Rare diseases and cancers can present difficulties for those working to arrive at a conclusive diagnosis. Nonspecific symptoms, fluid buildup and inconclusive scans can all obfuscate resolution and results from a patient’s images. Beyond these common issues radiologists face each day, working to properly identify and stage a disease among many possibilities can be a complex task. For example, lung cancer and malignant pleural mesothelioma affect the same thoracic region, yet are distinct malignancies with often drastically different standards of care and options available upon diagnosis.
Differentiating rare diseases from more common cancers can be so complex because of their rarity. Reading lab results and viewing scans naturally leads specialists to look for the most common answer, which can ultimately delay a proper diagnosis.
Specifically in the case of malignant pleural mesothelioma and other aggressive cancers, early detection and moving quickly through the diagnostic process can be crucial. Patients and specialists are often left navigating limited treatment options and an average prognosis of only 15 months, making accurate staging and an early diagnosis even more sensitive than diagnosing other malignancies. Through efficient and accurate imaging, radiologists and specialists can work together to accurately reach a conclusive, differential diagnosis upon which to move forward in treating a patient at an earlier stage of the disease.
With cases of pleural mesothelioma that present with general symptoms like breathlessness, chest pain and weight loss, a comprehensive approach typically begins with chest x-rays. Common abnormalities noted from x-rays can be pleural effusions, as well as pleural plaques in some cases. As with many other thoracic conditions, one of the most useful results from this stage of imaging is gauging the level of fluid and edemas present. Other cues to look for are loss of hemithoracic volume, nodular pleural thickening, irregular fissural thickening or a localized mass lesion.
Ultrasound and thoracoscopy have both been proven to be effective when used for highly targeted areas of the diagnostic process. Ultrasound is beneficial when measuring volume and location of pleural effusions, particularly during the evaluation during or prior to biopsy or thoracentesis. When pleural mesothelioma is suspected through data and prior imaging, a thoracoscopy can be highly beneficial, with low rates of complication. These tools are valuable on their own, yet their most effective uses are in conjunction with other imaging data as a means of assisting and confirming results.
While ultrasound can be useful in confirming a suspected diagnosis, CT, MRI and PET scans are typically the next step and most effective tests utilized in reaching a conclusive diagnosis for pleural mesothelioma after x-rays. In most cases, CT scans are the most important and often most helpful for radiologists to best determine the scope and extent of the situation, as well as guide specialists in CT-assisted biopsies. Evaluation of CT results specifically alongside other tests are necessary for proper staging, which is crucial for patients as treatment options are often severely limited and have small time frames of opportunity before the malignancy is too far gone. Some features present in CT results can include mapping the tumor progression into the chest wall, mediastinum and diaphragm, pleural thickening and interlobar fissural nodularity.
For complex malignancies that can be difficult to properly diagnose and even more difficult to treat, CT results do not always provide all the information needed for specialists to present options to patients. Following up CT results with both PET scans and MRIs can be beneficial in helping stage the disease and identifying possible metastases. PET scans are specifically useful in following up where CT scans often fall short and can determine how pronounced and advanced into the chest wall and diaphragm the primary malignancy has invaded and the extent of any extrathoracic metastasis for patients eligible for surgical options. Yet PET scans still have some drawbacks, as prior pleurodesis and inflammatory disorders can provide false positives and offer poor spatial resolution.
Once patients have been properly diagnosed with initial staging determined, MRIs provide the clearest results for specialists while evaluating a patient’s fitness for surgical resection. Offering the greatest spatial and contrast resolution, MRIs have been best utilized in assessing the extent of invasion, metastasis and morphological features of the malignancy prior to surgery. The efficacy of an MRI alone is greatly enhanced and accurate at assisting with staging and assessing tumors for possible resection and surgical eligibility when functional data via the use of contrast agents are utilized to discern between benign and malignant pleural disease.