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VLOGA SODOBNIH MAGNETNORESONANČNIH SLIKOVNIH TEHNIK IN PRIPRAVE PACIENTA PRI OPREDELITVI RAKA PROSTATE
Caglič, Iztok (Avtor), Kovač, Viljem (Mentor) Več o mentorju... Povezava se odpre v novem oknu, Barrett, Tristan (Komentor)

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Izvleček
Ozadje Slikanje z magnetno resonanco (MR) se je uveljavilo kot standardna diagnostična metoda pri odkrivanju in oceni lokalne razširjenosti raka prostate (RP), pri čemer je osnovni predpogoj dobra kvaliteta slik. Le-to bi lahko nadgradili z vključitvijo tridimenzionalnega T2-obteženega slikanja (3 dimensional T2-weighted imaging, 3D-T2WI) v standardni protokol, saj omogoča rekonstrukcijo slik v poljubni ravnini, s čimer bi lahko bolje prikazali stik tumorja z ovojnico prostate. Neodvisno od tehnike slikanja vplivajo na kvaliteto slik še različni dejavniki pri bolnikih kot sta črevesna peristaltika in prekomerna razširjenost danke. Smernice PI-RADS (Prostate Imaging-Reporting and Data System) poudarjajo pomanjkanje dokazov na obeh področjih in zato ne vsebujejo navodil glede priprave pacienta pred MR slikanjem. Namen Naš namen je bil primerjati 3D-T2WI z običajnim dvodimenzionalnim T2-obteženim slikanjem (2D-T2WI) pri opredelitvi lokalne razširjenosti RP. Želeli smo tudi raziskati vpliva antispazmolitika hioscin butilbromida (HBB) in razširjenosti danke na kvaliteto anatomskega in funkcijskega MR slikanja prostate. Preiskovanci in metode Vse študije smo opravili na 3 Tesla (3T) MR-tomografu v skladu s PI-RADS protokolom, ki je vključeval T2-obteženo slikanje (T2-weighted imaging, T2WI), T1-obteženo slikanje (T1-weighted imaging, T1WI), difuzijsko obteženo slikanje (Diffusion weighted imaging, DWI) z maksimalno b-vrednostjo 2000s/mm2, navidezni difuzijski koeficient (Apparent diffusion coefficient, ADC) in dinamično kontrastno ojačano slikanje (Dynamic contrast enhanced imaging, DCEI). V prvo študijo je bilo vključenih 75 preiskovancev po radikalni prostatektomiji, ki so pred tem opravili MR slikanje prostate. Najprej smo na 2D-T2W slikah lezije z vrednostmi PI-RADS ≥ 4 na 5-stopenjski lestvici Likert (1 = ne prerašča, 5 = prerašča) subjektivno ocenili ali preraščajo ovojnico (extracapsular extension, ECE) ter izmerili dolžino kontakta med tumorjem in ovojnico. Nato smo branje ponovili z uporabo 3D-T2WI, kjer smo dodatno rekonstruirali potrebne ravnine, da smo določili maksimalni 3D kontakt in 3D površino. V drugo študijo II je bilo vključenih 87 bolnikov, ki so pred MR slikanjem prejeli 20 mg hioscinijevega butilbromida (HBB skupina) in 86 bolnikov v kontrolni skupini, ki HBB niso prejeli. Dva radiologa sta ovrednotila kvaliteto T2W, DWI in ADC slik s 5-stopenjsko Likert-ovo lestvico. DWI smo dodatno ocenili glede na stopnjo distorzije in artefaktov in T2W na prisotnost artefaktov zaradi premikanja in zmanjšane ostrine slike. Kvaliteto DCEI smo ovrednotili glede na število popačenih vrednosti na kontrastni krivulji. V tretji študiji sta MR slike 173 preiskovancev ovrednotila dva radiologa. Volumen danke je bil izračunan s planimetrijo in subjektivna ocena razširjenosti danke je bila podana s 5-stopenjsko lestvico Likert (1 = brez blata/zraka, 5 = velika količina blata/zraka). Na DWI so bili ocenjeni kvaliteta in stopnja distorzije slike ter arefakti. Na T2W slikah smo ocenjevali prisotnost artefaktov zaradi premikanja in ostrino slike. Kvaliteto DCEI smo ocenjevali enako kot pri drugi študiji. Rezultati Pri prvi študiji smo ECE ocenjevali pri 106 lezijah. ECE je bil prisotna pri 54% vseh lezij z oceno PI-RADS  4 in pri 64% bolnikov. ECE je bila histološko potrjena kot fokalna v 28% in kot makroskopska v 72%. Senzitivnost subjektivne ocene ECE s 3D-T2W slikami je bila neznačilno višja kot s 2D-T2W slikami (75.4% proti 64.9%, p = 0.06), specifičnost je bila neznačilno nižja (83.7% proti 85.7%, p = 0.71). Ocena določena z lestvico Likert na 3D-T2W slikah je bila pri lezijah z ECE značilno višja (3.7 ± 1.4 versus 3.3 ± 1.4, p < 0.01), pri lezijah brez ECE pa neznačilno nižja (1.5 ± 1 proti 1.6 ± 0.9, p=0.27) kot pri 2D-T2W slikah. 3D kontakt je imel značilno višjo senzitivnost (73.7%) kot 2D kontakt (59.6%, p = 0.03), pri čemer je bila specifičnost enaka 87.8% (p = 1). 3D površina je značilno zvišala senzitivnost z 59.6% na 82.5% (p < 0.01, kar je bilo povezano z neznačilno znižano specifičnostjo z 87.8% na 71.4% (p < 0.01). Tumorji z visokim gradusom (High grade group, HGG) so imeli značilno višjo prevalenco ECE kot tumorji nizkega gradusa (low grade group, LGG): 88% proti 44%, p < 0.01. 90.9% pozitivna napovedna vrednost (PNV) HGG tumorjev je bila dosežena pri dolžini kontakta ≥ 5 mm, pri LGG tumorjih je bila 90.4% PNV pri dolžini kontakta ≥ 12.5 mm. Druga študija II je pokazala značilno višjo kvaliteto T2W slik v HBB skupini kot v kontrolni skupini (3.6 ± 1.1 versus 2.8 ± 0.9); p = <0.01. V HBB skupini je bilo značilno manj artefaktov zaradi premikanja in zmanjšane ostrine T2W slik (23.0% proti 53.5% in 51.7% proti 83.7%, p = <0.01). Značilno izboljšane kvalitete DWI in ADC slik ali zmanjšane DWI distorzije in artefaktov v HBB skupini ni bilo. Ocena DCEI je pokazala neznačilen trend z zmanjšanim številom popačenih vrednosti na krivulji (2.5 ± 2.4 versus 3.7 ± 2.6), p = 0.05. Tretja študija je pokazala značilno negativno povezavo med razširjenostjo danke in kvaliteto DWI (r = -0.628, p < 0.01) ter značilno pozitivno povezavo z distorzijo DWI (r = 0.814, p < 0.01). Med razširjenostjo danke in prisotnostjo artefaktov na DWI (r = 0.15, p = 0.04) ter povečanjem artefaktov T2W slikah (p < 0.01) je bil značilen pozitiven trend. Med stopnjo razširjenosti danke in ostrino T2W slik ter kvaliteto DCEI ni bilo povezave. 63 bolnikov je po slikanju z MR imelo usmerjeno tarčno biopsijo prostate, kjer je bil opazen trend z višjo PPV pri bolnikih z nizko stopnjo razširjenosti danke v primerjavi z bolniki z zmerno/visoko stopnjo razširjenosti. Zaključki Uporaba 3D-T2W slikanja je v primerjavi s standardnim 2D-T2W slikanjem značilno zvišala senzitivnost in zaupanje radiologa pri diagnosticiranju ECE. Prag dolžine kontakta z ovojnico je bil značilno daljši pri LGG kot pri HGG tumjih. Povečana razširjenost danke je imela značilen negativni vpliv na kvaliteto T2W in DWI slikanja, medtem ko je HBB signifikantno izboljšal kvaliteto T2W slik. Glede na te rezultate svetujemo uporabo 3D-T2WI za boljšo odkrivanje ECE kot tudi pripravo črevesja in rutinsko uporabo HBB pred MR slikanjem prostate, da bi izboljšali kvaliteto slik.

Jezik:Slovenski jezik
Ključne besede:multiparametrična magnetna resonanca, rak prostate, tridimenzionalno slikanje, določanje stadija raka, kvaliteta slik, artefakti, razširjenost danke, hioscinijev butilbromid
Vrsta gradiva:Doktorsko delo/naloga (mb31)
Organizacija:MF - Medicinska fakulteta
Leto izida:2019
Število ogledov:593
Število prenosov:132
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:THE ROLE OF MODERN MAGNETIC RESONANCE IMAGING TECHNIQUES AND PATIENT PREPARATION IN EVALUATION OF PROSTATE CANCER
Izvleček:
Background Magnetic resonance imaging (MRI) is a standard diagnostic procedure for evaluation of prostate cancer (PCa) and good image quality is essential. This could potentially be improved by adding three-dimensional T2 weighted imaging (3D-T2WI) to the standard protocol as it enables reconstruction of images in any given plane, potentially allowing us to better demonstrate the tumour/capsular interface. Independent of scanner parameters, patient factors such as bowel peristalsis and rectal distension by gas/stool can also affect image quality. The Prostate Imaging-Reporting and Data System (PI-RADS) guidelines acknowledge that there is currently lack of evidence in both areas and therefore no direct recommendation on patient preparation is given. Purpose To compare 3D-T2WI with conventional 2D-T2WI in assessment of local staging of PCa. We also examined the effect of anti-peristaltic agent hyoscine butylbromide (HBB) and rectal distension on the quality of anatomical and functional MR imaging of prostate. Patients and methods All studies were performed at 3T MRI scanner using PI-RADS recommended protocol including T2 weighted imaging (T2W), T1 weighted imaging (T1WI), diffusion weighted imaging (DWI) with maximum b-value at 2000s/mm2, apparent diffusion coefficient (ADC) maps and dynamic contrast enhanced (DCE) images. The first study included 75 patients undergoing MRI before radical prostatectomy. PI-RADS ≥4 lesions were assessed for extracapsular extension (ECE) on 2D-T2W images using a 5-point Likert scale and the length of tumour prostatic capsular contact. A second read using additional 3D-T2W images and reformats evaluated ECE and the maximal 3D capsular contact length and surface. The second study included 87 patients receiving 20 mg HBB prior to scanning (HBB group) and 86 patients who did not (non-HBB group). Two radiologists evaluated image quality of T2WI, DWI and ADC maps, using a 5-point Likert scale. DWI was further assessed for distortion and artefact, and T2WI for the presence of motion artefact or blurring. DCE image quality was assessed by recording the number of corrupt data points from the curve. In the third study, images of 173 patients were evaluated by two radiologists. Rectal volumes were calculated and a subjective assessment of rectal distension was made using a 5-point Likert scale (1 = no stool/gas, 5 = large amount of stool/gas). DWI was scored for image quality, distortion and artefact. T2W images were evaluated for image sharpness and the presence of motion artefact. The stability of the DCE was assessed as in the second study. Results In the first study a total of 106 lesions were analysed for the presence of ECE. ECE was present in 54% of lesions with PI-RADS score of ≥ 4 and in 64% of all patients. ECE was reported as focal in 28% and established in 72%. In terms of subjective reads, sensitivity and specificity for 3D-T2 was 75.4% versus 64.9% for conventional 2D-T2 (p = 0.06), respectively and 83.7% versus 85.7% (p = 0.71) for conventional 2D-T2, respectively. 3D-T2 reads showed a significantly higher mean Likert score of 3.7 ± 1.4 versus 3.3 ± 1.4 (p < 0.01) in ECE positive lesions and non-significantly lower Likert score for ECE negative lesions with average score of 1.5 ± 1 versus 1.6 ± 0.9 (p = 0.27) as compared to 2D-T2. 3D-contact assessment had significantly higher sensitivity (73.7%) than 2D-contact (59.6%, p = 0.03), whilst maintaining the same specificity of 87.8% (p = 1). 3D-surface area evaluation increased sensitivity from 59.6% to 82.5% (p < 0.01) but this was associated with a loss of specificity from 87.8% to 71.4% (p < 0.01). High grade group (HGG) tumours showed significantly higher ECE prevalence (88%) than low grade group (LGG) at 44%, p < 0.01. In addition, in HGG a PPV of 90.9% was achieved at ≥ 5 mm, conversely for LGG, a PPV of 90.4% was achieved at a cut-off at ≥ 12.5 mm. The second study showed significantly higher T2W image quality in the HBB group than in the non-HBB group (3.6 ± 1.1 versus 2.8 ± 0.9); p = < 0.01. The HBB group also showed significantly less T2W motion and T2W blur than the non-HBB group (23.0% and 51.7% versus 53.5% and 83.7%, respectively; p = < 0.01). However, there was no significant improvement in DWI or ADC image quality, or DWI degree of distortion or artefact. There was a trend towards a lower number of corrupted data points from the contrast curve (2.5 ± 2.4 versus 3.7 ± 2.6), p = 0.05. The third study showed a significant correlation between increased rectal distension and both reduced DW image quality (r = -0.628, p < 0.01), and increased DW image distortion (r=0.814, p < 0.01). There was a significant trend for rectal distension to increase artefact at DWI (r = 0.154, p = 0.04) and to increase motion artefact on T2 (p < 0.01). There was no relationship between rectal distension and T2-sharpness or DCE image quality. 63 patients underwent lesion-targeted biopsy post MRI, there was a trend to higher positive predictive values in patients with minor rectal distension compared to those with moderate/marked distension. Conclusions The use of 3D-T2 showed significantly increased sensitivity and confidence in calling ECE over conventional 2D-T2. In addition, capsular contact length threshold was significantly longer for LGG than HGG lesions. Rectal distension had a significant negative effect on the quality of both T2W and DW images whereas the administration of HBB was significantly associated with improved image quality of T2W images. Consideration should therefore be given to 3D-T2W imaging for improved detection of ECE as well as to bowel preparation and the routine use of HBB to optimise image quality of mpMRI of prostate.

Ključne besede:multiparametric MRI, prostate cancer, three dimensional imaging: tumour staging, image quality, artefacts, rectal distension, hyoscine butylbromide

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