pulmonary embolism. AJR Am J Roentgenol. 1983;141:513-7. [CrossRef] [PubMed]

Cite as: Ali A, Sirikonda NS. Medical image of the month: Hampton hump and Palla sign. Southwest J Pulm Crit Care. 2019;19(5):144-5. doi: https://doi.org/10.13175/swjpcc041-19 PDF

Medical Image of the Week: Pulmonary Infarction- the “Reverse Halo Sign”

Figure 1. CT Chest with contrast. Two different levels in the same patient displayed on mediastinal windows. Several triangular shaped subpleural lesions with annular peripheral solid appearance are depicted, better characterized in the lung windows below (yellow arrows). Note the partial filling defect (red arrow on B), indicating a non-occlusive thrombus(arrow). Bilateral pleural effusions are also identified.

Figure 2. CT Chest with contrast, lung window corresponding to the levels in Figure 1 above. Note the triangular shaped subpleural lesions with peripheral solid appearance and ground glass center, characteristic of the atoll sign (arrows). As above, bilateral pleural effusions are present.

Pulmonary infarction is a known complication of pulmonary embolism (PE), a common disorder that results in 100,000-200,000 deaths annually in the United States. Computed tomography (CT) is the first-line modality to assess the pulmonary circulation with the ability to directly the visualize pulmonary emboli as well as pleuro-parenchymal abnormalities.

The appearance of a pulmonary infarct varies depending on the degree of ischemic injury in the setting of a dual blood supply to the lung. Infarcts occur more commonly in the periphery of the lung, given, the alternate blood supply by the bronchial arteries, is not as efficient as it is centrally. This location is also favored by the more common occurrence after occlusion of small peripheral arteries of 3 mm or less in caliber.

On CT lung infarcts can take the can take the “reverse halo” sign, also known as the “atoll” sign configuration, representing a focal area of decreased enhancement, and surrounding solid appearance. In the case of lung infarcts, the lesions typically have a broad pleural base triangular form with apex toward the hilum (1). Pathologically this corresponds to a hemorrhagic consolidation. The center of the lesion appears to correspond to aerated non-infarcted lung coexisting side by side with infarcted lung in the same lobule. The broad-based configuration is explained by the fan shaped distribution of the arteries as they extend out into the periphery. The convex border reflects the extravasated blood within the infarcted lung. Once the hemorrhage reabsorbs, the infarct heals completely or may leave behind a linear band of scarring.

From the imaging stand point, the reverse halo sign initially described in cryptogenic organizing pneumonia, has also been noted in patients with fungal disease, granulomatosis with polyangiitis, sarcoidosis and neoplastic disease among others (2).

George R Wu MS IV¹, Berndt Schmit MD², Veronica Arteaga MD², and Diana Palacio MD²

¹Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ USA

²Division of Thoracic Imaging, University of Arizona, Tucson, AZ USA

References

1. He H, Stein MW, Zalta B, Haramati LB. Pulmonary infarction: spectrum of findings on multidetector helical CT. J Thorac Imaging. 2006;21(1):1-7. [CrossRef] [PubMed]
2. Godoy MC, Viswanathan C, Marchiori E, et al. The reversed halo sign: update and differential diagnosis. Br J Radiol. 2012;85(1017):1226-35. [CrossRef] [PubMed]

Cite as: Wu GR, Schmit B, Arteaga V, Palacio D. Medical image of the week: pulmonary infarction- the “reverse halo sign”. Southwest J Pulm Crit Care. 2017;15(4):162-3. doi: https://doi.org/10.13175/swjpcc124-17 PDF 

Medical Image of the Week: PE with Infarct and Pulmonary Cavitation

Figure 1. Panels A & B: thoracic CT scan showing multiple pulmonary emboli (arrows). Panel C: frontal chest radiograph showed extensive left lung opacification most dense in the left upper lobe. Panel D: frontal chest radiograph taken 3 weeks later showing mild volume loss of the left upper lobe with a large lucency suggestive of cavitation (arrow). Panel E: thoracic CT scan confirming the cavitation.

A 49 year old man with a history of COPD presented to the ER with the sudden onset of chest pain at 3:30 AM waking him from sleep. His pain was left sided, felt like broken ribs, and was worse with deep inspiration. He acknowledged some shortness of breath which was worse over baseline for the past couple days without cough or hemoptysis. The patient was tachycardic but comfortable with SpO2 saturation 98% on 2 liters. He had trace edema and pleurisy. Laboratory evaluation was unremarkable except for a WBC count 13,000 X 10⁶ cells/L. Chest x-ray was unremarkable but thoracic CT scan showed pulmonary emboli (PE) involving left upper and lower lobar arteries (Figure 1A and 1B, arrows). Anticoagulation was started and the patient experienced increasing shortness of breath, worsening oxygenation and fever to 102ºF. On Day 2, frontal chest radiograph showed extensive left lung opacification most dense in the left upper lobe (Figure 1C). Hemoglobin dropped from 12 to 9.8 g/dL suggesting alveolar hemorrhage. He improved over the next week but low grade fevers persisted and a chest x-ray taken 3 weeks later showed mild volume loss of the left upper lobe with a large lucency suggestive of cavitation (Figure 1D, Arrow). Thoracic CT confirmed a cavitary lesion in the left apex in the region of prior thrombus with adjacent consolidated atelectasis within a background of emphysema (Figure 1E).  The patient was lost to follow up after 6 months of anticoagulation.

Pulmonary infarction is relatively uncommon, occurring in less than 10% of PE, due to dual and collateral blood supply to the lung. Cavitary infarcts are even less common (4% in autopsy studies) and are more likely in those with pulmonary venous hypertension (1). Cavitary infarcts are more likely to occur when the infarct size in larger than 4 cm and most often occurs in the mid and upper lung zones. Despite alveolar hemorrhage, anticoagulation should be continued.

Kenneth S. Knox, MD and Veronica A. Arteaga, MD

Divisions of Pulmonary and Critical Care Medicine and Thoracic Imaging

University of Arizona

Tucson, AZ

Reference 

1. Libby LS, King TE, LaForce FM, Schwarz MI. Pulmonary cavitation following pulmonary infarction. Medicine (Baltimore). 1985;64(5):342-8. [CrossRef] [PubMed]

Reference as: Knox KS, Arteaga VA. Medical image of the week: PE with infarct and pulmonary cavitation. Southwest J Pulm Crit Care. 2014;9(6):333-4. doi: http://dx.doi.org/10.13175/swjpcc158-14 PDF