| Objective: To investigate the normal appearances of whole body diffusion weighted imaging(WBDWI). To analyze the relationship among the signal intensity(SI) on DWI, STIR and the apparent diffusion coefficient(ADC) values of bone marrow. To identify age and sex-related changes in the apparent diffusion coefficient(ADC) of bone marrow in healthy adult. And assessed the diagnostic value of WBDWI for healthy examination, detecting metastatic tumor, searching for primary tumor when metastasis suspected, suspected systemic multiple disease searching for other lesions.Methods: A total of 98 healthy volunteers(male, 47 years;female, 51 years;mean age, 44.8±13.5 years;range, 21～81 years). All the subjects were divided into nine groups based on ages. Group1: 21～25 years old; group2: 26～30 years old; group3: 31～35 years old; group4: 36～40 years old; group5: 41～45 years old; group6: 46～50 years old; group 7: 51～55 years old; group8: 56～60 years old; group9: >60 years old. All the subjects underwent WBDWI at 1.5-T MR scanner(Siemens, Avanto). The ADC value, SI on DWI and STIR of thoracic vertebra, lumbar vertebra, head of femur, neck of femur, superior segment of femur, inferior segment of femur, ilium, head of humerus, scapula were measured, and the ADC value of liver, spleen, kidney were measured. The normal appearances of WBDWI were assessed. The relationship among the SI on DWI, STIR and the ADC values of bone marrow were analyzed. The ADC values of bilateral symmetrical tissues were compared. The ADC values of bone marrow in different bone were compared. The ADC value of bone marrow and liver, spleen, kidney between male and female were compared and their correlations with age were invesfigated by Spearman's correlation analysis.The ADC value of different region in variable age were compared.82 subjects who underwent WBDWI examination during February 2009 to October 2010 were chosen in the study, 82 subjects include: male, 54;female, 28;mean age, 54.3±12.3;range, 18～82. We assessed the value of WBDWI for detecting lesions.Results:1 Normal appearances of WBDWIThe bone marrow in 69 healthy volunteers showed low to intermediate signal intensity, while which in 29 healthy volunteers showed high signal intensity. Liver in all the healthy volunteers showed low to intermediate signal intensity, spleen and kidney showed high signal intensity.2 Correlation among the signal intensity(SI) on DWI, STIR and the apparent diffusion coefficient(ADC) values of bone marrowThere was significant positive correlation between the ADC values, SI on DWI and STIR of bone marrow in all the bone except the inferior segment of femur. It is to say the higher the ADC values of bone marrow, the higher the SI on DWI, STIR.3 Comparison of the ADC values of bilateral symmetrical tissuesRasults revealed that no significant difference was found in the ADC values between the right side and the lift side of bilateral symmetrical tissues.4 Comparison of the ADC values of bone marrow in different bone There was significant difference of the ADC values of bone marrow in different bone. Student–Newman–Keuls test revealed that no significant difference was found in the ADC values between thoracic vertebra and lumbar vertebra, ilium and scapula, head of humerus and inferior segment of femur, and significant difference was found in the ADC values between the other two groups. The order of the ADC values of bone marrow in different bone from high to low was superior segment of femur, thoracic vertebra and lumbar vertebra, ilium and scapula, neck of femur, head of humerus, head of femur and inferior segment of femur.5 Comparison of the ADC values in different region between the sexes When the ADC values of bone marrow for male subjects and female subjects in different bone were compared, the ADC values of bone marrow were significantly higher in the female subjects in thoracic vertebra, lumbar vertebra, head of femur, neck of femur, superior segment of femur, inferior segment of femur, ilium, head of humerus, scapula. However, the ADC values of liver, spleen, kidney were not significantly different between male subjects and female subjects.6 Correlation between the ADC values of bone marrow and age for male subjects and female subjectsThere was significant negative Correlation between the ADC values of bone marrow and age in thoracic vertebra, lumbar vertebra, head of femur, neck of femur, superior segment of femur, ilium, head of humerus for female subjects. While there was no significant negative Correlation between the ADC values of bone marrow and age in inferior segment of femur and scapula for female subjects and all the regions for male subjects.7 Comparison of the ADC values of bone marrow in different bone in each age groupThere was significant difference of the ADC values of bone marrow in different bone in each age group. The ADC values of bone marrow was highest in 21 to 25 age group, except in inferior segment of femur, in which the ADC values of bone marrow was highest in 46 to 50 age group. 8 serch for lesionOf 82 subjects who underwent WBDWI, including 38 for healthy examination, 23 searching for metastatic tumor, 14 suspected metastatic tumor searching for primary tumor, 5 sespected systemic multiple disease searching for other lesions, 2 found other disease underwent WBDWI.In 82 subjects, we found the lesion include: cranial facial(sinusitis, nasal pharynx tumor, intracranial and skull tumor); neck(thyroid tumor); chest(pulmonitis, tumor, pleural effusion); abdomen(liver and kidney cyst, liver tumor, kidney tumor, stomach tumor, deformity of kidney); pelvic(myoma of uterus); bone(inflammation, degenerative disc disease and schmorl node, infection, benign fracture, tumor, myelosis); joint(effusion); lymphoma; tomor bolt of inferior vena cava; soft tissue tumor. Of 23 patients searching for metastatic tumor, the primary tumor of 13 patients had been resected, and were found in the other 10 patients by WBDWI. The primary tumor of 23 patients include: 4 lung cancer(2 after operation, 2 without operation); 7 liver cancer(3 after operation, 4 without operation); 3 breast cancer after operation; 1 carcinoma of gastric cardia after operation; 1 ampullary carcinoma after operation; 1 carcinoma of colon sigmoideum after operation; 1 cervical cancer after operation; 1 Ewing's sarcoma in retroperitoneal after operation; 3 lymphoma; 1 distal gastric cancer. In 23 patients, we detected 89 lesions except the primary tumor, which shown high signal intensity on STIR and DWI(b=0,800s/mm2). The location of the 89 lesions include: 60 located in bone, 23 located in liver, 3 located in kidney, 1 located in head, 1 located in inferior vena cava, 1 located in abdominal cavity. 45 of 89 lesions were found on CT and MRI images, which confirmed metastatic tumor, other lesions were not did CT or MRI scan. Moreover ,we found 43 lesions which shown high signal intensity on STIR and DWI(b=0s/mm2), significant low signal intensity on DWI(b=800s/mm2). The location of the 43 lesions include: 9 liver cyst; 19 kidney cyst,; 11 sinusitis; 1 pleural effusion; 1 abdominal effusion.14 patients who were suspected metatastic tumor searching for primary tumor, 7 had been found primary tumor, include: 5 lung cancer, 1 liver cancer,1 thyroid carcinoma. 2 patients had not been found primary tumor, considered metatastic tumor with CT,MRI and clinical history. 5 patients were not confirmed metatastic tumor.5 patients who sespected systemic multiple disease was searching for other lesions. 1 patient was found the lesions in the sternum and sternoclavicular joint, which suspected synovitis-acne-pustulosis- hyperostosis -osteomyelitis syndrome(SAPHO), he underwent WBDWI in order to search for other lesions, but no other lesion was found. 1 patient was found the lesions in the humerus and liver, which shown high signal intensity on STIR and DWI(b=0,800s/mm2), the patient was confirmed endogenous cartilage tumor of the humerus and hepatic hemangioma with CT. 1 patient who was diagnosed hemangioma, she underwent WBDWI in order to search for other lesions, the lesion in the nasal pharynx, liver, kidney, vertebra and soft tissue in the lateral of the left ilium were found. All the bone marrow of 1 patient with polycythemia vera and 1 patient with autoimmune hemolytic anemia shown high signal intensity on STIR and DWI(b=800s/mm2).2 patients were found other disease who underwent WBDWI. The lesion in the lung was found on STIR in 1 patient with pulmonary embolism, but not found in DWI, which consided lung inflammation. 1 patient was found the lesion in the right cerebellopontine angle, which shown hetergenous high signal intensity on STIR and DWI(b=0s/mm2), significant low signal intensity on DWI(b=800s/mm2).Conclusion: 1 Bone marrow on DWI was shown high signal intensity and low to intermediate signal intensity. The fraction of bone marrow which shown high signal on DWI for female as follow: for female who were 21～25 years old was 89%(8/9); for female who were 26～30 years old was 100%(2/2); for female who were 31～35 years old was 100%(4/4); for female who were 41～45 years old was 100%(5/5). The fraction of bone marrow which shown high signal on DWI for female who were 21～35 , 41～45 years old was significantly high, it is probablely normal appearance when see high signal of bone marrow on DWI in these ages.2 The fraction of bone marrow which shown high signal on DWI for female who were 36～40 years old was 25%(1/4); for female who were 46～50 years old was 36%(5/14); for female who were 51～55 years old was 20%(1/5); for female who were 56～60 years old was 0%(0/3); for female who were>60 years old was 20%(1/5). For male who were 31～35 years old was 25%(1/4); for male who were>60 years old was 33%(1/3). We should identified carefully when see high signal of all bone marrow on DWI in these ages, not diagnosed as blood diseases and metatastic tumor. 3 Blood diseases and metatastic tumor also shown high signal intensity on DW(Ib=800s/mm2). It was dependent on STIR images to distinguish the high signal intensity among blood diseases, metatastic tumor and normal bone marrow. The high signal intensity of blood diseases was higher than that of the normal bone marrow, and both of them were homogenous. While metatastic tumor shown hetergenous high signal intensity. Some lesions were found on STIR, but not found on DWI, so STIR images is important to diagnose disease.4 The higher the ADC values of bone marrow, the higher the SI on DWI, STIR.5 The ADC value of bone marrow was affected by age, it was highest in 21～25 years old in all bone that we measured except the inferior segment of right femur, in which the ADC value was highest in 46～50 years old. There was negative correlation between the ADC value of bone marrow in either bone for female and age, that is to say the older the age, the lower the ADC value. There was no correlation between the ADC value of bone marrow in either bone for male and age.6 The ADC value of bone marrow was affected by sex. The ADC value of bone marrow for female was higher than that for male in each region.7 The ADC value of bone marrow was different in different bone. The order of the ADC values of bone marrow in different bone from high to low was superior segment of femur, thoracic vertebra and lumbar vertebra, ilium and scapula, neck of femur, head of humerus, head of femur and inferior segment of femur.8 WBDWI could display various lesion in multiple region, it is valuable imaging method, WBDWI have important clinical value for health examination, detection of metastatic tumor, sespected metastatic tumor searching for primary tumor, sespected systemic multiple disease searching for other lesions. |
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