HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Rydberg, J. Articles by Kopecky, K. K. Search for Related Content PubMed PubMed Citation Articles by Rydberg, J. Articles by Kopecky, K. K. Related Collections Computed Tomography Physics and Basic Science

Multisection CT: Scanning Techniques and Clinical Applications¹

¹ From the Department of Radiology, Indiana University School of Medicine, Indianapolis. Recipient of a Certificate of Merit award for a scientific exhibit at the 1999 RSNA scientific assembly. Received March 1, 2000; revision requested April 11; final revision received June 22; accepted July 6. Address correspondence to K.K.K., Department of Radiology, Indiana University Hospital, Rm 0615, 550 N University Blvd, Indianapolis, IN 46202-5253 (e-mail: kkopecky@iupui.edu).

View larger version (24K): [in a new window]   Figure 1a.   Oblique view of a CT gantry with an x-ray tube, an x-ray fan, and detectors for a single-section scanner (a) and a multisection scanner (b) (four-section system shown).

View larger version (50K): [in a new window]   Figure 1b.   Oblique view of a CT gantry with an x-ray tube, an x-ray fan, and detectors for a single-section scanner (a) and a multisection scanner (b) (four-section system shown).

View larger version (28K): [in a new window]   Figure 2.   Equal-width (top diagram) and unequal-width (bottom diagram) detector array designs. Numbers represent individual detector widths in millimeters. The z-axis length of the two designs is identical (20 mm). The equal-width design uses 16 elements; the unequal-width design uses eight elements.

View larger version (30K): [in a new window]   Figure 3a.   Cross-sectional profile of an equal-width detector design. (a) To acquire four 5-mm-thick sections, all 16 detectors are activated. The signals from adjacent groups of four detectors are combined into one channel, creating a virtual detector with a section thickness of 5 mm. (b) To acquire four 1.25-mm-thick sections, only the central four detectors are activated.

View larger version (23K): [in a new window]   Figure 3b.   Cross-sectional profile of an equal-width detector design. (a) To acquire four 5-mm-thick sections, all 16 detectors are activated. The signals from adjacent groups of four detectors are combined into one channel, creating a virtual detector with a section thickness of 5 mm. (b) To acquire four 1.25-mm-thick sections, only the central four detectors are activated.

View larger version (25K): [in a new window]   Figure 4a.   Cross-sectional profile of an unequal-width detector design. (a) To acquire four 5-mm-thick sections, all eight detectors are activated. The signals from the detectors are combined into four channels, each representing a 5-mm-thick virtual detector. (b) To acquire four 2.5-mm-thick sections, the inner six detectors are activated. (c) To acquire four 1-mm-thick sections, pre- and postpatient collimators cover the outer one-third of the 1.5-mm-wide detectors. (d) Two 0.5-mm-thick sections can be created with narrower collimation.

View larger version (21K): [in a new window]   Figure 4b.   Cross-sectional profile of an unequal-width detector design. (a) To acquire four 5-mm-thick sections, all eight detectors are activated. The signals from the detectors are combined into four channels, each representing a 5-mm-thick virtual detector. (b) To acquire four 2.5-mm-thick sections, the inner six detectors are activated. (c) To acquire four 1-mm-thick sections, pre- and postpatient collimators cover the outer one-third of the 1.5-mm-wide detectors. (d) Two 0.5-mm-thick sections can be created with narrower collimation.

View larger version (31K): [in a new window]   Figure 4c.   Cross-sectional profile of an unequal-width detector design. (a) To acquire four 5-mm-thick sections, all eight detectors are activated. The signals from the detectors are combined into four channels, each representing a 5-mm-thick virtual detector. (b) To acquire four 2.5-mm-thick sections, the inner six detectors are activated. (c) To acquire four 1-mm-thick sections, pre- and postpatient collimators cover the outer one-third of the 1.5-mm-wide detectors. (d) Two 0.5-mm-thick sections can be created with narrower collimation.

View larger version (27K): [in a new window]   Figure 4d.   Cross-sectional profile of an unequal-width detector design. (a) To acquire four 5-mm-thick sections, all eight detectors are activated. The signals from the detectors are combined into four channels, each representing a 5-mm-thick virtual detector. (b) To acquire four 2.5-mm-thick sections, the inner six detectors are activated. (c) To acquire four 1-mm-thick sections, pre- and postpatient collimators cover the outer one-third of the 1.5-mm-wide detectors. (d) Two 0.5-mm-thick sections can be created with narrower collimation.

View larger version (51K): [in a new window]   Figure 5a.   Anatomic coverage. (a, b) The coverage for multisection CT (a) can be eight times longer than for single-section helical CT (b) at the same pitch and section thickness. (c, d) To scan the same volume in the same time with single-section helical CT, one must increase the pitch (c) or section thickness (d), thereby degrading image quality. (e) To achieve the same image quality with single-section helical CT, the scanning time would have to be lengthened eightfold.

View larger version (21K): [in a new window]   Figure 5b.   Anatomic coverage. (a, b) The coverage for multisection CT (a) can be eight times longer than for single-section helical CT (b) at the same pitch and section thickness. (c, d) To scan the same volume in the same time with single-section helical CT, one must increase the pitch (c) or section thickness (d), thereby degrading image quality. (e) To achieve the same image quality with single-section helical CT, the scanning time would have to be lengthened eightfold.

View larger version (42K): [in a new window]   Figure 5c.   Anatomic coverage. (a, b) The coverage for multisection CT (a) can be eight times longer than for single-section helical CT (b) at the same pitch and section thickness. (c, d) To scan the same volume in the same time with single-section helical CT, one must increase the pitch (c) or section thickness (d), thereby degrading image quality. (e) To achieve the same image quality with single-section helical CT, the scanning time would have to be lengthened eightfold.

View larger version (47K): [in a new window]   Figure 5d.   Anatomic coverage. (a, b) The coverage for multisection CT (a) can be eight times longer than for single-section helical CT (b) at the same pitch and section thickness. (c, d) To scan the same volume in the same time with single-section helical CT, one must increase the pitch (c) or section thickness (d), thereby degrading image quality. (e) To achieve the same image quality with single-section helical CT, the scanning time would have to be lengthened eightfold.

View larger version (52K): [in a new window]   Figure 5e.   Anatomic coverage. (a, b) The coverage for multisection CT (a) can be eight times longer than for single-section helical CT (b) at the same pitch and section thickness. (c, d) To scan the same volume in the same time with single-section helical CT, one must increase the pitch (c) or section thickness (d), thereby degrading image quality. (e) To achieve the same image quality with single-section helical CT, the scanning time would have to be lengthened eightfold.

View larger version (147K): [in a new window]   Figure 6.   Isotropic viewing. Coronal reformation image of the right temporal bone created from an axial multisection CT acquisition (0.5-mm section thickness, 0.2-mm longitudinal reconstruction interval) shows the oval window (1), horizontal segment of the facial nerve (2), incus (3), scutum (4), lateral semicircular canal (5), superior semicircular canal (6), vestibule (7), internal auditory canal (), and basal turn of the cochlea (8).

View larger version (160K): [in a new window]   Figure 7a.   Isotropic imaging of the ankle (0.5-mm section thickness, 0.2-mm longitudinal reconstruction interval) with MPR. (a) Coronal MPR image clearly shows a pin penetrating the posterior subtalar joint (arrowheads). (b) Sagittal MPR image clearly shows secondary degenerative changes (arrows). Streak artifacts are remarkably mild given the large amount of steel.

View larger version (158K): [in a new window]   Figure 7b.   Isotropic imaging of the ankle (0.5-mm section thickness, 0.2-mm longitudinal reconstruction interval) with MPR. (a) Coronal MPR image clearly shows a pin penetrating the posterior subtalar joint (arrowheads). (b) Sagittal MPR image clearly shows secondary degenerative changes (arrows). Streak artifacts are remarkably mild given the large amount of steel.

View larger version (140K): [in a new window]   Figure 8a.   Thin-section CT of the hip (1.0-mm section thickness, 0.5-mm longitudinal reconstruction interval). (a, b) Coronal (a) and curved oblique sagittal (b) reformation images show fine detail. (c) Lateral surface-rendered image shows the acetabulum and femur together. Surface rendering also can be used to show these structures separately.

View larger version (107K): [in a new window]   Figure 8b.   Thin-section CT of the hip (1.0-mm section thickness, 0.5-mm longitudinal reconstruction interval). (a, b) Coronal (a) and curved oblique sagittal (b) reformation images show fine detail. (c) Lateral surface-rendered image shows the acetabulum and femur together. Surface rendering also can be used to show these structures separately.

View larger version (133K): [in a new window]   Figure 8c.   Thin-section CT of the hip (1.0-mm section thickness, 0.5-mm longitudinal reconstruction interval). (a, b) Coronal (a) and curved oblique sagittal (b) reformation images show fine detail. (c) Lateral surface-rendered image shows the acetabulum and femur together. Surface rendering also can be used to show these structures separately.

View larger version (163K): [in a new window]   Figure 9a.   Postoperative evaluation of left sacroiliac arthrodesis with multisection CT (2.0-mm section thickness, 1.0-mm longitudinal reconstruction interval). (a) Coronal maximum-intensity projection image shows the sacrum with metal appliances. (b) Curved reformation image shows the sacroiliac joint surfaces and bone grafts (arrow).

View larger version (146K): [in a new window]   Figure 9b.   Postoperative evaluation of left sacroiliac arthrodesis with multisection CT (2.0-mm section thickness, 1.0-mm longitudinal reconstruction interval). (a) Coronal maximum-intensity projection image shows the sacrum with metal appliances. (b) Curved reformation image shows the sacroiliac joint surfaces and bone grafts (arrow).

View larger version (126K): [in a new window]   Figure 10.   Decreased range of motion of the right elbow in a 10-year-old boy after trauma. Sagittal reformation image from double-contrast multisection CT arthrography (1.0-mm section thickness, 0.5-mm longitudinal reconstruction interval) shows deformities of the proximal radial epiphysis and distal humerus and radial subluxation. A 5-mm defect (arrow) in the articular cartilage of the radial head is seen.

View larger version (154K): [in a new window]   Figure 11a.   Chronic sinusitis imaged with multisection CT (1.0-mm section thickness). (a) Sagittal image obtained with image viewing software (SurView; Surdex, St Louis, Mo) shows that the multisection acquisition will avoid dental hardware and the associated artifacts. (b, c) Coronal (b) and sagittal (c) reformation images show mucoperiosteal thickening.

View larger version (136K): [in a new window]   Figure 11b.   Chronic sinusitis imaged with multisection CT (1.0-mm section thickness). (a) Sagittal image obtained with image viewing software (SurView; Surdex, St Louis, Mo) shows that the multisection acquisition will avoid dental hardware and the associated artifacts. (b, c) Coronal (b) and sagittal (c) reformation images show mucoperiosteal thickening.

View larger version (107K): [in a new window]   Figure 11c.   Chronic sinusitis imaged with multisection CT (1.0-mm section thickness). (a) Sagittal image obtained with image viewing software (SurView; Surdex, St Louis, Mo) shows that the multisection acquisition will avoid dental hardware and the associated artifacts. (b, c) Coronal (b) and sagittal (c) reformation images show mucoperiosteal thickening.

View larger version (93K): [in a new window]   Figure 12a.   Postfusion degenerative disease imaged with CT myelography (1.0-mm section thickness). (a) Sagittal reformation image shows excellent bone detail and the outline of the subarachnoid space. (b, c) Corrected-axis MPR image (b), which was obtained along the dashed line in a, has the same spatial resolution as an original axial image (c), which was obtained along the black line in a.

View larger version (107K): [in a new window]   Figure 12b.   Postfusion degenerative disease imaged with CT myelography (1.0-mm section thickness). (a) Sagittal reformation image shows excellent bone detail and the outline of the subarachnoid space. (b, c) Corrected-axis MPR image (b), which was obtained along the dashed line in a, has the same spatial resolution as an original axial image (c), which was obtained along the black line in a.

View larger version (91K): [in a new window]   Figure 12c.   Postfusion degenerative disease imaged with CT myelography (1.0-mm section thickness). (a) Sagittal reformation image shows excellent bone detail and the outline of the subarachnoid space. (b, c) Corrected-axis MPR image (b), which was obtained along the dashed line in a, has the same spatial resolution as an original axial image (c), which was obtained along the black line in a.

View larger version (141K): [in a new window]   Figure 13a.   Duodenal carcinoma. Pancreatic and portal venous-phase scans (2.5-mm section thickness, 1.3-mm longitudinal reconstruction interval) yield images with good low-contrast resolution. (a-c) Axial (a), coronal (b), and sagittal (c) images show a dilated common bile duct (I) and a duodenal neoplasm (arrows). (d, e) Lateral arterial-phase (d) and anterior venous-phase (e) maximum-intensity projection images show normal vessels.

View larger version (179K): [in a new window]   Figure 13b.   Duodenal carcinoma. Pancreatic and portal venous-phase scans (2.5-mm section thickness, 1.3-mm longitudinal reconstruction interval) yield images with good low-contrast resolution. (a-c) Axial (a), coronal (b), and sagittal (c) images show a dilated common bile duct (I) and a duodenal neoplasm (arrows). (d, e) Lateral arterial-phase (d) and anterior venous-phase (e) maximum-intensity projection images show normal vessels.

View larger version (136K): [in a new window]   Figure 13c.   Duodenal carcinoma. Pancreatic and portal venous-phase scans (2.5-mm section thickness, 1.3-mm longitudinal reconstruction interval) yield images with good low-contrast resolution. (a-c) Axial (a), coronal (b), and sagittal (c) images show a dilated common bile duct (I) and a duodenal neoplasm (arrows). (d, e) Lateral arterial-phase (d) and anterior venous-phase (e) maximum-intensity projection images show normal vessels.

View larger version (127K): [in a new window]   Figure 13d.   Duodenal carcinoma. Pancreatic and portal venous-phase scans (2.5-mm section thickness, 1.3-mm longitudinal reconstruction interval) yield images with good low-contrast resolution. (a-c) Axial (a), coronal (b), and sagittal (c) images show a dilated common bile duct (I) and a duodenal neoplasm (arrows). (d, e) Lateral arterial-phase (d) and anterior venous-phase (e) maximum-intensity projection images show normal vessels.

View larger version (113K): [in a new window]   Figure 13e.   Duodenal carcinoma. Pancreatic and portal venous-phase scans (2.5-mm section thickness, 1.3-mm longitudinal reconstruction interval) yield images with good low-contrast resolution. (a-c) Axial (a), coronal (b), and sagittal (c) images show a dilated common bile duct (I) and a duodenal neoplasm (arrows). (d, e) Lateral arterial-phase (d) and anterior venous-phase (e) maximum-intensity projection images show normal vessels.

View larger version (75K): [in a new window]   Figure 14.   Bilateral carotid artery stenosis. Coronal maximum-intensity projection image from CT angiography performed from the arch to the skull base (1.0-mm section thickness, 19-cm longitudinal coverage, 0.5-mm longitudinal reconstruction interval) shows severe stenosis of the left internal carotid artery (arrow).

View larger version (40K): [in a new window]   Figure 15a.   CT angiography performed from the aortic arch to the ankles (2.5-mm section thickness). Coronal maximum-intensity projection images obtained before (a) and after (b-d) bone subtraction show occlusion of the right iliac artery and both femoral arteries with reconstitution of the popliteal arteries (arrows in c) and good runoff below the knees (d).

View larger version (40K): [in a new window]   Figure 15b.   CT angiography performed from the aortic arch to the ankles (2.5-mm section thickness). Coronal maximum-intensity projection images obtained before (a) and after (b-d) bone subtraction show occlusion of the right iliac artery and both femoral arteries with reconstitution of the popliteal arteries (arrows in c) and good runoff below the knees (d).

View larger version (129K): [in a new window]   Figure 15c.   CT angiography performed from the aortic arch to the ankles (2.5-mm section thickness). Coronal maximum-intensity projection images obtained before (a) and after (b-d) bone subtraction show occlusion of the right iliac artery and both femoral arteries with reconstitution of the popliteal arteries (arrows in c) and good runoff below the knees (d).

View larger version (73K): [in a new window]   Figure 15d.   CT angiography performed from the aortic arch to the ankles (2.5-mm section thickness). Coronal maximum-intensity projection images obtained before (a) and after (b-d) bone subtraction show occlusion of the right iliac artery and both femoral arteries with reconstitution of the popliteal arteries (arrows in c) and good runoff below the knees (d).

View larger version (123K): [in a new window]   Figure 16a.   Renal artery stenosis in a hypertensive patient imaged with CT angiography (1.0-mm section thickness). (a) Coronal shaded-surface display image shows a patent aortobiiliac bypass graft (arrows) and a right iliac to left renal artery bypass graft (arrowhead). (b) A 20° oblique maximum-intensity projection image shows severe renal artery stenosis (arrow), which was missed on a preoperative conventional arteriogram.

View larger version (73K): [in a new window]   Figure 16b.   Renal artery stenosis in a hypertensive patient imaged with CT angiography (1.0-mm section thickness). (a) Coronal shaded-surface display image shows a patent aortobiiliac bypass graft (arrows) and a right iliac to left renal artery bypass graft (arrowhead). (b) A 20° oblique maximum-intensity projection image shows severe renal artery stenosis (arrow), which was missed on a preoperative conventional arteriogram.

View larger version (112K): [in a new window]   Figure 17.   Preoperative imaging of a renal donor. Oblique anterior CT angiogram (1.0-mm section thickness, pitch of 1.4, 0.5-mm longitudinal reconstruction interval) shows two right renal arteries (arrows).

View larger version (142K): [in a new window]   Figure 18a.   Endovascular repair of an aortic aneurysm with stent-grafts. Preoperative (a) and postoperative (b) oblique shaded-surface display images clearly show the relationship between the metallic stent and the renal arteries (arrow).

View larger version (142K): [in a new window]   Figure 18b.   Endovascular repair of an aortic aneurysm with stent-grafts. Preoperative (a) and postoperative (b) oblique shaded-surface display images clearly show the relationship between the metallic stent and the renal arteries (arrow).

View larger version (124K): [in a new window]   Figure 19a.   Coronary calcium scoring. Axial images obtained with prospective electrocardiographic gating and a temporal resolution of 0.3 second show calcifications (arrows) in the right coronary artery (a) and left anterior descending artery (b).

View larger version (105K): [in a new window]   Figure 19b.   Coronary calcium scoring. Axial images obtained with prospective electrocardiographic gating and a temporal resolution of 0.3 second show calcifications (arrows) in the right coronary artery (a) and left anterior descending artery (b).

View larger version (152K): [in a new window]   Figure 20a.   Acute stroke. Axial color-mapped images of total perfusion (a) and time to peak perfusion (b) show decreased flow and a delayed time to peak in the right frontal and temporal lobes. The regions of interest define areas for measurements not presented herein. A nonenhanced CT scan was normal. (Courtesy of Thorsten Fleiter, MD, University of Ulm, Germany.)

View larger version (154K): [in a new window]   Figure 20b.   Acute stroke. Axial color-mapped images of total perfusion (a) and time to peak perfusion (b) show decreased flow and a delayed time to peak in the right frontal and temporal lobes. The regions of interest define areas for measurements not presented herein. A nonenhanced CT scan was normal. (Courtesy of Thorsten Fleiter, MD, University of Ulm, Germany.)

View larger version (143K): [in a new window]   Figure 21a.   Imaging of a large patient (290 lb [130 kg], chest circumference of 54 inches [135 cm]) with suspected pulmonary emboli. (a) Coronal image obtained with image viewing software (SurView) shows that the left arm is down (arrows). (b) Axial image (2.5-mm section thickness, pitch of 0.8, 1.2-mm longitudinal reconstruction interval) is of high quality and shows no emboli, a result confirmed at pulmonary arteriography performed 2 days later. Multisection technology allows pitch values of less than 1, increasing the effective milliampere-second value per section and thereby improving image quality.

View larger version (135K): [in a new window]   Figure 21b.   Imaging of a large patient (290 lb [130 kg], chest circumference of 54 inches [135 cm]) with suspected pulmonary emboli. (a) Coronal image obtained with image viewing software (SurView) shows that the left arm is down (arrows). (b) Axial image (2.5-mm section thickness, pitch of 0.8, 1.2-mm longitudinal reconstruction interval) is of high quality and shows no emboli, a result confirmed at pulmonary arteriography performed 2 days later. Multisection technology allows pitch values of less than 1, increasing the effective milliampere-second value per section and thereby improving image quality.

View larger version (159K): [in a new window]   Figure 22a.   Imaging of a severely overweight patient with chest pain. (a) Coronal image obtained with image viewing software (SurView) shows that the left arm is down (arrows) due to recent surgery. (b, c) Oblique (b) and curved (c) MPR images show aortic dissection. Note the nonperfused left kidney (arrowheads).

View larger version (146K): [in a new window]   Figure 22b.   Imaging of a severely overweight patient with chest pain. (a) Coronal image obtained with image viewing software (SurView) shows that the left arm is down (arrows) due to recent surgery. (b, c) Oblique (b) and curved (c) MPR images show aortic dissection. Note the nonperfused left kidney (arrowheads).

View larger version (87K): [in a new window]   Figure 22c.   Imaging of a severely overweight patient with chest pain. (a) Coronal image obtained with image viewing software (SurView) shows that the left arm is down (arrows) due to recent surgery. (b, c) Oblique (b) and curved (c) MPR images show aortic dissection. Note the nonperfused left kidney (arrowheads).

View larger version (186K): [in a new window]   Figure 23a.   Virtual endoscopy. (a) Image from CT colonography of the entire colon and rectum (2.5-mm section thickness), which is performed in 20 seconds. (b, c) Endoscopic (b) and coronal shaded-surface display (c) images show a bronchial stricture (arrow). (d, e) Images from virtual arterioscopy show the aorta before (d) and after (e) endoluminal repair with a metallic stent-graft.

View larger version (151K): [in a new window]   Figure 23b.   Virtual endoscopy. (a) Image from CT colonography of the entire colon and rectum (2.5-mm section thickness), which is performed in 20 seconds. (b, c) Endoscopic (b) and coronal shaded-surface display (c) images show a bronchial stricture (arrow). (d, e) Images from virtual arterioscopy show the aorta before (d) and after (e) endoluminal repair with a metallic stent-graft.

View larger version (92K): [in a new window]   Figure 23c.   Virtual endoscopy. (a) Image from CT colonography of the entire colon and rectum (2.5-mm section thickness), which is performed in 20 seconds. (b, c) Endoscopic (b) and coronal shaded-surface display (c) images show a bronchial stricture (arrow). (d, e) Images from virtual arterioscopy show the aorta before (d) and after (e) endoluminal repair with a metallic stent-graft.

View larger version (202K): [in a new window]   Figure 23d.   Virtual endoscopy. (a) Image from CT colonography of the entire colon and rectum (2.5-mm section thickness), which is performed in 20 seconds. (b, c) Endoscopic (b) and coronal shaded-surface display (c) images show a bronchial stricture (arrow). (d, e) Images from virtual arterioscopy show the aorta before (d) and after (e) endoluminal repair with a metallic stent-graft.

View larger version (169K): [in a new window]   Figure 23e.   Virtual endoscopy. (a) Image from CT colonography of the entire colon and rectum (2.5-mm section thickness), which is performed in 20 seconds. (b, c) Endoscopic (b) and coronal shaded-surface display (c) images show a bronchial stricture (arrow). (d, e) Images from virtual arterioscopy show the aorta before (d) and after (e) endoluminal repair with a metallic stent-graft.

View larger version (159K): [in a new window]   Figure 24a.   Multisection CT of the brain (1.0-mm section thickness). The 304 source images obtained from the scan were added to form 5-mm-thick sections. (a, b) Original 1-mm-thick section (a) has more noise than a reconstructed 5-mm-thick section (b). (c, d) Coronal (c) and sagittal (d) views are created from the source images. The encephalomalacia (arrows) is a sequela of an old hemorrhage.

View larger version (154K): [in a new window]   Figure 24b.   Multisection CT of the brain (1.0-mm section thickness). The 304 source images obtained from the scan were added to form 5-mm-thick sections. (a, b) Original 1-mm-thick section (a) has more noise than a reconstructed 5-mm-thick section (b). (c, d) Coronal (c) and sagittal (d) views are created from the source images. The encephalomalacia (arrows) is a sequela of an old hemorrhage.

View larger version (166K): [in a new window]   Figure 24c.   Multisection CT of the brain (1.0-mm section thickness). The 304 source images obtained from the scan were added to form 5-mm-thick sections. (a, b) Original 1-mm-thick section (a) has more noise than a reconstructed 5-mm-thick section (b). (c, d) Coronal (c) and sagittal (d) views are created from the source images. The encephalomalacia (arrows) is a sequela of an old hemorrhage.

View larger version (156K): [in a new window]   Figure 24d.   Multisection CT of the brain (1.0-mm section thickness). The 304 source images obtained from the scan were added to form 5-mm-thick sections. (a, b) Original 1-mm-thick section (a) has more noise than a reconstructed 5-mm-thick section (b). (c, d) Coronal (c) and sagittal (d) views are created from the source images. The encephalomalacia (arrows) is a sequela of an old hemorrhage.