Treatment of thoracic malignancies by radiotherapy is often limited by normal lung tissue's tolerance of the radiation. Nuclear magnetic resonance imaging (MRI) can be used to follow changes in lung tissue and can be repeated serially without adverse effects to the patient. We assessed the usefulness of this technique in 41 male Wister rats, producing pneumonitis in the right lung of each animal by administering 14-Gy irradiation, and using the left lung of each animal as control. Longitudinal and transverse nuclear magnetic resonance (NMR) relaxation times and pulmonary blood flow were measured during the development of pneumonitis. Lungs of representative animals were examined microscopically for lymphocytic foci. Spin-lattice relaxation time (T1) of the irradiated lung increased significantly (P < 0.05) between 60 and 80 days; otherwise it was not different from that of the control (left) lung. For 80 days after treatment spin-spin relaxation time (T2) initially increased compared to that of the control lung, and then it returned to normal values. Pulmonary blood flow had decreased significantly by 60 days (P < 0.05) and remained significantly below control values. Lymphocytic foci had increased to 350% of initial values by Day 80 (P < 0.05) and then quickly decreased to pre-radiation values by Day 100. These results suggest that there is a significant change in the T1 of lung tissue during the development of pneumonitis, which begins at the onset of radiation fibrosis.
Get full access to this article
View all access options for this article.
References
1.
PhillipsT.Pulmonary section—Cardiorespiratory workshop. Cancer Clin Trials1981;4(suppl):45–52.
2.
Van DykeJ, KeanTJ, KanS, RiderWD, FryerCJH. Radiation pneumonitis following large single dose irradiation: A re-evaluation based on absolute dose to lung. Int J Radiat Oncol Biol Phys1981;7:461–467.
3.
PenneyDP, RubinP.Specific early fine structural changes in the lung following irradiation. Int J Radiat Oncol Biol Phys1977;2:1123–1132.
4.
HallEJ. Radiobiology for the radiologist. 2nd ed. New York: Harper and Row, 1978.
5.
AdamsonIYR, BowdenDH, WyattJP. A pathway to pulmonary fibrosis: An ultrastructural study of mouse and rat following radiation to the whole body and hemithorax. Am J Pathol1970;58:481–498.
6.
MaisinJR. The ultrastructure of the lung of mice exposed to a supra-lethal dose of ionizing radiation on the thorax. Radiat Res1970;44:545–564.
7.
PhillipsTL. An ultrastructural study of the development of radiation injury in the lung. Radiology1966;87:49–54.
8.
TravisEL, DownJD, HolmesSJ, HobsonB.Radiation pneumonitis and fibrosis in mouse lung assayed by respiratory frequency and histology. Radiat Res1980;84:133–143.
9.
SiemannDW, HillRP, PenneyDP. Early and late pulmonary toxicity in mice evaluated 180 and 420 days following localized lung irradiation. Radiat Res1982;89:396–407.
10.
BottomleyPA, FosterTH, ArgersingerRE, PfeiferLM. A review of normal tissue hydrogen NMR relaxation times and relaxation mechanisms from 1-100 MHz: Dependence on tissue type, NMR frequency, temperature, species, excision, and age. Med Phys1984;11:425–448.
11.
HayesCE, CaseTA, AilionDC. Lung water quantification by nuclear magnetic resonance imaging. Science1982;216:1313–1315.
12.
CutilloAG, MorrisAH, BlatterDD, . Determination of lung water content and distribution by nuclear magnetic resonance. J Appl Physiol1984;57:583–588.
13.
WexlerHR, NicholsonRL, PratoFS, CareyLS, VinitskiS, ReeseL.Quantitation of lung water by nuclear magnetic resonance imaging: A preliminary study. Invest Radiol1985;20:583–590.
14.
PratoFS, KurdyakR, SaibilEA, RiderWD, AspinN.Regional and total lung function in patients following pulmonary irradiation. Invest Radiol1977;12:224–237.
15.
PratoFS, KurdyakR, SaibilEA, RiderWD, AspinN.Physiological and radiographic assessment during the development of pulmonary fibrosis. Radiology1977;122:389–397.
16.
TeatesCD. The effects of unilateral thoracic irradiation on pulmonary blood flow. Am J Roentgenol1968;102:875–882.
17.
JohnsonPM, SagermanRH, DombrowskiCS. Ischemia of the lung due to ionizing radiation. Quantitative studies. J Nucl Med1970;11:491–495.
18.
KeyeuxA, DunjicA, RoyerE, . Late functional and circulatory changes in rats after local irradiation. Int J Radiat Biol1971;20:7–25.
19.
FreedmanGS, LofgrenSB, KligermanMM. Radiation-induced changes in pulmonary perfusion. Radiology1974;112:435–437.
20.
PratoFS, DrostDJ, KeysT, LaxonP, ComissirongB, SestiniE.Optimization of signal to noise ratio in calculated T1 images derived from two spin-echo images. Mag Res Med1986;3(2):63–75.
21.
LauterburPC. Feasibility of NMR zeumatographic imaging of the heart and lungs. In: PrestonK, TaylorKJW, JohnsonSA, AyersWR, editors. Medical imaging techniques: A comparison. New York: Plenum Press, 1979:209–218.
22.
LallemandDP, BraschRC, GoodingCA, WesbeyGE, HigginsCB. NMR imaging of lung parenchyma. Mag Res Med1984;1:190–191.
23.
GlazerHS, LevittRG, LeeJK, EmamiB, GronemeyerS, MurphyWA. Differentiation of radiation fibrosis from recurrent pulmonary neoplasm by magnetic resonance imaging. AJR1984;143(4):729–730.
24.
GlazerHS, LeeJK, LevittRG, . Radiation fibrosis: Differentiation from recurrent lung by MR imaging. Radiology1985;156:721–726.
25.
HricakH, HigginsCB, WilliamsRD. Nuclear magnetic resonance imaging in retroperitoneal fibrosis. AJR1983;141:35–38.
26.
DoyleFH, PennockJM, BanksLM, . Nuclear magnetic resonance imaging of the liver: Initial experience. AJR1982;138:193–200.
