Multi-Detector row CT urography on a 16-row CT scanner in the ...
Multi-Detector row CT urography on a 16-row CT scanner in the ...
Multi-Detector row CT urography on a 16-row CT scanner in the ...
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With <strong>the</strong> <strong>in</strong>troducti<strong>on</strong> of <strong>16</strong>-<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <strong>scanner</strong>s, <strong>the</strong><br />
radiologic evaluati<strong>on</strong> of <strong>the</strong> ur<strong>in</strong>ary tract is chang<strong>in</strong>g<br />
rapidly. The advantages of a <strong>16</strong>-<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <strong>scanner</strong> are <strong>the</strong><br />
follow<strong>in</strong>g: fast scann<strong>in</strong>g (coverage of at least 48 mm l<strong>on</strong>g<br />
body secti<strong>on</strong>s per sec<strong>on</strong>d), acquisiti<strong>on</strong> of th<strong>in</strong> collimati<strong>on</strong><br />
and creati<strong>on</strong> of high-resoluti<strong>on</strong> multiplanar and threedimensi<strong>on</strong>al<br />
(3D) reformatted images, with excellent<br />
anatomic details [<strong>16</strong>, 17]. The purpose of our study was<br />
to assess <strong>the</strong> role of multi-detector <str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <str<strong>on</strong>g>urography</str<strong>on</strong>g>,<br />
us<strong>in</strong>g a <strong>16</strong>-<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <strong>scanner</strong> <strong>in</strong> <strong>the</strong> evaluati<strong>on</strong> of patients<br />
present<strong>in</strong>g with pa<strong>in</strong>less hematuria, with emphasis placed<br />
<strong>in</strong> <strong>the</strong> detecti<strong>on</strong> of uro<strong>the</strong>lial tumors.<br />
Materials and methods<br />
This study was a retrospective review of <str<strong>on</strong>g>CT</str<strong>on</strong>g> urographies<br />
performed <strong>on</strong> a <strong>16</strong>-<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <strong>scanner</strong> for <strong>the</strong> evaluati<strong>on</strong> of<br />
pa<strong>in</strong>less hematuria. The study <strong>in</strong>cluded 75 c<strong>on</strong>secutive<br />
patients (47 men and 28 women) with a mean age of 63<br />
years (age range: 21–87 years), who underwent multidetector<br />
<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <str<strong>on</strong>g>urography</str<strong>on</strong>g> between March 2004 and<br />
January 2005, referred to <strong>the</strong> department of Radiology for<br />
pa<strong>in</strong>less hematuria. Five patients were younger than 40<br />
years old. Informed c<strong>on</strong>sent for this study was obta<strong>in</strong>ed<br />
from each patient.<br />
The cl<strong>in</strong>ical evaluati<strong>on</strong> of <strong>the</strong> patients <strong>in</strong>cluded a careful<br />
history and cl<strong>in</strong>ical exam<strong>in</strong>ati<strong>on</strong>. The laboratory analysis<br />
began with a comprehensive exam<strong>in</strong>ati<strong>on</strong> of <strong>the</strong> ur<strong>in</strong>e and<br />
ur<strong>in</strong>e sediment and cytologic analysis. All patients had an<br />
ultrasound exam<strong>in</strong>ati<strong>on</strong> of <strong>the</strong> abdomen, some performed<br />
at an outpatient cl<strong>in</strong>ic and <strong>the</strong> rest at our department.<br />
Patients with hematuria and a s<strong>on</strong>ographic exam<strong>in</strong>ati<strong>on</strong><br />
dem<strong>on</strong>strat<strong>in</strong>g a kidney mass were not <strong>in</strong>cluded <strong>in</strong> this<br />
study, s<strong>in</strong>ce <strong>the</strong>y were evaluated with a different protocol<br />
tailored for <strong>the</strong> <strong>in</strong>vestigati<strong>on</strong> of renal masses. Cystoscopic<br />
exam<strong>in</strong>ati<strong>on</strong> was carried out <strong>in</strong> all patients.<br />
In patients <strong>in</strong> whom cl<strong>in</strong>ical and imag<strong>in</strong>g evaluati<strong>on</strong><br />
revealed no cause for <strong>the</strong> hematuria, a follow-up was<br />
recommended. This <strong>in</strong>cluded <strong>the</strong> repeat of <strong>the</strong> ur<strong>in</strong>ary<br />
analysis and ur<strong>in</strong>e cytology every m<strong>on</strong>th for <strong>the</strong> first 4<br />
m<strong>on</strong>ths and <strong>the</strong>reafter at 6, 12, 24 and 36 m<strong>on</strong>ths.<br />
Immediate reevaluati<strong>on</strong> with repeat of <strong>the</strong> <str<strong>on</strong>g>CT</str<strong>on</strong>g> exam<strong>in</strong>ati<strong>on</strong><br />
and/or cystoscopy and ur<strong>in</strong>e cytology was recommended if<br />
any of <strong>the</strong> follow<strong>in</strong>g occurred: development of gross<br />
hematuria, abnormal ur<strong>in</strong>ary cytologic f<strong>in</strong>d<strong>in</strong>gs or irritat<strong>in</strong>g<br />
void<strong>in</strong>g symptoms <strong>in</strong> <strong>the</strong> absence of <strong>in</strong>fecti<strong>on</strong> [18].<br />
Technique<br />
Exam<strong>in</strong>ati<strong>on</strong>s were performed <strong>on</strong> a <strong>16</strong>-<str<strong>on</strong>g>row</str<strong>on</strong>g> <str<strong>on</strong>g>CT</str<strong>on</strong>g> <strong>scanner</strong><br />
with 24 mm scann<strong>in</strong>g span per rotati<strong>on</strong> (Mx8000 IDT,<br />
Philips) and a three-phase protocol was used. Unenhanced<br />
images were obta<strong>in</strong>ed from <strong>the</strong> kidneys through <strong>the</strong> ur<strong>in</strong>ary<br />
bladder us<strong>in</strong>g a slice collimati<strong>on</strong> of <strong>16</strong>×1.5 mm and a slice<br />
thickness of 3 mm. These images were scrut<strong>in</strong>ized to<br />
identify ur<strong>in</strong>ary tract calculi or calcificati<strong>on</strong>s, as well as to<br />
assist <strong>in</strong> <strong>the</strong> characterizati<strong>on</strong> of any detected renal masses.<br />
Intravenous n<strong>on</strong>-i<strong>on</strong>ic iod<strong>in</strong>ated c<strong>on</strong>trast material (120 ml,<br />
320 mg I/ml) was subsequently adm<strong>in</strong>istered at a rate of<br />
3 ml/sec, via mechanical <strong>in</strong>jector, followed by 250 ml of<br />
normal sal<strong>in</strong>e 0.9%, rapidly <strong>in</strong>fused by <strong>in</strong>travenous drip.<br />
The sec<strong>on</strong>d phase was <strong>the</strong> nephrographic phase obta<strong>in</strong>ed at<br />
100 sec delay, cover<strong>in</strong>g <strong>the</strong> area from <strong>the</strong> diaphragm to <strong>the</strong><br />
iliac crests and <strong>the</strong> third phase was <strong>the</strong> excretory phase<br />
start<strong>in</strong>g with 10-m<strong>in</strong>ute delay, cover<strong>in</strong>g <strong>the</strong> kidneys, ureters<br />
and <strong>the</strong> ur<strong>in</strong>ary bladder. The nephrographic phase was<br />
chosen for <strong>the</strong> detecti<strong>on</strong> and characterizati<strong>on</strong> of renal<br />
masses, as well as for stag<strong>in</strong>g, while <strong>the</strong> excretory phase<br />
was utilized for <strong>the</strong> evaluati<strong>on</strong> of abnormalities <strong>in</strong>volv<strong>in</strong>g<br />
<strong>the</strong> uro<strong>the</strong>lium. For <strong>the</strong>se two phases a secti<strong>on</strong> collimati<strong>on</strong><br />
of <strong>16</strong>×0.75 mm and a slice thickness of 1 mm were<br />
employed. The nephrographic and excretory phase images<br />
were rec<strong>on</strong>structed at 0.5 mm <strong>in</strong>tervals (50% overlap). All<br />
<strong>the</strong> scans were performed with a pitch of 1.2, at 120 kV,<br />
us<strong>in</strong>g a rotati<strong>on</strong> time of 0.5 sec. Both dose modulati<strong>on</strong><br />
(DOM) and automatic current sett<strong>in</strong>g (DoseRight) were<br />
used [19]. No oral c<strong>on</strong>trast material was given, <strong>in</strong> order to<br />
facilitate 3D reformatt<strong>in</strong>g. The entire <str<strong>on</strong>g>CT</str<strong>on</strong>g> <str<strong>on</strong>g>urography</str<strong>on</strong>g><br />
exam<strong>in</strong>ati<strong>on</strong> lasted 15 m<strong>in</strong>utes per patient <strong>on</strong> <strong>the</strong> average<br />
and every scan lasted 7–12 sec<strong>on</strong>ds <strong>on</strong> <strong>the</strong> average. Our <str<strong>on</strong>g>CT</str<strong>on</strong>g><br />
protocol is illustrated <strong>on</strong> Table 1.<br />
<str<strong>on</strong>g>CT</str<strong>on</strong>g> data <strong>in</strong>terpretati<strong>on</strong><br />
Image <strong>in</strong>terpretati<strong>on</strong> was d<strong>on</strong>e <strong>on</strong> a workstati<strong>on</strong> (MxView,<br />
Philips) and <strong>in</strong>cluded <strong>the</strong> study of <strong>the</strong> axial images of <strong>the</strong><br />
unenhanced scan. The evaluati<strong>on</strong> of <strong>the</strong> axial source<br />
images of <strong>the</strong> nephrographic and <strong>the</strong> excretory phase was<br />
Table 1 <str<strong>on</strong>g>CT</str<strong>on</strong>g> protocol for <strong>the</strong> <strong>in</strong>vestigati<strong>on</strong> of hematuria<br />
Unenhanced<br />
scan<br />
Nephrographic<br />
phase,<br />
100 sec<br />
Excretory<br />
phase,<br />
10 m<strong>in</strong><br />
kV, rotati<strong>on</strong> time (sec) 120/0.5 120/0.5 120/0.5<br />
mAsnom/mAssel 200/170 200/175 200/<strong>16</strong>0<br />
<str<strong>on</strong>g>Detector</str<strong>on</strong>g> collimati<strong>on</strong> <strong>16</strong>×1.5 <strong>16</strong>×0.75 <strong>16</strong>×0.75<br />
(mm)<br />
Pitch 1.2 1.2 1.2<br />
Slice thickness (mm) 3 1 1<br />
Rec<strong>on</strong>structi<strong>on</strong> 3 0.5 0.5<br />
<strong>in</strong>terval (mm)<br />
Area<br />
Kidneysur<strong>in</strong>ary<br />
bladder<br />
Diaphragmiliac<br />
crests<br />
Kidneysur<strong>in</strong>ary<br />
bladder<br />
C<strong>on</strong>trast material<br />
(iv)<br />
120 ml (320), 3 ml/sec and 250 ml<br />
sal<strong>in</strong>e 0.9%