Paradoxical signal pattern of mediastinal cysts on T2-weighted MR imaging: phantom and clinical study

Development of estimation method for T1 and T2 values using the relaxivity of contrast agent and coagulant for a magnetic resonance imaging phantom

The T1 and T2 values of magnetic resonance imaging phantoms used by researchers should be equivalent to those of the target tissue. However, this is difficult to achieve because of variations in the phantoms depending on the type and concentration of contrast agents and coagulants. The aim of this study was to elucidate the utility of a determination equation derived using the relaxivity of the contrast agent and coagulant. We prepared phantoms using 0.05-10 mmol L-1 contrast agent (Gadovist®; Bayer Yakuhin, Ltd., Osaka, Japan) and 0.1-5.0 wt% agar (agar, powder [010-15815]; Fujifilm Wako Pure Chemical Corporation, Osaka, Japan) and measured their T1 and T2 values. Determination equations for T1 and T2 values were derived using the relaxivity calculated from the T1 and T2 values of the contrast agent and coagulant. Subsequently, the determined values were compared with the measured values. The error rate of the determined T1 and T2 values were 7.66 ± 6.60% and 5.66 ± 4.05%, respectively, with correlation coefficients of 0.996 and 0.999. These results indicate that this method enables easy and highly accurate estimation of T1 and T2 values in MRI phantoms.

Pericardial cyst unveiling: a case of unusual chest symptoms in a young woman with a family history of cancer: a case report and review of literature

BACKGROUND

Pericardial cysts, though rare and benign, can present with various clinical symptoms depending on their size and location in the body. The detection of these cysts typically relies on imaging studies for a conclusive diagnosis, with surgical removal being the definitive treatment.

CASE PRESENTATION

This case report details the clinical journey of a 32-year-old Iranian woman with a family history of breast and lung cancer, who experienced left-sided chest pain. Utilizing a combination of clinical history review, mammography, echocardiography, and computed tomography, a precise diagnosis of a 10 cm × 3.5 cm pericardial cyst was achieved. The patient underwent median sternotomy for complete cyst excision.

CONCLUSIONS

While pericardial cysts are often asymptomatic and benign, they can lead to life-threatening complications. Hence, regular follow-up is advised, and in certain instances, minimally invasive interventions or surgery may be necessary.

Chest Magnetic Resonance Imaging: Advances and Clinical Care

Many promising study results as well as technical advances for chest magnetic resonance imaging (MRI) have demonstrated its academic and clinical potentials during the last few decades, although chest MRI has been used for relatively few clinical situations in routine clinical practice. However, the Fleischner Society as well as the Japanese Society of Magnetic Resonance in Medicine have published a few white papers to promote chest MRI in routine clinical practice. In this review, we present clinical evidence of the efficacy of chest MRI for 1) thoracic oncology and 2) pulmonary vascular diseases.

Mature mediastinal bronchogenic cyst with left pericardial defect: A case report

BACKGROUND

Mediastinal bronchogenic cysts and pericardial defects are both rare. It is extremely rare that both occur simultaneously. To the best of our knowledge, this is the first case of a coexistent bronchogenic cyst and pericardial defect reported in China. We performed a literature review and found a relationship between bronchogenic cysts and pericardial defects, which further revealed the correlation between the bronchus and pericardium during embryonic development.

CASE SUMMARY

A 14-year-old boy attended a local hospital for ankylosing spondylitis. Chest radiography showed an enhanced circular-density shadow near the left mediastinum. The patient had no chest symptoms and the physical examination was normal. Because of the mediastinal occupation, the patient visited our department of chest surgery for further treatment. During surgery, a left pericardial defect was observed. The bronchogenic cyst was removed by thoracoscopic surgery, but the pericardial defect remained untreated, and a satisfactory outcome was achieved after the operation. The patient was diagnosed with a mediastinal tumor. The pathological diagnosis of the tumor was a bronchogenic cyst.

CONCLUSION

This case further reveals the correlation between the bronchus and pericardium during embryonic development.

Detection of pericardial flow in black blood-prepared T2 HASTE sequence imaging: Differentiation between pericardial diverticulum and cyst

Pericardial diverticulum is a focal herniation of the pericardium. It is differentiated from a pericardial cyst by the presence of communication with the pericardial cavity. Radiological differentiation between the diverticulum and cyst via computed tomography is difficult unless changes in size are identified with different body positions in additional scans. Herein we describe a case of pericardial diverticulum that was successfully diagnosed via the detection of internal pericardial flow in black blood-prepared T2 half-Fourier acquisition single-shot turbo spin-echo magnetic resonance imaging. Detection of a flow void in the pericardial sac may be a definitive magnetic resonance imaging finding in the diagnosis of pericardial diverticulum.

Mediastinal and Pleural MR Imaging: Practical Approach for Daily Practice

Radiologists in any practice setting should be prepared to use thoracic magnetic resonance (MR) imaging for noncardiac and nonangiographic applications. This begins with understanding the sequence building blocks that can be used to design effective thoracic MR imaging protocols. In most instances, the sequences used in thoracic MR imaging are adapted from protocols used elsewhere in the body. Some modifications, including the addition of electrocardiographic gating or respiratory triggering, may be necessary for certain applications. Once protocols are in place, recognition of clinical scenarios in which thoracic MR imaging can provide value beyond other imaging modalities is essential. MR imaging is particularly beneficial in evaluating for benign features in indeterminate lesions. In lesions that are suspected to be composed of fluid, including mediastinal cysts and lesions composed of dilated lymphatics, MR imaging can confirm the presence of fluid and absence of suspicious enhancement. It can also be used to evaluate for intravoxel lipid, a finding seen in benign residual thymic tissue and thymic hyperplasia. Because of its excellent contrast resolution and potential for subtraction images, MR imaging can interrogate local treatment sites for the development of recurrent tumor on a background of post-treatment changes. In addition to characterization of lesions, thoracic MR imaging can be useful in surgical and treatment planning. By identifying nodular sites of enhancement or areas of diffusion restriction within cystic or necrotic lesions, MR imaging can be used to direct sites for biopsy. MR imaging can help evaluate for local tumor invasion with the application of "real-time" cine sequences to determine whether a lesion is adherent to an adjacent structure or surface. Finally, MR imaging is the modality of choice for imaging potential tumor thrombus. By understanding the role of MR imaging in these clinical scenarios, radiologists can increase the use of thoracic MR imaging for the benefit of improved decision making in the care of patients. ^©RSNA, 2018.