Malignant pheural mesothelioma, MPM, is a rare, closely related to exposure to asbestos primary pleural malignancy. The incidence rate increasing year by year [1 ~ 4], atypical clinical manifestations of the disease, early diagnosis and treatment than those in difficult imaging examination to discover the best means of disease, CT is currently recognized as the best imaging inspection methods.
1 MPM the CT manifestations
1.1 more than in the surrounding localized malignant pleural, a few in the leaves of the pleura, Chengbian mound-shaped, round or oval soft tissue mass, surface finishing, can also be slightly uneven or lobulated, the majority of the tumor and pleura was obtuse angle, a few may acute angle, and the size of the tumor, the tumor is often large acute angle with the pleura, while the small, mostly obtuse, rarely pedunculated, pedunculated tumor often showed an acute angle and with the position or breathing and movement. Extrapleural layer of fat mass and clear interface, tumor density, tumor calcification even seen, the majority of enhanced scan was homogeneous enhancement, the enhanced value of the average increase 121HU, the larger the tumor enhanced heterogeneous, there are low-density cystic degeneration, hemorrhage and necrosis District, CT can show a tumor 0.5cm. Located in the cleft between the tumor often has leaves oval, smooth edges, uniform or irregular tumor adjacent pleural thickening, nodular surface uneven or changed. May be associated with pleural effusion, rib and other damage or chest wall invasion, and occasionally great mesothelioma can compress the trachea, resulting in atelectasis or mediastinal shift.
1.2 Diffuse
1.2.1 pleural thickening ring is surrounded by any level of the chest wall pleural thickening can be uneven thickness, including the involvement of mediastinal pleura throughout the hemi, or violation of surrounding lung tissue, so that smaller capacity, extensive irregular pleural thickening of the pleura to form a thick shell, was surrounded by armor-like lung, pulmonary gas gap loss, pleural cavity disappeared. Specificity of 100%.
1.2.2 parietal pleural thickening parietal pleural thickening> 1cm [5], specificity 94%.
1.2.3 refers to diffuse pleural thickening or pleural lesions in the upper and lower transverse diameter> 5cm, with a large number of pleural effusion, and mediastinal shift was no fixed form, intercostal space is not widened, narrow thorax to the lower part of the more common chest [ 2,3]. CT is easily detected in pleural effusion, lateral position can be detected <15ml of the liquid [6,7].
1.2.4 crescent irregular soft tissue mass (> 4cm) or within the margin of irregular wavy appearance, reduced pressure in varying degrees in lung tissue, pleural thickening and irregular interface with adjacent lung, pleura and nodules of varying moderately enhanced levels. Precontrast CT value of the 45 ~ 54HU, enhanced CT value of 78.6 ~ 106.2HU, increased 25 ~ 45HU, average 33HU, specificity of 94%. Mesothelioma is sometimes lower in the CT value of the plain with effusion is difficult to distinguish, but mesothelioma is obviously enhanced after injection enhancer, the two can be different.
1.2.5 pleural calcification is less common and rarely calcification within the tumor. Some scholars believe that calcification within the tumor may be the type of MPM osteosarcoma sarcoma degeneration [8] or the performance of MPM of ectopic bone formation [9].
1.2.6 asbestos pleural plaques are the most common manifestation of contact, long-term history of asbestos exposure in patients with pleural plaques visible on the CT slices, calcified pleural plaques which accounted for 67%, 26% transparent plaques [10], also seen round a small number of pulmonary Zhang. Mainly involving the lateral parietal pleura Ministry (the equivalent of 7 to 10 ribs), very few violations of apex, the anterior chest wall and costophrenic angle. HRCT is superior to the detection of pleural plaques and conventional chest CT. Aberle [11] have reported that a group of patients with pleural plaques, conventional CT in the detection rate of 93%, while HRCT was 100%. HRCT also helps pleural plaques and lung nodules, and the identification of EPF. HRCT also the early detection of pleural thickening and the leaves of the plaque.
1.2.7 Round atelectasis caused mainly due to asbestos exposure, is closely related with the occurrence of MPM [12,13], its characteristic comet tail sign of change. Including thickening of the pleura, the external mass and accumulation of bronchovascular bundles extending to the hilum. Diagnostic criteria [14 ~ 16]: (1) round or oval mass, diameter 3.5 ~ 7.0cm, and close to the pleura in the lung periphery; (2) contains blood vessels and bronchi into the mass of bending stripes, and to the lung tumor door side of the edge blur. (3) pleural thickening.
1.2.8 between the invasion and metastasis often leaves pleura, mediastinal pleura violated. Direct violation of the tumor adjacent structures such as mediastinum, pericardium, chest wall, through the posterior mediastinum to the contralateral chest or abdominal cavity through the diaphragm directly to the invasion, it was suspected MPM should be routine, including the upper abdomen scan. Lymphatic, hematogenous metastasis and ribs, vertebrae were damaged in a rare, usually occur late in the course of the disease, late distant metastasis.
1.2.9 CT and pathological relationship between CT and Pathology have a certain relationship between the type of sarcoma that affected 91% of the mediastinal pleura, interlobar pleural involvement in 87%, 48% lung involvement; and epithelial 61%, 35%, 4 %; mixed 65%, 10%, 10%; III in lymph nodes, pericardium, chest wall, no difference in the violation. Generally believed that the violations are usually broader based sarcoma [14].
1.3 MPM CT manifestations Kawashima et al [2] reported 50 cases of MPM CT were as follows: nodular pleural thickening (92%), interlobar pleural thickening (86%), pleural effusion (74%), ipsilateral pleural shrinking (42%), chest wall involvement (18%), mediastinal shift to the contralateral (14%), mesothelioma calcification (12%), rib destruction (10%), subphrenic peritoneal involvement (8%), pericardial effusion (6%), contralateral pleural involvement (4%). Ng et al [15] reported 70 cases of MPM CT showed pleural thickening (94%), pleural effusion (76%), ipsilateral pleural reduced (27%), enlargement (10%), calcified pleural plaques (16%) . CT is the most common signs of unilateral pleural thickening ring, nodular pleural thickening, pleural thickening> 1cm, and mediastinal pleural involvement [15,16].
2 stages
2.1 Butchart staging [17] and Autman staging [18] Ⅰ of: tumor confined to the parietal pleura of the "envelope" (ie involving only the unilateral pleural, lung, pericardium, and diaphragm); Ⅱ period: the tumor violations of the chest wall or mediastinal organs (ie esophagus, heart, opposite pleura), intrathoracic lymph node metastasis; Ⅲ of: tumor invasion through the diaphragm and abdominal, contralateral pleural involvement, chest lymph node metastasis; Ⅳ: distant metastasis .
2.2 Chahinian stage [19] Ⅰ on: T1N0M0; Ⅱ period: T1 ~ 2N1M0 T2N0M0; Ⅲ on: T3 any N1M0; Ⅳ of: T4 any N1M0, M1. Note: T-primary tumor; N-lymph node; M-transfer; T1: only limited to the side of the pleura (parietal pleura, visceral pleura); T2: limited to superficial invasion (diaphragm, chest fascia, the ipsilateral lung fissure); T3: local deep infiltration (chest over chest fascia); T4: extensive direct invasion (contralateral pleura, peritoneum, retroperitoneal); N0 no positive lymph nodes; N1 ipsilateral hilar lymph nodes; N2 mediastinal lymph nodes; N3 contralateral hilar lymph nodes; M0 without metastasis; M1 have bloody or lymph node metastases.
2.3 UICC staging [20] Ⅰ on: T1N0M0 T2N0M0; Ⅱ of: T1N1M0 T2N1M0; Ⅲ period: T3N0M0, T3N1M0, T1N2M0, T2N2M0, T3N2M0; Ⅳ of: any T, N3M0; T4 any N1M0; any T, any N1M1 ; clinical stage as cTNM, pathological stage as pTNM. Both the same standard. Note: T: primary tumor and scope; TX: primary tumor can not be determined; T0: No primary tumor; T1: confined to one side of the primary parietal and (or) visceral pleura; T2: tumor invasion of the ipsilateral lung thoracic vein, diaphragm, or pericardium; T3 tumors invading one of the following: ipsilateral chest wall muscle, ribs, mediastinal organs or tissues; T4: tumor invasion of one of the following: a direct violation of the contralateral pleura, or lung, a direct violation of peritoneal , retroperitoneal, or abdominal organs, neck tissue; N: lymph node; NX: regional lymph nodes can not be determined; N0: No regional lymph node metastasis; N1: ipsilateral bronchopulmonary or hilar lymph node metastasis; N2: ipsilateral mediastinal lymph node metastasis; N3: contralateral mediastinal, internal mammary, supraclavicular or scalene lymph node metastasis; M: metastasis; MX: distant metastasis can not be determined; M0: no (confirmed) distant metastasis; M1: distant metastasis.
2.4 features a variety of MPM is a rare tumor stage, there is no accurate and generally accepted staging. Application to determine whether the surgical tumor stage, prognosis, and to provide more treatment outcomes. Based only on the length of the original course of the disease to determine the surgical indication of mesothelioma, prognosis and treatment results comparing the sub-laws have been completely eliminated, is widely used staging system proposed by Butchart, etc.. Butchart and so currently the most commonly used staging method [21]. But the Butchart staging for primary tumor and metastatic lymph nodes is not accurate enough description, not possible to estimate survival, and the scholars have not talked about staging the tumor, lymph nodes and a description of the transfer (TNM) and only provide information on lymph node involvement, chest wall by invasion of the fuzzy situation. For example, a phase Ⅰ pleural tumors, including small lesions, chest free adhesions, pleural effusion, and those integrated into the thick of the tumor disappeared but there is no violation of the pleural space or contralateral mediastinal pleura who, In addition, the accuracy of the MPM incidence of lymph node metastasis and its effect on prognosis is unclear. The provisions of intrathoracic lymph node metastases in stage Ⅱ and the provisions of the chest lymph node metastasis in stage Ⅲ are empirical. The earliest clinical application of the design and scope of regional lymph node involvement and local invasion situation TNM staging system, stage, etc. Chahinian proposed staging, more accurate than the Butchart staging, but not fully reflect the open heart surgery often see, for example difficult to find T1 tumors involving the parietal and visceral pleura, the diaphragm surface has not been involved, because the MPM is a disseminated disease, where the most frequent tumor in the lower half of the thorax and diaphragm, in order to improve and harmonize MPM staging, the International Union Against Cancer (UICC) TNM staging proposed by another program, compared with the previous solution, T the provisions of more detailed description of lymph node metastasis is directly borrowed is the current internationally accepted non-small cell lung cancer standards, but whether the long-term survival with the relevant regional lymph node involvement, visceral involvement, or invasion depth information is also determined [22]. Therefore, this program also need careful clinical and pathological contrast to affirm or modify. To find a suitable stage remains a difficult task [23].
3 rating (value)
Compared with ultrasound, CT can better observe the tumor location, shape and scope, easier and pleural disease, lung tumor, and other identification of, CT localization biopsy positive rate as high as 85% or more, than the B-and high-wear breast [25,27], CT locate the site of biopsy positive rate, including pleural nodules, pleural> 10mm of regional and mediastinal pleural thickening Department. CT-guided MPM intractable pain [28] and a variety of physical, chemical treatment, is currently a hot research.
In conclusion, chest CT examination in the diagnosis of pleural mesothelioma has an important role, is the most accurate noninvasive method. By showing the degree and extent of disease and conditions involving the thoracic internal organs for disease stage, surgery is to determine the feasibility of the most reliable diagnostic method [30,31], and pleural resection or pleural pneumonectomy patients were followed up in other imaging or clinical recurrence before, CT can often suggest tumor recurrence, for monitoring the recurrence can also be used to determine the efficacy of such treatment is followed up the best way to condition changes. CT and MRI is more economical than, consider a more preferred from the titer [29]. However, the lack of specificity of CT signs, and other identifying pleural lesions seems to be difficult.
