Diffusion-weighted MRI of malignant pleural mesothelioma: preliminary assessment of apparent diffusion coefficient in histologic subtypes

Our plain-English summary of Diffusion-weighted MRI of malignant pleural mesothelioma: preliminary assessment of apparent diffusion coefficient in histologic subtypes, by R.R. Gill, S. Umeoka, H. Mamata, et al (AJR. American Journal of Roentgenology, 2010).

The study

• Authors: R.R. Gill, S. Umeoka, H. Mamata, T.R. Tilleman, P. Stanwell, R. Woodhams, R.F. Padera, D.J. Sugarbaker, H. Hatabu
• Journal: AJR. American Journal of Roentgenology
• Published: 2010;195(2):W125-30
• Cited by: 67 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: The purpose of this study was to prospectively assess, in the evaluation of patients with suspected malignant pleural mesothelioma (MPM), apparent diffusion coefficient (ADC) values derived from diffusion-weighted images obtained with a free-breathing single-shot spin-echo echo-planar imaging sequence and to correlate the ADC values with the three histologic subtypes of MPM.

Subjects And Methods: Sixty-two patients with a known pleural abnormality and clinical findings suggestive of MPM underwent diffusion-weighted 3-T MRI and ADC calculation. The pathologic diagnosis was confirmed by surgical procedure. ADC values were correlated with the histologic subtypes of MPM. Statistical analysis was performed with analysis of variance and the Student's t test.

Results: Fifty-seven patients had MPM. Forty of the tumors were epithelioid, 11 were biphasic, and six were sarcomatoid. The other five patients had pleural thickening (two patients), metastatic adenocarcinoma (one patient), chronic inflammation (one patient), and malignant lymphoma (one patient). Because of image distortion, the diffusion-weighted images and ADC maps were not satisfactory for assessment in seven cases. The ADC values of MPM were 1.31 +/- 0.15 x 10(-3) mm(2)/s for the epithelioid, 1.01 +/- 0.11 x 10(-3) mm(2)/s for the biphasic, and 0.99 +/- 0.07 x 10(-3) mm(2)/s for the sarcomatoid subtypes of MPM. The ADC of the epithelioid subtype was statistically significantly higher than that of the sarcomatoid subtype (p < 0.05). The ADC in the two cases of benign plaque was 0.85 +/- 0.17 x 10(-3) mm(2)/s.

Conclusion: The ADC values of epithelioid mesothelioma are higher than those of sarcomatoid mesothelioma. There is no significant difference between the ACD values of biphasic and those of sarcomatoid MPM.

In plain English

This preliminary study tested whether diffusion-weighted 3-T MRI could tell apart the three tissue subtypes of malignant pleural mesothelioma: epithelioid, biphasic and sarcomatoid. It did not examine asbestos exposure. Sixty-two patients with a pleural abnormality and suspected mesothelioma were scanned between June 2008 and January 2009. Diagnoses came from 38 pleural biopsies, 16 extrapleural pneumonectomies, seven pleurectomies, and one examination of cells in pleural fluid. Fifty-seven had mesothelioma (40 epithelioid, 11 biphasic, six sarcomatoid). The scan measure, called the apparent diffusion coefficient (ADC), could be calculated for 50 of them. Average ADC was 1.31 for epithelioid, 1.01 for biphasic and 0.99 for sarcomatoid tumors (in units of 10−3 mm2/s). Epithelioid values were statistically significantly higher than both other subtypes. Biphasic and sarcomatoid values did not differ significantly. Two benign pleural plaques averaged 0.85, but with only two cases no statistical analysis was done. The authors concluded that the difference between the epithelioid and sarcomatoid subtypes may serve as an imaging marker. They noted that the measured areas on the scans could not be matched to biopsy sites and that biphasic cases were few.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Prospective imaging (diagnostic MRI) study comparing scan measurements with tissue diagnosis
• Who was studied: 62 patients (51 men, 11 women; mean age 64, range 30 to 91) with a known pleural abnormality and suspected malignant pleural mesothelioma, enrolled June 2008 to January 2009; the authors are from Brigham and Women's Hospital, Boston
• Exposure: No asbestos exposure was assessed. The patients underwent diffusion-weighted 3-T MRI with calculation of the apparent diffusion coefficient (ADC).
• Main results:
  • Diagnoses were made by extrapleural pneumonectomy (16), pleurectomy (7), pleural biopsy (38), and in one patient by cytologic examination of pleural fluid obtained by thoracentesis
  • 57 of the 62 patients had malignant pleural mesothelioma: 40 epithelioid, 11 biphasic, 6 sarcomatoid
  • The other 5 patients had two benign pleural plaques, one nonspecific chronic inflammation, one metastatic pleural tumor and one malignant lymphoma
  • ADC could not be calculated in 7 of the 57 mesothelioma cases; 50 were measured (35 epithelioid, 10 biphasic, 5 sarcomatoid)
  • Average ADC in the mesothelioma subtypes was 1.31 ± 0.15 (SD) × 10−3 mm2/s for epithelioid, 1.01 ± 0.11 × 10−3 mm2/s for biphasic, and 0.99 ± 0.07 × 10−3 mm2/s for sarcomatoid
  • Epithelioid ADC was statistically significantly higher than biphasic (p = 2.48 × 10−4) and sarcomatoid (p = 8.14 × 10−5)
  • There was no statistically significant difference between biphasic and sarcomatoid ADC values (p = 0.095)
  • At a threshold of 1.1 × 10−3 mm2/s, sensitivity, specificity and accuracy for telling epithelioid from sarcomatoid tumors were 60%, 94% and 84%
  • In the two benign pleural plaques, average ADC was 0.85 ± 0.17 × 10−3 mm2/s, lower than all mesothelioma subtypes
• The authors' conclusion: The authors concluded, from this preliminary study, that ADC is higher in epithelioid than in sarcomatoid mesothelioma, and that this difference may serve as a surrogate imaging biomarker
• Limitations the authors state:
  • The locations measured on the ADC maps could not be matched with biopsy locations
  • The number of patients with the biphasic subtype was relatively small
  • The free-breathing scan technique can introduce errors in ADC calculation due to image misregistration
  • Only two benign plaque cases, so statistical analysis was not possible for them

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Diffusion-Weighted MRI, Pleural Mesothelioma, Histological Subtype, Epithelioid, Biphasic Mesothelioma, Sarcomatoid, Pleural Thickening, Adenocarcinoma.

Related studies

• Malignant pleural mesothelioma: visual assessment by using pleural pointillism at diffusion-weighted MR imaging — J. Coolen, F. De Keyzer, et al. (2015)
• Robust Cell Detection and Segmentation for Image Cytometry Reveal Th17 Cell Heterogeneity — T. Tsujikawa, G. Thibault, et al. (2019)
• Combined diffusion-weighted and gadolinium-enhanced MRI can accurately predict the peritoneal cancer index preoperatively in patients being considered for cytoreductive surgical procedures — R.N. Low, R.M. Barone (2012)
• Accuracy of pleural biopsy for the diagnosis of histologic subtype of malignant pleural mesothelioma: Necropsy-based study of 134 cases — P.G. Barbieri, D. Consonni, et al. (2022)
• Therapeutic outcome according to histologic subtype in 121 patients with malignant pleural mesothelioma — G.L. Ceresoli, L.D. Locati, et al. (2001)
• Survival by Histologic Subtype of Malignant Pleural Mesothelioma and the Impact of Surgical Resection on Overall Survival — V. Verma, C.A. Ahern, et al. (2018)

Browse more research in AJR. American Journal of Roentgenology, or return to medical research.