Ekuskeneni kwe-PW Doppler kwemikhumbi ejikelezayo, ukugeleza kwegazi ngendlela eyodwa okuhle kutholwa ngokucacile, kodwa i-spectrum yesithombe sesibuko esisobala singatholakala ku-spectrogram.Ukunciphisa amandla omsindo odluliselayo kunciphisa kuphela ukugeleza kwegazi okuya phambili nokuhlehlayo ngezinga elifanayo, kodwa akwenzi isipoki sinyamalale.Kuphela uma imvamisa yokukhipha ilungiswa, umehluko ungatholakala.Uma iphezulu imvamisa yokukhipha, kuba sobala kakhulu i-spectrum yesithombe sesibuko.Njengoba kuboniswe emfanekisweni olandelayo, i-spectrum yokugeleza kwegazi emithanjeni ye-carotid iveza i-spectra yesibuko esisobala.Amandla esibuko sesibuko sokugeleza kwegazi okunegethivu anobuthaka kancane kunobubanzi obuphozithivu bokugeleza kwegazi, futhi isivinini sokugeleza siphezulu.Kungani lokhu?
Ngaphambi kokutadisha izipoki, ake sihlole ugongolo lwe-ultrasound scan.Ukuze uthole ukuqondisa okungcono, umsebe wokuskena nge-ultrasonic udinga ukugxila ekulawuleni ukubambezeleka okuhlukile kwezinto eziningi.I-ultrasonic beam ngemva kokugxila ihlukaniswe ibe yi-lobe eyinhloko, i-side lobe kanye nesango lesango.Njengoba kuboniswe ngezansi.
Ama-lobes ayinhloko namaceleni ahlala ekhona, kodwa hhayi ama-gating lobes, okungukuthi, lapho i-angle ye-gating lobe inkulu kunama-degree angu-90, awekho ama-lobes wokungena.Uma i-engeli ye-lobe yokugenca incane, i-amplitude ye-lobe yokugenca ivamise ukuba nkulu kakhulu kunelobe eseceleni, futhi ingase ibe ukuhleleka okufanayo kobukhulu njengelobe eyinhloko.Umthelela oseceleni we-grating lobe kanye ne-side lobe ukuthi isignali yokuphazamiseka echezuka emugqeni wokuskena ibekwe phezulu ku-lobe eyinhloko, okunciphisa ukugqama kwesithombe.Ngakho-ke, ukuze kuthuthukiswe ukugqama kwesithombe, i-amplitude ye-lobe eseceleni kufanele ibe yincane futhi i-engeli ye-gating lobe kufanele ibe nkulu.
Ngokwefomula ye-engeli ye-lobe eyinhloko, imbobo enkulu (W) kanye nemvamisa ephezulu, i-lobe eyinhloko icoleke kakhulu, okuzuzisayo ekuthuthukiseni ukulungiswa kwecala le-imaging yemodi ye-B.Esicathulweni sokuthi inani lamashaneli lihlala njalo, lapho isikhala se-elementi (g) sikhulu, imbobo (W) izoba nkulu.Kodwa-ke, ngokuya ngefomula ye-engeli yokugenca, i-engeli yokugenca nayo izokwehla ngokunyuka kwemvamisa (ukuncipha kwe-wavelength) kanye nokwenyuka kwesikhala sesici (g).Uma i-engeli ye-gating lobe incane, iphakamisa i-lobe ye-gating amplitude.Ikakhulukazi lapho umugqa wokuskena uphambukisiwe, ukuphakama kwe-lobe eyinhloko kuzokwehla lapho indawo ye-lobe eyinhloko ichezuka phakathi nendawo.Ngesikhathi esifanayo, isikhundla se-gating lobe sizoba seduze nendawo, ukuze ukuphakama kwe-gating lobe kuzokwanda nakakhulu, futhi kwenze ama-lobes amaningi wokungena endaweni yokubuka izithombe.
Isikhathi sokuthumela: Feb-07-2022
