CT Teaching Manual: A Systematic Approach to CT Reading, 4th ed. By Mattias Hofer. New York, NY: Thieme Medical, pp., $ softcover (ISBN. HOFER - CT Teaching Manual - A Systematic Approach to CT Reading, 2nd Ed. - Ebook download as PDF File .pdf), Text File .txt) or read book online. Thieme is an award-winning international medical and science publisher serving health professionals and students for more than years.
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CT Teaching Manual 3rd edition. Home · CT Teaching 44MB Size Report. DOWNLOAD PDF Teaching atlas of mammography 3rd Edition. Read more. This is the first English-language edition of an introduc- tory computed tomographic (CT) manual previously published in Germany. Its stated goals include. OVERVIEW. The text CT Teaching Manual: A Systematic Approach to. CT Reading was written for medical students, technologists, interns, and residents, or.
After an oral contrast agent. The images are displayed as seen from below caudal view and consequently are laterally reversed. In Figure The pituitary gland and stalk are seen between the upper border of the sphenoid sinus 73 and the clinoid process Even the pericallosal artery The main probl em is the long period of latency beforethethyrotoxicosis crisis becomes manifest.
Fundamentals of Body CT 3rd Edition. Read more. Teaching atlas of mammography 3rd Edition. Manual of Emergency Airway Management 3rd Edition. The Missing Manual, 3rd Edition. Manual of Cardiovascular Medicine, 3rd Edition. Manual of Equine Reproduction, 3rd Edition. Principles of Manual Medicine 3rd Edition. Solution Manual to Microeconomic Analysis, 3rd Edition.
Pediatric Body CT, 2nd Edition. Sectional Anatomy: Physics Laboratory Manual 3rd Ed. Ideal for residents starting in radiology and radiologic technologists, this concise manual is the perfect introduction to the physics and practice of CT and the interpretation of basic CT images.
Designed as a systematic learning tool, it introduces the use of CT scanners for all organs, and includes positioning, use of contrast media, representative CT scans of normal and pathological findings, explanatory drawings with keyed anatomic structures, and an overview of the most important measurement data.
Finally, self-assessment quizzes - including answers - at the end of each chapter help the reader monitor progress and evaluate knowledge gained.
New in this fourth edition: Radiology , Radiological Technology , Diagnostic Imaging. Rate this product. Please log In to rate. Also Recommended. Asian Journal of Oncology. Veterinary and Comparative Orthopaedics and Traumatology. In the plane of Figure Usually only the part of the septum located between the two anterior horns of the lateral ventricles Fig. Refresh your anatomic skills by naming all other structures in Figure Please review the normal scans in Figures Involuntary movements of the head can be kept at a minimum by soft padding.
By comparing this plane with the adjacent one below it Fig. If the head is tilted even slightly during the scan procedure. The exact position of the nose in an a. Oniy its roof will appear. In ventilated or unconscious patients an additional immobilization of the head with suitable bandings may be necessary. The computer therefore calculates a blurred. In this example the bones of the:. Such artifacts would not appear in MR images of these levels. Many injured patients cannot be expec?
C base caused the hyperdense partial volume effect. Please note the considerable beam hardening bone artifacts 3 overlapping the brain stem Contusions with subcutaneous hematomas 8 may. After complete resorption of a hematoma Fig. Possible complications of such leakage or of a subarachnoid hemorrhagearedisturbed eSFcirculationcaused byobstruction of the pacchionian granulations.
Cranial Pathology Intracranial Hemorrhage 54 After having discussed that partialvolume effects dueto asymmetricprojections i. In anemic patients the hematoma is less dense and may therefore appear isodense to normal brain. An hydrocephalus with increased intracranial pressure and transtentorial herniation of the brain may result. A eeT obtained im mediately after skull trauma which does not show any pathologic changes is therefore not a good predictor since deiayed cerebral bleeding cannot be ruled out.
A foilow-up scan should be obtained if the patient's condition deteriorates. Type of bleeding Characteristics Subarachnoid bleeding Hyperdense blood in the subarachnoid space or the basal cisterna instead of hypodense eSF Fresh hematoma: Quite frequently this in turn causes obstruction of the contralateral foramen of Monro resulting in unilateral dilation of the lateral ventricle on the side opposite thebleeding Fig.
Bleeding Caused by a Contusion As a direct consequence of skull trauma. The characteristicsuseful in differential diagnosis of the various types of intracranial bleeding are listed in Table An acute hemorrhage 8 appears as a hyperdense mass which may be accompanied by surrounding edema and displacement of adjacent brain tissue.
Epidural and subdural hematomas can also lead to major displacement of brain tissue and to midline shifts. Acute edema is thereforenot presenl yet. In this case the 3rd ventricle is completely filled with clotted blood. Please note the edema surroun. The patient is in danger of transtentorial herniation if the ambient cistern is effaced Fig.. In such cases it is important to havea closer look at the width of the SAS overthe. In the present case though.
In contrast to an epidural hematoma. It is thereforenot as important. Hematomas with the propensity to expand.
The only identifiable sign may be a small hyperdense area adjacent to the falx Subdural Hematoma Bleeding into thesubduralspace results from cerebral contusions. In adults a small subarachnoid hemorrhage alsocauses only a minor. This kind of bleeding is notconfined by cranial sutures and may spread along the entire convexity of the hemisphere.
At the timeofthisCTscan the bleeding was soslight that it had not yet caused anydisplacement of brain tissue. The hematoma initially appears asa long. The danger involved in a small. Subdural hematomas can also cause marked displacement of brain tissue Fig. It is difficultto determine whether the bilateral. Arterial hemorrhage lifts the dura from the inner surface of the cranium 55 and then appears as a biconvex. Cranial Pathology Intracranial Hemorrhage 57 Extradural Hematomas Bleedings into the extradural spaces are usually caused by dam age to the middle meningeal artery.
Use the free space below the picture: Inthis case the distortion of the midline was caused by the right-sided. Exercise 8: Space for your suggested answer: Predisposed areas are temporoparietal regions or sometimes the posterior cranial fossa. In small extradural hematomas 8 the biconvex shape is not distinct Fig.
The hematoma does not extend beyond the sutures between the frontal 55a. It is important to distinguish between a closed skull fracture with an intact dura. An unequivocal sign of a compound skull fracture Fig. In this case the infarction Is 2 weeks old and necrotic tissue has been mostly resorbed and replaced by CSF. Old emboli result in small. A CT scan shoulc be repeated if the initial scan does not show any pathologicchanges even though the patient is symptomatic and if symptoms de notresolve resolution of symptoms points to a transient ischemic attack.
Vascular occlusion develops in association with atherosclerotic changes of cerebral arteries or. Cranial Pathology Stroke 58 Apart from cardiovascular and malignant diseases. If the area of infarction corresponds to the distribution of a cerebral artery. In classical infarctions of branches of the middle cerebral artery.
Adiffuse pattern of defects calls forcolor flow Doppler imaging or carotid angiographyand an ecnocaroiocramto exclude atrial thrombus. In case of aTIA: Please remember that in a suspected stroke it might take up te 30 hours to distinguish clearly the accompanying edema as " hypodense lesion from unaffected brain tissue.
The unenhanced follow-up CT scan in Figure A further cause are blood clots from the left heart or thrombotic plaques from the carotid bifurcation which embolize into a cerebral vessel. Such areas are called lacunal infarcts Fig. In contrast to theTIA. Incaseof embolization. Athrombus occludes a cerebral artery. Smaller areas of infarction do not usually show any significant midline shift.
If the arterial walls are damaged. Did you also spot the second. CM the lesion in the left hem isphere 7 is clearly demarcated Fig. Even small areas in which the blood-brain barrier is disturbed become visible Fig. In the unenhanced image Fig. The post-CM image. The differential diagnosis of brain tumors is made much easier by the injection of i.
After l. Large metastases sometimes cause surrounding edema which could be misinterpreted as infarct-related edema on unenhanced images if the metastasis appears isodense to the adjacent tissue.
They typically have a broad base on the wall of a paranasal sinus. Bacteria from the aortic valve caused this septic embolism in the leff occipital lobe. Such cysts are only of significance if they obstruct the infundibulum 0 of the maxillary sinus or the semilunar canal.
Swelling of the mucous membranes of the external auditory canal 63b is visible without the need for CM.
Haller's cells ". Contrast medium Fig. In patients with chronic sinusitis. Aretention cyst. CM is the demonstration of inflammatory processes. Withprogressing abscess formation. Cranial Pathology Inflammatory Processes 60 Another example of the advantages of i. All of these variations can obstruct the semilunar canal and cause chronic. Endocrine Ophthalmopathy Minimal discrete changes can be missed during the reporting of a CT scan: The disease will continue and affect the medial rectus muscie 47cl.
In this case it causes a minor proptosis. The first findin g is an increase in the volume of the inferior rectus muscle 47b. Every mass within the orbit should. In order not to miss tumor invasion into the walls of the orbit. There will etten be a typical temporal pattern of involvement. Myositis should be considered inthe differential diagnosis. For planning aresection.
Originatingfromthe mucous membranes of the right maxillary sinus It is therefore useful to examine both the soft tissue and bone windows. Thefollowingexample shows a tumor of the paranasal sinuses 7 in an axial Fig.
Another important question is whether or not the head of the mandible 58a in Fig. Diagnosis of the fracture in Figure Involving the lateral wall of the orbit and the frontal process of the maxilla to the contralateral side. In this case. The axial images are obtained and printed as viewed from caudally so the right lobe of the thyroid is imaged to the left of the trachea. Inspiral CT. Malignant and inflammatory processes can be depicted more accurately with the aid of CM.
During neck imaging. For cervical CTs there is also no 'one and only' approach. Usually sections of the neck are obtained using a mm thickness. Whenever there is no contraindication. CT examinations of the neck are carried out afteri.
The checklist presented here was deveioped through experience and is just one of many options forthe beginner. Condition and clarity of fat? Normal perfusion of vessels? Thromboses or atherosclerotic stenoses? Symmetry and definition of salivary glands?
Thyroid parenchyma homogeneous and without nodules? Any focal pathologic enhancement with CM? Narrowing of the tracheal lumen? Assessment of lymph nodes? Number and size? Cervical vertebrae examined in bone window? Vertebral canal patent or narrowed? Adequate enhancement of cervical vessels requires higher doses of CMthan.
The radiologist must remember to check images at bone windows on the screen for fractures or lytic lesions. It may be necessary to carry out a second acq uisition at anotherangle Fig. There are specific recommendations and suggested schemes for CM injection at the end of the manual. Cervical CT 64 axial levels and gantry angulation aredeterminedfrom this topogram Fig. Each examiner is free tosetup hisorher own checklist and strategy. As the thoracic inlet is approached during the scanning.
The transverse Images should be obtained with a small-scan field-of-view to optimize detail in smaller structures in the neck.
Readers who ant more anatomic detail should consult the relevant literature: Thecranial sections Figs.. Lateral to the mand ible Single muscles have little clinical relevance and thus. The spread of inflammatory processes within the cervical connectivetissue spacesis restri cted within com partments defined bythe cervical fascia .
Dorsal to the pharynx lie the longus capitis and longus cervicis muscles We havetherefore reduced the amount: The different layers of the cervical fascia are explained on the following page Fig. Cervical CT Normal Anatomy The thin superficial muscle is the platysma Atthe level of theparotid gland there is a similar barrier consisting of the sagittal septum which splits a retropharyngeal from a parapharyn geal space. Inflammations originating furth er dorsal. The parotid gland is situated cranial and posterior to the submandibular gland next to the mandible The pharyn x is surrounded by Waldeyer's rin g of tonsillartissue 1 Cervical CT Normal Anatomy 66 Further caudally the following cervical muscles become visible beneath the trapezius muscle Underthe tongue the floor of the mouth is organized in layers.
Note that the carotid bulb is situated between Figures From cranial to caudal are: Cervical CT Normal Anatomy 68 The bifurcation of the common carotid artery 85 is an area of predilection for atherosclerotic plaques Fig. Always check for degenerative changes at the margins of the bodies of cervical vertebrae 50 orforherniated discswhichmight narrow the spinal canal containing the cervical cord Note the positions of the cricoid and arytenoid carti lages at the rim a glottidis In these normal individuals.
On either side of the trachea 81 lie the two lobes of the thyroid gland Cervical CT Normal Anatomy 69 se of its iodine content.. As a rule. Beginners occasionally mistake the esophagus In case of doubt. The muscles ofthe I girdle as well as the shoulder joints therefore appear in unfamiliar positions. Large lymphomas 7 orconglomerate LN masses Fig.
Note also the atherosclerotic plaques or thromboses in the lumen of the carotid artery 85 asin Figure Abscesses typically infiltrate the surrounding adipose tissue with a streaky pattern of edema so that structures such as arteries.
These appearances are sosimilar to large hematomas or necrotic tumors that a differential diagnosis may be difficult without a detailed clinical history. In immune-suppressed patients. Compare the scans in Figures It is sometimes difficult to distinguish them from abscesses with central necrosis asshown.
A benign struma 83 may extend into retrosternal regions and laterally displace supra-aortic vessels After partial resection of a struma Fig. If the thyroid is enlarged.
The tracheal walls 81 are compressed and may become infiltrated. The total volume. Iy and 4. In this case the left internal jugular vein was also removed and the lumen of the right one 86a is therefore larger than normal.. Cervical Pathology Thyroid Gland In our experience these littletests will help you to remember better what you have learn ed.
Repeat this exercise occasionally until you can doit with ease. Type of hemorrhage: That way you will notsee answers to questions you haven't tackled yet.
The questions become increasingly difficult as you goalong: Whydid you choose these settings? With which kindsof hemorrhage are you fami liar? How can you differentiate between them in CT morphology? What complicationsor consequences must you particularly watch out for consult pp. Do not settle for the most obvious find it? After havinq noted it.
It is much more effective to look up each gap inyour knowledge as it occurs than to skip a problem and turn directlytothe answer. It will keep you in suspense! Compare your sketch with Figures Which window setting window center and window width in HU would you select for an optimal brain CT? Before beginning the examination.
You should therefore only turn to the answers at the back of the book when you have solved each problem byyourself. What do you really discovered all pathologic features. Make the most of this opportunity for self-assessment and take it in good grace if you find you missed something.
Don't give up too quickly! Ii2t Is there any feature in this orbital scan Fig. Note your observations below. Make a note of your tentative diagnosis and how you would proceed. How many fresh hemorrhages Fig. What is your differential diagnosis? Which of them is the most probable diagnosis? Which additional information could also be helpful? Isthere a pathologic abnormality? Or is it simply an artifact or even a normal finding?
The eeT in Figure These tissues should therefore be evaluated first. Systematic Sequencefor Readings The beginner often forgets to check the softlissues of the thoracic wall because the examination of themediastinum and the lungs is Since thepleural window is very wide.
Sections 10 mm thick will overlap by 1 mm. In order not to miss any pathologic changes within the lung review p. Common sitesof abnormality are the breasts and fat in the axilla 2.
Again the large number of images necessitates a systematictechniqueforevaluation soas not towastetimelooking randomly back and forth between them. More or less spherical solid masses may indicate intrapulmonary metastases.
Thoracic CT 74 After havingdiscussed normal anatomy ofcaudal cervical sections p. After this-also using soft-tissue windows.
When examining the lung vessels. On the soft-tissue window: Fromthis point cranially. It is essential to differentiate between cross-sectioned vessels and solid masses by comparing adjacent levels ct. Anteriorto theaortic arch 89b LNs of normal size are rarely seen in the CT. Pulmonary oligemiaisnormal onlyalong the margins ofthe lobes and in the periphery. The evaluation of the soft-tissue window is complete when the heart any coron ary sclerosis.
Each image can therefore be viewed at two different window settings. Consult the lung chapteron pages 84ff. The easiest approach is to orient yourself relative to the arch of the aorta 89b. Only now should the radiologist turn to the lung or pleural window. Checklist for Thorax Readings. It is therefore possible to evaluate bone structure in addition to the pulmonary vasculature. The checklist will help you read thoracic CTs systematically. The presence of a fewLNs smaller than 1.
From this page on. A small topogram Fig. Selection of Image Plane As a rule. The simultaneous presentation of two window settings in onehard copy boththe lung and thesoft-tissue window has notproved practical because pathologic abnormalities which have densitylevels between the twowould beoverlooked.
On the lung window: Usuallythepectoralismajor 26a and minor 26b muscles are separated byathinlayer offat. If the arms are elevated. Asymmetry inthe diameter of thejuguiarvein 86 isseen quiteoften and has nopathoiogic significance. Orthogonally sectioned branches of the axillary 93 and iateral thoracic 95 vessels must be distinguished from axillary LNs.
The parenchyma ofthe thyroid gland 83 should appear homogeneous and clearly defined from the surrounding fat 2. The left lung 84 appears on the right side of the image and vice versa. Beginning at the aortic arch B9b in Fig. Atthe section in Figure In front of the subclavian artery lie the leftcom mon carotid artery 85 and the brachiocephalictrunk More to the right andanteriorly are the bracniocephalic veins 91 , which formthe superior venacava 92 at the levels of Figures In the fat of the axilla 2 , normal LNs 6 are often recognizable by their typical indented shape: At a different angle, the hypodense hilum will appear in the center of an oval.
Healthy LNs are well defined and should not exceed 1 em in diameter in this location Figs. Directly above the right main bronchus, it arches anteriorly into the superior vena cava 92 in Fig. Be sure not to confuse the paravertebral azygos vein , the hemiazygos vein or accessory hemiazygos a with paraaortic LNs Figs. Immediately caudal to the arch of the aorta 89b is situated the pu lmonary trunk 90 , which divides intothe right 90a and left 90b pulmonary arteries Fig.
At the level of Figures Also check for enlarged LNs or malignant masses in the subcarinal position between the two main bronchi 81 b close to the pulmonary vessels 96 Fig. Near the internal thoracic mammary vessels 94 lies the regional lym phatic drainage of themedial parts ofthe breasts, whereas the lymphatic drai nage of the lateral portions of the breasts is primarily to theaxillary nodes.
The main coronary arteries 77 are also distingu ishable in the epicardial fat 2 Fig. Ie esophagus 82 next to the descending aorta 89c so thatyou will later be able. Develop a clear mental picture of the positionsof the azygos vein and.
Only the larger central branches of the pulmonary vessels 96 can be seen on the soft-tissue window. The right atrium 74a lies on the right lateral side and the right ventricle 74b anteriorly behindthe sternum Note the junction between the hemiazygos vein and the azygos vein The smaller.
Exercise 1g: Write down a concise but complete sequence of all criteria for interpreting a thoracic CT. Only after this step has been carried out is the evaluation ofa chest CT complete.
Many radiologists who suspect the presence of a bronchial carcinoma BG obtain images to the caudal edge a the liver see p. The caliber of lung vessels near the periphery ofthe diaphragm is sosmall that they are not visibleon the soft-tissue window. The pattern of the pulmonary vasculatureshould therefore be examined on the lung windows. Then compareyour notes with the checklist on page 74 and repeat this exercise from time to time until you remember every criterion.
In the left lung. The borders of the segments. The right lung has 10 segments.
Normal Anatomy 84 Segments of the Lung It is especially important to be able to identifythe segmentsof the lungs in CT images if bron chioscopy is planned for biopsy or to remove a fore ign body. The catheter was positioned too peripherally and caused hemorrhage into adjacent parts of the lung.
At a dS setting of 10 mm this zone closeiy resembles the poorly ventilated area at the back of the posterior lobe HRCT distinguishes these areas of increased density more clearly Fig. HRCT is therefore not the method of choice for routine chest examination because radiation dosage is much higher if more sections are acquired.
Only structures with naturally highlevelsof contrast such as areas surrounding bone will be well demonstrated. In the SCT technique. Follow-up 3weeks latershowed completerecovery.
The image acquisition parameters can be adjusted on the console to a thickness of mm if necessary. Even conventional CT scanners can acquire images of narrower slice thickness than the standard mm. Longer examination times and higher hardcopy film cost "slice pollution" arealso arguments against using HRCT. Pathology 86 I High-Resolution Technique HRCT stands for high-resolution computed tomography using thin sections and a high spatial resolution reconstruction algorithm.
The DD includes bronchial carcinoma. Because the slices are extremely thin. Older scar tissue 1 86 is always well defined Fig. Areas of collapse and poor ontilation may then disappear or be seen anteriorly.
HRCT isoften the only method with. In dou btful cases. Pathology Pulmonary abnormalities due to an infiltrate or to a pneumoconiosis would be hanged.. Fresh infiltrates can sometimes be seen next to older scar tissue Fig.
It can pass from the posterior mediastinum through theright apical lobe to the superior vena cava An example isthe right subclavian artery. At the time of this follow-up CT. Note that normal breast tissue. Thesechanges are accompanied by a slight elevation of the diaphragm. In the patient imaged in Figure When using lung windows.
Figures Asymmetry in the broncnovascular pattern develops after a part of the lung has been resected. Atypical positions or branchingoftheaortic arch 89 vesselsare rarer. There are fewer lung vessels per unit volume and an ipsilateral shift of themediastinum.
It is located within a fold of the pleura and therefore separates theazygos lobe fromtheremainder of theright upper lobe. Thoracic Pathology Thorax Wall 89 ordingto the sequence in the checklist on page Such LNs all appear solid and lack the hilum fat sign. They often have central. SS with central liquefaction must be considered Fig. Again the lack of clinical information makes diagnosis unnecessarily difficult for the radiologist.
If lary lymph node metastases have been treated operativel y or " radiotherapy. They often have a hypodense center or arehorseshoe- shaped as in Figure Postoperative healing processes and scarring change the morphology of LNs Fig. Many abnormal LNs have lost their normal contours and are rounder or irregular.
Most abnormalities will be located in the ae and in the fem ale breast. For direct comparison. The malignant tissue crosses the fascial planes or infilt rates the thoracic wall. Osteolysis can. Special attention must therefore be paid tothe regional LNs ct. Advanced stages of breast cancer 7 have a solid. Thoracic Skeleton Osteolysis within the thoracic skeleton is not uncommon and is usually due to either metastases or a plasma cell tumor. The diagnosis of recurrent tumor is made more difficult by fibrosisafter radiation.
In addition to destructive processes cf. Bizarre shapes can often be seen Fig. The bone window must be exam ined in such cases. Baseline CT after mastectomy Fig. Thoracic Pathology Thorax Wall 90 Breast The normal parenchyma 72 of the female breast has very irregular contours and slender.