ABSTRACT
Objective To investigate the clinical feasibility of contrast?enhanced three dimensional T2WI turbo?spin?echo sequence with short?term inversion recovery and sampling perfection using different flip angle evolutions (3D STIR T2WI SPACE) sequence in the brachial plexus neurography. Methods Thirty two patients were prospectively chosen and performed with brachial plexus plain scanning on a 3.0 T MR scanner by using plain and contrast?enhanced 3D STIR T2WI SPACE sequence. Thirteen of them underwent plain scan, 9 of them underwent contrast?enhanced scan, and 10 of them underwent both plain scan and enhanced scan. The visibility of the brachial plexus were scored and contrast to noise ratio (CNR) were measured by two experienced radiologists. The results between plain and contrast?enhanced imaging were compared by t test. The 10 subjects received both enhance and plain imaging, were performed with paired t test. Results In 32 patients, the visibility score of brachial plexus nerve and CNR were 7.8 ± 1.3 and 24.97±3.41 in the plain scan group, and 13.1±1.7 and 38.49±4.95 in enhanced scan group, respectively. There were statistically significant differences in the two groups(t=-11.72,P<0.01;t=-10.47, P<0.01). In 10 cases with plain and enhanced brachial plexus imaging, the average score of the brachial plexus were 7.4 ± 1.7 and 13.3 ± 1.6, the average CNR were 26.23 ± 4.43 and 38.19 ± 5.03 respectively. There were statistically significant differences (t=- 8.22, P<0.01; t=- 5.64,P<0.01). The score results were analyzed for consistency. Plain images Kappa value was 0.684, which shows moderate consistency and enhanced images Kappa value= 0.822, which shows excelent consistency. Conclusions The contrast?enhanced 3D STIR T2WI SPACE sequences may suppress background tissue signals, which is helpful to display brachial plexus, therefore it is of important value for the early diagnosis of brachial plexus neuropathy.
ABSTRACT
Objective To investigate the effects of exercise on knee cartilage tissue structure using quantitative MR T2 mapping. Methods Sagittal T2 maps of the knee joints of 26 healthy volunteers were obtained by using 3.0T MR before,immediately after, and 1 5 min after running.The original images were classified into three terms of knee cartilage T2 map after postreconstruction.The T2 values of regions of interest (ROC)(T2 pre ,T2 post ,T2 delay )in the superficial,middle and deep cartilage of femoral and tibial joint were measured.Statistical differences of cartilage T2 values of three terms after running were analyzed.Results For the tibial joint cartilage,the T2 pre ,T2 post ,T2 delay were (49.71 ± 1.95)ms,(44.30 ± 2.56)ms,(49.41 ± 1.62)ms in the superficial layer,respectively.The three terms T2 were (42.43 ± 2.23)ms,(39.01 ± 2.37)ms,(41.90±2.28)ms in the middle layer,respectively.The differences were statistically significant(F=55.673,16.759 respectively.P<0.001).While the three terms T2 were (19.39±2.13)ms,(19.20±2.22)ms, (19.49±2.05)ms in the deep layers cartilage,respectively.The differences were not statistically significant(F =0.122,P =0.886).And the differences between T2 pre and T2 post ,T2 post and T2 delay were statistically significant (all P <0.001)in superficial and middle alyers,but there were no significant difference between the T2 pre and T2 delay (P =0.610,0.403,respectively).For the femoral joint cartilage,the T2 pre ,T2 post ,T2 delay were (50.22 ± 1.47)ms,(45.60 ± 2.82)ms,(49.84 ± 1.84)ms in superficial layers,respectively.The three terms T2 were (42.67±2.23)ms,(39.36 ± 1.98)ms,(42.40 ± 2.57)ms in the middle layer,respectively.The differences were statistically significant (F=37.976,16.987 respectively,P<0.001).While the three terms T2 were (20.30±2.73)ms,(20.60±2.44)ms,(20.51± 2.24)ms in the deep layer,the differences were not statistically significant (F =0.098,P =0.907).And the differences between T2 pre and T2 post ,T2 post and T2 delay were statistically significant (all P <0.001)in superficial and middle layers,but there were no significant difference between the T2 pre and T2 delay (P=0.520,0.679,respectively). Spatial distribution of T2 values of articular cartilage from deep to superficial layers showed a ascending trend.T2 maps showed the spatial distribution trend of T2 value change.Conclusion T2 mapping can monitor quantitatively the changes of articular cartilage molecular structure after running.The change of articular cartilage T2 value after exercise is uneven and the change of articular cartilage structure after exercise is reversible.
ABSTRACT
Objective To investigate the site,MR signal types and morphological characteristics of ulnar nerve in cubital tunnel for healthy adults,in order to improve the awareness of ulnar nerve.Methods Unilateral elbow of forty healthy volunteers were scanned with MR,the sequences were as follows:T1-weighted-spin-echo,T2-weighted-spin-echo-fat-suppression,PD-weighted-spin-echo-fat-suppression,among 40,13 were supine,27 were prone.The site and MR signal types and morphological characteristics of ulnar nerve were observed,the long diameter and short diameter of the ulnar nerve on different axials were respectively measured.Results On axial,ulnar nerve was posterior to the medial condyle of the humerus at proximal elbow,lied between the flexor carpi ulnaris and the flexor digitorum profunds and superficialis muscles distally.The shape of the ulnar nerve was roundness or elliptic,the signal of 40 volunteers'(100％) ulnar nerve was isointensity on T1-weighted,the signal of 17 volunteers'(42.5％)ulnar nerve was isointense on T2-weighted or PD-weighted,the MRI signal of 23 volunteers' (57.5％) ulnar nerve was slight hyperintense on T2-weighted or PD-weighted,especially on the axial of medial condyle of humerus.The variation range of long diameter and short diameter of the ulnar nerve respectively were 1.4-3.8 mm,1.0-3.0 mm.Conclusion The certain location,MR signal types and morphological characteristics of normal ulnar nerve play an important role in the diagnosis of cubital tunnel syndrome.