By T. Kurt. University of Maryland at College Park. 2018.
A larger study of CT buy discount avanafil 200 mg line, in which CT interpretation results were com- pared with surgical-pathologic ﬁndings order avanafil 200mg mastercard, showed the accuracy of CT was only 24% for capsular extension and 59% for seminal vesicle invasion (80) generic avanafil 200mg overnight delivery. Due to these discouraging results cheap avanafil 100 mg without a prescription, and to the higher accuracy of MRI in revealing the local extent of disease, CT has been largely abandoned as an initial test for evaluating local disease. Computed tomography may still have a role, however, in evaluating lymphatic metastases. Metastases may enlarge nodes, and since CT can evaluate nodal size well, it has become the primary modality for search- ing for nodal disease. It is well recognized that patients may have metasta- tic nodal disease from prostate cancer in which individual nodal deposits are sufﬁciently small that the overall node size is not enlarged, so that the sensitivity of the CT is considerably less than 100%. The studies of false- negative rates for CT in detecting nodal metastasis have reported sensi- tivities of only 0% to 7% (76,81,82). Careful dissection studies (83) have conﬁrmed that this is due to the relatively small size of many tumor- bearing nodes. Large nodes are felt to be a more accurate CT sign of metastatic disease than small ones are of disease without metastases; still, enlarged nodes (77,83) may occasionally be found in patients without metastatic disease. The occasional false-positive case notwithstanding, def- initely enlarged nodes seen on CT are usually regarded as reliable evidence Chapter 7 Imaging in the Evaluation of Patients with Prostate Cancer 127 of metastatic disease, especially if local tumor volume and grade suggest that metastases are likely, and if the location of the enlarged nodes is com- patible with metastatic prostate cancer. This disease tends to spread to and enlarge nodes in the pelvic retroperitoneum before causing enlargement of nodes in the abdomen or elsewhere (84). It has been well known for a long time that clinical stage, PSA, and Gleason score are independent predictors of the likelihood that metastases will be found in surgically resected lymph nodes. It seemed logical that these factors might be useful in predicting which CT scans are likely to show enlarged nodes, and, indeed, all three factors have been found to be independent predictors of CT-demonstrated lymphadenopathy (85). These ﬁnd- ings have been substantiated by another study (86), and still others (87,88) corroborate the importance of PSA; all studies suggest that in patients with an initial PSA below 20, a positive CT scan is extremely unlikely. These ﬁndings have primarily been interpreted as indicators that for these patients at low risk, CT need not be performed; they may also be useful for radiologists confronted with CT scans with marginal nodal ﬁndings; in these cases, investigation of the PSA and Gleason score may aid in reach- ing radiologic decisions. Magnetic Resonance Imaging Early in the development of body MRI it became apparent that the prostate could be visualized, and even that the zones within it could be distin- guished. Although little success was met in screening for prostate cancer, a series of publications investigated the technique as a staging technique for recently diagnosed prostate cancer. Most of these relied on external coils (89–93), which continued to be used in a later series as well (94). Staging of the local extent of disease, rather than detecting metastatic disease, was the task at hand, and the external coil was not highly accurate. Accuracy percents tended to be in the low 60’s, and many studies found no improve- ment over simply using PSA or DRE. A few investigators managed to achieve higher accuracy with body coil MRI (95,96), ﬁnding that MRI was superior to sonography and CT for evaluating seminal vesicle invasion (95) and achieving high speciﬁcities in predicting capsular penetration (80%) and seminal vesicle invasion (86%) with a moderately high sensitivity for capsular penetration (62%) (96). With the introduction of the intrarectal surface coil, the higher spatial resolution that the technique permitted improved accuracy of staging (92,97–102). Various levels of sensitivity, speciﬁcity, PPV, and NPV have been reported; overall staging accuracy ranges from 62% to 84%. Even with the rectal coil techniques, however, not all authors were enthusiastic (103,104). Detection of metastatic disease in pelvic and abdominal lymph nodes by body coil MRI suffers from the same problem as CT, which is that size is the only parameter that can be accurately measured, and that tumor is often found in nonenlarged nodes. In attempts to continue to use endorec- tal MRI to improve staging, many authors have developed staging schemes that combine the results of PSA, PSA density, Gleason score, percentage of tumor-bearing cores in a biopsy series, and age, along with MRI, and have 128 J. Statis- tics presented in support of the combinations use a variety of outcome parameters but do not permit gross comparisons of the studies, however (106–112). A combination of using highly trained observers and a computer system, without addition of non-MRI data, achieved an accuracy of 87% (113). Most studies reporting interpretation of MRI rely most heavily on T2- weighted images. In these images, the peripheral zone of the prostate, where most tumors appear and from which extracapsular extension occurs, appears bright, and tumor tissue is relatively low intensity.
Using the method of the previous example quality 50 mg avanafil, the following vector quantities were determined at time t 5 5 s: b1 5 0 buy cheap avanafil 200 mg on-line. De- termine the angular velocity of B in reference frame E and express it in terms of unit vectors in B 50mg avanafil free shipping. The component along the b2 direction may be altered by muscles that cause abduction/adduction in the frontal plane order avanafil 50mg with visa. The angular velocity com- ponents in the b3 direction, on the other hand, are dependent on the mus- cles that flex/extend the upper arm. The projections of angular velocity along the unit vectors bi are called anatomical angular velocity components. Contribution of Body Segments to the Velocity of the Endpoint An important goal of sports mechanics is to determine the relative con- tributions of body segments to the velocity of the endpoint (the midpoint of a tennis racket or the head of a golf club). The endpoint speed dis- played just before the impact results from a series of upper limb segment rotations generated by muscle torques. The task is to develop an equation that expresses racket-head speed in terms of the anatomical angular ve- locities of the trunk (t), upper arm (u), forearm ( f ), and hand (h). It is as- sumed that the racket is being held with a firm grip so that no rotation occurs between the racket handle and the hand. Three-Dimensional Motion Solution: The velocity of the elbow can be expressed in terms of the ve- locity of the shoulder and the angular velocity of the upper arm by us- ing Eqn. Similarly, we could relate the veloc- ity of the wrist to the velocity of the elbow using the same equation: EvWrs 5 EvElb 1 EvBf 3 rWrs/Elb (9. Successive use of this methodology allows us to express the velocity of the midpoint of the racket as follows: EvR 5 EvShl 1 EvBu 3 rElb/Shl 1 EvBf 3 rWrs/Elb 1 EvH 3 rR/Wrs (9. We have already seen that the angular velocity of two reference frames, say Bu and Bf, are related by the following equation: EvBf 5 EvBu 1 BuvBf (9. Videotaping of forward swing events for a competitive male tennis player show that the highest overall rotational velocity is typically ob- tained by the hand segment (40 rad/s). The greatest contributor to the racket head’s forward speed at ball contact is upper arm internal rotation (8 m/s), followed by wrist flexion (7 m/s) and upper arm horizontal ad- duction (6. In these cases, one should also incorpo- rate the rotational velocity of the trunk into the expression for the end- point velocity. The angular velocity of the trunk provides the shoulder with a velocity and it contributes additionally to the velocity of the end- point through its long moment arm. The young golf pro Tiger Woods has one of the highest rotational speeds in the game. Pro golf players rotate their shoulders and hips exten- sively during the backswing phase of hitting a golf ball. The larger the gap between the turns of the shoulder and the hip, the greater the levels of torsional deformation imposed on the upper body. The more exten- sively the large muscles of the trunk are stretched in the backswing phase, the faster the body unwinds during the downswing. Then P can be expressed using the unit vectors of E or B: P 5 EP e + EP e 1 EP e 1 1 2 2 3 3 P 5 BP b + BP b 1 BP b 1 1 2 2 3 3 The time derivatives of P in E and in B are defined as EdP/dt 5 (dEP /dt) e 1 (dEP /dt) e 1 (dEP /dt) e 1 1 2 2 3 3 BdP/dt 5 (dBP /dt) b 1 (dBP /dt) b 1 (dBP /dt) b 1 1 2 2 3 3 Angular Velocity Let b1, b2, b3 be a right-handed set of mutually perpendicular unit vec- tors fixed in a rigid body B. This definition of angular velocity leads to the fol- lowing results: Rdb /dt 5 RvB 3 b 1 1 Rdb /dt 5 RvB 3 b 2 2 Rdb /dt 5 RvB 3 b 3 3 288 9. Three-Dimensional Motion Thus, for any vector P defined in the reference frames R and B: RdP/dt 5 BdP/dt 1 RvB 3 P If a series of succesive reference frames is used in the study of motion, the following equation holds: EvB5 5 EvB1 1 B1vB2 1 B2vB3 1 B3vB4 1 B4vB5 Velocity and acceleration of two points in a rigid body are related by the following set of equations: EvP 5 EvQ 1 EvB 3 rP/Q EaP 5 EaQ 1 EaB 3 rP/Q 1 EvB 3 (EvB 3 rP/Q) where EaB is the angular acceleration of the rigid body B. The angular ac- celeration is defined by the relation EaB 5 dEvB/dt Conservation of Linear and Angular Momentum Laws of motion for a body in three-dimensional motion are as follows: SF 5 m ac SMc 5 EdHc/dt where SF is the resultant external force acting on the body, SMc is the resultant external moment with respect to the center of mass, and ac is the acceleration of the center of mass measured in the inertial reference frame E. If a point within the body is fixed in the inertial reference frame E, then the following equation also holds SMo 5 EdHo/dt where SMo and Ho represent the resultant moment and the moment of momentum about O. For three-dimensional motion, one obtains the following expression for angular momentum: Hc 5 (Ic v 1 Ic v 1 Ic v ) 1 11 1 12 2 13 3 Hc 5 (Ic v 1 Ic v 1 Ic v ) 2 21 1 22 2 23 3 Hc 5 (Ic v 1 Ic v 1 Ic v ) 3 31 1 32 2 33 3 in which Hc and v are the components of angular momentum and an- i i gular velocity of the rigid body in reference frame E written in some ref- 9. These ij elements depend only on the geometry and mass density distribution of the rigid body. The angular momentum about the fixed point O has a similar expres- sion: Ho 5 (Io v 1 Io v 1 Io v ) 1 11 1 12 2 13 3 Ho 5 (Io v 1 Io v 1 Io v ) 2 21 1 22 2 23 3 Ho 5 (Io v 1 Io v 1 Io v ) 3 31 1 32 2 33 3 As shown in the chapter, once the inertia matrix Ic is derived, the ma- ij trix Io can be obtained from the matrix Ic by using a transformation ij ij equation (Eqn. A figure skater spins about her longitudinal axis b2 with constant angular speed of 5 rad/s (Fig.
The most common of these mechanisms is postsurgical scarring cheap avanafil 200mg with mastercard, produc- ing the ill-defined and primarily descriptive diagnosis of "failed back surgery syndrome avanafil 100 mg. Many "failed" back surgeries are due to an inaccurate diagnostic as- sumption of discogenic pain in a patient whose nociceptive stimulus may have been post–disc disruption epidural fibrosis purchase 200mg avanafil with visa. An abnormal- appearing disc is not necessarily painful buy 200 mg avanafil mastercard, just as a normal-appearing disc is not necessarily nonpainful. McCarron used a dog model to demonstrate the intense inflammatory reaction that occurs in the epidural space in response to exposure to intradiscal nuclear material following disc disruption with or without discogenic pain. Degenerative disease of the discs, vertebrae, or facets can produce an inflammatory epidural response. Likewise, disc disruption with bulging, herniation, or frank extrusion can produce a space-occupying lesion identifiable by epidurography with thecal sac impingement, nerve root compression, and/or painful distention of the posterior lon- gitudinal ligament. The highly vas- cular nature of such tissue predisposes the patient to a higher risk of epidural hematoma with catheterization and mechanical disruption. A high level of suspicion must be maintained for such pathology when space-occupying lesions are identified. Therapeutic Indications and Contraindications The indications and contraindications for diagnostic epidurography with possible epidurolysis consist of one or more of the following: 1. Absence of focal neurological deficit Technical Considerations 175 A good rule of thumb is to consider that the presence of a focal neu- rological deficit requires surgical decompression until another diag- nosis is reached, while pain alone suggests a more conservative ap- proach of injection therapy such as epidurolysis. This assumes that loss of function (focal neurological deficit) is most often due to compres- sion while pain is most often inflammation. A compressed nerve root can be further compromised, perhaps permanently, with the potential barotrauma of an injection into a closed space (Figure 10. This establishes a dependable method dur- ing acquisition of basic knowledge and expertise in the therapy. Mod- ifications can be considered with greater confidence when the entire scope of the therapy is better understood. We should always draw on previous experience (both our own and that of others) in modifying and improving an original idea. The desire to modify procedures car- ries with it the responsibility to study the effects any change might have on patient outcome. The technical considerations proposed in this chapter have subtle variations from the original procedure that are identified with appro- priate rationales. These variations have been discussed with Racz and others who have considerable expertise in the field and are acceptable although not adopted universally. Technical Considerations Epidurography and epidurolysis can be performed at any level of the spine from the sacral hiatus to the foramen magnum. The details pro- vided here are generalized to all areas (sacral, lumbar, thoracic, and cervical) unless identified as specific to a particular area of the spine. Informed Consent Once it has been determined that a patient meets the accepted criteria for diagnostic epidurography, a detailed discussion of the potential A B FIGURE 10. The risks are those typically associated with an intraspinal procedure and should be made clear to the patient both verbally and in written form. Basic Laboratory Risks associated with infection and hemorrhage can be minimized with basic laboratory data. A complete blood count with differential and clotting studies should be standard and normal. Prolonged bleeding times, elevated prothrombin and partial prothromboplastin times, and platelet dysfunction should be evaluated and corrected before any in- traspinal procedure is undertaken. Patients should be asked whenever possible to stop all anticoagulants 2 weeks prior to the procedure. Per- sistent abnormalities should be referred to an internist or hematologist for evaluation. Patient Preparation and Monitoring Intravenous access is advisable in case of inadvertent subdural or in- travascular injection and for mild sedation as required.
The original technique was to use black lettering on white (a positive slide) and this is useful in situations in which the light in the lecture room can only be partially dimmed generic 200mg avanafil amex. Never use dark colours on a dark background – red on a dark blue background is a favourite combination and it is hopeless 100 mg avanafil free shipping. Remember that the road signs in the UK are yellow on a dark green background or black on a white background because these combinations have been found to be the easiest to read discount avanafil 100mg free shipping. If you are unsure about the colours to use discount avanafil 200mg mastercard, let the Department of Transport be your guide. Standard slides are mounted in 50·8 mm (2 in) square mounts, but produce rectangular images. Most slides are shown with the long axis horizontally and the short axis vertically (approximate proportions of 3:2). If you use slides with a vertical layout then you run the risk of losing the top or bottom of the slide as some lecture theatres cannot deal with this orientation. It is very irritating to see some of the slide projected on to the ceiling or floor. Finally, use the same format for all the slides, that is, the same colour combinations, typeface, layout, etc. If you want your presentation to be taken as a coherent talk then your slides must reflect this and be consistent. Do not insult the audience by presenting them with a jumble of slides, sometimes known as "pick-and-mix" slides, which you have obviously used before for many different talks. Instead of listening to the content of the lecture, the audience will be wondering on whom you last inflicted that dreadful, rainbow-coloured, illegible slide. Never use more than eight lines per slide and if at all possible stop at six lines. If necessary, divide the content between two slides rather than cram in extra lines. It is always preferable to keep to a single line for each point that you are making: you lose impact by using two or, even worse, three lines. Select a clear uncluttered typeface that can be read easily, scan some of the newspapers to gain ideas about those typefaces that can be read best at a distance. Avoid upper case text (capital letters) as this is more difficult to read quickly than lower case text. If you wish to emphasise a point, underline the relevant word; a different typeface occasionally works but can distract from the rest of the slide. If you have to explain the layout of a slide to the audience then you have failed. The same general principles apply to figures as to the text: the colour combinations must be consistent throughout the presentation and it is essential to avoid overcrowding the figures. Because the editor of a journal insisted that you combine four small graphs into a single figure does not mean that you should inflict the same layout on the audience. The decision of the editor was based on the need to save space in the journal; your objective is completely different – that of imparting information with clear, unambiguous slides, so the rule is one graph for one slide. Complicated pie charts often look impressive in publications but are not suitable for slides because it is difficult for the audience to assimilate the information rapidly. It is preferable to use different symbols for different lines on a graph rather than different colours. Although it seems instinctive to consider different colours for different lines, this only works if the lines are well separated. If possible try to give an indication of the variability of the data but look carefully to be certain that this does not make the slide messy and detract from the message. If necessary, you simply tell the audience that the data on the variability of the results are available and that they will have to trust your statistical analysis for the presentation. All labels should be written horizontally, abbreviated if necessary – unless you like inducing neck injuries in the audience – and should be self-explanatory. You undoubtedly remember whom groups 1-4 were, but most of the audience forgot 15 minutes ago, so label them appropriately – for example: sober, mildly drunk, very drunk, and members of college council. Avoid whizzy 3-D options: in most instances they add nothing to the presentation and just tell the audience that you are an anorak who reads the software manual.
Level IV: insufﬁcient evidence Studies with multiple ﬂaws in research methods discount avanafil 100mg, case series order avanafil 100 mg mastercard, descriptive studies avanafil 200 mg on-line, or expert opinions without substantiating data avanafil 50 mg cheap. What is the performance of percutaneous image-guided breast biopsy compared with standard surgical excisional biopsy? What type of imaging guidance is best suited for breast lesions manifest as masses or as microcalciﬁcations? Special case: biopsy of breast lesions detected on breast mag- netic resonance imaging XII. Key Points Mammography Prospective randomized controlled trials have demonstrated reduced breast cancer mortality of approximately 30% associated with mam- mography screening (strong evidence). Women aged 40 to 54 should be screened at intervals of 12 to 18 months in order to achieve similar mortality reductions compared with women 55 years of age and older due to faster tumor growth in younger women (moderate evidence). Ultrasound Data from single center studies of screening ultrasound suggest that it has a detection beneﬁt as a supplement to screening mammogra- phy in patients with dense (at least 50% of the breast is not fatty) breast parenchyma (moderate evidence). Reports from single-institution studies found a high percentage (91%) of breast cancers identiﬁed on supplemental screening sonography are stage I invasive cancers. Detecting this subset of breast cancers is most likely to reduce breast cancer mortality (moderate evidence). In patients with dense breast parenchyma, mammography and sonography appear complementary in that ductal carcinoma in situ (DCIS) is better depicted by mammography and small, <1cm, inva- sive breast cancers are better detected sonographically (moderate evidence). Women with dense breast parenchyma on mammography, contem- plating a supplemental sonographic screening examination, should consider the risk of a false-positive sonogram, possibly resulting in the recommendation for a breast biopsy (moderate evidence). Sonography is appropriate in the evaluation of palpable breast masses (moderate evidence). Sonography is appropriate in the evaluation of mammographically circumscribed, obscured, or indistinctly marginated masses and focal asymmetries (moderate evidence). The combination of mammography and sonography depicts 96% to 97% of palpable breast cancer and 92% of nonpalpable breast cancer (moderate evidence). Sonography can help identify the invasive component of mixed inva- sive and intraductal carcinoma and guide optimal percutaneous biopsy (limited evidence). Sonography is a useful supplement to mammography in depicting the extent of invasive carcinoma in dense breasts (moderate evidence). Sonography is useful in the evaluation of the patient with nipple dis- charge (limited evidence). Biopsy Percutaneous image-guided breast biopsy is not indicated for non- palpable lesions classiﬁed as BIRADS 3. For these lesions, short-term interval follow-up, generally at 6-month intervals, is recommended (strong evidence). For BIRADS 4 and 5 lesions, image-guided percutaneous biopsy is cost-effective as the initial strategy for diagnosing nonpalpable breast lesions (strong evidence). Pathophysiology and Epidemiology Breast cancer takes a tremendous toll in the United States. For 2004, the American Cancer Society predicted that 217,440 new cases of breast cancer would be diagnosed, and 40,580 individuals would die from the disease (1). Mammographic screening remains controversial, as reﬂected in greatly varying national policies. The speciﬁcity and positive predictive value of mammography are limited because of overlap in the appearance of benign and malignant breast lesions (2–4). However, until research uncovers a way to better cure or prevent breast cancer, early detection is viewed as the best hope for reducing the burden of this disease. The Gail (5–8), Claus (9), and other models have been developed to calculate a woman’s risk of breast cancer primarily as a function of age and family history. The risk of developing breast cancer nearly doubles with a family history of breast cancer in a ﬁrst-degree relative (10). Women with a personal history of breast cancer, and those with prior biopsies showing atypical ductal hyperplasia (ADH) or atypical lobular hyperplasia (ALH), are at a four- to ﬁvefold increased risk of breast cancer (10). Women with prior lobular car- cinoma in situ (LCIS) are also at high risk of breast cancer, with rates of eight- to 10-fold those of women without such risk (11). Such high-risk women are candidates for chemoprevention with agents such as tamoxifen.