Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/48—Diagnostic techniques
  • A61B6/481—Diagnostic techniques involving the use of contrast agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/50—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications
  • A61B6/501—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment specially adapted for specific body parts; specially adapted for specific clinical applications for diagnosis of the head, e.g. neuroimaging or craniography
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
  • A61B6/52—Devices using data or image processing specially adapted for radiation diagnosis
  • A61B6/5211—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data
  • A61B6/5217—Devices using data or image processing specially adapted for radiation diagnosis involving processing of medical diagnostic data extracting a diagnostic or physiological parameter from medical diagnostic data
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K51/00—Preparations containing radioactive substances for use in therapy or testing in vivo
  • A61K51/02—Preparations containing radioactive substances for use in therapy or testing in vivo characterised by the carrier, i.e. characterised by the agent or material covalently linked or complexing the radioactive nucleus
  • A61K51/04—Organic compounds
  • A61K51/041—Heterocyclic compounds
  • A61K51/044—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine, rifamycins
  • A61K51/0455—Heterocyclic compounds having nitrogen as a ring hetero atom, e.g. guanethidine, rifamycins having six-membered rings with one nitrogen as the only ring hetero atom
• • G—PHYSICS
  • G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
  • G16H—HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA
  • G16H50/00—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics
  • G16H50/20—ICT specially adapted for medical diagnosis, medical simulation or medical data mining; ICT specially adapted for detecting, monitoring or modelling epidemics or pandemics for computer-aided diagnosis, e.g. based on medical expert systems

Definitions

• the present invention relates to radiopharmaceutical imaging of the brain, in particular to dopamine transporter imaging of the striatum (or a portion thereof).
• a method of imaging to permit calculation of left : right striatum uptake ratios is provided, and the degree of asymmetry used to assist in the diagnosis of neurological diseases.
• Dopamine transporter imaging radiopharmaceuticals and brain imaging using such imaging agents have been described extensively in the art since the early 1990s.
• Laruelle et al [J.Cereb.Blood Flow Metab., 14, 982-984 (1994)] used the agent 123 ⁇ - ⁇ - CIT and a ratio of striatal-to-background activity to give a figure proportional to dopamine transporter density.
• SBR specific bind ratio or striatum binding ratio
• ROI region of interest.
• radiopharmaceutical 99m Tc-TRODAT-l They calculated a left/right ratio of specific uptake ratio after surgical intervention based on animal sacrifice and counting of tissue samples. The animal control group had been subjected to sham surgery and were not a true normal dataset.
• Parkinson's disease Gleave et al calculated an "altropane ratio" of the left to right side based on animal sacrifice, and tissue sample counting with subtraction of cerebellum uptake from the striatal counts, to give specific uptake, before calculation of the left/right ratio.
• the left / right ratios were compared with animal behaviours, but no comparison with a normal control was performed.
• Soderlund et al [J.Nucl.Med., 54(5), 714-722 (2013)] advocate a combined approach based on: (i) visual assessment of patient scans, (ii) semi-quantitative assessment based on SBR (based on striatum uptake with occipital cortex uptake as the reference region), and CPR (caudate-to- putamen ratio). They suggest that this reduces intra-observer variability.
• Correction factors may be needed to permit comparison of SBR and similar ratios obtained using different camera systems within a single imaging facility and between different sites.
• Associated software tools have been studied extensively. These are discussed by Zaknun et al [Quart, J.Nucl.Med.Mol.lmagmg, 5J_, 194-203 (2007)] and Tatsch et al (vide supra).
• Y & Z are the striatal binding indexes (SBIs) for the 2 different sides.
• the SBI is calculated from the ipsilateral (same side) caudate and putamen ROI radioactivity counts, using the algorithm:
• O mean counts per pixel in the occipital cortex (background).
• SAI striatal asymmetry index
• radiopharmaceutical declines with age. Such comparison requires the use of normal image databases. Such databases are, however, only really meaningful for a coherent set of data, which may well mean the same camera, same software, same imaging protocol etc.
• radiopharmaceutical in the brain is quantified, the values obtained vary significantly depending on the camera configuration and set-up, image acquisition parameters, and many other factors. It has therefore so far proved impossible to establish a meaningful normal database that is built on data from more than one camera type, without considerable effort to apply 'correction factors'.
• the present invention is based on the observation that left : right symmetry of striatum uptake in the normal patient population is maintained independent of the age and gender of the patient.
• This symmetrical left/right striatum uptake is shown to be independent of camera type and image acquisition parameters, and is proposed as a more robust way to generate both a normal database and patient comparator data - wherein imaging data can be compared without the need for complex correction factors.
• Visual assessment of dopamine transporter radiopharmaceutical images is generally used to determine whether brain uptake patterns are normal or abnormal.
• SBR average striatum binding ratio
• a problem with this method is that average striatum binding ratio (SBR) and related values vary significantly between camera types, and even between the same camera type at different clinical sites - even when the same radiopharmaceutical is used.
• SBR average striatum binding ratio
• the reason for such a wide variation is not yet fully understood, but factors such as collimator type and image reconstruction methodology have been suggested.
• the consequence is that the 'average' value of SBR cannot easily be transferred from one site to another as a comparator for the subject.
• a normal database that is constructed with data from more than one site shows a very wide spread of values for average SBR and associated regions of interest, such as entire striatum, putamen or caudate.
• the standard deviation of 'normal' SBR even from a single site and camera is large - due to the natural variation within the normal human population. If the data set includes data from multiple cameras/sites, then the statistical variation becomes wider still.
• the effect is that a subject with e.g. early PD and a relatively low level of reduced striatal uptake may lie within the apparently 'normal' population of such a data set (i.e. within 1 to 2 standard deviations of the mean value), when a more statistically robust, coherent normal data set would have flagged the deviation from normal uptake.
• the present invention is based on an analysis of left-right symmetry of striatal uptake. Surprisingly, the left-right symmetry of such uptake has been found to be maintained in healthy subjects irrespective of subject age and gender. Thus, for a normal population, the ratio left striatum: right striatum (absolute or SBR) is close to 1.0 with low standard deviation. This has been found to hold true even when patient image data from different clinical sites and/or different camera systems are used.
• a further advantage is that when comparing leftright uptake values, absolute values can be used rather than comparing targetbackground ratios. That eliminates the need for more complex calculations, and reduces statistical variation due to subtraction of two numbers, each having an associated error bar. This is particularly important with respect to the counts in the background/reference region. Those counts will be intrinsically low - hence the error bar or "noise" is relatively large. Furthermore, the conventional SBR calculates two ratios, so the error bar is compounded by the calculation. Subtraction of such a figure therefore introduces a statistical variation. Differences introduced through variations in background in left and right hemispheres are thereby avoided, and an even narrower distribution of the normal data can be expected.
• the method of the present invention does not require analysis to carry out comparison with age-matched and gender-matched patients/controls. That is because the striatum L/R ratio is close to 1.0 in normal subjects regardless of age and gender. This is a useful simplification. Furthermore, whereas the diagnostics described hereinabotulinum L/R ratio is close to 1.0 in normal subjects regardless of age and gender.
• the present invention provides a method of imaging useful in the diagnosis of neurological disease, which comprises:
• step (ii) comparing the ratio for said subject from step (iii) with a normal range of such ratios for normal subjects.
• method of imaging is meant a method which generates images of the subject - typically two-dimensional or three-dimensional, in colour or black and white, preferably colour.
• the images may be of the whole subject or a part thereof, i.e. a region of interest (ROl).
• the ROl is suitably the brain of the subject or a region within said brain.
• neurological disease is meant a disorder with pathological features affecting brain function such as dementia, movement disorders or drug-induced disorders of the human or mammalian body. These include, but are not limited to: Parkinson's disease; Parkinson's syndromes (progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration); Lewy body dementia (DLB); Alzheimer's disease and AD-HD.
• Parkinson's disease Parkinson's syndromes (progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration); Lewy body dementia (DLB); Alzheimer's disease and AD-HD.
• DLB Lewy body dementia
• AD-HD Alzheimer's disease
• the unequivocal diagnosis of these during life can be difficult, due to overlapping symptoms of other diseases such as Essential Tremor, Alzheimer's disease and drug induced or vascular Parkinsonism.
• Essential Tremor Alzheimer's disease and drug induced or vascular Parkinsonism.
• subject is meant a mammal in vivo, preferably the intact mammalian body in vivo, and more preferably a living human subject.
• normal range is as defined in the second aspect (below).
• radiopharmaceutical has its' conventional meaning, and refers to an imaging agent wherein the imaging moiety is a radioisotope.
• radiopharmaceutical is labelled with a radioisotope suitable for medical imaging in vivo.
• imaging agent is meant a compound suitable for imaging the mammalian body. Such imaging agents are designed to have minimal
• the imaging agent can be administered to the mammalian body in a minimally invasive manner, i.e. without a substantial health risk to the mammalian subject when carried out under professional medical expertise.
• Such minimally invasive administration is preferably intravenous administration into a peripheral vein of said subject, without the need for local or general anaesthetic.
• dopamine function imaging dopaminergic neurons of the midbrain, in particular: dopamine synthesis; dopamine storage and dopamine reuptake. These are assessed by the following types of radiopharmaceutical respectively:
• the dopamine function is preferably presynaptic dopamine function.
• DOPA decarboxylase activity radiopharmaceutical refers to radiotracers which show the metabolism of the drug DOPA (Z-3,4-dihydroxyphenylalanine). Such tracers may be DOPA itself labelled with 18 F ( 18 F-DOPA also known as 18 F- FDOPA), or n C ( n C-DOPA), or analogues thereof. These are described by Elsinga et al [Curr.Med.Chem., 13, 2139-2153 (2006)]. The synthesis of 18 F-FDOPA is described by Kao et al [Ann.Nucl.Med., 25(5), 309-316 (2011)].
• VMAT2 refers to the vesicular monoamine transporter type 2.
• VMAT2 binding radiopharmaceutical refers to a radiopharmaceutical suitable for imaging VMAT2. Suitable such radiopharmaceuticals include
• dihydrotetrabenazine compounds labelled with n C or 18 F such as [ n C]- dihydrotetrabenazine ([ n C]DTBZ) [Hefti et al, PET Clin., 5(1), 75-82 (2010)].
• An automated synthesis of n C-DTBZ is described by Zhang et al [Molecules, 17(6), 6697-6704 (2012)].
• 18 F-fluoroalkyl dihydrotetrabenazine derivatives are described by Kilbourn et al [Nucl.Med.Biol., 34(3), 233-237 (2007)], Goswami et al
• PET radiotracer [ 18 F]AV-133 [(+)-2-Hydroxy-3-isobutyl-9-(3-fluoropropoxy)-10-methoxy-l,2,3,4,6,7-hexahydro- 1 lbH-benzo[a]quinolizine:
• dopamine transporter radiopharmaceutical has its' conventional meaning in the field of radiopharmaceutical imaging. It refers to an imaging agent for the presynaptic dopamine transporter system in vivo, also known as the dopamine reuptake system.
• the dopamine transporter system is described by Elsinga et al
• assessing the uptake refers to techniques for detecting the radioactive emissions from the radiopharmaceutical within the subject. This is suitably carried out using a gamma camera or positron emission camera as is known in the art.
• the uptake measured is preferably the absolute uptake - without background correction or background subtraction being carried out.
• the uptake is also measured for the left and right 'equivalent region' concurrently, and for a defined period of time - i.e. the same acquisition start time and finish time.
• striatum has its conventional meaning, and refers to a subcortical part of the brain.
• the striatum is divided into two sectors: the caudate nucleus and putamen, which are divided by a white matter tract called the internal capsule.
• left and right follow conventional clinical practice and refer to the patient's left side, and the patient's right side respectively.
• medical tomographic imaging it is conventional to view two-dimensional images which display horizontal 'slices' of the uptake of the radiopharmaceutical at various positions within the patient's brain.
• these tomographic slices each have a left and a right side corresponding to the subject's left and right side and left and right hemisphere of the brain.
• Brain tomographic imaging is described in Functional Cerebral SPECT and PET Imaging [Van Heertum et al (eds), 4 th Edition, Lippincott Williams and Wilkins (2009)], and Neuroimaging in Dementia [Barkhof et al, Springer (2011)].
• Equivalent region is meant a region of the same volume (for 3- dimensional imaging) or the same area (for 2-dimensional imaging), on the left and right side of the brain. This could be as an area of interest (AOI), volume of interest (VOI) or region of interest (ROI).
• Software tools are known in the art to assist in such methodology. Such software tools are commercially available - typically from the commercial supplier of the gamma camera or positron camera. Other such software tools are described by Tatsch et al [Quart. J.Nucl.Med., 56(1), 27-38 (2012)].
• the size of the 'equivalent region' is up to the size of the whole striatum or a portion thereof.
• the person skilled in the art will know that the minimum such 'equivalent region' chosen will be dictated by good counting statistics - i.e. where the radioactive counts detected are well above general background. This is governed by variables such as: the amount of radioactivity administered; the emission characteristics of the radioisotope; the sensitivity of the camera; the acquisition time, the radius of rotation of the detectors on certain cameras etc. Consequently, direct comparison of the two uptake figures (left and right), is representative of the relative uptake in the left and right striatum. It does not matter whether one calculates A/B (i.e. left/right) or B/A (i.e. right/left) ratio - as long as a consistent approach is taken. The ratio calculated in the present method thus provides a measure of left/right asymmetry in the subject image.
• the method of the first aspect may be carried out on the same subject on one or more occasions, i.e. at different time intervals. Multiple such determinations on the same subject permit the longitudinal monitoring of a neurological disease, i.e. of disease progression. This can be carried out with or without therapy.
• the former is described as the fourth aspect (below). Preferred embodiments.
• the radioisotope of the radiopharmaceutical is preferably suitable for either PET or SPECT imaging in vivo.
• radiopharmaceuticals are often also termed 'radiotracers'.
• the radioisotope can be metallic (i.e. a radiometal), or a non-metal.
• suitable radiometals can be either positron emitters such as 64 Cu, 48 V, 52 Fe, 55 Co, 94m Tc or 68 Ga; ⁇ -emitters such as 99m Tc, m In, 113m In, or 67 Ga.
• Preferred radiometals are 99m Tc, 64 Cu, 68 Ga and m In.
• Most preferred radiometals are ⁇ -emitters, especially 99m Tc.
• the imaging moiety When the imaging moiety is a non-metal, it can be a gamma-emitter or a positron emitter.
• Gamma-emitting radiohalogens are suitably chosen from 123 I, 131 I or 11 Br.
• a preferred gamma-emitting radioactive halogen is 123 I.
• suitable such positron emitters include: n C, 13 N, 15 0, 17 F, 18 F, 75 Br, 76 Br or 124 I.
• Preferred positron-emitting radioactive non- metals are n C, 13 N, 18 F and 124 I, especially n C and 18 F, most especially 18 F.
• the radiopharmaceutical suitable for imaging dopamine function is preferably a VMAT2 imaging radiopharmaceutical, or a dopamine transporter imaging radiopharmaceutical, more preferably a dopamine transporter imaging radiopharmaceutical.
• radiopharmaceutical preferably comprises a radio labelled tropane, and more preferably comprises a 3-phenyltropane.
• the term "tropane” has its conventional meaning in the art. PET tropanes have been reviewed by Riss et al.
• the dopamine transporter radiopharmaceutical preferably comprises a radioisotope chosen from 123 I or 99m Tc for SPECT, or 18 F or 1 ! C for PET, more preferably 123 I or 18 F.
• the dopamine transporter radiopharmaceutical preferably comprises: 123 I- ioflupane (DaTSCANTM), 18 F-ioflupane, 123 I-Altropane, 123 I-PE2I, n C-PE2I, 123 I-IPT, 123 I-P-CIT, 18 F-P-CFT, 99m Tc- TROD AT or 99m Tc-technepine.
• the 123 ⁇ ⁇ dopamine transporter radiopharmaceutical comprises I-ioflupane (DaTSCAN ), 18 F-ioflupane or 123 I-Altropane, most preferably 123 I-ioflupane (DaTSCANTM) or 123 I- Altropane, with 123 I-ioflupane (DaTSCANTM) being the ideal.
• DaTSCAN I-ioflupane
• DaTSCANTM 123 I-ioflupane
• DaTSCANTM 123 I-ioflupane
• step (ii) of the method of the first aspect “assessing the uptake” is preferably based on the absolute uptake as described above.
• the method of the first aspect preferably excludes further analysis to carry out comparison with age-matched and gender- matched patients/controls, or to correct for camera type.
• the striatum appears comma-shaped - with the caudate as the dot/ball-shaped part of the comma, and the putamen as the tail of the comma.
• the equivalent region of step (ii) is preferably chosen from:
• the equivalent region of step (ii) is the putamen, and most preferred the posterior putamen. That is because the caudate exhibits the highest uptake, even in Parkinson's syndrome patients - whereas putamen uptake tends to decline with the progression of Parkinson's diseases. Thus, the putamen is most likely to be the first to show asymmetric uptake, in particular the posterior putamen. Hence, using a left/right ratio based on putamen uptake is the most sensitive indicator of PD, and may permit early diagnosis - before perhaps clinical symptoms become evident.
• step (ii) is the combination of all the following:
• the assessing of step (ii) and/or the calculating of step (iii) is preferably carried out via tomographic imaging, more preferably positron emission tomography (PET) or single photon emission tomography (SPECT).
• PET positron emission tomography
• SPECT single photon emission tomography
• the method of the first aspect preferably further comprises one or more of the following: (I) calculating a caudate :putamen or putamen: caudate ratio for the left and right striatum separately;
• the dopamine transporter radiopharmaceuticals of the first aspect can be obtained as
• DatScan I-ioflupane
• Other agents can be prepared via the methods cited above, as well as the references cited by Shen et al [J.Biomed.Biotechnol, Article 259349 (2012)], and Nikolaus et al, [Rev.Neurosci., 18, 439-472 (2007)].
• the present invention provides a method of diagnosis which comprises the method of imaging of the first aspect, where the comparing of step (iv) is with a database of such ratios, wherein said database contains such ratios for normal subjects; and which further comprises:
• step (v) when the ratio from step (iv) is within the normal range, said subject is classified as having a normal presentation;
• step (vi) when the ratio from step (iv) is outside the normal range, the patient is classified as suffering from a neurological disease.
• the database of step (iv) of the second aspect suitably comprises the ratio of step (iii) for a group of normal subjects, and preferably further comprises such ratios for patients having a known, defined neurological condition.
• An important advantage of the present invention is that such ratios can readily be compiled from a range of clinical datasets, even if collected on different cameras, without the need for correction factors. This facilitates the compilation of a larger, usable dataset - which in turn means the data within the database carries a more powerful statistical significance.
• the database comparison is suitably carried out using the software tool of the fifth aspect.
• normal range refers to the uptake ratio of the first aspect for the normal subjects within the database.
• the ordinary person skilled in art can choose a suitable confidence limit, but a 95% confidence limit corresponding to approximately ⁇ 2 standard deviations of the mean from the normal range, is often selected.
• normal presentation is meant that the left/right ratio determined for the subject under diagnosis is within the normal range. This indicates that, either the subject is normal, or that the patient is suffering from a neurological condition which exhibits a symmetric pattern. Thus, certain neurological conditions exhibit a 'normal' striatum left/right ratio, i.e. close to 1.0.
• neurological diseases where the left/right ratio of step (iii) is expected to fall outside the normal range are: Parkinson's disease or Parkinson's syndromes such as Multiple System Atrophy (MSA) and Progressive Supranuclear Palsy (PSP).
• MSA Multiple System Atrophy
• PSP Progressive Supranuclear Palsy
• examples of neurological diseases where the left/right ratio of step (iii) is expected to fall within the normal range are: drug-induced parkinsonism, vascular pseudo-parkinsonism, Alzheimer's disease, essential tremor (ET) and DLB.
• the finding of a "normal presentation” can be used to exclude certain neurological conditions which do exhibit an asymmetric ratio, and thus differentiate PD, MSA and PS for such subjects. In combination with the subject's other clinical symptoms, and/or further medical imaging or testing, this information may still be valuable in patient diagnosis and management.
• the SAI as defined above
• the striatum left/right ratio is expected to show a 'normal presentation' but further analysis, in particular determination of the SBR is expected to be valuable - since the SBR is expected to be low for such subjects.
• the finding of a 'normal presentation' can then be put into context using other tests, such as additional steps (I)-(IV) of the first aspect - to seek to finalise the diagnosis.
• the present invention provides a method of selecting or excluding a subject for a particular therapy of a neurological disease, which comprises the method of imaging of the first aspect, or the method of diagnosis of the second aspect.
• Preferred embodiments of the method of imaging and the radiopharmaceutical suitable for imaging presynaptic dopamine function in the method of selection of the third aspect are as described in the first aspect (above).
• Preferred embodiments of the method of diagnosis in the third aspect are as described in the second aspect (above).
• Preferred embodiments of the neurological disease in the third aspect are those diseases described in the second aspect as showing left/right asymmetry, i.e.
• Parkinson's disease or Parkinson's syndromes are Parkinson's disease or Parkinson's syndromes.
• the appropriate therapy for the disease is selected for the subject.
• the third aspect also includes excluding from anti-Parkinsonian therapy a subject shown to have an apparently normal L/R striatal ratio using the methods of the first or second aspect. This exclusion is important, since it helps avoid misdiagnosis and unsuitable therapies which cannot benefit the subject, and only risk causing harm.
• the third aspect also includes deselecting from therapy a subject already undergoing therapy for a neurological condition, whose existing course of treatment/therapy, is found to be unsuitable after the imaging of the first aspect, or the diagnosis of the second aspect establishes that the treatment/therapy is misdirected due to a previous misdiagnosis. This is particularly important if e.g. the subject has been misdiagnosed with PD, and is receiving anti-Parkinson's medication or therapy - but is found by the method(s) of the invention to be suffering from a different condition.
• the present invention provides a method of monitoring the efficacy of a course of therapy of a neurological disease of a subject, which comprises the method of imaging of the first aspect, or the method of diagnosis of the second aspect.
• Preferred embodiments of the method of imaging and the radiopharmaceutical suitable for imaging presynaptic dopamine function in the method of monitoring of the fourth aspect are as described in the first aspect (above).
• Preferred embodiments of the method of diagnosis in the fourth aspect are as described in the second aspect (above).
• Preferred embodiments of the neurological disease in the fourth aspect are those diseases described in the second aspect as showing left/right asymmetry, i.e. Parkinson's disease or Parkinson's syndromes.
• the present invention provides a software tool suitable for carrying out:
• Preferred embodiments of the method of imaging and the radiopharmaceutical suitable for imaging presynaptic dopamine function in the fifth aspect are as described in the first aspect (above).
• Preferred embodiments of the method of diagnosis in the fifth aspect are as described in the second aspect (above).
• the software tool of the fifth aspect preferably runs on a personal computer, a gamma camera or a PET camera workstation.
• the software tool of the fifth aspect preferably comprises the database of L/R ratios described in the second aspect.
• the present invention provides the use of the radiopharmaceutical suitable for imaging presynaptic dopamine function of the first aspect, in one or more of:
• the present invention provides the use of the software tool as defined in the fifth aspect in one or more of:
• Preferred embodiments of the method of imaging and the radiopharmaceutical suitable for imaging presynaptic dopamine function in the seventh aspect are as described in the first aspect (above).
• Preferred embodiments of the method of diagnosis in the seventh aspect are as described in the second aspect (above).
• the present invention provides the use of a tomographic imaging device in one or more of: (i) the method of imaging of the first aspect;
• Preferred embodiments of the method of imaging and the radiopharmaceutical suitable for imaging presynaptic dopamine function in the eighth aspect are as described in the first aspect (above).
• Preferred embodiments of the method of diagnosis in the eighth aspect are as described in the second aspect (above).
• the present invention provides a database as described in the second aspect.
• Figure 1 shows the prior art SBR determination for normal human subject imaging data. This shows a considerable spread of values, and a variation with the age of the subject.
• Figure 2 shows the striatum L/R ratio calculation for the same data set as Figure 1.
• Figure 3 shows the left and right striatal binding values from the normal data set of Example 3.
• the data from Subject 1 of Example 4 a male 79 years old Parkinson's patient based on clinical diagnosis, (solid circle and triangle, respectively, also marked by the arrows) are included for comparison.
• Subject 1 is an illustrative example. It can be seen that, based on SBR alone, Subject 1 's ratios are within the normal ranges as indicated by the hollow diamonds and squares.
• Figure 4 shows the asymmetry index (or normalised left-right asymmetry) of the normal data set of Example 3.
• Subject 1 is illustrative data from Example 5.
• the data for Subject 1 (see Figure 3; solid square, pointed out by arrow) is clearly outside the range given by the normal values (hollow diamonds), hence indicating abnormality of Subject 1 's DaTSCAN image that would not be obvious when merely studying striatal binding ratio alone as per Figure 3.
• Figure 5 shows the ratio of uptake in the posterior putamen to the caudate for the normal group, with data for Subject 1 superimposed.
• the normal range is defined by the hollow diamonds (left striatum) and hollow squares (right striatum).
• Example 1 is a comparative Example which shows the calculation of SBR using data from: (i) a range of camera manufacturers (Group A); (ii) a single manufacturer (GE; Group B) and (iii) a patient.
• the variation in Group A is so wide that there is almost no value in it for comparison with patient data. Even with Group B, the normal range is too wide to be useful for comparative purposes. This demonstrates the difficulties with the current methodology.
• Example 2 applies the method of the present invention.
• Table 3 of Example 2 shows calculation of the righ left ratios, showing that the variation of the ratio for the normal population is indeed much narrower than the variation of the absolute values and is independent of site and camera type.
• Example 1 shows that the 'normal' distribution for SBR is very wide (23-24% RSD i.e. Relative Standard Deviation) and non-uniform across age groups.
• the ratio SBR left: SBR right is relatively narrow (4% RSD) and uniform across age groups.
• the lefhright ratio of the invention is therefore a more sensitive tool for detecting deviation from normality.
• Example 3 and Figures 3 and 4 show that the L/R asymmetry ratio of the present invention is stable in the cohort of normal subjects irrespective of age, whereas the SBR method of the prior art tends to decline with age (from about 3.2 in the thirties group to about 2.2 in the eighties age group) - necessitating age corrections when data comparisons are made.
• Example 4 shows that, based on SBR alone, 17 subjects were clinically 'abnormal' but were classified as normal when applying the SBR rules from the normal database. The result is low sensitivity. Only 2 clinically normal cases were wrongly classified as abnormal by the SBR method.
• Example 5 shows that, when the method of the present invention is used, the number of wrongly classified clinically abnormal cases reduces from 17 to 5, i.e. 12 subjects had a changed classification as a result of involving the asymmetry determination. That is a significant improvement in the correlation of the clinical and imaging classifications.
• the use of the asymmetry index also classifies some clinically 'normal' cases as 'abnormal', hence reducing specificity.
• the clinical standard of truth is not perfect, especially e.g. for subjects that may be converting to disease but do not as yet show any clinically abnormal symptoms.
• the abnormal DaTSCAN result is an early indicator of future abnormal clinical status even though these subjects do not yet show any clinical symptoms.
• AD Alzheimer's disease
• AD-HD attention deficit hyperactivity disorder
• AOI area of interest
• DaT dopamine transporter
• DLB Lewy body dementia
• DOPA L-3 ,4-dihydroxyphenylalanine
• MSA Multiple System Atrophy
• NDB Normal Database
• PET positron emission tomography
• PD Parkinson's disease
• PS Parkinsonian syndromes
• PSP Progressive Supranuclear Palsy
• SAI striatal asymmetry index
• SBR striatum binding ratio
• VMAT2 vesicular monoamine transporter type 2
• VOL volume of interest VOL volume of interest.
• Example 1 Striatal Binding Ratios: Normal Range (comparative Example).
• the ENCDAT database includes 150 normal subjects - with data from a range of camera types. SBR was calculated for the 150 normal subjects (Group A):
• SBR specific binding ratio or striatum binding ratio
• ENCDAT database was used for the calculation of SBR (Group B). SBR for an illustrative patient from the ENCDAT database is also shown:
• Figure 1 shows the variation of SBR with age for the normal patient group in the ENCDAT data set. The 95% confidence interval is shown, and can be seen to be wide.
• Example 2 Striatal Left/Right Binding Ratio.
• Example 1 Using the method of the present invention, the data from Example 1 was used to calculate a striatum right: left ratio:
• Table 3 below uses SBR data for normal subjects from the ENC DAT database. Three subjects from each of five different sites are shown, but the overall average is based on data from 11 sites:
• Site 1 Ankara Infinia
• Site 2 Copenhagen IRIX
• Site 3 Genoa Varicam
• Site 4 Leuven IRIX
• %RSD st dev x 100/mean.
• NDB Normal Database
• the PPMI database was of 122 subjects (age range 31-84; 62% male 38% female).
• the ENCDAT database was of 122 subjects (age range 20-82; 52% male 48% female). The data from all subjects in each decade of life (20s, 30s etc) were averaged. The results are shown in Figures 3 and 4.
• Example 4 Patient Classification Using NIP and SBR (Comparative Example).
• Example 5 Patient Classification Using NIP and L/R Ratio.

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